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Sample records for hydrothermal vent site

  1. Discovery of new hydrothermal vent sites in Branseld Strait, G.P. Klinkhammer aY

    E-print Network

    Keller, Randall A

    Discovery of new hydrothermal vent sites in Brans¢eld Strait, Antarctica G.P. Klinkhammer aY *, C 2001 Abstract We carried out a search for hydrothermal vents in the Central Basin of Bransfield Strait (2001) 395^407 www.elsevier.com/locate/epsl #12;Keywords: Brans¢eld Strait; hydrothermal vents

  2. Expansion of the geographic distribution of a novel lineage of O-Proteobacteria to a hydrothermal vent site on

    E-print Network

    Reysenbach, Anna-Louise

    Abstract The diversity associated with a microbial mat sample collected from a deep-sea hydrothermal vent an in situ growth chamber deployed on a deep-sea hydrothermal vent on the Mid-Atlantic Ridge in 1995. The similarity between phylotypes identified from Atlantic and Pacific deep-sea hydrothermal vent sites indicates

  3. First hydrothermal discoveries on the Australian-Antarctic Ridge: Discharge sites, plume chemistry, and vent organisms

    NASA Astrophysics Data System (ADS)

    Hahm, Doshik; Baker, Edward T.; Siek Rhee, Tae; Won, Yong-Jin; Resing, Joseph A.; Lupton, John E.; Lee, Won-Kyung; Kim, Minjeong; Park, Sung-Hyun

    2015-09-01

    The Australian-Antarctic Ridge (AAR) is one of the largest unexplored regions of the global mid-ocean ridge system. Here, we report a multiyear effort to locate and characterize hydrothermal activity on two first-order segments of the AAR: KR1 and KR2. To locate vent sites on each segment, we used profiles collected by Miniature Autonomous Plume Recorders on rock corers during R/V Araon cruises in March and December of 2011. Optical and oxidation-reduction-potential anomalies indicate multiple active sites on both segments. Seven profiles on KR2 found 3 sites, each separated by ˜25 km. Forty profiles on KR1 identified 17 sites, some within a few kilometer of each other. The spatial density of hydrothermal activity along KR1 and KR2 (plume incidence of 0.34) is consistent with the global trend for a spreading rate of ˜70 mm/yr. The densest area of hydrothermal activity, named "Mujin," occurred along the 20 km-long inflated section near the segment center of KR1. Continuous plume surveys conducted in January-February of 2013 on R/V Araon found CH4/3He (1 - 15 × 106) and CH4/Mn (0.01-0.5) ratios in the plume samples, consistent with a basaltic-hosted system and typical of ridges with intermediate spreading rates. Additionally, some of the plume samples exhibited slightly higher ratios of H2/3He and Fe/Mn than others, suggesting that those plumes are supported by a younger hydrothermal system that may have experienced a recent eruption. The Mujin-field was populated by Kiwa crabs and seven-armed Paulasterias starfish previously recorded on the East Scotia Ridge, raising the possibility of circum-Antarctic biogeographic connections of vent fauna.

  4. Lithosphere-biosphere interaction at a shallow-sea hydrothermal vent site; Hot Lake, Panarea, Italy

    NASA Astrophysics Data System (ADS)

    Huang, Chia-I.; Amann, Rudolf; Amend, Jan P.; Bach, Wolfgang; Brunner, Benjamin; Meyerdierks, Anke; Price, Roy E.; Schubotz, Florence; Summons, Roger; Wenzhöfer, Frank

    2010-05-01

    Deep-Sea hydrothermal systems are unique habitats for microbial life with primary production based on chemosynthesis and are considered to be windows to the subsurface biosphere. It is often overlooked, however, that their far more accessible shallow-sea counterparts are also valuable targets to study the effects of hydrothermal activity on geology, seawater chemistry and finally, on microbial life. Such an area of shallow marine hydrothermal venting is observed approximately 2.5 km east of Panarea Island (Sicily, Italy). This system is characterized by fluid temperatures of up to 135° C, gas emissions dominated by CO2 and precipitation of elemental sulfur on the seafloor. In an interdisciplinary project to investigate the influence of geofuels on marine microbiota, sediment cores and pore fluids were sampled for geological and geochemical analyses. An attempt was made to link these geochemical data with a characterization of the microbial community. One of the investigated sites (Lago Caldo, Hot Lake) is an oval-shaped (~10 by 6 meters) shallow (~2.5 m deep) depression covered by elemental sulfur. The sediments in this depression are strongly affected by hydrothermal activity: the pH of pore fluids is in a range between 5 and 6; the salinity is approximately two times higher than seawater. In situ temperatures of 36° C and 74° C (10 cm sediment depth) at two different locations within Hot Lake indicate variability in hydrothermal flux. The sediment surface layer is anoxic, and with increasing depth from the sediment-water interface, sulfate concentrations decrease from ~30 mM to less than 10 mM, whereas sulfide concentrations increase from less than 50 ?m to ~1000 ?m at 25 cm sediment depth, thus suggesting a higher potential for energy gain based on sulfur disequilibrium. As indicated by the variability in the sediment temperatures at 10 cm, fluid fluxes and mixing with seawater is not found to be uniform at Hot Lake. This is reflected in variability of the pore fluids geochemistry (anions, cations and stable isotope composition of water and sulfate) of depth profiles. DNA-fingerprinting techniques (DGGE, ARISA) revealed distinctly different bacterial 16S rRNA gene patterns for three separate sediment cores taken at Hot Lake. Intact polar lipid (IPL) biomarker analysis revealed a dominance of bacterial over archaeal biomass. The bacterial IPLs were mainly comprised of diether and diester phospholipids and ornithine lipids, indicative of viable thermophilic sulfate-reducing and acidophilic sulfide-oxidizing bacteria. Bacterial IPL abundance was highest in the sediment surface layer. Fluorescence in situ hybridization showed that with increasing depth and temperature, the abundance of archaea increased relative to that of bacteria. Comparative 16S rRNA gene analysis revealed a moderate diversity of bacteria, and a dominance of epsilonproteobacterial sequences. Cultured representatives of the detected epsilonproteobacterial classes are known to catalyze elemental sulfur reduction and oxidation reactions and to mediate the formation of iron-sulfides, including framboidal pyrite, which was found in sediment samples. We conclude that mixing between hydrothermal fluids and seawater leads to distinctly different temperature gradients and ecological niches in Hot Lake sediments. From the geochemical profiles and a preliminary characterization of the microbiological community, we found strong evidence of sulfur-related metabolism. Further investigation of certain clusters of bacteria and archaea as well as gene expression analysis will give us a deeper understanding of the interaction between geosphere and biosphere at this site in the future.

  5. Vibrio diabolicus challenge in Bathymodiolus azoricus populations from Menez Gwen and Lucky Strike hydrothermal vent sites.

    PubMed

    Martins, Eva; Santos, Ricardo Serrão; Bettencourt, Raul

    2015-12-01

    Menez Gwen (MG) and Lucky Strike (LS) deep-sea hydrothermal vents are located at 850 m and 1730 m depths respectively and support chemosynthesis-based ecosystems partially differing in heavy metal concentration, temperature range, and faunistic composition. The successfully adapted deep-sea vent mussel Bathymodiolus azoricus is found at both vent locations. In such inhospitable environments survival strategies rely on the establishment of bacteria-vent animal symbiosis In spite of the toxic nature of deep-sea vents, the problem of microbial threat and the need for immunity exist in B. azoricus. This study aims at investigating the immune system of B. azoricus from MG and LS populations by comparing immune gene expressions profiles using the deep-sea vent-related Vibrio diabolicus. Expression of nineteen immune genes was analyzed from gill, digestive gland and mantle tissues upon 3 h, 12 h and 24 h V. diabolicus challenges. Based on quantitative-Polymerase Chain Reaction (qPCR) significant gene expression differences were found among MG and LS populations and challenge times MG mussels revealed that gill and digestive gland gene expression levels were remarkably higher than those from LS mussels. Expression of Carcinolectin, Serpin-2, SRCR, IRGs, RTK, TLR2, NF-?B, HSP70 and Ferritin genes was greater in MG than LS mussels. In contrast, mantle tissue from LS mussels revealed the highest peak of expression at 24 h for most genes analyzed. The activation of immune signaling pathways demonstrated that gene expression profiles are distinct between the two mussel populations. These differences may possibly ensue from intrinsic immune transcriptional activities upon which host responses are modulated in presence of V. diabolicus. mRNA transcript variations were assessed during 24 h acclimatization taking into account the partial depuration to which mussels were subjected to. Additionally, gene expression differences may reflect still accountable effects from the presence of vent remaining microfluidic environments within the tissues analyzed. PMID:26529571

  6. Biogeographical distribution of Rimicaris exoculata resident gut epibiont communities along the Mid-Atlantic Ridge hydrothermal vent sites.

    PubMed

    Durand, Lucile; Roumagnac, Marie; Cueff-Gauchard, Valérie; Jan, Cyrielle; Guri, Mathieu; Tessier, Claire; Haond, Marine; Crassous, Philippe; Zbinden, Magali; Arnaud-Haond, Sophie; Cambon-Bonavita, Marie-Anne

    2015-10-01

    Rimicaris exoculata is a deep-sea hydrothermal vent shrimp whose enlarged gill chamber houses a complex trophic epibiotic community. Its gut harbours an autochthonous and distinct microbial community. This species dominates hydrothermal ecosystem megafauna along the Mid-Atlantic Ridge, regardless of contrasting geochemical conditions prevailing in them. Here, the resident gut epibiont community at four contrasted hydrothermal vent sites (Rainbow, TAG, Logatchev and Ashadze) was analysed and compiled with previous data to evaluate the possible influence of site location, using 16S rRNA surveys and microscopic observations (transmission electron microscopy, scanning electron microscopy and fluorescence in situ hybridization analyses). Filamentous epibionts inserted between the epithelial cell microvilli were observed on all examined samples. Results confirmed resident gut community affiliation to Deferribacteres, Mollicutes, Epsilonproteobacteria and to a lesser extent Gammaproteobacteria lineages. Still a single Deferribacteres phylotype was retrieved at all sites. Four Mollicutes-related operational taxonomic units were distinguished, one being only identified on Rainbow specimens. The topology of ribotype median-joining networks illustrated a community diversification possibly following demographic expansions, suggesting a more ancient evolutionary history and/or a larger effective population size at Rainbow. Finally, the gill chamber community distribution was also analysed through ribotype networks based on sequences from R. exoculata collected at the Rainbow, Snake Pit, TAG, Logatchev and Ashadze sites. Results allow the refining of hypotheses on the epibiont role and transmission pathways. PMID:26324855

  7. Three-Dimensional Slowness Images of the Upper Crust Beneath the Lucky Strike Hydrothermal Vent Sites

    NASA Astrophysics Data System (ADS)

    Seher, T.; Crawford, W.; Singh, S.; Canales, J. P.; Combier, V.; Cannat, M.; Carton, H.; Dusunur, D.; Escartin, J.; Miranda, M. J.; Pouillet-Erguy, A.

    2005-12-01

    In June-July 2005 we carried out the SISMOMAR cruise, as part of the MOMAR project (Monitoring the Mid-Atlantic Ridge). Within this cruise, we conducted a 3D seismic reflection survey over an 18 km km x 3.8 km area covering both the Lucky Strike volcano and hydrothermal vents field. In order to have a full coverage inside the 3D box, shots continued for 2.25 km on either side of the box and extended out to the median valley bounding faults. To complement the streamer measurements 25 Ocean Bottom Seismometers (OBS) were placed in an 18 km x 18 km area. 11 OBS positions lie inside the 3D box and can be used to determine a very detailed image of the 3D velocity structure beneath the Lucky Strike volcano and hydrothermal vents field. For the 3D box a tuned array of 14 air guns (2600 cubic inches) was fired at an interval of 37.5 m for a total of 39 lines. We will present the first results of the OBS measurements near the Lucky Strike volcano. As a first step towards a joint 3D travel time and slowness (the inverse of velocity at turning depth) tomography, we present the 3D slowness function (latitude, longitude, offset), which can be considered as a 3D brute stack velocity image of the sub-surface (c.f. Barton and Edwards, 1999). The presence of fluid in the upper crust due to hydrothermal circulation should appear as a low velocity anomaly beneath the hydrothermal vents. In the next step the OBS measurements will be used to corroborate the reflection images of layer 2A observed in the streamer data for the 3D box. The OBS inside the 3D box recorded turning ray arrivals from the upper crust at a very fine sampling interval (37.5 m x 100 m) over a large azimuth. This provides the unique opportunity for jointly inverting travel time and slowness. Hence the measurements contain information on local gradients and should provide a very detailed velocity model of the subsurface, including information on hydrothermal systems and a possilbe anisotropy (e.g. Cherret and Singh, 1999). References: P. Barton, R. Edwards: Velocity imaging by tau-p transformation, LITHOS Science Report, 1999, 1, 67-75. A. Cherrett, S. Singh: 3D anisotropic models from multi-component data, LITHOS Science Report, 1999, 1, 29-34.

  8. Hydrothermal vent complexes associated with sill intrusionsin sedimentarybasins

    E-print Network

    Podladchikov, Yuri

    Hydrothermal vent complexes associated with sill intrusionsin sedimentarybasins BJIbRNJAMTVEIT1 sedimentarybasinscause strongthermal perturbations and frequentlycause extensivehydrothermalactivity.Hydrothermal vent strata surrounding a central vent complex. comprisingmultiplesandstone dykes, pipes, and hydrothermal

  9. Living with the Heat. Submarine Ring of Fire--Grades 5-6. Hydrothermal Vent Ecology.

    ERIC Educational Resources Information Center

    National Oceanic and Atmospheric Administration (DOC), Rockville, MD.

    This activity is designed to teach about hydrothermal vent ecology. Students are expected to describe how hydrothermal vents are formed and characterize the physical conditions at these sites, explain chemosynthesis and contrast this process with photosynthesis, identify autotrophic bacteria as the basis for food webs in hydrothermal vent

  10. The NeMO Explorer Web Site: Interactive Exploration of a Recent Submarine Eruption and Hydrothermal Vents, Axial Volcano, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Weiland, C.; Chadwick, W. W.; Embley, R. W.

    2001-12-01

    To help visualize the submarine volcanic landscape at NOAA's New Millennium Observatory (NeMO), we have created the NeMO Explorer web site: http://www.pmel.noaa.gov/vents/nemo/explorer.html. This web site takes visitors a mile down beneath the ocean surface to explore Axial Seamount, an active submarine volcano 300 miles off the Oregon coast. We use virtual reality to put visitors in a photorealistic 3-D model of the seafloor that lets them view hydrothermal vents and fresh lava flows as if they were really on the seafloor. At each of six virtual sites there is an animated tour and a 360o panorama in which users can view the volcanic landscape and see biological communities within a spatially accurate context. From the six sites there are hyperlinks to 50 video clips taken by a remotely operated vehicle. Each virtual site concentrates on a different topic, including the dynamics of the 1998 eruption at Axial volcano (Rumbleometer), high-temperature hydrothermal vents (CASM and ASHES), diffuse hydrothermal venting (Marker33), subsurface microbial blooms (The Pit), and the boundary between old and new lavas (Castle vent). In addition to exploring the region geographically, visitors can also explore the web site via geological concepts. The concepts gallery lets you quickly find information about mid-ocean ridges, hydrothermal vents, vent fauna, lava morphology, and more. Of particular interest is an animation of the January 1998 eruption, which shows the rapid inflation (by over 3 m) and draining of the sheet flow. For more info see Fox et al., Nature, v.412, p.727, 2001. This project was funded by NOAA's High Performance Computing and Communication (HPCC) and Vents Programs. Our goal is to present a representative portion of the vast collection of NOAA's multimedia imagery to the public in a way that is easy to use and understand. These data are particularly challenging to present because of their high data rates and low contextual information. The 3-D models create effective context and new video technology allows us to present good quality video at lower data rates. Related curriculum materials for middle- and high-school students are also available from the NeMO web site at http://www.pmel.noaa.gov/vents/nemo/education.html. >http://www.pmel.noaa.gov/vents/nemo/explorer.html

  11. The Discovery of New Deep-Sea Hydrothermal Vent Communities in the Southern Ocean and Implications for

    E-print Network

    Naveira Garabato, Alberto

    The Discovery of New Deep-Sea Hydrothermal Vent Communities in the Southern Ocean and Implications discovery of deep-sea hydrothermal vents along the Gala´pagos Rift in 1977, numerous vent sites and endemic deep-sea fauna. It has also been proposed as a gateway connecting hydrothermal vents in different

  12. Trophic regions of a hydrothermal plume dispersing away from an ultramafic-hosted vent-system: Von Damm vent-site, Mid-Cayman Rise

    NASA Astrophysics Data System (ADS)

    Bennett, Sarah A.; Coleman, Max; Huber, Julie A.; Reddington, Emily; Kinsey, James C.; McIntyre, Cameron; Seewald, Jeffrey S.; German, Christopher R.

    2013-02-01

    Abstract Deep-sea ultramafic-hosted <span class="hlt">vent</span> systems have the potential to provide large amounts of metabolic energy to both autotrophic and heterotrophic microorganisms in their dispersing <span class="hlt">hydrothermal</span> plumes. Such <span class="hlt">vent</span>-systems release large quantities of hydrogen and methane to the water column, both of which can be exploited by autotrophic microorganisms. Carbon cycling in these <span class="hlt">hydrothermal</span> plumes may, therefore, have an important influence on open-ocean biogeochemistry. In this study, we investigated an ultramafic-hosted system on the Mid-Cayman Rise, emitting metal-poor and hydrogen sulfide-, methane-, and hydrogen-rich <span class="hlt">hydrothermal</span> fluids. Total organic carbon concentrations in the plume ranged between 42.1 and 51.1 ?M (background = 43.2 ± 0.7 ?M (n = 5)) and near-field plume samples with elevated methane concentrations imply the presence of chemoautotrophic primary production and in particular methanotrophy. In parts of the plume characterized by persistent potential temperature anomalies but lacking elevated methane concentrations, we found elevated organic carbon concentrations of up to 51.1 ?M, most likely resulting from the presence of heterotrophic communities, their extracellular products and <span class="hlt">vent</span> larvae. Elevated carbon concentrations up to 47.4 ?M were detected even in far-field plume samples. Within the Von Damm <span class="hlt">hydrothermal</span> plume, we have used our data to hypothesize a microbial food web in which chemoautotrophy supports a heterotrophic community of microorganisms. Such an active microbial food web would provide a source of labile organic carbon to the deep ocean that should be considered in any future studies evaluating sources and sinks of carbon from <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> to the deep ocean.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3250503','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3250503"><span id="translatedtitle">Antarctic Marine Biodiversity and Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chown, Steven L.</p> <p>2012-01-01</p> <p>The diversity of many marine benthic groups is unlike that of most other taxa. Rather than declining from the tropics to the poles, much of the benthos shows high diversity in the Southern Ocean. Moreover, many species are unique to the Antarctic region. Recent work has shown that this is also true of the communities of Antarctic deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. <span class="hlt">Vent</span> ecosystems have been documented from many <span class="hlt">sites</span> across the globe, associated with the thermally and chemically variable habitats found around these, typically high temperature, streams that are rich in reduced compounds and polymetallic sulphides. The animal communities of the East Scotia Ridge <span class="hlt">vent</span> ecosystems are very different to those elsewhere, though the microbiota, which form the basis of <span class="hlt">vent</span> food webs, show less differentiation. Much of the biological significance of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> lies in their biodiversity, the diverse biochemistry of their bacteria, the remarkable symbioses among many of the marine animals and these bacteria, and the prospects that investigations of these systems hold for understanding the conditions that may have led to the first appearance of life. The discovery of diverse and unusual Antarctic <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystems provides opportunities for new understanding in these fields. Moreover, the Antarctic <span class="hlt">vents</span> south of 60°S benefit from automatic conservation under the Convention on the Conservation of Antarctic Marine Living Resources and the Antarctic Treaty. Other deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> located in international waters are not protected and may be threatened by growing interests in deep-sea mining. PMID:22235192</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.people.fas.harvard.edu/~langmuir/Papers/Langmuir%20EPSL%2097.pdf','EPRINT'); return false;" href="http://www.people.fas.harvard.edu/~langmuir/Papers/Langmuir%20EPSL%2097.pdf"><span id="translatedtitle">ELSEVIER Earth and Planetary Science Letters 148 (1997) 69-9 I <span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> near a mantle hot spot: the Lucky Strike <span class="hlt">vent</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Langmuir, Charles H.</p> <p>1997-01-01</p> <p>EPSL ELSEVIER Earth and Planetary Science Letters 148 (1997) 69-9 I <span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> near <span class="hlt">site</span> found on crust that is dominated by a hot spot signature. Multiple <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> occur over that the <span class="hlt">hydrothermal</span> system has a long history and may have recently been rejuvenated. Fauna at the Lucky Strike <span class="hlt">vent</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMOS11A0350S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMOS11A0350S"><span id="translatedtitle">Time Series Studies of Faunal Colonization and Temperature Variations at Diffuse-Flow <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> <span class="hlt">Sites</span> Near 9° 50'N, EPR</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shank, T. M.; Scheirer, D.; Fornari, D. J.</p> <p>2001-12-01</p> <p>The April 1991 discovery of newly-formed <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in areas of intense volcanic activity along the East Pacific Rise (EPR) between 9\\deg 45' and 9\\deg 52'N provided a unique opportunity to follow temporal changes in biological community structure and <span class="hlt">vent</span> fluid temperature and chemistry since the birth of numerous deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Discrete high resolution biological imaging and fluid chemistry samples have been collected in conjunction with autonomous temperature probe arrays that have monitored the fluid temperature at 10-15 minute intervals since 1993, within four diffuse-flow regions of the BioTransect at 9\\deg 50'N on the EPR. During ~1 year deployments between 1993 and 2000, active <span class="hlt">vent</span> invertebrate colonization by greater than 500 individuals (representing 8 species) occurred on more than 60 recovered temperature probes comprising 12 arrays. On each temperature probe, the position and length of individual organisms were mapped to correlate the position of settlement and growth rates with the environmental temperatures experienced by these colonists. Regressions of colonization parameters with temperature measures (such as average, minimum, and maximum T) from multiple communities, along with size-frequency histograms and growth rates, indicate that the abundance of the vestimentiferan Tevnia jerichonana was greater than Riftia pachyptila tube worms and bathymodiolid mussels on temperature probes bathed in significantly higher average and maximum temperatures. Results strongly suggest that Tevnia has a greater physiological tolerance to higher temperatures and elevated geochemical concentrations (e.g., sulfide species) than Riftia and mussels. Significant differential colonization onto probes within an array demonstrates thermal and chemical habitat preferences by vestimentiferan tubeworms and mussels. Thus, patterns of active faunal colonization in <span class="hlt">hydrothermal</span> areas vary with differing temperature regimes and associated environmental conditions. Spectral analysis of the temperature probe data in diffuse-flow <span class="hlt">vent</span> <span class="hlt">sites</span> indicate that variations in the <span class="hlt">hydrothermal</span> fluid temperature experienced by <span class="hlt">vent</span> fauna are influenced by: (1) tidal and primary <span class="hlt">vent</span> flux oscillations, (2) microhabitat structure associated with different patterns of community development, and (3) geological parameters, such as local geological setting, local and regional crustal permeability, and proximity to high-temperature <span class="hlt">venting</span>. The spectral character of the measured temperature fluctuations varies significantly over distance scales of tens of centimeters and greater, from the center of a diffuse-flow field to its edges and from the seafloor upwards. Correlation with predicted tidal variations and measured currents, for parts of the temperature records, indicate an important, but not exclusive, tidal component governing the temperature variations. Significant fluctuations in temperature occur at periods different from tidal periods and their harmonics. Thus, local geological and biological structures and processes are key elements to understanding the physical and ecological changes in this dynamic environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21232364','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21232364"><span id="translatedtitle">Biogeography of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> communities along seafloor spreading centers.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Van Dover, C L</p> <p>1990-08-01</p> <p>Compared to terrestrial and shallow-water habitats, deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are unique environments characterized by their local insularity, global distribution, individual ephemerality, collective geological longevity, geochemical homogeneity, and their physical and energetic isolation from the catastrophic events implicated in the extinction and speciation of terrestrial and shallow-water forms. Development of <span class="hlt">vent</span> communities has thus occurred in novel biogeographical contexts that challenge our ability to understand evolutionary processes in the deep sea. Recent field work by French, Canadian, German, Japanese and American scientists has revealed intriguing patterns in the taxonomic composition and distribution of <span class="hlt">vent</span> organisms at geographically disjunct study <span class="hlt">sites</span>. PMID:21232364</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.cs.bham.ac.uk/~nah/bibtex/papers/Saigol2010.pdf','EPRINT'); return false;" href="http://www.cs.bham.ac.uk/~nah/bibtex/papers/Saigol2010.pdf"><span id="translatedtitle">Belief Change Maximisation for <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Hunting Using Occupancy Grids</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Wyatt, Jeremy</p> <p></p> <p>Belief Change Maximisation for <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Hunting Using Occupancy Grids Zeyn Saigol floor for <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. The state of the art in these problems is information lookahead Vehicle (AUV) prospecting for <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, which are superheated outgassings of water found on mid</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://noblegaslab.coas.oregonstate.edu/people/graham/publications/Edmonds2003.pdf','EPRINT'); return false;" href="http://noblegaslab.coas.oregonstate.edu/people/graham/publications/Edmonds2003.pdf"><span id="translatedtitle">Discovery of abundant <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> on the ultraslow-spreading</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Graham, David W.</p> <p></p> <p>............................................................................................................................................................................. Submarine <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> along mid-ocean ridges is an important contributor to ridge thermal structure predicted that the incidence of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> would be extremely low on ultraslow-spreading ridgesPublishing Group #12;active <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> on the Gakkel ridge, which is the slowest spreading (0.6­1.3 cm yr</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013BGD....10.2013B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013BGD....10.2013B"><span id="translatedtitle">Differential gene expression in the mussel Bathymodiolus azoricus from the Menez Gwen and Lucky Strike deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bettencourt, R.; Rodrigues, M. I.; Barros, I.; Cerqueira, T.; Freitas, C.; Costa, V.; Pinheiro, M.; Egas, C.; Santos, R. S.</p> <p>2013-02-01</p> <p>The deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel Bathymodiolus azoricus is a symbiont bearing bivalve that is found in great abundance at the Menez Gwen and Lucky Strike <span class="hlt">vent</span> <span class="hlt">sites</span> and in close vicinity off the Azores region near the Mid-Atlantic Ridge (MAR). The distinct relationships that <span class="hlt">vent</span> mussels have developed with their physical and chemical environments are likely reflected in global gene expression profiles providing thus a means to distinguish geographically distinct <span class="hlt">vent</span> mussels on the basis of gene expression studies, fluorescence in situ hybridization (FISH) experiments and 16S rRNA amplicon sequencing, to assess the natural expression of bacterial genes and <span class="hlt">vent</span> mussel immune genes and the constitutive distribution and relative abundance of endosymbiotic bacteria within gill tissues. Our results confirmed the presence of methanotroph-related endosymbionts in Menez Gwen <span class="hlt">vent</span> mussels whereas Lucky Strike specimens seem to harbor a different bacterial morphotype when a methane monooxygenase gene specific probe was used. No qualitative differences could be visualized between Menez Gwen and Lucky Strike individuals when tested with sulfur-oxidizing-related nucleic-acid probe. Quantitative PCR (qPCR) studies revealed varied gene expression profiles in both Menez Gwen and Lucky Strike mussel gill tissues for the immune genes selected. Genes encoding transcription factors presented noticeably low levels of fold expression whether in MG or LS animals whereas the genes encoding effector molecules appeared to have higher levels expression in MG gill tissues. The peptidoglycan recognition molecule, encoding gene, PGRP presented the highest level of transcriptional activity among the genes analyzed in MG gill tissues, seconded by carcinolectin and thus denoting the relevance of immune recognition molecules in early stage of the immune responses onset. Genes regarded as encoding molecules involved in signaling pathways were consistently expressed in both MG and LS gill tissues. Remarkably, the immunity-related GTPase encoding gene demonstrated in LS samples, the highest level of expression among the signaling molecule encoding genes tested when expressions levels were compared between MG and LG animals. A differential expression analysis of bacterial genes between MG and LS indicated a clear expression signature in LS gill tissues. The bacterial community structure ensued from the 16S rRNA sequencing analyses pointed at a unpredicted conservation of endosymbiont bacterial loads between MG and LS samples. Taken together, our results support the premise that Bathymodiolus azoricus exhibits different transcriptional statuses depending on which <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">site</span> it is collected from and within the same collection <span class="hlt">site</span> while exhibiting differential levels of expression of genes corresponding to different immune functional categories. The present study represents a first attempt to characterize gene expression signatures in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> animals issued from distinct deep-sea environmental <span class="hlt">sites</span> based on immune and bacterial genes expressions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16199029','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16199029"><span id="translatedtitle">Biological factors influencing tissue compartmentalization of trace metals in the deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> bivalve Bathymodiolus azoricus at geochemically distinct <span class="hlt">vent</span> <span class="hlt">sites</span> of the Mid-Atlantic Ridge.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kádár, Enikõ; Santos, Ricardo S; Powell, Jonathan J</p> <p>2006-06-01</p> <p>In this study, we investigated on concentrations of trace metals (Al, Cd, Mn, Co, and Hg) in the <span class="hlt">hydrothermal</span> bivalve Bathymodiolus azoricus, a dominant species at most <span class="hlt">vent</span> <span class="hlt">sites</span> along the Mid-Atlantic Ridge (MAR), and in its endosymbiont bacteria and commensal parasite Branchipolynoe seepensis. Comparison of our results with data from the literature on non-<span class="hlt">hydrothermal</span> bivalves suggests lack of "extreme" uptake of trace metals by B. azoricus, except for Hg concentration which exceeded manyfold previously reported values. Mussels collected from three geochemically distinct <span class="hlt">vent</span> <span class="hlt">sites</span>, Menez Gwen, Lucky Strike, and Rainbow, along the MAR showed significant differences in tissue concentration of metals. Proportionality of metals in soft tissues of mussels reflected variation of water chemistry at different <span class="hlt">vents</span>, which in turn conserved the order of trace metal prevalence in undiluted fluids. There were significant tissue-specific differences in trace metal compartmentalization for all metals investigated. Byssus thread contained the highest metal concentration among examined tissues, and thus it is suggested to be an important detoxification route. Size-dependent differences in metal concentrations were detected only for Hg, revealing a general trend of small mussels accumulating more metal than big mussels. Endosymbiont bacteria are shown to exclusively sequester Al from the host gill and contribute to removal of other toxic metals in mussels from Menez Gwen. The commensal parasite present in all mussels from Lucky Strike had higher tissue concentrations of Mn, Al, and Co than the host gill, unlike Cd and Hg which were considerably lower in the former, and thus its role in detoxification remains unclear. Bioaccumulation potential of <span class="hlt">vent</span> bivalves and associated organisms are quantified as concentration factors and compared to make inferences on the putative role of the endosymbiont bacteria and the commensal parasite in detoxification of trace metals. PMID:16199029</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li class="active"><span>1</span></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_1 --> <div id="page_2" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active"><span>2</span></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="21"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040065937&hterms=Hydrothermal+vents&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2528Hydrothermal%2Bvents%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040065937&hterms=Hydrothermal+vents&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2528Hydrothermal%2Bvents%2529"><span id="translatedtitle">Optical Detection of Organic Chemical Biosignatures at <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Conrad, P. G.; Lane, A. L.; Bhartia, R.; Hug, W. H.</p> <p>2004-01-01</p> <p>We have developed a non-contact, optical life detection instrument that can detect organic chemical biosignatures in a number of different environments, including dry land, shallow aqueous, deep marine or in ice. Hence, the instrument is appropriate as a biosignature survey tool both for Mars exploration or in situ experiments in an ice-covered ocean such as one might wish to explore on Europa. Here, we report the results we obtained on an expedition aboard the Russian oceanographic vessel Akademik Mstislav Keldysh to <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> in the Pacific Ocean using our life detection instrument MCDUVE, a multichannel, deep ultraviolet excitation fluorescence detector. MCDUVE detected organic material distribution on rocks near the <span class="hlt">vent</span>, as well as direct detection of organisms, both microbial and microscopic. We also were able to detect organic material issuing directly from <span class="hlt">vent</span> chimneys, measure the organic signature of the water column as we ascended, and passively observe the emission of light directly from some <span class="hlt">vents</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www4.ncsu.edu/~drbohnen/MG_NCSU/Publications_files/2001JB000651.pdf','EPRINT'); return false;" href="http://www4.ncsu.edu/~drbohnen/MG_NCSU/Publications_files/2001JB000651.pdf"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">venting</span> along Earth's fastest spreading center: East Pacific Rise,</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Bohnenstiehl, Delwayne</p> <p></p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">venting</span> along Earth's fastest spreading center: East Pacific Rise, 27.5°­32.3°S E. T by a <span class="hlt">hydrothermal</span> plume. Plume chemistry mostly reflected discharge from mature <span class="hlt">vent</span> fields apparently unperturbed March/April 1998 we conducted detailed mapping and sampling of <span class="hlt">hydrothermal</span> plumes along six segments</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dspace.mit.edu/handle/1721.1/45148','EPRINT'); return false;" href="http://dspace.mit.edu/handle/1721.1/45148"><span id="translatedtitle">Spatial and temporal population genetics at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> along the East Pacific Rise and Galápagos Rift</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Fusaro, Abigail Jean</p> <p>2008-01-01</p> <p>Ecological processes at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on fast-spreading mid-ocean ridges are punctuated by frequent physical disturbance. Larval dispersal among disjunct <span class="hlt">vent</span> <span class="hlt">sites</span> facilitates the persistence of sessile ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5815304','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5815304"><span id="translatedtitle">Ecology of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> communities: A review</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lutz, R.A.; Kennish, M.J. )</p> <p>1993-08-01</p> <p>The present article reviews studies of the past 15 years of active and inactive <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. The focus of the discussion is on the ecology of the biological communities inhabiting <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. These communities exhibit high densities and biomass, low species diversity, rapid growth rates, and high metabolic rates. The authors attempt to relate the biology of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems to geology. Future directions for <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> research are suggested. Since many <span class="hlt">vent</span> populations are dependent on <span class="hlt">hydrothermal</span> fluids and are consequently unstable, both short- and long-term aspects of the ecology of the <span class="hlt">vent</span> organisms and the influence of chemical and geological factors on the biology of <span class="hlt">vent</span> systems need to be established. 200 refs., 28 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5247351','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5247351"><span id="translatedtitle">Diffuse flow from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Doctoral thesis</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Trivett, D.A.</p> <p>1991-08-01</p> <p>The effluent from a collection of diffuse <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> was modelled to determine the fate of the source of flow under typical environmental conditions at seafloor spreading centers. A laboratory simulation was conducted to test an analytic model of diffuse plume rise. The results showed that diffuse plumes are likely to remain near the seafloor, with their maximum rise height scaled with the diameter of the source of diffuse flow. The entrainment of ambient seawater into these plumes is limited by the proximity to the seafloor, thus slowing the rate of dilution. The model of diffuse plume behaviour was used to guide the design and implementation of a scheme for monitoring the flow from diffuse <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the ocean. A deployment of an array at the Southern Juan de Fuca Ridge yielded measurements of a variety of diffuse plume properties, including total heat output. Two distinct sources of <span class="hlt">hydrothermal</span> flow were detected during the field deployment. The larger source was 1-1.5km north of the instrument array, and its energy output was 450 + or - 270MW. A smaller source was located 100m east of one instrument in the array. The energy output of the source was 12 + or - 8MW. The rise heights of the centerlines of these plumes were 45m and 10m, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/543373','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/543373"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> is Lake Tanganyika, East African Rift system</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tiercelin, J.J.; Pflumio, C.; Castrec, M.</p> <p>1993-06-01</p> <p>Sublacustrine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> with associated massive sulfides were discovered during April 1987 at Pemba and Cape Banza on the Zaire side of the northern basin of Lake Tanganyika, East African Rift system. New investigations by a team of ten scuba divers during the multinational (France, Zaire, Germany, and Burundi) TANGANYDRO expedition (August-October 1991) found <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> down to a depth of 46 m along north-trending active faults bounding the Tanganyika rift on the western side. Temperatures from 53 to 103 {degrees}C were measured in <span class="hlt">hydrothermal</span> fluids and sediments. Veins of massive sulfides 1-10 cm thick (pyrite and marcasite banding) were found associated with <span class="hlt">vents</span> at the Pemba <span class="hlt">site</span>. At Cape Banza, active <span class="hlt">vents</span> are characterized by 1-70-cm-high aragonite chimneys, and there are microcrystalline pyrite coatings on the walls of <span class="hlt">hydrothermal</span> pipes. <span class="hlt">Hydrothermal</span> fluid end members show distinctive compositions at the two <span class="hlt">sites</span>. The Pemba end member is a NaHCO{sub 3}-enriched fluid similar to the NaHCO{sub 3} thermal fluids form lakes Magadi and Bogoria in the eastern branch of the rift. The Cape Banza end member is a solution enriched in NaCl. Such brines may have a deep-seated basement origin, as do the Uvinza NaCl brines on the eastern flank of the Tanganyika basin. Geothermometric calculations have yielded temperatures of fluid-rock interaction of 219 and 179 {degrees}C in the Pemba and Cape Banza systems, respectively. Abundant white or reddish-brown microbial colonies resembling Beggiatoa mats were found surrounding the active <span class="hlt">vents</span>. Thermal fluid circulation is permitted by opening of cracks related to 130{degrees}N normal-dextral faults that intersect the north-south major rift trend. The sources of heat for such <span class="hlt">hydrothermal</span> systems may relate to the existence of magmatic bodies under the rift, which is suggested by the isotopic composition of carbon dioxide released at Pemba and Cape Banza. 21 refs., 2 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004GMS...148..245B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004GMS...148..245B"><span id="translatedtitle">On the global distribution of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baker, Edward T.; German, Christopher R.</p> <p></p> <p>The "magmatic budget hypothesis" proposes that variability in magma supply is the primary control on the large-scale <span class="hlt">hydrothermal</span> distribution pattern along oceanic spreading ridges. The concept is simple but several factors make testing the hypothesis complex: scant <span class="hlt">hydrothermal</span> flux measurements, temporal lags between magmatic and <span class="hlt">hydrothermal</span> processes, the role of permeability, nonmagmatic heat sources, and the uncertainties of <span class="hlt">vent</span>-field exploration. Here we examine this hypothesis by summarizing our current state of knowledge of the global distribution of active <span class="hlt">vent</span> fields, which presently number ˜280, roughly a quarter of our predicted population of ˜1000. Approximately 20% of the global ridge system has now been surveyed at least cursorily for active <span class="hlt">sites</span>, but only half that length has been studied in sufficient detail for statistical treatment. Using 11 ridge sections totaling 6140 km we find a robust linear correlation between either <span class="hlt">site</span> frequency or <span class="hlt">hydrothermal</span> plume incidence and the magmatic budget estimated from crustal thickness. These trends cover spreading rates of 10-150 mm/yr and strongly support the magma budget hypothesis. A secondary control, permeability, may become increasingly important as spreading rates decrease and deep faults mine supplemental heat from direct cooling of the upper mantle, cooling gabbroic intrusions, and serpentinization of underlying ultramafics. Preliminary observations and theory suggest that <span class="hlt">hydrothermal</span> activity on hotspot-affected ridges is relatively deficient, although paucity of data precludes generalizing this result. While the fullness of our conclusions depends upon further detailed study of <span class="hlt">vent</span> field frequency, especially on slow-spreading ridges, they are consistent with global distributions of deep-ocean 3He, an unequivocally magmatic tracer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.B51D0404T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.B51D0404T"><span id="translatedtitle">Raman Spectroscopy at Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thompson, W. J.; Marquardt, B. J.; Lilley, M. D.</p> <p>2008-12-01</p> <p>In this presentation we will describe the development and optimization of a custom submersible Raman instrument that was successfully deployed in one of the harshest environments on the planet, <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems. The primary objective of this project was to develop a multi-platform, broad spectral chemical sensor for investigating <span class="hlt">hydrothermal</span> processes in the deep ocean. Mid-ocean ridge <span class="hlt">hydrothermal</span> systems are complex and highly variable with extreme thermal and chemical gradients which support a diverse ecosystem of micro and macro fauna, specially adapted to thrive within variable mixtures of <span class="hlt">hydrothermal</span> fluid and seawater. <span class="hlt">Hydrothermal</span> inputs have large effects on global geochemical cycles yet our understanding of the temporal variability of these contributions to the ocean needs to be further investigated. Towards this goal a sensitive, in situ Raman spectroscopy instrument was developed for extended geochemical analysis of <span class="hlt">hydrothermal</span> systems. Raman spectroscopy is a highly selective, full spectral optical technique capable of non-invasively identifying and quantifying numerous organic and inorganic species in a deep ocean environment. Advantages of Raman spectroscopy for in situ analysis include broad spectral range, no sample preparation and fast analysis times. The Raman instrument developed was designed to maximize sensitivity and spectral breadth to ensure identification and quantification of a vast array of geochemical species in the deep. The custom high resolution, high sensitivity Raman instrument is fiber-optically coupled to a high temperature and pressure Raman Ballprobe immersion optic. This novel probe is designed to accurately collect Raman data from turbulent and opaque samples at high temperatures and pressures. This instrument was successfully deployed by DSV/Alvin to numerous diffuse and high temperature <span class="hlt">vent</span> <span class="hlt">sites</span> at the Main Endeavour Field of the Juan de Fuca Ridge. A variety of <span class="hlt">vents</span> were sampled and we present the first qualitative Raman spectra of chemical species in actively <span class="hlt">venting</span> fluid. Currently we are seeking to fully identify and quantitate the chemical species in both diffuse and high temperature <span class="hlt">vent</span> Raman data, optimize algorithms to maintain calibration in this extreme environment and redesign the instrument for multiple month deployment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://xraysweb.lbl.gov/uxas/Publicatons/Papers/pdfs/ismej201148a.pdf','EPRINT'); return false;" href="http://xraysweb.lbl.gov/uxas/Publicatons/Papers/pdfs/ismej201148a.pdf"><span id="translatedtitle">ORIGINAL ARTICLE Ultra-diffuse <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> supports</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p></p> <p></p> <p>ORIGINAL ARTICLE Ultra-diffuse <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> supports Fe-oxidizing bacteria and massive University, Bellingham, WA, USA A novel <span class="hlt">hydrothermal</span> field has been discovered at the base of Lo¯ihi Seamount seawater temperature, derives from a distal, ultra-diffuse <span class="hlt">hydrothermal</span> source. FeMO Deep is expressed</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009DSRII..56.1577E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009DSRII..56.1577E"><span id="translatedtitle">Evidence for a chemoautotrophically based food web at inactive <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> (Manus Basin)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Erickson, K. L.; Macko, S. A.; Van Dover, C. L.</p> <p>2009-09-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> are ephemeral systems. When <span class="hlt">venting</span> shuts down, sulfide-dependent taxa die off, and non-<span class="hlt">vent</span> taxa can colonize the hard substrata. In Manus Basin (Papua New Guinea), where <span class="hlt">hydrothermally</span> active and inactive <span class="hlt">sites</span> are interspersed, hydroids, cladorhizid sponges, barnacles, bamboo corals, and other invertebrate types may occupy inactive <span class="hlt">sites</span>. Carbon and nitrogen isotopic compositions of animals occupying inactive <span class="hlt">sites</span> are consistent with nutritional dependence on either chemoautotrophically or photosynthetically produced organic material, but sulfur isotopic compositions of these animals point to a chemoautotrophic source of sulfur from dissolved sulfide in <span class="hlt">vent</span> fluids rather than sulfur derived from seawater sulfate through photosynthesis. Given that suspension-feeding and micro-carnivorous invertebrates are the biomass dominants at inactive <span class="hlt">sites</span>, the primary source of chemoautotrophic nutrition is likely suspended particulates and organisms delivered from nearby active <span class="hlt">vents</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12529639','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12529639"><span id="translatedtitle">Discovery of abundant <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> on the ultraslow-spreading Gakkel ridge in the Arctic Ocean.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Edmonds, H N; Michael, P J; Baker, E T; Connelly, D P; Snow, J E; Langmuir, C H; Dick, H J B; Mühe, R; German, C R; Graham, D W</p> <p>2003-01-16</p> <p>Submarine <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> along mid-ocean ridges is an important contributor to ridge thermal structure, and the global distribution of such <span class="hlt">vents</span> has implications for heat and mass fluxes from the Earth's crust and mantle and for the biogeography of <span class="hlt">vent</span>-endemic organisms. Previous studies have predicted that the incidence of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> would be extremely low on ultraslow-spreading ridges (ridges with full spreading rates <2 cm x yr(-1)-which make up 25 per cent of the global ridge length), and that such <span class="hlt">vent</span> systems would be hosted in ultramafic in addition to volcanic rocks. Here we present evidence for active <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> on the Gakkel ridge, which is the slowest spreading (0.6-1.3 cm x yr(-1)) and least explored mid-ocean ridge. On the basis of water column profiles of light scattering, temperature and manganese concentration along 1,100 km of the rift valley, we identify <span class="hlt">hydrothermal</span> plumes dispersing from at least nine to twelve discrete <span class="hlt">vent</span> <span class="hlt">sites</span>. Our discovery of such abundant <span class="hlt">venting</span>, and its apparent localization near volcanic centres, requires a reassessment of the geologic conditions that control <span class="hlt">hydrothermal</span> circulation on ultraslow-spreading ridges. PMID:12529639</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.V23A2385I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.V23A2385I"><span id="translatedtitle">Geomicrobiology of <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> in Yellowstone Lake: Phylogenetic and Functional Analysis suggest Importance of Geochemistry (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Inskeep, W. P.; Macur, R.; Jay, Z.; Clingenpeel, S.; Tenney, A.; Lavalvo, D.; Shanks, W. C.; McDermott, T.; Kan, J.; Gorby, Y.; Morgan, L. A.; Yooseph, S.; Varley, J.; Nealson, K.</p> <p>2010-12-01</p> <p>Yellowstone Lake (Yellowstone National Park, WY, USA) is a large, high-altitude, fresh-water lake that straddles the most recent Yellowstone caldera, and is situated on top of significant <span class="hlt">hydrothermal</span> activity. An interdisciplinary study is underway to evaluate the geochemical and geomicrobiological characteristics of several <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments sampled using a remotely operated vehicle, and to determine the degree to which these <span class="hlt">vents</span> may influence the biology of this young freshwater ecosystem. Approximately six different <span class="hlt">vent</span> systems (locations) were sampled during 2007 and 2008, and included water obtained directly from the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> as well as biomass and sediment associated with these high-temperature environments. Thorough geochemical analysis of these <span class="hlt">hydrothermal</span> environments reveals variation in pH, sulfide, hydrogen and other potential electron donors that may drive primary productivity. The concentrations of dissolved hydrogen and sulfide were extremely high in numerous <span class="hlt">vents</span> sampled, especially the deeper (30-50 m) <span class="hlt">vents</span> located in the Inflated Plain, West Thumb, and Mary Bay. Significant dilution of <span class="hlt">hydrothermal</span> fluids occurs due to mixing with surrounding lake water. Despite this, the temperatures observed in many of these <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> range from 50-90 C, and elevated concentrations of constituents typically associated with geothermal activity in Yellowstone are observed in waters sampled directly from <span class="hlt">vent</span> discharge. Microorganisms associated with elemental sulfur mats and filamentous ‘streamer’ communities of Inflated Plain and West Thumb (pH range 5-6) were dominated by members of the deeply-rooted bacterial Order Aquificales, but also contain thermophilic members of the domain Archaea. Assembly of metagenome sequence from the Inflated Plain <span class="hlt">vent</span> biomass and to a lesser extent, West Thumb <span class="hlt">vent</span> biomass reveal the importance of Sulfurihydrogenibium-like organisms, also important in numerous terrestrial geothermal outflow channels of YNP. Analysis of functional genes present in the consensus metagenome sequence representing these populations indicate metabolic potential for oxidation of reduced sulfur and hydrogen, both of which are present at high concentrations in these <span class="hlt">vent</span> ecosystems. Metagenome sequence of biomass associated with sediments from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> at Mary Bay (50 m depth) suggest greater archaeal and bacterial diversity in this environment, which may be due to higher concentrations of hydrogen, iron, and manganese measured in these environments. Results from metagenome sequence and modest 16S rRNA gene surveys from <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> biomass indicate that several groups of novel thermophilic archaea inhabit these <span class="hlt">sites</span>, and in many cases, are represented by organisms not found in YNP terrestrial geothermal environments that have been characterized to date. The <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> from Inflated Plain and West Thumb indicate a linkage between various geochemical attributes (sulfide, hydrogen) and the metabolic potential associated with dominant Aquificales populations present in these communities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080047210','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080047210"><span id="translatedtitle">Deep-Sea <span class="hlt">Hydrothermal-Vent</span> Sampler</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Behar, Alberto E.; Venkateswaran, Kasthur; Matthews, Jaret B.</p> <p>2008-01-01</p> <p>An apparatus is being developed for sampling water for signs of microbial life in an ocean <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> at a depth of as much as 6.5 km. Heretofore, evidence of microbial life in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> has been elusive and difficult to validate. Because of the extreme conditions in these environments (high pressures and temperatures often in excess of 300 C), deep-sea <span class="hlt">hydrothermal</span>- <span class="hlt">vent</span> samplers must be robust. Because of the presumed low density of biomass of these environments, samplers must be capable of collecting water samples of significant volume. It is also essential to prevent contamination of samples by microbes entrained from surrounding waters. Prior to the development of the present apparatus, no sampling device was capable of satisfying these requirements. The apparatus (see figure) includes an intake equipped with a temperature probe, plus several other temperature probes located away from the intake. The readings from the temperature probes are utilized in conjunction with readings from flowmeters to determine the position of the intake relative to the <span class="hlt">hydrothermal</span> plume and, thereby, to position the intake to sample directly from the plume. Because it is necessary to collect large samples of water in order to obtain sufficient microbial biomass but it is not practical to retain all the water from the samples, four filter arrays are used to concentrate the microbial biomass (which is assumed to consist of particles larger than 0.2 m) into smaller volumes. The apparatus can collect multiple samples per dive and is designed to process a total volume of 10 L of <span class="hlt">vent</span> fluid, of which most passes through the filters, leaving a total possibly-microbe-containing sample volume of 200 mL remaining in filters. A rigid titanium nose at the intake is used for cooling the sample water before it enters a flexible inlet hose connected to a pump. As the water passes through the titanium nose, it must be cooled to a temperature that is above a mineral-precipitation temperature of 100 C but below the upper working temperature (230 C) of switching valves and tubes in the apparatus. The sample water then passes into a manifold tube, from whence the switching valves can direct the water through either a bypass tube or any one of the filter arrays, without contamination from a previous sample. Each filter array consists of series of filters having pore sizes decreasing in the direction of flow: 90-, 60-, 15-, and 7-micron prefilters and a large-surface-area 0.2-micron collection filter. All the filter taps are located between the intake and the bypass tube so that each time the bypass tube is used, the entire manifold tube is flushed as well.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985Sci...229..717J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985Sci...229..717J"><span id="translatedtitle">Geomicrobiology of Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jannasch, Holger W.; Mottl, Michael J.</p> <p>1985-08-01</p> <p>During the cycling of seawater through the earth's crust along the midocean ridge system, geothermal energy is transferred into chemical energy in the form of reduced inorganic compounds. These compounds are derived from the reaction of seawater with crustal rocks at high temperatures and are emitted from warm (<= 25 degrees C) and hot (~ 350 degrees C) submarine <span class="hlt">vents</span> at depths of 2000 to 3000 meters. Chemolithotrophic bacteria use these reduced chemical species as sources of energy for the reduction of carbon dioxide (assimilation) to organic carbon. These bacteria form the base of the food chain, which permits copious populations of certain specifically adapted invertebrates to grow in the immediate vicinity of the <span class="hlt">vents</span>. Such highly prolific, although narrowly localized, deep-sea communities are thus maintained primarily by terrestrial rather than by solar energy. Reduced sulfur compounds appear to represent the major electron donors for aerobic microbial metabolism, but methane-, hydrogen-, iron-, and manganese-oxidizing bacteria have also been found. Methanogenic, sulfur-respiring, and extremely thermophilic isolates carry out anaerobic chemosynthesis. Bacteria grow most abundantly in the shallow crust where upwelling hot, reducing <span class="hlt">hydrothermal</span> fluid mixes with downwelling cold, oxygenated seawater. The predominant production of biomass, however, is the result of symbiotic associations between chemolithotrophic bacteria and certain invertebrates, which have also been found as fossils in Cretaceous sulfide ores of ophiolite deposits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://xs1.somas.stonybrook.edu/~MADL/pubspdf/Raul-Bathymo.pdf','EPRINT'); return false;" href="http://xs1.somas.stonybrook.edu/~MADL/pubspdf/Raul-Bathymo.pdf"><span id="translatedtitle">Innate immunity in the deep sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel Bathymodiolus azoricus Raul Bettencourt a,</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Allam, Bassem</p> <p></p> <p>Innate immunity in the deep sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel Bathymodiolus azoricus Raul Bettencourt a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel Bathymodiolus azoricus. Cellular constituents in the hemolymph and extrapallial fluid October 2008 Available online 13 November 2008 Keywords: <span class="hlt">Hydrothermal</span> Bivalve Bathymodiolus azoricus</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFMOS43A0989S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFMOS43A0989S"><span id="translatedtitle">Macrofauna of shallow <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the Arctic Mid-Ocean Ridge at 71N</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schander, C.; Rapp, H. T.; Pedersen, R. B.</p> <p>2007-12-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are usually associated with a highly specialized fauna and since their discovery in 1977, more than 400 species of animals have been described. Specialized <span class="hlt">vent</span> fauna includes various animal phyla, but the most conspicuous and well known are annelids, mollusks and crustaceans. We have investigated the fauna collected around newly discovered <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the Mohns Ridge north of Jan Mayen. The <span class="hlt">venting</span> fields are located at 71°N and the <span class="hlt">venting</span> takes place within two main areas separated by 5 km. The shallowest <span class="hlt">vent</span> area is at 500-550 m water depth and is located at the base of a normal fault. This <span class="hlt">vent</span> field stretches approximately 1 km along the strike of the fault, and it is composed of 10-20 major <span class="hlt">vent</span> <span class="hlt">sites</span> each with multiple chimney constructions discharging up to 260°C hot fluids. A large area of diffuse, low- temperature <span class="hlt">venting</span> occurs in the area surrounding the high-temperature field. Here, partly microbial mediated iron-oxide-hydroxide deposits are abundant. The <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> do not show any high abundance of specialized <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fauna. Single groups (i.e. Porifera and Mollusca) have a few representatives but groups otherwise common in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> areas (e.g. vestimentifera, Alvinellid worms, mussels, clams, galathaeid and brachyuran crabs) are absent. Up until now slightly more than 200 species have been identified from the <span class="hlt">vent</span> area. The macrofauna found in the <span class="hlt">vent</span> area is, with few exceptions, an assortment of bathyal species known in the area. One endemic, yet undescribed, species of mollusc has been found so far, an gastropod related to Alvania incognita Warén, 1996 and A. angularis Warén, 1996 (Rissoidae), two species originally described from pieces of sunken wood north and south of Iceland. It is by far the most numerous mollusc species at the <span class="hlt">vents</span> and was found on smokers, in the bacterial mats, and on the ferric deposits. A single specimen of an undescribed tanaidacean has also ben found. The crinoid Heliometra glacialis is dominating large areas surrounding the <span class="hlt">vent</span> fields. Calcareous sponges were common in the area. Calcareous sponges normally represent only a minor fraction of the sponge fauna and it was therefore a big surprise that eight out of a total of 13 species reported here are calcareans. Annelids were the most speciose group with more than 80 identified species, followed by crustaceans. Possible explanations for the lack of typical <span class="hlt">vent</span> fauna is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMOS43C..05X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMOS43C..05X"><span id="translatedtitle">Heat flux measured acoustically at Grotto <span class="hlt">Vent</span>, a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> cluster on the Endeavour Segment, Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, G.; Jackson, D. R.; Bemis, K. G.; Rona, P. A.</p> <p>2013-12-01</p> <p>Over the past several decades, quantifying the heat output has been a unanimous focus of studies at <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields discovered around the global ocean. Despite their importance, direct measurements of <span class="hlt">hydrothermal</span> heat flux are very limited due to the remoteness of most <span class="hlt">vent</span> <span class="hlt">sites</span> and the complexity of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span>. Moreover, almost all the heat flux measurements made to date are snapshots and provide little information on the temporal variation that is expected from the dynamic nature of a <span class="hlt">hydrothermal</span> system. The Cabled Observatory <span class="hlt">Vent</span> Imaging Sonar (COVIS, https://<span class="hlt">sites</span>.google.com/a/uw.edu/covis/) is currently connected to the Endeavour node of the NEPTUNE Canada observatory network (http://www.neptunecanada.ca) to monitor the <span class="hlt">hydrothermal</span> plumes issuing from a <span class="hlt">vent</span> cluster (Grotto) on the Endeavour Segment of the Juan de Fuca Ridge. COVIS is acquiring a long-term (20-months to date) time series of the vertical flow rate and volume flux of the <span class="hlt">hydrothermal</span> plume above Grotto through the Doppler analysis of the acoustic backscatter data (Xu et al., 2013). We then estimate the plume heat flux from vertical flow rate and volume flux using our newly developed inverse method. In this presentation, we will briefly summarize the derivation of the inverse method and present the heat-flux time series obtained consequently with uncertainty quantification. In addition, we compare our heat-flux estimates with the one estimated from the plume in-situ temperatures measured using a Remotely Operative Vehicle (ROV) in 2012. Such comparison sheds light on the uncertainty of our heat flux estimation. Xu, G., Jackson, D., Bemis, K., and Rona, P., 2013, Observations of the volume flux of a seafloor <span class="hlt">hydrothermal</span> plume using an acoustic imaging sonar, Geochemistry, Geophysics Geosystems, 2013 (in press).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22233630','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22233630"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> fields and chemosynthetic biota on the world's deepest seafloor spreading centre.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Connelly, Douglas P; Copley, Jonathan T; Murton, Bramley J; Stansfield, Kate; Tyler, Paul A; German, Christopher R; Van Dover, Cindy L; Amon, Diva; Furlong, Maaten; Grindlay, Nancy; Hayman, Nicholas; Hühnerbach, Veit; Judge, Maria; Le Bas, Tim; McPhail, Stephen; Meier, Alexandra; Nakamura, Ko-Ichi; Nye, Verity; Pebody, Miles; Pedersen, Rolf B; Plouviez, Sophie; Sands, Carla; Searle, Roger C; Stevenson, Peter; Taws, Sarah; Wilcox, Sally</p> <p>2012-01-01</p> <p>The Mid-Cayman spreading centre is an ultraslow-spreading ridge in the Caribbean Sea. Its extreme depth and geographic isolation from other mid-ocean ridges offer insights into the effects of pressure on <span class="hlt">hydrothermal</span> <span class="hlt">venting</span>, and the biogeography of <span class="hlt">vent</span> fauna. Here we report the discovery of two <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields on the Mid-Cayman spreading centre. The Von Damm <span class="hlt">Vent</span> Field is located on the upper slopes of an oceanic core complex at a depth of 2,300?m. High-temperature <span class="hlt">venting</span> in this off-axis setting suggests that the global incidence of <span class="hlt">vent</span> fields may be underestimated. At a depth of 4,960?m on the Mid-Cayman spreading centre axis, the Beebe <span class="hlt">Vent</span> Field emits copper-enriched fluids and a buoyant plume that rises 1,100?m, consistent with >400?°C <span class="hlt">venting</span> from the world's deepest known <span class="hlt">hydrothermal</span> system. At both <span class="hlt">sites</span>, a new morphospecies of alvinocaridid shrimp dominates faunal assemblages, which exhibit similarities to those of Mid-Atlantic <span class="hlt">vents</span>. PMID:22233630</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3274706','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3274706"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> fields and chemosynthetic biota on the world's deepest seafloor spreading centre</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Connelly, Douglas P.; Copley, Jonathan T.; Murton, Bramley J.; Stansfield, Kate; Tyler, Paul A.; German, Christopher R.; Van Dover, Cindy L.; Amon, Diva; Furlong, Maaten; Grindlay, Nancy; Hayman, Nicholas; Hühnerbach, Veit; Judge, Maria; Le Bas, Tim; McPhail, Stephen; Meier, Alexandra; Nakamura, Ko-ichi; Nye, Verity; Pebody, Miles; Pedersen, Rolf B.; Plouviez, Sophie; Sands, Carla; Searle, Roger C.; Stevenson, Peter; Taws, Sarah; Wilcox, Sally</p> <p>2012-01-01</p> <p>The Mid-Cayman spreading centre is an ultraslow-spreading ridge in the Caribbean Sea. Its extreme depth and geographic isolation from other mid-ocean ridges offer insights into the effects of pressure on <span class="hlt">hydrothermal</span> <span class="hlt">venting</span>, and the biogeography of <span class="hlt">vent</span> fauna. Here we report the discovery of two <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields on the Mid-Cayman spreading centre. The Von Damm <span class="hlt">Vent</span> Field is located on the upper slopes of an oceanic core complex at a depth of 2,300?m. High-temperature <span class="hlt">venting</span> in this off-axis setting suggests that the global incidence of <span class="hlt">vent</span> fields may be underestimated. At a depth of 4,960?m on the Mid-Cayman spreading centre axis, the Beebe <span class="hlt">Vent</span> Field emits copper-enriched fluids and a buoyant plume that rises 1,100?m, consistent with >400?°C <span class="hlt">venting</span> from the world's deepest known <span class="hlt">hydrothermal</span> system. At both <span class="hlt">sites</span>, a new morphospecies of alvinocaridid shrimp dominates faunal assemblages, which exhibit similarities to those of Mid-Atlantic <span class="hlt">vents</span>. PMID:22233630</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DSRII.121..202B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DSRII.121..202B"><span id="translatedtitle">Where are the undiscovered <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on oceanic spreading ridges?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beaulieu, Stace E.; Baker, Edward T.; German, Christopher R.</p> <p>2015-11-01</p> <p>In nearly four decades since the discovery of deep-sea <span class="hlt">vents</span>, one-third of the length of global oceanic spreading ridges has been surveyed for <span class="hlt">hydrothermal</span> activity. Active submarine <span class="hlt">vent</span> fields are now known along the boundaries of 46 out of 52 recognized tectonic plates. <span class="hlt">Hydrothermal</span> survey efforts over the most recent decade were sparked by national and commercial interests in the mineral resource potential of seafloor <span class="hlt">hydrothermal</span> deposits, as well as by academic research. Here we incorporate recent data for back-arc spreading centers and ultraslow- and slow-spreading mid-ocean ridges (MORs) to revise a linear equation relating the frequency of <span class="hlt">vent</span> fields along oceanic spreading ridges to spreading rate. We apply this equation globally to predict a total number of <span class="hlt">vent</span> fields on spreading ridges, which suggests that ~900 <span class="hlt">vent</span> fields remain to be discovered. Almost half of these undiscovered <span class="hlt">vent</span> fields (comparable to the total of all <span class="hlt">vent</span> fields discovered during 35 years of research) are likely to occur at MORs with full spreading rates less than 60 mm/yr. We then apply the equation regionally to predict where these <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> may be discovered with respect to plate boundaries and national jurisdiction, with the majority expected to occur outside of states' exclusive economic zones. We hope that these predictions will prove useful to the community in the future, in helping to shape continuing ridge-crest exploration.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li class="active"><span>2</span></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_2 --> <div id="page_3" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="41"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5341819','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5341819"><span id="translatedtitle">Deep-sea primary production at the Galapagos <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Karl, D.M.; Wirsen, C.O.; Jannasch, H.W.</p> <p>1980-03-21</p> <p>Dense animal populations surrounding recently discovered <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> at the Galapagos Rift sea-floor spreading center, 2550 meters deep, are probably sustained by microbial primary production. Energy in the form of geothermically reduced sulfur compounds emitted from the <span class="hlt">vents</span> is liberated during oxidation and used for the reduction of carbon dioxide to organic matter by chemosynthetic bacteria.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.B53D..08O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.B53D..08O"><span id="translatedtitle">Isolation and Stability of Distinct Subsurface Microbial Communities Associated with Two <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Opatkiewicz, A. D.; Butterfield, D. A.; Baross, J. A.</p> <p>2008-12-01</p> <p>Subseafloor microbial communities may be important in global primary production and biogeochemical cycling. However, too little is known about the physiological and phylogenetic diversity and activity of these communities to assess this potential, and understanding the temporal and spatial variability in microbial community structure is critical. The microbial community structure of five geographically distinct <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> located within the Axial Seamount caldera, and four geographically distinct <span class="hlt">vents</span> within the Main Endeavour Field, Juan de Fuca Ridge, were examined over six years. Terminal restriction fragment length polymorphism (tRFLP) and 16S rRNA gene sequence analyses were used to determine the bacterial and archaeal diversity, and the statistical software Primer was used to compare <span class="hlt">vent</span> microbiology, temperature and fluid chemistry. Statistical analysis of <span class="hlt">vent</span> fluid temperature and chemical composition shows that there are significant differences between <span class="hlt">vents</span> in any year, and persistent differences in composition between one of the Axial <span class="hlt">vents</span> compared to the rest of the <span class="hlt">vents</span>. For the majority of <span class="hlt">vents</span>, however, the fluid composition changed over time such that separate <span class="hlt">vents</span> do not maintain a statistically distinct composition. In contrast, the subseafloor microbial communities associated with individual <span class="hlt">vents</span> also changed from year to year but each location maintained a distinct community structure (based on tRFLP and 16S rRNA gene sequence analyses) that was significantly different and greater than 60-percent dissimilar from all other <span class="hlt">vents</span> included in this study. At Axial, epsilon-proteobacterial microdiversity is shown to be important in distinguishing <span class="hlt">vent</span> communities. The deeper, high-temperature archaeal communities have more overlap between <span class="hlt">sites</span>. We propose that persistent <span class="hlt">venting</span> at many diffuse <span class="hlt">sites</span> over time creates the potential to isolate and stabilize diverse microbial community structures between <span class="hlt">vents</span>. Variation in dilution patterns along discrete flow channels feeding diffuse seafloor <span class="hlt">vents</span> promotes microbial diversity and uniqueness of different diffuse <span class="hlt">vent</span> <span class="hlt">sites</span>, especially among the thermophilic Bacteria within the 5-50°C sub-seafloor temperature range.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://chuma.cas.usf.edu/~pichler/papers/CHEMGEO%202005%20Dominica.pdf','EPRINT'); return false;" href="http://chuma.cas.usf.edu/~pichler/papers/CHEMGEO%202005%20Dominica.pdf"><span id="translatedtitle">Geochemistry of Champagne Hot Springs shallow <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field and associated sediments, Dominica, Lesser Antilles</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Pichler, Thomas</p> <p></p> <p>Geochemistry of Champagne Hot Springs shallow <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field and associated sediments and precipitate chemistry, as well as comparing the submarine <span class="hlt">vent</span> chemistry with nearby on-land <span class="hlt">hydrothermal</span> <span class="hlt">hydrothermal</span> <span class="hlt">venting</span>, located approximately 40 m to the north of CHS. This area consists of <span class="hlt">hydrothermally</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22325568','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22325568"><span id="translatedtitle">New digestive symbiosis in the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> amphipoda Ventiella sulfuris.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Corbari, Laure; Durand, Lucile; Cambon-Bonavita, Marie-Anne; Gaill, Françoise; Compère, Philippe</p> <p>2012-02-01</p> <p>Ventiella sulfuris Barnard and Ingram, 1990 is the most abundant amphipod species inhabiting the Eastern Pacific Rise (EPR 9°N) <span class="hlt">vent</span> fields. This <span class="hlt">vent</span>-endemic species is frequently encountered near colonies of Pompeii worms Alvinella pompejana. V. sulfuris specimens were collected during the oceanographic cruise LADDER II at the Bio9 (9°50.3'N, 2508m depth) <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">site</span>. Main objectives were to highlight the occurrence of bacterial symbiosis in V. sulfuris and to hypothesise their implications in nutrition. Observations in light and electron microscopy (SEM, TEM) showed that the outer body surface and appendages are free of microorganisms. In contrast, the digestive system revealed two major microbial communities settled in the midgut and in the hindgut. Gut contents showed bacterial traces together with abundant fragments of Alvinellid cuticle and setae, from A. pompejana, suggesting that V. sulfuris could directly feed on Alvinellids and/or on their bacterial epibionts. Molecular analyses based on the 16S rRNA genes revealed the diversity of bacterial communities in the digestive system, of which, the Epsilonproteobacteria phylum, could be considered as one of the major bacterial group. Hypotheses were proposed on their symbiotic features and their implications in V. sulfuris nutrition. PMID:22325568</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5203065','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5203065"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> of Yellowstone Lake, Yellowstone National Park, Wyoming</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kaplinski, M.A.; Morgan, P. . Geology Dept.)</p> <p>1993-04-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> systems within Yellowstone Lake are located within the Yellowstone caldera in the northeastern and West Thumb sections of the lake. The <span class="hlt">vent</span> systems lie within areas of extremely high geothermal gradients (< 1,000 C/km) in the lake sediments and occur as clusters of individual <span class="hlt">vents</span> that expel both <span class="hlt">hydrothermal</span> fluids and gas. Regions surrounding the <span class="hlt">vents</span> are colonized by unique, chemotropic biologic communities and suggest that <span class="hlt">hydrothermal</span> input plays an important role in the nutrient dynamics of the lake's ecosystem. The main concentration of <span class="hlt">hydrothermal</span> activity occurs in the northeast region of the main lake body in a number of locations including: (1) along the shoreline from the southern edge of Sedge Bay to the inlet of Pelican Creek; (2) the central portion of the partially submerged Mary Bay phreatic explosion crater, within deep (30--50 m) fissures; (3) along the top of a 3 km long, steep-sided ridge that extends from the southern border of Mary Bay, south-southeast into the main lake basin; and (4) east of Stevenson Island along the lower portion of the slope (50--107 m) into the lake basin, within an anastomosing series of north to northwest trending, narrow troughs or fissures. <span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> were also located within, and surrounding the West Thumb of Yellowstone Lake, with the main concentration occurring the offshore of the West Thumb and Potts Geyser Basin. <span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> in Yellowstone Lake occur along fractures that have penetrated the lake sediments or along the tops of ridges and near shore areas. Underneath the lake, rising <span class="hlt">hydrothermal</span> fluids encounter a semi-permeable cap of lake sediments. Upwardly convecting <span class="hlt">hydrothermal</span> fluid flow may be diverted by the impermeable lake sediments along the buried, pre-existing topography. These fluids may continue to rise along topography until fractures are encountered, or the lake sediment cover is thinned sufficiently to allow egress of the fluids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7049404','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/7049404"><span id="translatedtitle">Deep sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. (Latest citations from Oceanic abstracts). Published Search</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Not Available</p> <p>1994-04-01</p> <p>The bibliography contains citations concerning biological, chemical, and geophysical investigations of seafloor <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Biological community descriptions, primary production and growth studies, the nature and occurrence of mineral deposits, and the structure and morphology of <span class="hlt">vent</span> systems are among the topics discussed. Specific <span class="hlt">site</span> studies, and general investigations are considered. (Contains a minimum of 157 citations and includes a subject term index and title list.)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GGG....14.4892B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GGG....14.4892B"><span id="translatedtitle">An authoritative global database for active submarine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beaulieu, Stace E.; Baker, Edward T.; German, Christopher R.; Maffei, Andrew</p> <p>2013-11-01</p> <p>The InterRidge <span class="hlt">Vents</span> Database is available online as the authoritative reference for locations of active submarine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields. Here we describe the revision of the database to an open source content management system and conduct a meta-analysis of the global distribution of known active <span class="hlt">vent</span> fields. The number of known active <span class="hlt">vent</span> fields has almost doubled in the past decade (521 as of year 2009), with about half visually confirmed and others inferred active from physical and chemical clues. Although previously known mainly from mid-ocean ridges (MORs), active <span class="hlt">vent</span> fields at MORs now comprise only half of the total known, with about a quarter each now known at volcanic arcs and back-arc spreading centers. Discoveries in arc and back-arc settings resulted in an increase in known <span class="hlt">vent</span> fields within exclusive economic zones, consequently reducing the proportion known in high seas to one third. The increase in known <span class="hlt">vent</span> fields reflects a number of factors, including increased national and commercial interests in seafloor <span class="hlt">hydrothermal</span> deposits as mineral resources. The purpose of the database now extends beyond academic research and education and into marine policy and management, with at least 18% of known <span class="hlt">vent</span> fields in areas granted or pending applications for mineral prospecting and 8% in marine protected areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950057135&hterms=amino+acid&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Damino%2Bacid','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950057135&hterms=amino+acid&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Damino%2Bacid"><span id="translatedtitle">The stability of amino acids at submarine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> temperatures</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bada, Jeffrey L.; Miller, Stanley L.; Zhao, Meixun</p> <p>1995-01-01</p> <p>It has been postulated that amino acid stability at <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> temperatures is controlled by a metastable thermodynamic equilibrium rather than by kinetics. Experiments reported here demonstrate that the amino acids are irreversibly destroyed by heating at 240 C and that quasi-equilibrium calculations give misleading descriptions of the experimental observations. Equilibrium thermodynamic calculations are not applicable to organic compounds under high-temperature submarine <span class="hlt">vent</span> conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16871216','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16871216"><span id="translatedtitle">A ubiquitous thermoacidophilic archaeon from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Reysenbach, Anna-Louise; Liu, Yitai; Banta, Amy B; Beveridge, Terry J; Kirshtein, Julie D; Schouten, Stefan; Tivey, Margaret K; Von Damm, Karen L; Voytek, Mary A</p> <p>2006-07-27</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are important in global biogeochemical cycles, providing biological oases at the sea floor that are supported by the thermal and chemical flux from the Earth's interior. As hot, acidic and reduced <span class="hlt">hydrothermal</span> fluids mix with cold, alkaline and oxygenated sea water, minerals precipitate to form porous sulphide-sulphate deposits. These structures provide microhabitats for a diversity of prokaryotes that exploit the geochemical and physical gradients in this dynamic ecosystem. It has been proposed that fluid pH in the actively <span class="hlt">venting</span> sulphide structures is generally low (pH < 4.5), yet no extreme thermoacidophile has been isolated from <span class="hlt">vent</span> deposits. Culture-independent surveys based on ribosomal RNA genes from deep-sea <span class="hlt">hydrothermal</span> deposits have identified a widespread euryarchaeotal lineage, DHVE2 (deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> euryarchaeotic 2). Despite the ubiquity and apparent deep-sea endemism of DHVE2, cultivation of this group has been unsuccessful and thus its metabolism remains a mystery. Here we report the isolation and cultivation of a member of the DHVE2 group, which is an obligate thermoacidophilic sulphur- or iron-reducing heterotroph capable of growing from pH 3.3 to 5.8 and between 55 and 75 degrees C. In addition, we demonstrate that this isolate constitutes up to 15% of the archaeal population, providing evidence that thermoacidophiles may be key players in the sulphur and iron cycling at deep-sea <span class="hlt">vents</span>. PMID:16871216</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70028504','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70028504"><span id="translatedtitle">A ubiquitous thermoacidophilic archaeon from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Reysenbach, A.-L.; Liu, Yajing; Banta, A.B.; Beveridge, T.J.; Kirshtein, J.D.; Schouten, S.; Tivey, M.K.; Von Damm, K. L.; Voytek, M.A.</p> <p>2006-01-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are important in global biogeochemical cycles, providing biological oases at the sea floor that are supported by the thermal and chemical flux from the Earth's interior. As hot, acidic and reduced <span class="hlt">hydrothermal</span> fluids mix with cold, alkaline and oxygenated sea water, minerals precipitate to form porous sulphide-sulphate deposits. These structures provide microhabitats for a diversity of prokaryotes that exploit the geochemical and physical gradients in this dynamic ecosystem. It has been proposed that fluid pH in the actively <span class="hlt">venting</span> sulphide structures is generally low (pH < 4.5), yet no extreme thermoacidophile has been isolated from <span class="hlt">vent</span> deposits. Culture-independent surveys based on ribosomal RNA genes from deep-sea <span class="hlt">hydrothermal</span> deposits have identified a widespread euryarchaeotal lineage, DHVE2 (deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> euryarchaeotic 2). Despite the ubiquity and apparent deep-sea endemism of DHVE2, cultivation of this group has been unsuccessful and thus its metabolism remains a mystery. Here we report the isolation and cultivation of a member of the DHVE2 group, which is an obligate thermoacidophilic sulphur- or iron-reducing heterotroph capable of growing from pH 3.3 to 5.8 and between 55 and 75??C. In addition, we demonstrate that this isolate constitutes up to 15% of the archaeal population, providing evidence that thermoacidophiles may be key players in the sulphur and iron cycling at deep-sea <span class="hlt">vents</span>. ?? 2006 Nature Publishing Group.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12422215','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12422215"><span id="translatedtitle">Adaptive visual metamorphosis in a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> crab.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jinks, Robert N; Markley, Tara L; Taylor, Elizabeth E; Perovich, Gina; Dittel, Ana I; Epifanio, Charles E; Cronin, Thomas W</p> <p>2002-11-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> along the mid-ocean ridges host ephemeral ecosystems of diverse endemic fauna including several crustacean species, some of which undergo planktonic development as larvae up to 1,000 m above and 100 km away from the <span class="hlt">vents</span>. Little is known about the role of vision in the life history of <span class="hlt">vent</span> fauna. Here we report that planktonic zoea larvae of the <span class="hlt">vent</span> crab Bythograea thermydron possess image-forming compound eyes with a visual pigment sensitive to the blue light of mesopelagic waters. As they metamorphose and begin to descend to and settle at the <span class="hlt">vents</span>, they lose their image-forming optics and develop high-sensitivity naked-retina eyes. The spectral absorbance of the visual pigment in these eyes shifts towards longer wavelengths from larva to postlarva to adult. This progressive visual metamorphosis trades imaging for increased sensitivity, and changes spectral sensitivity from the blue wavelengths of the larval environment towards the dim, longer wavelengths produced in the deeper bathypelagic <span class="hlt">vent</span> environment of the adults. As <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> produce light, vision may supplement thermal and chemical senses to orient postlarval settlement at <span class="hlt">vent</span> <span class="hlt">sites</span>. PMID:12422215</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ldeo.columbia.edu/~winckler/Publications_files/winckler_et_al_2009GL042093.pdf','EPRINT'); return false;" href="http://www.ldeo.columbia.edu/~winckler/Publications_files/winckler_et_al_2009GL042093.pdf"><span id="translatedtitle">Mantle helium reveals Southern Ocean <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> Gisela Winckler,1,2</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Winckler, Gisela</p> <p></p> <p>Click Here for Full Article Mantle helium reveals Southern Ocean <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> Gisela; accepted 21 January 2010; published 2 March 2010. [1] <span class="hlt">Hydrothermal</span> <span class="hlt">venting</span> along the global midocean ridge of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span>. We identify three complete ridge segments, a portion of a fourth segment and two isolated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ldeo.columbia.edu/~scw/Site/Publications_files/2003JGRGoldenWebb.pdf','EPRINT'); return false;" href="http://www.ldeo.columbia.edu/~scw/Site/Publications_files/2003JGRGoldenWebb.pdf"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> microearthquake swarms beneath active <span class="hlt">vents</span> at Middle Valley, northern Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Webb, Spahr C.</p> <p></p> <p><span class="hlt">Hydrothermal</span> microearthquake swarms beneath active <span class="hlt">vents</span> at Middle Valley, northern Juan de Fuca Dog <span class="hlt">vent</span> field, a major <span class="hlt">hydrothermal</span> area in Middle Valley with exit fluid temperatures near 270°C, <span class="hlt">Hydrothermal</span> microearthquake swarms beneath active <span class="hlt">vents</span> at Middle Valley, northern Juan de Fuca Ridge, J</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.mit.edu/~mingdao/papers/2010_PNAS_snail_protection_mechanism.pdf','EPRINT'); return false;" href="http://www.mit.edu/~mingdao/papers/2010_PNAS_snail_protection_mechanism.pdf"><span id="translatedtitle">Protection mechanisms of the iron-plated armor of a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> gastropod</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Dao, Ming</p> <p></p> <p>Protection mechanisms of the iron-plated armor of a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> gastropod Haimin from the Kairei Indian <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field, which is unlike any other known natural or synthetic of a gastropod mollusc from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> [order Neomphalina (18), family Peltospiridae (19</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.oeb.harvard.edu/faculty/girguis/pdf/2002GirguisEffects.pdf','EPRINT'); return false;" href="http://www.oeb.harvard.edu/faculty/girguis/pdf/2002GirguisEffects.pdf"><span id="translatedtitle">The discovery of chemoautotrophic symbionts in the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworm Riftia pachyptila expanded our</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Girguis, Peter R.</p> <p></p> <p>The discovery of chemoautotrophic symbionts in the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworm Riftia pachyptila at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, hydrocarbon seeps and other chemically reduced deep-sea environments, exhibit a suite the symbiont's metabolic requirements, including the elimination of waste products. The <span class="hlt">hydrothermal</span> <span class="hlt">vent</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.fluidcontinuity.org/publications/Crone2006.pdf','EPRINT'); return false;" href="http://www.fluidcontinuity.org/publications/Crone2006.pdf"><span id="translatedtitle">The Sound Generated by Mid-Ocean Ridge Black Smoker <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Crone, Timothy J.</p> <p></p> <p>The Sound Generated by Mid-Ocean Ridge Black Smoker <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> Timothy J. Crone*, William S, Seattle, Washington, United States of America <span class="hlt">Hydrothermal</span> flow through seafloor black smoker <span class="hlt">vents</span> Generated by Mid-Ocean Ridge Black Smoker <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span>. PLoS ONE 1(1): e133. doi:10.1371/journal</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994DSRI...41.1407B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994DSRI...41.1407B"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">venting</span> at endeavour ridge: effect on zooplankton biomass throughout the water column</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burd, Brenda J.; Thomson, Richard E.</p> <p>1994-09-01</p> <p>Bio-acoustical data reveal that the <span class="hlt">hydrothermal</span> plume emanating from the main <span class="hlt">vent</span> field near 2100 m depth on Endeavour Ridge (47°57'N, 129°06'W) affects the distribution and migration of zooplankton throughout the entire water column. Net samples taken in July of 1991 and 1992 show that the standing stock of macrozooplankton integrated over the water column was considerably higher within several kilometers of the main <span class="hlt">vent</span> <span class="hlt">site</span> than at locations tens of kilometers from the <span class="hlt">vent</span> <span class="hlt">site</span>. Community analysis reveals that there were distinct shallow (<800 m depth) and deep (>800 m depth) faunal assemblages in the <span class="hlt">vent</span> region. Shallow fauna infiltrated the deep zooplankton acoustic scattering layers in the immediate vicinity of Endeavour Ridge, producing a mixed assemblage of animals, including large numbers of juvenile filter-feeding copepods and their predators that normally inhabit the shallow layer. In contrast, the deep acoustic scattering layers found 11 km to the southeast and 15 km to the north of the central <span class="hlt">vent</span> field in 1991, and 50 km to the west of the central <span class="hlt">vent</span> field in 1992, were composed of distinctly deep-sea fauna. The enhanced, vertically-integrated biomass over the <span class="hlt">vent</span> region appears to result from vertical migration of zooplankton. A simple circulation model indicates that fauna can make the round-trip journey between the top of the plume and the upper ocean without being advected beyond the range of the detectable <span class="hlt">hydrothermal</span> effluent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4359681','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4359681"><span id="translatedtitle">Mineralization of Alvinella polychaete tubes at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Georgieva, M N; Little, C T S; Ball, A D; Glover, A G</p> <p>2015-01-01</p> <p>Alvinellid polychaete worms form multilayered organic tubes in the hottest and most rapidly growing areas of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimneys. Over short periods of time, these tubes can become entirely mineralized within this environment. Documenting the nature of this process in terms of the stages of mineralization, as well as the mineral textures and end products that result, is essential for our understanding of the fossilization of polychaetes at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Here, we report in detail the full mineralization of Alvinella spp. tubes collected from the East Pacific Rise, determined through the use of a wide range of imaging and analytical techniques. We propose a new model for tube mineralization, whereby mineralization begins as templating of tube layer and sublayer surfaces and results in fully mineralized tubes comprised of multiple concentric, colloform, pyrite bands. Silica appeared to preserve organic tube layers in some samples. Fine-scale features such as protein fibres, extracellular polymeric substances and two types of filamentous microbial colonies were also found to be well preserved within a subset of the tubes. The fully mineralized Alvinella spp. tubes do not closely resemble known ancient <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tube fossils, corroborating molecular evidence suggesting that the alvinellids are a relatively recent polychaete lineage. We also compare pyrite and silica preservation of organic tissues within <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> to soft tissue preservation in sediments and hot springs. PMID:25556400</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25556400','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25556400"><span id="translatedtitle">Mineralization of Alvinella polychaete tubes at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Georgieva, M N; Little, C T S; Ball, A D; Glover, A G</p> <p>2015-03-01</p> <p>Alvinellid polychaete worms form multilayered organic tubes in the hottest and most rapidly growing areas of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimneys. Over short periods of time, these tubes can become entirely mineralized within this environment. Documenting the nature of this process in terms of the stages of mineralization, as well as the mineral textures and end products that result, is essential for our understanding of the fossilization of polychaetes at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Here, we report in detail the full mineralization of Alvinella spp. tubes collected from the East Pacific Rise, determined through the use of a wide range of imaging and analytical techniques. We propose a new model for tube mineralization, whereby mineralization begins as templating of tube layer and sublayer surfaces and results in fully mineralized tubes comprised of multiple concentric, colloform, pyrite bands. Silica appeared to preserve organic tube layers in some samples. Fine-scale features such as protein fibres, extracellular polymeric substances and two types of filamentous microbial colonies were also found to be well preserved within a subset of the tubes. The fully mineralized Alvinella spp. tubes do not closely resemble known ancient <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tube fossils, corroborating molecular evidence suggesting that the alvinellids are a relatively recent polychaete lineage. We also compare pyrite and silica preservation of organic tissues within <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> to soft tissue preservation in sediments and hot springs. PMID:25556400</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.B12A0771G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.B12A0771G"><span id="translatedtitle"><span class="hlt">Vent</span> Plume Characteristics at the Lost City <span class="hlt">Hydrothermal</span> Field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Glickson, D. A.; Nakamura, K.; Olson, E. J.; Larson, B.; Proskurowski, G.; Lilley, M. D.; Kelley, D. S.</p> <p>2003-12-01</p> <p>Lost City is a peridotite-hosted <span class="hlt">hydrothermal</span> field driven by exothermic serpentinization reactions at depth. <span class="hlt">Venting</span> of high pH (9-11), 40-90° C fluids and seawater promotes growth of carbonate structures that reach up to 60 m in height. To characterize the plume around this novel actively <span class="hlt">venting</span> field and to investigate other potential <span class="hlt">venting</span> <span class="hlt">sites</span>, 14 CTD casts were completed in the vicinity of the field. In addition to potential temperature, conductivity, and oxygen, hydrocasts were also equipped with an Eh sensor to measure redox potential through the water column. Fluids from 11 of these casts were also sampled for hydrogen and methane, as these gases are byproducts of serpentinization reactions. To quantify the strongest <span class="hlt">hydrothermal</span> signals, four casts were taken directly above and adjacent to Poseidon, the largest structure in the field (60 m tall, reaching to an elevation of 730 m). To place constraints on the extent of plume movement at Lost City, one cast was taken 125 m to the west, another 75 m to the east, and 2 were taken in a shallow depression that bounds the field 50-60 m to the north. Of the 9 casts proximal to the field, almost all showed a moderate to steep increase in Eh values 10-20 m off the bottom. Dramatic gradients in Eh occurred near bottom at all boundary stations as well. Hydrogen concentrations 100 times those of background ocean waters were measured near bottom at stations just north of the field and strong signals up to 20x background were measured near and to the east of Poseidon. Highly elevated methane concentrations were measured at the eastern boundary cast (180 nM), while other stations to the north and east of the main Lost City field had moderately elevated values (40-55 nM, up to 30x background). Higher concentrations of both hydrogen and methane were consistently found in the 750-800 m depth range. These data show that plumes derived solely from serpentinization reactions are characterized by steep gradients in Eh and elevated volatile concentrations very near bottom. In contrast to plumes associated with black smoker systems, the limited buoyancy of Lost City-like plumes and lack of particulate or strong thermal anomalies will make prospecting for other peridotite-hosted systems challenging.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36..334J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36..334J"><span id="translatedtitle">NASA/JPL <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> bio-sampler</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jonsson, J.; Behar, A.; Bruckner, J.; Matthews, J.</p> <p></p> <p>pagestyle empty begin document On the bottom of the oceans with volcanic activity present <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> can be found which spew out mineral rich superheated water from the porous seafloor crust Some of these <span class="hlt">vents</span> are situated several thousands of meters below the surface where the sunlight never reaches Yet life thrives here on the minerals and chemical compounds that the <span class="hlt">vent</span> water brings up with it This chemosynthetic microbial community forms the basis of some of the most interesting ecosystems on our planet and could possibly also be found on other water rich planets and moons in the solar system Perhaps under the icy surface of the moon Europa there exist <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> with such biota thriving independently of the solar energy The <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Bio-sampler HVB is a system which will be used to collect pristine samples of the water emanating from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> An array of temperature and flow sensors will monitor the sampling conditions This will allow for the samples to be collected from defined locations within the plume and the diversity and distribution of the chemosynthetic communities that might live there can be accurately described The samples will have to be taken without any contamination from the surrounding water thus the pristine requirement Monitoring the flow will assure that enough water has been sampled to account for the low biomass of these environments The system will be using a series of filters down to 0 2 mu m in pore size and the samples can be directly collected from the system for both culture-</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060042927&hterms=Hydrothermal+vents&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2528Hydrothermal%2Bvents%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060042927&hterms=Hydrothermal+vents&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2528Hydrothermal%2Bvents%2529"><span id="translatedtitle">A deep sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Bio-sampler for large volume in-situ filtration of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Behar, Alberto; Matthews, Jaret; Venkateswaran, Kasthuri; Bruckner, James; Basic, Goran; So, Edmond; Rivadeneyra, Cesar</p> <p>2005-01-01</p> <p>This paper provides a physical description of the current system, as well as a summary of the preliminary tests conducted in 2005: a pressure chamber test, a dive test in a 30 foot dive pool, and a dive operation at a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> off the northern coast of Iceland.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000ECSS...51..627P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000ECSS...51..627P"><span id="translatedtitle">The Sponge Community of a Subtidal Area with <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span>: Milos Island, Aegean Sea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pansini, M.; Morri, C.; Bianchi, C. N.</p> <p>2000-11-01</p> <p>Sponges were sampled by SCUBA diving at six subtidal rocky <span class="hlt">sites</span>, three of which were close to <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, a common feature on the sea-floor off the south-east coast of Milos. Twenty-five species (2 Calcarea and 23 Demospongiae) were found, few compared with the 589 recorded for the Mediterranean, but an important addition to the scant information on the sponge fauna of the Aegean Sea. The number of species found at <span class="hlt">vent</span> <span class="hlt">sites</span> was consistently higher than that found at non-<span class="hlt">vent</span> <span class="hlt">sites</span>, but no <span class="hlt">vent</span>-obligate species could be identified. However, Geodia cydonium and three species of Cliona ( C. copiosa, C. nigricans and C. rhodensis) showed a tendency to colonize <span class="hlt">vent</span> areas. The former might take advantage of increased silica availability, the latter of the enhanced deposition of carbonates near <span class="hlt">vents</span>. Substratum cover by sponges (estimated from wire-framed photographs of 0·7 m 2), varied greatly both among and within <span class="hlt">sites</span>, mostly according to slope. Most sponge species preferred vertical to overhanging, shaded substrata. Proximity to <span class="hlt">vents</span> seemed to have little or no influence on sponge cover, notwithstanding a primary effect on species diversity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26154881','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26154881"><span id="translatedtitle">RNA Oligomerization in Laboratory Analogues of Alkaline <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Systems.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Burcar, Bradley T; Barge, Laura M; Trail, Dustin; Watson, E Bruce; Russell, Michael J; McGown, Linda B</p> <p>2015-07-01</p> <p>Discovering pathways leading to long-chain RNA formation under feasible prebiotic conditions is an essential step toward demonstrating the viability of the RNA World hypothesis. Intensive research efforts have provided evidence of RNA oligomerization by using circular ribonucleotides, imidazole-activated ribonucleotides with montmorillonite catalyst, and ribonucleotides in the presence of lipids. Additionally, mineral surfaces such as borates, apatite, and calcite have been shown to catalyze the formation of small organic compounds from inorganic precursors (Cleaves, 2008 ), pointing to possible geological <span class="hlt">sites</span> for the origins of life. Indeed, the catalytic properties of these particular minerals provide compelling evidence for alkaline <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> as a potential <span class="hlt">site</span> for the origins of life since, at these <span class="hlt">vents</span>, large metal-rich chimney structures can form that have been shown to be energetically favorable to diverse forms of life. Here, we test the ability of iron- and sulfur-rich chimneys to support RNA oligomerization reactions using imidazole-activated and non-activated ribonucleotides. The chimneys were synthesized in the laboratory in aqueous "ocean" solutions under conditions consistent with current understanding of early Earth. Effects of elemental composition, pH, inclusion of catalytic montmorillonite clay, doping of chimneys with small organic compounds, and in situ ribonucleotide activation on RNA polymerization were investigated. These experiments, under certain conditions, showed successful dimerization by using unmodified ribonucleotides, with the generation of RNA oligomers up to 4 units in length when imidazole-activated ribonucleotides were used instead. Elemental analysis of the chimney precipitates and the reaction solutions showed that most of the metal cations that were determined were preferentially partitioned into the chimneys. PMID:26154881</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3250512','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3250512"><span id="translatedtitle">The Discovery of New Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Communities in the Southern Ocean and Implications for Biogeography</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rogers, Alex D.; Tyler, Paul A.; Connelly, Douglas P.; Copley, Jon T.; James, Rachael; Larter, Robert D.; Linse, Katrin; Mills, Rachel A.; Garabato, Alfredo Naveira; Pancost, Richard D.; Pearce, David A.; Polunin, Nicholas V. C.; German, Christopher R.; Shank, Timothy; Boersch-Supan, Philipp H.; Alker, Belinda J.; Aquilina, Alfred; Bennett, Sarah A.; Clarke, Andrew; Dinley, Robert J. J.; Graham, Alastair G. C.; Green, Darryl R. H.; Hawkes, Jeffrey A.; Hepburn, Laura; Hilario, Ana; Huvenne, Veerle A. I.; Marsh, Leigh; Ramirez-Llodra, Eva; Reid, William D. K.; Roterman, Christopher N.; Sweeting, Christopher J.; Thatje, Sven; Zwirglmaier, Katrin</p> <p>2012-01-01</p> <p>Since the first discovery of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> along the Galápagos Rift in 1977, numerous <span class="hlt">vent</span> <span class="hlt">sites</span> and endemic faunal assemblages have been found along mid-ocean ridges and back-arc basins at low to mid latitudes. These discoveries have suggested the existence of separate biogeographic provinces in the Atlantic and the North West Pacific, the existence of a province including the South West Pacific and Indian Ocean, and a separation of the North East Pacific, North East Pacific Rise, and South East Pacific Rise. The Southern Ocean is known to be a region of high deep-sea species diversity and centre of origin for the global deep-sea fauna. It has also been proposed as a gateway connecting <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in different oceans but is little explored because of extreme conditions. Since 2009 we have explored two segments of the East Scotia Ridge (ESR) in the Southern Ocean using a remotely operated vehicle. In each segment we located deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> hosting high-temperature black smokers up to 382.8°C and diffuse <span class="hlt">venting</span>. The chemosynthetic ecosystems hosted by these <span class="hlt">vents</span> are dominated by a new yeti crab (Kiwa n. sp.), stalked barnacles, limpets, peltospiroid gastropods, anemones, and a predatory sea star. Taxa abundant in <span class="hlt">vent</span> ecosystems in other oceans, including polychaete worms (Siboglinidae), bathymodiolid mussels, and alvinocaridid shrimps, are absent from the ESR <span class="hlt">vents</span>. These groups, except the Siboglinidae, possess planktotrophic larvae, rare in Antarctic marine invertebrates, suggesting that the environmental conditions of the Southern Ocean may act as a dispersal filter for <span class="hlt">vent</span> taxa. Evidence from the distinctive fauna, the unique community structure, and multivariate analyses suggest that the Antarctic <span class="hlt">vent</span> ecosystems represent a new <span class="hlt">vent</span> biogeographic province. However, multivariate analyses of species present at the ESR and at other deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> globally indicate that <span class="hlt">vent</span> biogeography is more complex than previously recognised. PMID:22235194</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22235194','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22235194"><span id="translatedtitle">The discovery of new deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> communities in the southern ocean and implications for biogeography.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rogers, Alex D; Tyler, Paul A; Connelly, Douglas P; Copley, Jon T; James, Rachael; Larter, Robert D; Linse, Katrin; Mills, Rachel A; Garabato, Alfredo Naveira; Pancost, Richard D; Pearce, David A; Polunin, Nicholas V C; German, Christopher R; Shank, Timothy; Boersch-Supan, Philipp H; Alker, Belinda J; Aquilina, Alfred; Bennett, Sarah A; Clarke, Andrew; Dinley, Robert J J; Graham, Alastair G C; Green, Darryl R H; Hawkes, Jeffrey A; Hepburn, Laura; Hilario, Ana; Huvenne, Veerle A I; Marsh, Leigh; Ramirez-Llodra, Eva; Reid, William D K; Roterman, Christopher N; Sweeting, Christopher J; Thatje, Sven; Zwirglmaier, Katrin</p> <p>2012-01-01</p> <p>Since the first discovery of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> along the Galápagos Rift in 1977, numerous <span class="hlt">vent</span> <span class="hlt">sites</span> and endemic faunal assemblages have been found along mid-ocean ridges and back-arc basins at low to mid latitudes. These discoveries have suggested the existence of separate biogeographic provinces in the Atlantic and the North West Pacific, the existence of a province including the South West Pacific and Indian Ocean, and a separation of the North East Pacific, North East Pacific Rise, and South East Pacific Rise. The Southern Ocean is known to be a region of high deep-sea species diversity and centre of origin for the global deep-sea fauna. It has also been proposed as a gateway connecting <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in different oceans but is little explored because of extreme conditions. Since 2009 we have explored two segments of the East Scotia Ridge (ESR) in the Southern Ocean using a remotely operated vehicle. In each segment we located deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> hosting high-temperature black smokers up to 382.8°C and diffuse <span class="hlt">venting</span>. The chemosynthetic ecosystems hosted by these <span class="hlt">vents</span> are dominated by a new yeti crab (Kiwa n. sp.), stalked barnacles, limpets, peltospiroid gastropods, anemones, and a predatory sea star. Taxa abundant in <span class="hlt">vent</span> ecosystems in other oceans, including polychaete worms (Siboglinidae), bathymodiolid mussels, and alvinocaridid shrimps, are absent from the ESR <span class="hlt">vents</span>. These groups, except the Siboglinidae, possess planktotrophic larvae, rare in Antarctic marine invertebrates, suggesting that the environmental conditions of the Southern Ocean may act as a dispersal filter for <span class="hlt">vent</span> taxa. Evidence from the distinctive fauna, the unique community structure, and multivariate analyses suggest that the Antarctic <span class="hlt">vent</span> ecosystems represent a new <span class="hlt">vent</span> biogeographic province. However, multivariate analyses of species present at the ESR and at other deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> globally indicate that <span class="hlt">vent</span> biogeography is more complex than previously recognised. PMID:22235194</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMOS11B1488T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMOS11B1488T"><span id="translatedtitle">First <span class="hlt">hydrothermal</span> active <span class="hlt">vent</span> discovered on the Galapagos Microplate</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tao, C.; Li, H.; Wu, G.; Su, X.; Zhang, G.; Chinese DY115-21 Leg 3 Scientific Party</p> <p>2011-12-01</p> <p>The Galapagos Microplate (GM) lies on the western Gaplapagos Spreading Center (GSC), representing one of the classic Ridge-Ridge-Ridge (R-R-R) plate boundaries of the Nazca, Cocos, and Pacific plates. The presence of the 'black smoke' and <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> community were firstly confirmed on the GSC. Lots of <span class="hlt">hydrothermal</span> fields were discovered on the center and eastern GSC, while the western GSC has not been well investigated. During 17th Oct. to 9th Nov. 2009, the 3rd leg of Chinese DY115-21 cruise with R/V Dayangyihao has been launched along 2°N-5°S near equatorial East Pacific Rise (EPR). Two new <span class="hlt">hydrothermal</span> fields were confirmed. One is named 'Precious Stone Mountain', which is the first <span class="hlt">hydrothermal</span> field on the GM. The other is found at 101.47°W, 0.84°S EPR. The 'Precious Stone Mountain' <span class="hlt">hydrothermal</span> field (at 101.49°W, 1.22°N) is located at an off-axial seamount on the southern GM boundary, with a depth from 1,450 to 1,700m. <span class="hlt">Hydrothermal</span> fluids emitting from the fissures and <span class="hlt">hydrothermal</span> fauna were captured by deep-tow video. Few mineral clasts of pyrite and chalcopyrite were separated from one sediment sample, but no sulfide chimney was found yet. <span class="hlt">Hydrothermal</span> fauna such as alive mussels, crabs, shrimps, tubeworms, giant clams, as well as rock samples were collected by TV-Grab. The study of the seafloor classification with Simrad EM120 multi-beam echosounder has been conducted on the 'Precious Stone Mountain' <span class="hlt">hydrothermal</span> field. The result indicates that seafloor materials around the <span class="hlt">hydrothermal</span> field can be characterized into three types, such as the fresh lava, <span class="hlt">hydrothermal</span> sediment, and altered rock.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.oeb.harvard.edu/faculty/girguis/pdf/2010ChildressMetabolic.pdf','EPRINT'); return false;" href="http://www.oeb.harvard.edu/faculty/girguis/pdf/2010ChildressMetabolic.pdf"><span id="translatedtitle">Introduction The deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> communities were discovered in</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Girguis, Peter R.</p> <p></p> <p>312 Introduction The deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> communities were discovered in 1977 and immediately. The physiological functioning of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> species, especially R. pachyptila, was studied intensively also been found. Early on in <span class="hlt">vent</span> research it was apparent that the giant tubeworm, Riftia pachyptila</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.B13A0164P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.B13A0164P"><span id="translatedtitle">Sulfate Reduction and Sulfide Biomineralization By Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Microorganisms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Picard, A.; Gartman, A.; Clarke, D. R.; Girguis, P. R.</p> <p>2014-12-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are characterized by steep temperature and chemical gradients and moderate pressures. At these <span class="hlt">sites</span>, mesophilic sulfate-reducing bacteria thrive, however their significance for the formation of sulfide minerals is unknown. In this study we investigated sulfate reduction and sulfide biomineralization by the deep-sea bacterium Desulfovibrio hydrothermalis isolated from a deep-sea <span class="hlt">vent</span> chimney at the Grandbonum <span class="hlt">vent</span> <span class="hlt">site</span> (13°N, East Pacific Rise, 2600 m water depth) [1]. Sulfate reduction rates were determined as a function of pressure and temperature. Biomineralization of sulfide minerals in the presence of various metal concentrations was characterized using light and electron microscopy and optical spectroscopy. We seek to better understand the significance of biological sulfate reduction in deep-sea <span class="hlt">hydrothermal</span> environments, to characterize the steps in sulfide mineral nucleation and growth, and identify the interactions between cells and minerals. [1] D. Alazard, S. Dukan, A. Urios, F. Verhe, N. Bouabida, F. Morel, P. Thomas, J.L. Garcia and B. Ollivier, Desulfovibrio hydrothermalis sp. nov., a novel sulfate-reducing bacterium isolated from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, Int. J. Syst. Evol. Microbiol., 53 (2003) 173-178.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ipgp.fr/~kaminski/web_doudoud/height_gui.pdf','EPRINT'); return false;" href="http://www.ipgp.fr/~kaminski/web_doudoud/height_gui.pdf"><span id="translatedtitle">On the rise of turbulent plumes: Quantitative effects of variable entrainment for submarine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, terrestrial</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Kaminski, Edouard</p> <p></p> <p><span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, terrestrial and extra terrestrial explosive volcanism G. Carazzo,1 E. Kaminski,1 and S: Quantitative effects of variable entrainment for submarine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, terrestrial and extra terrestrial, paleo-Martian, and Venusian conditions and by submarine <span class="hlt">hydrothermal</span> activity at mid-ocean ridges</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://xraysweb.lbl.gov/uxas/Publicatons/Papers/pdfs/Toner%20et%20al%202008%20JdR%20biogenic%20FeGeneric.pdf','EPRINT'); return false;" href="http://xraysweb.lbl.gov/uxas/Publicatons/Papers/pdfs/Toner%20et%20al%202008%20JdR%20biogenic%20FeGeneric.pdf"><span id="translatedtitle">Biogenic iron oxyhydroxide formation at mid-ocean ridge <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>: Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p></p> <p></p> <p>Biogenic iron oxyhydroxide formation at mid-ocean ridge <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>: Juan de Fuca Ridge kgÀ1 (German and von Damm, 2004). As <span class="hlt">vented</span> <span class="hlt">hydrothermal</span> fluids mix with cold, oxygenated deep in mid-ocean ridge (MOR) <span class="hlt">hydrothermal</span> end-member fluids at concentrations ranging from 0.007 to 25 mmol</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://geoscience.wisc.edu/ICP-TIMS/wp-content/uploads/2015/08/Chu_et_al_2006_EPSL.pdf','EPRINT'); return false;" href="http://geoscience.wisc.edu/ICP-TIMS/wp-content/uploads/2015/08/Chu_et_al_2006_EPSL.pdf"><span id="translatedtitle">Evidence for <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> in Fe isotope compositions of the deep Pacific Ocean through time</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Johnson, Clark M.</p> <p></p> <p>Evidence for <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> in Fe isotope compositions of the deep Pacific Ocean through time ocean may have lower 56 Fe values than those measured so far in situ at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Correlation <span class="hlt">hydrothermal</span> input and increased growth rates. A second crust located within 100 km of the first IB sample does</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.oeb.harvard.edu/faculty/girguis/pdf/2013RobidartCallisterSongNicoraWheatGirguisENVSCITECH.pdf','EPRINT'); return false;" href="http://www.oeb.harvard.edu/faculty/girguis/pdf/2013RobidartCallisterSongNicoraWheatGirguisENVSCITECH.pdf"><span id="translatedtitle">Characterizing Microbial Community and Geochemical Dynamics at <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> Using Osmotically Driven Continuous Fluid</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Girguis, Peter R.</p> <p></p> <p>Characterizing Microbial Community and Geochemical Dynamics at <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> Using Osmotically.5 year laboratory study as well as the results of two field deployments at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> data reveal marked changes in microbial composition co-occurring with changes in <span class="hlt">hydrothermal</span> fluid</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.people.fas.harvard.edu/~langmuir/Bakeretal'04.pdf','EPRINT'); return false;" href="http://www.people.fas.harvard.edu/~langmuir/Bakeretal'04.pdf"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">venting</span> in magma deserts: The ultraslow-spreading Gakkel and Southwest Indian Ridges</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Langmuir, Charles H.</p> <p></p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">venting</span> in magma deserts: The ultraslow- spreading Gakkel and Southwest Indian Ridges of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span>, but the validity of this relation at slow and ultraslow ridges is unproved. Here we, Massachusetts 02138, USA (langmuir@eps.harvard.edu) [1] Detailed <span class="hlt">hydrothermal</span> surveys over ridges with spreading</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DSRII.121...85B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DSRII.121...85B"><span id="translatedtitle">The importance of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> to water-column secondary production in the northeast Pacific</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burd, Brenda J.; Thomson, Richard E.</p> <p>2015-11-01</p> <p>The purpose of this study is to show that seafloor <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> in the open northeast Pacific Ocean has a marked impact on secondary biomass and production within the overlying water column. Specifically, we use net tows and concurrently measured acoustic backscatter data collected over six summers to examine the effects of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> from the Endeavour Segment of Juan de Fuca Ridge on macro-zooplankton biomass and production throughout the entire 2000 m depth range. Previous research shows that ontogenetic diapausing migrators and their predators from the upper ocean aggregate above the neutrally buoyant plumes in summer and resume feeding on plume and bottom upwelled particles, resulting in increased zooplankton reproductive output to the upper ocean. Within the limitations of our sampling methodology, net tows reveal a statistically significant exponential decline in total water-column biomass with increasing lateral distance from the <span class="hlt">vent</span> fields. The acoustic backscatter data show a similar decline, but only below 800 m depth. Near-surface biomass was highly variable throughout the region, but values near <span class="hlt">vents</span> consistently ranged higher than summer values found elsewhere in the offshore northeast Pacific. Water-column biomass was similar in magnitude above and below 800 m depth throughout the region. Because epiplume biomass can be advected a considerable distance from <span class="hlt">vent</span> fields, biomass enhancement of the water column from <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> may extend considerable distances to the west and northwest of the <span class="hlt">vent</span> <span class="hlt">sites</span>, in the prevailing directions of the subsurface flow. Based on the extensive acoustic Doppler current profiler (ADCP) data collected, and the strong correlation between zooplankton production derived from net sample biomass and acoustic backscatter intensity, we estimate that daily macro-zooplankton production in the upper 400 m of the water column within 10 km of the <span class="hlt">vent</span> fields averages approximately 16% of photosynthetic primary production (the "Z ratio"), whereas the total water-column zooplankton production averages 26% of surface primary production. Local grazing-rate estimates, metabolic constraints and other open-ocean studies suggest that the Z ratio should be no higher than 5%, which it is at off-axis background <span class="hlt">sites</span> in the study region. This finding indicates that nutrient sources other than upper-ocean primary production fuel both upper- and deep-ocean zooplankton biomass and growth near the Endeavour Ridge <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DSRII.121..193G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DSRII.121..193G"><span id="translatedtitle">Variation in the diets of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> gastropods</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Govenar, Breea; Fisher, Charles R.; Shank, Timothy M.</p> <p>2015-11-01</p> <p>A prevailing paradigm of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecology is that primary consumers feed on chemoautotrophic bacteria. However, for the purposes of reconstructing <span class="hlt">vent</span> food webs and for tracking energy flow from the generation of rock and fluid chemistry through primary/ secondary productivity and consumption to the overlying water column, it remains unclear which consumers feed on which bacteria. In paired analyses of carbon and nitrogen tissue stable isotope values with unique 16S rRNA sequences from the stomach contents, we determined that two species of gastropod grazers appear to feed on epsilon-proteobacteria, while two other species have more diverse diets, including one species that consumes alpha-proteobacteria, planctomycetes, and non-green sulfur bacteria. Different carbon fixation pathways used by epsilon- and alpha-proteobacteria may account for the variation in the carbon stable isotope values among the consumers. Furthermore, our results indicate that trophic specialization and niche partitioning may contribute to the distribution and abundance of <span class="hlt">vent</span>-endemic gastropods and support the hypothesis that consumers in the warmer habitats commonly feed on epsilon-proteobacteria that use the rTCA cycle, while in the cooler habitats they feed on additional bacteria that use the CBB cycle. These results suggest that the phylogenetic and metabolic diversity of free-living bacteria may play an important and previously overlooked role in facilitating species coexistence among primary consumers at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> and other chemosynthesis-based ecosystems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/8472894','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/8472894"><span id="translatedtitle">Aspects of life development at deep sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gaill, F</p> <p>1993-04-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> organisms are living in an unexpected deep-sea environment, several thousand meters below the surface, where the earth's crustal plates are spreading apart. The <span class="hlt">vent</span> fluids are usually hot (350 degrees C), anoxic, and contain high concentrations of hydrogen sulfide. This environment may be considered as extreme given the pressure, the high temperature, the chemical toxicity of the fluids, and the total lack of photosynthetic production for animal nutrition. The recent discovery of the unique fauna of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> communities has brought an unexpected mode of animal nutrition in which chemoautotrophic bacterial symbionts are maintained within specialized cells of the host animal. The bacterial symbionts obtain energy by oxidizing reduced sulfur compounds from the environment. A portion of this fixed carbon is used by the eukaryotic host. The present review will focus on four of the main topics studied on the paradigmatic <span class="hlt">vent</span> organism Riftia pachyptila, a giant gutless tube worm: 1) the chemoautotrophic symbiosis, 2) the toxicity of hydrogen sulfide, 3) the characteristics of the extracellular matrices of the worms, especially data obtained on collagens, and 4) the influence of temperature and pressure on worm biology. PMID:8472894</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS13A1715S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS13A1715S"><span id="translatedtitle">Biodiversity and biogeography of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> species in the western Pacific: a biological perspective of TAIGA project</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seo, M.; Watanabe, H.; Nakamura, M.; Sasaki, T.; Ogura, T.; Yahagi, T.; Takahashi, Y.; Ishibashi, J.; Kojima, S.</p> <p>2012-12-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are scientifically interesting environments where strong interactions of geology, chemistry, and biology can be observed. The <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are geologically controlled in association with magmatic activities while diversity of chemicals (such as hydrogen sulfide) contained in <span class="hlt">hydrothermal</span> fluid is controlled by geochemical interaction between heated seawater and surrounding rocks. In addition to those geological and chemical characters of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, high biomasses of chemosynthetic community have been known around many <span class="hlt">vents</span> since the first discovery in the 1970s. To understand the unique system and diversity of biological communities associated with <span class="hlt">vents</span> is highly valuable in geological, chemical, and biological sciences. As an activity of the research project "TAIGA (Trans-crustal Advection & In-situ bio-geochemical processes of Global sub-seafloor Aquifer)" (Representative: Tetsuro Urabe, Department of Earth & Planetary Science, the University of Tokyo), we analyzed population structures and connectivity as well as larval ecology of various <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> species in the Okinawa Trough and the Mariana Trough in an attempt to estimate faunal transitional history associated with <span class="hlt">hydrothermal</span> activities. The specimens analyzed in the present study were collected by R/V Yokosuka with manned submersible Shinkai6500 and R/V Natsushima with ROV Hyper-Dolphin during YK10-11 and NT11-20 cruises, respectively. In the Mariana Trough (YK10-11), benthic and planktonic faunas were investigated by multiple sampling and use of plankton samplers in three <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> (Snail, Archaean, and Urashima-Pika fields). Faunal compositions were then compared as well as size compositions and genetic diversities of major <span class="hlt">vent</span> species among local populations. In the Okinawa Trough (NT11-20), multiple quantitative sampling was made with simultaneous environmental measurements at more than two <span class="hlt">sites</span> in five <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> (Minami-Ensei Knoll, Yoron Knoll, Izena Hole, Irabu Knoll, and Hatoma Knoll). Among the local populations, biodiversities were analyzed and compared in consideration of abiotic environmental factors including temperature and chemical compositions. Ecological aspects of larvae were examined by laboratory experiments in addition to the genetic approaches and population dynamics. Preliminary results of the ongoing studies suggested that the biodiversity of <span class="hlt">vents</span> may be consistent with geographical history. By accumulating results of diversified approaches, we progress our study to reveal not only biological characters but also geological and chemical aspects of those <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DSRI..106..167G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DSRI..106..167G"><span id="translatedtitle">Differences in recovery between deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> and <span class="hlt">vent</span>-proximate communities after a volcanic eruption</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gollner, Sabine; Govenar, Breea; Arbizu, Pedro Martinez; Mills, Susan; Le Bris, Nadine; Weinbauer, Markus; Shank, Timothy M.; Bright, Monika</p> <p>2015-12-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> and the surrounding basalt seafloor are subject to major natural disturbance events such as volcanic eruptions. In the near future, anthropogenic disturbance in the form of deep-sea mining could also significantly affect the faunal communities of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. In this study, we monitor and compare the recovery of insular, highly productive <span class="hlt">vent</span> communities and <span class="hlt">vent</span>-proximate basalt communities following a volcanic eruption that destroyed almost all existing communities at the East Pacific Rise, 9°50?N in 2006. To study the recovery patterns of the benthic communities, we placed settlement substrates at <span class="hlt">vent</span> <span class="hlt">sites</span> and their proximate basalt areas and measured the prokaryotic abundance and compared the meio- and macrofaunal species richness and composition at one, two and four years after the eruption. In addition, we collected samples from the overlying water column with a pelagic pump, at one and two years after the volcanic eruption, to determine the abundance of potential meiofauna colonisers. One year after eruption, mean meio- and macrofaunal abundances were not significantly different from pre-eruption values in <span class="hlt">vent</span> habitats (meio: 8-1838 ind. 64 cm-2 in 2006; 3-6246 ind. 64 cm-2 in 2001/02; macro: 95-1600 ind. 64 cm-2 in 2006; 205-4577 ind. 64 cm-2 in 2001/02) and on non-<span class="hlt">vent</span> basalt habitats (meio: 10-1922 ind. 64 cm-2 in 2006; 8-328 ind. 64 cm-2 in 2003/04; macro: 14-3351 ind. 64 cm-2 in 2006; 2-63 ind. 64 cm-2 in 2003/04), but species recovery patterns differed between the two habitat types. In the <span class="hlt">vent</span> habitat, the initial community recovery was relatively quick but incomplete four years after eruption, which may be due to the good dispersal capabilities of <span class="hlt">vent</span> endemic macrofauna and <span class="hlt">vent</span> endemic dirivultid copepods. At <span class="hlt">vents</span>, 42% of the pre-eruption meio- and 39% of macrofaunal species had returned. In addition, some new species not evident prior to the eruption were found. At the tubeworm <span class="hlt">site</span> Tica, a total of 26 meio- and 19 macrofaunal species were found in 2009, which contrasts with the 24 meio- and 29 macrofauna species detected at the <span class="hlt">site</span> in 2001/02. In the basalt habitat, community recovery of meiofauna was slower with only 28% of the original 64 species present four years after eruption. The more limited dispersal capabilities of meiofauna basalt specialists such as nematodes or harpacticoid copepods probably caused this pattern. In contrast, 67% of the original 27 macrofaunal species had recolonized the basalt by 2009. Our results suggest that not only <span class="hlt">vent</span> communities, but also species-rich communities of <span class="hlt">vent</span>-proximate habitats require attention in conservation efforts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20975681','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20975681"><span id="translatedtitle">Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> animals seek cool fluids in a highly variable thermal environment.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bates, Amanda E; Lee, Raymond W; Tunnicliffe, Verena; Lamare, Miles D</p> <p>2010-01-01</p> <p>The thermal characteristics of an organism's environment affect a multitude of parameters, from biochemical to evolutionary processes. <span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> on mid-ocean ridges are created when warm <span class="hlt">hydrothermal</span> fluids are ejected from the seafloor and mixed with cold bottom seawater; many animals thrive along these steep temperature and chemical gradients. Two-dimensional temperature maps at <span class="hlt">vent</span> <span class="hlt">sites</span> have demonstrated order of magnitude thermal changes over centimetre distances and at time intervals from minutes to hours. To investigate whether animals adapt to this extreme level of environmental variability, we examined differences in the thermal behaviour of mobile invertebrates from aquatic habitats that vary in thermal regime. <span class="hlt">Vent</span> animals were highly responsive to heat and preferred much cooler fluids than their upper thermal limits, whereas invertebrates from other aquatic environments risked exposure to warmer temperatures. Avoidance of temperatures well within their tolerated range may allow <span class="hlt">vent</span> animals to maintain a safety margin against rapid temperature fluctuations and concomitant toxicity of <span class="hlt">hydrothermal</span> fluids. PMID:20975681</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dspace.mit.edu/handle/1721.1/97337','EPRINT'); return false;" href="http://dspace.mit.edu/handle/1721.1/97337"><span id="translatedtitle">Geochemistry of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids from the Mid-Cayman Rise, Caribbean Sea</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>McDermott, Jill Marie</p> <p>2015-01-01</p> <p>This thesis examines the controls on organic, inorganic, and volatile species distributions in <span class="hlt">hydrothermal</span> fluids <span class="hlt">venting</span> at Von Damm and Piccard, two recently discovered <span class="hlt">vent</span> fields at the ultra slow spreading Mid-Cayman ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25602032','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25602032"><span id="translatedtitle">Evolutionary and biogeographical patterns of barnacles from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Herrera, Santiago; Watanabe, Hiromi; Shank, Timothy M</p> <p>2015-02-01</p> <p>The characterization of evolutionary and biogeographical patterns is of fundamental importance to identify factors driving biodiversity. Due to their widespread but discontinuous distribution, deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> barnacles represent an excellent model for testing biogeographical hypotheses regarding the origin, dispersal and diversity of modern <span class="hlt">vent</span> fauna. Here, we characterize the global genetic diversity of <span class="hlt">vent</span> barnacles to infer their time of radiation, place of origin, mode of dispersal and diversification. Our approach was to target a suite of multiple loci in samples representing seven of the eight described genera. We also performed restriction-<span class="hlt">site</span> associated DNA sequencing on individuals from each species. Phylogenetic inferences and topology hypothesis tests indicate that <span class="hlt">vent</span> barnacles have colonized deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> at least twice in history. Consistent with preliminary estimates, we find a likely radiation of barnacles in <span class="hlt">vent</span> ecosystems during the Cenozoic. Our analyses suggest that the western Pacific was the place of origin of the major <span class="hlt">vent</span> barnacle lineage, followed by circumglobal colonization eastwards through the Southern Hemisphere during the Neogene. The inferred time of radiation rejects the classic hypotheses of antiquity of <span class="hlt">vent</span> taxa. The timing and the mode of origin, radiation and dispersal are consistent with recent inferences made for other deep-sea taxa, including nonvent species, and are correlated with the occurrence of major geological events and mass extinctions. Thus, we suggest that the geological processes and dispersal mechanisms discussed here can explain the current distribution patterns of many other marine taxa and have played an important role shaping deep-sea faunal diversity. These results also constitute the critical baseline data with which to assess potential effects of anthropogenic disturbances on deep-sea ecosystems. PMID:25602032</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008DSRI...55.1718P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008DSRI...55.1718P"><span id="translatedtitle">Vertebrate nutrition in a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystem: Fatty acid and stable isotope evidence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pond, D. W.; Fallick, A. E.; Stevens, C. J.; Morrison, D. J.; Dixon, D. R.</p> <p>2008-12-01</p> <p>The <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> zoarcid fish Thermarces cerberus is a top predator that inhabits deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the East Pacific Rise (EPR). Bacterial chemoautotrophy at these <span class="hlt">sites</span> supports abundant animal communities. Paradoxically, these chemoautotrophic bacteria are not known to produce polyunsaturated fatty acids (PUFA), dietary nutrients essential for all marine vertebrates. To understand how T. cerberus successfully exploits the <span class="hlt">vent</span> environment and obtains essential PUFA, we compared its fatty acid composition to those of its invertebrate prey. Levels of 20:5(n-3) and 22:6(n-3) in muscle and ovary tissues of T. cerberus were low and contained higher amounts of 20:5(n-3) than 22:6(n-3). This is in contrast to most marine fish where 22:6(n-3) typically dominates. Prey items include the limpet ( Lepetodrilus elevatus) and amphipods ( Halice hesmonectes and Ventiella sulfuris) and all contained PUFA dominated by 20:5(n-3) in amounts likely to support the requirements of T. cerberus. ?C13 values of 20:5(n-3) in the invertebrate prey were consistent with synthesis from a chemoautotrophic carbon source within the <span class="hlt">vent</span> environment. The potential origins of these PUFA are discussed in terms of the nutrition of T. cerberus and more generally in terms of the evolution of <span class="hlt">vent</span> taxa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dspace.mit.edu/handle/1721.1/89405','EPRINT'); return false;" href="http://dspace.mit.edu/handle/1721.1/89405"><span id="translatedtitle">Metatranscriptomics reveal differences in in situ energy and nitrogen metabolism among <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> snail symbionts</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Sanders, J. G.</p> <p></p> <p>Despite the ubiquity of chemoautotrophic symbioses at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, our understanding of the influence of environmental chemistry on symbiont metabolism is limited. Transcriptomic analyses are useful for linking ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dspace.mit.edu/handle/1721.1/39159','EPRINT'); return false;" href="http://dspace.mit.edu/handle/1721.1/39159"><span id="translatedtitle">Geochemistry of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids from the northern Juan De Fuca Ridge</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Cruse, Anna M. (Anna Marie)</p> <p>2003-01-01</p> <p>The presence of aqueous organic compounds derived from sedimentary organic matter has the potential to influence a range of chemical processes in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments. For example, <span class="hlt">hydrothermal</span> alteration experiments ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dspace.mit.edu/handle/1721.1/65300','EPRINT'); return false;" href="http://dspace.mit.edu/handle/1721.1/65300"><span id="translatedtitle">Reproductive traits of pioneer gastropod species colonizing deep-see <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> after an eruption</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Bayer, Skylar (Skylar Rae)</p> <p>2011-01-01</p> <p>The colonization dynamics and life histories of pioneer species are vital components in understanding the early succession of nascent <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. The reproductive ecology of pioneer species at deep-sea <span class="hlt">hydrothermal</span> ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006DSRI...53.1363Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006DSRI...53.1363Z"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> meiobenthos associated with mytilid mussel aggregations from the Mid-Atlantic Ridge and the East Pacific Rise</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zekely, J.; Van Dover, C. L.; Nemeschkal, H. L.; Bright, M.</p> <p>2006-08-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> occur along the mid-ocean ridges and back-arc basins around the globe. There are very few community analyses of <span class="hlt">vent</span> meiobenthos. The central objectives of this study were to identify and quantify for the first time the entire metazoan meiobenthic community associated with mussel aggregations of Bathymodiolus thermophilus Kenk and Wilson, 1985 from the EPR, 11°N and of Bathymodiolus puteoserpentis Cosel et al., 1994 from the Mid-Atlantic Ridge (MAR), 23°N. Using a quantitative sampling method, abundance, biomass, sex ratio, species richness, diversity, evenness, and trophic structure were studied based on three samples from each <span class="hlt">site</span>. Meiobenthic abundance in each sample was unexpectedly low, but similar between <span class="hlt">sites</span>. The community was composed of nematodes, copepods, ostracods, and mites, with a total of 24 species at EPR <span class="hlt">vents</span>, and 15 species at MAR <span class="hlt">vents</span>. While most copepod species were <span class="hlt">vent</span> endemics within the family Dirivultidae, nematodes and harpacticoid copepods belonged to generalist genera, which occur at a variety of habitats and are not restricted to <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> or the deep sea. The meiobenthos of <span class="hlt">hydrothermal-vent</span> mussel beds constitutes a unique community unlike those of other sulfidic habitats, including the thiobios of shallow-water sediments and the meiobenthos of deep-sea, cold-seep sediments. The trophic structure was dominated by primary consumers, mainly deposit feeders, followed by parasites. Predatory meiofaunal species were absent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3746894','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3746894"><span id="translatedtitle">Reactivity landscape of pyruvate under simulated <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> conditions</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Novikov, Yehor; Copley, Shelley D.</p> <p>2013-01-01</p> <p>Pyruvate is an important “hub” metabolite that is a precursor for amino acids, sugars, cofactors, and lipids in extant metabolic networks. Pyruvate has been produced under simulated <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> conditions from alkyl thiols and carbon monoxide in the presence of transition metal sulfides at 250 °C [Cody GD et al. (2000) Science 289(5483):1337–1340], so it is plausible that pyruvate was formed in <span class="hlt">hydrothermal</span> systems on the early earth. We report here that pyruvate reacts readily in the presence of transition metal sulfide minerals under simulated <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids at more moderate temperatures (25–110 °C) that are more conducive to survival of biogenic molecules. We found that pyruvate partitions among five reaction pathways at rates that depend upon the nature of the mineral present; the concentrations of H2S, H2, and NH4Cl; and the temperature. In most cases, high yields of one or two primary products are found due to preferential acceleration of certain pathways. Reactions observed include reduction of ketones to alcohols and aldol condensation, both reactions that are common in extant metabolic networks. We also observed reductive amination to form alanine and reduction to form propionic acid. Amino acids and fatty acids formed by analogous processes may have been important components of a protometabolic network that allowed the emergence of life. PMID:23872841</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMOS21A1469R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS21A1469R"><span id="translatedtitle">Cameras on the NEPTUNE Canada seafloor observatory: Towards monitoring <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystem dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Robert, K.; Matabos, M.; Sarrazin, J.; Sarradin, P.; Lee, R. W.; Juniper, K.</p> <p>2010-12-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> environments are among the most dynamic benthic habitats in the ocean. The relative roles of physical and biological factors in shaping <span class="hlt">vent</span> community structure remain unclear. Undersea cabled observatories offer the power and bandwidth required for high-resolution, time-series study of the dynamics of <span class="hlt">vent</span> communities and the physico-chemical forces that influence them. The NEPTUNE Canada cabled instrument array at the Endeavour <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> provides a unique laboratory for researchers to conduct long-term, integrated studies of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystem dynamics in relation to environmental variability. Beginning in September-October 2010, NEPTUNE Canada (NC) will be deploying a multi-disciplinary suite of instruments on the Endeavour Segment of the Juan de Fuca Ridge. Two camera and sensor systems will be used to study ecosystem dynamics in relation to <span class="hlt">hydrothermal</span> discharge. These studies will make use of new experimental protocols for time-series observations that we have been developing since 2008 at other observatory <span class="hlt">sites</span> connected to the VENUS and NC networks. These protocols include sampling design, camera calibration (i.e. structure, position, light, settings) and image analysis methodologies (see communication by Aron et al.). The camera systems to be deployed in the Main Endeavour <span class="hlt">vent</span> field include a Sidus high definition video camera (2010) and the TEMPO-mini system (2011), designed by IFREMER (France). Real-time data from three sensors (O2, dissolved Fe, temperature) integrated with the TEMPO-mini system will enhance interpretation of imagery. For the first year of observations, a suite of internally recording temperature probes will be strategically placed in the field of view of the Sidus camera. These installations aim at monitoring variations in <span class="hlt">vent</span> community structure and dynamics (species composition and abundances, interactions within and among species) in response to changes in environmental conditions at different temporal scales. High-resolution time-series studies also provide a mean of studying population dynamics, biological rhythms, organism growth and faunal succession. In addition to programmed time-series monitoring, the NC infrastructure will also permit manual and automated modification of observational protocols in response to natural events. This will enhance our ability to document potentially critical but short-lived environmental forces affecting <span class="hlt">vent</span> communities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1616710Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1616710Y"><span id="translatedtitle">Dynamic drivers of a shallow-water <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecogeochemical system (Milos, Eastern Mediterranean)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yücel, Mustafa; Sievert, Stefan; Giovanelli, Donato; Foustoukos, Dionysis; DeForce, Emelia; Thomas, François; Vetriani, Constantino; Le Bris, Nadine</p> <p>2014-05-01</p> <p>Shallow-water <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> share many characteristics with their deep-sea analogs. However, despite ease of access, much less is known about the dynamics of these systems. Here, we report on the spatial and temporal chemical variability of a shallow-water <span class="hlt">vent</span> system at Paleochori Bay, Milos Island, Greece, and on the bacterial and archaeal diversity of associated sandy sediments. Our multi-analyte voltammetric profiles of dissolved O2 and <span class="hlt">hydrothermal</span> tracers (e.g. Fe2+, FeSaq, Mn2+) on sediment cores taken along a transect in <span class="hlt">hydrothermally</span> affected sediments indicate three different areas: the central <span class="hlt">vent</span> area (highest temperature) with a deeper penetration of oxygen into the sediment, and a lack of dissolved Fe2+ and Mn2+; a middle area (0.5 m away) rich in dissolved Fe2+ and Mn2+ (exceeding 2 mM) and high free sulfide with potential for microbial sulfide oxidation as suggested by the presence of white mats at the sediment surface; and, finally, an outer rim area (1-1.5 m away) with lower concentrations of Fe2+ and Mn2+ and higher signals of FeSaq, indicating an aged <span class="hlt">hydrothermal</span> fluid contribution. In addition, high-frequency temperature series and continuous in situ H2S measurements with voltammetric sensors over a 6-day time period at a distance 0.5 m away from the <span class="hlt">vent</span> center showed substantial temporal variability in temperature (32 to 46 ºC ) and total sulfide (488 to 1329 µM) in the upper sediment layer. Analysis of these data suggests that tides, winds, and abrupt geodynamic events generate intermittent mixing conditions lasting for several hours to days. Despite substantial variability, the concentration of sulfide available for chemoautotrophic microbes remained high. These findings are consistent with the predominance of Epsilonproteobacteria in the <span class="hlt">hydrothermally</span> influenced sediments Diversity and metagenomic analyses on sediments and biofilm collected along a transect from the center to the outer rim of the <span class="hlt">vent</span> provide further insights on the metabolic activities and the environmental factors shaping these microbial communities . Both bacterial and archaeal diversity changed along the transect as well as with sediment depth, in line with the geochemical measurements. Beside the fact that it harbors an unexpected diversity of yet undescribed bacteria and archaea, this <span class="hlt">site</span> is also a relevant model to investigate the link between ecological and abiotic dynamics in such instable <span class="hlt">hydrothermal</span> environments. Our results provide evidence for the importance of transient geodynamic and hydrodynamic events in the dynamics and distribution of chemoautotrophic communities in the <span class="hlt">hydrothermally</span> influenced sediments of Paleochori Bay.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18201197','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18201197"><span id="translatedtitle">Temporal and spatial archaeal colonization of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> deposits.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Pagé, Antoine; Tivey, Margaret K; Stakes, Debra S; Reysenbach, Anna-Louise</p> <p>2008-04-01</p> <p>Thermocouple arrays were deployed on two deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> at Guaymas Basin (27 degrees 0.5'N, 111 degrees 24.5'W) in order to measure in situ temperatures at which microorganisms colonize the associated mineral deposits. Intact sections of three structures that formed around the arrays were collected after 4 and 72 day deployments (named BM4, BM72 and TS72). Archaeal diversity associated with discreet subsamples collected across each deposit was determined by polymerase chain reaction amplification of 16S rRNA genes. Spatial differences in archaeal diversity were observed in all deposits and appeared related to in situ temperature. In BM4, no 16S rRNA genes were detected beyond about 1.5 cm within the sample (> 200 degrees C). Phylotypes detected on the outside of this deposit belong to taxonomic groups containing mesophiles and (hyper)thermophiles, whereas only putative hyperthermophiles were detected 1.5 cm inside the structure (approximately 110 degrees C). In contrast, the more moderate thermal gradient recorded across TS72 was associated with a deeper colonization (2-3 cm inside the deposit) of putative hyperthermophilic phylotypes. Although our study does not provide a precise assessment of the highest temperature for the existence of microbial habitats inside the deposits, archaeal 16S rRNA genes were detected directly next to thermocouples that measured 110 degrees C (Methanocaldococcus spp. in BM4) and 116 degrees C (Desulfurococcaceae in TS72). The successive array deployments conducted at the Broken Mushroom (BM) <span class="hlt">site</span> also revealed compositional differences in archaeal communities associated with immature (BM4) and mature chimneys (BM72) formed by the same fluids. These differences suggest a temporal transition in the primary carbon sources used by the archaeal communities, with potential CO(2)/H(2) methanogens prevalent in BM4 being replaced by possible methylotroph or acetoclastic methanogens and heterotrophs in BM72. This study is the first direct assessment of in situ conditions experienced by microorganisms inhabiting actively forming <span class="hlt">hydrothermal</span> deposits at different stages of structure development. PMID:18201197</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMOS43C..01A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMOS43C..01A"><span id="translatedtitle">The influence of surface energy on the transport of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> products and the connections among <span class="hlt">vent</span> populations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adams, D. K.</p> <p>2013-12-01</p> <p>Atmospheric forcing, which is known to have strong influence on surface ocean dynamics and production, is typically not considered in studies of the deep sea. Our observations and models demonstrate an unexpected influence of surface-generated mesoscale eddies originating off the coast of Central America in the transport of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> efflux and of <span class="hlt">vent</span> larvae away from the northern East Pacific Rise and potentially between isolated <span class="hlt">vent</span> fields. These eddies are formed seasonally and are sensitive to phenomena such as El Niño, they have the potential to introduce seasonal to interannual atmospheric variations into the deep sea. The evidence from the northern East Pacific Rise suggests that surface processes may influence transport of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> products more widely. We tested this hypothesis by comparing patterns of connectivity among populations of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> organisms with patterns of ocean surface kinetic energy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6962771','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6962771"><span id="translatedtitle">Chemistry of <span class="hlt">hydrothermal</span> solutions from Pele's <span class="hlt">Vents</span>, Loihi Seamount, Hawaii</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sedwick, P.N.; McMurtry, G.M. ); Macdougall, J.D. )</p> <p>1992-10-01</p> <p><span class="hlt">Hydrothermal</span> fluids were sampled from Pele's <span class="hlt">Vents</span> on the summit of Loihi Seamount, an intraplate, hotspot volcano, on four occasions from February 1987 to September 1990. The warm ([le]31C) <span class="hlt">vent</span> solutions are enriched in dissolved Si, CO[sub 2], H[sub 2]S, alkalinity, K[sup +], Li[sup +], Rb[sup +], Ca[sup 2+], Ba[sup 2+], Fe[sup 2+], Mn[sup 2+], NH[sup +][sub 4], and possibly Ni[sup 2+], and depleted in SO[sup 2-][sub 4], O[sub 2], Mg[sup 2+], [sup 87]Sr/[sup 86]Sr, NO[sup -][sub 3], and sometimes Cl[sup -] and Na[sup +] (calculated), relative to ambient seawater. Dissolved Si correlates linearly with sample temperature, suggesting that the solutions sampled from numerous <span class="hlt">vents</span> in the [approximately]20 m diameter field have a common source and that Si can be used as a conservative tracer for mixing of the <span class="hlt">vent</span> fluids with ambient seawater. These juvenile inputs likely reflect the shallow, hotspot setting of this <span class="hlt">hydrothermal</span> system. A simple quantitative fluid-history model is considered and shown to be consistent with mass-balance constraints and saturation-state calculations, which suggest that the Si concentration of the fluids may be controlled by amorphous silica saturation at [approximately]31C. Observed temporal variations in fluid composition between expeditions - specifically, in Cl[sup -], A[sub T], C[sub T], Na[sup +] (calculated), Mg[sup 2+], Ca[sup 2+], Sr[sup 2+], [sup 87]Sr/[sup 86]Sr, Fe[sup 2+], Mn[sup 2+] and perhaps NH[sup +][sub 4], relative to Si - are, excepting Mg[sup 2+], [sup 87]Sr/[sup 86]Sr, and Mn[sup 2+], consistent with the effects of variable phase segregation at the proposed high-temperature endmember.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17014490','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17014490"><span id="translatedtitle">Off-axis symbiosis found: Characterization and biogeography of bacterial symbionts of Bathymodiolus mussels from Lost City <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>DeChaine, Eric G; Bates, Amanda E; Shank, Timothy M; Cavanaugh, Colleen M</p> <p>2006-11-01</p> <p>Organisms at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> inhabit discontinuous chemical 'islands' along mid-ocean ridges, a scenario that may promote genetic divergence among populations. The 2003 discovery of mussels at the Lost City <span class="hlt">Hydrothermal</span> Field provided a means of evaluating factors that govern the biogeography of symbiotic bacteria in the deep sea. The unusual chemical composition of <span class="hlt">vent</span> fluids, the remote location, and paucity of characteristic <span class="hlt">vent</span> macrofauna at the <span class="hlt">site</span>, raised the question of whether microbial symbioses existed at the extraordinary Lost City. If so, how did symbiotic bacteria therein relate to those hosted by invertebrates at the closest known <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> along the Mid-Atlantic Ridge (MAR)? To answer these questions, we performed microscopic and molecular analyses on the bacteria found within the gill tissue of Bathymodiolus mussels (Mytilidae, Bathymodiolinae) that were discovered at the Lost City. Here we show that Lost City mussels harbour chemoautotrophic and methanotrophic endosymbionts simultaneously. Furthermore, populations of the chemoautotrophic symbionts from the Lost City and two <span class="hlt">sites</span> along the MAR are genetically distinct from each other, which suggests spatial isolation of bacteria in the deep sea. These findings provide new insights into the processes that drive diversification of bacteria and evolution of symbioses at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. PMID:17014490</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://depts.washington.edu/oacis/lp/vents_lesson.pdf','EPRINT'); return false;" href="http://depts.washington.edu/oacis/lp/vents_lesson.pdf"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> Goal of the Lesson Introduce connection between ocean geology and biology,</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Grünbaum, Daniel</p> <p></p> <p>, reinforce concepts taught in plate tectonics. Key Concepts · <span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> occur because of plate different features Time frame: 50 minutes Background · Students should have covered plate tectonics tectonics · <span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> support rich communities of animals · Introduce that the seafloor has many</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70032178','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70032178"><span id="translatedtitle">S-33 constraints on the seawater sulfate contribution in modern seafloor <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> sulfides</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Ono, Shuhei; Shanks, Wayne C., III; Rouxel, O.J.; Rumble, D.</p> <p>2007-01-01</p> <p>Sulfide sulfur in mid-oceanic ridge <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> is derived from leaching of basaltic-sulfide and seawater-derived sulfate that is reduced during high temperature water rock interaction. Conventional sulfur isotope studies, however, are inconclusive about the mass-balance between the two sources because 34S/32S ratios of <span class="hlt">vent</span> fluid H2S and chimney sulfide minerals may reflect not only the mixing ratio but also isotope exchange between sulfate and sulfide. Here, we show that high-precision analysis of S-33 can provide a unique constraint because isotope mixing and isotope exchange result in different ??33S (?????33S-0.515 ??34S) values of up to 0.04??? even if ??34S values are identical. Detection of such small ??33S differences is technically feasible by using the SF6 dual-inlet mass-spectrometry protocol that has been improved to achieve a precision as good as 0.006??? (2??). Sulfide minerals (marcasite, pyrite, chalcopyrite, and sphalerite) and <span class="hlt">vent</span> H2S collected from four active seafloor <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span>, East Pacific Rise (EPR) 9-10??N, 13??N, and 21??S and Mid-Atlantic Ridge (MAR) 37??N yield ??33S values ranging from -0.002 to 0.033 and ??34S from -0.5??? to 5.3???. The combined ??34S and ??33S systematics reveal that 73 to 89% of <span class="hlt">vent</span> sulfides are derived from leaching from basaltic sulfide and only 11 to 27% from seawater-derived sulfate. Pyrite from EPR 13??N and marcasite from MAR 37??N are in isotope disequilibrium not only in ??34S but also in ??33S with respect to associated sphalerite and chalcopyrite, suggesting non-equilibrium sulfur isotope exchange between seawater sulfate and sulfide during pyrite precipitation. Seafloor <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> sulfides are characterized by low ??33S values compared with biogenic sulfides, suggesting little or no contribution of sulfide from microbial sulfate reduction into <span class="hlt">hydrothermal</span> sulfides at sediment-free mid-oceanic ridge systems. We conclude that 33S is an effective new tracer for interplay among seawater, oceanic crust and microbes in subseafloor <span class="hlt">hydrothermal</span> sulfur cycles. ?? 2006 Elsevier Inc. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GGG....16.2661W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GGG....16.2661W"><span id="translatedtitle">Geology, sulfide geochemistry and supercritical <span class="hlt">venting</span> at the Beebe <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Field, Cayman Trough</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Webber, Alexander P.; Roberts, Stephen; Murton, Bramley J.; Hodgkinson, Matthew R. S.</p> <p>2015-09-01</p> <p>The Beebe <span class="hlt">Vent</span> Field (BVF) is the world's deepest known <span class="hlt">hydrothermal</span> system, at 4960 m below sea level. Located on the Mid-Cayman Spreading Centre, Caribbean, the BVF hosts high temperature (˜401°C) "black smoker" <span class="hlt">vents</span> that build Cu, Zn and Au-rich sulfide mounds and chimneys. The BVF is highly gold-rich, with Au values up to 93 ppm and an average Au:Ag ratio of 0.15. Gold precipitation is directly associated with diffuse flow through "beehive" chimneys. Significant mass-wasting of sulfide material at the BVF, accompanied by changes in metal content, results in metaliferous talus and sediment deposits. Situated on very thin (2-3 km thick) oceanic crust, at an ultraslow spreading centre, the <span class="hlt">hydrothermal</span> system circulates fluids to a depth of ˜1.8 km in a basement that is likely to include a mixture of both mafic and ultramafic lithologies. We suggest <span class="hlt">hydrothermal</span> interaction with chalcophile-bearing sulfides in the mantle rocks, together with precipitation of Au in beehive chimney structures, has resulted in the formation of a Au-rich volcanogenic massive sulfide (VMS) deposit. With its spatial distribution of deposit materials and metal contents, the BVF represents a modern day analogue for basalt hosted, Au-rich VMS systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.V72A1292C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.V72A1292C"><span id="translatedtitle">Organic Complexing in Smectite Clay Minerals Under <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Canfield, B. M.; Williams, L. B.; Holloway, J. R.</p> <p>2002-12-01</p> <p>A <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> at the Juan de Fuca ridge was found to contain smectite-rich clay minerals. At <span class="hlt">vent</span> fluid temperatures (300-350°C) smectite quickly reacts to form more stable minerals, such as illite or chlorite, by incorporating metal cations. While similar investigations have assigned the catalytic properties of clays strictly to the surfaces, it is our hypothesis that organic molecules are polymerized in the smectite interlayers during reaction. Upon incorporation of metal cations and primary organic molecules in the expandable interlayer of these clays, gradual changes in the electrochemical environment may catalyze bio-oligomers that are essential components of life. For comparison, we have examined both dioctahedral (montmorillonite; SWy-1) and trioctahedral (saponite) smectite clay minerals which react to illite and chlorite, respectively. An illite standard (IMt-1) has also been examined as a catalyst. Progressive steps in the reaction process have been monitored through <span class="hlt">hydrothermal</span> experimentation simulating seafloor and subseafloor volcanic conditions in welded gold capsules. K-saturated smectite clays were reacted with aqueous 10 M methanol solutions up to six weeks. Reaction progress was monitored weekly. Results suggest that organic complexity increases as a function of mineralogical reaction. While producing some similar complex organic compounds, reactions starting with illite yielded significantly lower product concentrations than those with the smectites, suggesting the expandable interlayers play an important role in catalysis. Organic analyses were performed by GC-MS; clay analyses by x-ray diffraction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://folk.uio.no/hensven/Svensen_etal_GCA_Nitrogen_08.pdf','EPRINT'); return false;" href="http://folk.uio.no/hensven/Svensen_etal_GCA_Nitrogen_08.pdf"><span id="translatedtitle">Nitrogen geochemistry as a tracer of fluid flow in a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> complex in the Karoo Basin, South Africa</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Svensen, Henrik</p> <p></p> <p>Nitrogen geochemistry as a tracer of fluid flow in a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> complex in the Karoo Basin and <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> complexes (HVC) in the Karoo Basin in South Africa. The HVC formed during phreatic eruptions. Bulk-rock N isotope data for rocks from inside and outside the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> com- plex fall</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://alrlab.pdx.edu/media/corre%20et%20al%202001.pdf','EPRINT'); return false;" href="http://alrlab.pdx.edu/media/corre%20et%20al%202001.pdf"><span id="translatedtitle">O-Proteobacterial diversity from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> on the Mid-Atlantic Ridge</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Reysenbach, Anna-Louise</p> <p></p> <p>O-Proteobacterial diversity from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> on the Mid-Atlantic Ridge Erwan Corre with an in situ growth chamber deployed for 5 days on a Mid-Atlantic Ridge <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> (23³22PN, 44³57PW Science B.V. All rights reserved. Keywords: <span class="hlt">Hydrothermal</span> <span class="hlt">vent</span>; Bacterial diversity; Phylogenetic analysis</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840031038&hterms=Hydrothermal+vents&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2528Hydrothermal%2Bvents%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840031038&hterms=Hydrothermal+vents&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2528Hydrothermal%2Bvents%2529"><span id="translatedtitle">Sulphur isotopic compositions of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> animals</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fry, B.; Gest, H.; Hayes, J. M.</p> <p>1983-01-01</p> <p>The S-34/S-32 ratios of tissues from vestimentiferan worms, brachyuran crabs, and giant clams living around deep <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are reported. Clean tissues were dried, ground, suspended in 0.1 M LiCl, shaken twice at 37 C to remove seawater sulfates, dried at 60 C, combusted in O2 in a Parr bomb. Sulfur was recovered as BaSO4, and the isotopic abundances in SO2 generated by thermal decomposition of 5-30-mg samples were determined using an isotope-ratio mass spectrometer. The results are expressed as delta S-34 and compared with values measured in seawater sulfates and in normal marine fauna. The values ranged from -4.7 to 4.7 per thousand, comparable to <span class="hlt">vent</span> sulfide minerals (1.3-4.1 per thousand) and distinct from seawater sulfates (20.1 per thousand) and normal marine fauna (about 13-20 per thousand). These results indicate that <span class="hlt">vent</span> sulfur rather than seawater sulfur is utilized by these animals, a process probably mediated by chemoautotrophic bacteria which can use inorganic sulfur compounds as energy sources.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.P61D..08J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.P61D..08J"><span id="translatedtitle">Simulated Mars Rover Mission to <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span>, Ka'u Desert, Hawai'i</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jolliff, B. L.; Arvidson, R. E.; Doty, A. M.; Davies, N.; de St. Maurice, A.; Griggs, L. E.; Gross, M. E.; Ishida, C. C.; Izsak, G. M.; Deal, K. S.; Snider, N. O.</p> <p>2002-12-01</p> <p>Observations and measurements were made in the field and samples returned for laboratory study from the Ka'u Desert, Hawai'i. The <span class="hlt">site</span> includes recent lava flows and flanking older flows, wind-blown and variably altered ash deposits, and alteration associated with sulfurous volcanic <span class="hlt">vents</span>. The <span class="hlt">site</span> is an analogue for the type being proposed for the NASA Mars Mobile Geobiology Explorer Mission. Experiments and observations included tripod-based color stereo imaging, thermal imaging, and reflectance spectrometry to map topography, thermal properties, and mineralogy associated with flow and ash-deposit alteration stages and <span class="hlt">hydrothermal</span> deposits. Laboratory analyses include mineralogy, elemental compositions, and biological analysis of returned samples for ground truth and for comparison to what can be learned from field observations. Integrated studies include comparison of VIS-IR spectra obtained on the ground and observed lithologic endmembers to remotely sensed data and spectral endmembers (Deal et al., this Conf.), development of a topographic model from stereo imaging, alteration of basalts and relationships between ash deposits and basalts, including formation of duricrusts, thermal imaging and development of a thermal model, and characterization of extant and fossilized biological activity associated with sulfurous <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Analyses to examine active biology at the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> include DNA amplification and identification using PCR (polymerase chain reaction) methods and FISH (fluorescence in-situ hybridization). Morphological evidence of entombment of microbes will be sought in mineralized crusts associated with the <span class="hlt">hydrothermal</span> deposits. Video documentation of field work coupled with results of field observations and laboratory analyses will be used to better understand and define the essential measurements to make during future Mars missions, with implications for procedures and protocols for eventual sample returns.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3265507','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3265507"><span id="translatedtitle">The spatial scale of genetic subdivision in populations of Ifremeria nautilei, a <span class="hlt">hydrothermal-vent</span> gastropod from the southwest Pacific</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2011-01-01</p> <p>Background Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> provide patchy, ephemeral habitats for specialized communities of animals that depend on chemoautotrophic primary production. Unlike eastern Pacific <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, where population structure has been studied at large (thousands of kilometres) and small (hundreds of meters) spatial scales, population structure of western Pacific <span class="hlt">vents</span> has received limited attention. This study addresses the scale at which genetic differentiation occurs among populations of a western Pacific <span class="hlt">vent</span>-restricted gastropod, Ifremeria nautilei. Results We used mitochondrial and DNA microsatellite markers to infer patterns of gene flow and population subdivision. A nested sampling strategy was employed to compare genetic diversity in discrete patches of Ifremeria nautilei separated by a few meters within a single <span class="hlt">vent</span> field to distances as great as several thousand kilometres between back-arc basins that encompass the known range of the species. No genetic subdivisions were detected among patches, mounds, or <span class="hlt">sites</span> within Manus Basin. Although I. nautilei from Lau and North Fiji Basins (~1000 km apart) also exhibited no evidence for genetic subdivision, these populations were genetically distinct from the Manus Basin population. Conclusions An unknown process that restricts contemporary gene flow isolates the Manus Basin population of Ifremeria nautilei from widespread populations that occupy the North Fiji and Lau Basins. A robust understanding of the genetic structure of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> populations at multiple spatial scales defines natural conservation units and can help minimize loss of genetic diversity in situations where human activities are proposed and managed. PMID:22192622</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.3929B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.3929B"><span id="translatedtitle">The influence of <span class="hlt">vent</span> fluid chemistry on trophic structure at two deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields on the Mid-Cayman Rise</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bennett, Sarah; Van Dover, Cindy; Coleman, Max</p> <p>2014-05-01</p> <p>The two known deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields along the Mid-Cayman Rise are separated by a distance of only 21 km, yet their chemistry and faunal diversity are distinct. The deeper of the two <span class="hlt">vent</span> fields, Piccard (with active <span class="hlt">venting</span> from Beebe <span class="hlt">Vents</span>, Beebe Woods and Beebe Sea), at 4980 m is basalt hosted. The shallower <span class="hlt">vent</span> field, Von Damm, at 2300 m appears to have an ultramafic influence. The Von Damm <span class="hlt">vent</span> field can be separated into two <span class="hlt">sites</span>: The Spire and The Tubeworm Field. The dominant <span class="hlt">vent</span> fluids at the Tubeworm Field are distinct from those at the Spire, as a result of fluid modification in the sub-surface. Von Damm and Piccard <span class="hlt">vent</span> fields support abundant invertebrates, sharing the same biomass-dominant shrimp species, Rimicaris hybisae. Although there are some other shared species (squat lobsters (Munidopsis sp.) and gastropods (Provanna sp. and Iheyaspira sp.)) between the <span class="hlt">vent</span> fields, they are much more abundant at one <span class="hlt">site</span> than the other. In this study we have examined the bulk carbon, nitrogen and sulfur isotope composition of microbes and fauna at each <span class="hlt">vent</span> field. With these data we have deduced the trophic structure of the communities and the influence of <span class="hlt">vent</span> fluid chemistry. From stable isotope data and end-member <span class="hlt">vent</span> fluid chemistry, we infer that the basis of the trophic structure at Piccard is dominated by sulfur, iron, and hydrogen-oxidizing microbial communities. In comparison, the basis of the Von Damm trophic structure is dominated by microbial communities of sulfur and hydrogen oxidizers, sulfate reducers and methanotrophs. This microbial diversity at the base of the trophic structure is a result of chemical variations in <span class="hlt">vent</span> fluids and processes in the sub-surface that alter the <span class="hlt">vent</span> fluid chemistry. These differences influence higher trophic levels and can be used to explain some of the variability as well as similarity in fauna at the <span class="hlt">vent</span> <span class="hlt">sites</span>. Part of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with National Aeronautics and Space Administration (NASA).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.V51D1736B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.V51D1736B"><span id="translatedtitle">Denitrification in diffuse <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids of Axial Volcano and the Endeavour Segment on the Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bourbonnais, A.; Lehmann, M. F.; Butterfield, D. A.; Devol, A.; Chang, B. X.; Juniper, K.</p> <p>2009-12-01</p> <p>Denitrification is a major and well-investigated sink of bio-available nitrogen (N) in the ocean. However, little is known about the removal of N in diffuse <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. <span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> fluids are known to harbor diverse bacterial populations, and the use of nitrate as an electron acceptor for the microbially mediated oxidation of hydrogen sulphide has previously been documented in these extreme environments, but no direct measurements of denitrification rates have been reported. We present the first denitrification rate estimates (i.e. the conversion of nitrate to nitrogen gas) derived from 15N-label incubations at 7 diffuse <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> along the Juan de Fuca Ridge (North-East Pacific). Incubation samples (in-situ temperatures between 6.8 and 40.8?C) were collected during research cruises in June and August 2008. We also measured the isotopic composition of nitrate and ammonium from low-T <span class="hlt">sites</span> collected during several cruises from 2006 to 2009. Mixing between ambient seawater and sub-seafloor <span class="hlt">hydrothermal</span> reservoirs is the dominant process that modulates DIN concentration and isotope dynamics. However, clear signs of isotope fractionation of the N (and O of nitrate) isotopes at some <span class="hlt">sites</span> suggests the presence of nitrate consuming processes, likely denitrification and/or the assimilation by <span class="hlt">vent</span> microorganisms. 15N incubation-based denitrification rates ranged from 0 to 0.6 ?M N/day, with no consistent relationship with the in-situ temperature of the <span class="hlt">vent</span> fluids. With only one exception, detectable denitrification rates were determined at all <span class="hlt">sites</span>, suggesting that denitrification is an important N-elimination process in diffuse <span class="hlt">vent</span> fluids. Ongoing work that aims at studying the environmental factors that potentially control rates of denitrification (e.g. temperature, flow rate, fluid chemistry), as well as other possible N removal pathways (e.g. anammox and DNRA coupled to anammox), will also be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1024290','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1024290"><span id="translatedtitle">Microbial community structure of <span class="hlt">hydrothermal</span> deposits from geochemically different <span class="hlt">vent</span> fields along the Mid-Atlantic Ridge</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Flores, Gilberto E; Campbell, James H; Kirshtein, Julie D; Meneghin, Jennifer; Podar, Mircea; Steinberg, Joshua; Seewald, Jeffrey S; Tivey, Margaret Kingston; Voytek, Mary A; Reysenbach, Anna-Louise; Yang, Zamin Koo</p> <p>2011-01-01</p> <p>To evaluate the effects of local fluid geochemistry on microbial communities associated with active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> deposits, we examined the archaeal and bacterial communities of 12 samples collected from two very different <span class="hlt">vent</span> fields: the basalt-hosted Lucky Strike (37 17'N, 32 16.3'W, depth 1600-1750 m) and the ultramafic-hosted Rainbow (36 13'N, 33 54.1'W, depth 2270-2330 m) <span class="hlt">vent</span> fields along the Mid-Atlantic Ridge (MAR). Using multiplexed barcoded pyrosequencing of the variable region 4 (V4) of the 16S rRNA genes, we show statistically significant differences between the archaeal and bacterial communities associated with the different <span class="hlt">vent</span> fields. Quantitative polymerase chain reaction (qPCR) assays of the functional gene diagnostic for methanogenesis (mcrA), as well as geochemical modelling to predict pore fluid chemistries within the deposits, support the pyrosequencing observations. Collectively, these results show that the less reduced, hydrogen-poor fluids at Lucky Strike limit colonization by strict anaerobes such as methanogens, and allow for hyperthermophilic microaerophiles, like Aeropyrum. In contrast, the hydrogen-rich reducing <span class="hlt">vent</span> fluids at the ultramafic-influenced Rainbow <span class="hlt">vent</span> field support the prevalence of methanogens and other hydrogen-oxidizing thermophiles at this <span class="hlt">site</span>. These results demonstrate that biogeographical patterns of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> microorganisms are shaped in part by large scale geological and geochemical processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21418499','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21418499"><span id="translatedtitle">Microbial community structure of <span class="hlt">hydrothermal</span> deposits from geochemically different <span class="hlt">vent</span> fields along the Mid-Atlantic Ridge.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Flores, Gilberto E; Campbell, James H; Kirshtein, Julie D; Meneghin, Jennifer; Podar, Mircea; Steinberg, Joshua I; Seewald, Jeffrey S; Tivey, Margaret Kingston; Voytek, Mary A; Yang, Zamin K; Reysenbach, Anna-Louise</p> <p>2011-08-01</p> <p>To evaluate the effects of local fluid geochemistry on microbial communities associated with active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> deposits, we examined the archaeal and bacterial communities of 12 samples collected from two very different <span class="hlt">vent</span> fields: the basalt-hosted Lucky Strike (37°17'N, 32°16.3'W, depth 1600-1750 m) and the ultramafic-hosted Rainbow (36°13'N, 33°54.1'W, depth 2270-2330 m) <span class="hlt">vent</span> fields along the Mid-Atlantic Ridge (MAR). Using multiplexed barcoded pyrosequencing of the variable region 4 (V4) of the 16S rRNA genes, we show statistically significant differences between the archaeal and bacterial communities associated with the different <span class="hlt">vent</span> fields. Quantitative polymerase chain reaction (qPCR) assays of the functional gene diagnostic for methanogenesis (mcrA), as well as geochemical modelling to predict pore fluid chemistries within the deposits, support the pyrosequencing observations. Collectively, these results show that the less reduced, hydrogen-poor fluids at Lucky Strike limit colonization by strict anaerobes such as methanogens, and allow for hyperthermophilic microaerophiles, like Aeropyrum. In contrast, the hydrogen-rich reducing <span class="hlt">vent</span> fluids at the ultramafic-influenced Rainbow <span class="hlt">vent</span> field support the prevalence of methanogens and other hydrogen-oxidizing thermophiles at this <span class="hlt">site</span>. These results demonstrate that biogeographical patterns of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> microorganisms are shaped in part by large scale geological and geochemical processes. PMID:21418499</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70035670','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70035670"><span id="translatedtitle">Microbial community structure of <span class="hlt">hydrothermal</span> deposits from geochemically different <span class="hlt">vent</span> fields along the Mid-Atlantic Ridge</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Flores, Gilberto E.; Campbell, James H.; Kirshtein, Julie D.; Meneghin, Jennifer; Podar, Mircea; Steinberg, Joshua I.; Seewald, Jeffrey S.; Tivey, Margaret Kingston; Voytek, Mary A.; Yang, Zamin K.; Reysenbach, Anna-Louise</p> <p>2011-01-01</p> <p>To evaluate the effects of local fluid geochemistry on microbial communities associated with active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> deposits, we examined the archaeal and bacterial communities of 12 samples collected from two very different <span class="hlt">vent</span> fields: the basalt-hosted Lucky Strike (37°17'N, 32°16.3'W, depth 1600-1750m) and the ultramafic-hosted Rainbow (36°13'N, 33°54.1'W, depth 2270-2330m) <span class="hlt">vent</span> fields along the Mid-Atlantic Ridge (MAR). Using multiplexed barcoded pyrosequencing of the variable region 4 (V4) of the 16S rRNA genes, we show statistically significant differences between the archaeal and bacterial communities associated with the different <span class="hlt">vent</span> fields. Quantitative polymerase chain reaction (qPCR) assays of the functional gene diagnostic for methanogenesis (mcrA), as well as geochemical modelling to predict pore fluid chemistries within the deposits, support the pyrosequencing observations. Collectively, these results show that the less reduced, hydrogen-poor fluids at Lucky Strike limit colonization by strict anaerobes such as methanogens, and allow for hyperthermophilic microaerophiles, like Aeropyrum. In contrast, the hydrogen-rich reducing <span class="hlt">vent</span> fluids at the ultramafic-influenced Rainbow <span class="hlt">vent</span> field support the prevalence of methanogens and other hydrogen-oxidizing thermophiles at this <span class="hlt">site</span>. These results demonstrate that biogeographical patterns of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> microorganisms are shaped in part by large scale geological and geochemical processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988DSRA...35.1793L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988DSRA...35.1793L"><span id="translatedtitle">A comparison of bivalve ( Calyptogena magnifica) growth at two deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the eastern Pacific</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lutz, Richard A.; Fritz, Lowell W.; Cerrato, Robert M.</p> <p>1988-10-01</p> <p>Analyses of specimens of a common deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> bivalve, Calyptogena magnifica, from two <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> in the eastern Pacific, have been utilized to develop a mathematical model of the growth of this species based on accurate measurements of: (1) in situ rates of dissolution of the aragonitic outer granular shell layer; and (2) the thickness of the outer shell layer remaining at any given point in time at various distances from the umbo. The model permits the variances of each independently measured variable to be combined into a final confidence limit on age at a given size, making possible statistical comparisons of the calculated parameters of the von Bertalanffy growth equation. This model, in turn, provides a powerful tool for quantifying temporal and spatial variability in rates of biological processes both within and between deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> communities. Ontogenetic growth curves for C. magnifica specimens at both <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> suggest that growth rates of this species are several orders of magnitude greater than those reported for the one bivalve ( Tindaria callistiformis) analysed to date from a deep-sea, non-<span class="hlt">vent</span> habitat. These data provide additional evidence that biological processes at submarine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> along the mid-oceanic ridge system proceed at rates that are extremely rapid for a deep-sea environment and are comparable with those from some shallow water temperate environments. Rates of shell dissolution decreased markedly with increasing distance from <span class="hlt">vent</span> fluids. In a 20 cm distance spanning 10 cm into a bivalve assemblage atop an active <span class="hlt">vent</span> at Rose Garden (Galapagos Rift) to 10 cm outside the assemblage, dissolution rates of the outer granular layer of C. magnifica declined 100-fold (from 355.4 to 3.5 ?m y -1, respectively) in in situ exposures of approximately 210 days. At distances ranging from 1 to 6 m away from active <span class="hlt">vent</span> <span class="hlt">sites</span>, no measurable thickness (<1 ?m) of C. magnifica shells had dissolved. The latter dissolution rates are far below estimates reported in the literature for shells of this species exposed in situ at comparable depths in the eastern Pacific and these results have profound implications for estimating 'residence' times of empty shell valves at inactive <span class="hlt">vent</span> <span class="hlt">sites</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3703533','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3703533"><span id="translatedtitle">Phylogenetic diversity and functional gene patterns of sulfur-oxidizing subseafloor Epsilonproteobacteria in diffuse <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Akerman, Nancy H.; Butterfield, David A.; Huber, Julie A.</p> <p>2013-01-01</p> <p>Microorganisms throughout the dark ocean use reduced sulfur compounds for chemolithoautotrophy. In many deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, sulfide oxidation is quantitatively the most important chemical energy source for microbial metabolism both at and beneath the seafloor. In this study, the presence and activity of <span class="hlt">vent</span> endemic Epsilonproteobacteria was examined in six low-temperature diffuse <span class="hlt">vents</span> over a range of geochemical gradients from Axial Seamount, a deep-sea volcano in the Northeast Pacific. PCR primers were developed and applied to target the sulfur oxidation soxB gene of Epsilonproteobacteria. soxB genes belonging to the genera Sulfurimonas and Sulfurovum are both present and expressed at most diffuse <span class="hlt">vent</span> <span class="hlt">sites</span>, but not in background seawater. Although Sulfurovum-like soxB genes were detected in all fluid samples, the RNA profiles were nearly identical among the <span class="hlt">vents</span> and suggest that Sulfurimonas-like species are the primary Epsilonproteobacteria responsible for actively oxidizing sulfur via the Sox pathway at each <span class="hlt">vent</span>. Community patterns of subseafloor Epsilonproteobacteria 16S rRNA genes were best matched to methane concentrations in <span class="hlt">vent</span> fluids, as well as individual <span class="hlt">vent</span> locations, indicating that both geochemistry and geographical isolation play a role in structuring subseafloor microbial populations. The data show that in the subseafloor at Axial Seamount, Epsilonproteobacteria are expressing the soxB gene and that microbial patterns in community distribution are linked to both <span class="hlt">vent</span> location and chemistry. PMID:23847608</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23231657','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23231657"><span id="translatedtitle">Comparison of intact polar lipid with microbial community composition of <span class="hlt">vent</span> deposits of the Rainbow and Lucky Strike <span class="hlt">hydrothermal</span> fields.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gibson, R A; van der Meer, M T J; Hopmans, E C; Reysenbach, A-L; Schouten, S; Sinninghe Damsté, J S</p> <p>2013-01-01</p> <p>The intact polar lipid (IPL) composition of twelve <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> deposits from the Rainbow (RHF) and Lucky Strike <span class="hlt">hydrothermal</span> fields (LSHF) has been investigated in order to assess its utility as a proxy for microbial community composition associated with deep-sea <span class="hlt">hydrothermal</span> locations. Gene-based culture-independent surveys of the microbial populations of the same <span class="hlt">vent</span> deposits have shown that microbial populations are different in the two locations and appear to be controlled by the geochemical and geological processes that drive <span class="hlt">hydrothermal</span> circulation. Large differences in the IPL composition between these two <span class="hlt">sites</span> are evident. In the ultramafic-hosted RHF, mainly archaeal-IPLs were identified, including those known to be produced by hyperthermophilic Euryarchaeota. More specifically, polyglycosyl derivatives of archaeol and macrocyclic archaeol indicate the presence of hyperthermophilic methanogenic archaea in the <span class="hlt">vent</span> deposits, which are related to members of the Methanocaldococcaceae or Methanococcaceae. In contrast, bacterial IPLs dominate IPL distributions from LSHF, suggesting that bacteria are more predominant at LSHF than at RHF. Bacterial Diacyl glycerol (DAG) IPLs containing phosphocholine, phosphoethanolamine or phosphoglycerol head groups were identified at both <span class="hlt">vent</span> fields. In some <span class="hlt">vent</span> deposits from LSHF ornithine lipids and IPLs containing phosphoaminopentanetetrol head groups were also observed. By comparison with previously characterized bacterial communities at the <span class="hlt">sites</span>, it is likely the DAG-IPLs observed derive from Epsilon- and Gammaproteobacteria. Variation in the relative amounts of archaeal versus bacterial IPLs appears to indicate differences in the microbial community between <span class="hlt">vent</span> <span class="hlt">sites</span>. Overall, IPL distributions appear to be consistent with gene-based surveys. PMID:23231657</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeCoA.173...64J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeCoA.173...64J"><span id="translatedtitle">Precipitation and growth of barite within <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> deposits from the Endeavour Segment, Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jamieson, John William; Hannington, Mark D.; Tivey, Margaret K.; Hansteen, Thor; Williamson, Nicole M.-B.; Stewart, Margaret; Fietzke, Jan; Butterfield, David; Frische, Matthias; Allen, Leigh; Cousens, Brian; Langer, Julia</p> <p>2016-01-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> deposits form on the seafloor as a result of cooling and mixing of hot <span class="hlt">hydrothermal</span> fluids with cold seawater. Amongst the major sulfide and sulfate minerals that are preserved at <span class="hlt">vent</span> <span class="hlt">sites</span>, barite (BaSO4) is unique because it requires the direct mixing of Ba-rich <span class="hlt">hydrothermal</span> fluid with sulfate-rich seawater in order for precipitation to occur. Because of its extremely low solubility, barite crystals preserve geochemical fingerprints associated with conditions of formation. Here, we present data from petrographic and geochemical analyses of <span class="hlt">hydrothermal</span> barite from the Endeavour Segment of the Juan de Fuca Ridge, northeast Pacific Ocean, in order to determine the physical and chemical conditions under which barite precipitates within seafloor <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems. Petrographic analyses of 22 barite-rich samples show a range of barite crystal morphologies: dendritic and acicular barite forms near the exterior <span class="hlt">vent</span> walls, whereas larger bladed and tabular crystals occur within the interior of chimneys. A two component mixing model based on Sr concentrations and 87Sr/86Sr of both seawater and <span class="hlt">hydrothermal</span> fluid, combined with 87Sr/86Sr data from whole rock and laser-ablation ICP-MS analyses of barite crystals indicate that barite precipitates from mixtures containing as low as 17% and as high as 88% <span class="hlt">hydrothermal</span> fluid component, relative to seawater. Geochemical modelling of the relationship between aqueous species concentrations and degree of fluid mixing indicates that Ba2+ availability is the dominant control on mineral saturation. Observations combined with model results support that dendritic barite forms from fluids of less than 40% <span class="hlt">hydrothermal</span> component and with a saturation index greater than ?0.6, whereas more euhedral crystals form at lower levels of supersaturation associated with greater contributions of <span class="hlt">hydrothermal</span> fluid. Fluid inclusions within barite indicate formation temperatures of between ?120 °C and 240 °C during barite crystallization. The comparison of fluid inclusion formation temperatures to modelled mixing temperatures indicates that conductive cooling of the <span class="hlt">vent</span> fluid accounts for 60-120 °C reduction in fluid temperature. Strontium zonation within individual barite crystals records fluctuations in the amount of conductive cooling within chimney walls that may result from cyclical oscillations in <span class="hlt">hydrothermal</span> fluid flux. Barite chemistry and morphology can be used as a reliable indicator for past conditions of mineralization within both extinct seafloor <span class="hlt">hydrothermal</span> deposits and ancient land-based volcanogenic massive sulfide deposits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMOS21B0448W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMOS21B0448W"><span id="translatedtitle">Continuous Monitoring of <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Chemistry: A Window to Subseafloor Processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wheat, C. G.; Jannasch, H.; Plant, J.; Butterfield, D.; Lupton, J.; Moyer, C.; Tivey, M.; Embley, R.</p> <p>2001-12-01</p> <p><span class="hlt">Hydrothermal</span> circulation through mid-ocean ridges are driven by episodic intrusions of basaltic magma. These intrusions change paths for fluid circulation on scales of hours to more than decades. These changes in plumbing ultimately affect the chemical and thermal composition of <span class="hlt">hydrothermal</span> fluids. Similarly, changes in effluent chemistry are expected as a result of periodic variability in oceanic conditions resulting in differing degrees of dilution with seawater and the potential for further water-rock reactions at low temperatures. Thus, changes in effluent chemistry provide a unique window to processes affecting seawater circulation through oceanic crust. Continuous water samplers (OsmoSamplers) with self contained temperature recorders provide a reliable tool to monitor the concentration of dissolved gases and the major, minor, and trace elements in and temperature of <span class="hlt">hydrothermal</span> effluent. Samplers have been deployed for several days to more than 3 years in several <span class="hlt">vents</span> at the Main Endeavour Field (MEF) and Axial Seamount. High resolution samplers deployed for 5-10 days at both <span class="hlt">sites</span> provide hourly aliquots from which we document the effects of changes in bottom currents (3-day, daily, and tidal) on the extent of subsurface and near surface mixing of <span class="hlt">hydrothermal</span> and bottom seawater. Longer deployments (1 year) document a variety of changes. At Axial Seamount we observed the gradual and sudden extinction of <span class="hlt">venting</span> and the gradual decrease in subsurface mixing with unaltered bottom seawater. These results are being synthesized with thermal and hydroacoustic data to match chemical changes with physical processes. In contrast, samplers deployed at MEF for two months display a remarkable consistency in composition. Coupled with flow meters, large volume fluid samplers, and seismometers, OsmoSamplers are valuable tools in discerning processes that control <span class="hlt">hydrothermal</span> circulation in this dynamic environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.V72A1297U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.V72A1297U"><span id="translatedtitle">Measurement of in situ Methane Oxidation Rate in <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Area, Suiyo Seamount in the Izu-Bonin Arc</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Utsumi, M.; Tsunogai, U.; Ishibashi, J.</p> <p>2002-12-01</p> <p>Methane is one of the important carbon sources for the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystem. Extensive studies about dissolved methane concentration and methane carbon isotope composition at <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> area have been investigated, much remains to be learned about methane production and oxidation by microorganisms at the ecosystem. The quantitative estimation of the organic carbon supply to the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystem with methane oxidation by the microorganisms is an important study in order to grasp carbon flow of the ecosystem. In the present study, we measured in situ oxidation rate of dissolved methane at <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> area in the Suiyo Seamount, Izu-Bonin (Ogasawara) Arc. The oxidation measuring equipment which was combined Niskin water sampler with Time-series water sampler having 12 acrylic cylinders was attached to the Japanese manned submersible SHINKAI 2000. At the sea floor, Niskin sampler was hold up just above the low temperature <span class="hlt">vent</span> and sea water in the sampler was replaced in the <span class="hlt">hydrothermal</span> fluid. Then the Niskin sampler closed just before starting time-series sampling and incubation experiment started on <span class="hlt">site</span>. <span class="hlt">Hydrothermal</span> fluid in Niskin sampler was sampled in the 30 min or 1 hour interval by Time-series water sampler and methane oxidation was stopped immediately by mercuric chloride solution added in each cylinder previously. Time-series samples were immediately transferred to the 30-ml glass bottles on board. Bottles were slowly overflowed with sample water and sealed with no headspace. After sealing, the samples were stored in freezer until methane concentration analysis at the laboratory. The dissolved methane concentration was measured with an automatic system consisting of a purge and trap apparatus and a gas chromatograph with a flame ionization detector. The in situ methane oxidation rate at the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> area was 0.016/hr, and methane consumption rate, which is obtained from multiplying the methane oxidation rate by the methane concentration, was 13.6 nM CH4/hr. It suggests that dissolved methane oxidation by microorganisms should be an important organic carbon source for the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystem at the Suiyo Seamount.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010GeoJI.180..883V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010GeoJI.180..883V"><span id="translatedtitle">Application of acoustic noise and self-potential localization techniques to a buried <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> (Waimangu Old Geyser <span class="hlt">site</span>, New Zealand)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vandemeulebrouck, J.; Roux, P.; Gouédard, P.; Legaz, A.; Revil, A.; Hurst, A. W.; Bolève, A.; Jardani, A.</p> <p>2010-02-01</p> <p>A seismo-acoustic and self-potential survey has been performed in the <span class="hlt">hydrothermal</span> area of the old Waimangu Geyser (New Zealand), which was violently erupting a century ago. Nowadays, no surface activity is visible there. We set-up an array of 16 geophones and recorded a high and steady acoustic ambient noise. We applied the matched field processing (MFP) approach to the acoustic data to locate the sources responsible for the ambient noise. The white noise constraint processor reveals the presence of a unique and well-focused acoustic source at a depth of 1.5 m below the seismic array. For this very shallow source, the application of MFP enabled the determination of both the source location and the dispersion curve of seismic velocity. The study was completed by self-potential (SP) measurements on several profiles around the acoustic noise source, which displayed a large positive anomaly above it. The results of the SP inversion gave an electric streaming current density source very close to the acoustic one. Both sources likely belong to a shallow <span class="hlt">hydrothermal</span> structure interpreted as a small convective cell of boiling water beneath an impermeable layer. The joint application of these methods is a promising technique to recognize <span class="hlt">hydrothermal</span> structures and to study their dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMOS22A..08B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMOS22A..08B"><span id="translatedtitle">GALREX 2011: Extensive <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> discovered along the eastern Galápagos Rift</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baker, E. T.; Walker, S. L.; White, S. M.; Embley, R. W.; Resing, J. A.; Lobecker, M.</p> <p>2011-12-01</p> <p>Leg 1 of the Galápagos Rift Expedition (GALREX) on the NOAA Ship Okeanos Explorer, July 2011, conducted a 400-km-long continuous CTD transect to map active <span class="hlt">hydrothermal</span> areas between 89.33° and 87.75°W. Light backscattering (?NTU) and oxidation-reduction potential (ORP) sensors measured the relative concentration of suspended particles and reduced <span class="hlt">hydrothermal</span> chemicals, respectively. GALREX was designed to complement a similar survey in 2005/2006 that surveyed the central Galápagos Rift from 94.9° to 89.6°W. That survey found only two active high-temperature <span class="hlt">vent</span> fields, plus robust plume evidence for at least six smaller fields. The spatial density of <span class="hlt">hydrothermal</span> plumes (ph) along the rift was only 0.11 (based on ?NTU anomalies), significantly less than expected for intermediate-rate (50-60 mm/yr) spreading but similar to other hotspot-affected ridges (e.g., near the Iceland, Ascension, and St. Paul-Amsterdam hotspots). This low ph value was hypothesized to be an expression of (1) reduced <span class="hlt">hydrothermal</span> discharge on ridge sections with hotspot-thickened crust, (2), widespread low-temperature discharge undetectable by large-scale surveys, or (3) episodic <span class="hlt">venting</span>. GALREX found a distinctly different <span class="hlt">hydrothermal</span> environment on the eastern third of the rift. Overall, ph = 0.19, about twice that of the central Galápagos Rift. Strong <span class="hlt">venting</span> was concentrated in two areas. Most remarkable was a 50-km-long section (88.56°-88.09°W) where continuous plumes with high (>0.2) ?NTU values rose as high as 250 m above the seafloor. This area is low amplitude valley and ridge topography, centered on a relatively recent lava flow at 88.33°W. The second area included the historical <span class="hlt">vent</span> fields Rose Garden and Rosebud, and ranged from 86.25° to 85.87°W. In this area ?NTU was lower (~0.1) and plumes were patchy. ORP anomalies occasionally occurred in the absence of ?NTU anomalies, suggesting low-temperature, particle-poor <span class="hlt">vent</span> sources. No anomalies were detected over the Rose Garden/Rosebud <span class="hlt">sites</span>. The entire GALREX survey detected ~20 discrete ORP anomalies, with along-axis separations ranging from 2 to 110 km (median=14 km). Because ORP anomalies are very short lived, and thus do not advect far from their seafloor source, at least ~20 distinct <span class="hlt">vent</span> "fields" must be active, a higher spatial frequency than found along the central Galápagos Rift. The eastern rift section is also notable for supporting two areas of extensive <span class="hlt">venting</span>, each >40 km along axis, and each paved by apparently young (~10 yr) lavas. Each of these areas is ~3x longer than the longest <span class="hlt">hydrothermal</span> area on the central rift section.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.B13B0475S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.B13B0475S"><span id="translatedtitle">Bacterial and Archaeal Community Dynamics at CO2-RICH Shallow-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> (panarea, Italy)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schubotz, F.; Huang, C.; Meyerdierks, A.; Amend, J.; Price, R. E.; Amann, R.; Hinrichs, K.; Summons, R. E.</p> <p>2013-12-01</p> <p>Shallow marine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are highly dynamic systems with unique habitats that can support both chemosynthetic and photosynthetic communities at steep temperature and geochemical gradients. Here, we present a combined organic geochemical and microbiological approach to describe the microbial community composition and their metabolism at the CO2-rich shallow <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> off Panarea Island, in Sicily. We investigated two contrasting <span class="hlt">hydrothermal</span> environments: Hot Lake, a depression filled with <span class="hlt">hydrothermal</span> fluids diffusing gradually out of the seafloor, with temperatures ranging from 40 to 70°C, and Blackpoint, a <span class="hlt">site</span> with vigorous <span class="hlt">venting</span> of <span class="hlt">hydrothermal</span> gasses and fluids with temperatures as high as 135°C. At Hot Lake, Bacteria dominate the microbial community composition in the sediments. 16S rRNA clone libraries revealed Bacteriodetes-, Epsilonproteobacteria- and Deltaproteobacteria-related sequences as the most abundant members. Bacterial intact polar membrane lipids (IPLs) were dominated by the non-phosphorous containing ornithine lipids throughout all depths, indicating an important role of this aminolipid at elevated temperatures and/or low pH. At Hot Lake, archaeal IPLs were comprised mainly of glycosidic tetraethers and increased up to 20% of total IPLs with increasing temperature and depth. At the same <span class="hlt">site</span>, archaeal 16S rRNA clone libraries were mainly comprised of Euryarchaea-affiliated sequences; crenarchaeotal sequences were only found in deeper sediment layers with temperatures of ca. 70°C. In contrast to Hot Lake, Archaea dominated sediments at the much hotter <span class="hlt">site</span> at Blackpoint. Here, novel methylated H-shaped archaeal tetraethers, with multiple sugars as head groups, were the most abundant membrane lipids. Reports on these lipids in cultures are very limited, but their abundant occurrence at elevated temperatures suggests an important role in membrane homeostastis in thermophilic Archaea. Stable carbon isotope values of -35‰ to -10‰ for bacterial fatty acids and archaeal ether lipids indicate that microbial communities at both Hot Lake and Blackpoint are primarily autotrophic (?13CTOC ~ -20‰, ?13CDIC ~ +3‰). We will discuss potential carbon fixation pathways in light of known isotopic fractionations for lipids, and accompanying metagenome investigations, which suggests the reductive tricaboxylic acid cycle as important carbon fixation pathway at Hot Lake.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23647923','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23647923"><span id="translatedtitle">Linking geology, fluid chemistry, and microbial activity of basalt- and ultramafic-hosted deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Perner, M; Hansen, M; Seifert, R; Strauss, H; Koschinsky, A; Petersen, S</p> <p>2013-07-01</p> <p><span class="hlt">Hydrothermal</span> fluids passing through basaltic rocks along mid-ocean ridges are known to be enriched in sulfide, while those circulating through ultramafic mantle rocks are typically elevated in hydrogen. Therefore, it has been estimated that the maximum energy in basalt-hosted systems is available through sulfide oxidation and in ultramafic-hosted systems through hydrogen oxidation. Furthermore, thermodynamic models suggest that the greatest biomass potential arises from sulfide oxidation in basalt-hosted and from hydrogen oxidation in ultramafic-hosted systems. We tested these predictions by measuring biological sulfide and hydrogen removal and subsequent autotrophic CO2 fixation in chemically distinct <span class="hlt">hydrothermal</span> fluids from basalt-hosted and ultramafic-hosted <span class="hlt">vents</span>. We found a large potential of microbial hydrogen oxidation in naturally hydrogen-rich (ultramafic-hosted) but also in naturally hydrogen-poor (basalt-hosted) <span class="hlt">hydrothermal</span> fluids. Moreover, hydrogen oxidation-based primary production proved to be highly attractive under our incubation conditions regardless whether <span class="hlt">hydrothermal</span> fluids from ultramafic-hosted or basalt-hosted <span class="hlt">sites</span> were used. <span class="hlt">Site</span>-specific hydrogen and sulfide availability alone did not appear to determine whether hydrogen or sulfide oxidation provides the energy for primary production by the free-living microbes in the tested <span class="hlt">hydrothermal</span> fluids. This suggests that more complex features (e.g., a combination of oxygen, temperature, biological interactions) may play a role for determining which energy source is preferably used in chemically distinct <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> biotopes. PMID:23647923</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3676328','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3676328"><span id="translatedtitle">Spatial Differences in East Scotia Ridge <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Food Webs: Influences of Chemistry, Microbiology and Predation on Trophodynamics</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Reid, William D. K.; Sweeting, Christopher J.; Wigham, Ben D.; Zwirglmaier, Katrin; Hawkes, Jeffrey A.; McGill, Rona A. R.; Linse, Katrin; Polunin, Nicholas V. C.</p> <p>2013-01-01</p> <p>The <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the East Scotia Ridge are the first to be explored in the Antarctic and are dominated by large peltospiroid gastropods, stalked barnacles (Vulcanolepas sp.) and anomuran crabs (Kiwa sp.) but their food webs are unknown. <span class="hlt">Vent</span> fluid and macroconsumer samples were collected at three <span class="hlt">vent</span> <span class="hlt">sites</span> (E2, E9N and E9S) at distances of tens of metres to hundreds of kilometres apart with contrasting <span class="hlt">vent</span> fluid chemistries to describe trophic interactions and identify potential carbon fixation pathways using stable isotopes. ?13C of dissolved inorganic carbon from <span class="hlt">vent</span> fluids ranged from ?4.6‰ to 0.8‰ at E2 and from ?4.4‰ to 1.5‰ at E9. The lowest macroconsumer ?13C was observed in peltospiroid gastropods (?30.0‰ to ?31.1‰) and indicated carbon fixation via the Calvin-Benson-Bassham (CBB) cycle by endosymbiotic gamma-Proteobacteria. Highest ?13C occurred in Kiwa sp. (?19.0‰ to ?10.5‰), similar to that of the epibionts sampled from their ventral setae. Kiwa sp. ?13C differed among <span class="hlt">sites</span>, which were attributed to spatial differences in the epibiont community and the relative contribution of carbon fixed via the reductive tricarboxylic acid (rTCA) and CBB cycles assimilated by Kiwa sp. <span class="hlt">Site</span> differences in carbon fixation pathways were traced into higher trophic levels e.g. a stichasterid asteroid that predates on Kiwa sp. Sponges and anemones at the periphery of E2 assimilated a proportion of epipelagic photosynthetic primary production but this was not observed at E9N. Differences in the ?13C and ?34S values of <span class="hlt">vent</span> macroconsumers between E2 and E9 <span class="hlt">sites</span> suggest the relative contributions of photosynthetic and chemoautotrophic carbon fixation (rTCA v CBB) entering the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> food webs vary between the <span class="hlt">sites</span>. PMID:23762393</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.B43G0496O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.B43G0496O"><span id="translatedtitle">Microbial Primary Productivity in <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Chimneys at Middle Valley, Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Olins, H. C.; Rogers, D.; Frank, K. L.; Girguis, P. R.; Vidoudez, C.</p> <p>2012-12-01</p> <p>Chemosynthetic primary productivity supports <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystems, but the extent of that productivity has not been well measured. To examine the role that environmental temperature plays in controlling carbon fixation rates, and to assess the degree to which microbial community composition, in situ geochemistry, and mineralogy influence carbon fixation, we conducted a series of shipboard incubations across a range of temperatures (4, 25, 50 and 90°C) and at environmentally relevant geochemical conditions using material recovered from three <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimneys in the Middle Valley <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field (Juan de Fuca Ridge). Net rates of carbon fixation (CFX) were greatest at lower temperatures, and were similar among structures. Rates did not correlate with the mineralogy or the geochemical composition of the high temperature fluids at each chimney. No obvious patterns of association were observed between carbon fixation rates and microbial community composition. Abundance of selected functional genes related to different carbon fixation pathway exhibited striking differences among the three study <span class="hlt">sites</span>, but did not correlate with rates. Natural carbon isotope ratios implicate the Calvin Benson Bassham Cycle as the dominant mechanism of primary production in these systems, despite the abundance of genes related to other pathways (and presumably some degree of activity). Together these data reveal that primary productivity by endolithic communities does not exhibit much variation among these chimneys, and further reveal that microbial activity cannot easily be related to mineralogical and geochemical assessments that are made at a coarser scale. Indeed, the relationships between carbon fixation rates and community composition/functional gene abundance were also likely obfuscated by differences in scale at which these measurements were made. Regardless, these data reveal the degree to which endolithic, anaerobic carbon fixation contributes to regional primary production, and via modeling reveal the role that this process plays in deep-sea and global carbon cycling.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://marine.rutgers.edu/ebme/papers/Andrianasolo_et_al_J_Nat_Prod_2009.pdf','EPRINT'); return false;" href="http://marine.rutgers.edu/ebme/papers/Andrianasolo_et_al_J_Nat_Prod_2009.pdf"><span id="translatedtitle">Ammonificins A and B, Hydroxyethylamine Chroman Derivatives from a Cultured Marine <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Bacterium, ThermoWibrio ammonificans</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Falkowski, Paul G.</p> <p></p> <p>), were isolated from the marine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> bacterium ThermoVibrio ammonificans. The molecular report of secondary metabolites from the marine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> bacterium T. ammonificans. The oceansAmmonificins A and B, Hydroxyethylamine Chroman Derivatives from a Cultured Marine <span class="hlt">Hydrothermal</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.gps.caltech.edu/users/jkirschvink/pdfs/SuzukiGastropodGreigite.pdf','EPRINT'); return false;" href="http://www.gps.caltech.edu/users/jkirschvink/pdfs/SuzukiGastropodGreigite.pdf"><span id="translatedtitle">Sclerite formation in the <span class="hlt">hydrothermal-vent</span> bscaly-footQ gastropod--possible control of iron sulfide</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Kirschvink, Joseph L.</p> <p></p> <p>Sclerite formation in the <span class="hlt">hydrothermal-vent</span> bscaly-footQ gastropod--possible control of iron; biomineralization; <span class="hlt">hydrothermal-vent</span> gastropod; sclerite 1. Introduction The bscaly-footQ gastropod (Fig. 1), so 10 January 2006 Editor: E. Boyle Abstract A gastropod from a deep-sea <span class="hlt">hydrothermal</span> field</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5108926','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5108926"><span id="translatedtitle">Relationships between lava types, seafloor morphology, and the occurrence of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> in the ASHES <span class="hlt">vent</span> field of Axial Volcano. [Axial Seamount <span class="hlt">Hydrothermal</span> Emission Study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hammond, S.R. )</p> <p>1990-08-10</p> <p>Deep-towed and submersible photographic surveys within the caldera of Axial Volcano have been integrated with high-resolution bathmetry to produce a geological map of the most active <span class="hlt">vent</span> field in the caldera. Locations for over 2,000 photographs in and near the <span class="hlt">vent</span> field were determined using a seafloor transponder network. Then each photograph was described utilizing a classification system which provides detailed information concerning lava type, <span class="hlt">hydrothermal</span> activity, sediment cover, geological structure, and biology. Resulting data were entered into a digital data base, and computer-generated maps were created that portray spatial relationships between selected geological variables. In general, the entire ASHES field is characterized by pervasive low-temperature <span class="hlt">venting</span>. The most vigorous <span class="hlt">venting</span> is concentrated in an approximately 80 m {times} 80 m area where there are several high-temperature <span class="hlt">vents</span> including some which are producing high-temperature vapor-phase fluids derived from a boiling <span class="hlt">hydrothermal</span> system. Lava types within the ASHES <span class="hlt">vent</span> field are grouped into three distinct morphologies: (1) smooth (flat-surfaced, ropy, and whorled) sheet flows, (2) lobate flows, and (3) jumbled-sheet flows. The most intense <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> is concentrated in the smooth sheet flows and the lobate flows. The location of the ASHES field is mainly attributable to faulting which defines the southwest caldera wall, but the concentration of intense <span class="hlt">venting</span> appears to be related also to the spatial distribution of lava types in the <span class="hlt">vent</span> field and their contrasting permeabilities. Other structural trends of faults and fissures within the field also influence the location of individual events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.V32A0959O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.V32A0959O"><span id="translatedtitle">Study of <span class="hlt">Hydrothermal</span> Particulate Matter from a Shallow <span class="hlt">Venting</span> System, offshore Nayarit, Mexico</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ortega-Osorio, A.; Prol-Ledesma, R. M.; Reyes, A. G.; Rubio-Ramos, M. A.; Torres-Vera, M. A.</p> <p>2001-12-01</p> <p>A shallow (30 ft) <span class="hlt">hydrothermal</span> <span class="hlt">site</span> named ``Cora'' (after the indigenous people thereby) was surveyed and sampled throughout direct observation with SCUBA diving during November 25 to December 4, 2000. A total of 10 dives were conducted in order to obtain representative samples from an 85oC fluid source of approximately 10 cm in diameter. Inherent difficulties to the sampling, such as poor visibility and strong bottom currents were overcome and samples of <span class="hlt">hydrothermal</span> fluid, gas, rocks, and particulate matter were collected directly from the <span class="hlt">vent</span>. Water samples and <span class="hlt">hydrothermal</span> fluid were taken with a homemade 1 l cylindrical bottles of two lines by flushing in from the bottom for about ten minutes until total displacement of the seawater; similar procedure was carried out for gas samples. Particulate matter was collected with 0.4mm polycarbonate membrane filters and preserved in a desiccators at a fridge temperature until analysis onshore. Preliminary description of the rock samples suggest that pyritization is the main mineralisation process. Filters containing <span class="hlt">hydrothermal</span> particulate matter were surveyed under the scanning electron microscope in order to identify the nature (inorganic and organic), as well as the chemistry of the particles. SEM examination revealed the presence of particles of different kind that suggests high degree of mixing and re-suspension: Planctonic organisms and organic matter appeared to be abundant; 25 micron particles of different carbonate faces and inorganic particles of silicates were also recognized. Distinctive euhedral colloidal grains were identified as the resulting process of precipitation from the solution. Microanalysis of iron and sulfur content of 10 micron particles indicate a very likely sulphide mineral face (greigite); 8 micron cinnabar particles are consistent with the mineralization conditions, observed as well in the inner walls of the <span class="hlt">vent</span>. Analyses of dissolved and particulate trace metals are still ongoing at labs in New Zealand and Mexico and will be incorporated in a near future.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26431911','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26431911"><span id="translatedtitle">Effect of sulfide, osmotic, and thermal stresses on taurine transporter mRNA levels in the gills of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>-specific mussel Bathymodiolus septemdierum.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nakamura-Kusakabe, Ikumi; Nagasaki, Toshihiro; Kinjo, Azusa; Sassa, Mieko; Koito, Tomoko; Okamura, Kei; Yamagami, Shosei; Yamanaka, Toshiro; Tsuchida, Shinji; Inoue, Koji</p> <p>2016-01-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> environmental conditions are characterized by high sulfide concentrations, fluctuating osmolality, and irregular temperature elevations caused by <span class="hlt">vent</span> effluents. These parameters represent potential stressors for organisms that inhabit the area around <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Here, we aimed to obtain a better understanding of the adaptation mechanisms of marine species to <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments. Specifically, we examined the effect of sulfide, osmolality, and thermal stress on the expression of taurine transporter (TAUT) mRNA in the gill of the deep-sea mussel Bathymodiolus septemdierum, which is a dominant species around <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span>. We analyzed TAUT mRNA levels by quantitative real-time polymerase chain reaction (PCR) in the gill of mussels exposed to sulfide (0.1 or 1mg/L Na2S·9H2O), hyper- (115% seawater) and hypo- (97.5%, 95.5%, and 85% seawater) osmotic conditions, and thermal stresses (12°C and 20°C) for 24 and 48h. The results showed that mussels exposed to relatively low levels of sulfide (0.1mg/L) and moderate heat stress (12°C) exhibited higher TAUT mRNA levels than the control. Although hyper- and hypo-osmotic stress did not significantly change TAUT mRNA levels, slight induction was observed in mussels exposed to low osmolality. Our results indicate that TAUT is involved in the coping mechanism of mussels to various <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> stresses. PMID:26431911</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3659317','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3659317"><span id="translatedtitle">The microbiology of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> plumes: ecological and biogeographic linkages to seafloor and water column habitats</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dick, Gregory J.; Anantharaman, Karthik; Baker, Brett J.; Li, Meng; Reed, Daniel C.; Sheik, Cody S.</p> <p>2013-01-01</p> <p><span class="hlt">Hydrothermal</span> plumes are an important yet understudied component of deep-sea <span class="hlt">vent</span> microbial ecosystems. The significance of plume microbial processes can be appreciated from three perspectives: (1) mediation of plume biogeochemistry, (2) dispersal of seafloor <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> microbes between <span class="hlt">vents</span> <span class="hlt">sites</span>, (3) as natural laboratories for understanding the ecology, physiology, and function of microbial groups that are distributed throughout the pelagic deep sea. Plume microbiology has been largely neglected in recent years, especially relative to the extensive research conducted on seafloor and subseafloor systems. Rapidly advancing technologies for investigating microbial communities provide new motivation and opportunities to characterize this important microbial habitat. Here we briefly highlight microbial contributions to plume and broader ocean (bio)geochemistry and review recent work to illustrate the ecological and biogeographic linkages between plumes, seafloor <span class="hlt">vent</span> habitats, and other marine habitats such as oxygen minimum zones (OMZs), cold seeps, and oil spills. 16S rRNA gene surveys and metagenomic/-transcriptomic data from plumes point to dominant microbial populations, genes, and functions that are also operative in OMZs (SUP05, ammonia-oxidizing Archaea, and SAR324 Deltaproteobacteria) and hydrocarbon-rich environments (methanotrophs). Plume microbial communities are distinct from those on the seafloor or in the subsurface but contain some signatures of these habitats, consistent with the notion that plumes are potential vectors for dispersal of microorganisms between seafloor <span class="hlt">vent</span> <span class="hlt">sites</span>. Finally, we put forward three pressing questions for the future of deep-sea <span class="hlt">hydrothermal</span> plume research and consider interactions between <span class="hlt">vents</span> and oceans on global scales. PMID:23720658</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://geoscience.wisc.edu/astrobiology/wp-content/uploads/2015/06/Streit_et_al_2015_Deep_Sea_Res.pdf','EPRINT'); return false;" href="http://geoscience.wisc.edu/astrobiology/wp-content/uploads/2015/06/Streit_et_al_2015_Deep_Sea_Res.pdf"><span id="translatedtitle">Sources of organic carbon for Rimicaris hybisae: Tracing individual fatty acids at two <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields in the Mid-Cayman rise</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Johnson, Clark M.</p> <p></p> <p>Keywords: Chemosynthetic carbon source Photosynthetic carbon source <span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> chemistry Piccard Von Damm Ectosymbionts a b s t r a c t <span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> harbor ecosystems mostly decoupled from organic with ectosymbiotic bacteria, at two <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields in the Mid-Cayman rise that differ in <span class="hlt">vent</span> chemistry</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008DSRI...55.1707L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008DSRI...55.1707L"><span id="translatedtitle">Biotic interactions at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>: Recruitment inhibition by the mussel Bathymodiolus thermophilus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lenihan, H. S.; Mills, S. W.; Mullineaux, L. S.; Peterson, C. H.; Fisher, C. R.; Micheli, F.</p> <p>2008-12-01</p> <p>The structure and dynamics of marine communities are regulated in part by variation in recruitment. As in other ecosystems, recruitment at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> is controlled by the interplay of propagule supply and behavior, gradients in physical-chemical conditions, and biotic interactions during pre- and post-settlement periods. Recent research along the East Pacific Rise indicates that inhibition of recently settled larvae by mobile predators (mainly limpets) influences patterns of recruitment and subsequent community succession. We conducted a manipulative experiment at the same <span class="hlt">sites</span> (˜2510 m water depth) to test whether high-density assemblages of the mussel Bathymodiolus thermophilus also inhibit recruitment. In a preliminary study, recruitment of <span class="hlt">vent</span> invertebrates within the faunal zone dominated by B. thermophilus was strikingly different at two <span class="hlt">sites</span>, East Wall and Worm Hole. East Wall had high densities of mussels but very low total recruitment. In contrast, Worm Hole had few mussels but high recruitment. Using the submersible Alvin, we transplanted a large number of mussels from East Wall to Worm Hole and quantified recruitment on basalt blocks placed in three treatments: (1) naturally high densities of mussels at East Wall; (2) naturally low densities of mussels at Worm Hole; and (3) high densities of transplanted mussels at Worm Hole. After 11 months, a total of 24 taxa had recruited to the basalt blocks. Recruitment was 44-60% lower in the transplanted high-density mussel patch at Worm Hole and the natural high-density patch at East Wall than within the natural low-density patch at Worm Hole. Biotic processes that may have caused the pattern of recruitment observed included predation of larvae via water filtration by mussels, larval avoidance of superior competitors, interference competition, and enhanced predation by species within the mussel-bed community. Our results indicate that biotic interactions affecting recruitment must be understood to explain patterns of invertebrate community organization and dynamics at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25911507','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25911507"><span id="translatedtitle">An abyssal mobilome: viruses, plasmids and vesicles from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lossouarn, Julien; Dupont, Samuel; Gorlas, Aurore; Mercier, Coraline; Bienvenu, Nadege; Marguet, Evelyne; Forterre, Patrick; Geslin, Claire</p> <p>2015-12-01</p> <p>Mobile genetic elements (MGEs) such as viruses, plasmids, vesicles, gene transfer agents (GTAs), transposons and transpovirions, which collectively represent the mobilome, interact with cellular organisms from all three domains of life, including those thriving in the most extreme environments. While efforts have been made to better understand deep-sea <span class="hlt">vent</span> microbial ecology, our knowledge of the mobilome associated with prokaryotes inhabiting deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> remains limited. Here we focus on the abyssal mobilome by reviewing accumulating data on viruses, plasmids and vesicles associated with thermophilic and hyperthermophilic Bacteria and Archaea present in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. PMID:25911507</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70014522','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70014522"><span id="translatedtitle">Submarine fissure eruptions and <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the southern Juan de Fuca Ridge: preliminary observations from the submersible Alvin.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Normark, W.R.</p> <p>1986-01-01</p> <p>The submersible Alvin was used to investigate 3 active <span class="hlt">hydrothermal</span> discharge <span class="hlt">sites</span> along the S Juan de Fuca Ridge in September 1984. The <span class="hlt">hydrothermal</span> zones occur within a 10-30m-deep, 30-50m-wide cleft marking the center of the axial valley. This cleft is the eruptive locus for the axial valley. The <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> coincide with the main eruptive <span class="hlt">vents</span> along the cleft. Each <span class="hlt">hydrothermal</span> zone has multiple discharge <span class="hlt">sites</span> extending as much as 500m along the cleft. Sulfide deposits occur as clusters (15-100m2 area) of small chimneys (= or <2m high) and as individual and clustered fields of large, branched chimneys (= or <10m high). Recovered sulfide samples are predominantly the tops of chimneys and spires and typically contain more than 80% sphalerite and wurtzite with minor pyrrhotite, pyrite, marcasite, isocubanite, chalcopyrite, anhydrite, anhydrite, and amorphous silica. The associated <span class="hlt">hydrothermal</span> fluids have the highest chlorinity of any reported to date.-Authors</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS53C1057B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS53C1057B"><span id="translatedtitle">Abundant <span class="hlt">Hydrothermal</span> <span class="hlt">Venting</span> in the Southern Ocean Near 62°S/159°E on the Australian-Antarctic Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baker, E. T.; Hahm, D.; Rhee, T. S.; Park, S. H.; Lupton, J. E.; Walker, S. L.; Choi, H.</p> <p>2014-12-01</p> <p>Circum-Antarctic Ridges (CARs) comprise almost one-third of the global Mid-Ocean Ridge, yet remain terra incognita for <span class="hlt">hydrothermal</span> activity and chemosynthetic ecosystems. The InterRidge <span class="hlt">Vents</span> Database lists only 3 confirmed (visualized) and 35 inferred (plume evidence) active <span class="hlt">sites</span> along the ~21,000 km of CARs. Here, we report on a multi-year effort to locate and characterize <span class="hlt">hydrothermal</span> activity on two 1st-order segments of the Australian-Antarctic Ridge that are perhaps more isolated from other known <span class="hlt">vent</span> fields than any other <span class="hlt">vent</span> <span class="hlt">site</span> on the Mid-Ocean Ridge. KR1 is a 300-km-long segment near 62°S/159°E, and KR2 a 90-km-long segment near 60°S/152.5°E. We used profiles collected by Miniature Autonomous Plume Recorders (MAPRs) on rock corers in March and December of 2011 to survey each segment, and an intensive CTD survey in Jan/Feb 2013 to pinpoint <span class="hlt">sites</span> and sample plumes on KR1. Optical and oxidation-reduction potential (ORP, aka Eh) anomalies indicate multiple active <span class="hlt">sites</span> on both segments. Seven profiles on KR2 found 3 <span class="hlt">sites</span>, each separated by ~25 km. Forty profiles on KR1 identified 13 <span class="hlt">sites</span>, some within a few km of each other. The densest <span class="hlt">site</span> concentration on KR1 occurred along a relatively inflated, 90-km-long section near the segment center. CTD tows covered 20 km of the eastern, most inflated portion of this area, finding two 6-km-long zones centered near 158.6°E and 158.8°E with multiple plume anomalies. Three ORP anomalies within 50 m of the seafloor indicate precise <span class="hlt">venting</span> locations. We call this area the Mujin "Misty Harbor" <span class="hlt">vent</span> field. <span class="hlt">Vent</span> frequency sharply decreases away from Mujin. 3He/heat ratios determined from 20 plume samples in the Mujin field were mostly <0.015 fM/J, indicative of chronic <span class="hlt">venting</span>, but 3 samples, 0.021-0.034 fM/J, are ratios typical of a recent eruption. The spatial density of <span class="hlt">hydrothermal</span> activity along KR1 and KR2 is similar to other intermediate-rate spreading ridges. We calculate the plume incidence (ph) along KR1 and KR2 as the mean of the fraction of MAPR casts detecting a plume in each 2nd-order segment. For all 6 segments, ph=0.37±0.25, consistent with the prediction of 0.33 from the global trend of ph for a spreading rate of 68 mm/yr.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.V21D..03M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.V21D..03M"><span id="translatedtitle">Metal Transport in <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Fluids Across an Eruption: 9°46'-9°52'N East Pacific Rise</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meana Prado, M. F.; Bryce, J. G.</p> <p>2012-12-01</p> <p>Elements carried in <span class="hlt">hydrothermal</span> fluids circulating within the oceanic crust constitute an important component of marine geochemical budgets and a significant mechanism for supporting unique chemosynthetic ecosystems along ridge axes. Temporal variabilities in <span class="hlt">hydrothermal</span> fluid compositions are well documented and linked with proximity to magmatic activity [1]. In fast spreading ridges, such as the East Pacific Rise, eruptions can change <span class="hlt">hydrothermal</span> fluid pathways, significantly and temporarily influencing metal transport if phase separation increases. Metal transport in fluids may be enhanced as well if <span class="hlt">hydrothermal</span> fluid circulation occurs through freshly emplaced basalt. A well documented magmatic eruption in late 2005/early 2006 disrupted the <span class="hlt">hydrothermal</span> system and offered the ideal opportunity to study how metal transport would be impacted and how long it would take for the <span class="hlt">hydrothermal</span> metal transport to return to pre-eruptive rates. Accordingly, we have carried out analyses of transition metals across the eruptive cycle on a time series of fluids collected from 10 <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> spanning ~8 km of ridge segment trending north-south along the axial summit trough. <span class="hlt">Hydrothermal</span> fluids were sampled from the same <span class="hlt">vents</span> in November 2004 (pre-eruptive) and then (post-eruptive) June 2006, November 2006, and December 2007. Analyses of Mn, Fe, Cu and Zn were carried out for all three <span class="hlt">hydrothermal</span> fluid fractions: dissolved via flame atomic adsorption, filtered particulates and 'dregs' via HR-ICP-MS. Resulting data, coupled with existing data (exit temperature, major elemental, and modeled peak pressure and temperature), allow for the identification of the key factors influencing metal abundance in high temperature fluids. Briefly, phase separation was the most significant process influencing metal abundance in dissolved fluids. Exceptions to this generalization were for the immediate post-eruptive fluids issued from Bio<span class="hlt">Vent</span>, the northernmost of the studied <span class="hlt">vents</span> whose metal contents are also likely controlled by extensive water-rock interactions (as indicated by elevated H2S contents). Along axis variations in chloride contents generally track in accordance with proximity to areas of greatest (or most recent) magma emplacement. Accordingly, along-axis variations in dissolved-fraction metal abundances were such that the highest dissolved loads were in areas significantly less impacted by the eruption (i.e. areas with minimal or no magmatic emplacement). As with chloride contents, the metal abundances in the dissolved fluids seemed to return to pre-eruptive levels within ~2 years following the eruption. [1] Von Damm, K. L. (2004), Geophys. Monogr. Ser.,148, pp. 285-304, AGU, Washington, DC.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GGG....14.3352T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GGG....14.3352T"><span id="translatedtitle">Cemented mounds and <span class="hlt">hydrothermal</span> sediments on the detachment surface at Kane Megamullion: A new manifestation of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tucholke, Brian E.; Humphris, Susan E.; Dick, Henry J. B.</p> <p>2013-09-01</p> <p>Long-lived detachment faults are now known to be important in tectonic evolution of slow-spreading mid-ocean ridges, and there is increasing evidence that fluid flow plays a critical role in development of detachment systems. Here we document a new manifestation of low-temperature <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> associated with the detachment fault that formed Kane Megamullion ˜3.3-2.1 m.y. ago in the western rift-valley wall of the Mid-Atlantic Ridge. <span class="hlt">Hydrothermal</span> effects on the detachment surface include (1) cemented mounds of igneous rock and chalk debris containing <span class="hlt">hydrothermal</span> Mn oxides and Fe oxyhydroxides, and (2) layered deposits of similar Fe-Mn minerals ± interbedded chalks. Mounds are roughly conical, ˜1-10 m high, and contain primarily basalts with lesser gabbro, serpentinite, and polymict breccia. The layered Fe-Mn-rich sediments are flat-bedded to contorted and locally are buckled into low-relief linear or polygonal ridges. We propose that the mounds formed where <span class="hlt">hydrothermal</span> fluids discharged through the detachment hanging wall near the active fault trace. <span class="hlt">Hydrothermal</span> precipitates cemented hanging-wall debris and welded it to the footwall, and this debris persisted as mounds as the footwall was exhumed and surrounding unconsolidated material sloughed off the sloping detachment surface. Some of the layered Fe-Mn-rich deposits may have precipitated from fluids discharging from the hanging-wall <span class="hlt">vents</span>, but they also precipitated from low-temperature fluids <span class="hlt">venting</span> from the exposed footwall through overlying chalks. Observed natural disturbance and abnormally thin hydrogenous Fe-Mn crusts on some contorted, <span class="hlt">hydrothermal</span> Fe-Mn-rich chalks on ˜2.7 Ma crust suggest diffuse <span class="hlt">venting</span> that is geologically recent. Results of this study imply that there are significant fluid pathways through all parts of detachment systems and that low-temperature <span class="hlt">venting</span> through fractured detachment footwalls may continue for several million years off-axis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFMOS43B0556H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFMOS43B0556H"><span id="translatedtitle">Laser-induced Native Fluorescence Detection of Organic Molecules in <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Rocks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harju, E.; Kidd, R. D.; Bhartia, R.; Conrad, P. G.</p> <p>2004-12-01</p> <p>We have developed a Multi-channel Deep Ultraviolet Excitation (McDuve) fluorescence detector that has been deployed at several Pacific <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> [1]. The in situ McDuve detector was able to detect organic molecules at the <span class="hlt">vent</span> <span class="hlt">site</span> on rock surfaces and in the water, the signatures being distinguishable one from the other. The McDuve fluorescence detector uses a 224.3 nm helium-silver hollow cathode laser to induce native fluorescence from a sample. Spectral separation is achieved with optical band-pass filters which are coupled to photomultiplier tubes (PMTs) for detection. Samples were recovered at the <span class="hlt">vent</span> <span class="hlt">sites</span> and returned from the expedition for bench-top analysis for correlation of the McDuve observations with standard analytical tools-GCMS and X-ray diffraction (for mineralogical ID), as well as with a bench-top version of the McDuve fluorescence detector. Here we report the corroborative results of the laboratory studies. Several preserved samples were subjected to 224.3 nm ultraviolet excitation under wet and dry conditions. Organic molecules were detected on the wet samples analyzed in the lab, corroborating the in situ McDuve data. The fluorescence emission wavelengths associated with the detected organic molecules suggest they are 3-5 ring polycyclic aromatic hydrocarbons [2,3]. The samples were also pyrolized at 500 ºC to decompose any organic molecules present and subsequently reanalyzed. This McDuve analysis revealed a significant decrease in laser induced native fluorescence, a result consistent with the pyrolytic decomposition of the organic content of the rock samples. [1] Conrad, P.G., A.L. Lane, R. Bhartia, W. Hug, (March 2004) Optical Detection of Organic Chemical Biosignatures at <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> 35th Lunar Plan. Sci. XXXV, 2055. [2] Karcher, W. (1985), Spectral Atlas of Polycyclic Aromatic Compounds, vol. I, Kluwer Academic Publishing Company, Dordrecht, Holland. [3] Bhartia, R., McDonald, G.D., Salas, E.C., Hug, W., Reid, R., Conrad, P.G., (2004) A Model to Differentiate Organic Compounds Based on UV Fluorescence Spectroscopy, Intl. J. Astrobiology, Suppl. 1, 115-116</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3483289','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3483289"><span id="translatedtitle">Microdistribution of Faunal Assemblages at Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> in the Southern Ocean</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Marsh, Leigh; Copley, Jonathan T.; Huvenne, Veerle A. I.; Linse, Katrin; Reid, William D. K.; Rogers, Alex D.; Sweeting, Christopher J.; Tyler, Paul A.</p> <p>2012-01-01</p> <p>Chemosynthetic primary production by microbes supports abundant faunal assemblages at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, with zonation of invertebrate species typically occurring along physico-chemical gradients. Recently discovered <span class="hlt">vent</span> fields on the East Scotia Ridge (ESR) in the Southern Ocean represent a new province of <span class="hlt">vent</span> biogeography, but the spatial dynamics of their distinct fauna have yet to be elucidated. This study determines patterns of faunal zonation, species associations, and relationships between faunal microdistribution and <span class="hlt">hydrothermal</span> activity in a <span class="hlt">vent</span> field at a depth of 2,400 m on the ESR. Remotely operated vehicle (ROV) dives obtained high-definition imagery of three chimney structures with varying levels of <span class="hlt">hydrothermal</span> activity, and a mosaic image of >250 m2 of seafloor co-registered with temperature measurements. Analysis of faunal microdistribution within the mosaiced seafloor reveals a consistent pattern of faunal zonation with increasing distance from <span class="hlt">vent</span> sources and peak temperatures. Assemblages closest to <span class="hlt">vent</span> sources are visibly dominated by a new species of anomuran crab, Kiwa n. sp. (abundance >700 individuals m?2), followed by a peltospiroid gastropod (>1,500 individuals m?2), eolepadid barnacle (>1,500 individuals m?2), and carnivorous actinostolid anemone (>30 individuals m?2). Peripheral fauna are not dominated by a single taxon, but include predatory and scavenger taxa such as stichasterid seastars, pycnogonids and octopus. Variation in faunal microdistribution on chimneys with differing levels of activity suggests a possible successional sequence for <span class="hlt">vent</span> fauna in this new biogeographic province. An increase in ?34S values of primary consumers with distance from <span class="hlt">vent</span> sources, and variation in their ?13C values also indicate possible zonation of nutritional modes of the <span class="hlt">vent</span> fauna. By using ROV videography to obtain a high-resolution representation of a <span class="hlt">vent</span> environment over a greater extent than previous studies, these results provide a baseline for determining temporal change and investigations of processes structuring faunal assemblages at Southern Ocean <span class="hlt">vents</span>. PMID:23144754</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS51E..08W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS51E..08W"><span id="translatedtitle">A New Species of the Genus Kiwa (Decapoda: Anomura) from the <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> of the Australia-Antarctic Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Won, Y. J.; Lee, S. H.; Lee, W. K.</p> <p>2014-12-01</p> <p>Due to extreme weather conditions and remoteness to access, the great part of the Southern Ocean remains to be explored. Therefore, little is known about the Circum-Antarctic Ridge (CAR) system and its <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystem underlying the Southern Ocean. We report the first discovery of a new deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field and a new anomuran species from the Australia-Antarctic Ridge (AAR), the highest latitude (62°S; 158°E) explored in the Southern Ocean up to date. At this <span class="hlt">site</span>, a new anomuran species which belongs to the genus Kiwa known as 'yeti crabs' was found. Morphologically, this species has characteristics of the genus Kiwa, including fifth pereopod inserted below sterna plastron, third sternite strongly produced anteriorly, and eyes extremely reduced. However, the new species differs from the other known species of Kiwa, K. hirsuta and K. puravida, showing relatively short rostrum and slender dactylus on second to fourth pereopods. Phylogenetic analysis using DNA sequences of eight genetic loci also supported the result of morphological analysis, confirming this species as a new Kiwa species, Kiwa n. sp. In addition, phylogenetic tree revealed the evolutionary relationship among the Kiwa species, presenting the Kiwa n. sp. as the sister species to K. puravida which inhabits the methane cold seep on the Pacific continental slope off Costa Rica. Considering the geography and the physicochemical environment, this unlikely result casts a mystery to be solved through further taxon sampling particularly from as-yet-unexplored <span class="hlt">vents</span> and seeps. Discovery of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> and Kiwa n. sp. from the AAR segment is significant because this <span class="hlt">site</span> is located in the high latitude of the southern hemisphere and it is the region affected by the Antarctic Circumpolar Current (ACC). Future research on the relation of Kiwa n. sp. and the other Kiwa species affected by the ACC will provide an idea about the biogeography and the evolutionary connections of the <span class="hlt">vent</span> faunas in the CAR system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.V51C1509D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.V51C1509D"><span id="translatedtitle">Extreme Spatial Variability in Microbial Mat Communities from Submarine <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> Located at Multiple Volcanoes along the Mariana Island Arc</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Davis, R. E.; Moyer, C. L.</p> <p>2005-12-01</p> <p>Volcanic arc systems are the most active tectonic feature in the world, but are among the least studied. The Western Pacific contains ~20,000 km of volcanic arcs, of which only ~2% have been systematically surveyed. The lack of comprehensive knowledge of volcanic arcs is compounded by the incredible variability found in relatively short distances. The complex source history of <span class="hlt">hydrothermal</span> fluids and the variable depths of seamounts found in island arc systems result in highly variable <span class="hlt">vent</span> chemistries and therefore unique microbial habitats within relatively short distances. The Mariana Island Arc was surveyed in 2003 and areas with suspected <span class="hlt">hydrothermal</span> activities were identified for targeted remote operating vehicle (ROV) exploration and sampling in 2004. Sixteen microbial mat samples from five seamounts ranging from 145-1742 mbsl and from ambient to 222°C were collected and analyzed with quantitative PCR (Q-PCR), cluster analysis of terminal restriction length polymorphism (T-RFLP) community fingerprints, and by clone library analysis of small subunit ribosomal rDNA genes. The microbial mat communities from the Mariana Island Arc exhibit greater spatial variability within their community structure than microbial mats sampled from mid-ocean ridge or hotspot <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> from a comparable scale. Microbial communities from the summit of NW Eifuku Volcano are dominated by putative iron-oxidizing phylotypes at the Yellow Top and Yellow Cone <span class="hlt">Vent</span> <span class="hlt">sites</span>, but are dominated by sulfur-oxidizing ?-Proteobacteria at the Champagne <span class="hlt">Vent</span> <span class="hlt">site</span>. Mats collected at the Mat City <span class="hlt">Vent</span> <span class="hlt">site</span> on E Diamante Seamount contained nearly three times as much biomass as any other mat sample collected, and is dominated by a Planctomyces phylotype. <span class="hlt">Hydrothermal</span> sediments at the Fish Spa <span class="hlt">site</span> located on Daikoku Seamount contained the second highest biomass detected and supported a large community of flatfish indicating a direct route for biomass being channeled up the food chain. The microbial community at Fish Spa consists of a highly diverse assemblage of Bacteroidetes, ?-Proteobacteria and Firmicutes. While in contrast, the microbial mat at the Iceberg <span class="hlt">Vent</span> <span class="hlt">site</span> on NW Rota I is dominated by a single phylotype of ?-Proteobacteria.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25748345','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25748345"><span id="translatedtitle">Mercury accumulation in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mollusks from the southern Tonga Arc, southwestern Pacific Ocean.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lee, Seyong; Kim, Se-Joo; Ju, Se-Jong; Pak, Sang-Joon; Son, Seung-Kyu; Yang, Jisook; Han, Seunghee</p> <p>2015-05-01</p> <p>We provide the mercury (Hg) and monomethylmercury (MMHg) levels of the plume water, sulfide ore, sediment, and mollusks located at the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields of the southern Tonga Arc, where active volcanism and intense seismic activity occur frequently. Our objectives were: (1) to address the potential release of Hg from <span class="hlt">hydrothermal</span> fluids and (2) to examine the distribution of Hg and MMHg levels in <span class="hlt">hydrothermal</span> mollusks (mussels and snails) harboring chemotrophic bacteria. While high concentrations of Hg in the sediment and Hg, As, and Sb in the sulfide ore indicates that their source is likely <span class="hlt">hydrothermal</span> fluids, the MMHg concentration in the sediment was orders of magnitude lower than the Hg (<0.001%). It suggests that Hg methylation may have not been favorable in the <span class="hlt">vent</span> field sediment. In addition, Hg concentrations in the mollusks were much higher (10-100 times) than in other <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments, indicating that organisms located at the Tonga Arc are exposed to exceedingly high Hg levels. While Hg concentration was higher in the gills and digestive glands than in the mantles and residues of snails and mussels, the MMHg concentrations in the gills and digestive glands were orders of magnitude lower (0.004-0.04%) than Hg concentrations. In summary, our results suggest that the release of Hg from the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields of the Tonga Arc and subsequent bioaccumulation are substantial, but not for MMHg. PMID:25748345</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.B12B..04H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.B12B..04H"><span id="translatedtitle">Microbial anaerobic methane cycling in the subseafloor at the Von Damm <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field, Mid-Cayman Rise</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Huber, J. A.; Reveillaud, J. C.; Stepanauskas, R.; McDermott, J. M.; Sylva, S. P.; Seewald, J.</p> <p>2013-12-01</p> <p>The Mid-Cayman Rise (MCR) is Earth's deepest and slowest spreading mid-ocean ridge located in the western Caribbean. With an axial rift valley floor at a depth of ~4200-6500 m, it represents one of the deepest sections of ridge crest worldwide. In 2009, the world's deepest <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> (Piccard at 4960 m) and an ultramafic-influenced system only 20 km away on top of an oceanic core complex (Von Damm at 2350 m) were discovered along the MCR. Each <span class="hlt">site</span> is hosted in a distinct geologic setting with different thermal and chemical regimes. The Von Damm <span class="hlt">site</span> is a particularly interesting location to examine chemolithoautotrophic subseafloor microbial communities due to the abundant hydrogen, methane, and organic compounds in the <span class="hlt">venting</span> fluids. Here, we used a combination of stable isotope tracing, next-generation sequencing, and single cell techniques to determine the identity, activity, and genomic repertoire of subseafloor anaerobic archaea involved in methane cycling in <span class="hlt">hydrothermal</span> fluids <span class="hlt">venting</span> at the Von Damm <span class="hlt">site</span>. Molecular sequencing of phylogenetic marker genes revealed the presence of diverse archaea that both generate and consume methane across a geochemical and thermal spectrum of <span class="hlt">vents</span>. Stable isotope tracing experiments were used to detect biological utilization of formate and dissolved inorganic carbon, and methane generation at 70 °C under anaerobic conditions. Results indicate that methanogenesis with formate as a substrate is occurring at 70 °C at two Von Damm <span class="hlt">sites</span>, Ginger Castle and the Main Orifice. The results are consistent with thermodynamic predictions for carbon speciation at the temperatures encountered at the ultramafic-hosted Von Damm, where formate is predicted to be thermodynamically stable, and may thus serve as a an important source of carbon. Diverse thermophilic methanogenic archaea belonging to the genera Methanothermococcus were detected at all <span class="hlt">vent</span> <span class="hlt">sites</span> with both 16S rRNA tag sequencing and single cell sorting. Other methanogenic archaea are also present, including the hyperthermophile Methanopyrus, as well as methanogens that can use acetate, methanol, and other simple carbon compounds for methane generation, such as the genera Methanosaeta and Methermicoccus. In addition, uncultivated lineages related to putative anaerobic methane cycling archaea were detected in the fluids. These include the GOM Arc I clade within the Methanosarcinales, a group previously described from Gulf of Mexico methane seeps and thought to be methanogenic, as well as the ANME-1 and ANME-2 lineages, which are likely anaerobically oxidizing methane. On-going metagenomic sequencing of both mixed microbial communities and single cells from <span class="hlt">venting</span> fluids will reveal the genomic repertoire, evolutionary relationships, and adaptations of these unique methane-cycling anaerobic archaea in the subseafloor at the Von Damm <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://arxiv.org/pdf/1304.6127.pdf','EPRINT'); return false;" href="http://arxiv.org/pdf/1304.6127.pdf"><span id="translatedtitle">The potential for photosynthesis in <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>: a new avenue for life in the Universe?</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Perez, Noel; Martin, Osmel; Leiva-Mora, Michel</p> <p>2013-01-01</p> <p>We perform a quantitative assessment for the potential for photosynthesis in <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the deep ocean. The photosynthetically active radiation in this case is from geothermal origin: the infrared thermal radiation emitted by hot water, at temperatures ranging from 473 up to 673 K. We find that at these temperatures the photosynthetic potential is rather low in these ecosystems for most known species. However, species which a very high efficiency in the use of light and which could use infrared photons till 1300nm, could achieve good rates of photosynthesis in <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. These organisms might also thrive in deep <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in other planetary bodies, such as one of the more astrobiologically promising Jupiter satellites: Europa.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006DSRI...53..726L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006DSRI...53..726L"><span id="translatedtitle">Spatial organization of food webs along habitat gradients at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on Axial Volcano, Northeast Pacific</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Levesque, Christian; Kim Juniper, S.; Limén, Helene</p> <p>2006-04-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are characterized by steep spatial gradients and high temporal variability in habitat conditions. This leads to the organization of species distribution along spatial habitat gradients, which may constrain food resource utilization and food web structure. We conducted a stable-isotope-based study to test the hypothesis that food resource utilization is constrained by spatial habitat variability at diffuse <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on Axial Volcano, Northeast Pacific. Our study included the ten most biomass-prominent species and considered the temporal change in food web structure at recently created <span class="hlt">vent</span> <span class="hlt">sites</span> during three consecutive years. We related species average stable isotopic composition to their position between the center and the periphery of <span class="hlt">vent</span> <span class="hlt">sites</span>, using previously published data. Species spread widely along the ?13C axis, and showed a small variability in ?15N. This indicates that most species partition food resources between isotopically different carbon sources, and that they are not organized along predator-prey trophic chains. Particulate organic matter (POM) stable isotopic composition from a concomitant study corresponds to the signature of the expected diet for most organisms. Species average ?13C was significantly correlated to their relative position between the center and the periphery of <span class="hlt">vent</span> <span class="hlt">sites</span>. We relate this spatial variability in species isotopic composition to variability in the isotopic signature of both dissolved inorganic carbon (DIC) and POM. This spatial isotopic signal of consumers reveals the spatial structuring of food (POM) production and its consumption by the fauna. Accrual of species during the development of diffuse <span class="hlt">sites</span> increased the inter-specific spread in ?13C, but did not increase the range in ?15N. Our results show that the spatial organization of species distribution results in a fragmented food web where species partition POM food resources according to their position in space. Shaping of species distribution by habitat gradients therefore constrains food web structure and the occurrence of predator-prey and competitive interactions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/14676368','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/14676368"><span id="translatedtitle">Organics in chimneys and water samples from deep-sea <span class="hlt">hydrothermal</span> systems: implications for sub-<span class="hlt">vent</span> biosphere.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Horiuchi, Tsukasa; Kobayashi, Kensei; Takano, Yoshinori; Marumo, Katsumi; Nakashima, Miwako; Yamagishi, Akihiko; Ishibashi, Jun-ichiro; Urabe, Tetsuro</p> <p>2003-10-01</p> <p>Searching for life in extreme terrestrial environments can be a model of that for extraterrestrial life. Submarine <span class="hlt">hydrothermal</span> system is one of promising <span class="hlt">sites</span> for the frontier of life on the earth. Here seawater and <span class="hlt">vent</span> chimnies were collected from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> at Suiyo Seamount, Izu-bonin arc, Pacific Ocean as a part of Archaean Park Project. Pure seawater sample of 300 degrees C (purity>97%) could be collected. Dissolved and total hydrolyzable amino acids were determined by ion-exchange HPLC, and their enantiomeric ratio was measured by reversed-phase HPLC for the first time. Glycine and serine were two most abundant amino acids, followed by other proteinous amino acids such as alanine, glutamic acid and aspartic acid. Non-proteinous amino acids were detected as minor constituents. Most of the amino acids detected were of the L-form. Thus amino acids of abiotic origin were quite minor, and most of the amino acids detected were formed biologically. These results, together with analytical results of the <span class="hlt">vent</span> chimney samples, suggest that there is active microbial activities near the <span class="hlt">hydrothermal</span> systems. PMID:14676368</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.S41A0939L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.S41A0939L"><span id="translatedtitle">The study of active submarine volcanoes and <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the Southernmost Part of Okinawa Trough</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Y.; Tsai, C.; Lee, C.</p> <p>2004-12-01</p> <p>The study area is located in the Southernmost Part of Okinawa Trough (SPOT), which is a back-arc basin formed by extension of Eurasian plate. Previous research indicated two extensional stages in SPOT area. Many normal-fault structures were come into existence during both extensional processes. The SPOT is presently in an activity tectonic episode. Therefore, the area becomes a frequent earthquake and abundant magmatism. The purpose of this study is to discuss which relationship between tectonics, submarine volcanoes and <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in SPOT area. The investigations are continued from 1998 to 2004, we have found at least twelve active <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in study area. Compare the locations <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> with fault systems, we find both of them have highly correlated. We can distinguish them into two shapes, pyramidal shape and non-pyramidal shape. According to plumes height, we are able to divide these <span class="hlt">vents</span> into two groups near east longitude 122.5° . East of this longitude, the <span class="hlt">hydrothermal</span> plumes are more powerful and west of it are the weaker. This is closely related to the present extensional axis (N80° E) of the southern part of the Okinawa Trough. This can be explained the reason of why the more powerful <span class="hlt">vents</span> coming out of the east group. The east group is associated with the present back-arc spreading system. West of 122.5° , the spreading system are in a primary stage. The andesitic volcanic island, the Turtle Island, is a result of N60° E extensional tectonism with a lot of faults. Besides the pyramidal shape, this can be proved indirectly. The <span class="hlt">vents</span> located in the west side were occurred from previous extensional faults and are weaker than the eastern. Therefore, we suggest that if last the extension keeps going on, the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> located at the west side of the longitude 122.5° will be intensified.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2698363','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2698363"><span id="translatedtitle">Diversity and Abundance of Ammonia-Oxidizing Archaea in <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Chimneys of the Juan de Fuca Ridge? †</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wang, Shufang; Xiao, Xiang; Jiang, Lijing; Peng, Xiaotong; Zhou, Huaiyang; Meng, Jun; Wang, Fengping</p> <p>2009-01-01</p> <p>The abundance and diversity of archaeal ammonia monooxygenase subunit A (amoA) genes from <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimneys at the Juan de Fuca Ridge were investigated. The majority of the retrieved archaeal amoA sequences exhibited identities of less than 95% to those in the GenBank database. Novel ammonia-oxidizing archaea may exist in the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments. PMID:19395559</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.V72A1288D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.V72A1288D"><span id="translatedtitle">A Retrievable Mineral Microcosm for Examining Microbial Colonization and Mineral Precipitation at Seafloor <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dunn, E. E.; Holloway, J. R.; Cary, S.; Voglesonger, K. M.; Ashbridge, D. A.; O'Day, P. A.</p> <p>2002-12-01</p> <p>Although seafloor <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments are known to support thriving ecosystems, the microscale physical and chemical environment suitable for microbial colonization and the identity of pioneering organisms is unknown. Because of the fragility of young chimneys and their ephemeral nature, novel methods for sample retrieval and analysis are required. The mineral microcosm consists of four titanium mesh chambers containing crushed minerals mounted on a titanium base that allows for fluid flow through the chambers. The chambers can be filled with different minerals or mineral mixtures (or no minerals) to supply different substrates for microbial colonization and different local microenvironments as minerals react with the surrounding fluids. The device sets on top of an active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> for a period of days to weeks to allow colonization and mineral reaction. The mineral microcosm was deployed during the Atlantis/Alvin Extreme 2001 Cruise (Oct.- Nov.,2001) to 9° 50'N on the East Pacific Rise a total of three times, for ~ 24, ~ 96, and ~ 48 hours each. It was deployed in two different environments, twice in lower temperature (<300°C), diffuse-flow environments and once (for ~96 hours) in a higher temperature black smoker environment (>350°C).Seed minerals included sulfides, sulfates, magnetite, apatite, and quartz, both individually and in mixtures. In the first 24-hour deployment, dissolution of anhydrite but not sulfide minerals within the chambers indicated high temperatures in chamber interiors and rapid reaction rates. Temperatures measured on chamber exteriors before retrieval ranged from 4° -98°C. The 96-hour deployment on a hot <span class="hlt">vent</span> (fluid ~370°C before deployment) resulted in extensive mineral precipitation and chimney growth inside the mineral chambers, on the outer surfaces of the chambers, and on the platform as a whole, creating micro-chimneys several centimeters tall. The young chimneys were mainly composed of pyrite with lesser amounts of chalcopyrite and sphalerite and with thin veneers of anhydrite on exterior surfaces in contact with seawater. Bulk trace element analyses of the newly formed chimneys show concentrations of Ag, Cd, Co, Cr, Mo, Ni, and Pb (up to ~200 ppm) but a lack of As, Sn, U, and W. On the last deployment in a polychaete-rich, diffuse-flow area (<span class="hlt">vent</span> temperature ~300°C), the microcosm was covered with biofilm and polychaete tubes had formed on the surface during the ~48 hours on the <span class="hlt">vent</span>. Temperatures at chamber exteriors had decreased to 16- 20°C, suggesting that the <span class="hlt">vent</span> was not vigorous enough to maintain a large flow through the chambers. Although no evidence for microbial colonization was obtained in these initial deployments, the device can simulate the mineralogy and temperature gradients of a natural <span class="hlt">hydrothermal</span> chimney. Young chimney samples of known age (~96 hours) obtained from the second deployment were analyzed by synchrotron X-ray computed tomography for porosity and mineralogy and compared with existing chimneys at these <span class="hlt">sites</span> (see companion abstract by Ashbridge, et al.).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24963774','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24963774"><span id="translatedtitle">Complete mitochondrial genome of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ghost shrimp Paraglypturus tonganus (Crustacea, Axiidea, Callianassidae).</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, Se-Joo; Kim, Jonguk; Ahn, Dong-Ha; Ju, Se-Jong; Min, Gi-Sik; Kim, Sanghee</p> <p>2016-03-01</p> <p>Ghost shrimps are burrowing decapods that serve as bioturbators and habitat providers in seafloor environments. The <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ghost shrimp, Paraglypturus tonganus, was collected from a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> in the Tonga Arc. This species has a mitochondrial genome (mitogenome) of 15,924?bp in length with an AT content of 66.1%. The mitogenome was identical to the typical gene arrangement and transcriptional polarity of the infraorder Axiidea. Paraglypturus tonganus showed 65.3-70.1% nucleotide similarity with the known mitogenomes of other axiid shrimps. These results are useful for understanding the phylogenetic relationships among the members of Axiidea within the decapods. PMID:24963774</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.B13C0512M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.B13C0512M"><span id="translatedtitle">High-pressure hydrogen respiration in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> samples from the deep biosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morgan-Smith, D.; Schrenk, M. O.</p> <p>2013-12-01</p> <p>Cultivation of organisms from the deep biosphere has met with many challenges, chief among them the ability to replicate this extreme environment in a laboratory setting. The maintenance of in situ pressure levels, carbon sources, and gas concentrations are important, intertwined factors which may all affect the growth of subsurface microorganisms. Hydrogen in particular is of great importance in <span class="hlt">hydrothermal</span> systems, but in situ hydrogen concentrations are largely disregarded in attempts to culture from these <span class="hlt">sites</span>. Using modified Hungate-type culture tubes (Bowles et al. 2011) within pressure-retaining vessels, which allow for the dissolution of higher concentrations of gas than is possible with other culturing methods, we have incubated <span class="hlt">hydrothermal</span> chimney and <span class="hlt">hydrothermally</span>-altered rock samples from the Lost City and Mid-Cayman Rise <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields. Hydrogen concentrations up to 15 mmol/kg have been reported from Lost City (Kelley et al. 2005), but data are not yet available from the recently-discovered Mid-Cayman <span class="hlt">site</span>, and the elevated concentration of 30 mmol/kg is being used in all incubations. We are using a variety of media types to enrich for various metabolic pathways including iron and sulfur reduction under anoxic or microaerophilic conditions. Incubations are being carried out at atmospheric (0.1 MPa), in situ (9, 23, or 50 MPa, depending on <span class="hlt">site</span>), and elevated (50 MPa) pressure levels. Microbial cell concentrations, taxonomic diversity, and metabolic activities are being monitored during the course of these experiments. These experiments will provide insight into the relationships between microbial activities, pressure, and gas concentrations typical of deep biosphere environments. Results will inform further culturing studies from both fresh and archived samples. References cited: Bowles, M.W., Samarkin, V.A., Joye, S.B. 2011. Improved measurement of microbial activity in deep-sea sediments at in situ pressure and methane concentration. Limnology and Oceanography Methods 9:499-506 Kelley, D.S., Karson, J.A., Früh-Green, G.L., Yoerger, D.R., Shank, T.M., et al. 2005. A Serpentinite-Hosted Ecosystem: The Lost City <span class="hlt">Hydrothermal</span> Field. Science 307:1428-1434</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://folk.uio.no/hensven/Svensen_etal_GSL_06.pdf','EPRINT'); return false;" href="http://folk.uio.no/hensven/Svensen_etal_GSL_06.pdf"><span id="translatedtitle">Journal of the Geological Society, London, Vol. 163, 2006, pp. 671682. Printed in Great Britain. Structure and evolution of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> complexes in the Karoo Basin,</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Svensen, Henrik</p> <p></p> <p>. 671 Structure and evolution of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> complexes in the Karoo Basin, South Africa HENRIK the Karoo Basin, extrusive lava sequences and <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> complexes. These last are pipe of the basin. Detailed mapping of two sediment-dominated <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> complexes shows</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://folk.uio.no/hensven/Svensen_etal_GSL_Discussion07.pdf','EPRINT'); return false;" href="http://folk.uio.no/hensven/Svensen_etal_GSL_Discussion07.pdf"><span id="translatedtitle">Journal of the Geological Society, London, Vol. 164, 2007, pp. 477479. Printed in Great Britain. Discussion on structure and evolution of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> complexes in the</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Svensen, Henrik</p> <p></p> <p>. 477 Discussion on structure and evolution of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> complexes in the Karoo Basin, South the paper by Svensen et al. (2006) on South African <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> within the Karoo Basin, particularly for their interest in our paper on <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> complexes in the Karoo Basin (Svensen et al. 2006). Based</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6165743','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6165743"><span id="translatedtitle">Subtidal gastropods consume sulfur-oxidizing bacteria: evidence from coastal <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Stein, J.L.</p> <p>1984-02-17</p> <p>The black abalone (Haliotis cracherodii), a commercially important shallow-water gastropod common off White Point, Southern California, is found frequently at subtidal <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> within mats of filamentous sulfur-oxidizing bacteria. Foraging <span class="hlt">vent</span> abalones actively consume the bacteria and confine their nightly feeding forays to bacterial mats surrounding the <span class="hlt">vents</span>. The growth of abalones consuming the sulfur bacteria exceeds that of control individuals consuming microalgae and is comparable to reported growth rates of abalones consuming macroalgae. Thus, off White Point, the black abalone may derive a portion of its nutrition from the subsidy of geothermal energy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.U14C..05E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.U14C..05E"><span id="translatedtitle">New Frontiers in Arctic Exploration: Autonomous Location and Sampling of <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> Under the Ice at Earth's Slowest Spreading Ridge (IPY Project 173)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Edmonds, H. N.; Reves-Sohn, R.; Singh, H.; Shank, T. M.; Humphris, S.; Seewald, J.; Akin, D.; Bach, W.; Nogi, Y.; Pedersen, R.</p> <p>2006-12-01</p> <p>As part of IPY project #173, we are planning an international expedition for 2007 to locate and study <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the ultraslow-spreading Gakkel Ridge, at depths greater than 4000 m beneath the permanent ice cap. This effort necessitates the development of novel exploration technologies, because the Gakkel Ridge rift valley is inaccessible to traditional deep submergence tools. With funding from NASA, NSF, and the private sector we have developed two new autonomous underwater vehicles that will find and map <span class="hlt">hydrothermal</span> plumes in the water column, trace the buoyant plume stem to the seafloor source, and then map, photograph, and collect samples from the <span class="hlt">vent</span> <span class="hlt">sites</span>. The Gakkel Ridge is a key target for <span class="hlt">hydrothermal</span> exploration not only because of its spreading rate but also because its geographic and hydrographic isolation from other portions of the mid-ocean ridge system have important implications for novel endemic <span class="hlt">vent</span> fauna. Our major scientific themes are the geological diversity and biogeography of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the Arctic mid-ocean ridge system. Our major technology theme is autonomous exploration and sample return with an explicit mandate to develop techniques and methods for eventual use in astrobiology missions to search for life under the ice covered oceans of Europa, a moon of Jupiter. In addition to the US-led Gakkel Ridge expedition, a Norway-led expedition will target <span class="hlt">sites</span> in seasonally ice-free water over the Mohns Ridge. The results of these two expeditions will be combined to reveal systematic patterns regarding biogeography (through both community-level and genetic-level investigations) of <span class="hlt">vent</span>-endemic fauna, to study the differences between basalt vs. peridotite hosted <span class="hlt">vent</span> fields, and to improve our understanding of <span class="hlt">hydrothermal</span> circulation at ultra- slow spreading plate boundaries where amagmatic extension and long-lived faulting predominate. The expeditions will provide educational and outreach activities through the award-winning Dive and Discover (www.divediscover.whoi.edu) web <span class="hlt">site</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004GMS...144..213P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004GMS...144..213P"><span id="translatedtitle">Significance of polysaccharides in microbial physiology and the ecology of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pysz, Marybeth A.; Montero, Clemente I.; Chhabra, Swapnil R.; Kelly, Robert M.; Rinker, Kristina D.</p> <p></p> <p>Hyperthermophilic microorganisms (those with maximum growth temperatures of 90°C and above) are known to inhabit deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments and are suspected of being present in the associated subsurface biosphere. One characteristic of the growth physiology of many heterotrophic hyperthermophiles is the capacity to use complex polysaccharides (e.g., ?- and ?-linked glucans as well as non-glucan hemicellulases) as carbon and energy sources. Polysaccharides may also play an important ecological role in the deep-sea subsurface biosphere as the structural elements of biofilms harboring both heterotrophic and chemolithotrophic microorganisms, representing a range of growth temperatures. Genome sequence analysis of several hyperthermophiles indicates that the enzymatic machinery to synthesize and hydrolyze polysaccharides is present in this group of microorganisms. This is supported by the biochemical characteristics of glycosidases from hyperthermophiles in addition to the observation that several hyperthermophiles form biofilms in pure and co-culture. It remains to be seen if biofilms form the basis for a subsurface biosphere but this possibility seems likely given the physiological characteristics of several hyperthermophiles and mesophiles, representative of microorganisms previously isolated from <span class="hlt">vent</span> <span class="hlt">sites</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.B51D0416V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.B51D0416V"><span id="translatedtitle">Evidence for a Chemoautotrophically Based Food Web at Inactive <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> (Manus Basin)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van Dover, C. L.; Erickson, K.; Macko, S.</p> <p>2008-12-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> are ephemeral systems. When <span class="hlt">venting</span> shuts down, sulfide-dependent taxa die off, and non-<span class="hlt">vent</span> taxa can colonize the hard substrata. In Manus Basin (Papua New Guinea), where active and inactive sulfide mounds are interspersed, hydroids, cladorhizid sponges, barnacles, and bamboo sponges, and other invertebrate types may occupy inactive sulfide mounds. Carbon and nitrogen isotopic compositions of animals occupying inactive sulfide mounds are consistent with nutritional dependence on either chemoautotrophically or photosynthetically produced organic material, but sulfur isotopic compositions of these animals point to a chemoautotrophic source of sulfur from dissolved sulfide in <span class="hlt">vent</span> fluids rather than sulfur derived from seawater sulfate through photosynthesis. Given that suspension-feeding and micro- carnivorous invertebrates are the biomass dominants at inactive sulfide mounds, the primary source of chemoautotrophic nutrition is likely suspended particulates and organisms delivered from nearby active <span class="hlt">vents</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20533947','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20533947"><span id="translatedtitle">Isolated communities of Epsilonproteobacteria in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids of the Mariana Arc seamounts.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Huber, Julie A; Cantin, Holly V; Huse, Susan M; Welch, David B Mark; Sogin, Mitchell L; Butterfield, David A</p> <p>2010-09-01</p> <p>Low-temperature <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids represent access points to diverse microbial communities living in oceanic crust. This study examined the distribution, relative abundance, and diversity of Epsilonproteobacteria in 14 low-temperature <span class="hlt">vent</span> fluids from five volcanically active seamounts of the Mariana Arc using a 454 tag sequencing approach. Most <span class="hlt">vent</span> fluids were enriched in cell concentrations compared with background seawater, and quantitative PCR results indicated that all fluids were dominated by bacteria. Operational taxonomic unit-based statistical tools applied to 454 data show that all <span class="hlt">vents</span> from the northern end of the Mariana Arc grouped together, to the exclusion of southern arc seamounts, which were as distinct from one another as they were from northern seamounts. Statistical analysis also showed a significant relationship between seamount and individual <span class="hlt">vent</span> groupings, suggesting that community membership may be linked to geographical isolation and not geochemical parameters. However, while there may be large-scale geographic differences, distance is not the distinguishing factor in the microbial community composition. At the local scale, most <span class="hlt">vents</span> host a distinct population of Epsilonproteobacteria, regardless of seamount location. This suggests that there may be barriers to exchange and dispersal for these <span class="hlt">vent</span> endemic microorganisms at <span class="hlt">hydrothermal</span> seamounts of the Mariana Arc. PMID:20533947</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.P53E..09T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.P53E..09T"><span id="translatedtitle">Microbial community development in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the Earth and the Enceladus (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Takai, K.; Shibuya, T.; Sekine, Y.; Russell, M. J.</p> <p>2013-12-01</p> <p>Over the past 35 years, researchers have explored seafloor deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments around the globe and studied a number of microbial ecosystems. Bioinformatics and interdisciplinary geochemistry-microbiology approaches have provided new ideas on the diversity and community composition of microbial life living in deep-sea <span class="hlt">vents</span>. In particular, recent investigations have revealed that the community structure and productivity of chemolithotrophic microbial communities in the deep-sea <span class="hlt">hydrothermal</span> environments are controlled primarily by variations in the geochemical composition of <span class="hlt">hydrothermal</span> fluids. This was originally predicted by a thermodynamic calculation of energy yield potential of various chemolithotrophic metabolisms in a simulated <span class="hlt">hydrothermal</span> mixing zone. The prediction has been finally justified by the relatively quantitative geomicrobiological characterizations in various deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments all over the world. Thus, there should be a possible principle that the thermodynamic estimation of chemolithotrophic energy yield potentials could predict the realistic chemolithotrophic living community in any of the deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments in this planet. In 2005, a spacecraft Cassini discovered a water vapour jet plume from the sole pole area of the Saturnian moon Enceladus. The chemical composition analyses of Cassini's mass spectrometer strongly suggested that the Enceladus could host certain extent of extraterrestrial ocean beneath the surface ice sheet and possible ocean-rock <span class="hlt">hydrothermal</span> systems. In addition, a recent research has suggests that there is silica nanoparticles in Saturn's E-ring derived from the Enceladus plume. An experimental study simulating the reaction between chondritic material and alkaline seawater reveals that the formation of silica nanoparticles requires <span class="hlt">hydrothermal</span> reaction at high temperatures. Based on these findings, we attempt to built a model of possible <span class="hlt">hydrothermal</span> fluid/rock reactions and bioavailable energy composition in the mixing zones between the <span class="hlt">hydrothermal</span> fluid and the seawater in the Enceladus subsurface ocean. The results indicate that the pH of fluid should be highly alkaline and H2 concentration in the fluid is elevated up to several tens mM through the water/rock reaction. The physical and chemical condition of the extraterrestrial ocean environments points that the abundant bioavailable energy is obtained maximally from redox reactions based on CO2 and H2 but not from with other electron accepters such as sulfate and nitrate. In the low-temperature zones, the available energy of the Enceladus methanogenesis and acetogenesis is higher than those in any Earth's environment where the methanogens sustain the whole microbial ecosystem. Our model strongly suggests that the abundant living ecosystem sustained by hydrogenotrophic methanogensis and acetogenesis using planetary inorganic energy sources should be present in the Enceladus <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems and the ocean.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008E%26PSL.273..332G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008E%26PSL.273..332G"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> activity on the southern Mid-Atlantic Ridge: Tectonically- and volcanically-controlled <span class="hlt">venting</span> at 4 5°S</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>German, C. R.; Bennett, S. A.; Connelly, D. P.; Evans, A. J.; Murton, B. J.; Parson, L. M.; Prien, R. D.; Ramirez-Llodra, E.; Jakuba, M.; Shank, T. M.; Yoerger, D. R.; Baker, E. T.; Walker, S. L.; Nakamura, K.</p> <p>2008-09-01</p> <p>We report results from an investigation of the geologic processes controlling <span class="hlt">hydrothermal</span> activity along the previously-unstudied southern Mid-Atlantic Ridge (3-7°S). Our study employed the NOC (UK) deep-tow sidescan sonar instrument, TOBI, in concert with the WHOI (USA) autonomous underwater vehicle, ABE, to collect information concerning <span class="hlt">hydrothermal</span> plume distributions in the water column co-registered with geologic investigations of the underlying seafloor. Two areas of high-temperature <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> were identified. The first was situated in a non-transform discontinuity (NTD) between two adjacent second-order ridge-segments near 4°02'S, distant from any neovolcanic activity. This geologic setting is very similar to that of the ultramafic-hosted and tectonically-controlled Rainbow <span class="hlt">vent-site</span> on the northern Mid-Atlantic Ridge. The second <span class="hlt">site</span> was located at 4°48'S at the axial-summit centre of a second-order ridge-segment. There, high-temperature <span class="hlt">venting</span> is hosted in an ˜ 18 km 2 area of young lava flows which in some cases are observed to have flowed over and engulfed pre-existing chemosynthetic <span class="hlt">vent</span>-fauna. In both appearance and extent, these lava flows are directly reminiscent of those emplaced in Winter 2005-06 at the East Pacific Rise, 9°50'N and reference to global seismic catalogues reveals that a swarm of large (M 4.6-5.6) seismic events was centred on the 5°S segment over a ˜ 24 h period in late June 2002, perhaps indicating the precise timing of this volcanic eruptive episode. Temperature measurements at one of the <span class="hlt">vents</span> found directly adjacent to the fresh lava flows at 5°S MAR (Turtle Pits) have subsequently revealed <span class="hlt">vent</span>-fluids that are actively phase separating under conditions very close to the Critical Point for seawater, at ˜ 3000 m depth and 407 °C: the hottest <span class="hlt">vent</span>-fluids yet reported from anywhere along the global ridge crest.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26107940','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26107940"><span id="translatedtitle">Adaptations to <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Life in Kiwa tyleri, a New Species of Yeti Crab from the East Scotia Ridge, Antarctica.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Thatje, Sven; Marsh, Leigh; Roterman, Christopher Nicolai; Mavrogordato, Mark N; Linse, Katrin</p> <p>2015-01-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> in the Southern Ocean are the physiologically most isolated chemosynthetic environments known. Here, we describe Kiwa tyleri sp. nov., the first species of yeti crab known from the Southern Ocean. Kiwa tyleri belongs to the family Kiwaidae and is the visually dominant macrofauna of two known <span class="hlt">vent</span> <span class="hlt">sites</span> situated on the northern and southern segments of the East Scotia Ridge (ESR). The species is known to depend on primary productivity by chemosynthetic bacteria and resides at the warm-eurythermal <span class="hlt">vent</span> environment for most of its life; its short-range distribution away from <span class="hlt">vents</span> (few metres) is physiologically constrained by the stable, cold waters of the surrounding Southern Ocean. Kiwa tylerihas been shown to present differential life history adaptations in response to this contrasting thermal environment. Morphological adaptations specific to life in warm-eurythermal waters, as found on - or in close proximity of - <span class="hlt">vent</span> chimneys, are discussed in comparison with adaptations seen in the other two known members of the family (K. hirsuta, K. puravida), which show a preference for low temperature chemosynthetic environments. PMID:26107940</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4480985','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4480985"><span id="translatedtitle">Adaptations to <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Life in Kiwa tyleri, a New Species of Yeti Crab from the East Scotia Ridge, Antarctica</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Thatje, Sven; Marsh, Leigh; Roterman, Christopher Nicolai; Mavrogordato, Mark N.; Linse, Katrin</p> <p>2015-01-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> in the Southern Ocean are the physiologically most isolated chemosynthetic environments known. Here, we describe Kiwa tyleri sp. nov., the first species of yeti crab known from the Southern Ocean. Kiwa tyleri belongs to the family Kiwaidae and is the visually dominant macrofauna of two known <span class="hlt">vent</span> <span class="hlt">sites</span> situated on the northern and southern segments of the East Scotia Ridge (ESR). The species is known to depend on primary productivity by chemosynthetic bacteria and resides at the warm-eurythermal <span class="hlt">vent</span> environment for most of its life; its short-range distribution away from <span class="hlt">vents</span> (few metres) is physiologically constrained by the stable, cold waters of the surrounding Southern Ocean. Kiwa tylerihas been shown to present differential life history adaptations in response to this contrasting thermal environment. Morphological adaptations specific to life in warm-eurythermal waters, as found on – or in close proximity of – <span class="hlt">vent</span> chimneys, are discussed in comparison with adaptations seen in the other two known members of the family (K. hirsuta, K. puravida), which show a preference for low temperature chemosynthetic environments. PMID:26107940</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.8108D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.8108D"><span id="translatedtitle">Carbon fluxes from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> off Milos, Aegean Volcanic Arc, and the influence of <span class="hlt">venting</span> on the surrounding ecosystem.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dando, Paul; Aliani, Stefano; Bianchi, Nike; Kennedy, Hilary; Linke, Peter; Morri, Carla</p> <p>2014-05-01</p> <p>The island of Milos, in the Aegean Sea, has extensive <span class="hlt">hydrothermal</span> fields to the east and southeast of the island with additional <span class="hlt">venting</span> areas near the entrance to and within the central caldera. A calculation of the total area of the <span class="hlt">vent</span> fields, based on ship and aerial surveys, suggested that the <span class="hlt">hydrothermal</span> fields occupy 70 km2, twice the area previously estimated. The <span class="hlt">vents</span> ranged in water depth from the intertidal to 300 m. As a result of the low depths there was abundant free gas release: in places water boiled on the seabed. The stream of gas bubbles rising through the sandy seabed drove a shallow re-circulation of bottom seawater. The majority of the water released with the gas, with a mean pH of 5.5, was re-circulated bottom water that had become acidified in contact with CO2 gas and was often diluted by admixture with the vapour phase from the deeper fluids. The major component of the free gas, 80%, was CO2, with an estimated total flux of 1.5-7.5 x 1012 g a-1. The methane flux, by comparison, was of the order of 1010 g a.-1 Using methane as a tracer it was shown that the major gas export from the <span class="hlt">vents</span> was below the thermocline towards the southwest, in agreement with the prevailing currents. Areas of <span class="hlt">hydrothermal</span> brine seepage occurred between the gas <span class="hlt">vents</span> and occasional brine pools were observed in seabed depressions. Under relatively calm conditions, many of the brine seeps were covered by thick minero-bacterial mats consisting of silica and sulphur and surrounded by mats of diatoms and cyanobacteria. The minerals were not deposited in the absence of bacteria. Storms disrupted the mats, leading to an export of material to the surrounding area. Stable isotope data from sediments and sediment trap material suggested that exported POM was processed by zooplankton. The combined effects of the geothermal heating of the seabed, the large gas flux, variation in the <span class="hlt">venting</span> and the effect of the brine seeps had a dramatic effect on the surrounding ecosystem. The infaunal biomass and diversity were greatly reduced in the vicinity of the <span class="hlt">vents</span> (up to approximately 8 m away from the <span class="hlt">vents</span>) and seagrass cover was absent from the brine seeps. These changes were a consequence of high sediment temperatures, hydrogen sulphide concentrations, high or low salinities and sediment cementation. In contrast, the species diversity of the hard substrate epibiota surrounding the <span class="hlt">vents</span> was over twice as high as that at nearby areas of equivalent water depth, even though <span class="hlt">vent</span>-obligate fauna were absent. Sediment cementation, caused by reactions with the minerals in the <span class="hlt">vent</span> fluids, decreased the habitat for sediment infauna, but enhanced bioconstruction by coralline algae and corals, and hence habitat provision for epibenthic organisms. Since the water column was typical of the oligotrophic Aegean, with low chlorophyll and phytoplankton production, the diverse and enhanced benthic primary production, by cyanobacteria, diatoms and chemoautotropic bacteria and archaea, in the mats over the hot seeps was believed to provide a large diversity of nutritional niches for the epibenthos.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988DSRA...35.1833V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988DSRA...35.1833V"><span id="translatedtitle">Recruitment of marine invertebrates to hard substrates at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the East Pacific Rise and Galapagos spreading center</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Van Dover, Cindy Lee; Berg, Carl J.; Turner, Ruth D.</p> <p>1988-10-01</p> <p>Recruitment panels were placed at and near <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> communities at three <span class="hlt">sites</span> on the Galapagos spreading center and one <span class="hlt">site</span> on the East Pacific Rise at 21°N. Deployment periods ranged from 26 days (Clam Acres, 21°N) to 260-320 days (Rose Garden, Garden of Eden, Mussel Bed, GSC) to 1216 days (Clam Acres). Recruitment of gastropod post-larvae and juveniles was observed on arrays deployed at Clam Acres for 26 days. Regardless of length of deployment, populations of polychaetes, mollusks, and barnacles colonizing the panels were predominantly post-larval, juvenile, or sub-adult stages. We suggest that some combination of competition, migration, and predation maintains these populations in immature stages. Size distributions of individuals within a taxon on panels deployed for 1216 days are broad, suggesting intermittent or continuous recruitment in many of the <span class="hlt">vent</span>-associated species rather than a single episodic recruitment event. Folliculinid and foraminiferan protozoans were the most abundant eucaryotic organisms colonizing long-term deployments at Clam Acres. On the Galapagos spreading center, level of recruitment differed among the <span class="hlt">vent</span> <span class="hlt">sites</span>, with Rose Garden > Garden of Eden ? Mussel Bed. Recruitment of <span class="hlt">vent</span>-associated species was greater on panels placed within <span class="hlt">vent</span> communities compared to panels placed adjacent to these communities. This observation is consistent with the maintenance of <span class="hlt">vent</span> communities in discrete regions of <span class="hlt">hydrothermal</span> flux.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS22B..01B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS22B..01B"><span id="translatedtitle">On the global distribution of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields: One decade later</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beaulieu, S. E.; Baker, E. T.; German, C. R.</p> <p>2012-12-01</p> <p>Since the last global compilation one decade ago, the known number of active submarine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields has almost doubled. At the end of 2009, a total of 518 active <span class="hlt">vent</span> fields was catalogued, with about half (245) visually confirmed and others (273) inferred active at the seafloor. About half (52%) of these <span class="hlt">vent</span> fields are at mid-ocean ridges (MORs), 25% at volcanic arcs, 21% at back-arc spreading centers (BASCs), and 2% at intra-plate volcanoes and other settings. One third are in high seas, and the nations with the most known active <span class="hlt">vent</span> fields within EEZs are Tonga, USA, Japan, and New Zealand. The increase in known <span class="hlt">vent</span> fields reflects a number of factors, including increased national and commercial interests in seafloor <span class="hlt">hydrothermal</span> deposits as mineral resources. Here, we have comprehensively documented the percentage of strike length at MORs and BASCs that has been systematically explored for <span class="hlt">hydrothermal</span> activity. As of the end of 2009, almost 30% of the ~60,000 km of MORs had been surveyed at least with spaced vertical profiles to detect <span class="hlt">hydrothermal</span> plumes. A majority of the <span class="hlt">vents</span> discovered at MORs in the past decade occurred at segments with < 60 mm/yr full spreading rate. Discoveries at ultra-slow MORs in the past decade included the deepest known <span class="hlt">vent</span> (Beebe at Mid-Cayman Rise) and high-temperature black smoker <span class="hlt">vents</span> (e.g., Dragon at SWIR and Loki's Castle at Mohns Ridge), and the highest temperature <span class="hlt">vent</span> was measured at the slow-spreading S MAR (Turtle Pits). Using a previously published equation for the linear relationship between the number of active <span class="hlt">vent</span> fields per 100 km strike length (F_s) vs. weighted-average full spreading rate (u_s), we predicted 676 <span class="hlt">vent</span> fields remaining to be discovered at MORs. Even accounting for the lower F_s at slower spreading rates, almost half of the <span class="hlt">vents</span> that are predicted remaining to be discovered at MORs are at ultra-slow to slow spreading rates (< 40 mm/yr) and about 1/3 at intermediate rates (40-80 mm/yr). MOR regions that are little explored tend to be at high latitudes, such as the ultra-slow to slow spreading Arctic MORs (e.g., Kolbeinsey and Mohns Ridges), the ultra-slow American-Antarctic Ridge, and the intermediate spreading Pacific-Antarctic Ridge. Although a greater percentage of the ~11,000 km of BASCs has been surveyed for <span class="hlt">hydrothermal</span> activity, the discoveries at BASCs in the past decade were mainly at segments with intermediate to fast spreading rates. Using the same equation for F_s vs. u_s, we predicted 71 <span class="hlt">vent</span> fields remaining to be discovered at BASCs, and most are likely to be found at ultra-slow and slow spreading segments (e.g., Andaman Basin, and central to northern Mariana Trough). With 2/3 of our overall predicted total <span class="hlt">vent</span> fields at spreading ridges remaining to be discovered, we expect that the next decade of exploration will continue to yield new discoveries, leading to new insights into biogeography of <span class="hlt">vent</span> fauna and the global impacts of fluxes of heat and materials from <span class="hlt">vents</span> into our oceans.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70032871','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70032871"><span id="translatedtitle">Bottom sediments and pore waters near a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> in Lake Baikal (Frolikha Bay)</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Granina, L.Z.; Klerkx, J.; Callender, E.; Leermakers, M.; Golobokova, L.P.</p> <p>2007-01-01</p> <p>We discuss the redox environments and the compositions of bottom sediments and sedimentary pore waters in the region of a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> in Frolikha Bay, Lake Baikal. According to our results, the submarine <span class="hlt">vent</span> and its companion nearby spring on land originate from a common source. The most convincing evidence for their relation comes from the proximity of stable oxygen and hydrogen isotope compositions in pore waters and in the spring water. The isotope composition indicates a meteoric origin of pore waters, but their major- and minor-element chemistry bears imprint of deep water which may seep through permeable faulted crust. Although pore waters near the submarine <span class="hlt">vent</span> have a specific enrichment in major and minor constituents, <span class="hlt">hydrothermal</span> discharge at the Baikal bottom causes a minor impact on the lake water chemistry, unlike the case of freshwater geothermal lakes in the East-African Rift and North America. ?? 2007.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6956153','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6956153"><span id="translatedtitle">Fluid flow and sound generation at <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields. Doctoral thesis</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Little, S.A.</p> <p>1988-04-01</p> <p>Several experiments in this thesis examine methods to measure and monitor fluid flow from <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields. Simultaneous velocity temperature, and conductivity data were collected in the convective flow emanating from a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field located on the East Pacific rise. The horizontal profiles obtained indicate that the flow field approaches an ideal plume in the temperature and velocity distribution. Such parameters as total heat flow and maximum plume height can be estimated using either the velocity or the temperature information. The results of these independent calculations are in close agreement, yielding a total heat capacity and volume changes slightly alter the calculations applied to obtain these values. In Guaymas Basin, a twelve day time series of temperature data was collected from a point three centimeters above a diffuse <span class="hlt">hydrothermal</span> flow area. Using concurrent tidal gauge data from the town of Guaymas it is shown that the effects of tidal currents can be strong enough to dominate the time variability of a temperature signal at a fixed point in <span class="hlt">hydrothermal</span> flow and are a plausible explanation for the variations seen in the Guaymas Basin temperature data. The increase in power due to convected flow inhomogeneities, however, was lower in the near field than expected. Indirect evidence of <span class="hlt">hydrothermal</span> sound fields showing anomalous high power and low frequency noise associated with <span class="hlt">vents</span> is due to processes other than jet noise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS53C1062S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS53C1062S"><span id="translatedtitle">Seismicity at the Kairei <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Field Near the Rodriguez Triple Junction in the Indian Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sato, T.; Takata, H.; Imai, Y.; Mori, T.; Noguchi, Y.; Kono, A.; Yamada, T.; Shinohara, M.</p> <p>2014-12-01</p> <p>1. Introduction In the first segment of the central Indian Ridge from the Rodriguez triple junction, the Kairei <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field exists and extrudes <span class="hlt">hydrothermal</span> fluid with richer hydrogen content compared to other <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the world. Around the Kairei <span class="hlt">hydrothermal</span> field, serpentinized peridotite and troctolites, and gabbroic rocks were discovered. These deep-seated rocks exposed around the Kairei field may cause the enrichment of H2 in the Kairei fluids. At the Kairei field, a hydrogen-based subsurface microbial ecosystem and various <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> macrofauna were found. In the "TAIGA" Project (Trans-crustal Advection and In situ reaction of Global sub-seafloor Aquifer), this area is a representative field of "TAIGA" of hydrogen. To investigate how the deep-seated rocks (originally situated at several kilometers below seafloor) are uplifted and exposed onto seafloor, and the <span class="hlt">hydrothermal</span> fluids circulate in subsurface, we conducted a seismic refraction/reflection survey and seismicity observation with ocean bottom seismometers (OBSs). This presentation will show seismicity of the survey area. 2. Observation and results We conducted a seismic survey around the Kairei <span class="hlt">hydrothermal</span> field from January 27 to March 19 in 2013 using S/V Yokosuka of Jamstec. We used 21 OBSs. From the 50 days seismicity observation, we found many micro earthquakes in this area. A swarm of micro earthquakes exists at a location about 1 km northwest of the Kairei field. The swarm has a NNW-SSE strike, parallel to the ridge axis. The depth of the swarm is very shallow (~4 km from seafloor). This swarm may be related to the <span class="hlt">hydrothermal</span> activities of the Kairei field. At the first segment of the central Indian Ridge, many micro earthquakes occurred. The depth of these events is deeper than that of the swarm near the Kairei field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4077841','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4077841"><span id="translatedtitle">Comparative Population Structure of Two Deep-Sea <span class="hlt">Hydrothermal-Vent</span>-Associated Decapods (Chorocaris sp. 2 and Munidopsis lauensis) from Southwestern Pacific Back-Arc Basins</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Thaler, Andrew David; Plouviez, Sophie; Saleu, William; Alei, Freddie; Jacobson, Alixandra; Boyle, Emily A.; Schultz, Thomas F.; Carlsson, Jens; Van Dover, Cindy Lee</p> <p>2014-01-01</p> <p>Studies of genetic connectivity and population structure in deep-sea chemosynthetic ecosystems often focus on endosymbiont-hosting species that are directly dependent on chemical energy extracted from <span class="hlt">vent</span> effluent for survival. Relatively little attention has been paid to <span class="hlt">vent</span>-associated species that are not exclusively dependent on chemosynthetic ecosystems. Here we assess connectivity and population structure of two <span class="hlt">vent</span>-associated invertebrates—the shrimp Chorocaris sp. 2 and the squat lobster Munidopsis lauensis—that are common at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the western Pacific. While Chorocaris sp. 2 has only been observed at <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span>, M. lauensis can be found throughout the deep sea but occurs in higher abundance around the periphery of active <span class="hlt">vents</span> We sequenced mitochondrial COI genes and deployed nuclear microsatellite markers for both species at three <span class="hlt">sites</span> in Manus Basin and either North Fiji Basin (Chorocaris sp. 2) or Lau Basin (Munidopsis lauensis). We assessed genetic differentiation across a range of spatial scales, from approximately 2.5 km to more than 3000 km. Population structure for Chorocaris sp. 2 was comparable to that of the <span class="hlt">vent</span>-associated snail Ifremeria nautilei, with a single seemingly well-mixed population within Manus Basin that is genetically differentiated from conspecifics in North Fiji Basin. Population structure for Munidopsis lauensis was more complex, with two genetically differentiated populations in Manus Basin and a third well-differentiated population in Lau Basin. The unexpectedly high level of genetic differentiation between M. lauensis populations in Manus Basin deserves further study since it has implications for conservation and management of diversity in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystems. PMID:24983244</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16..208V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16..208V"><span id="translatedtitle">Previously unsuspected dietary habits of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fauna: the bactivorous shrimp Rimicaris hybisae can be carnivorous or even cannibalistic</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Versteegh, Emma; Van Dover, Cindy; Coleman, Max</p> <p>2014-05-01</p> <p>Most <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> support productive communities, with chemosynthetic bacteria at the base of the food web. They form a potentially important link in global geochemical cycles. However, few data yet exist on their significance in ocean biogeochemistry and related ecological processes. We present results on the structure of part of the food web around <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> of the Mid-Cayman Rise (MCR), revealing previously unknown life-history traits of the alvinocarid shrimp species Rimicaris hybisae. We also demonstrate that stable carbon isotope ratios (?13C values) are an excellent tracer of trophic positions in these ecosystems, in spite of recent findings arguing otherwise. Two <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields have been described at the ultra-slow spreading ridge of the MCR. These include the world's deepest <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> (Piccard field ~4985 m), which support a food web, which includes bactivorous shrimp and carnivorous anemones. The nearby Von Damm <span class="hlt">vent</span> field (~2300 m) supports a more complex food web, with more primary producers, and probably some influx of photosynthetically produced carbon. Rimicaris hybisae is abundant at both known MCR <span class="hlt">vent</span> fields and shows a high degree of spatial variability in population structure and reproductive features. In previous work it has been considered bactivorous. Large variations in tissue ?13C values remained largely unexplained, and it has been argued that ?13C values are not a good food web tracer in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystems. We observed that shrimp tended to be either in dense aggregations on active chimneys or more sparsely distributed, peripheral shrimp in ambient or near-ambient temperatures. With the hypothesis that varying ?13C values show real differences in food sources between individuals and that shrimp in different locales might have different diets, we collected shrimp from both environments at the Von Damm <span class="hlt">site</span> during E/V Nautilus (NA034, August 2013) and examined their gut contents. Stomach contents of all shrimp from dense aggregations at the Von Damm field (n=18) consisted of white, amorphous material that resembled bacteria. Sparsely distributed peripheral shrimp (~1 m from dense aggregations) had stomachs filled with fragments of crustacean exoskeleton (5/13), a mixture of bacteria-like material and crustacean exoskeleton (3/13), or bacteria-like material only (5/13). We then analyzed the ?13C, ?15N and ?34S compositions of the shrimp gut contents. We show that R. hybisae switches its diet from exclusively chemosynthetic bacteria to crustacea during its life history. This is reflected in dramatically lower ?13C values of shrimp tissues, and slightly elevated ?15N values. To further support our findings, measurements of ?34S values on the same individuals and their gut contents are ongoing. Our contribution to disentangling the food web around the MCR <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> fields helps quantify their carbon budget and determine their role in ocean carbon cycling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012BGD.....9.4177B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012BGD.....9.4177B"><span id="translatedtitle">Activity and abundance of denitrifying bacteria in the subsurface biosphere of diffuse <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> of the Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bourbonnais, A.; Juniper, S. K.; Butterfield, D. A.; Devol, A. H.; Kuypers, M. M. M.; Lavik, G.; Hallam, S. J.; Wenk, C. B.; Chang, B. X.; Murdock, S. A.; Lehmann, M. F.</p> <p>2012-04-01</p> <p>Little is known about nitrogen (N) transformations in general, and the elimination of N in particular, at diffuse <span class="hlt">vents</span> where anoxic <span class="hlt">hydrothermal</span> fluids have mixed with oxygenated crustal seawater prior to discharge. Oceanic N sinks that remove bio-available N ultimately affect chemosynthetic primary productivity in these ecosystems. Using 15N paired isotope techniques, we determined potential rates of fixed N-loss pathways (denitrification, anammox) and dissimilative nitrate reduction to ammonium (DNRA) in sulfidic <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids discharging from the subsurface at several <span class="hlt">sites</span> at Axial Volcano and the Endeavour Segment on the Juan de Fuca Ridge. We also measured physico-chemical parameters (i.e. temperature, pH, nutrients, H2S and N2O concentrations) as well as the biodiversity and abundance of chemolithotrophic nitrate-reducing, sulfur-oxidizing ?-proteobacteria (SUP05 cluster) using sequence analysis of amplified small subunit ribosomal RNA (16S rRNA) genes in combination with taxon-specific quantitative polymerase chain reaction (qPCR) assays. Denitrification was the dominant N-loss pathway in the subsurface biosphere of the Juan de Fuca Ridge, with rates of up to ~1000 nmol N l-1 day-1. In comparison, anammox rates were always <5 nmol N l-1 day-1 and below the detection limit at most of the <span class="hlt">sites</span>. DNRA rates were up to 152 nmol N l-1 day-1. These results suggest that bacterial denitrification out-competes anammox in sulfidic <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> waters. Taxon-specific qPCR revealed that ?-proteobacteria of the SUP05 cluster sometimes dominated the microbial community (SUP05/total bacteria up to 38%). Significant correlation existed between fixed N-loss (i.e., denitrification, anammox) rates and in-situ nitrate and dissolved inorganic nitrogen (DIN) deficits in the fluids, indicating that DIN availability may ultimately regulate N-loss in the subsurface. Based on our rate measurements, and on published data on <span class="hlt">hydrothermal</span> fluid fluxes and residence times, we estimated that, on average, ~10 Tg N yr-1 could globally be removed in the subsurface biosphere of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> systems, and could thus represent a small, but significant, fraction of the total marine N loss (240-400 Tg N yr-1).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012BGeo....9.4661B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012BGeo....9.4661B"><span id="translatedtitle">Activity and abundance of denitrifying bacteria in the subsurface biosphere of diffuse <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> of the Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bourbonnais, A.; Juniper, S. K.; Butterfield, D. A.; Devol, A. H.; Kuypers, M. M. M.; Lavik, G.; Hallam, S. J.; Wenk, C. B.; Chang, B. X.; Murdock, S. A.; Lehmann, M. F.</p> <p>2012-11-01</p> <p>Little is known about fixed nitrogen (N) transformation and elimination at diffuse <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> where anoxic fluids are mixed with oxygenated crustal seawater prior to discharge. Oceanic N sinks that remove bio-available N ultimately affect chemosynthetic primary productivity in these ecosystems. Using 15N paired isotope techniques, we determined potential rates of fixed N loss pathways (denitrification, anammox) and dissimilatory nitrate reduction to ammonium (DNRA) in sulfidic <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids discharging from the subsurface at several <span class="hlt">sites</span> at Axial Volcano and the Endeavour Segment on the Juan de Fuca Ridge. We also measured physico-chemical parameters (i.e., temperature, pH, nutrients, H2S and N2O concentrations) as well as the biodiversity and abundance of chemolithoautotrophic nitrate-reducing, sulfur-oxidizing ?-proteobacteria (SUP05 cluster) using sequence analysis of amplified small subunit ribosomal RNA (16S rRNA) genes in combination with taxon-specific quantitative polymerase chain reaction (qPCR) assays. Denitrification was the dominant N loss pathway in the subsurface biosphere of the Juan de Fuca Ridge, with rates of up to ~1000 nmol N l-1 day-1. In comparison, anammox rates were always < 5 nmol N l-1 day-1 and below the detection limit at most of the <span class="hlt">sites</span>. DNRA rates were up to ~150 nmol N l-1 day-1. These results suggest that bacterial denitrification out-competes anammox in sulfidic <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> waters. Taxon-specific qPCR revealed that ?-proteobacteria of the SUP05 cluster sometimes dominated the microbial community (SUP05/total bacteria up to 38%). Significant correlations were found between fixed N loss (i.e., denitrification, anammox) rates and in situ nitrate and dissolved inorganic nitrogen (DIN) deficits in the fluids, indicating that DIN availability may ultimately regulate N loss in the subsurface. Based on our rate measurements, and on published data on <span class="hlt">hydrothermal</span> fluid fluxes and residence times, we estimated that up to ~10 Tg N yr-1 could globally be removed in the subsurface biosphere of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> systems, thus, representing a small fraction of the total marine N loss (~275 to > 400 Tg N yr-1).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFMGP23A0166L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFMGP23A0166L"><span id="translatedtitle">Magnetic and Electron Microscopic Investigation on Rock Samples from the PACMANUS <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Field in Papua New Guinea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, S.; Doh, S.; Kim, Y.</p> <p>2004-12-01</p> <p>The PACMANUS <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field in the Eastern Manus back-arc basin, Papua New Guinea, is considered as a modern-day analog of massive volcanogenic sulfide deposits within felsic volcanic sequence. This active <span class="hlt">vent</span> field was drilling in November-December 2003 by Ocean Drilling Program Leg 193. The recovery was generally low with less than 15% due to fragility of rocks. Paleomagnetic measurements and scanning electron microscope observations were performed on samples from three major <span class="hlt">sites</span> (<span class="hlt">Sites</span> 1188, 1189 and 1191). <span class="hlt">Site</span> 1188, a low-temperature diffused <span class="hlt">venting</span> region, was drilled to 370 mbsf. <span class="hlt">Site</span> 1189, a black smoker region, was drilled to a depth of 200 mbsf using RCB. The recovered rock samples have inclination close to the present-day Earth field (-7° ), but those near the seafloor have much steeper inclination of up to -25° . The upper 35 m of the <span class="hlt">sites</span> consists of fresh to moderately altered dacite-rhyodacite, which exhibits moderately high natural remanent magnetization (< 6 A/m). The region below this extrusive layer largely comprises of pervasively altered rocks with little evidence of sulfide deposit and as a whole exhibits a low magnetization intensity. However, two intervals with extremely high remanent magnetization were discovered below the upper extrusive layer at <span class="hlt">Site</span> 1188 (135-211 mbsf and 280-370 mbsf) and one interval at <span class="hlt">Site</span> 1189 (137-190 mbsf). In particular, the samples between 135-211-mbsf interval at <span class="hlt">Site</span> 1188 have extremely high remanence with intensities ranging up to 300-500 A/m. Although pockets of magnetite are not uncommon in the ancient <span class="hlt">hydrothermal</span> ore bodies, they have seldom been documented in modern-day system, and little is known about the physical and chemical condition that allows the magnetite to form in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems. Two possibilities of magnetite formation are explored: one that these magnetites precipitated from magnetite-rich fluid as it cooled from above the Curie temperature (TRM) and the other that magnetization was acquired by the growth of magnetite grains below the Curie temperature (CRM).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.1522K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.1522K"><span id="translatedtitle">Magnetic characteristics of possible <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in TA 25 and TA26 seamounts, the Lau Basin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Chang Hwan; Choi, Soon Young; Park, Chan Hong</p> <p>2014-05-01</p> <p>The deep sea three component magnetic survey was conducted in the western (<span class="hlt">site</span> A) and eastern (<span class="hlt">site</span> B) slopes of the caldera of TA25 seamount and the summit area of TA26 seamount, the Lau Basin, the southwestern Pacific, at Jan. 2012, using German R/V SONNE and ROV (Remotely Operated Vehicle) of ROPOS Co. The magnetic survey lines were the 29 N-S lines (TA25-East : 12 lines, TA25-West : 11 lines, TA26 : 6 lines) with about 100 m spacing and about 50 m above seafloor. For the magnetic survey, the magnetometer sensor was attached with the line frame of ROV and the data logger and motion sensor in ROV. A motion sensor (Octans) provided us the data of pitch, roll, yaw for the correction of the magnetic data to the motion of ROV. The data of the magnetometer and motion sensors and the USBL(Ultra Short Base Line) data of the position of ROV were recorded on a notebook through the optical cable of ROV. <span class="hlt">Hydrothermal</span> fluids over Curie temperature can quickly alter or replace the iron-rich magnetic minerals, reducing the magnetic remanence of the crustal rocks, in some cases to near 0 A/m magnetization. The magnetic anomaly map of TA25 <span class="hlt">site</span> A shows high anomalies in the central part and low anomalies in the northern part, ranging from about -500 to 500 nT. The magnetization map, calculated by the inversion of the bathymetry and the magnetic anomaly, represents low anomalous zones over the south-western part and the northern part of the area. The magnetic anomaly map of TA25 <span class="hlt">site</span> B displays high anomalies in the southeastern part and low anomalies in the central and eastern parts, ranging from about -700 to 800 nT. The low magnetization zones occur over the western part and central part of the area. The high magnetic anomalies of the survey area of TA26 are located in the north and northeastern parts and low anomalies in the southeastern part, with the magnetic anomaly range from about -2000 to 1600 nT. The magnetization map shows east-west trend low anomalous zones in the area. The low anomalous magnetization zones of the survey areas usually appear in groups. Some of these low magnetization zones are well matched with the chimney <span class="hlt">sites</span> or <span class="hlt">hydrothermal</span> altered areas, based on the previous results of video or rock sampling. The low magnetization zones are likely to be the possible <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4124060','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4124060"><span id="translatedtitle">Morphotypes of virus-like particles in two <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields on the East Scotia Ridge, Antarctica</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Millard, Andrew D; Hands-Portman, Ian; Zwirglmaier, Katrin</p> <p>2014-01-01</p> <p>Viruses from extreme environments are still largely unexplored and may harbor unseen genetic potential. Here, we present a first glance at the morphological diversity of virus like particles (VLPs) from an environment that is extreme in more than one respect: two recently discovered <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields on the East Scotia Ridge in the Southern Ocean near Antarctica. They are the southernmost <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> found to date and have been shown to present a new biogeographic province, containing several new macrofaunal species and associated microbial organisms. Transmission electron microscopy revealed a range of tailed and untailed VLPs of various morphologies as well as an unusual long rod-shaped VLP with three long filaments. Based on its distant similarity with several known archaeal viruses, we hypothesize that this presents a new viral morphology that most likely infects an archaeon. Notably absent in the samples we analyzed were lemon- or spindle-shaped VLPs that have previously been described in other <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> settings. PMID:25105058</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060010264&hterms=Hydrothermal+vents&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2528Hydrothermal%2Bvents%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060010264&hterms=Hydrothermal+vents&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3D%2528Hydrothermal%2Bvents%2529"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Sampler: Does Life Exist in High Temperature Environments?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rivadeneyra, Cesar R.</p> <p>2005-01-01</p> <p>The main purpose of this research is to search for the existence of biomass under extreme temperature and pressure conditions to determine the upper bounds of environments on which life can exist. <span class="hlt">Vents</span> are, simply put, underwater volcano openings located at the bottom of the sea. The conditions at these locations are considerably extreme with pressures of up to 10,000 psi, and enormous temperature gradients. The temperature of the water near these <span class="hlt">vents</span> is around 400 C, while that of the surrounding water is about 3 C. The extremity of these conditions makes it hard to estimate the existence of life in those environments. I n order to find whether such existence happens, we need to search for biomass inside these <span class="hlt">vents</span>. The <span class="hlt">vent</span> sampler is a device that has the purpose of safely and accurately collecting this biomass for examination. This sampler is constituted of a Series of filters of the order of 100-0.2 microns in size. Since this is a 3-year project, it has not concluded yet; however, during the time I contributed to this project, I worked with the mechanical design of this sampler device including the selection, assembly, and testing of the various subsystems and the design and construction of the electronics enclosure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS23D1238F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS23D1238F"><span id="translatedtitle">Trace Metal and Sulfur Dynamics in the First Meter of Buoyant <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Plumes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Findlay, A.; Gartman, A.; Shaw, T. J.; Luther, G. W., III</p> <p>2014-12-01</p> <p>The speciation and reactivity of metals and metal sulfides within the buoyant plume is critical to determining the ultimate fate of metals emitted from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. The concentration, size fractionation, and partitioning of trace metals (Fe, Mn, Cu, Co, Zn, Cd, Pb) were determined within the first meter of the rising plume at three <span class="hlt">vent</span> fields (TAG, Snakepit, and Rainbow) along the Mid-Atlantic Ridge. At Rainbow, total Fe concentrations exceed total sulfide concentrations by an order of magnitude, whereas at the other two <span class="hlt">sites</span>, total Fe and total sulfide concentrations are nearly equal. At all three <span class="hlt">sites</span>, Mn and Fe are primarily in the filtered (< 0.2 ?m) fraction and Cu, Co, Zn, Cd, and Pb are mainly in the unfiltered fraction. At TAG and Snakepit, unfiltered copper is correlated with unfiltered cobalt, and unfiltered zinc is correlated with unfiltered cadmium and lead. At Rainbow, unfiltered zinc, cadmium and lead are correlated, but unfiltered copper and cobalt are not, indicating precipitation dynamics at Rainbow are different than those at TAG and Snakepit due to bulk geochemical differences, including a higher iron to sulfide ratio. A sequential HCl/HNO3 leaching method was used to distinguish metals present in pyrite and chalcopyrite in both unfiltered and filtered samples. Significant portions of unfiltered Cu and Co were extracted in HNO3, whereas unfiltered Zn, Cd, and Pb were extracted in HCl. Up to 95 % of filtered Cu, Co, and Zn, up to 80% Cd, and up to 60 % Pb are only extractable in HNO3, indicating that a significant portion of metals < 0.2 ?m are incorporated into a recalcitrant fraction such as nanoparticulate pyrite or chalcopyrite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3282477','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3282477"><span id="translatedtitle">Distribution, Abundance, and Diversity Patterns of the Thermoacidophilic “Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Euryarchaeota 2”</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Flores, Gilberto E.; Wagner, Isaac D.; Liu, Yitai; Reysenbach, Anna-Louise</p> <p>2011-01-01</p> <p>Cultivation-independent studies have shown that taxa belonging to the “deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> euryarchaeota 2” (DHVE2) lineage are widespread at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. While this lineage appears to be a common and important member of the microbial community at <span class="hlt">vent</span> environments, relatively little is known about their overall distribution and phylogenetic diversity. In this study, we examined the distribution, relative abundance, co-occurrence patterns, and phylogenetic diversity of cultivable thermoacidophilic DHVE2 in deposits from globally distributed <span class="hlt">vent</span> fields. Results of quantitative polymerase chain reaction assays with primers specific for the DHVE2 and Archaea demonstrate the ubiquity of the DHVE2 at deep-sea <span class="hlt">vents</span> and suggest that they are significant members of the archaeal communities of established <span class="hlt">vent</span> deposit communities. Local similarity analysis of pyrosequencing data revealed that the distribution of the DHVE2 was positively correlated with 10 other Euryarchaeota phylotypes and negatively correlated with mostly Crenarchaeota phylotypes. Targeted cultivation efforts resulted in the isolation of 12 axenic strains from six different <span class="hlt">vent</span> fields, expanding the cultivable diversity of this lineage to <span class="hlt">vents</span> along the East Pacific Rise and Mid-Atlantic Ridge. Eleven of these isolates shared greater than 97% 16S rRNA gene sequence similarity with one another and the only described isolate of the DHVE2, Aciduliprofundum boonei T469T. Sequencing and phylogenetic analysis of five protein-coding loci, atpA, EF-2, radA, rpoB, and secY, revealed clustering of isolates according to geographic region of isolation. Overall, this study increases our understanding of the distribution, abundance, and phylogenetic diversity of the DHVE2. PMID:22363325</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4145251','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4145251"><span id="translatedtitle">Sulfur and oxygen isotope insights into sulfur cycling in shallow-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, Milos, Greece</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2014-01-01</p> <p>Shallow-sea (5 m depth) <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> off Milos Island provides an ideal opportunity to target transitions between igneous abiogenic sulfide inputs and biogenic sulfide production during microbial sulfate reduction. Seafloor <span class="hlt">vent</span> features include large (>1 m2) white patches containing <span class="hlt">hydrothermal</span> minerals (elemental sulfur and orange/yellow patches of arsenic-sulfides) and cells of sulfur oxidizing and reducing microorganisms. Sulfide-sensitive film deployed in the <span class="hlt">vent</span> and non-<span class="hlt">vent</span> sediments captured strong geochemical spatial patterns that varied from advective to diffusive sulfide transport from the subsurface. Despite clear visual evidence for the close association of <span class="hlt">vent</span> organisms and <span class="hlt">hydrothermalism</span>, the sulfur and oxygen isotope composition of pore fluids did not permit delineation of a biotic signal separate from an abiotic signal. Hydrogen sulfide (H2S) in the free gas had uniform ?34S values (2.5?±?0.28‰, n?=?4) that were nearly identical to pore water H2S (2.7?±?0.36‰, n?=?21). In pore water sulfate, there were no paired increases in ?34SSO4 and ?18OSO4 as expected of microbial sulfate reduction. Instead, pore water ?34SSO4 values decreased (from approximately 21‰ to 17‰) as temperature increased (up to 97.4°C) across each <span class="hlt">hydrothermal</span> feature. We interpret the inverse relationship between temperature and ?34SSO4 as a mixing process between oxic seawater and 34S-depleted <span class="hlt">hydrothermal</span> inputs that are oxidized during seawater entrainment. An isotope mass balance model suggests secondary sulfate from sulfide oxidation provides at least 15% of the bulk sulfate pool. Coincident with this trend in ?34SSO4, the oxygen isotope composition of sulfate tended to be 18O-enriched in low pH (<5), high temperature (>75°C) pore waters. The shift toward high ?18OSO4 is consistent with equilibrium isotope exchange under acidic and high temperature conditions. The source of H2S contained in <span class="hlt">hydrothermal</span> fluids could not be determined with the present dataset; however, the end-member ?34S value of H2S discharged to the seafloor is consistent with equilibrium isotope exchange with subsurface anhydrite veins at a temperature of ~300°C. Any biological sulfur cycling within these <span class="hlt">hydrothermal</span> systems is masked by abiotic chemical reactions driven by mixing between low-sulfate, H2S-rich <span class="hlt">hydrothermal</span> fluids and oxic, sulfate-rich seawater. PMID:25183951</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3522073','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3522073"><span id="translatedtitle">Widespread Occurrence of Two Carbon Fixation Pathways in Tubeworm Endosymbionts: Lessons from <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Associated Tubeworms from the Mediterranean Sea</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Thiel, Vera; Hügler, Michael; Blümel, Martina; Baumann, Heike I.; Gärtner, Andrea; Schmaljohann, Rolf; Strauss, Harald; Garbe-Schönberg, Dieter; Petersen, Sven; Cowart, Dominique A.; Fisher, Charles R.; Imhoff, Johannes F.</p> <p>2012-01-01</p> <p>Vestimentiferan tubeworms (siboglinid polychetes) of the genus Lamellibrachia are common members of cold seep faunal communities and have also been found at sedimented <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> in the Pacific. As they lack a digestive system, they are nourished by chemoautotrophic bacterial endosymbionts growing in a specialized tissue called the trophosome. Here we present the results of investigations of tubeworms and endosymbionts from a shallow <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field in the Western Mediterranean Sea. The tubeworms, which are the first reported <span class="hlt">vent</span>-associated tubeworms outside the Pacific, are identified as Lamellibrachia anaximandri using mitochondrial ribosomal and cytochrome oxidase I (COI) gene sequences. They harbor a single gammaproteobacterial endosymbiont. Carbon isotopic data, as well as the analysis of genes involved in carbon and sulfur metabolism indicate a sulfide-oxidizing chemoautotrophic endosymbiont. The detection of a hydrogenase gene fragment suggests the potential for hydrogen oxidation as alternative energy source. Surprisingly, the endosymbiont harbors genes for two different carbon fixation pathways, the Calvin-Benson-Bassham (CBB) cycle as well as the reductive tricarboxylic acid (rTCA) cycle, as has been reported for the endosymbiont of the <span class="hlt">vent</span> tubeworm Riftia pachyptila. In addition to RubisCO genes we detected ATP citrate lyase (ACL – the key enzyme of the rTCA cycle) type II gene sequences using newly designed primer sets. Comparative investigations with additional tubeworm species (Lamellibrachia luymesi, Lamellibrachia sp. 1, Lamellibrachia sp. 2, Escarpia laminata, Seepiophila jonesi) from multiple cold seep <span class="hlt">sites</span> in the Gulf of Mexico revealed the presence of acl genes in these species as well. Thus, our study suggests that the presence of two different carbon fixation pathways, the CBB cycle and the rTCA cycle, is not restricted to the Riftia endosymbiont, but rather might be common in vestimentiferan tubeworm endosymbionts, regardless of the habitat. PMID:23248622</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5435606','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5435606"><span id="translatedtitle">Geologic form and setting of a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field at latitude 10/sup 0/56'N, East Pacific Rise: a detailed study using Angus and Alvin</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>McConachy, T.F.; Ballard, R.D.; Mottl, M.J.; Von Herzen, R.P.</p> <p>1986-04-01</p> <p>A <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field, here called the Feather Duster <span class="hlt">site</span>, occurs on the eastern marginal high near the edge of a narrow (95-m) and shallow (15-20-m) axial graben, within an area dominated by sheet flows and collapse features. The sheet flows are intermediate in relative age between younger fluid-flow lavas on the floor of the axial graben and older pillow (constructional) lavas on the marginal highs. <span class="hlt">Hydrothermal</span> activity occurs in two zones within a 65 by 45 m area. The main zone is located where a fissure system and sulfide-sulfate chimneys <span class="hlt">vent</span> warm (9-47/sup 0/C) and hot (347/sup 0/C) <span class="hlt">hydrothermal</span> fluids. Here, two mounds of massive sulfide totaling about 200 t are forming. One occurs at the base of a 3-m-high scarp which is the wall of a drained lava lake; the other is perched on top of the scarp. 19 references, 4 figures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4184897','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4184897"><span id="translatedtitle">Evolutionary Strategies of Viruses, Bacteria and Archaea in <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Ecosystems Revealed through Metagenomics</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Anderson, Rika E.; Sogin, Mitchell L.; Baross, John A.</p> <p>2014-01-01</p> <p>The deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> habitat hosts a diverse community of archaea and bacteria that withstand extreme fluctuations in environmental conditions. Abundant viruses in these systems, a high proportion of which are lysogenic, must also withstand these environmental extremes. Here, we explore the evolutionary strategies of both microorganisms and viruses in <span class="hlt">hydrothermal</span> systems through comparative analysis of a cellular and viral metagenome, collected by size fractionation of high temperature fluids from a diffuse flow <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>. We detected a high enrichment of mobile elements and proviruses in the cellular fraction relative to microorganisms in other environments. We observed a relatively high abundance of genes related to energy metabolism as well as cofactors and vitamins in the viral fraction compared to the cellular fraction, which suggest encoding of auxiliary metabolic genes on viral genomes. Moreover, the observation of stronger purifying selection in the viral versus cellular gene pool suggests viral strategies that promote prolonged host integration. Our results demonstrate that there is great potential for <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> viruses to integrate into hosts, facilitate horizontal gene transfer, and express or transfer genes that manipulate the hosts’ functional capabilities. PMID:25279954</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005DSRI...52..837S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005DSRI...52..837S"><span id="translatedtitle">Selective predation by the zoarcid fish Thermarces cerberus at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sancho, G.; Fisher, C. R.; Mills, S.; Micheli, F.; Johnson, G. A.; Lenihan, H. S.; Peterson, C. H.; Mullineaux, L. S.</p> <p>2005-05-01</p> <p>This study investigates predation by the <span class="hlt">vent</span> zoarcid fish Thermarces cerberus through gastrointestinal analyses of 27 specimens collected with the submersible ALVIN at <span class="hlt">vents</span> at 9°50'N on the East Pacific Rise. T. cerberus fed most frequently on gastropod mollusks (mainly Lepetodrilus elevatus) and amphipod crustaceans (mainly Ventiella sulfuris). Species found occasionally in high abundance included the swarming amphipod Halice hesmonectes and the snail Cyathermia naticoides. Other items also found in gastrointestinal tracts, but in very low numbers, included polychaete worms, crustaceans and unidentified tissue clumps. The comparison between the size distribution of L. elevatus limpets ingested by T. cerberus and those found attached to vestimentiferan tubes suggest that the fish may selectively prey on large limpets. If the selective removal of large Lepetodrilus spp. limpets by T. cerberus does occur, then it would have potential community-level consequences at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, since these mobile gastropods appear to inhibit the settlement of sessile <span class="hlt">vent</span> species, including tube-building worms. Our results suggest possible direct and indirect effects of T. cerberus on benthic community structure at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the East Pacific Rise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3568577','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3568577"><span id="translatedtitle">Detection of Putatively Thermophilic Anaerobic Methanotrophs in Diffuse <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Fluids</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Huber, Julie A.; Chernyh, Nikolay A.; Bonch-Osmolovskaya, Elizaveta A.; Lebedinsky, Alexander V.</p> <p>2013-01-01</p> <p>The anaerobic oxidation of methane (AOM) is carried out by a globally distributed group of uncultivated Euryarchaeota, the anaerobic methanotrophic arachaea (ANME). In this work, we used G+C analysis of 16S rRNA genes to identify a putatively thermophilic ANME group and applied newly designed primers to study its distribution in low-temperature diffuse <span class="hlt">vent</span> fluids from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. We found that the G+C content of the 16S rRNA genes (PGC) is significantly higher in the ANME-1GBa group than in other ANME groups. Based on the positive correlation between the PGC and optimal growth temperatures (Topt) of archaea, we hypothesize that the ANME-1GBa group is adapted to thrive at high temperatures. We designed specific 16S rRNA gene-targeted primers for the ANME-1 cluster to detect all phylogenetic groups within this cluster, including the deeply branching ANME-1GBa group. The primers were successfully tested both in silico and in experiments with sediment samples where ANME-1 phylotypes had previously been detected. The primers were further used to screen for the ANME-1 microorganisms in diffuse <span class="hlt">vent</span> fluid samples from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the Pacific Ocean, and sequences belonging to the ANME-1 cluster were detected in four individual <span class="hlt">vents</span>. Phylotypes belonging to the ANME-1GBa group dominated in clone libraries from three of these <span class="hlt">vents</span>. Our findings provide evidence of existence of a putatively extremely thermophilic group of methanotrophic archaea that occur in geographically and geologically distinct marine <span class="hlt">hydrothermal</span> habitats. PMID:23183981</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMGP11A..07F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMGP11A..07F"><span id="translatedtitle">Absolute Magnetization Distribution on Back-arc Spreading Axis Hosting <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span>; Insight from Shinkai 6500 Magnetic Survey</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fujii, M.; Okino, K.; Honsho, C.; Mochizuki, N.; Szitkar, F.; Dyment, J.</p> <p>2013-12-01</p> <p>Near-bottom magnetic profiling using submersible, deep-tow, Remotely Operated Vehicle (ROV) and Autonomous Underwater Vehicle (AUV) make possible to conduct high-resolution surveys and depict detailed magnetic features reflecting, for instance, the presence of fresh lavas or <span class="hlt">hydrothermal</span> alteration, or geomagnetic paleo-intensity variations. We conducted near-bottom three component magnetic measurements onboard submersible Shinkai 6500 in the Southern Mariana Trough, where five active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields (Snail, Yamanaka, Archean, Pica, and Urashima <span class="hlt">sites</span>) have been found in both on- and off-axis areas of the active back-arc spreading center, to detect signals from <span class="hlt">hydrothermally</span> altered rock and to distinguish old and new submarine lava flows. Fourteen dives were carried out at an altitude of 1-40 m during the R/V Yokosuka YK10-10 and YK10-11 cruises in 2010. We carefully corrected the effect of the induced and permanent magnetizations of the submersible by applying the correction method for the shipboard three-component magnetometer measurement modified for deep-sea measurement, and subtracted the IGRF values from the corrected data to obtain geomagnetic vector anomalies along the dive tracks. We then calculated the synthetic magnetic vector field produced by seafloor, assumed to be uniformly magnetized, using three dimensional forward modeling. Finally, values of the absolute magnetizations were estimated by using a linear transfer function in the Fourier domain from the observed and synthetic magnetic anomalies. The distribution of estimated absolute magnetization generally shows low values around the five <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span>. This result is consistent with the equivalent magnetization distribution obtained from previous AUV survey data. The areas of low magnetization are also consistent with <span class="hlt">hydrothermal</span> deposits identified in video records. These results suggest that low magnetic signals are due to <span class="hlt">hydrothermal</span> alteration zones where host rocks are demagnetized by <span class="hlt">hydrothermal</span> circulation. The low magnetization zones around the off-axis <span class="hlt">vent</span> <span class="hlt">sites</span> are about ten times wider than those surrounding the on-axis <span class="hlt">sites</span>, possibly reflecting the longer duration of <span class="hlt">hydrothermal</span> circulation at these <span class="hlt">sites</span>. Another interesting result is that the absolute magnetization shows extremely high intensities (>80 A/m) at the neo volcanic zones (NVZ) and relatively low intensities (<10 A/m) two to five kilometers away from the NVZ. These variations are quite consistent with those of the Natural Remanent Magnetization measured on basalt samples, suggesting that the low-temperature oxidation of host rock due to the reaction with seawater has completed within a few kilometers distance from the spreading axis. We conclude that the magnetization of the uppermost oceanic crust decreases with age due to the combination of the both <span class="hlt">hydrothermal</span> rapid alteration and the low-temperature gradual alteration processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dspace.mit.edu/handle/1721.1/54566','EPRINT'); return false;" href="http://dspace.mit.edu/handle/1721.1/54566"><span id="translatedtitle">Biotic and abiotic interactions of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>-endemic fish on the East Pacific Rise</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Buckman, Kate Lynn</p> <p>2009-01-01</p> <p>A study of the ecology of fish endemic to <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the East Pacific Rise was undertaken utilizing a variety of techniques, focusing on the bythitid Thermichthys hollisi. Stable isotope and gut content analyses ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4206443','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4206443"><span id="translatedtitle">Phenotypic Variation and Fitness in a Metapopulation of Tubeworms (Ridgeia piscesae Jones) at <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tunnicliffe, Verena; St. Germain, Candice; Hilário, Ana</p> <p>2014-01-01</p> <p>We examine the nature of variation in a hot <span class="hlt">vent</span> tubeworm, Ridgeia piscesae, to determine how phenotypes are maintained and how reproductive potential is dictated by habitat. This foundation species at northeast Pacific <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> occupies a wide habitat range in a highly heterogeneous environment. Where fluids supply high levels of dissolved sulphide for symbionts, the worm grows rapidly in a “short-fat” phenotype characterized by lush gill plumes; when plumes are healthy, sperm package capture is higher. This form can mature within months and has a high fecundity with continuous gamete output and a lifespan of about three years in unstable conditions. Other phenotypes occupy low fluid flux habitats that are more stable and individuals grow very slowly; however, they have low reproductive readiness that is hampered further by small, predator cropped branchiae, thus reducing fertilization and metabolite uptake. Although only the largest worms were measured, only 17% of low flux worms were reproductively competent compared to 91% of high flux worms. A model of reproductive readiness illustrates that tube diameter is a good predictor of reproductive output and that few low flux worms reached critical reproductive size. We postulate that most of the propagules for the <span class="hlt">vent</span> fields originate from the larger tubeworms that live in small, unstable habitat patches. The large expanses of worms in more stable low flux habitat sustain a small, but long-term, reproductive output. Phenotypic variation is an adaptation that fosters both morphological and physiological responses to differences in chemical milieu and predator pressure. This foundation species forms a metapopulation with variable growth characteristics in a heterogeneous environment where a strategy of phenotypic variation bestows an advantage over specialization. PMID:25337895</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16329980','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16329980"><span id="translatedtitle">Variability in microbial community and <span class="hlt">venting</span> chemistry in a sediment-hosted backarc <span class="hlt">hydrothermal</span> system: Impacts of subseafloor phase-separation.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nakagawa, Satoshi; Takai, Ken; Inagaki, Fumio; Chiba, Hitoshi; Ishibashi, Jun-ichiro; Kataoka, Satoshi; Hirayama, Hisako; Nunoura, Takuro; Horikoshi, Koki; Sako, Yoshihiko</p> <p>2005-09-01</p> <p>Phase-separation and -segregation (boiling/distillation of subseafloor <span class="hlt">hydrothermal</span> fluids) represent the primary mechanisms causing intra-field variations in <span class="hlt">vent</span> fluid compositions. To determine whether this geochemical process affects the formation of microbial communities, we examined the microbial communities at three different <span class="hlt">vent</span> <span class="hlt">sites</span> located within a few tens meters of one another. In addition to chimney structures, colonization devices capturing subseafloor communities entrained by the <span class="hlt">vent</span> fluids were studied, using culture-dependent and -independent methods. Microbiological analyses demonstrated the occurrence of distinctive microbial communities in each of the <span class="hlt">hydrothermal</span> niches. Within a chimney structure, there was a transition from a mixed community of mesophiles and thermophiles in the exterior parts to thermophiles in the interior. Beside the transition within a chimney structure, intra-field variations in microbial communities in <span class="hlt">vent</span> fluids were apparent. Geochemical analysis demonstrated that different <span class="hlt">vent</span> fluids have distinctive end-member compositions as a consequence of subseafloor phase-separation and -segregation, which were designated gas-depleted, normal and gas-enriched fluids. In comparison to gas-depleted and normal fluids, gas-enriched fluids harbored more abundant chemolithoautotrophs with gaseous component-dependent energy metabolism, such as hydrogenotrophic methanogenesis. Subseafloor phase-separation and -segregation may play a key role in supplying energy and carbon sources to <span class="hlt">vent</span>-associated chemolithoautotrophs and subvent microbial communities. PMID:16329980</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.C41B0329S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.C41B0329S"><span id="translatedtitle">Autonomous Underwater Vehicle(AUV) and Towed Vehicle Technologies for Under-Ice <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Studies at the Gakkel Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Singh, H.; Akin, D.; Reves-Sohn, R.; Humphris, S.; Shank, T.; Edmonds, H.</p> <p>2006-12-01</p> <p>The extreme polar environment presents a unique challenge to the use of the otherwise mature oceanographic technologies associated with Autonomous Underwater Vehicles (AUVs), Remotely Operated Vehicles (ROVs) and towed vehicles. For deep water mapping and sampling applications, ice cover in the arctic is a formidable obstacle. In pursuing our goals to locate, map and sample <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the Gakkel Ridge, we have built and plan to deploy two AUVs named JAGUAR and PUMA and a towed sampling sled with hydraulically actuated sampling chambers. Our methodologies for working with AUVs in the Arctic differ significantly from standard blue-water operations. Specifically, we have focused on, deploying and calibrating acoustic transponders with the limited mobility imposed by multi-year ice; a far more robust system architecture for dealing with component failures underwater; an autonomous manipulation system on the AUV for capturing sessile biological organisms and geological samples; and a low bandwidth acoustic tether for vehicle status, navigation and mission redirection. Our sampling sled was designed with the premise that the limited mobility associated with working in ice will at best provide us with a few, short opportunities to image and sample on a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">site</span>. To this end our sled is equipped with a suite of imaging and chemical sensors as well as devices for quickly obtaining multiple samples of both sessile and motile biological organisms. We plan to deploy these new technologies during the International Polar Year in 2007 as part of a collaborative international effort to characterize the biological and geological characteristics of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> on the ultra-slow spreading Gakkel Ridge in the eastern Arctic basin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.V72A1294K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.V72A1294K"><span id="translatedtitle">A Search for Biomarkers in Microbial Origin in <span class="hlt">Hydrothermal</span> Fluids From <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> at the Suiyo Seamount</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kitajima, F.; Yamanaka, T.</p> <p>2002-12-01</p> <p>We tried to search biomarkers in microbial origin in hot fluids from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Hot water samples were collected from three natural <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> (Tmax. = 310, 221, and 48°\\ C) and a drilled core (APSK05, Tmax. = 21°\\ C) located in a seafloor <span class="hlt">hydrothermal</span> system developed on atop of the Suiyo Seamount, Izu-Ogasawara island-arc, western Pasific, using a ROV Hakuyo 2000, during the Shinsei-Maru cruise in July-August 2001 and the Shinryu-Maru cruise in August 2002. Hot water passed through a ODS disk (Empore Extraction Disk 90mm? ) with a pre-filter (pore size 1?m), and dissolved organic matter was adsorbed on the ODS disk. The adsorbed organic matter was eluted with toluene using Soxhlet extractor for 12h. After the eluents were concentrated, they were analyzed by GCMS. Some hydrocarbons that show basepeak at M/Z = 69 were found in hot water from APSK05, and these compounds may indicate the existence of alkylcyclopentanes that are characteristic for some thermoacidophilic bacteria, and that have been reported from the seafloor deposits of the Suiyo Seamount.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.B14B..01C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.B14B..01C"><span id="translatedtitle">Fe-oxidizing microbes are <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystem engineers at the Loihi Seamount (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chan, C. S.; McAllister, S.; Leavitt, A.; Emerson, D.; Moyer, C. L.; Glazer, B. T.</p> <p>2013-12-01</p> <p>Microaerophilic Fe-oxidizing microorganisms (FeOM) colonize gradients of Fe(II) and oxygen, taking advantage of the available chemical energy. Vast communities of FeOM proliferate at deep sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, forming mineralized mats that range from centimeters to meters thick. Because these mats structure the environment for both FeOM and the entire microbial community, the Fe-oxidizers are acting as ecosystem engineers. What organisms are responsible for initiating these mats, and how does the physical structure and community composition develop as the mats mature? By connecting structure, function, and ecology, we can better interpret modern mat structures, as well as ancient fossilized mats. We have been studying Fe microbial mats at Loihi Seamount in Hawaii, a long-term study <span class="hlt">site</span> that has become a model for Fe oxidation in marine <span class="hlt">hydrothermal</span> systems. Recent improvements in ROV imaging systems allow us to see a great range of mat textures and colors, which may represent diverse habitats and/or different stages of mat development. With improved imaging and sampling techniques, we have been able to obtain discrete, intact samples of these delicate microbial mats. Previous bulk sampling methods showed that mats consist of a mixture of Fe-mineralized morphologies. Our analyses of intact mats show that mats are initiated by one type of structure-former (either a stalk-former like Mariprofundus ferrooxydans or a Zetaproteobacterial sheath-former). These microbes may be the vanguard organisms that stabilize chemical gradients in this dynamic environment, allowing colonization by other organisms (evidenced by branching tubes, fibrillar nests, and other morphologies). We will show evidence of the composition and development of these mats, and discuss parallels between these marine Fe mats and their freshwater counterparts, supporting the idea that FeOM engineer environments favorable for growth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS51D1906W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS51D1906W"><span id="translatedtitle">Near-bottom water column anomalies associated with active <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> at Aeolian arc volcanoes, Tyrrhenian Sea, Italy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Walker, S. L.; Carey, S.; Bell, K. L.; Baker, E. T.; Faure, K.; Rosi, M.; Marani, M.; Nomikou, P.</p> <p>2012-12-01</p> <p><span class="hlt">Hydrothermal</span> deposits such as metalliferous sediments, Fe-Mn crusts, and massive sulfides are common on the submarine volcanoes of the Aeolian arc (Tyrrhenian Sea, Italy), but the extent and style of active <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> is less well known. A systematic water column survey in 2007 found helium isotope ratios indicative of active <span class="hlt">venting</span> at 6 of the 9 submarine volcanoes surveyed plus the Marsili back-arc spreading center (Lupton et al., 2011). Other plume indicators, such as turbidity and temperature anomalies were weak or not detected. In September 2011, we conducted five ROV Hercules dives at Eolo, Enarete, and Palinuro volcanoes during an E/V Nautilus expedition. Additionally, two dives explored the Casoni seamount on the southern flank of Stromboli where a dredge returned apparently warm lava in 2002 (Gamberi, 2006). Four PMEL MAPRs, with temperature, optical backscatter (particles), and oxidation-reduction potential (ORP) sensors, were arrayed along the lowermost 50 m of the Hercules/Argus cable during the dives to assess the relationship between seafloor observations and water column anomalies. Active <span class="hlt">venting</span> was observed at each of the volcanoes visited. Particle anomalies were weak or absent, consistent with the 2007 CTD surveys, but ORP anomalies were common. <span class="hlt">Venting</span> at Eolo volcano was characterized by small, localized patches of yellow-orange bacteria; living tubeworms were observed at one location. ORP anomalies (-1 to -22 mv) were measured at several locations, primarily along the walls of the crescent-shaped collapse area (or possible caldera) east of the Eolo summit. At Enarete volcano, we found <span class="hlt">venting</span> fluids with temperatures up to 5°C above ambient as well as small, fragile iron-oxide chimneys. The most intense ORP anomaly (-140 mv) occurred at a depth of about 495 m on the southeast side of the volcano, with smaller anomalies (-10 to -20 mv) more common as the ROV moved upslope to the summit. At Palinuro volcano, multiple dives located several active <span class="hlt">sites</span> along the 50-km-long summit. The distribution of ORP anomalies seen during these dives correlates quite well with the locations of anomalous helium samples from 2007. An ORP anomaly of -160 mv was located at the west end of Palinuro where <span class="hlt">vent</span> fluids up to 54°C were found. Living tubeworms, bacterial mats of various colors and textures, and small chimneys and globular spires coated with iron oxide having bright-green interiors indicative of the iron-rich <span class="hlt">hydrothermal</span> clay nontronite were found at actively <span class="hlt">venting</span> areas on Palinuro. ORP anomalies were generally only detected in the near-bottom MAPR mounted on Hercules. In a few locations the MAPRs on Argus (10-30 meters above bottom) and 25 meters above Argus registered anomalies not seen by the MAPR on Hercules indicating active <span class="hlt">venting</span> nearby, but not observed along the trackline of the ROV. Only the higher-temperature <span class="hlt">vent</span> <span class="hlt">site</span> at the west end of Palinuro generated a plume that had an appreciable particle anomaly and rise height (seen by the Argus+25m MAPR). No anomalies were measured by the MAPR located 50 meters above Argus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=91466','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=91466"><span id="translatedtitle">Identification and Characterization of a Flagellin Gene from the Endosymbiont of the <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Tubeworm Riftia pachyptila</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Millikan, Deborah S.; Felbeck, Horst; Stein, Jeffrey L.</p> <p>1999-01-01</p> <p>The bacterial endosymbionts of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworm Riftia pachyptila play a key role in providing their host with fixed carbon. Results of prior research suggest that the symbionts are selected from an environmental bacterial population, although a free-living form has been neither cultured from nor identified in the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environment. To begin to assess the free-living potential of the symbiont, we cloned and characterized a flagellin gene from a symbiont fosmid library. The symbiont fliC gene has a high degree of homology with other bacterial flagellin genes in the amino- and carboxy-terminal regions, while the central region was found to be nonconserved. A sequence that was homologous to that of a consensus ?28 RNA polymerase recognition <span class="hlt">site</span> lay upstream of the proposed translational start <span class="hlt">site</span>. The symbiont protein was expressed in Escherichia coli, and flagella were observed by electron microscopy. A 30,000-Mr protein subunit was identified in whole-cell extracts by Western blot analysis. These results provide the first direct evidence of a motile free-living stage of a chemoautotrophic symbiont and support the hypothesis that the symbiont of R. pachyptila is acquired with each new host generation. PMID:10388713</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21856628','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21856628"><span id="translatedtitle">Biogeography revisited with network theory: retracing the history of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> communities.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Moalic, Yann; Desbruyères, Daniel; Duarte, Carlos M; Rozenfeld, Alejandro F; Bachraty, Charleyne; Arnaud-Haond, Sophie</p> <p>2012-01-01</p> <p>Defining biogeographic provinces to understand the history and evolution of communities associated with a given kind of ecosystem is challenging and usually requires a priori assumptions to be made. We applied network theory, a holistic and exploratory method, to the most complete database of faunal distribution available on oceanic <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, environments which support fragmented and unstable ecosystems, to infer the processes driving their worldwide biogeography. Besides the identification of robust provinces, the network topology allowed us to identify preferential pathways that had hitherto been overlooked. These pathways are consistent with the previously proposed hypothesis of a role of plate tectonics in the biogeographical history of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> communities. A possible ancestral position of the Western Pacific is also suggested for the first time. Finally, this work provides an innovative example of the potential of network tools to unravel the biogeographic history of faunal assemblages and to supply comprehensive information for the conservation and management of biodiversity. PMID:21856628</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12187645','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12187645"><span id="translatedtitle">Does sulphide detoxication occur in the gills of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> shrimp, Rimicaris exoculata?</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Compère, Philippe; Martinez, Anne-Sophie; Charmantier-Daures, Mireille; Toullec, Jean-Yves; Goffinet, Gerhard; Gaill, Françoise</p> <p>2002-05-01</p> <p>Ultrastructural observations of the gills of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> shrimp Rimicaris exoculata reveal that the epithelial cells contain numerous mitochondria clustered around unusual organelles (diameter of 0.7 to 2.5 microns) containing membrane stacks. These organelles were termed sulphide-oxidising bodies (SOBs) by structural analogy with organelles observed in the tissues of species adapted to sulphide-rich environments. Moreover, in the gills of R. exoculata, mitochondria display numerous electron-dense granules in their stroma. Such ultrastructural features suggest that sulphide detoxication may probably occur in the gills of R. exoculata. Comparable structures were also described in the gills of other <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> species, as the alvinellid Pompeii worms that, as R. exoculata, are housing ectosymbiotic bacteria. PMID:12187645</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=134447','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=134447"><span id="translatedtitle">Bacterial Group II Introns in a Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Environment†</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Podar, Mircea; Mullineaux, Lauren; Huang, Hon-Ren; Perlman, Philip S.; Sogin, Mitchell L.</p> <p>2002-01-01</p> <p>Group II introns are catalytic RNAs and mobile retrotransposable elements known to be present in the genomes of some nonmarine bacteria and eukaryotic organelles. Here we report the discovery of group II introns in a bacterial mat sample collected from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> near 9°N on the East Pacific Rise. One of the introns was shown to self-splice in vitro. This is the first example of marine bacterial introns from molecular population structure studies of microorganisms that live in the proximity of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. These types of mobile genetic elements may prove useful in improving our understanding of bacterial genome evolution and may serve as valuable markers in comparative studies of bacterial communities. PMID:12450865</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6002664','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6002664"><span id="translatedtitle">Biological communities at the Florida Escarpment resemble <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> taxa</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Paull, C.K.; Hecker, B.; Commeau, R.; Freeman-Lynde, R.P.; Neumann, C.; Corso, W.P.; Golubic, S.; Hook, J.E.; Sikes, E.; Curray, J.</p> <p>1984-11-23</p> <p>Dense biological communities of large epifaunal taxa similar to those found along ridge crest <span class="hlt">vents</span> at the East Pacific Rise were discovered in the abyssal Gulf of Mexico. These assemblages occur on a passive continental margin at the base of the Florida Escarpment, the interface between the relatively impermeable hemipelagic clays of the distal Mississippi Fan and the jointed Cretaceous limestone of Florida Platform. The fauna apparently is nourished by sulfide rich hypersaline waters seeping out at near ambient temperatures onto the sea floor. 16 references, 3 figures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70013515','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70013515"><span id="translatedtitle">Biological communities at the Florida Escarpment resemble <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> taxa</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Paull, C.K.; Hecker, Barbara; Commeau, R.; Freeman-Lynde, R. P.; Neumann, C.; Corso, W.P.; Golubic, S.; Hook, J.E.; Sikes, E.; Curray, J.</p> <p>1984-01-01</p> <p>Dense biological communities of large epifaunal taxa similar to those found along ridge crest <span class="hlt">vents</span> at the East Pacific Rise were discovered in the abyssal Gulf of Mexico. These assemblages occur on a passive continental margin at the base of the Florida Escarpment, the interface between the relatively impermeable hemipelagic clays of the distal Mississippi Fan and the jointed Cretaceous limestone of the Florida Platform. The fauna apparently is nourished by sulfide rich hypersaline waters seeping out at near ambient temperatures onto the sea floor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.B23J..05S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.B23J..05S"><span id="translatedtitle">Metaproteomic Analysis of a Chemosynthetic <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Community Reveals Insights into Key-Metabolic Processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Steen, I.; Stokke, R.; Lanzen, A.; Pedersen, R.; Øvreås, L.; Urich, T.</p> <p>2010-12-01</p> <p>In 2005 researchers at the Centre for Geobiology, University of Bergen, Norway, discovered two active <span class="hlt">vent</span> fields at the southwestern Mohns Ridge in the Norwegian-Greenland Sea. The fields harbours both low-temperature iron deposits and high-temperature white smoker <span class="hlt">vents</span>. Distinct microbial mats were abundantly present and located in close vicinity to the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span>. Characteristics of the mat environment were steep physical and chemical gradients with temperatures ranging from 10°C in the top layer to 90°C at 10 cm bsf and high concentrations of hydrogen sulfide and methane. The work presented here focus on the In situ community activities, and is part of an integrated strategy combining metagenomics, metatranscriptomics and metaproteomics to in-depth characterise these newly discovered <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> communities. Extracted proteins were separated via SDS-PAGE. Peptides extracted after In-gel tryptic digest was injected into an Ultimate 3000 nanoLC system connected to a linear quadropole ion trap-orbitrap (LTQ-Orbitrap XL) mass spectrometer equipped with a nanoelectrospray ion source. A custom database of open reading frames (ORFs) from the combined metatranscriptome and metagenome datasets was implemented and searched against using Mascot 2.2; the IRMa tool box [1] was used in peptide validation. Validated ORFs were subjected to a Blastp search against Refseq with an E-value cut-off of 0.001. A total of 1097 proteins with ? 2 peptides were identified of which 921 gave a hit against Refseq, containing 519 unique proteins. Key enzymes of the sulfur oxidation pathway (sox) were found, which were taxonomically affiliated to Epsilonproteobacteria. In addition, this group actively expressed hydrogenases and membrane proteins involved in aerobic and anaerobic respiratory chains. Enzymes of dissimilatory sulfate-reduction (APS-reductase, AprAB and DsrA2) were found with closest hit to members of the Deltaproteobacteria. These findings indicate an internal sulfur cycle within the community. The community contained expressed enzymes of a variety of carbon metabolism pathways. Key enzymes of the reverse TCA cycle for fixation of CO2 and the Wood-Ljungdahl pathway for oxidation of acetyl-CoA and / or the fixation of CO2 were found. Key enzymes of aerobic and anaerobic methane-oxidation pathways were identified as well, namely particulate methane monooxygenase and methyl-Coenzyme M reductase. Various house-keeping gene-products, like cold- and heat shock proteins as well as ribosomal proteins and ATP synthases were identified. This approach has a future potential of broadening our understanding of environmental complexity and regulation in response to geochemical constraints. [1] Dupierris, V., Masselon, C., Court, M., Kieffer-Jaquinod, S., and Bruley, C. (2009) A toolbox for validation of mass spectrometry peptides identification and generation of database: IRMa. Bioinformatics 25, 1980-1981.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.V41B2081T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.V41B2081T"><span id="translatedtitle">First Active <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Fields Discovered at the Equatorial Southern East Pacific Rise</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tao, C.; Lin, J.; Wu, G.; German, C. R.; Yoerger, D. R.; Chen, Y. J.; Guo, S.; Zeng, Z.; Han, X.; Zhou, N.; Li, J.; Xia, S.; Wang, H.; Ding, T.; Gao, S.; Qian, X.; Cui, R.; Zhou, J.; Ye, D.; Zhang8, Y.; Zhang, D.; Li, L.; Zhang, X.; Li, Y.; Wu, X.; Li, S.; He, Y.; Huang, W.; Wang, Y.; Wang, T.; Li, X.; Wang, K.; Gai, Y.; Science Party, D.; Baker, E. T.; Nakamura14, K.</p> <p>2008-12-01</p> <p>The third leg of the 2008 Chinese DY115-20 expedition on board R/V Dayangyihao has successfully discovered, for the first time, active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields on the fast-spreading Southern East Pacific Rise (SEPR) near the equator. This expedition follows the work of a 2005 expedition by R/V Dayangyihao, during which water column turbidity anomalies were measured in the region. The newly discovered <span class="hlt">vent</span> fields are located along a 22-km-long ridge segment of the SEPR at 102.655°W/2.22°S, 102.646°W/2.152°S, 102.619°W/2.078°S, and 102.62°W/2.02°S, respectively, as well as on an off-axial volcano near 102.456°W/1.369°S. A significant portion of the activity appears to be concentrated along the edges of a seafloor fissure system. Furthermore, water column turbidity anomalies were observed over off-axis volcanoes near 102.827°W/2.084°S and 102.58°W/2.019°S. Video footage of the <span class="hlt">vent</span> fields and water column turbidity, temperature, and methane anomalies were recorded by a deep-towed integrated system consisting of video, still camera, CTD, and ADCP, and MAPR and METS sensors. Two active <span class="hlt">hydrothermal</span> fields at 2.217°S and 2.023°S were then extensively photographed and surveyed using the autonomous underwater vehicle ABE of the Woods Hole Oceanographic Institution (WHOI). Four samples of <span class="hlt">hydrothermal</span> chimneys were successfully obtained by a TV-guided grab in three locations, showing evidence of high-temperature <span class="hlt">hydrothermal</span> <span class="hlt">venting</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3218092','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3218092"><span id="translatedtitle">Conjugating effects of symbionts and environmental factors on gene expression in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussels</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2011-01-01</p> <p>Background The deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel Bathymodiolus azoricus harbors thiotrophic and methanotrophic symbiotic bacteria in its gills. While the symbiotic relationship between this <span class="hlt">hydrothermal</span> mussel and these chemoautotrophic bacteria has been described, the molecular processes involved in the cross-talking between symbionts and host, in the maintenance of the symbiois, in the influence of environmental parameters on gene expression, and in transcriptome variation across individuals remain poorly understood. In an attempt to understand how, and to what extent, this double symbiosis affects host gene expression, we used a transcriptomic approach to identify genes potentially regulated by symbiont characteristics, environmental conditions or both. This study was done on mussels from two contrasting populations. Results Subtractive libraries allowed the identification of about 1000 genes putatively regulated by symbiosis and/or environmental factors. Microarray analysis showed that 120 genes (3.5% of all genes) were differentially expressed between the Menez Gwen (MG) and Rainbow (Rb) <span class="hlt">vent</span> fields. The total number of regulated genes in mussels harboring a high versus a low symbiont content did not differ significantly. With regard to the impact of symbiont content, only 1% of all genes were regulated by thiotrophic (SOX) and methanotrophic (MOX) bacteria content in MG mussels whereas 5.6% were regulated in mussels collected at Rb. MOX symbionts also impacted a higher proportion of genes than SOX in both <span class="hlt">vent</span> fields. When host transcriptome expression was analyzed with respect to symbiont gene expression, it was related to symbiont quantity in each field. Conclusions Our study has produced a preliminary description of a transcriptomic response in a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel host of both thiotrophic and methanotrophic symbiotic bacteria. This model can help to identify genes involved in the maintenance of symbiosis or regulated by environmental parameters. Our results provide evidence of symbiont effect on transcriptome regulation, with differences related to type of symbiont, even though the relative percentage of genes involved remains limited. Differences observed between the <span class="hlt">vent</span> <span class="hlt">site</span> indicate that environment strongly influences transcriptome regulation and impacts both activity and relative abundance of each symbiont. Among all these genes, those participating in recognition, the immune system, oxidative stress, and energy metabolism constitute new promising targets for extended studies on symbiosis and the effect of environmental parameters on the symbiotic relationships in B. azoricus. PMID:22034982</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4585236','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4585236"><span id="translatedtitle">Biogeography and evolution of Thermococcus isolates from <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems of the Pacific</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Price, Mark T.; Fullerton, Heather; Moyer, Craig L.</p> <p>2015-01-01</p> <p>Thermococcus is a genus of hyperthermophilic archaea that is ubiquitous in marine <span class="hlt">hydrothermal</span> environments growing in anaerobic subsurface habitats but able to survive in cold oxygenated seawater. DNA analyses of Thermococcus isolates were applied to determine the relationship between geographic distribution and relatedness focusing primarily on isolates from the Juan de Fuca Ridge and South East Pacific Rise. Amplified fragment length polymorphism (AFLP) analysis and multilocus sequence typing (MLST) were used to resolve genomic differences in 90 isolates of Thermococcus, making biogeographic patterns and evolutionary relationships apparent. Isolates were differentiated into regionally endemic populations however there was also evidence in some lineages of cosmopolitan distribution. The biodiversity identified in Thermococcus isolates and presence of distinct lineages within the same <span class="hlt">vent</span> <span class="hlt">site</span> suggests the utilization of varying ecological niches in this genus. In addition to resolving biogeographic patterns in Thermococcus, this study has raised new questions about the closely related Pyrococcus genus. The phylogenetic placement of Pyrococcus type strains shows the close relationship between Thermococcus and Pyrococcus and the unresolved divergence of these two genera. PMID:26441901</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26283348','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26283348"><span id="translatedtitle">Endosymbionts escape dead <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworms to enrich the free-living population.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Klose, Julia; Polz, Martin F; Wagner, Michael; Schimak, Mario P; Gollner, Sabine; Bright, Monika</p> <p>2015-09-01</p> <p>Theory predicts that horizontal acquisition of symbionts by plants and animals must be coupled to release and limited dispersal of symbionts for intergenerational persistence of mutualisms. For deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworms (Vestimentifera, Siboglinidae), it has been demonstrated that a few symbiotic bacteria infect aposymbiotic host larvae and grow in a newly formed organ, the trophosome. However, whether viable symbionts can be released to augment environmental populations has been doubtful, because (i) the adult worms lack obvious openings and (ii) the vast majority of symbionts has been regarded as terminally differentiated. Here we show experimentally that symbionts rapidly escape their hosts upon death and recruit to surfaces where they proliferate. Estimating symbiont release from our experiments taken together with well-known tubeworm density ranges, we suggest a few million to 1.5 billion symbionts seeding the environment upon death of a tubeworm clump. In situ observations show that such clumps have rapid turnover, suggesting that release of large numbers of symbionts may ensure effective dispersal to new <span class="hlt">sites</span> followed by active larval colonization. Moreover, release of symbionts might enable adaptations that evolve within host individuals to spread within host populations and possibly to new environments. PMID:26283348</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26441901','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26441901"><span id="translatedtitle">Biogeography and evolution of Thermococcus isolates from <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems of the Pacific.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Price, Mark T; Fullerton, Heather; Moyer, Craig L</p> <p>2015-01-01</p> <p>Thermococcus is a genus of hyperthermophilic archaea that is ubiquitous in marine <span class="hlt">hydrothermal</span> environments growing in anaerobic subsurface habitats but able to survive in cold oxygenated seawater. DNA analyses of Thermococcus isolates were applied to determine the relationship between geographic distribution and relatedness focusing primarily on isolates from the Juan de Fuca Ridge and South East Pacific Rise. Amplified fragment length polymorphism (AFLP) analysis and multilocus sequence typing (MLST) were used to resolve genomic differences in 90 isolates of Thermococcus, making biogeographic patterns and evolutionary relationships apparent. Isolates were differentiated into regionally endemic populations however there was also evidence in some lineages of cosmopolitan distribution. The biodiversity identified in Thermococcus isolates and presence of distinct lineages within the same <span class="hlt">vent</span> <span class="hlt">site</span> suggests the utilization of varying ecological niches in this genus. In addition to resolving biogeographic patterns in Thermococcus, this study has raised new questions about the closely related Pyrococcus genus. The phylogenetic placement of Pyrococcus type strains shows the close relationship between Thermococcus and Pyrococcus and the unresolved divergence of these two genera. PMID:26441901</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5771688','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5771688"><span id="translatedtitle">Extremely thermophilic fermentative archaebacteria of the genus desulfurococcus from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Technical report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jannasch, H.W.; Wirsen, C.O.; Molyneaux, S.J.; Langworthy, T.A.</p> <p>1988-05-01</p> <p>Two strains of extremely thermophilic, anaerobic bacteria are described that are representative of isolates obtained from a variety of oceanic <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> at depths from 2,000 to 3,700 m. The isolates were similar in their requirements for complex organic media, elemental sulfur, and seawater-range salinities (optimum, 2.1 to 2.4%); their high tolerance for sulfide (100 mM) and oxic conditions below growth-range temperatures (50 to 95%C); and their archaebacterial characteristics: absence of murein, presence of certain di-and tetraethers, and response to specific antibiotics. The two strains (S and SY, respectively) differed slightly in their optimum growth temperatures (85 and 90 C), optimum pHs for growth (7.5 and 7.0), and DNA base compositions (52.01 and 52.42 G+C mol%). At their in situ pressure of about 250 atm (25,313 kPa), growth rates at 80 and 90 C were about 40% lower than those at 1 atm (101.29 kPa), and no growth occurred at 100 and 110 C, respectively, at either pressure. In yeast extract medium, only 2% of the organic carbon was used and appeared to stem largely from the proteinaceous constituents. According to physiological criteria, the isolates belong to the genus Desulfurococcus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1762412','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1762412"><span id="translatedtitle">The Sound Generated by Mid-Ocean Ridge Black Smoker <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Crone, Timothy J.; Wilcock, William S.D.; Barclay, Andrew H.; Parsons, Jeffrey D.</p> <p>2006-01-01</p> <p><span class="hlt">Hydrothermal</span> flow through seafloor black smoker <span class="hlt">vents</span> is typically turbulent and vigorous, with speeds often exceeding 1 m/s. Although theory predicts that these flows will generate sound, the prevailing view has been that black smokers are essentially silent. Here we present the first unambiguous field recordings showing that these <span class="hlt">vents</span> radiate significant acoustic energy. The sounds contain a broadband component and narrowband tones which are indicative of resonance. The amplitude of the broadband component shows tidal modulation which is indicative of discharge rate variations related to the mechanics of tidal loading. <span class="hlt">Vent</span> sounds will provide researchers with new ways to study flow through sulfide structures, and may provide some local organisms with behavioral or navigational cues. PMID:17205137</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUSMEP31A..03C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUSMEP31A..03C"><span id="translatedtitle">Geothermic Potential Assessment of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> of Township Barranca De Upia - Meta - Colombia</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chica, J.; Chicangana, G.; Eco Energy Research Group</p> <p>2013-05-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> have been traditionally exploited in Colombia as a source of tourism revenue such as pools and saunas. Leaving aside its high potential for geothermal power generation in applications like heating, drying, cooling, extensive use in crops, livestock, electricity generation and more. Currently the use given to this natural resource in the town of Barranca de Upia in Meta department, central Colombia, is like Wellness Centre. However, the geothermal gradient for the area where <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> occur, indicates that the water emerges at temperatures above 70 ° C (Alfaro et al., 2003), which opens a window of opportunity to assess their geothermal potential, in order to know the actual energy potential of the region as an option of augmenting their development. this research is the analysis of information gathered from databases in gravimetry and magnetometry of the study area and the temperatures measured in wells derived from the oil industry. Based on that information, a numerical analysis of the data will be performed in order to establish a model to parameterize the energy potential of the study area and identify possible uses of the energy contained by the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3635849','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3635849"><span id="translatedtitle">Biogeography of Persephonella in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> of the Western Pacific</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Mino, Sayaka; Makita, Hiroko; Toki, Tomohiro; Miyazaki, Junichi; Kato, Shingo; Watanabe, Hiromi; Imachi, Hiroyuki; Watsuji, Tomo-o; Nunoura, Takuro; Kojima, Shigeaki; Sawabe, Tomoo; Takai, Ken; Nakagawa, Satoshi</p> <p>2013-01-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields are areas on the seafloor with high biological productivity fueled by microbial chemosynthesis. Members of the Aquificales genus Persephonella are obligately chemosynthetic bacteria, and appear to be key players in carbon, sulfur, and nitrogen cycles in high temperature habitats at deep-sea <span class="hlt">vents</span>. Although this group of bacteria has cosmopolitan distribution in deep-sea <span class="hlt">hydrothermal</span> ecosystem around the world, little is known about their population structure such as intraspecific genomic diversity, distribution pattern, and phenotypic diversity. We developed the multi-locus sequence analysis (MLSA) scheme for their genomic characterization. Sequence variation was determined in five housekeeping genes and one functional gene of 36 Persephonella hydrogeniphila strains originated from the Okinawa Trough and the South Mariana Trough (SNT). Although the strains share >98.7% similarities in 16S rRNA gene sequences, MLSA revealed 35 different sequence types (ST), indicating their extensive genomic diversity. A phylogenetic tree inferred from all concatenated gene sequences revealed the clustering of isolates according to the geographic origin. In addition, the phenotypic clustering pattern inferred from whole-cell matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis can be correlated to their MLSA clustering pattern. This study represents the first MLSA combined with phenotypic analysis indicative of allopatric speciation of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> bacteria. PMID:23630523</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26147346','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26147346"><span id="translatedtitle">Functional interactions among filamentous Epsilonproteobacteria and Bacteroidetes in a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> biofilm.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stokke, Runar; Dahle, Håkon; Roalkvam, Irene; Wissuwa, Juliane; Daae, Frida Lise; Tooming-Klunderud, Ave; Thorseth, Ingunn H; Pedersen, Rolf B; Steen, Ida Helene</p> <p>2015-10-01</p> <p>Little is known about how lithoautotrophic primary production is connected to microbial organotrophic consumption in <span class="hlt">hydrothermal</span> systems. Using a multifaceted approach, we analysed the structure and metabolic capabilities within a biofilm growing on the surface of a black smoker chimney in the Loki's Castle <span class="hlt">vent</span> field. Imaging revealed the presence of rod-shaped Bacteroidetes growing as ectobionts on long, sheathed microbial filaments (>?100??m) affiliated with the Sulfurovum genus within Epsilonproteobacteria. The filaments were composed of a thick (>?200?nm) stable polysaccharide, representing a substantial fraction of organic carbon produced by primary production. An integrated -omics approach enabled us to assess the metabolic potential and in situ metabolism of individual taxonomic and morphological groups identified by imaging. Specifically, we provide evidence that organotrophic Bacteroidetes attach to and glide along the surface of Sulfurovum filaments utilizing organic polymers produced by the lithoautotrophic Sulfurovum. Furthermore, in situ expression of acetyl-CoA synthetase by Sulfurovum suggested the ability to assimilate acetate, indicating recycling of organic matter in the biofilm. This study expands our understanding of the lifestyles of Epsilonproteobacteria in <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, their metabolic properties and co-operative interactions in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> food webs. PMID:26147346</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26250301','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26250301"><span id="translatedtitle">New Sericosura (Pycnogonida:Ammotheidae) from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the Southern Ocean.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Arango, Claudia P; Linse, Katrin</p> <p>2015-01-01</p> <p>Three new species of Sericosura (Pycnogonida: Ammotheidae) are described from recently discovered <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the East Scotia Ridge, Southern Ocean: Sericosura bamberi sp. nov., S. dimorpha sp. nov. and S. curva sp. nov. The eleven species known to date in the genus Sericosura are all inhabitants of chemosynthetic environments in different oceans around the world.        Morphology and preliminary DNA data from the COI locus suggest the East Scotia Ridge pycnogonids have relatively close evolutionary affinities with species known from the East Pacific Rise and the Mid-Atlantic Ridge. This finding highlights the importance of Sericosura as a characteristic taxon of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> and the great potential of this genus for global scale ecological and evolutionary studies of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> fauna.        The use of pycnogonid DNA data combined with recent models explaining biogeographic provinces along the mid-ocean ridge system should prove extremely useful to understanding the patterns of diversification of endemic fauna from chemosynthetic environments and from the deep-sea in general. PMID:26250301</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2396607','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2396607"><span id="translatedtitle">Formation of Zn- and Fe-sulfides near <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> at the Eastern Lau Spreading Center: implications for sulfide bioavailability to chemoautotrophs</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hsu-Kim, Heileen; Mullaugh, Katherine M; Tsang, Jeffrey J; Yucel, Mustafa; Luther, George W</p> <p>2008-01-01</p> <p>Background The speciation of dissolved sulfide in the water immediately surrounding deep-ocean <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> is critical to chemoautotrophic organisms that are the primary producers of these ecosystems. The objective of this research was to identify the role of Zn and Fe for controlling the speciation of sulfide in the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields at the Eastern Lau Spreading Center (ELSC) in the southern Pacific Ocean. Compared to other well-studied <span class="hlt">hydrothermal</span> systems in the Pacific, the ELSC is notable for unique ridge characteristics and gradients over short distances along the north-south ridge axis. Results In June 2005, diffuse-flow (< 50°C) and high-temperature (> 250°C) <span class="hlt">vent</span> fluids were collected from four field <span class="hlt">sites</span> along the ELSC ridge axis. Total and filtered Zn and Fe concentrations were quantified in the <span class="hlt">vent</span> fluid samples using voltammetric and spectrometric analyses. The results indicated north-to-south variability in <span class="hlt">vent</span> fluid composition. In the high temperature <span class="hlt">vent</span> fluids, the ratio of total Fe to total Zn varied from 39 at Kilo Moana, the most northern <span class="hlt">site</span>, to less than 7 at the other three <span class="hlt">sites</span>. The concentrations of total Zn, Fe, and acid-volatile sulfide indicated that oversaturation and precipitation of sphalerite (ZnS(s)) and pyrite (FeS2(s)) were possible during cooling of the <span class="hlt">vent</span> fluids as they mixed with the surrounding seawater. In contrast, most samples were undersaturated with respect to mackinawite (FeS(s)). The reactivity of Zn(II) in the filtered samples was tested by adding Cu(II) to the samples to induce metal-exchange reactions. In a portion of the samples, the concentration of labile Zn2+ increased after the addition of Cu(II), indicating the presence of strongly-bound Zn(II) species such as ZnS clusters and nanoparticles. Conclusion Results of this study suggest that Zn is important to sulfide speciation at ELSC <span class="hlt">vent</span> habitats, particularly at the southern <span class="hlt">sites</span> where Zn concentrations increase relative to Fe. As the <span class="hlt">hydrothermal</span> fluids mix with the ambient seawater, Zn-sulfide clusters and nanoparticles are likely preventing sulfide oxidation by O2 and reducing bioavailability of S(-II) to organisms. PMID:18489753</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26439286','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26439286"><span id="translatedtitle">Characterization of miRNAs from <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> shrimp Rimicaris exoculata.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhou, Yadong; He, Yaodong; Wang, Chunsheng; Zhang, Xiaobo</p> <p>2015-12-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> shrimp Rimicaris exoculata is a dominant species aggregating in <span class="hlt">vent</span> fields along the Mid-Atlantic Ocean Ridge. MicroRNAs play important roles in life cycles of eukaryotes. However, little is known about miRNAs of <span class="hlt">vent</span> animals. In the present study, a small RNA cDNA library from the muscle of R. exoculata was constructed and the miRNA sequencing was performed. The results indicated that a total of 7,983,331 raw reads were obtained, representing 569,354 unique sequences. Based on sequence analysis, R. exoculata contained 159 conserved miRNAs and 34 novel miRNAs. The conserved miRNAs included 54 families belonging to three different taxonomic units (bilaterian, protostomes and arthropods). The results also showed that miR-2001, a lost miRNA in crustaceans, existed in R. exoculata. Among the conserved miRNAs, iso-miRs were detected. Therefore, this study presented the first insight into the miRNAs of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> animals. PMID:26439286</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5705468','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5705468"><span id="translatedtitle">Sound field near <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on Axial Seamount, Juan de Fuca Ridge. Technical report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Little, S.A.; Stolzenbach, K.D.; Purdy, G.M.</p> <p>1990-08-10</p> <p>High-quality acoustic noise measurements were obtained by two hydrophones located 3 m and 40 m from an active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> on Axial Seamount, Juan de Fuca Ridge, in an effort to determine the feasibility of monitoring <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> activity through flow noise generation. Most of the measured noise field could be attributed to ambient ocean noise sources of microseisms, distant shipping, and weather, punctuated by local ships and biological sources. Long-period, low-velocity, water/rock interface waves were detected with high amplitudes which rapidly decayed with distance from the seafloor. Detection of <span class="hlt">vent</span> signals was hampered by unexpected spatial nonstationarity due to the shadowing effects of the calders wall. No continuous <span class="hlt">vent</span> signals were deemed significant based on a criterion of 90% probability of detection and 5% probability of false alarm. However, a small signal near 40 Hz, with a power level of 0.0001 Pa sq/Hz was noticed on two records taken within 3 m of the Inferno black smoker. The frequency of this signal is consistent with predictions, and the power level suggests the occurrence of jet noise amplification due to convected density inhomogeneities. Keywords: Seamounts; Flow noise; Underwater acoustics; Acoustic measurement; Geothermy/noise; Ocean ridges; Underwater sound signals; Reprints; North Pacific Ocean. (EDC).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001DSRI...48.1325D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001DSRI...48.1325D"><span id="translatedtitle">Variations in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> communities on the Mid-Atlantic Ridge near the Azores plateau</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Desbruyères, D.; Biscoito, M.; Caprais, J.-C.; Colaço, A.; Comtet, T.; Crassous, P.; Fouquet, Y.; Khripounoff, A.; Le Bris, N.; Olu, K.; Riso, R.; Sarradin, P.-M.; Segonzac, M.; Vangriesheim, A.</p> <p>2001-05-01</p> <p>Near the Azores Triple Junction as the Azores Plateau is approached, the ridge axis becomes shallower; its depth decreases from ca. 2400 m in the R AINBOW <span class="hlt">vent</span> field (36°13'N) to ca. 850 m in the M ENEZ G WEN <span class="hlt">vent</span> field (37°35'N). In this area, extensive mussel beds of the mytilid Bathymodiolus azoricus dominate the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fauna, along with populations of three shrimps ( Rimicaris exoculata, Mirocaris fortunata and Chorocaris chacei). The main physical and chemical characteristics of the <span class="hlt">vent</span> habitat were studied by discrete sampling, in situ analysis and sediment trap moorings. The <span class="hlt">vent</span> fauna is distributed along a variable band where the <span class="hlt">vent</span> fluids and seawater mix, with R. exoculata living in the most concentrated areas and Bathymodiolus azoricus in the most diluted zones. Various non-endemic species live at the border of the <span class="hlt">vent</span> field. The variations observed in structure and composition of the communities along the depth gradient are most likely due to changes in <span class="hlt">vent</span> fluid toxicity (metallic and sulphide content) and suspended mineral particles, which render the fluids harsher for species living there. The main faunal differences observed between L UCKY S TRIKE and M ENEZ G WEN <span class="hlt">hydrothermal</span> fields are due to an impoverishment in the <span class="hlt">hydrothermal</span> endemic species and to the penetration of bathyal species. The comparison of the three studied <span class="hlt">vent</span> fields suggests the existence of a succession of several biogeographic islands rather than a single province.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DSRI..106..154L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DSRI..106..154L"><span id="translatedtitle">Temporal and spatial variation in temperature experienced by macrofauna at Main Endeavour <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Raymond W.; Robert, Katleen; Matabos, Marjolaine; Bates, Amanda E.; Juniper, S. Kim</p> <p>2015-12-01</p> <p>A significant focus of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecological studies has been to understand how species cope with various stressors through physiological tolerance and biochemical resistance. Yet, the environmental conditions experienced by <span class="hlt">vent</span> species have not been well characterized. This objective requires continuous observations over time intervals that can capture environmental variability at scales that are relevant to animals. We used autonomous temperature logger arrays (four roughly parallel linear arrays of 12 loggers spaced every 10-12 cm) to study spatial and temporal variations in the thermal regime experienced by <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> macrofauna at a diffuse flow <span class="hlt">vent</span>. Hourly temperatures were recorded over eight months from 2010 to 2011 at Grotto <span class="hlt">vent</span> in the Main Endeavour <span class="hlt">vent</span> field on the Juan de Fuca Ridge, a focus area of the Ocean Networks Canada cabled observatory. The conspicuous animal assemblages in video footage contained Ridgeia piscesae tubeworms, gastropods (primarily Lepetodrilus fucensis), and polychaetes (polynoid scaleworms and the palm worm Paralvinella palmiformis). Two dimensional spatial gradients in temperature were generally stable over the deployment period. The average temperature recorded by all arrays, and in some individual loggers, revealed distinctive fluctuations in temperature that often corresponded with the tidal cycle. We postulate that this may be related to changes in bottom currents or fluctuations in <span class="hlt">vent</span> discharge. A marked transient temperature increase lasting over a period of days was observed in April 2011. While the distributions and behavior of Juan de Fuca Ridge <span class="hlt">vent</span> invertebrates may be partially constrained by environmental temperature and temperature tolerance, except for the one transient high-temperature event, observed fluid temperatures were generally similar to the thermal preferences for some species, and typically well below lethal temperatures for all species. Average temperatures of the four arrays ranged from 4.1 to 11.0 °C during the deployment, indicating that on an hourly timescale the temperature conditions in this tubeworm community were fairly moderate and stable. The generality of these findings and behavioral responses of <span class="hlt">vent</span> organisms to predictable rhythmicity and non-periodic temperature shifts are areas for further investigation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dspace.mit.edu/handle/1721.1/97145','EPRINT'); return false;" href="http://dspace.mit.edu/handle/1721.1/97145"><span id="translatedtitle">Distal transport of dissolved <span class="hlt">hydrothermal</span> iron in the deep South Pacific Ocean</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Fitzsimmons, Jessica N.</p> <p></p> <p>Until recently, <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> were not considered to be an important source to the marine dissolved Fe (dFe) inventory because <span class="hlt">hydrothermal</span> Fe was believed to precipitate quantitatively near the <span class="hlt">vent</span> <span class="hlt">site</span>. Based on ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.V41B1393K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.V41B1393K"><span id="translatedtitle">Characterization of Dissolved Organic Matter from Deep-sea Floor <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> in South Mariana Backarc Spreading Center</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kitajima, F.; Yamanaka, T.</p> <p>2004-12-01</p> <p>In South Mariana Backarc Spreading Center, a few active <span class="hlt">hydrothermal</span> fields are located. We investigated a characterization of dissolved organic matter (DOM) from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in this area, in order to clarify the biosphere beneath deep-sea floor. Hot water sample was collected from a drilled hole (APM01 located in Fryer <span class="hlt">site</span>, 12o 55.22fN, 143o 37.16fE, depth 2850m) during the ROPOS/TN167A cruise in March 2004. The hole had been drilled during Hakurei-Maru 2 cruise in January 2004. Another hot water sample was collected from a natural black smoker located in Pika <span class="hlt">site</span> (12o 55.15fN, 143o 36.96fE, depth 2773m) during YK03-09 cruise. In this investigation, we developed a standalone filtration system in order to collect and enrich dissolved organic matter of quite low concentration. This system was designed to be put near <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> for at least 24h. This system has an ODS disk (EmporeTM High Performance Extraction Disk C18 90mm?) with a pre-filter (Whatman GMF 1 ?)m filter paper) to adsorb dilute organics. We collected DOM from the APM01 casing pipe for about 30h (Tmax = 25-30 o C, the estimated volume of filtrated water is max. 300L) using this filtration system. Adsorbed organics were eluted with methanol for 12h twice and toluene once using soxhlet extractor. Recovered amounts of methanol eluents are 72.8mg for APM01, and 89.7mg for the black smoker. Prior to GCMS analysis, we carried out high resolution 1 H-NMR measurement (400MHz), together with the DOM samples collected from the Suiyo Seamount in July-August 2001 and August 2002. Most of the samples show signals in the region of 3-4 ppm, and the samples from the <span class="hlt">vents</span> of relatively low temperatures (APM01 and AP04: the natural <span class="hlt">vent</span> at the Suiyo Seamount, temperature 8-48o C ) show signals also in the region of 0.8-1.6 ppm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.B32B..02P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.B32B..02P"><span id="translatedtitle">Bioavailability, Bioaccumulation and Biotransformation of arsenic in coral reef organisms surrounding an arsenic-rich marine shallow-water <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> system in the coastal waters of Ambitle Island, Papua New Guinea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pichler, T.; Wallschläger, D.; Price, R. E.</p> <p>2009-12-01</p> <p>Marine shallow-water <span class="hlt">hydrothermal</span> systems are often enriched in biologically toxic elements, thus making them ideal natural analogs for coastal anthropogenic pollution. Here, we report our investigation of the bioavailability, bioaccumulation, and biotransformation of <span class="hlt">hydrothermally</span>-derived arsenic into several coral reef organisms from the arsenic-rich marine shallow-water <span class="hlt">hydrothermal</span> system of Tutum Bay, Ambitle Island, in northeastern Papua New Guinea. <span class="hlt">Hydrothermal</span> <span class="hlt">venting</span> provided bioavailable As by two major pathways throughout Tutum Bay: 1) easily-exchangeable As from <span class="hlt">hydrothermally</span> influenced sediments to as far away as 200 m from focused <span class="hlt">venting</span>, and 2) in surface seawaters, which may allow for biological uptake by phytoplankton and transfer up the food web. The soft coral Clavularia sp., the calcareous algae Halimeda sp., and the tunicate Polycarpa sp. collected from the <span class="hlt">hydrothermal</span> area each displayed distinctly higher (up to 20 times) total arsenic compared to the control <span class="hlt">site</span>, with increasing trends while approaching focused <span class="hlt">hydrothermal</span> <span class="hlt">venting</span>. Organic and inorganic arsenic species were extracted intact from the tissues of each organism, separated by anion exchange chromatography, and analyzed by inductively-coupled plasma-dynamic reaction cell-mass spectrometry. Overall, speciation patterns for Clavularia were similar for the control <span class="hlt">site</span> versus the <span class="hlt">hydrothermal</span> <span class="hlt">site</span>, although the concentrations were much higher. Elevated concentrations of DMA and cationic forms of arsenic, most likely AB, in Clavularia, both from the control <span class="hlt">site</span> and from the <span class="hlt">hydrothermal</span> area suggest its metabolic pathway is not altered due to <span class="hlt">hydrothermal</span> activity, and is similar to other marine organisms. Arsenic speciation patterns in Polycarpa were also similar for both <span class="hlt">sites</span>, and suggests uptake of arsenic via food chain, containing neither As(III) nor As(V), but abundant excluded As and DMA. It is unclear if methylation is taking place within this organism or prior to ingestion. Elevated concentrations of As(III) in Halimeda from the <span class="hlt">hydrothermal</span> system suggest this organism is not efficient at methylating inorganic arsenic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3721025','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3721025"><span id="translatedtitle">Diffuse flow environments within basalt- and sediment-based <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystems harbor specialized microbial communities</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Campbell, Barbara J.; Polson, Shawn W.; Zeigler Allen, Lisa; Williamson, Shannon J.; Lee, Charles K.; Wommack, K. Eric; Cary, S. Craig</p> <p>2013-01-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> differ both in surface input and subsurface geochemistry. The effects of these differences on their microbial communities are not clear. Here, we investigated both alpha and beta diversity of diffuse flow-associated microbial communities emanating from <span class="hlt">vents</span> at a basalt-based <span class="hlt">hydrothermal</span> system along the East Pacific Rise (EPR) and a sediment-based <span class="hlt">hydrothermal</span> system, Guaymas Basin. Both Bacteria and Archaea were targeted using high throughput 16S rRNA gene pyrosequencing analyses. A unique aspect of this study was the use of a universal set of 16S rRNA gene primers to characterize total and diffuse flow-specific microbial communities from varied deep-sea <span class="hlt">hydrothermal</span> environments. Both surrounding seawater and diffuse flow water samples contained large numbers of Marine Group I (MGI) Thaumarchaea and Gammaproteobacteria taxa previously observed in deep-sea systems. However, these taxa were geographically distinct and segregated according to type of spreading center. Diffuse flow microbial community profiles were highly differentiated. In particular, EPR dominant diffuse flow taxa were most closely associated with chemolithoautotrophs, and off axis water was dominated by heterotrophic-related taxa, whereas the opposite was true for Guaymas Basin. The diversity and richness of diffuse flow-specific microbial communities were strongly correlated to the relative abundance of Epsilonproteobacteria, proximity to macrofauna, and <span class="hlt">hydrothermal</span> system type. Archaeal diversity was higher than or equivalent to bacterial diversity in about one third of the samples. Most diffuse flow-specific communities were dominated by OTUs associated with Epsilonproteobacteria, but many of the Guaymas Basin diffuse flow samples were dominated by either OTUs within the Planctomycetes or hyperthermophilic Archaea. This study emphasizes the unique microbial communities associated with geochemically and geographically distinct <span class="hlt">hydrothermal</span> diffuse flow environments. PMID:23898323</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3670190','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3670190"><span id="translatedtitle">Arsenic speciation in food chains from mid-Atlantic <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Taylor, Vivien F.; Jackson, Brian P.; Siegfried, Matthew; Navratilova, Jana; Francesconi, Kevin A.; Kirshtein, Julie; Voytek, Mary</p> <p>2012-01-01</p> <p>Arsenic concentration and speciation were determined in benthic fauna collected from the Mid-Atlantic Ridge <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. The shrimp species, Rimicaris exoculata, the <span class="hlt">vent</span> chimney-dwelling mussel, Bathymodiolus azoricus, Branchipolynoe seepensis, a commensal worm of B. azoricus, and the gastropod Peltospira smaragdina showed variations in As concentration and in stable isotope (?13C and ?15N) signature between species, suggesting different sources of As uptake. Arsenic speciation showed arsenobetaine to be the dominant species in R. exoculata, whereas in B. azoricus and B. seepensis arsenosugars were most abundant, although arsenobetaine, dimethylarsinate, and inorganic arsenic were also observed, along with several unidentified species. Scrape samples from outside the <span class="hlt">vent</span> chimneys, covered with microbial mat, which is a presumed food source for many <span class="hlt">vent</span> organisms, contained high levels of total As, but organic species were not detectable. The formation of arsenosugars in pelagic environments is typically attributed to marine algae, and the pathway to arsenobetaine is still unknown. The occurrence of arsenosugars and arsenobetaine in these deep sea organisms, where primary production is chemolithoautotrophic and stable isotope analyses indicate food sources are of <span class="hlt">vent</span> origin, suggests that organic arsenicals can occur in a food web without algae or other photosynthetic life. PMID:23741175</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24725508','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24725508"><span id="translatedtitle">Impacts of anthropogenic disturbances at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystems: a review.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Van Dover, Cindy Lee</p> <p>2014-12-01</p> <p>Deep-sea <span class="hlt">hydrothermal-vent</span> ecosystems have stimulated decades of scientific research and hold promise of mineral and genetic resources that also serve societal needs. Some endemic taxa thrive only in <span class="hlt">vent</span> environments, and <span class="hlt">vent</span>-associated organisms are adapted to a variety of natural disturbances, from tidal variations to earthquakes and volcanic eruptions. In this paper, physicochemical and biological impacts of a range of human activities at <span class="hlt">vents</span> are considered. Mining is currently the only anthropogenic activity projected to have a major impact on <span class="hlt">vent</span> ecosystems, albeit at a local scale, based on our current understanding of ecological responses to disturbance. Natural recovery from a single mining event depends on immigration and larval recruitment and colonization; understanding processes and dynamics influencing life-history stages may be a key to effective minimization and mitigation of mining impacts. Cumulative impacts on benthic communities of several mining projects in a single region, without proper management, include possible species extinctions and shifts in community structure and function. PMID:24725508</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70043449','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70043449"><span id="translatedtitle">Arsenic speciation in food chains from mid-Atlantic <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Taylor, Vivien F.; Jackson, Brian P.; Siegfried, Matthew R.; Navratilova, Jana; Francesconi, Kevin A.; Kirshtein, Julie; Voytek, Mary</p> <p>2012-01-01</p> <p>Arsenic concentration and speciation were determined in benthic fauna collected from the Mid-Atlantic Ridge <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. The shrimp species, Rimicaris exoculata, the <span class="hlt">vent</span> chimney-dwelling mussel, Bathymodiolus azoricus, Branchipolynoe seepensis, a commensal worm of B. azoricus and the gastropod Peltospira smaragdina showed variations in As concentration and in stable isotope (?13C and ?15N) signature between species, suggesting different sources of As uptake. Arsenic speciation showed arsenobetaine to be the dominant species in R. exoculata, whereas in B. azoricus and B. seepensis arsenosugars were most abundant, although arsenobetaine, dimethylarsinate and inorganic arsenic were also observed, along with several unidentified species. Scrape samples from outside the <span class="hlt">vent</span> chimneys covered with microbial mat, which is a presumed food source for many <span class="hlt">vent</span> organisms, contained high levels of total As, but organic species were not detectable. The formation of arsenosugars in pelagic environments is typically attributed to marine algae, and the pathway to arsenobetaine is still unknown. The occurrence of arsenosugars and arsenobetaine in these deep sea organisms, where primary production is chemolithoautotrophic and stable isotope analyses indicate food sources are of <span class="hlt">vent</span> origin, suggests that organic arsenicals can occur in a foodweb without algae or other photosynthetic life.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.V53A4839S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.V53A4839S"><span id="translatedtitle">Heat Source for Active <span class="hlt">Venting</span> at the Lost City <span class="hlt">Hydrothermal</span> Field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Smith, J. E.; Germanovich, L. N.; Lowell, R. P.</p> <p>2014-12-01</p> <p>Located at the inside corner high of the Mid-Atlantic Ridge (MAR), 30°N and the Atlantis Transform Fault (ATF), the Atlantis Massif has been uplifted over the past ~2 my. The Southern Ridge of this massif hosts the Lost City <span class="hlt">Hydrothermal</span> Field (LCHF), an off-axis <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field with carbonate chimney ages surpassing 120,000 yrs. The fluids discharging at LCHF carry geochemical signals that show a direct interaction with serpentinites. However, mineralogical evidence suggests that peridotite hydration began early in the formation of oceanic core complexes and previous modeling results indicate that serpentinization is unlikely to generate the heat necessary to maintain current levels of discharge at LCHF. This work develops a model for the LCHF <span class="hlt">venting</span> based on the evidence of tectonic strain, detachment faulting, serpentinization, and convective fluid flow. We constrain fluid flow at the LCHF by <span class="hlt">vent</span> geochemistry, <span class="hlt">vent</span> temperature, seismically inferred faulting, and expected geothermal gradient ?100°C/km. Present understanding of tectonic processes at the intersection of MAR and ATF suggests that unroofing of the footwall and crustal flexing of the massif induced normal faults, which run parallel to the MAR, throughout the Southern Ridge. In the absence of the evidence of magmatism, we test the feasibility of the geothermal gradient to cause fluid circulation in the high-permeability, sub-vertical fault zone. Fluid circulation in the fault zone is complemented by the bulk porous flow driven through the Southern Ridge by the lateral temperature gradient between the cold water on the steep face along the ATF side and the hot interior of the massif. In this scenario, the high pH <span class="hlt">hydrothermal</span> fluids pass through the serpentinized zone before discharging as both high-temperature focused flow (40°-91°C) and low-temperature (?15°C) diffuse flow at the LCHF.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=182849','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=182849"><span id="translatedtitle">DNA-DNA Solution Hybridization Studies of the Bacterial Symbionts of <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Tube Worms (Riftia pachyptila and Tevnia jerichonana)</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Edwards, Deeanne B.; Nelson, Douglas C.</p> <p>1991-01-01</p> <p>The giant tube worm, Riftia pachyptila (phylum Vestimentifera), is known only from four widely separated sulfide-rich deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems. This invertebrate is nourished by intracellular, chemoautotrophic bacterial symbionts which reside in a specialized trophosome tissue. The symbiont has not been cultured independently and is believed to be acquired de novo by host larvae of each generation. In the current study, R. pachyptila symbiont DNA was purified from the two most distant <span class="hlt">sites</span> on the basis of its difference in density versus host DNA. These two standards were hybridized against trophosome DNAs of 13 individuals from the Guaymas Basin, Galapagos Rift, and 13°N <span class="hlt">vents</span>. This indicated that all R. pachyptila symbionts are conspecific and that the variability in DNA-DNA hybridization (relative binding ratio [RBR]) was comparable within or between widely separated <span class="hlt">vents</span>. The symbiont of another tube worm, Tevnia jerichonana, was found to be the same as that of R. pachyptila, the first case in which distinct hosts possess the same sulfur bacterial symbiont. By contrast, Lamellibrachia sp. (same class as T. jerichonana) showed insignificant RBR with the R. pachyptila symbiont. DNA derived from solely eucaryotic tissue of R. pachyptila showed a surprisingly high RBR (20 to 50) with density-separated DNA standards. With DNAs obtained from physically separated symbionts, independent solution hybridization experiments confirmed the above-described conclusions. Possible explanations for this host-symbiont homology are discussed. PMID:16348457</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16348457','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16348457"><span id="translatedtitle">DNA-DNA Solution Hybridization Studies of the Bacterial Symbionts of <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Tube Worms (Riftia pachyptila and Tevnia jerichonana).</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Edwards, D B; Nelson, D C</p> <p>1991-04-01</p> <p>The giant tube worm, Riftia pachyptila (phylum Vestimentifera), is known only from four widely separated sulfide-rich deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems. This invertebrate is nourished by intracellular, chemoautotrophic bacterial symbionts which reside in a specialized trophosome tissue. The symbiont has not been cultured independently and is believed to be acquired de novo by host larvae of each generation. In the current study, R. pachyptila symbiont DNA was purified from the two most distant <span class="hlt">sites</span> on the basis of its difference in density versus host DNA. These two standards were hybridized against trophosome DNAs of 13 individuals from the Guaymas Basin, Galapagos Rift, and 13 degrees N <span class="hlt">vents</span>. This indicated that all R. pachyptila symbionts are conspecific and that the variability in DNA-DNA hybridization (relative binding ratio [RBR]) was comparable within or between widely separated <span class="hlt">vents</span>. The symbiont of another tube worm, Tevnia jerichonana, was found to be the same as that of R. pachyptila, the first case in which distinct hosts possess the same sulfur bacterial symbiont. By contrast, Lamellibrachia sp. (same class as T. jerichonana) showed insignificant RBR with the R. pachyptila symbiont. DNA derived from solely eucaryotic tissue of R. pachyptila showed a surprisingly high RBR (20 to 50) with density-separated DNA standards. With DNAs obtained from physically separated symbionts, independent solution hybridization experiments confirmed the above-described conclusions. Possible explanations for this host-symbiont homology are discussed. PMID:16348457</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.T31A0486C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.T31A0486C"><span id="translatedtitle">The Acoustic Signature of High-Temperature Deep Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crone, T. J.; Wilcock, W. S.; Parsons, J. D.; Barclay, A. H.</p> <p>2005-12-01</p> <p>Motivated by a desire to find new measurements that might be sensitive to flow rate variations within mid-ocean ridge <span class="hlt">hydrothermal</span> systems, we have conducted field studies to collect passive acoustic measurements at black smoker <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> using two versions of a simple dual-hydrophone recording device capable of collecting continuous acoustic data for about one week at sampling rates of 1000--2000 Hz. We deployed the first-generation instrument on the Sully sulfide structure in the Main Endeavour Field of the Juan de Fuca Ridge during September of 2004. We were able to collect approximately 48 hours of data before the instrument was partially destroyed by <span class="hlt">venting</span> fluid. We are in the process of obtaining additional measurements in the same <span class="hlt">vent</span> field with a second-generation instrument. For the 2004 deployment, the <span class="hlt">venting</span> fluid produced an acoustic signal that was far above the background level at all measured frequencies. The acoustic spectrum contains a broadband signal that is weighted toward the low frequencies and extends to the Nyquist frequency at 500 Hz. The spectrum also contains several sharp peaks below 150 Hz. The signal is variable in time, with the broadband and peak amplitudes fluctuating by ~20 dB, and the frequencies of the sharp spectral peaks fluctuating by ~1--3 Hz. The complex nature of the acoustic signal suggests that more than one sound production mechanism is operating within the <span class="hlt">vent</span>. The sharp peaks suggest the presence of a resonant mechanism such as pipe resonance excited by turbulent flow. The high level of the broadband signal is not predicted by theoretical investigations of low Mach number jet acoustics. It is likely that another broadband sound source is present, which could be related to phase separation or to the mixing of different density fluids. More observations will be required to fully understand the basic mechanisms of sound production within black smoker chimneys.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS13B1731M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS13B1731M"><span id="translatedtitle">How Disturbance Influences Community Composition at <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span>: a Theoretical Model of Macrofaunal Coexistence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miller, A. D.; Hsing, P.; Roxburgh, S. H.; Shea, K.; Fisher, C. R.</p> <p>2012-12-01</p> <p>Biological communities at spreading centers experience a continuum of disturbance regimes, with fast spreading ridges characterized by relatively frequent tectonic and magmatic events, and slow spreading ridges displaying more stable environmental conditions. We develop a theoretical model to show how disturbance (or lack thereof) can influence the composition of biological communities at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Our model assumptions are based on empirical data, which show that macrofaunal species of interest (Riftia pachyptila, Bathymodiolus thermophilus, Calyptogena magnifica) establish in distinct microhabitats, based on availability of <span class="hlt">vent</span> fluids that nourish endosymbiotic chemoautotrophs. We focus on how these establishment strategies interact with species fecundity, and with disturbance frequency and intensity, to determine what types of strategies can coexist in the system. We find that species must adopt sufficiently different fecundity-establishment strategies to coexist in the community, though strict tradeoffs between fecundity and establishment ability are not required. Additionally, we describe how the strategies that lead to coexistence depend on habitat availability and disturbance regime. Though other coexistence mechanisms may also play a role, our findings suggest why communities within a single biogeographic province may vary with spreading rate (as from N to S along the East Pacific Rise), and what strategies will allow coexistence under different disturbance regimes. Understanding how changes to disturbance regimes influence community composition is very important, as commercial mining interests are rapidly developing plans to exploit the rich mineral resources associated with <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> and their activities will change the disturbance regime.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26101015','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26101015"><span id="translatedtitle">Microbial diversity and adaptation to high hydrostatic pressure in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> prokaryotes.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jebbar, Mohamed; Franzetti, Bruno; Girard, Eric; Oger, Philippe</p> <p>2015-07-01</p> <p>Prokaryotes inhabiting in the deep sea <span class="hlt">vent</span> ecosystem will thus experience harsh conditions of temperature, pH, salinity or high hydrostatic pressure (HHP) stress. Among the fifty-two piezophilic and piezotolerant prokaryotes isolated so far from different deep-sea environments, only fifteen (four Bacteria and eleven Archaea) that are true hyper/thermophiles and piezophiles have been isolated from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>; these belong mainly to the Thermococcales order. Different strategies are used by microorganisms to thrive in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in which "extreme" physico-chemical conditions prevail and where non-adapted organisms cannot live, or even survive. HHP is known to impact the structure of several cellular components and functions, such as membrane fluidity, protein activity and structure. Physically the impact of pressure resembles a lowering of temperature, since it reinforces the structure of certain molecules, such as membrane lipids, and an increase in temperature, since it will also destabilize other structures, such as proteins. However, universal molecular signatures of HHP adaptation are not yet known and are still to be deciphered. PMID:26101015</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25764538','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25764538"><span id="translatedtitle">Biogeography and ecology of the rare and abundant microbial lineages in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Anderson, Rika E; Sogin, Mitchell L; Baross, John A</p> <p>2015-01-01</p> <p>Environmental gradients generate countless ecological niches in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems, which foster diverse microbial communities. The majority of distinct microbial lineages in these communities occur in very low abundance. However, the ecological role and distribution of rare and abundant lineages, particularly in deep, hot subsurface environments, remain unclear. Here, we use 16S rRNA tag sequencing to describe biogeographic patterning and microbial community structure of both rare and abundant archaea and bacteria in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems. We show that while rare archaeal lineages and almost all bacterial lineages displayed geographically restricted community structuring patterns, the abundant lineages of archaeal communities displayed a much more cosmopolitan distribution. Finally, analysis of one high-volume, high-temperature fluid sample representative of the deep hot biosphere described a unique microbial community that differed from microbial populations in diffuse flow fluid or sulfide samples, yet the rare thermophilic archaeal groups showed similarities to those that occur in sulfides. These results suggest that while most archaeal and bacterial lineages in <span class="hlt">vents</span> are rare and display a highly regional distribution, a small percentage of lineages, particularly within the archaeal domain, are successful at widespread dispersal and colonization. PMID:25764538</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002JGRB..107.2130B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002JGRB..107.2130B"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">venting</span> along Earth's fastest spreading center: East Pacific Rise, 27.5°-32.3°</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baker, E. T.; Hey, R. N.; Lupton, J. E.; Resing, J. A.; Feely, R. A.; Gharib, J. J.; Massoth, G. J.; Sansone, F. J.; Kleinrock, M.; Martinez, F.; Naar, D. F.; Rodrigo, C.; Bohnenstiehl, D.; Pardee, D.</p> <p>2002-07-01</p> <p>During March/April 1998 we conducted detailed mapping and sampling of <span class="hlt">hydrothermal</span> plumes along six segments of Earth's fasting spreading mid-ocean ridge, 27.5°-32.3°S on the East Pacific Rise. We compared the distribution and chemistry of <span class="hlt">hydrothermal</span> plumes to geological indicators of long-term (spreading rate) and moderate-term (ridge inflation) variations in magmatic budget. In this large-offset, propagating rift setting, these geological indices span virtually the entire range found along fast spreading ridges worldwide. <span class="hlt">Hydrothermal</span> plumes overlaid ~60% of the length of superfast (>130 km/Myr) spreading axis surveyed and defined at least 14 separate <span class="hlt">vent</span> fields. We observed no plumes over the slower spreading propagating segments. Finer-scale variations in the magmatic budget also correlated with <span class="hlt">hydrothermal</span> activity, as the location of the five most intense plumes corresponded to subsegment peaks in ridge inflation. Along the entire ridge crest, the more inflated a ridge location the more likely it was to be overlain by a <span class="hlt">hydrothermal</span> plume. Plume chemistry mostly reflected discharge from mature <span class="hlt">vent</span> fields apparently unperturbed by magmatic activity within the last few years. Plume samples with high volatile/metal ratios, generally indicating recent seafloor volcanism, were scarce. Along-axis trends in both volatile (3He; CH4; ?pH, a proxy for CO2; and particulate S) and nonvolatile (Fe, Mn) species showed a first-order agreement with the trend of ridge inflation. Nevertheless, a broad correspondence between the concentration of volatile species in plumes and geological proxies of magma supply identifies a pervasive magmatic imprint on this superfast spreading group of ridge segments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMOS33F..07T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS33F..07T"><span id="translatedtitle">Two <span class="hlt">hydrothermal</span> active <span class="hlt">vents</span> were found at 13.2°S and 14°S of South Mid-Atlantic Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tao, C.; Li, H.; Yang, Y.; Ni, J.; Cui, R.; Chen, Y. J.; Li, J.; He, Y.; Huang, W.; Gai, Y.; Wang, Y.; Su, Y.; Cheng, Z.; Lu, Y.; Wu, Z.; Li, J.; Zhang, R.; He, L.; Chen, S.; Zhang, D.; Lei, J.; Wang, Y.; Dy115-21 Leg 4 Scientific Party</p> <p>2010-12-01</p> <p>During Nov. to Dec. 2009, the Leg 4 of the Chinese DY115-21 cruise has been launched on 13°S -14°S MAR by R/V DAYANGYIHAO, aimed to investigate <span class="hlt">hydrothermal</span> activity in the region. Two active <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> have been found at 13.2°S and 14°S, which are the southernmost <span class="hlt">hydrothermal</span> fields known so far on the MAR. Samples including the sulfide chimney and basalt have been successfully collected by TV-Grab at the 13.2°S field. Evidence of sulfide video and <span class="hlt">hydrothermal</span> anomalies indicated the existence of the 14°S <span class="hlt">hydrothermal</span> field. The 13.2°S <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> is located at 14.41°W 13.28°S at depth of about 2,288m. This <span class="hlt">venting</span> field lies on an N-S fissure belt in the axial uplift. Black smoker was video recorded while no <span class="hlt">hydrothermal</span> fauna was found. According to the X-ray diffraction analysis, the sulfides collected by TV-Grab mainly consist of sphalerite and marcasite. The 14°S <span class="hlt">hydrothermal</span> field is located on the slop of the volcano, which lies on the inside corner between the ridge axial and transform fault, at depth of about 2,900m.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeCoA.156..122M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeCoA.156..122M"><span id="translatedtitle">Investigation of extractable organic compounds in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids along the Mid-Atlantic Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McCollom, Thomas M.; Seewald, Jeffrey S.; German, Christopher R.</p> <p>2015-05-01</p> <p>The possibility that deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> may contain organic compounds produced by abiotic synthesis or by microbial communities living deep beneath the surface has led to numerous studies of the organic composition of <span class="hlt">vent</span> fluids. Most of these studies have focused on methane and other light hydrocarbons, while the possible occurrence of more complex organic compounds in the fluids has remained largely unstudied. To address this issue, the presence of higher molecular weight organic compounds in deep-sea <span class="hlt">hydrothermal</span> fluids was assessed at three <span class="hlt">sites</span> along the Mid-Atlantic Ridge that span a range of temperatures (51 to >360 °C), fluid compositions, and host-rock lithologies (mafic to ultramafic). Samples were obtained at several <span class="hlt">sites</span> within the Lucky Strike, Rainbow, and Lost City <span class="hlt">hydrothermal</span> fields. Three methods were employed to extract organic compounds for analysis, including liquid:liquid extraction, cold trapping on the walls of a coil of titanium tubing, and pumping fluids through cartridges filled with solid phase extraction (SPE) sorbents. The only samples to consistently yield high amounts of extractable organic compounds were the warm (51-91 °C), highly alkaline fluids from Lost City, which contained elevated concentrations of C8, C10, and C12n-alkanoic acids and, in some cases, trithiolane, hexadecanol, squalene, and cholesterol. Collectively, the C8-C12 acids can account for about 15% of the total dissolved organic carbon in the Lost City fluids. The even-carbon-number predominance of the alkanoic acids indicates a biological origin, but it is unclear whether these compounds are derived from microbial activity occurring within the <span class="hlt">hydrothermal</span> chimney proximal to the <span class="hlt">site</span> of fluid discharge or are transported from deeper within the system. <span class="hlt">Hydrothermal</span> fluids from the Lucky Strike and Rainbow fields were characterized by an overall scarcity of extractable dissolved organic compounds. Trace amounts of aromatic hydrocarbons including phenanthrenes and benzothiophene were the only compounds that could be identified as indigenous components of these fluids. Although hydrocarbons and fatty acids were observed in some samples, those compounds were likely derived from particulate matter or biomass entrained during fluid collection. In addition, extracts of some fluid samples from the Rainbow field were found to contain an unresolved complex mixture (UCM) of organic compounds. This UCM shared some characteristics with organic matter extracted from bottom seawater, suggesting that the organic matter observed in these samples might represent seawater-derived compounds that had persisted, albeit with partial alteration, during circulation through the <span class="hlt">hydrothermal</span> system. While there is considerable evidence that Rainbow and Lost City <span class="hlt">vent</span> fluids contain methane and other light hydrocarbons produced through abiotic reduction of inorganic carbon, we found no evidence for more complex organic compounds with an abiotic origin in the same fluids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25658053','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25658053"><span id="translatedtitle">Predicting the response of the deep-ocean microbiome to geochemical perturbations by <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Reed, Daniel C; Breier, John A; Jiang, Houshuo; Anantharaman, Karthik; Klausmeier, Christopher A; Toner, Brandy M; Hancock, Cathrine; Speer, Kevin; Thurnherr, Andreas M; Dick, Gregory J</p> <p>2015-08-01</p> <p>Submarine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> perturb the deep-ocean microbiome by injecting reduced chemical species into the water column that act as an energy source for chemosynthetic organisms. These systems thus provide excellent natural laboratories for studying the response of microbial communities to shifts in marine geochemistry. The present study explores the processes that regulate coupled microbial-geochemical dynamics in <span class="hlt">hydrothermal</span> plumes by means of a novel mathematical model, which combines thermodynamics, growth and reaction kinetics, and transport processes derived from a fluid dynamics model. Simulations of a plume located in the ABE <span class="hlt">vent</span> field of the Lau basin were able to reproduce metagenomic observations well and demonstrated that the magnitude of primary production and rate of autotrophic growth are largely regulated by the energetics of metabolisms and the availability of electron donors, as opposed to kinetic parameters. Ambient seawater was the dominant source of microbes to the plume and sulphur oxidisers constituted almost 90% of the modelled community in the neutrally-buoyant plume. Data from drifters deployed in the region allowed the different time scales of metabolisms to be cast in a spatial context, which demonstrated spatial succession in the microbial community. While growth was shown to occur over distances of tens of kilometers, microbes persisted over hundreds of kilometers. Given that high-temperature <span class="hlt">hydrothermal</span> systems are found less than 100 km apart on average, plumes may act as important vectors between different <span class="hlt">vent</span> fields and other environments that are hospitable to similar organisms, such as oil spills and oxygen minimum zones. PMID:25658053</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3427048','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3427048"><span id="translatedtitle">Hydrogen-limited growth of hyperthermophilic methanogens at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ver Eecke, Helene C.; Butterfield, David A.; Huber, Julie A.; Lilley, Marvin D.; Olson, Eric J.; Roe, Kevin K.; Evans, Leigh J.; Merkel, Alexandr Y.; Cantin, Holly V.; Holden, James F.</p> <p>2012-01-01</p> <p>Microbial productivity at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> is among the highest found anywhere in the deep ocean, but constraints on microbial growth and metabolism at <span class="hlt">vents</span> are lacking. We used a combination of cultivation, molecular, and geochemical tools to verify pure culture H2 threshold measurements for hyperthermophilic methanogenesis in low-temperature <span class="hlt">hydrothermal</span> fluids from Axial Volcano and Endeavour Segment in the northeastern Pacific Ocean. Two Methanocaldococcus strains from Axial and Methanocaldococcus jannaschii showed similar Monod growth kinetics when grown in a bioreactor at varying H2 concentrations. Their H2 half-saturation value was 66 ?M, and growth ceased below 17–23 ?M H2, 10-fold lower than previously predicted. By comparison, measured H2 and CH4 concentrations in fluids suggest that there was generally sufficient H2 for Methanocaldococcus growth at Axial but not at Endeavour. Fluids from one <span class="hlt">vent</span> at Axial (Marker 113) had anomalously high CH4 concentrations and contained various thermal classes of methanogens based on cultivation and mcrA/mrtA analyses. At Endeavour, methanogens were largely undetectable in fluid samples based on cultivation and molecular screens, although abundances of hyperthermophilic heterotrophs were relatively high. Where present, Methanocaldococcus genes were the predominant mcrA/mrtA sequences recovered and comprised ?0.2–6% of the total archaeal community. Field and coculture data suggest that H2 limitation may be partly ameliorated by H2 syntrophy with hyperthermophilic heterotrophs. These data support our estimated H2 threshold for hyperthermophilic methanogenesis at <span class="hlt">vents</span> and highlight the need for coupled laboratory and field measurements to constrain microbial distribution and biogeochemical impacts in the deep sea. PMID:22869718</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25014334','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25014334"><span id="translatedtitle">Complete mitochondrial genome of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworm, Ridgeia piscesae (Polychaeta, Siboglinidae).</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jun, Jumin; Won, Yong-Jin; Vrijenhoek, Robert C</p> <p>2016-03-01</p> <p>The complete mitochondrial genome of Ridgeia piscesae (Polychaeta, Siboglinidae), one of the dominant taxa in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, is reported here for the first time. The R. piscesae mitogenome is 15,002?bp in total length and includes 13 protein-coding gene sequences, small and large rRNA sequences and 22 tRNA sequences. All genes are encoded on the heavy strand. The mitochondrial genomes of R. piscesae and other six polychaete species have a conserved gene order. PMID:25014334</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AIPC.1607..104C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AIPC.1607..104C"><span id="translatedtitle">The possible role of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in chemical evolution: Succinic acid radiolysis and thermolysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cruz-Castañeda, J.; Colín-García, M.; Negrón-Mendoza, A.</p> <p>2014-07-01</p> <p>In this research, the behavior under a high radiation field or high temperature of succinic acid, a dicarboxylic acid clue in metabolic routes, is studied. For this purpose, the molecule was irradiated with gamma rays in oxygen-free aqueous solutions, and the thermal decomposition was studied in a static system at temperatures up to 90 °C, simulating a white <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>. Our results indicate that a succinic acid is a relatively stable compound under irradiation. The gamma radiolysis yields carbon dioxide and di- and tricarboxylic acids such as malonic, carboxysuccinic, and citric acids. The main products obtained by the thermal treatment were CO2 and propionic acid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70014063','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70014063"><span id="translatedtitle">Fossils of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> worms from Cretaceous sulfide ores of the Samail ophiolite, Oman</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Haymon, R.M.; Koski, R.A.; Sinclair, C.</p> <p>1984-01-01</p> <p>Fossil worm tubes of Cretaceous age preserved in the Bayda massive sulfide deposit of the Samail ophiolite, Oman, are apparently the first documented examples of fossils embedded in massive sulfide deposits from the geologic record. The geologic setting of the Bayda deposit and the distinctive mineralogic and textural features of the fossiliferous samples suggest that the Bayda sulfide deposit and fossil fauna are remnants of a Cretaceous sea-floor <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> similar to modern hot springs on the East Pacific Rise and the Juan de Fuca Ridge.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013DSRII..92..172T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013DSRII..92..172T"><span id="translatedtitle">Population ecology of the tonguefish Symphurus thermophilus (Pisces; Pleuronectiformes; Cynoglossidae) at sulphur-rich <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on volcanoes of the northern Mariana Arc</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tunnicliffe, Verena; Tyler, Jennifer; Dower, John F.</p> <p>2013-08-01</p> <p>Flatfish are a major component of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> community on three seamounts of the northern Mariana Volcanic Arc in the northwest Pacific. Nikko, Kasuga-2 and Daikoku seamounts host <span class="hlt">vent</span> fields between 375 and 480 m depth where high temperature <span class="hlt">vents</span> release molten sulphur. The small cynoglossid tonguefish, Symphurus thermophilus Munroe and Hashimoto, is ubiquitous in all <span class="hlt">vent</span> habitats observed on these seamounts: among extensive fields of tubeworms and mussels and on solid sulphur surfaces on Nikko; on sulphur-rich sediments and barnacle-covered boulders on Kasuga-2; and on recent sulphur flows and on broad areas of loose and semi-consolidated sediments on Daikoku. We recorded repeated forays by individuals onto flows of molten sulphur as these surfaces cooled. Based on observations using ROVs, the mean density is 90 fish/m2 with maximum counts over 200 fish/m2 on Daikoku sediments. Compared to collected tonguefish from Daikoku and Kasuga-2, those from Nikko have significantly greater lengths and, on average, six times the mass. Otolith data indicate upper ages of 13 years with Nikko tonguefish growing significantly faster. Diets of tonguefish on the three seamounts reflect the different habitats and prey availability; in Daikoku specimens, small crustaceans and polychaetes are most common while on Nikko, gut contents are predominantly larger shrimp. We made the unusual observation of stunned midwater fish falling to the seafloor near the <span class="hlt">vents</span> where S. thermophilus immediately attacked them. This tonguefish has a wide diet range and foraging behaviour that likely influence the differing growth rates and sizes of fish inhabiting the different <span class="hlt">vent</span> <span class="hlt">sites</span>. Limited genetic data suggest that larval exchange probably occurs among <span class="hlt">sites</span> where the common habitat factor is high levels of elemental sulphur forming hard and partly unconsolidated substrata. Here, in the northern range of the Mariana Trench Marine National Monument, S. thermophilus, despite having an unusually broad habitat association, may be restricted in its overall range to this region of isolated volcanoes with active <span class="hlt">hydrothermalism</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.V11E2547A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.V11E2547A"><span id="translatedtitle">Microbially-Mediated Sulfur Oxidation in Diffuse <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Fluids at Axial Seamount, Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Akerman, N. H.; Butterfield, D. A.; Huber, J. A.</p> <p>2011-12-01</p> <p>Diffusely <span class="hlt">venting</span> <span class="hlt">hydrothermal</span> fluids can act as a window to the subseafloor microbial environment, where chemically-reduced <span class="hlt">hydrothermal</span> fluids mixing with oxygenated seawater in the shallow crust creates chemical disequilibria that chemotrophic microorganisms can exploit for energy gain. At Axial Seamount, an active deep-sea volcano located on the Juan de Fuca Ridge, sulfide concentrations have been measured as high as 5770 ?M, and sulfide oxidation is quantitatively the most important chemical energy source for microbial metabolism. In addition, studies of microbial population structure indicate that diffuse fluids at Axial are dominated by putative sulfur- and sulfide-oxidizing bacteria belonging to the Epsilonproteobacteria. To further study this important microbial process, we surveyed diffuse <span class="hlt">vent</span> samples from Axial over a range of temperature, pH, and sulfide concentrations for the presence and expression of sulfide-oxidizing bacteria using a functional gene approach. Dissolved oxygen concentrations decrease exponentially above 40°C and lower the potential for sulfide oxidation, so we identified six <span class="hlt">sites</span> of different temperatures, two each in the low (< 30°C), medium (~30°C), and high temperature (30 - 50°C) range. The low temperature <span class="hlt">sites</span> had sulfide-to-temperature ratios of 1 - 26, the medium from 15 - 29, and the high from 26 - 36. PCR primers were designed to target the sulfur oxidation gene soxB specifically from Epsilonproteobacteria and five of the six <span class="hlt">sites</span> were positive for soxB in the DNA fraction. Bulk RNA was also extracted from the same <span class="hlt">sites</span> to examine in situ expression of soxB. Data from these analyses, along with quantification of the soxB gene abundance and expression using quantitative PCR, are currently being carried out. Together, this data set of soxB gene diversity, expression, and abundance along with geochemical data will allow us to quantitatively determine the functional dynamics of sulfide oxidation in the subseafloor at Axial Seamount. The molecular techniques developed in this project are also being applied to fluid samples collected from many of the same <span class="hlt">sites</span> at Axial following the recent 2011 eruption, as well as fluid samples collected from new snowblower <span class="hlt">vents</span> believed to be rich in sulfide-oxidizing bacteria.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5544120','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5544120"><span id="translatedtitle">Physiological characteristics of Thiomicrospira sp. strain L-12 isolated from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ruby, E.G.; Jannasch, H.W.</p> <p>1982-01-01</p> <p>Growth of the obligately chemolithotrophic Thiomicrospira sp. strain L-12, isolated from a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> at a depth of 2,550 m in the Galapagos Rift region, was optimal at pH 8 and required 200 mM Na/sup +/ and divalent ions (Ca/sup 2 +/ and Mg/sup 2 +/). The organism was microaerophilic and tolerated 300 ..mu..M sulfide without a decrease in the rate of CO/sub 2/ incorporation. Growth and CO/sub 2/ incorporation occurred within the temperature range of 10 to 35/sup 0/C, with both optimal at 25/sup 0/C. At the in situ pressure of 250 atm, the rate of CO/sub 2/ incorporation was reduced by 25% relative to that measured at 1 atm; it was entirely suppressed at 500 atm. The results of this physiological characterization suggest that Thiomicrospira sp. strain L-12 can be an active autotroph in the <span class="hlt">hydrothermal</span> environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://seismo.berkeley.edu/~manga/fontaine.pdf','EPRINT'); return false;" href="http://seismo.berkeley.edu/~manga/fontaine.pdf"><span id="translatedtitle">Permeability changes due to mineral diagenesis in fractured crust: implications for <span class="hlt">hydrothermal</span> circulation at</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Manga, Michael</p> <p></p> <p>is consistent with recent seismic data showing <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> located at seismologically active ridge segments. ß 2001 Elsevier Science B.V. All rights reserved. Keywords: <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>; convection. The discovery of <span class="hlt">vent</span> <span class="hlt">sites</span> discharging hot £uids is the best evidence of hot <span class="hlt">hydrothermal</span> activity at ridge cr</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.B43L..08B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.B43L..08B"><span id="translatedtitle">Isotopic Approaches to Allying Productivity and Sulfur Metabolism in Three Symbiotic <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Molluscs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Beinart, R.; Gartman, A.; Sanders, J. G.; Luther, G. W.; Girguis, P. R.</p> <p>2012-12-01</p> <p>Symbioses between animals and chemosynthetic bacteria predominate at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. In these associations, the endosymbiotic bacteria utilize chemical reductants for the energy to support autotrophy, providing primary nutrition for the host. Despite their ubiquity at <span class="hlt">vents</span> worldwide, little is known about the rates of productivity of these symbioses under different physico-chemical regimes or how their metabolism effects the local geochemical environment. To address this matter, we used high-pressure flow through incubations and stable isotopic tracers to maintain three genera of symbiotic mollusc - the gastropods Alviniconcha and Ifremeria, and the mussel Bathymodiolus - at <span class="hlt">vent</span>-like conditions. Via the incorporation of isotopically labeled compounds, we assessed their productivity when using different reduced sulfur species as reductants. Using cyclic voltammetry, mass spectrometry and discrete geochemical analyses, we concurrently measured their effect on sulfur flux from the vessels. We found that the symbionts of all three genera can support autotrophy with hydrogen sulfide and thiosulfate, though at different rates. Additionally, by examining the rate of isotopic incorporation into biomass, we revealed intra-generic variability in productivity among the individuals in our experimental assemblages that are likely related to differences in the geochemical regime along the length of reactor. These geochemical gradients are due to the activity of other individuals within the vessel, since those organisms closest to the influent of the <span class="hlt">vent</span>-like water had the highest measured carbon incorporation. Finally, we measured the uptake and excretion of sulfur species, which illustrate the degree to which these symbioses might impact local sulfur chemistry in situ. These experiments show that A) access to particular sulfur species differentially affects the productivity of <span class="hlt">vent</span> symbioses, suggesting that competition for these substrates, both within and between host genera, could play a role in the structure of these communities, and B) that these symbioses could play a role in altering the local geochemical regime, influencing the activity and distribution of other associated microorganisms including free-living bacteria.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.V72A1285P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.V72A1285P"><span id="translatedtitle">Impact of the Colonization by Paralvinella sulfincola on the Microbial Diversity Associated with a Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Sulfide Chimney (Axial Seamount, Juan de Fuca Ridge)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Page, A.; Juniper, K.; Olagnon, M.; Alain, K.; Desrosiers, G.; Querellou, J.; Cambon-Bonavita, M.</p> <p>2002-12-01</p> <p>In the early stages of high temperature deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimneys growth, the walls remain porous and allow the escape of <span class="hlt">hydrothermal</span> fluids as well as an inflow of seawater. This gradual mixing creates sharp thermal and geochemical gradients and provides potential habitats for physiologically diverse microorganisms. The annelid polychaete Paralvinella sulfincola colonizes the external surfaces of these structures, covering them with layered mucous tubes that locally alter the mixing of discharged <span class="hlt">hydrothermal</span> fluids and surrounding seawater. Modifications of the physical and chemical conditions combined with an accumulation of elemental sulfur (S0) in P. sulfincola mucous tube are thought to be responsible for the deposition of a thin marcassite (FeS2) crust on outer surfaces of anhydrite chimneys (Juniper et al. 1992). This marcassite deposition could partly be induced by a shift in the composition of microbial communities that would to be locally associated with the presence of P. sulfincola. To test this hypothesis, we evaluated the impact of the colonization by P. sulfincola on the microbial communities present at the surface of an active sulfide chimney. Bacterial and archaeal 16S rRNA genes were amplified from DNA extracted from a P. sulfincola tube and from a chimney mineral sample. Using the statistical analysis demonstrated by Singleton et al. (2001), both clone libraries from the chimney sample have been shown to be significantly different from those of the P. sulfincola tube sample, even though the major phylogenetic groups of these libraries were similar. As it has been observed at other deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span>, the Epsilon-Proteobacteria and the Deep-sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Euryarchaeotic Group 1 were the dominant components of both bacterial and archaeal clone libraries. These results seem to indicate that P. sulfincola affect the microbial community composition on high temperature chimneys.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70033459','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70033459"><span id="translatedtitle">Deposition of talc - kerolite-smectite - smectite at seafloor <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields: Evidence from mineralogical, geochemical and oxygen isotope studies</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Dekov, V.M.; Cuadros, J.; Shanks, Wayne C.; Koski, R.A.</p> <p>2008-01-01</p> <p>Talc, kerolite-smectite, smectite, chlorite-smectite and chlorite samples from sediments, chimneys and massive sulfides from six seafloor <span class="hlt">hydrothermal</span> areas have been analyzed for mineralogy, chemistry and oxygen isotopes. Samples are from both peridotite- and basalt-hosted <span class="hlt">hydrothermal</span> systems, and basaltic systems include sediment-free and sediment-covered <span class="hlt">sites</span>. Mg-phyllosilicates at seafloor <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> have previously been described as talc, stevensite or saponite. In contrast, new data show tri-octahedral Mg-phyllosilicates ranging from pure talc and Fe-rich talc, through kerolite-rich kerolite-smectite to smectite-rich kerolite-smectite and tri-octahedral smectite. The most common occurrence is mixed-layer kerolite-smectite, which shows an almost complete interstratification series with 5 to 85% smectitic layers. The smectite interstratified with kerolite is mostly tri-octahedral. The degree of crystal perfection of the clay sequence decreases generally from talc to kerolite-smectite with lower crystalline perfection as the proportion of smectite layers in kerolite-smectite increases. Our studies do not support any dependence of the precipitated minerals on the type/subtype of <span class="hlt">hydrothermal</span> system. Oxygen isotope geothermometry demonstrates that talc and kerolite-smectite precipitated in chimneys, massive sulfide mounds, at the sediment surface and in open cracks in the sediment near seafloor are high-temperature (> 250????C) phases that are most probably the result of focused fluid discharge. The other end-member of this tri-octahedral Mg-phyllosilicate sequence, smectite, is a moderate-temperature (200-250????C) phase forming deep within the sediment (??? 0.8??m). Chlorite and chlorite-smectite, which constitute the alteration sediment matrix around the <span class="hlt">hydrothermal</span> mounds, are lower-temperature (150-200????C) phases produced by diffuse fluid discharge through the sediment around the <span class="hlt">hydrothermal</span> conduits. In addition to temperature, other two controls on the precipitation of this sequence are the silica activity and Mg/Al ratio (i.e. the degree of mixing of seawater with <span class="hlt">hydrothermal</span> fluid). Higher silica activity favors the formation of talc relative to tri-octahedral smectite. <span class="hlt">Vent</span> structures and sedimentary cover preclude complete mixing of <span class="hlt">hydrothermal</span> fluid and ambient seawater, resulting in lower Mg/Al ratios in the interior parts of the chimneys and deeper in the sediment which leads to the precipitation of phyllosilicates with lower Mg contents. Talc and kerolite-smectite have very low trace- and rare earth element contents. Some exhibit a negative or flat Eu anomaly, which suggests Eu depletion in the original <span class="hlt">hydrothermal</span> fluid. Such Eu depletion could be caused by precipitation of anhydrite or barite (sinks for Eu2+) deeper in the system. REE abundances and distribution patterns indicate that chlorite and chlorite-smectite are <span class="hlt">hydrothermal</span> alteration products of the background turbiditic sediment. ?? 2007 Elsevier B.V. All rights reserved.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.V11E..03C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.V11E..03C"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">Venting</span> at Kick'Em Jenny Submarine Volcano (West Indies)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carey, S.; Croff Bell, K. L.; Dondin, F. J. Y.; Roman, C.; Smart, C.; Lilley, M. D.; Lupton, J. E.; Ballard, R. D.</p> <p>2014-12-01</p> <p>Kick'em Jenny is a frequently-erupting, shallow submarine volcano located ~8 km off the northwest coast of Grenada in the West Indies. The last eruption took place in 2001 but did not breach the sea surface. Focused and diffuse <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> is taking place mainly within a small (~100 x 100 m) depression within the 300 m diameter crater of the volcano at depths of about 265 meters. Near the center of the depression clear fluids are being discharged from a focused mound-like <span class="hlt">vent</span> at a maximum temperature of 180o C with the simultaneous discharge of numerous bubble streams. The gas consists of 93-96% CO2 with trace amounts of methane and hydrogen. A sulfur component likely contributes 1-4% of the gas total. Gas flux measurements on individual bubble streams ranged from 10 to 100 kg of CO2 per day. Diffuse <span class="hlt">venting</span> with temperatures 5 to 35o C above ambient occurs throughout the depression and over large areas of the main crater. These zones are extensively colonized by reddish-yellow bacterial mats with the production of loose Fe-oxyhydroxides largely as a surface coating and in some cases, as fragile spires up to several meters in height. A high-resolution photo mosaic of the crater depression was constructed using the remotely operated vehicle Hercules on cruise NA039 of the E/V Nautilus. The image revealed prominent fluid flow patterns descending the sides of the depression towards the base. We speculate that the negatively buoyant fluid flow may be the result of second boiling of <span class="hlt">hydrothermal</span> fluids at Kick'em Jenny generating a dense saline component that does not rise despite its elevated temperature. Increased density may also be the result of high dissolved CO2 content of the fluids, although we were not able to measure this directly. The low amount of sulphide mineralization on the crater floor suggests that deposition may be occurring mostly subsurface, in accord with models of second boiling mineralization from other <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DSRII.121...53Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DSRII.121...53Z"><span id="translatedtitle">Intergradation between discrete lineages of Tevnia jerichonana, a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Haibin; Johnson, Shannon B.; Flores, Vanessa R.; Vrijenhoek, Robert C.</p> <p>2015-11-01</p> <p>We describe a broad zone of intergradation between genetically differentiated, northern and southern lineages of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworm, Tevnia jerichonana. DNA sequences from four genes, nuclear HSP and ATPs? and mitochondrial COI and Cytb were examined in samples from eastern Pacific <span class="hlt">vent</span> localities between 13°N and 38°S latitude. Allelic frequencies at these loci exhibited concordant latitudinal clines, and genetic differentiation (pairwise ?ST's) increased with geographical distances between sample localities. Though this pattern of differentiation suggested isolation-by-distance (IBD), it appeared to result from hierarchical population structure. Genotypic assignment tests identified two population clusters comprised of samples from the northern East Pacific Rise (NEPR: 9-13°N) and an extension of the Pacific-Antarctic Ridge (PAR: 31-32°S) with a zone of intergradation along the southern East Pacific Rise (SEPR: 7-17°S). The overall degrees of DNA sequence divergence between the NEPR and PAR populations were slight and not indicative of lengthy isolation. Bayesian assignment methods suggested that the SEPR populations constitute intergrades that connect the NEPR and PAR populations. Though it typically is difficult to distinguish between primary and secondary intergradation, our results were consistent with parallel studies of <span class="hlt">vent</span>-restricted species that suggest a high degree of demographic instability along the superfast-spreading SEPR axis. Frequent local extinctions and immigration from NEPR and PAR refugia probably shaped the observed pattern of intergradation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70034843','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70034843"><span id="translatedtitle">Genetic diversity and demographic instability in Riftia pachyptila tubeworms from eastern Pacific <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Coykendall, D.K.; Johnson, S.B.; Karl, S.A.; Lutz, R.A.; Vrijenhoek, R.C.</p> <p>2011-01-01</p> <p>Background: Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> animals occupy patchy and ephemeral habitats supported by chemosynthetic primary production. Volcanic and tectonic activities controlling the turnover of these habitats contribute to demographic instability that erodes genetic variation within and among colonies of these animals. We examined DNA sequences from one mitochondrial and three nuclear gene loci to assess genetic diversity in the siboglinid tubeworm, Riftia pachyptila, a widely distributed constituent of <span class="hlt">vents</span> along the East Pacific Rise and Galpagos Rift. Results: Genetic differentiation (FST) among populations increased with geographical distances, as expected under a linear stepping-stone model of dispersal. Low levels of DNA sequence diversity occurred at all four loci, allowing us to exclude the hypothesis that an idiosyncratic selective sweep eliminated mitochondrial diversity alone. Total gene diversity declined with tectonic spreading rates. The southernmost populations, which are subjected to superfast spreading rates and high probabilities of extinction, are relatively homogenous genetically. Conclusions: Compared to other <span class="hlt">vent</span> species, DNA sequence diversity is extremely low in R. pachyptila. Though its dispersal abilities appear to be effective, the low diversity, particularly in southern hemisphere populations, is consistent with frequent local extinction and (re)colonization events. ?? 2011 Coykendall et al; licensee BioMed Central Ltd.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015E%26PSL.424..245L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015E%26PSL.424..245L"><span id="translatedtitle">Subsurface conditions in <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> inferred from diffuse flow composition, and models of reaction and transport</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Larson, B. I.; Houghton, J. L.; Lowell, R. P.; Farough, A.; Meile, C. D.</p> <p>2015-08-01</p> <p>Chemical gradients in the subsurface of mid-ocean ridge <span class="hlt">hydrothermal</span> systems create an environment where minerals precipitate and dissolve and where chemosynthetic organisms thrive. However, owing to the lack of easy access to the subsurface, robust knowledge of the nature and extent of chemical transformations remains elusive. Here, we combine measurements of <span class="hlt">vent</span> fluid chemistry with geochemical and transport modeling to give new insights into the under-sampled subsurface. Temperature-composition relationships from a geochemical mixing model are superimposed on the subsurface temperature distribution determined using a heat flow model to estimate the spatial distribution of fluid composition. We then estimate the distribution of Gibb's free energies of reaction beneath mid oceanic ridges and by combining flow simulations with speciation calculations estimate anhydrite deposition rates. Applied to <span class="hlt">vent</span> endmembers observed at the fast spreading ridge at the East Pacific Rise, our results suggest that sealing times due to anhydrite formation are longer than the typical time between tectonic and magmatic events. The chemical composition of the neighboring low temperature flow indicates relatively uniform energetically favorable conditions for commonly inferred microbial processes such as methanogenesis, sulfate reduction and numerous oxidation reactions, suggesting that factors other than energy availability may control subsurface microbial biomass distribution. Thus, these model simulations complement fluid-sample datasets from surface <span class="hlt">venting</span> and help infer the chemical distribution and transformations in subsurface flow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1087270','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1087270"><span id="translatedtitle">Characterizing Microbial Community and Geochemical Dynamics at <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> Using Osmotically Driven Continuous Fluid Samplers</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Robidart, Julie C.; Callister, Stephen J.; Song, Peng F.; Nicora, Carrie D.; Wheat, Charles G.; Girguis, Peter R.</p> <p>2013-05-07</p> <p>Microbes play a key role in mediating all aquatic biogeochemical cycles, and ongoing efforts are aimed at better understanding the relationships between microbial phylogenetic and physiological diversity, and habitat physical and chemical characteristics. Establishing such relationships is facilitated by sampling and studying microbiology and geochemistry at the appropriate spatial and temporal scales, to access information on the past and current environmental state that contributes to observed microbial abundances and activities. A modest number of sampling systems exist to date, few of which can be used in remote, harsh environments such as <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, where the ephemeral nature of <span class="hlt">venting</span> underscores the necessity for higher resolution sampling. We have developed a robust, continuous fluid sampling system for co-registered microbial and biogeochemical analyses. The osmosis-powered bio-osmosampling system (BOSS) use no electricity, collects fluids with daily resolution or better, can be deployed in harsh, inaccessible environments and can sample fluids continuously for up to five years. Here we present a series of tests to examine DNA, RNA and protein stability over time, as well as material compatability, via lab experiments. We also conducted two field deployments at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> to assess changes in microbial diversity and protein expression as a function of the physico-chemical environment. Our data reveal significant changes in microbial community composition co-occurring with relatively modest changes in the geochemistry. These data additionally provide new insights into the distribution of an enigmatic sulfur oxidizing symbiont in its free-living state. Data from the second deployment reveal differences in the representation of peptides over time, underscoring the utility of the BOSS in meta-proteomic studies. In concert, these data demonstrate the efficacy of this approach, and illustrate the value of using this method to study microbial and geochemical phenomena.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24725254','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24725254"><span id="translatedtitle">Barite in <span class="hlt">hydrothermal</span> environments as a recorder of subseafloor processes: a multiple-isotope study from the Loki's Castle <span class="hlt">vent</span> field.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Eickmann, B; Thorseth, I H; Peters, M; Strauss, H; Bröcker, M; Pedersen, R B</p> <p>2014-07-01</p> <p>Barite chimneys are known to form in <span class="hlt">hydrothermal</span> systems where barium-enriched fluids generated by leaching of the oceanic basement are discharged and react with seawater sulfate. They also form at cold seeps along continental margins, where marine (or pelagic) barite in the sediments is remobilized because of subseafloor microbial sulfate reduction. We test the possibility of using multiple sulfur isotopes (?34S, ?33S, ?36S) of barite to identify microbial sulfate reduction in a <span class="hlt">hydrothermal</span> system. In addition to multiple sulfur isotopes, we present oxygen (?18O) and strontium (87Sr/86Sr) isotopes for one of numerous barite chimneys in a low-temperature (~20 °C) <span class="hlt">venting</span> area of the Loki's Castle black smoker field at the ultraslow-spreading Arctic Mid-Ocean Ridge (AMOR). The chemistry of the <span class="hlt">venting</span> fluids in the barite field identifies a contribution of at least 10% of high-temperature black smoker fluid, which is corroborated by 87Sr/86 Sr ratios in the barite chimney that are less radiogenic than in seawater. In contrast, oxygen and multiple sulfur isotopes indicate that the fluid from which the barite precipitated contained residual sulfate that was affected by microbial sulfate reduction. A sulfate reduction zone at this <span class="hlt">site</span> is further supported by the multiple sulfur isotopic composition of framboidal pyrite in the flow channel of the barite chimney and in the <span class="hlt">hydrothermal</span> sediments in the barite field, as well as by low SO4 and elevated H2S concentrations in the <span class="hlt">venting</span> fluids compared with conservative mixing values. We suggest that the mixing of ascending H2- and CH4-rich high-temperature fluids with percolating seawater fuels microbial sulfate reduction, which is subsequently recorded by barite formed at the seafloor in areas where the flow rate is sufficient. Thus, low-temperature precipitates in <span class="hlt">hydrothermal</span> systems are promising <span class="hlt">sites</span> to explore the interactions between the geosphere and biosphere in order to evaluate the microbial impact on these systems. PMID:24725254</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015HMR....69..343T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015HMR....69..343T"><span id="translatedtitle">Free-living nematode species (Nematoda) dwelling in <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> of the North Mid-Atlantic Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tchesunov, Alexei V.</p> <p>2015-12-01</p> <p>Morphological descriptions of seven free-living nematode species from <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> of the Mid-Atlantic Ridge are presented. Four of them are new for science: Paracanthonchus olgae sp. n. (Chromadorida, Cyatholaimidae), Prochromadora helenae sp. n. (Chromadorida, Chromadoridae), Prochaetosoma ventriverruca sp. n. (Desmodorida, Draconematidae) and Leptolaimus hydrothermalis sp. n. (Plectida, Leptolaimidae). Two species have been previously recorded in <span class="hlt">hydrothermal</span> habitats, and one species is recorded for the first time in such an environment. Oncholaimus scanicus (Enoplida, Oncholaimidae) was formerly known from only the type locality in non-<span class="hlt">hydrothermal</span> shallow milieu of the Norway Sea. O. scanicus is a very abundant species in Menez Gwen, Lucky Strike and Lost City <span class="hlt">hydrothermal</span> <span class="hlt">sites</span>, and population of the last locality differs from other two in some morphometric characteristics. Desmodora marci (Desmodorida, Desmodoridae) was previously known from other remote deep-sea <span class="hlt">hydrothermal</span> localities in south-western and north-eastern Pacific. Halomonhystera vandoverae (Monhysterida, Monhysteridae) was described and repeatedly found in mass in Snake Pit <span class="hlt">hydrothermal</span> <span class="hlt">site</span>. The whole <span class="hlt">hydrothermal</span> nematode assemblages are featured by low diversity in comparison with either shelf or deep-sea non-<span class="hlt">hydrothermal</span> communities. The nematode species list of the Atlantic <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> consists of representatives of common shallow-water genera; the new species are also related to some shelf species. On the average, the <span class="hlt">hydrothermal</span> species differ from those of slope and abyssal plains of comparable depths by larger sizes, diversity of buccal structures, presence of food content in the gut and ripe eggs in uteri.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4683240','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4683240"><span id="translatedtitle">Draft Genome Sequence of Caloranaerobacter sp. TR13, an Anaerobic Thermophilic Bacterium Isolated from a Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Xie, Yunbiao; Dong, Binbin; Liu, Qing; Chen, Xiaoyao</p> <p>2015-01-01</p> <p>Here, we report the draft 2,261,881-bp genome sequence of Caloranaerobacter sp. TR13, isolated from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> on the East Pacific Rise. The sequence will be helpful for understanding the genetic and metabolic features, as well as potential biotechnological application in the genus Caloranaerobacter. PMID:26679595</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://kuscholarworks.ku.edu/handle/1808/6041','EPRINT'); return false;" href="http://kuscholarworks.ku.edu/handle/1808/6041"><span id="translatedtitle">*Maractis rimicarivora*, a new genus and species of sea anemone (Cnidaria: Anthozoa: Actiniaria: Actinostolidae) from an Atlantic <span class="hlt">hydrothermal</span> <span class="hlt">vent</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Fautin, Daphne G.; Barber, Brian R.</p> <p>1999-01-01</p> <p>*Maractis rimicarivora* is a new genus and new species of medium-sized sea anemone (Actiniaria) from the TAG (Trans-Atlantic Geotraverse) <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields (26°08.3'N, 44°49.6'W; 3650 m). The genus, which belongs to family Actinostolidae...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeCoA.163...59S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeCoA.163...59S"><span id="translatedtitle">The Lost City <span class="hlt">hydrothermal</span> system: Constraints imposed by <span class="hlt">vent</span> fluid chemistry and reaction path models on subseafloor heat and mass transfer processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Seyfried, W. E.; Pester, Nicholas J.; Tutolo, Benjamin M.; Ding, Kang</p> <p>2015-08-01</p> <p>Since the first reported discovery of the Lost City <span class="hlt">hydrothermal</span> system in 2001, it was recognized that seawater alteration of ultramafic rocks plays a key role in the composition of the coexisting <span class="hlt">vent</span> fluids. The unusually high pH and high concentrations of H2 and CH4 provide compelling evidence for this. Here we report the chemistry of <span class="hlt">hydrothermal</span> fluids sampled from two <span class="hlt">vent</span> structures (Beehive: ?90-116 °C, and M6: ?75 °C) at Lost City in 2008 during cruise KNOX18RR using ROV Jason 2 and R/V Revelle assets. The <span class="hlt">vent</span> fluid chemistry at both <span class="hlt">sites</span> reveals considerable overlap in concentrations of dissolved gases (H2, CH4), trace elements (Cs, Rb, Li, B and Sr), and major elements (SO4, Ca, K, Na, Cl), including a surprising decrease in dissolved Cl, suggesting a common source fluid is feeding both <span class="hlt">sites</span>. The absence of Mg and relatively high concentrations of Ca and sulfate suggest solubility control by serpentine-diopside-anhydrite, while trace alkali concentrations, especially Rb and Cs, are high, assuming a depleted mantle protolith. In both cases, but especially for Beehive <span class="hlt">vent</span> fluid, the silica concentrations are well in excess of those expected for peridotite alteration and the coexistence of serpentine-brucite at all reasonable temperatures. However, both the measured pH and silica values are in better agreement with serpentine-diopside-tremolite-equilibria. Geochemical modeling demonstrates that reaction of plagioclase with serpentinized peridotite can shift the chemical system away from brucite and into the tremolite stability field. This is consistent with the complex intermingling of peridotite and gabbroic bodies commonly observed within the Atlantis Massif. We speculate the existence of such plagioclase bearing peridotite may also account for the highly enriched trace alkali (Cs, Rb) concentrations in the Lost City <span class="hlt">vent</span> fluids. Additionally, reactive transport modeling taking explicit account of temperature dependent rates of mineral dissolution and precipitation clarifies the feedback between permeability, heat loss, and changes in the dissolved Si of the <span class="hlt">vent</span> fluids. Assuming both the Beehive and M6 <span class="hlt">vent</span> fluids were sourced at similar subseafloor conditions (tremolite buffered at 200 °C), model results indicate loss of approximately 30% Si upon cooling to ?150 °C during upflow. However, Si concentrations remained largely conservative with continued cooling to lower temperatures owing to unfavorable reaction kinetics. While consistent with the Beehive endmember composition, these results fail to explain the relative Si depletion in the lower temperature M6 fluids. Thus, it may be that more robust kinetic models for silicates are needed to accurately account for the mechanism and rate of silica removal in the unusually high pH of the Lost City <span class="hlt">vent</span> fluids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.V41B1395M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.V41B1395M"><span id="translatedtitle">Quantitative Population Analysis of Some Groups of Epsilon-Proteobacteria, Using in situ Growth Chamber Samples From <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> in the South Mariana</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miyako, C.; Higashi, Y.; Maruyama, A.</p> <p>2004-12-01</p> <p>To reveal deep-sea <span class="hlt">hydrothermal</span> microbial ecosystems, we have developed and applied several new sampling systems, e.g., in situ filter samplers and in situ growth chambers. The later enables to incubate and accumulate microbes inside a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> with complex physico-chemical gradients naturally created in a <span class="hlt">vent</span> flow. Using this system, we have found several novel phylotypes of microbes in the Suiyo Seamount. Among them, two novel groups of epsilon-Proteobacteria (SSSV-BE1 and SSSV-BE2; Higashi et al. FEMS-ME 2004) were assumed to originate from sub-<span class="hlt">vent</span> fields, mainly at the borehole SH-APSK05. Some of the known epsilon groups, i.e., CorreOs Groups D (the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> type) and Group B (the microbial mat type), were also detected in the same samples. Afterwards, we have further improved in situ growth chambers larger to gain enough amounts of microbial RNA samples for quantitative population analyses. A new chamber system named column-II type was then applied to a natural <span class="hlt">vent</span> at Fryer <span class="hlt">site</span> in the Mariana Trough, with temperatures of <span class="hlt">venting</span> fluids beyond 109 C. Through the 16S rRNA gene clone library analysis, members of the above epsilon-Proteobacteria groups were frequently found in this column-II chamber sample, as well as the Suiyo Seamout samples. So, we tried to estimate population sizes of these epsilons by a quantitative fluorescent dot-blot hybridization (FDBH) technique. First, we newly designed two novel oligonucleotide probes specific to members of the groups D (26 mer) and SSSV-BE1 (23 mer), in which the stringency was checked using soft wares from Ribosomal Database Project II and DDBJ. Total RNA samples, after extracted and purified from the chamber samples, were applied to a nylon membrane filter and hybridized with these two specific probes, as well as Eubacteria, Universal, and some sub-domain/group-specific probes. After the hybridization, resulting fluorescence intensities were quantified, averaged, and compared each other, and then the target microbial population was calculated. Finally, we estimated the relative abundance of these epsilon-Proteobacteria groups in the total Bacteria, and the results implied that more SSSV-BE and group D exist as it goes to the deeper sub-<span class="hlt">vent</span>. Further examinations of the population, and of whether this phenomenon can be observed commonly such as from the Suiyo Seamount samples, are carried out at the moment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/11449263','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/11449263"><span id="translatedtitle">An off-axis <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field near the Mid-Atlantic Ridge at 30 degrees N.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kelley, D S; Karson, J A; Blackman, D K; Früh-Green, G L; Butterfield, D A; Lilley, M D; Olson, E J; Schrenk, M O; Roe, K K; Lebon, G T; Rivizzigno, P</p> <p>2001-07-12</p> <p>Evidence is growing that <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> occurs not only along mid-ocean ridges but also on old regions of the oceanic crust away from spreading centres. Here we report the discovery of an extensive <span class="hlt">hydrothermal</span> field at 30 degrees N near the eastern intersection of the Mid-Atlantic Ridge and the Atlantis fracture zone. The <span class="hlt">vent</span> field--named 'Lost City'--is distinctly different from all other known sea-floor <span class="hlt">hydrothermal</span> fields in that it is located on 1.5-Myr-old crust, nearly 15 km from the spreading axis, and may be driven by the heat of exothermic serpentinization reactions between sea water and mantle rocks. It is located on a dome-like massif and is dominated by steep-sided carbonate chimneys, rather than the sulphide structures typical of 'black smoker' <span class="hlt">hydrothermal</span> fields. We found that <span class="hlt">vent</span> fluids are relatively cool (40-75 degrees C) and alkaline (pH 9.0-9.8), supporting dense microbial communities that include anaerobic thermophiles. Because the geological characteristics of the Atlantis massif are similar to numerous areas of old crust along the Mid-Atlantic, Indian and Arctic ridges, these results indicate that a much larger portion of the oceanic crust may support <span class="hlt">hydrothermal</span> activity and microbial life than previously thought. PMID:11449263</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS23E1276S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS23E1276S"><span id="translatedtitle">Model exploration of the processes governing iron scavenging and the strength of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> iron source</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sherman, E.; Moore, J. K.</p> <p>2014-12-01</p> <p>New parameterizations of iron scavenging and <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> sources have been explored using the Community Earth System Model - Biogeochemical Elemental Cycling Model (CESM-BEC). Implementation of different iron scavenging schemes help to better elucidate dominant removal processes controlling dissolved iron concentrations in the ocean. Inclusion of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> sources allows for a more comprehensive understanding of deep sea iron cycling. Scientific literature suggests that iron binding ligands are an important component of iron cycling in that they reduce iron losses to particle scavenging, and thus increase iron lifetime in the ocean. In this work, we explore three iron scavenging schemes: implicit ligands, explicit ligands at a fixed concentration, and dynamic explicit ligands. Dynamic explicit representation of iron-binding ligands has been included in the CESM-BEC to better understand the control ligands exert on dissolved iron concentrations. This scavenging scheme includes explicit ligands sources and sinks and dynamic cycling with iron. Ligand sources include remineralization of POC, DOC, and refractory DOC, with some reuse of ligands by phytoplankton. Ligand sinks include biological uptake, ligand degradation and particle scavenging. <span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> have been shown to be an important source for the deep-sea iron budget. In this work, we use new data from GEOTRACES campaigns that sampled along <span class="hlt">hydrothermal</span> ridges to better constrain the <span class="hlt">hydrothermal</span> iron source in the model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMOS22A..07S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMOS22A..07S"><span id="translatedtitle">Discovery of Nascent <span class="hlt">Vents</span> and Recent Colonization Associated with(Re)activated <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Fields by the GALREX 2011 Expedition on the Galápagos Rift</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shank, T. M.; Holden, J. F.; Herrera, S.; Munro, C.; Muric, T.; Lin, J.; Stuart, L.</p> <p>2011-12-01</p> <p>GALREX 2011 was a NOAA OER telepresence cruise that explored the diverse habitats and geologic settings of the deep Galápagos region. The expedition made12 Little Hercules ROV dives in July 2011.Abundant corals and a strong depth zonation of species (including deepwater coral communities) were found near 500 m depth on Paramount Seamount, likely influenced by past low sea level states, wave-cut terrace processes, and the historical presence of shallow reef structures. At fresh lava flows with associated (flocculent) <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> near 88° W, now known as Uka Pacha and Pegasus <span class="hlt">Vent</span> Fields, rocks were coated with white microbial mat and lacked sessile fauna, with few mobile fauna (e.g., bythograeid crabs, alvinocarid shrimp, polynoid worms, zoarcid fish, and dirivultid copepods). This suggests a recent creation of <span class="hlt">hydrothermal</span> habitats through volcanic eruptions and/or diking events, which may have taken place over a 15 km span separating the two <span class="hlt">vent</span> fields. The Rosebud <span class="hlt">vent</span> field at 86°W was not observed and may have been covered with lava since last visited in 2005. A <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field near 86°W was discovered that is one of the largest <span class="hlt">vent</span> fields known on the Rift (120m by 40m). Low-temperature <span class="hlt">vent</span> habitats were colonized by low numbers of tubeworms including Riftia, Oasisia, and a potential Tevnia species (the latter not previously observed on the Galapagos Rift). Patches of tubeworms were observed with individuals less than 2cm in length, and the relatively few large Riftia had tube lengths near 70cm long. Large numbers of small (< 3cm long) bathymodiolin mussels lined cracks and crevices throughout the active part of the field. Live clams, at least four species of gastropod limpets, three species of polynoid polychaetes, juvenile and adult alvinocarid shrimp, actinostolid anemones, and white microbial communities were observed on the underside and vertical surfaces of basalt rock surfaces. There were at least 13 species of <span class="hlt">vent</span>-endemic fauna. The active colonization was observed on relatively older basalt pillows and lobate lavas ringed by and amidst a large dead bed of Calyptogena clams (most with broken and dissolving shells greater than 25 cm in length, with a few of the same size living amongst the dissolving shells). Scattered pockets of living adult mussels were observed among these dead clams. The margins of the field were ringed with large numbers of dandelion siphonophores. This field, named Tempus Fugit <span class="hlt">Vent</span> Field, was once a massive clam bed (> 20 years old) and now, while hosting mature mussel communities and adult clams (> 2 years old), is being actively colonized by <span class="hlt">vent</span>-endemic fauna that can be considered to be recent arrivals and colonizers (less than a few months) at Galapagos <span class="hlt">vent</span> fields. These findings not only provide strong evidence of recent volcanic activity between 85° W and 88° W on the Galapagos Rift, but provide evidence that the rates of <span class="hlt">hydrothermal</span> habitat turnover via eruption, dike injection, or <span class="hlt">venting</span> cessation may be considerably higher than previously thought along the Galápagos Rift.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012GGG....13.AG14O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012GGG....13.AG14O"><span id="translatedtitle">Geological context and <span class="hlt">vents</span> morphology of the ultramafic-hosted Ashadze <span class="hlt">hydrothermal</span> areas (Mid-Atlantic Ridge 13°N)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>OndréAs, HéLèNe; Cannat, Mathilde; Fouquet, Yves; Normand, Alain</p> <p>2012-11-01</p> <p>Recent ROV dives and high-resolution bathymetric data acquired over the Ashadze fields on the Mid-Atlantic Ridge (13°N) allow us to derive constraints on the regional and local geological setting of ultramafic-hosted <span class="hlt">hydrothermal</span> fields. The active <span class="hlt">vent</span> fields of Ashadze <span class="hlt">hydrothermal</span> fields are located in the western axial valley wall, downslope from the termination of a prominent corrugated surface and in a transitional domain with respect to ridge segmentation. The study of the shipboard and ROV bathymetry shows that decameter (100 m by 60 m) to kilometer-scaled rockslides shape the axial valley wall slopes in this region. The Ashadze 1 <span class="hlt">vent</span> field occurs on a coherent granular landslide rock mass that is elongated in an E-W direction. The Ashadze 1 <span class="hlt">vent</span> field comprises hundreds of active and inactive sulfide chimneys. The Ashadze 2 <span class="hlt">vent</span> field is located in a NNE-trending linear depression which separates outcrops of gabbros and serpentinized peridotites. Active black smokers in the Ashadze 2 field are located on ultramafic substratum in a 40-m diameter crater, 5-m deep. This crater recalls similar structures described at some <span class="hlt">vents</span> of the Logatchev <span class="hlt">hydrothermal</span> field (Mid-Atlantic Ridge 15°N). We discuss the mode of formation for these craters, as well as that for a breadcrust-like array of radial fissures identified at Ashadze 1. We propose that <span class="hlt">hydrothermalism</span> at Ashadze can be an explosive phenomena associated with geyser-like explosions. Our study also constrains the geological and geophysical context of the ultramafic-hosted Ashadze <span class="hlt">hydrothermal</span> system that may use the oceanic detachment fault as a preferred permeability conduit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.T52B..07T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.T52B..07T"><span id="translatedtitle">First Discovery and Investigation of a High-Temperature <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Field on the Ultra- Slow Spreading Southwest Indian Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tao, C.; Lin, J.; Guo, S.; Chen, Y. J.; Wu, G.; Han, X.; German, C. R.; Yoerger, D. R.; Zhu, J.; Zhou, N.; Su, X.; Baker, E. T.; Party, S.</p> <p>2007-12-01</p> <p>Two recent cruises on board the Chinese research vessel Dayang Yihao have successfully investigated the first active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field to be located along the ultraslow spreading Southwest Indian Ridge (SWIR) and collected <span class="hlt">hydrothermal</span> sulfide deposit samples. The newly discovered <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field is located on the western end of a magmatically robust spreading segment immediately west of the Gallieni transform fault. Preliminary evidence of strong turbidity anomalies was first measured during a Nov. 2005 cruise on board Dayang Yihao (InterRidge News, vol. 15, pp. 33-34, 2006). Color video footages of the seafloor in the <span class="hlt">vent</span>-field area were first obtained by a deep-towed video camera in February 2007 during DY115-19 Leg 1, when significant water column turbidity anomalies, noticeable temperature anomalies and methane anomalies were also measured. The <span class="hlt">vent</span> field was then precisely located, mapped, and photographed in great detail in February- March 2007 during the DY115-19 Leg 2, using the autonomous underwater vehicle ABE of the Woods Hole Oceanographic Institution. A high-resolution bathymetric map, more than 5,000 near-bottom color photos, and several types of water column data were all obtained during three phases of ABE dives. Within the approximately 120-m-long by 100-m-wide <span class="hlt">hydrothermal</span> field, three groups of active high-temperature <span class="hlt">vents</span> were identified and color images of black smokers and associated biological communities were obtained from ABE, flying 5 m above the seafloor. <span class="hlt">Hydrothermal</span> sulfide deposits were then successfully obtained using a TV-guided grab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.T52B..07T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.T52B..07T"><span id="translatedtitle">First Discovery and Investigation of a High-Temperature <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Field on the Ultra- Slow Spreading Southwest Indian Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tao, C.; Lin, J.; Guo, S.; Chen, Y. J.; Wu, G.; Han, X.; German, C. R.; Yoerger, D. R.; Zhu, J.; Zhou, N.; Su, X.; Baker, E. T.; Party, S.</p> <p>2004-12-01</p> <p>Two recent cruises on board the Chinese research vessel Dayang Yihao have successfully investigated the first active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field to be located along the ultraslow spreading Southwest Indian Ridge (SWIR) and collected <span class="hlt">hydrothermal</span> sulfide deposit samples. The newly discovered <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field is located on the western end of a magmatically robust spreading segment immediately west of the Gallieni transform fault. Preliminary evidence of strong turbidity anomalies was first measured during a Nov. 2005 cruise on board Dayang Yihao (InterRidge News, vol. 15, pp. 33-34, 2006). Color video footages of the seafloor in the <span class="hlt">vent</span>-field area were first obtained by a deep-towed video camera in February 2007 during DY115-19 Leg 1, when significant water column turbidity anomalies, noticeable temperature anomalies and methane anomalies were also measured. The <span class="hlt">vent</span> field was then precisely located, mapped, and photographed in great detail in February- March 2007 during the DY115-19 Leg 2, using the autonomous underwater vehicle ABE of the Woods Hole Oceanographic Institution. A high-resolution bathymetric map, more than 5,000 near-bottom color photos, and several types of water column data were all obtained during three phases of ABE dives. Within the approximately 120-m-long by 100-m-wide <span class="hlt">hydrothermal</span> field, three groups of active high-temperature <span class="hlt">vents</span> were identified and color images of black smokers and associated biological communities were obtained from ABE, flying 5 m above the seafloor. <span class="hlt">Hydrothermal</span> sulfide deposits were then successfully obtained using a TV-guided grab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.P51A1393R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.P51A1393R"><span id="translatedtitle">The Oxygen Isotope Composition of PO4 Extracted From Lost City <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> -- a Potential Biosignature for <span class="hlt">Vent</span> Hosted Microbial Ecosystems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Robinson, K. L.; Kelley, D. S.; Fogel, M. L.; Colman, A. S.</p> <p>2008-12-01</p> <p>The oxygen isotope composition of phosphate is a useful indicator of biological P cycling in low to moderate temperature environments, such as those that characterize most of the habitable zone of Earth. In microbially active systems, phosphate oxygen isotope compositions are driven towards a temperature- dependent, thermodynamic equilibrium offset from water. Enzymatic reactions involving organophosphorus compounds, pyrophosphate, and polyphosphates promote the exchange of oxygen atoms between water and phosphate. These enzyme driven reactions are key to the attainment of isotopic equilibrium under conditions in which the rate of inorganic oxygen exchange is slow. We have examined the phosphate oxygen isotope systematics of the Lost City <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> system, which is located on a gabbroic and peridotitic massif, 15km off-axis of the Mid Atlantic Ridge. The Lost City <span class="hlt">hydrothermal</span> system's fluid chemistry and heat budget are controlled by serpentinization reactions. Fluids <span class="hlt">vent</span> at temperatures up to around 80°C and with a pH around 9-10. <span class="hlt">Vent</span> mineralogy is dominated by calcite, aragonite, and brucite, with mineral layers intercalated by biofilms. Phosphorus content ranges from 400 - 1000 ppm (by mass as P2O5) in the <span class="hlt">vent</span> samples we have analyzed. The oxygen isotope composition of phosphate extracted from the <span class="hlt">vent</span> solids is a few per mil lighter than that of phosphate dissolved in ambient sea water. This oxygen isotope composition reflects exchange of phosphate oxygen with water oxygen at elevated temperature. We show that under a wide range of conditions, abiological reaction rates are too slow to produce these isotopic compositions. This suggests that cycling of the phosphate by the <span class="hlt">vent</span> system's microbial community has imprinted the phosphate with a stable isotope signature of biological activity. The oxygen isotope composition of lattice-bound phosphate preserves well in the geologic record, commending phosphate oxygen isotope measurements as a tool for the detection of life in ancient terrestrial and in extraterrestrial rocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMOS41C1833S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMOS41C1833S"><span id="translatedtitle">In-Situ pH Measurements in Mid-Ocean Ridge <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Fluids: Constraints on Subseafloor Alteration Processes at Crustal Depths</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schaen, A. T.; Ding, K.; Seyfried, W. E.</p> <p>2013-12-01</p> <p>Developments in electrochemistry and material science have facilitated the construction of ceramic (YSZ) based chemical sensor systems that can be used to measure and monitor pH and redox in aqueous fluids at elevated temperatures and pressures. In recent years, these sensor systems have been deployed to acquire real-time and time series in-situ data for high-temperature <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids at the Main Endeavour Field (Juan de Fuca Ridge), 9oN (East Pacific Rise), and at the ultramafic-hosted Rainbow field (36oN, Mid-Atlantic Ridge). Here we review in-situ pH data measured at these <span class="hlt">sites</span> and apply these data to estimate the pH of fluids ascending to the seafloor from <span class="hlt">hydrothermal</span> alteration zones deeper in the crust. In general, in-situ pH measured at virtually all <span class="hlt">vent</span> <span class="hlt">sites</span> is well in excess of that measured shipboard owing to the effects of temperature on the distribution of aqueous species and the solubility of metal sulfides, especially Cu and Zn, originally dissolved in the <span class="hlt">vent</span> fluids. In situ pH measurements determined at MEF (Sully <span class="hlt">vent</span>) and EPR 9oN (P-<span class="hlt">vent</span>) in 2005 and 2008 were 4.4 ×0.02 and 5.05×0.05, respectively. The temperature and pressure (seafloor) of the <span class="hlt">vent</span> fluids at each of the respective <span class="hlt">sites</span> were 356oC and 220 bar, and 380oC and 250 bar. Plotting these data with respect to fluid density reveals that the in-situ pH of each <span class="hlt">vent</span> fluid is approximately 1.5 pH units below neutrality. The density-pH (in-situ) correlation, however, is important because it provides a means from which the <span class="hlt">vent</span> fluids were derived. Using dissolved silica and chloride from fluid samples at the MEF (Sully) suggest T/P conditions of approximately 435oC, 380 bar, based on quartz-fluid and NaCl-H2O systems. At the fluid density calculated for these conditions, pH (in-situ) is predicted to be ~6.2. Attempts are presently underway to assess the effect of the calculated pH on metal sulfide and silicate (e.g., plagioclase, chlorite) solubility in comparison with constraints imposed by the full range of chemical components in the <span class="hlt">vent</span> fluids sampled and analyzed in association with pH (in-situ) measurements. Since pH is a master variable in all geochemical systems, the novel approach proposed here may provide new insight on <span class="hlt">hydrothermal</span> alteration processes at conditions difficult or impossible to assess by more traditional means, ultimately influencing <span class="hlt">hydrothermal</span> fluid fluxes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4496463','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4496463"><span id="translatedtitle">Size matters at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>: different diversity and habitat fidelity patterns of meio- and macrofauna</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gollner, Sabine; Govenar, Breea; Fisher, Charles R.; Bright, Monika</p> <p>2015-01-01</p> <p>Species with markedly different sizes interact when sharing the same habitat. Unravelling mechanisms that control diversity thus requires consideration of a range of size classes. We compared patterns of diversity and community structure for meio- and macrofaunal communities sampled along a gradient of environmental stress at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the East Pacific Rise (9° 50? N) and neighboring basalt habitats. Both meio- and macrofaunal species richnesses were lowest in the high-stress <span class="hlt">vent</span> habitat, but macrofaunal richness was highest among intermediate-stress <span class="hlt">vent</span> habitats. Meiofaunal species richness was negatively correlated with stress, and highest on the basalt. In these deep-sea basalt habitats surrounding <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, meiofaunal species richness was consistently higher than that of macrofauna. Consideration of the physiological capabilities and life history traits of different-sized animals suggests that different patterns of diversity may be caused by different capabilities to deal with environmental stress in the 2 size classes. In contrast to meiofauna, adaptations of macrofauna may have evolved to allow them to maintain their physiological homeostasis in a variety of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> habitats and exploit this food-rich deep-sea environment in high abundances. The habitat fidelity patterns also differed: macrofaunal species occurred primarily at <span class="hlt">vents</span> and were generally restricted to this habitat, but meiofaunal species were distributed more evenly across proximate and distant basalt habitats and were thus not restricted to <span class="hlt">vent</span> habitats. Over evolutionary time scales these contrasting patterns are likely driven by distinct reproduction strategies and food demands inherent to fauna of different sizes. PMID:26166922</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://arxiv.org/pdf/1212.2271.pdf','EPRINT'); return false;" href="http://arxiv.org/pdf/1212.2271.pdf"><span id="translatedtitle">Major transitions in evolution linked to thermal gradients above <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Muller, Anthonie W J</p> <p>2012-01-01</p> <p>The emergence of the main divisions of today's life: (1) unicellular prokaryotes, (2) unicellular eukaryotes, (3) multicellular eukaryotes, and (4) metazoans, are examples of the--still unexplained--major transitions in evolution. Regarding the origin of life, I have proposed that primordial life functioned as heat engine (thermosynthesis) while thermally cycled in convecting volcanic hot springs. Here I argue for a role of thermal gradients above submarine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> (SHV) in several major transitions. The last decade has witnessed the emergence of phononics, a novel discipline in physics based on controlled heat transport in thermal gradients. It builds thermal analogs to electronic devices: the thermal diode, the thermal transistor, the thermal switch, the thermal amplifier, the thermal memory--the thermal computer has been proposed. Encouraged by (1) the many similarities between microtubules (MT) and carbon nanotubes, which have a very high thermal conductivity, and (2) the recent discovery of a ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004cosp...35.2180P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004cosp...35.2180P"><span id="translatedtitle">Borders of life: lessons from Microbiology of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prieur, D.</p> <p></p> <p>Thirty years ago, the deep-sea was known as a low density biotope due to coldness, darkness and famine-like conditions. The discovery of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the Eastern Pacific in 1977 and the associated black smokers in 1979 considerably changed our views about life on Earth. For the first time, an ecosystem almost independent (at least for tens of years) of solar nergy was discovered. Besides the spectacular and unexpected communities of invertebrates based on symbiotic associations with chemo-litho-autotrophic bacteria, prokaryotic communities associated with high temperature black smokers fascinated microbiologists of extreme environments. Within mineral structures where temperature gradients may fluctuate from ambient seawater temperatures (2°C) up to 350°C, thermophilic (optimal growth above 60°C) and hyperthermophilic (optimal growth above 80°C) microorganisms thrived under very severe conditions due to elevated hydrostatic pressure, toxic compounds or strong ionizing radiations. These organisms belong to both domains of Bacteria and Archaea and live aerobically but mostly anaerobically, using a variety of inorganic and organic carbon sources, and a variety of electron donnors and acceptors as well. The most thermophilic organism known on Earth was isolated from a mid-Atlantic-Ridge hydrotermal <span class="hlt">vent</span>: Pyrolobus fumarii grows optimally at 110°c and its upper temperature limit for life is 113°C. Such an organism survived to autoclaving conditions currently used for sterilization procedures. Many other hyperthermophilic organisms were isolated and described, including fermenters, sulphate and sulphur reducers, hydrogen oxidizers, nitrate reducers, methanogens, etc. Although most of anaerobes are killed when exposed to oxygen, several deep-sea hyperthermophiles appeared to survive to both oxygen and starvation exposures, indicating that they probably can colonize rather distant environments Because of elevated hydrostatic pressure that exists at deep-sea <span class="hlt">vents</span>, <span class="hlt">hydrothermal</span> fluids remain liquid at temperatures above 100°C (boiling water temperature under atmospheric pressure). If strictly barophilic thermophiles or hyperthermophiles have not been reported yet (the deepest <span class="hlt">vents</span> known are 3500 m in depth), barophilic Bacteria and Archaea have been reported that grow much more faster when exposed to in situ (pressurized) conditions. Morover, they grow preferentially at pressures above those existing at captures depth, that may indicate that their natural habitat is situated below the sea floor. Recently, several studies reported that hyperthermophiles and particularly deep-sea organisms may resist to elevated doses of gamma ionizing radiations, as strong as 20 kGy, similarly to the famous radioresistant bacterium Deinococcus radiodurans. From these reports, it can be concluded that exploration of Earth is not already finished: novel biotopes, novel organisms with novel metabolic and physiologic properties are waiting for their discovery. Also, severe physio-chemical conditions allow for florishing living forms that use efficiently chemical energy sources. If these data do not allow to claim that life arose at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, they clearly extend physio-chemical and spatial borders of life and stimulate to further exploration of Earth and the solar system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3721115','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3721115"><span id="translatedtitle">Metatranscriptomics reveal differences in in situ energy and nitrogen metabolism among <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> snail symbionts</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sanders, J G; Beinart, R A; Stewart, F J; Delong, E F; Girguis, P R</p> <p>2013-01-01</p> <p>Despite the ubiquity of chemoautotrophic symbioses at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, our understanding of the influence of environmental chemistry on symbiont metabolism is limited. Transcriptomic analyses are useful for linking physiological poise to environmental conditions, but recovering samples from the deep sea is challenging, as the long recovery times can change expression profiles before preservation. Here, we present a novel, in situ RNA sampling and preservation device, which we used to compare the symbiont metatranscriptomes associated with Alviniconcha, a genus of <span class="hlt">vent</span> snail, in which specific host–symbiont combinations are predictably distributed across a regional geochemical gradient. Metatranscriptomes of these symbionts reveal key differences in energy and nitrogen metabolism relating to both environmental chemistry (that is, the relative expression of genes) and symbiont phylogeny (that is, the specific pathways employed). Unexpectedly, dramatic differences in expression of transposases and flagellar genes suggest that different symbiont types may also have distinct life histories. These data further our understanding of these symbionts' metabolic capabilities and their expression in situ, and suggest an important role for symbionts in mediating their hosts' interaction with regional-scale differences in geochemistry. PMID:23619306</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003DSRI...50..269Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003DSRI...50..269Z"><span id="translatedtitle">Mineralogical gradients associated with alvinellids at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zbinden, Magali; Le Bris, Nadine; Compère, Philippe; Martinez, Isabelle; Guyot, François; Gaill, Françoise</p> <p>2003-02-01</p> <p>Alvinella pompejana and Alvinella caudata live in organic tubes on active sulphide chimney walls at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. These polychaete annelids are exposed to extreme thermal and chemical gradients and to intense mineral precipitation. This work points out that mineral particles associated with Pompeii worm ( A. pompejana and A. caudata) tubes constitute useful markers for evaluating the chemical characteristics of their micro-environment. The minerals associated with these worm tubes were analysed on samples recovered from an experimental alvinellid colony, at different locations in the <span class="hlt">vent</span> fluid-seawater interface. Inhabited tubes from the most upper and lower parts of the colony were analysed by light and electron microscopies, X-ray microanalysis and X-ray diffraction. A change was observed from a Fe-Zn-S mineral assemblage to a Zn-S assemblage at the millimeter scale from the outer to the inner face of a tube. A similar gradient in proportions of minerals was observed at a decimeter scale from the lower to the upper part of the colony. The marcasite/pyrite ratio of iron disulphides also displays a steep decrease along the few millimeters adjacent to the external tube surface. The occurrence of these gradients indicates that the micro-environment within the tube differs from that outside the tube, and suggests that the tube wall acts as an efficient barrier to the external environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5950250','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5950250"><span id="translatedtitle">Characterization of large, autotrophic Beggiatoa spp. abundant at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> of the Guaymas Basin</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Nelson, D.C. ); Wirsen, C.O.; Jannasch, H.W. )</p> <p>1989-11-01</p> <p>Filamentous bacteria, identified as members of the genus Beggiatoa by gliding motility and internal globules of elemental sulfur, occur in massive aggregations at the deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> of the Guaymas Basin, Gulf of California. Cell aggregates covering the surface of sulfide-emanating sediments and rock chimneys were collected by DS R/V Alvin and subjected to shipboard and laboratory experiments. Each sample collected contained one to three discrete width classes of this organism usually accompanied by a small number of flexibacteria (width, 1.5 to 4 {mu}m). The average widths of the Beggiatoa classes were 24 to 32, 40 to 42, and 116 to 122 {mu}m. As indicated by electron microscopy and cell volume/protein ratios, the dominant bacteria are hollow cells, i.e., a thin layer of cytoplasm surrounding a large central liquid vacuole. Activities of Calvin-cycle enzymes indicated that at least two of the classes collected possess autotrophic potential. Judging from temperature dependence of enzyme activities and whole-cell CO{sub 2} incorporation, the widest cells were mesophiles. The narrowest Beggiatoa sp. was either moderately thermophilic or mesophilic with unusually thermotolerant enzymes. This was consistent with its occurrence on the flanks of hot smoker chimneys with highly variable exit temperatures. In situ CO{sub 2} fixation rates, sulfide stimulation of incorporation, and autoradiographic studies suggest that these Beggiatoa spp. contribute significantly as lithoautrophic primary producers to the Guaymas Basin <span class="hlt">vent</span> ecosystems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFMOS21C..04G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFMOS21C..04G"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> Activity on the Southern Mid-Atlantic Ridge: Tectonically- and Volcanically-Hosted High Temperature <span class="hlt">Venting</span> at 2-7 Degrees S</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>German, C. R.; Parson, L. M.; Murton, B. J.; Bennett, S. A.; Connelly, D. P.; Evans, A. J.; Prien, R. D.; Ramirez-Llodra, E. Z.; Shank, T. M.; Yoerger, D. R.; Jakuba, M.; Bradley, A. M.; Baker, E. T.; Nakamura, K.</p> <p>2005-12-01</p> <p>We have conducted a systematic investigation for <span class="hlt">hydrothermal</span> activity along the southern Mid-Atlantic Ridge, 2°30-6°50 S. Our initial approach was to use a combination of multi-beam swath mapping, deep-tow sidescan sonar imaging and water column plume-detection using MAPRs and CTD-rosette system to locate new <span class="hlt">sites</span> of <span class="hlt">hydrothermal</span> activity immediately south of the Romanche and Chain Fracture zones. We wanted to test whether these geologic features represent a significant barrier to gene-flow along-axis away from northern MAR <span class="hlt">vent</span> ecosystems. During the first leg of our research cruise (RRS Charles Darwin cruise CD169, Feb-Mar 2005) we used this approach to identify two <span class="hlt">hydrothermally</span> active regions, one in a non-transform discontinuity near 4°S and the other in a segment centre characterised by very fresh sheet-flows near 5°S. During Leg 2 we returned to the second of these areas and deployed ABE, WHOI's autonomous underwater vehicle, in a three-phase strategy to prospect for, locate, and image new <span class="hlt">hydrothermal</span> fields. During Phase 1 two discrete target areas were located ca. 1km apart along strike within the segment centre. During Phase 2 these two areas were each mapped in detail using an SM2000 system while in situ optical back scatter, Eh, temperature, Mn and Fe(II) sensors were used to confirm the interception of buoyant <span class="hlt">hydrothermal</span> plumes rising from the seafloor. Finally we redeployed ABE (Phase 3) to collect photo-mosaics of each of two new <span class="hlt">vent</span>-areas whilst simultaneously sampling their buoyant plumes by CTD-rosette for TDMn, Fe and CH4 analyses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.S13F..02W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.S13F..02W"><span id="translatedtitle">Microearthquakes Beneath the Endeavour <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Fields: Insights Into Reaction Zone Processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilcock, W. S.; Hooft, E. E.; McGill, P. R.; Toomey, D. R.; Barclay, A. H.; Stakes, D. S.; Ramirez, T. M.</p> <p>2007-12-01</p> <p>From 2003-2006, a novel seismic network comprising seven short-period corehole seismometers and a broadband Guralp CMG-1T OBS was deployed using remotely operated vehicles in a subseafloor configuration on the Endeavour segment of the Juan de Fuca mid-ocean ridge. The seismic monitoring array was one part of a multi-disciplinary prototype NEPTUNE experiment designed to investigate the linkages between seismic deformation, <span class="hlt">hydrothermal</span> fluxes, and microbial productivity along oceanic plate boundaries. The seismic network recorded high-quality data that illustrate the advantages of using an ROV to deploy seismometers in well- coupled configurations that are also away from the effects of ocean currents. A preliminary analysis of the first year of Keck seismic data was undertaken during a research apprenticeship class taught in the fall of 2004 at the University of Washington's Friday Harbor Laboratories. Eight post- baccalaureate students obtained a preliminary catalog of nearly 13,000 earthquakes on the Endeavour segment. Two of the apprentices conducted a second-pass analysis to refine the locations of ~3000 earthquakes that are within or near the network. Further analysis of these proximal earthquakes has focused on the application of cross-correlation and relative relocation techniques, the determination of focal mechanisms using P-wave first motions and P- to S-wave amplitudes ratios, and improved estimates of earthquake magnitudes. The results show that the entire Endeavour segment was seismically active during 2003-2004. Within the network, the earthquakes are located in tight clusters centered at ~2 km depth in the inferred location of the <span class="hlt">hydrothermal</span> reaction zone immediately above a crustal magma chamber imaged by seismic reflection studies. The number of earthquakes below each <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field correlates with the heat flux measured by other researchers and the vertical thickness of this reaction zone, inferred from the distribution of seismicity, is ~0.5-1 km. Preliminary focal mechanisms show a transition from ridge-perpendicular extension beneath the rise axis to ridge-perpendicular compression on either side over horizontal distances of <1 km. This is most simply explained if the stress field above the magma chamber is locally influenced by either the injection of magma or over-pressured <span class="hlt">hydrothermal</span> fluids. This observation, in combination with a reaction zone thickness that is at least an order of magnitude larger than that inferred from thermal boundary layer theory, suggests that the heat transfer between the magmatic and <span class="hlt">hydrothermal</span> systems is not simply the result of cold water attacking hot magma. Instead, it appears as though the magmatic system also attacks the reaction zone from below.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.V21A4705E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.V21A4705E"><span id="translatedtitle">Gas Chemistry of Submarine <span class="hlt">Hydrothermal</span> <span class="hlt">Venting</span> at Maug Caldera, Mariana Arc</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Embley, R. W.; Lupton, J. E.; Butterfield, D. A.; Lilley, M. D.; Evans, L. J.; Olson, E. J.; Resing, J. A.; Buck, N.; Larson, B. I.; Young, C.</p> <p>2014-12-01</p> <p>Maug volcano consists of 3 islands that define the perimeter of a submerged caldera that was formed by an explosive eruption. The caldera reaches a depth of ~225 meters, and has a prominent central cone or pinnacle that ascends within 20 meters of the sea surface. Our exploration of Maug began in 2003, when a single hydrocast in the caldera detected a strong suspended particle and helium plume reaching a maximum of ?3He = 250% at ~180 meters depth, clearly indicating <span class="hlt">hydrothermal</span> activity within the caldera. In 2004 we returned armed with the ROPOS ROV, and two ROPOS dives discovered and sampled low temperature (~4 °C) diffuse <span class="hlt">venting</span> associated with bacterial mats on the NE flank of the central pinnacle at 145 m depth. Samples collected with titanium gas tight bottles were badly diluted with ambient seawater but allowed an estimate of end-member 3He/4He of 7.3 Ra. Four vertical casts lowered into the caldera in 2004 all had a strong 3He signal (?3He = 190%) at 150-190 meters depth. A recent expedition in 2014 focused on the shallow (~10 m) gas <span class="hlt">venting</span> along the caldera interior. Scuba divers were able to collect samples of the gas bubbles using evacuated SS bottles fitted with plastic funnels. The gas samples had a consistent ~170 ppm He, 8 ppmNe, 60% CO2, 40%N2, and 0.8% Ar, and an end-member 3He/4He ratio of 6.9 Ra. This 3He/4He ratio falls within the range for typical arc volcanoes. The rather high atmospheric component (N2, Ar, Ne) in these samples is not contamination but appears to be derived from subsurface exchange between the ascending CO2 bubbles and air saturated seawater. A single vertical cast in 2014 had a maximum ?3He = 55% at 140 m depth, much lower than in 2003 and 2004. This decrease is possibly due to recent flushing of the caldera by a storm event, or may reflect a decrease in the deep <span class="hlt">hydrothermal</span> activity. This area of shallow CO2 <span class="hlt">venting</span> in Maug caldera is of particular interest as a natural laboratory for studying the effects of ocean acidification on corals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS52A..05B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS52A..05B"><span id="translatedtitle">Event Detection for <span class="hlt">Hydrothermal</span> Plumes: A case study at Grotto <span class="hlt">Vent</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bemis, K. G.; Ozer, S.; Xu, G.; Rona, P. A.; Silver, D.</p> <p>2012-12-01</p> <p>Evidence is mounting that geologic events such as volcanic eruptions (and intrusions) and earthquakes (near and far) influence the flow rates and temperatures of <span class="hlt">hydrothermal</span> systems. Connecting such suppositions to observations of <span class="hlt">hydrothermal</span> output is challenging, but new ongoing time series have the potential to capture such events. This study explores using activity detection, a technique modified from computer vision, to identify pre-defined events within an extended time series recorded by COVIS (Cabled Observatory <span class="hlt">Vent</span> Imaging Sonar) and applies it to a time series, with gaps, from Sept 2010 to the present; available measurements include plume orientation, plume rise rate, and diffuse flow area at the NEPTUNE Canada Observatory at Grotto <span class="hlt">Vent</span>, Main Endeavour Field, Juan de Fuca Ridge. Activity detection is the process of finding a pattern (activity) in a data set containing many different types of patterns. Among many approaches proposed to model and detect activities, we have chosen a graph-based technique, Petri Nets, as they do not require training data to model the activity. They use the domain expert's knowledge to build the activity as a combination of feature states and their transitions (actions). Starting from a conceptual model of how <span class="hlt">hydrothermal</span> plumes respond to daily tides, we have developed a Petri Net based detection algorithm that identifies deviations from the specified response. Initially we assumed that the orientation of the plume would change smoothly and symmetrically in a consistent daily pattern. However, results indicate that the rate of directional changes varies. The present Petri Net detects unusually large and rapid changes in direction or amount of bending; however inspection of Figure 1 suggests that many of the events detected may be artifacts resulting from gaps in the data or from the large temporal spacing. Still, considerable complexity overlies the "normal" tidal response pattern (the data has a dominant frequency of ~12.9 hours). We are in the process of defining several events of particular scientific interest: 1) transient behavioral changes associated with atmospheric storms, earthquakes or volcanic intrusions or eruptions, 2) mutual interaction of neighboring plumes on each other's behavior, and 3) rapid shifts in plume direction that indicate the presence of unusual currents or changes in currents. We will query the existing data to see if these relationships are ever observed as well as testing our understanding of the "normal" pattern of response to tidal currents.Figure 1. Arrows indicate plume orientation at a given time (time axis in days after 9/29/10) and stars indicate times when orientation changes rapidly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22275502','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22275502"><span id="translatedtitle">Life and death of deep-sea <span class="hlt">vents</span>: bacterial diversity and ecosystem succession on inactive <span class="hlt">hydrothermal</span> sulfides.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sylvan, Jason B; Toner, Brandy M; Edwards, Katrina J</p> <p>2012-01-01</p> <p><span class="hlt">Hydrothermal</span> chimneys are a globally dispersed habitat on the seafloor associated with mid-ocean ridge (MOR) spreading centers. Active, hot, <span class="hlt">venting</span> sulfide structures from MORs have been examined for microbial diversity and ecology since their discovery in the mid-1970s, and recent work has also begun to explore the microbiology of inactive sulfides--structures that persist for decades to millennia and form moderate to massive deposits at and below the seafloor. Here we used tag pyrosequencing of the V6 region of the 16S rRNA and full-length 16S rRNA sequencing on inactive <span class="hlt">hydrothermal</span> sulfide chimney samples from 9°N on the East Pacific Rise to learn their bacterial composition, metabolic potential, and succession from <span class="hlt">venting</span> to nonventing (inactive) regimes. Alpha-, beta-, delta-, and gammaproteobacteria and members of the phylum Bacteroidetes dominate all inactive sulfides. Greater than 26% of the V6 tags obtained are closely related to lineages involved in sulfur, nitrogen, iron, and methane cycling. Epsilonproteobacteria represent <4% of the V6 tags recovered from inactive sulfides and 15% of the full-length clones, despite their high abundance in active chimneys. Members of the phylum Aquificae, which are common in active <span class="hlt">vents</span>, were absent from both the V6 tags and full-length 16S rRNA data sets. In both analyses, the proportions of alphaproteobacteria, betaproteobacteria, and members of the phylum Bacteroidetes were greater than those found on active <span class="hlt">hydrothermal</span> sulfides. These shifts in bacterial population structure on inactive chimneys reveal ecological succession following cessation of <span class="hlt">venting</span> and also imply a potential shift in microbial activity and metabolic guilds on <span class="hlt">hydrothermal</span> sulfides, the dominant biome that results from seafloor <span class="hlt">venting</span>. PMID:22275502</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3703532','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3703532"><span id="translatedtitle">Diversity and phylogenetic analyses of bacteria from a shallow-water <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> in Milos island (Greece)</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Giovannelli, Donato; d'Errico, Giuseppe; Manini, Elena; Yakimov, Michail; Vetriani, Costantino</p> <p>2013-01-01</p> <p>Studies of shallow-water <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> have been lagging behind their deep-sea counterparts. Hence, the importance of these systems and their contribution to the local and regional diversity and biogeochemistry is unclear. This study analyzes the bacterial community along a transect at the shallow-water <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> system of Milos island, Greece. The abundance and biomass of the prokaryotic community is comparable to areas not affected by <span class="hlt">hydrothermal</span> activity and was, on average, 1.34 × 108 cells g?1. The abundance, biomass and diversity of the prokaryotic community increased with the distance from the center of the <span class="hlt">vent</span> and appeared to be controlled by the temperature gradient rather than the trophic conditions. The retrieved 16S rRNA gene fragments matched sequences from a variety of geothermal environments, although the average similarity was low (94%), revealing previously undiscovered taxa. Epsilonproteobacteria constituted the majority of the population along the transect, with an average contribution to the total diversity of 60%. The larger cluster of 16S rRNA gene sequences was related to chemolithoautotrophic Sulfurovum spp., an Epsilonproteobacterium so far detected only at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. The presence of previously unknown lineages of Epsilonproteobacteria could be related to the abundance of organic matter in these systems, which may support alternative metabolic strategies to chemolithoautotrophy. The relative contribution of Gammaproteobacteria to the Milos microbial community increased along the transect as the distance from the center of the <span class="hlt">vent</span> increased. Further attempts to isolate key species from these ecosystems will be critical to shed light on their evolution and ecology. PMID:23847607</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3262234','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3262234"><span id="translatedtitle">Life and Death of Deep-Sea <span class="hlt">Vents</span>: Bacterial Diversity and Ecosystem Succession on Inactive <span class="hlt">Hydrothermal</span> Sulfides</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sylvan, Jason B.; Toner, Brandy M.; Edwards, Katrina J.</p> <p>2012-01-01</p> <p>ABSTRACT <span class="hlt">Hydrothermal</span> chimneys are a globally dispersed habitat on the seafloor associated with mid-ocean ridge (MOR) spreading centers. Active, hot, <span class="hlt">venting</span> sulfide structures from MORs have been examined for microbial diversity and ecology since their discovery in the mid-1970s, and recent work has also begun to explore the microbiology of inactive sulfides—structures that persist for decades to millennia and form moderate to massive deposits at and below the seafloor. Here we used tag pyrosequencing of the V6 region of the 16S rRNA and full-length 16S rRNA sequencing on inactive <span class="hlt">hydrothermal</span> sulfide chimney samples from 9°N on the East Pacific Rise to learn their bacterial composition, metabolic potential, and succession from <span class="hlt">venting</span> to nonventing (inactive) regimes. Alpha-, beta-, delta-, and gammaproteobacteria and members of the phylum Bacteroidetes dominate all inactive sulfides. Greater than 26% of the V6 tags obtained are closely related to lineages involved in sulfur, nitrogen, iron, and methane cycling. Epsilonproteobacteria represent <4% of the V6 tags recovered from inactive sulfides and 15% of the full-length clones, despite their high abundance in active chimneys. Members of the phylum Aquificae, which are common in active <span class="hlt">vents</span>, were absent from both the V6 tags and full-length 16S rRNA data sets. In both analyses, the proportions of alphaproteobacteria, betaproteobacteria, and members of the phylum Bacteroidetes were greater than those found on active <span class="hlt">hydrothermal</span> sulfides. These shifts in bacterial population structure on inactive chimneys reveal ecological succession following cessation of <span class="hlt">venting</span> and also imply a potential shift in microbial activity and metabolic guilds on <span class="hlt">hydrothermal</span> sulfides, the dominant biome that results from seafloor <span class="hlt">venting</span>. PMID:22275502</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014DSRI...87...70C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014DSRI...87...70C"><span id="translatedtitle">First insights into macro- and meiofaunal colonisation patterns on paired wood/slate substrata at Atlantic deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cuvelier, Daphne; Beesau, Julie; Ivanenko, Viatcheslav N.; Zeppilli, Daniela; Sarradin, Pierre-Marie; Sarrazin, Jozée</p> <p>2014-05-01</p> <p>In 2006, paired wood and slate panels, each equipped with a temperature probe, were deployed on three different localities on and around the Eiffel Tower edifice (Lucky Strike <span class="hlt">vent</span> field, Mid-Atlantic Ridge) within close proximity of visible <span class="hlt">hydrothermal</span> activity. Recovery of these panels took place in 2008. For this two-year deployment period, the composition of colonising organisms (both macro-and meiofauna) was assessed, along with image analyses of the deployment <span class="hlt">sites</span> in 2006 and 2008. Very few significant differences in colonisation between organic (wood) and inorganic (slate) panels were revealed. Rather, the locality of deployment and the local environmental conditions and <span class="hlt">hydrothermal</span> activity were found to influence taxonomic composition. Variability in microhabitat conditions and biological interactions were hypothesised to interact jointly in shaping new faunal communities on the colonisation substrata.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMOS23A1188L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMOS23A1188L"><span id="translatedtitle">Distributions and contents of the organic carbon and major heavy metals in aquatic environment surrounding the active submarine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> in the Northwestern Pacific</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, S.; Iizasa, K.; Shimoda, G.</p> <p>2009-12-01</p> <p>Since seafloor massive sulfides (SMSs) were firstly found in the central Red Sea in the middle of 20 century, many SMSs have been reported in the settings of oceanic ridges and island arcs. Although seafloor mining of SMSs is likely to be realized in the near future, there are some concerns on <span class="hlt">hydrothermal</span> biota and ambient environments after seafloor mining. As biota and ambient environments will be affected by the mining of SMSs in direct, researches on the aquatic environment surrounding submarine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are strongly needed. Because submarine <span class="hlt">hydrothermal</span> activities are not stable and their life times are relatively short, it is conceivable that the aquatic environments in the <span class="hlt">hydrothermal</span> field are different from the other <span class="hlt">site</span>. Therefore, the regular and the long term monitoring in the aquatic environment of the <span class="hlt">hydrothermal</span> field be strongly required for the more exact and detailed knowledge about the submarine <span class="hlt">hydrothermal</span> environment. The distributions and the contents of organic carbon and major heavy metals in the seawater columns around <span class="hlt">hydrothermal</span> fields will be discussed in the present study. In recent, the submarine <span class="hlt">hydrothermal</span> activities are presumed as one of the factors causing the seasonal fluctuation in concentration of the total organic carbon in the subtropical Northwestern Pacific, but the practical demonstration about this was not carried out yet. The discussion about the distributions and the contents of major heavy metals in the seawater columns around <span class="hlt">hydrothermal</span> fields will help to understanding of the diffusion through the plume discharged from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> to ambient environments. The samples were collected at and around the <span class="hlt">hydrothermal</span> fields of the Bayonnaise Knoll caldera on the back-arc rift and the Myojin Knoll and Myojinsho in the Izu-Ogasawara arc, and the Izena cauldron in Okinawa Trough, during at summer in 2008 and 2009 throughout the HT08 cruise by Hakurei-maru and KT09-12 cruise by Tansei-maru. Seawater samples were vertically collected between surface layer and near bottom by the CTD-rosette system. The samples transferred into acid-cleaned polycarbonate bottles on board, and then the samples were stored under -20 degrees Celsius until analysis to avoid contamination. The concentration of organic carbon was measured by the high-temperature catalytic oxidation method (Shimadzu, TOC-VCSH) with consensus reference materials (CRM). The ICP-MS (Agilent 7500) was employed in the measurement of the heavy metal content. Results of the concentrations about organic carbon and heavy metals obtained in the present study were compared with those of general oceanic environment. We expect that the results will be useful for the more exact understanding about the aquatic environment surrounding the submarine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, and that they also can be used as the basic information at the evaluation of influences during and after the mining of SMSs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20662930','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20662930"><span id="translatedtitle">Geochemical constraints on the diversity and activity of H2 -oxidizing microorganisms in diffuse <span class="hlt">hydrothermal</span> fluids from a basalt- and an ultramafic-hosted <span class="hlt">vent</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Perner, Mirjam; Petersen, Jillian M; Zielinski, Frank; Gennerich, Hans-Hermann; Seifert, Richard</p> <p>2010-10-01</p> <p>Mixing processes of reduced <span class="hlt">hydrothermal</span> fluids with oxygenated seawater and fluid-rock reactions contribute to the chemical signatures of diffuse <span class="hlt">venting</span> and likely determine the geochemical constraints on microbial life. We examined the influence of fluid chemistry on microbial diversity and activity by sampling diffuse fluids emanating through mussel beds at two contrasting <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. The H(2) concentration was very low at the basalt-hosted Clueless <span class="hlt">site</span>, and mixing models suggest O(2) availability throughout much of the habitat. In contrast, effluents from the ultramafic-hosted Quest <span class="hlt">site</span> were considerably enriched in H(2) , while O(2) is likely limited to the mussel layer. Only two different hydrogenase genes were identified in clone libraries from the H(2) -poor Clueless fluids, but these fluids exhibited the highest H(2) uptake rates in H(2) -spiked incubations (oxic conditions, at 18 °C). In contrast, a phylogenetically diverse H(2) -oxidizing potential was associated with distinct thermal conditions in the H(2) -rich Quest fluids, but under oxic conditions, H(2) uptake rates were extremely low. Significant stimulation of CO(2) fixation rates by H(2) addition was solely illustrated in Quest incubations (P-value <0.02), but only in conjunction with anoxic conditions (at 18 °C). We conclude that the factors contributing toward differences in the diversity and activity of H(2) oxidizers at these <span class="hlt">sites</span> include H(2) and O(2) availability. PMID:20662930</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988DSRA...35.1769F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988DSRA...35.1769F"><span id="translatedtitle">Microhabitat variation in the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel, Bathymodiolus thermophilus, at the Rose Garden <span class="hlt">vent</span> on the Galapagos Rift</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fisher, C. R.; Childress, J. J.; Arp, A. J.; Brooks, J. M.; Distel, D.; Favuzzi, J. A.; Felbeck, H.; Hessler, R.; Johnson, K. S.; Kennicutt, M. C.; Macko, S. A.; Newton, A.; Powell, M. A.; Somero, G. N.; Soto, T.</p> <p>1988-10-01</p> <p>Clumps of Bathymodiolus thermophilus were collected from three discrete areas at the 'Rose Garden' <span class="hlt">site</span> on the Galapagos Rift using the deep submersible Alvin. Two mussel collections were made from the central Riftia mass, an area associated with very active <span class="hlt">venting</span>, and three other collections were of two different peripheral mussel clumps. Before collection the clumps were extensively photographed and the water at two of the 'microhabitats' was analysed in situ for oxygen silica, sulfide and temperature. Sulfide levels of up to 300 ?M were recorded at the central collection <span class="hlt">site</span>, while the highest sulfide level recorded at the peripheral <span class="hlt">site</span> assayed was 35 ?M. Levels of RuBP carboxylase activity in the gills were significantly higher in mussels collected from the central ' Riftia <span class="hlt">site</span>' than in either peripheral <span class="hlt">site</span>. ATP sulfurylase was significantly higher in the gills of mussels from the central clump than in one of the peripheral clump collections. The chemical composition (% water, protein, carbohydrate, lipid and ash) and stable carbon isotope ratios ( ?13C) of the mussels showed the same trends, with highest lipid and carbohydrate and the lowest water content and ?13C in the central <span class="hlt">site</span> mussels. Similarly, the mussels from the central <span class="hlt">site</span> were significantly depleted in stable nitrogen ( ?15N) when compared with the peripheral <span class="hlt">site</span> mussels. Variations between <span class="hlt">sites</span> and tissues of the same animal may be indicative of differential utilization of inorganic or dissolved molecular nitrogen sources. The condition index (CI = soft tissue dry mass / internal shell volume) was similar for all animals collected at Rose Garden. The presence of a commensal polychaete, Branchipolynoe symmytilida, in the mantle cavity of the mussels was also correlated with the collection <span class="hlt">site</span>, with the highest incidence of occurrence in the central clump. Levels of the enzyme RuBP carboxylase are quite variable in B. thermophilus and are on the average much lower (0.001 international units) than either Calyptogena magnifica (0.006 I.U.) or Riftia pachyptila (0.16 I.U.). We conclude that the mussels are able to thrive over a wider range of conditions than either C. magnifica or R. pachypila and that this is due to a lesser reliance on their symbiotic bacteria as a source of nutrition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5648541','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5648541"><span id="translatedtitle">Uniformity and diversity in the composition of mineralizing fluids from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the southern Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Philpotts, J.A.; Aruscavage, P.J.; Von Damm, K.L.</p> <p>1987-10-10</p> <p>Abundances of Li, Ni, K, Rb, Ca, Sr, Ba, Mn, Fe, Zn, and Si have been determined in fluid samples from seven <span class="hlt">vents</span> located in three areas on the southern Juan de Fuca Ridge. The <span class="hlt">hydrothermal</span> component estimated from the Mg contents of the samples ranges from 7% to 76%. Concentrations of Fe and Si, among the other elements, in acid-stabilized solutions appear to be generally representative of the parental <span class="hlt">hydrothermal</span> fluids, but some Zn determinations and most Ba values appear to be too low. Thermodynamic calculations indicate that the acidified samples remain supersaturated with respect to silica, barite, and pyrite; unacidified samples are supersaturated, in addition with respect to ZnS, FeS, and many silicate phases. Within the constraints of limited sampling there appear to be differences in fluid compositions both within and between the three <span class="hlt">vent</span> areas. Some uniform differences in the elemental abundances predicted for <span class="hlt">hydrothermal</span> end-member fluids might be due to inmixing of fresh seawater at depth in the <span class="hlt">hydrothermal</span> system. The Juan de Fuca <span class="hlt">hydrothermal</span> fluids contain more Fe but otherwise have relative elemental abundances fairly similar to those in 13 /sup 0/N (East Pacific Rise) fluids, albeit at higher levels. In contrast, fluids from 21 /sup 0/N (East Pacific Rise) and Galapagos have lower K/Rb and much lower Sr and Na abundances; these compositional features probably result from interaction of these fluids with a different mineral assemblage, possibly more mature greenstone. copyright American Geophysical Union 1987</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70014845','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70014845"><span id="translatedtitle">Uniformity and diversity in the composition of mineralizing fluids from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the southern Juan de Fuca Ridge.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Philpotts, J.A.; Aruscavage, P. J.; Von Damm, K. L.</p> <p>1987-01-01</p> <p>Abundances of Li, Na, K, Rb, Ca, Sr, Ba, Mn, Fe, Zn, and Si have been determined in fluid samples from 7 <span class="hlt">vents</span> located in three areas on the southern Juan de Fuca Ridge. The <span class="hlt">hydrothermal</span> component estimated from the Mg contents of the samples ranges from 7% to 76%. Concentrations of Fe and Si, among other elements, in acid-stabilized solutions appear to be generally representative of the parental <span class="hlt">hydrothermal</span> fluids, but some Zn determinations and most Ba values appear to be too low.-from Authors</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22180817','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22180817"><span id="translatedtitle">Draft genome sequence of Caminibacter mediatlanticus strain TB-2, an epsilonproteobacterium isolated from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Giovannelli, Donato; Ferriera, Steven; Johnson, Justin; Kravitz, Saul; Pérez-Rodríguez, Ileana; Ricci, Jessica; O'Brien, Charles; Voordeckers, James W; Bini, Elisabetta; Vetriani, Costantino</p> <p>2011-10-15</p> <p>Caminibacter mediatlanticus strain TB-2(T) [1], is a thermophilic, anaerobic, chemolithoautotrophic bacterium, isolated from the walls of an active deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimney on the Mid-Atlantic Ridge and the type strain of the species. C. mediatlanticus is a Gram-negative member of the Epsilonproteobacteria (order Nautiliales) that grows chemolithoautotrophically with H(2) as the energy source and CO(2) as the carbon source. Nitrate or sulfur is used as the terminal electron acceptor, with resulting production of ammonium and hydrogen sulfide, respectively. In view of the widespread distribution, importance and physiological characteristics of thermophilic Epsilonproteobacteria in deep-sea geothermal environments, it is likely that these organisms provide a relevant contribution to both primary productivity and the biogeochemical cycling of carbon, nitrogen and sulfur at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Here we report the main features of the genome of C. mediatlanticus strain TB-2(T). PMID:22180817</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.B12B..01Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.B12B..01Z"><span id="translatedtitle">Carbon-Isotope Fractionations of Autotrophic Bacteria: Relevance to Primary Production and Microbial Evolution in Hot Springs and <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, C. L.; Romanek, C. S.; Mills, G.</p> <p>2004-12-01</p> <p>Terrestrial hot springs and marine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are often dominated by autotrophic microorganisms. Species of the Bacteria Domain in these environments are known to use different pathways for CO2 fixation. These may include the Calvin cycle, the Acetyl CoA pathway, the reverse TCA cycle, and the 3-HP pathway. Each cycle or pathway may be characterized by distinct patterns of carbon isotope fractionation. This presentation will summarize isotope fractionation patterns associated with known autotrophic bacteria and to use these patterns for interpreting natural isotopic variations. Examples will include hot springs from the Yellowstone National Park and Nevada desert, USA and Kamchatka, Russia, and <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> from the East Pacific Rise. An attempt will be made to discuss isotopic variations within a particular pathway in the context of species evolution through horizontal gene transfer.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://fire.biol.wwu.edu/cmoyer/research/Jesser_qpcr_loihi_aem15.pdf','EPRINT'); return false;" href="http://fire.biol.wwu.edu/cmoyer/research/Jesser_qpcr_loihi_aem15.pdf"><span id="translatedtitle">Quantitative PCR Analysis of Functional Genes in Iron-Rich Microbial Mats at an Active <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> System (Lo'ihi Seamount,</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Moyer, Craig</p> <p></p> <p><span class="hlt">Vent</span> System (Lo'ihi Seamount, Hawai'i) Kelsey J. Jesser, Heather Fullerton, Kevin W. Hager, Craig L'ihi Seamount, located 35 km southeast off the big island of Hawai'i, which is characterized by low'ihi Seamount. Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are dynamic and extremely pro- ductive biological ecosystems</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4442600','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4442600"><span id="translatedtitle">The Production of Methane, Hydrogen, and Organic Compounds in Ultramafic-Hosted <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> of the Mid-Atlantic Ridge</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Charlou, J.L.; Holm, N.G.; Mousis, O.</p> <p>2015-01-01</p> <p>Abstract Both hydrogen and methane are consistently discharged in large quantities in <span class="hlt">hydrothermal</span> fluids issued from ultramafic-hosted <span class="hlt">hydrothermal</span> fields discovered along the Mid-Atlantic Ridge. Considering the vast number of these fields discovered or inferred, <span class="hlt">hydrothermal</span> fluxes represent a significant input of H2 and CH4 to the ocean. Although there are lines of evidence of their abiogenic formation from stable C and H isotope results, laboratory experiments, and thermodynamic data, neither their origin nor the reaction pathways generating these gases have been fully constrained yet. Organic compounds detected in the fluids may also be derived from abiotic reactions. Although thermodynamics are favorable and extensive experimental work has been done on Fischer-Tropsch-type reactions, for instance, nothing is clear yet about their origin and formation mechanism from actual data. Since chemolithotrophic microbial communities commonly colonize <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, biogenic and thermogenic processes are likely to contribute to the production of H2, CH4, and other organic compounds. There seems to be a consensus toward a mixed origin (both sources and processes) that is consistent with the ambiguous nature of the isotopic data. But the question that remains is, to what proportions? More systematic experiments as well as integrated geochemical approaches are needed to disentangle <span class="hlt">hydrothermal</span> geochemistry. This understanding is of prime importance considering the implications of <span class="hlt">hydrothermal</span> H2, CH4, and organic compounds for the ocean global budget, global cycles, and the origin of life. Key Words: Hydrogen—Methane—Organics—MAR—Abiotic synthesis—Serpentinization—Ultramafic-hosted <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Astrobiology 15, 381–399. PMID:25984920</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26410427','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26410427"><span id="translatedtitle">Characteristics of the cultivable bacteria from sediments associated with two deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in Okinawa Trough.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sun, Qing-Lei; Wang, Ming-Qing; Sun, Li</p> <p>2015-12-01</p> <p>In this study, different culture-dependent methods were used to examine the cultivable heterotrophic bacteria in the sediments associated with two deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> (named HV1 and HV2) located at Iheya Ridge and Iheya North in Okinawa Trough. The two <span class="hlt">vents</span> differed in morphology, with HV1 exhibiting diffuse flows while HV2 being a black smoker with a chimney-like structure. A total of 213 isolates were identified by near full-length 16S rRNA gene sequence analysis. Of these isolates, 128 were from HV1 and 85 were from HV2. The bacterial community structures were, in large parts, similar between HV1 and HV2. Nevertheless, differences between HV1 and HV2 were observed in one phylum, one class, 4 orders, 10 families, and 20 genera. Bioactivity analysis revealed that 25 isolates belonging to 9 different genera exhibited extracellular protease activities, 21 isolates from 11 genera exhibited extracellular lipase activities, and 13 isolates of 8 genera displayed antimicrobial activities. This is the first observation of a large population of bacteria with extracellular bioactivities existing in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Taken together, the results of this study provide new insights into the characteristics of the cultivable heterotrophic bacteria in deep-sea <span class="hlt">hydrothermal</span> ecosystems. PMID:26410427</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=123976','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=123976"><span id="translatedtitle">Neutrophilic Fe-Oxidizing Bacteria Are Abundant at the Loihi Seamount <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> and Play a Major Role in Fe Oxide Deposition</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Emerson, David; Moyer, Craig L.</p> <p>2002-01-01</p> <p>A number of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> exist on the summit of the Loihi Seamount, a shield volcano that is part of the Hawaiian archipelago. The <span class="hlt">vents</span> are 1,100 to 1,325 m below the surface and range in temperature from slightly above ambient (10°C) to high temperature (167°C). The <span class="hlt">vent</span> fluid is characterized by high concentrations of CO2 (up to 17 mM) and Fe(II) (up to 268 ?M), but there is a general paucity of H2S. Most of the <span class="hlt">vents</span> are surrounded by microbial mats that have a gelatinous texture and are heavily encrusted with rust-colored Fe oxides. Visually, the Fe oxides appeared homogeneous. However, light microscopy revealed that the oxides had different morphologies, which fell into three classes: (i) sheaths, (ii) twisted or irregular filaments, and (iii) amorphous oxides. A morphological analysis of eight different samples indicated that the amorphous oxides were overall the most abundant; however, five <span class="hlt">sites</span> had >50% sheaths and filamentous oxides. These latter morphologies are most likely the direct result of microbial deposition. Direct cell counts revealed that all of the oxides had abundant microbial populations associated with them, from 6.9 × 107 to 5.3 × 108 cells per ml of mat material. At most <span class="hlt">sites</span>, end point dilution series for lithotrophic Fe oxidizers were successful out to dilutions of 10?6 and 10?7. A pure culture was obtained from a 10?7 dilution tube; this strain, JV-1, was an obligate, microaerophilic Fe oxidizer that grew at 25 to 30°C. A non-cultivation-based molecular approach with terminal-restriction fragment length polymorphism also indicated the common presence of Fe-oxidizing bacteria at Loihi. Together, these results indicate that Fe-oxidizing bacteria are common at the Loihi Seamount and probably play a major role in Fe oxidation. A review of the literature suggests that microbially mediated Fe oxidation at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> may be important globally. PMID:12039770</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3741630','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3741630"><span id="translatedtitle">New insights into <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> processes in the unique shallow-submarine arc-volcano, Kolumbo (Santorini), Greece</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kilias, Stephanos P.; Nomikou, Paraskevi; Papanikolaou, Dimitrios; Polymenakou, Paraskevi N.; Godelitsas, Athanasios; Argyraki, Ariadne; Carey, Steven; Gamaletsos, Platon; Mertzimekis, Theo J.; Stathopoulou, Eleni; Goettlicher, Joerg; Steininger, Ralph; Betzelou, Konstantina; Livanos, Isidoros; Christakis, Christos; Bell, Katherine Croff; Scoullos, Michael</p> <p>2013-01-01</p> <p>We report on integrated geomorphological, mineralogical, geochemical and biological investigations of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field located on the floor of the density-stratified acidic (pH ~ 5) crater of the Kolumbo shallow-submarine arc-volcano, near Santorini. Kolumbo features rare geodynamic setting at convergent boundaries, where arc-volcanism and seafloor <span class="hlt">hydrothermal</span> activity are occurring in thinned continental crust. Special focus is given to unique enrichments of polymetallic spires in Sb and Tl (±Hg, As, Au, Ag, Zn) indicating a new hybrid seafloor analogue of epithermal-to-volcanic-hosted-massive-sulphide deposits. Iron microbial-mat analyses reveal dominating ferrihydrite-type phases, and high-proportion of microbial sequences akin to "Nitrosopumilus maritimus", a mesophilic Thaumarchaeota strain capable of chemoautotrophic growth on <span class="hlt">hydrothermal</span> ammonia and CO2. Our findings highlight that acidic shallow-submarine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> nourish marine ecosystems in which nitrifying Archaea are important and suggest ferrihydrite-type Fe3+-(hydrated)-oxyhydroxides in associated low-temperature iron mats are formed by anaerobic Fe2+-oxidation, dependent on microbially produced nitrate. PMID:23939372</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23939372','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23939372"><span id="translatedtitle">New insights into <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> processes in the unique shallow-submarine arc-volcano, Kolumbo (Santorini), Greece.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kilias, Stephanos P; Nomikou, Paraskevi; Papanikolaou, Dimitrios; Polymenakou, Paraskevi N; Godelitsas, Athanasios; Argyraki, Ariadne; Carey, Steven; Gamaletsos, Platon; Mertzimekis, Theo J; Stathopoulou, Eleni; Goettlicher, Joerg; Steininger, Ralph; Betzelou, Konstantina; Livanos, Isidoros; Christakis, Christos; Bell, Katherine Croff; Scoullos, Michael</p> <p>2013-01-01</p> <p>We report on integrated geomorphological, mineralogical, geochemical and biological investigations of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field located on the floor of the density-stratified acidic (pH ~ 5) crater of the Kolumbo shallow-submarine arc-volcano, near Santorini. Kolumbo features rare geodynamic setting at convergent boundaries, where arc-volcanism and seafloor <span class="hlt">hydrothermal</span> activity are occurring in thinned continental crust. Special focus is given to unique enrichments of polymetallic spires in Sb and Tl (±Hg, As, Au, Ag, Zn) indicating a new hybrid seafloor analogue of epithermal-to-volcanic-hosted-massive-sulphide deposits. Iron microbial-mat analyses reveal dominating ferrihydrite-type phases, and high-proportion of microbial sequences akin to "Nitrosopumilus maritimus", a mesophilic Thaumarchaeota strain capable of chemoautotrophic growth on <span class="hlt">hydrothermal</span> ammonia and CO2. Our findings highlight that acidic shallow-submarine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> nourish marine ecosystems in which nitrifying Archaea are important and suggest ferrihydrite-type Fe(3+)-(hydrated)-oxyhydroxides in associated low-temperature iron mats are formed by anaerobic Fe(2+)-oxidation, dependent on microbially produced nitrate. PMID:23939372</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25964331','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25964331"><span id="translatedtitle">Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> bacteria related to human pathogenic Vibrio species.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hasan, Nur A; Grim, Christopher J; Lipp, Erin K; Rivera, Irma N G; Chun, Jongsik; Haley, Bradd J; Taviani, Elisa; Choi, Seon Young; Hoq, Mozammel; Munk, A Christine; Brettin, Thomas S; Bruce, David; Challacombe, Jean F; Detter, J Chris; Han, Cliff S; Eisen, Jonathan A; Huq, Anwar; Colwell, Rita R</p> <p>2015-05-26</p> <p>Vibrio species are both ubiquitous and abundant in marine coastal waters, estuaries, ocean sediment, and aquaculture settings worldwide. We report here the isolation, characterization, and genome sequence of a novel Vibrio species, Vibrio antiquarius, isolated from a mesophilic bacterial community associated with <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> located along the East Pacific Rise, near the southwest coast of Mexico. Genomic and phenotypic analysis revealed V. antiquarius is closely related to pathogenic Vibrio species, namely Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio harveyi, and Vibrio vulnificus, but sufficiently divergent to warrant a separate species status. The V. antiquarius genome encodes genes and operons with ecological functions relevant to the environment conditions of the deep sea and also harbors factors known to be involved in human disease caused by freshwater, coastal, and brackish water vibrios. The presence of virulence factors in this deep-sea Vibrio species suggests a far more fundamental role of these factors for their bacterial host. Comparative genomics revealed a variety of genomic events that may have provided an important driving force in V. antiquarius evolution, facilitating response to environmental conditions of the deep sea. PMID:25964331</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4498644','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4498644"><span id="translatedtitle">Phylogeny and New Classification of <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> and Seep Shrimps of the Family Alvinocarididae (Decapoda)</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Vereshchaka, Alexander L.; Kulagin, Dmitry N.; Lunina, Anastasia A.</p> <p>2015-01-01</p> <p>The paper addresses the phylogeny and classification of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> shrimp family Alvinocarididae. Two morphological cladistic analyses were carried out, which use all 31 recognized species of Alvinocarididae as terminal taxa. As outgroups, two species were included, both representing major caridean clades: Acanthephyra purpurea (Acanthephyridae) and Alpheus echiurophilus (Alpheidae). For additional support of the clades we utilised available data on mitochondrial Cytochrome c Oxidase I gene (CO1) and 16S ribosomal markers. Both morphological and molecular methods resulted in similar tree topologies and nearly identical clades. We consider these clades as evolutionary units and thus erect two new subfamilies: Rimicaridinae (Alvinocaridinides, Manuscaris, Opaepele, Shinkaicaris, Rimicaris), Alvinocaridinae (Alvinocaris), whilst recognising Mirocaridinae (with genera Mirocaris and Nautilocaris) at subfamily level. One genus, Keldyshicaris could not be assigned to any subfamily and is thus left as incertae sedis. The monophyly of Alvinocardinae was supported by morphological data, but not supported by molecular data (two analyses); the monophyly of all subfamilies was supported both by morphological and molecular data. Chorocaris is herein synonymized with Rimicaris, whilst Opaepele vavilovi is herein transferred to a new genus Keldyshicaris. Morphological trends within Alvinocarididae are discussed and short biogeographical remarks are given. We provide emended diagnoses for all subfamilies and genera along with keys to all recognized species. PMID:26161742</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3111178','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3111178"><span id="translatedtitle">The Biological Deep Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> as a Model to Study Carbon Dioxide Capturing Enzymes</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Minic, Zoran; Thongbam, Premila D.</p> <p>2011-01-01</p> <p>Deep sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are located along the mid-ocean ridge system, near volcanically active areas, where tectonic plates are moving away from each other. Sea water penetrates the fissures of the volcanic bed and is heated by magma. This heated sea water rises to the surface dissolving large amounts of minerals which provide a source of energy and nutrients to chemoautotrophic organisms. Although this environment is characterized by extreme conditions (high temperature, high pressure, chemical toxicity, acidic pH and absence of photosynthesis) a diversity of microorganisms and many animal species are specially adapted to this hostile environment. These organisms have developed a very efficient metabolism for the assimilation of inorganic CO2 from the external environment. In order to develop technology for the capture of carbon dioxide to reduce greenhouse gases in the atmosphere, enzymes involved in CO2 fixation and assimilation might be very useful. This review describes some current research concerning CO2 fixation and assimilation in the deep sea environment and possible biotechnological application of enzymes for carbon dioxide capture. PMID:21673885</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3695450','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3695450"><span id="translatedtitle">Identity and mechanisms of alkane-oxidizing metalloenzymes from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Bertrand, Erin M.; Keddis, Ramaydalis; Groves, John T.; Vetriani, Costantino; Austin, Rachel Narehood</p> <p>2013-01-01</p> <p>Six aerobic alkanotrophs (organism that can metabolize alkanes as their sole carbon source) isolated from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> were characterized using the radical clock substrate norcarane to determine the metalloenzyme and reaction mechanism used to oxidize alkanes. The organisms studied were Alcanivorax sp. strains EPR7 and MAR14, Marinobacter sp. strain EPR21, Nocardioides sp. strains EPR26w, EPR28w, and Parvibaculum hydrocarbonoclasticum strain EPR92. Each organism was able to grow on n-alkanes as the sole carbon source and therefore must express genes encoding an alkane-oxidizing enzyme. Results from the oxidation of the radical-clock diagnostic substrate norcarane demonstrated that five of the six organisms (EPR7, MAR14, EPR21, EPR26w, and EPR28w) used an alkane hydroxylase functionally similar to AlkB to catalyze the oxidation of medium-chain alkanes, while the sixth organism (EPR92) used an alkane-oxidizing cytochrome P450 (CYP)-like protein to catalyze the oxidation. DNA sequencing indicated that EPR7 and EPR21 possess genes encoding AlkB proteins, while sequencing results from EPR92 confirmed the presence of a gene encoding CYP-like alkane hydroxylase, consistent with the results from the norcarane experiments. PMID:23825470</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4450432','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4450432"><span id="translatedtitle">Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> bacteria related to human pathogenic Vibrio species</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hasan, Nur A.; Grim, Christopher J.; Lipp, Erin K.; Rivera, Irma N. G.; Chun, Jongsik; Haley, Bradd J.; Taviani, Elisa; Choi, Seon Young; Hoq, Mozammel; Munk, A. Christine; Brettin, Thomas S.; Bruce, David; Challacombe, Jean F.; Detter, J. Chris; Han, Cliff S.; Eisen, Jonathan A.; Huq, Anwar; Colwell, Rita R.</p> <p>2015-01-01</p> <p>Vibrio species are both ubiquitous and abundant in marine coastal waters, estuaries, ocean sediment, and aquaculture settings worldwide. We report here the isolation, characterization, and genome sequence of a novel Vibrio species, Vibrio antiquarius, isolated from a mesophilic bacterial community associated with <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> located along the East Pacific Rise, near the southwest coast of Mexico. Genomic and phenotypic analysis revealed V. antiquarius is closely related to pathogenic Vibrio species, namely Vibrio alginolyticus, Vibrio parahaemolyticus, Vibrio harveyi, and Vibrio vulnificus, but sufficiently divergent to warrant a separate species status. The V. antiquarius genome encodes genes and operons with ecological functions relevant to the environment conditions of the deep sea and also harbors factors known to be involved in human disease caused by freshwater, coastal, and brackish water vibrios. The presence of virulence factors in this deep-sea Vibrio species suggests a far more fundamental role of these factors for their bacterial host. Comparative genomics revealed a variety of genomic events that may have provided an important driving force in V. antiquarius evolution, facilitating response to environmental conditions of the deep sea. PMID:25964331</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25984920','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25984920"><span id="translatedtitle">The production of methane, hydrogen, and organic compounds in ultramafic-hosted <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> of the mid-atlantic ridge.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Konn, C; Charlou, J L; Holm, N G; Mousis, O</p> <p>2015-05-01</p> <p>Both hydrogen and methane are consistently discharged in large quantities in <span class="hlt">hydrothermal</span> fluids issued from ultramafic-hosted <span class="hlt">hydrothermal</span> fields discovered along the Mid-Atlantic Ridge. Considering the vast number of these fields discovered or inferred, <span class="hlt">hydrothermal</span> fluxes represent a significant input of H2 and CH4 to the ocean. Although there are lines of evidence of their abiogenic formation from stable C and H isotope results, laboratory experiments, and thermodynamic data, neither their origin nor the reaction pathways generating these gases have been fully constrained yet. Organic compounds detected in the fluids may also be derived from abiotic reactions. Although thermodynamics are favorable and extensive experimental work has been done on Fischer-Tropsch-type reactions, for instance, nothing is clear yet about their origin and formation mechanism from actual data. Since chemolithotrophic microbial communities commonly colonize <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, biogenic and thermogenic processes are likely to contribute to the production of H2, CH4, and other organic compounds. There seems to be a consensus toward a mixed origin (both sources and processes) that is consistent with the ambiguous nature of the isotopic data. But the question that remains is, to what proportions? More systematic experiments as well as integrated geochemical approaches are needed to disentangle <span class="hlt">hydrothermal</span> geochemistry. This understanding is of prime importance considering the implications of <span class="hlt">hydrothermal</span> H2, CH4, and organic compounds for the ocean global budget, global cycles, and the origin of life. PMID:25984920</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4426611','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4426611"><span id="translatedtitle">The uptake and excretion of partially oxidized sulfur expands the repertoire of energy resources metabolized by <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> symbioses</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Beinart, R. A.; Gartman, A.; Sanders, J. G.; Luther, G. W.; Girguis, P. R.</p> <p>2015-01-01</p> <p>Symbiotic associations between animals and chemoautotrophic bacteria crowd around <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. In these associations, symbiotic bacteria use chemical reductants from <span class="hlt">venting</span> fluid for the energy to support autotrophy, providing primary nutrition for the host. At <span class="hlt">vents</span> along the Eastern Lau Spreading Center, the partially oxidized sulfur compounds (POSCs) thiosulfate and polysulfide have been detected in and around animal communities but away from <span class="hlt">venting</span> fluid. The use of POSCs for autotrophy, as an alternative to the chemical substrates in <span class="hlt">venting</span> fluid, could mitigate competition in these communities. To determine whether ESLC symbioses could use thiosulfate to support carbon fixation or produce POSCs during sulfide oxidation, we used high-pressure, flow-through incubations to assess the productivity of three symbiotic mollusc genera—the snails Alviniconcha spp. and Ifremeria nautilei, and the mussel Bathymodiolus brevior—when oxidizing sulfide and thiosulfate. Via the incorporation of isotopically labelled inorganic carbon, we found that the symbionts of all three genera supported autotrophy while oxidizing both sulfide and thiosulfate, though at different rates. Additionally, by concurrently measuring their effect on sulfur compounds in the aquaria with voltammetric microelectrodes, we showed that these symbioses excreted POSCs under highly sulfidic conditions, illustrating that these symbioses could represent a source for POSCs in their habitat. Furthermore, we revealed spatial disparity in the rates of carbon fixation among the animals in our incubations, which might have implications for the variability of productivity in situ. Together, these results re-shape our thinking about sulfur cycling and productivity by <span class="hlt">vent</span> symbioses, demonstrating that thiosulfate may be an ecologically important energy source for <span class="hlt">vent</span> symbioses and that they also likely impact the local geochemical regime through the excretion of POSCs. PMID:25876848</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25876848','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25876848"><span id="translatedtitle">The uptake and excretion of partially oxidized sulfur expands the repertoire of energy resources metabolized by <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> symbioses.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Beinart, R A; Gartman, A; Sanders, J G; Luther, G W; Girguis, P R</p> <p>2015-05-01</p> <p>Symbiotic associations between animals and chemoautotrophic bacteria crowd around <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. In these associations, symbiotic bacteria use chemical reductants from <span class="hlt">venting</span> fluid for the energy to support autotrophy, providing primary nutrition for the host. At <span class="hlt">vents</span> along the Eastern Lau Spreading Center, the partially oxidized sulfur compounds (POSCs) thiosulfate and polysulfide have been detected in and around animal communities but away from <span class="hlt">venting</span> fluid. The use of POSCs for autotrophy, as an alternative to the chemical substrates in <span class="hlt">venting</span> fluid, could mitigate competition in these communities. To determine whether ESLC symbioses could use thiosulfate to support carbon fixation or produce POSCs during sulfide oxidation, we used high-pressure, flow-through incubations to assess the productivity of three symbiotic mollusc genera-the snails Alviniconcha spp. and Ifremeria nautilei, and the mussel Bathymodiolus brevior-when oxidizing sulfide and thiosulfate. Via the incorporation of isotopically labelled inorganic carbon, we found that the symbionts of all three genera supported autotrophy while oxidizing both sulfide and thiosulfate, though at different rates. Additionally, by concurrently measuring their effect on sulfur compounds in the aquaria with voltammetric microelectrodes, we showed that these symbioses excreted POSCs under highly sulfidic conditions, illustrating that these symbioses could represent a source for POSCs in their habitat. Furthermore, we revealed spatial disparity in the rates of carbon fixation among the animals in our incubations, which might have implications for the variability of productivity in situ. Together, these results re-shape our thinking about sulfur cycling and productivity by <span class="hlt">vent</span> symbioses, demonstrating that thiosulfate may be an ecologically important energy source for <span class="hlt">vent</span> symbioses and that they also likely impact the local geochemical regime through the excretion of POSCs. PMID:25876848</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/10966393','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/10966393"><span id="translatedtitle">Novel bacterial and archaeal lineages from an in situ growth chamber deployed at a Mid-Atlantic Ridge <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Reysenbach, A L; Longnecker, K; Kirshtein, J</p> <p>2000-09-01</p> <p>The phylogenetic diversity was determined for a microbial community obtained from an in situ growth chamber placed on a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> on the Mid-Atlantic Ridge (23 degrees 22' N, 44 degrees 57' W). The chamber was deployed for 5 days, and the temperature within the chamber gradually decreased from 70 to 20 degrees C. Upon retrieval of the chamber, the DNA was extracted and the small-subunit rRNA genes (16S rDNA) were amplified by PCR using primers specific for the Archaea or Bacteria domain and cloned. Unique rDNA sequences were identified by restriction fragment length polymorphisms, and 38 different archaeal and bacterial phylotypes were identified from the 85 clones screened. The majority of the archaeal sequences were affiliated with the Thermococcales (71%) and Archaeoglobales (22%) orders. A sequence belonging to the Thermoplasmales confirms that thermoacidophiles may have escaped enrichment culturing attempts of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> samples. Additional sequences that represented deeply rooted lineages in the low-temperature eurarchaeal (marine group II) and crenarchaeal clades were obtained. The majority of the bacterial sequences obtained were restricted to the Aquificales (18%), the epsilon subclass of the Proteobacteria (epsilon-Proteobacteria) (40%), and the genus Desulfurobacterium (25%). Most of the clones (28%) were confined to a monophyletic clade within the epsilon-Proteobacteria with no known close relatives. The prevalence of clones related to thermophilic microbes that use hydrogen as an electron donor and sulfur compounds (S(0), SO(4), thiosulfate) indicates the importance of hydrogen oxidation and sulfur metabolism at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. The presence of sequences that are related to sequences from hyperthermophiles, moderate thermophiles, and mesophiles suggests that the diversity obtained from this analysis may reflect the microbial succession that occurred in response to the shift in temperature and possible associated changes in the chemistry of the <span class="hlt">hydrothermal</span> fluid. PMID:10966393</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1212826I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1212826I"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> fluids <span class="hlt">vented</span> at shallow depths at the Aeolian islands: relationships with volcanic and geothermal systems.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Italiano, Francesco; Caracausi, Antonio; Longo, Manfredi; Maugeri, Roberto; Paonita, Antonio</p> <p>2010-05-01</p> <p>Scuba diving investigations carried out over the last two decades at the Aeolian islands revealed the existence of submarine magmatic and late-magmatic <span class="hlt">hydrothermalism</span> at all the islands, despite the absence of on-shore activity at some of the islands. The results gained by diving activities provided useful information to evaluate the volcanic and geothermal activity and to manage the volcanic crisis occurred on November 2002 off the island of Panarea. Scuba diving investigations carried out from middle 80's, had shown that despite the absence of on shore volcanic manifestations, submarine <span class="hlt">hydrothermal</span> activity is recognizable at shallow depth around all the Aeolian islands related either to volcanic and geothermal activity. The sampled gases are CO2-dominated with low amounts of oxygen and reactive gases (H2, CO, CH4 and H2S) with concentrations ranging from a few ppm to some mole percent. Sometimes significant N2 amount are detectable together with high helium contents. Samples having low CO2 content, besides relevant N2 and He amounts, are the consequence of CO2 dissolution in sea-water due to gas-water interactions (GWI) occurred before the sample collection. The high CO2 solubility (878 ml/l, T=20°C, P=1bar) may, in fact, decrease the CO2 content in the <span class="hlt">venting</span> gases thus increasing the concentrations of the less soluble species (e.g. He 8 ml/l, CO 23 ml/l and CH4 33.8 ml/l) in the gas mixture. Such a process might occur at any level, however, because of the slow water circulation in deep sediments, CO2 is able to saturate the circulating sea-water. The isotopic composition of carbon displays a small range of values while helium isotopes are in the range of 4.1<Rac<7. Despite the gases come from both active and extinct Volcanoes, their chemical composition is similar. Contrastingly the isotope composition of helium shows a large heterogeneity with the highest isotopic ratios surprisingly measured at the extinct volcanic islands in the western sector, and much lower values detected in <span class="hlt">venting</span> gases from active volcanoes (e.g. Vulcano and Panarea). The explanation of such a difference is not related to the volcanic activity at all, but to the parent mantle that in the western side looks to be less contaminated compared to the eastern side. Crustal contamination has been invoked by several authors as the main factor that caused the dramatic 3He/4He decrease. Although the parent mantle produced magmas with different isotopic signature, the gas phase looks similar. To explain the results of the chemical analyses it is proposed that similar deep boundary conditions (pressure, temperature, oxidation level) act as buffers for the chemical composition of the <span class="hlt">venting</span> gases. With the aim of investigating their origin, estimations of the deep equilibration conditions have been carried out. The reactive compounds detected in the sampled gases, largely used for geothermometric and geobarometric considerations of <span class="hlt">hydrothermal</span> fluids were used in a system based on the CH4-CO-CO2 contents assuming the presence of a boiling aqueous solution. The equilibrium constants of the adopted reactions are a function of temperature and oxygen fugacity, being the latter buffered by the mineral assemblage of the host rocks. Due to the similarity in the chemical composition of the gases <span class="hlt">vented</span> at all the islands, a theoretical model developed to interpret the chemical composition of the gases released at Panarea during the last volcanic crisis is here applied. The results have shown that geothermal boiling systems are detectable at all the islands with temperatures up to 350°C. The adopted geo-thermobarometric system is more sensitive to the contents of CO and CH4 than that of CO2, implying that although GWI induce modifications in the chemical composition, the estimated equilibrium temperatures do not change very much for variations of the CO2 content in the range of several volume percent, thus, whether or not the gaseous mixture underwent GWI. Moreover, the slow reaction kinetics of CO and CH4 allow them to keep the deep equilibrium c</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.B13C1102O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.B13C1102O"><span id="translatedtitle">Imaging microbial metal metabolism in situ under conditions of the deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oger, P. M.; Daniel, I.; Simionovici, A.; Picard, A.</p> <p>2006-12-01</p> <p>High-pressure biotopes are the most widely spread biotopes on Earth. They represent one possible location for the origin of life. They also share striking similarities with extraterrestrial biotopes such as those postulated for Europe or Mars. In absence of light, dissimilatory reduction of metals (DMR) is fueling the ecosystem. Monitoring the metabolism of the deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> microbial fauna under P, T and chemical conditions relevant to their isolation environment can be difficult because of the confinement and because most spectroscopic probes do not sense metallic ions in solution. We demonstrated the possibility to use Xray spectroscopy to monitor the speciation of metallic species in solution. Experiments were performed at The ESRF using Selenium (Se) detoxification by Agrobacterium tumefaciens as an analog of DMR. The reduction of Se from selenite to the metal was monitored by a combiantion of two Xray spectroscopic techniques (XANES and ?XRF). Cells were incubated in the low pressure DAC in growth medium supplemented with 5mM Selenite and incubated under pressures up to 60 Mpa at 30°C for 24h. The evolution of the speciation can be easily monitored and the concentration of each Se species determined from the Xray spectra by linear combinations of standard spectra. Selenite is transformed by the bacterium into a mixture of metal Se and methylated Se after 24 hours. Se detoxification is observed in situ up to at least 25 MPa. The technique, developped for Se can be adapted to monitor other elements more relevant to DMR such as As, Fe or S, which should allow to monitor in situ under controlled pressure and temperature the metabolism of <span class="hlt">vent</span> organisms. It is also amenable to the monitoring of toxic metals. Xray spectroscopy and the lpDAC are compatible with other spectroscopic techniques, such as Raman, UV or IR spectroscopies, allowing to probe other metabolic activities. Hence, enlarging the range of metabolic information that can be obtained in situ. Oger PM, I Daniel, B Cournoyer, and A Simionovici (2004) Spectrochim Acta B 59:1681-1686 Oger PM, I Daniel, and A Picard (2006) BBA Prot Proteom 1764:434-442</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3740784','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3740784"><span id="translatedtitle">A hybrid zone between Bathymodiolus mussel lineages from eastern Pacific <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2013-01-01</p> <p>Background The inhabitants of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> occupy ephemeral island-like habitats distributed sporadically along tectonic spreading-centers, back-arc basins, and volcanically active seamounts. The majority of <span class="hlt">vent</span> taxa undergo a pelagic larval phase, and thus varying degrees of geographical subdivision, ranging from no impedance of dispersal to complete isolation, often exist among taxa that span common geomorphological boundaries. Two lineages of Bathymodiolus mussels segregate on either side of the Easter Microplate, a boundary that separates the East Pacific Rise from spreading centers connected to the Pacific-Antarctic Ridge. Results A recent sample from the northwest flank of the Easter Microplate contained an admixture of northern and southern mitochondrial haplotypes and corresponding alleles at five nuclear gene loci. Genotypic frequencies in this sample did not fit random mating expectation. Significant heterozygote deficiencies at nuclear loci and gametic disequilibria between loci suggested that this transitional region might be a ‘Tension Zone’ maintained by immigration of parental types and possibly hybrid unfitness. An analysis of recombination history in the nuclear genes suggests a prolonged history of parapatric contact between the two mussel lineages. We hereby elevate the southern lineage to species status as Bathymodiolus antarcticus n. sp. and restrict the use of Bathymodiolus thermophilus to the northern lineage. Conclusions Because B. thermophilus s.s. exhibits no evidence for subdivision or isolation-by-distance across its 4000 km range along the EPR axis and Galápagos Rift, partial isolation of B. antarcticus n. sp. requires explanation. The time needed to produce the observed degree of mitochondrial differentiation is consistent with the age of the Easter Microplate (2.5 to 5.3 million years). The complex geomorphology of the Easter Microplate region forces strong cross-axis currents that might disrupt self-recruitment of mussels by removing planktotrophic larvae from the ridge axis. Furthermore, frequent local extinction events in this tectonically dynamic region might produce a demographic sink rather than a source for dispersing mussel larvae. Historical changes in tectonic rates and current patterns appear to permit intermittent contact and introgression between the two species. PMID:23347448</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1713046K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1713046K"><span id="translatedtitle">Cinnabar, arsenian pyrite and thallium-enrichment in active shallow submarine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> at Paleochori Bay, Milos Island, Greece</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kati, Marianna; Voudouris, Panagiotis; Valsami-Jones, Eugenia; Magganas, Andreas; Baltatzis, Emmanouil; Kanellopoulos, Christos; Mavrogonatos, Constantinos</p> <p>2015-04-01</p> <p>We herein report the discovery of active cinnabar-depositing <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in a submarine setting at Paleochori Bay, within the offshore southeastern extension of the Milos Island Geothermal Field, South Aegean Active Volcanic Arc. Active, low temperature (up to 115 °C) <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> through volcaniclastic material has led to a varied assemblage of sulfide and alteration mineral phases in an area of approximately 1 km2. Our samples recovered from Paleochori Bay are <span class="hlt">hydrothermal</span> edifices composed of volcaniclastic detrital material cemented by pyrite, or pure sulfide (mainly massive pyrite) mounts. Besides pyrite and minor marcasite, the <span class="hlt">hydrothermal</span> minerals include cinnabar, amorphous silica, hydrous ferric oxides, carbonates (aragonite and calcite), alunite-jarosite solid solution and Sr-rich barite. Among others, growth textures, sieve-textured pyrite associated with barite, alunite-jarosite solid solution and hydrous ferric oxides rims colloform-banded pyrite layers. Overgrowths of arsenian pyrite layers (up to 3.2 wt. % As and/or up to 1.1 wt. % Mn) onto As-free pyrite indicate fluctuation in As content of the <span class="hlt">hydrothermal</span> fluid. Mercury, in the form of cinnabar, occurs in up to 5 ?m grains within arsenian pyrite layers, usually forming distinct cinnabar-enriched micro-layers. <span class="hlt">Hydrothermal</span> Sr-rich barite (barite-celestine solid solution), pseudocubic alunite-jarosite solid solution and Mn- and Sr-enriched carbonates occur in various amounts and closely associated with pyrite and/or hydrous ferric oxides. Thallium-bearing sulfides and/or sulfosalts were not detected during our study; however, hydrous ferric oxides show thallium content of up to 0.5 wt. % Tl. The following scenarios may have played a role in pyrite precipitation at Paleochori: (a) H2S originally dissolved in the deep fluid but separated upon boiling could have reacted with oxygenated seawater under production of sulphuric acid, thus causing leaching and dissolution of primary iron-rich grains from the volcaniclastic components of the sediments and resulting in precipitation of pyrite; (b) the iron may also have been derived by the near-neutral reduced <span class="hlt">hydrothermal</span> brines and precipitate metal sulfides as a result of cooling, mixing with seawaters; the necessary iron content to form sulfides is mostly derived from primary iron-rich components of the basement; (c) biological activity may have resulted in pyrite deposition (e.g. sulfur is provided by a biogenic reduction of marine sulphate). The mineralogy of <span class="hlt">hydrothermal</span> precipitates considered in the present study resemble <span class="hlt">hydrothermal</span> products from other shallow water <span class="hlt">venting</span> areas elsewhere: Lihir and Ambitle Islands, Papua New Guinea, Kraternaya Bight, Kuriles, Russia, Punta Mita and Bahía Concepción, Mexico and Punta Banda at Baja California. The Paleochori <span class="hlt">vents</span> contain the first documented occurrence of cinnabar on the sea floor in the Aegean area and provide an important link between offshore <span class="hlt">hydrothermal</span> activity and the mercury-depositing mineralizing system on Milos Island. An interplay between bacterial activity, pH, Eh, temperature, precipitation rate and iron concentration resulted in precipitation of As-pyrite with interlayered cinnabar, hydrous ferric oxides enriched in thallium, alunite-jarosite solid solution and carbonates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/11542933','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/11542933"><span id="translatedtitle">A Mossbauer investigation of iron-rich terrestrial <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems: lessons for Mars exploration.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wade, M L; Agresti, D G; Wdowiak, T J; Armendarez, L P; Farmer, J D</p> <p>1999-04-25</p> <p><span class="hlt">Hydrothermal</span> spring systems may well have been present on early Mars and could have served as a habitat for primitive life. The integrated instrument suite of the Athena Rover has, as a component on the robotic arm, a Mossbauer spectrometer. In the context of future Mars exploration we present results of Mossbauer analysis of a suite of samples from an iron-rich thermal spring in the Chocolate Pots area of Yellowstone National Park (YNP) and from Obsidian Pool (YNP) and Manitou Springs, Colorado. We have found that Mossbauer spectroscopy can discriminate among the iron-bearing minerals in our samples. Those near the <span class="hlt">vent</span> and on the surface are identified as ferrihydrite, an amorphous ferric mineraloid. Subsurface samples, collected from cores, which are likely to have undergone inorganic and/or biologically mediated alteration (diagenesis), exhibit spectral signatures that include nontronite (a smectite clay), hematite (alpha-Fe2O3), small-particle/nanophase goethite (alpha-FeOOH), and siderite (FeCO3). We find for iron minerals that Mossbauer spectroscopy is at least as efficient in identification as X-ray diffraction. This observation is important from an exploration standpoint. As a planetary surface instrument, Mossbauer spectroscopy can yield high-quality spectral data without sample preparation (backscatter mode). We have also used field emission scanning electron microscopy (FESEM), in conjunction with energy-dispersive X ray (EDX) fluorescence spectroscopy, to characterize the microbiological component of surface sinters and the relation between the microbiological and the mineralogical framework. Evidence is presented that the minerals found in these deposits can have multi-billion-year residence times and thus may have survived their possible production in a putative early Martian hot spring up to the present day. Examples include the nanophase property and the Mossbauer signature for siderite, which has been identified in a 2.09-billion-year old hematite-rich chert stromatolite. Our research demonstrates that in situ Mossbauer spectroscopy can help determine whether <span class="hlt">hydrothermal</span> mineral deposits exist on Mars, which is significant for exobiology because of the issue of whether that world ever had conditions conductive to the origin of life. As a useful tool for selection of samples suitable for transport to Earth, Mossbauer spectroscopy will not only serve geological interests but will also have potential for exopaleontology. PMID:11542933</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040088936&hterms=chocolate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dchocolate','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040088936&hterms=chocolate&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dchocolate"><span id="translatedtitle">A Mossbauer investigation of iron-rich terrestrial <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems: lessons for Mars exploration</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wade, M. L.; Agresti, D. G.; Wdowiak, T. J.; Armendarez, L. P.; Farmer, J. D.</p> <p>1999-01-01</p> <p><span class="hlt">Hydrothermal</span> spring systems may well have been present on early Mars and could have served as a habitat for primitive life. The integrated instrument suite of the Athena Rover has, as a component on the robotic arm, a Mossbauer spectrometer. In the context of future Mars exploration we present results of Mossbauer analysis of a suite of samples from an iron-rich thermal spring in the Chocolate Pots area of Yellowstone National Park (YNP) and from Obsidian Pool (YNP) and Manitou Springs, Colorado. We have found that Mossbauer spectroscopy can discriminate among the iron-bearing minerals in our samples. Those near the <span class="hlt">vent</span> and on the surface are identified as ferrihydrite, an amorphous ferric mineraloid. Subsurface samples, collected from cores, which are likely to have undergone inorganic and/or biologically mediated alteration (diagenesis), exhibit spectral signatures that include nontronite (a smectite clay), hematite (alpha-Fe2O3), small-particle/nanophase goethite (alpha-FeOOH), and siderite (FeCO3). We find for iron minerals that Mossbauer spectroscopy is at least as efficient in identification as X-ray diffraction. This observation is important from an exploration standpoint. As a planetary surface instrument, Mossbauer spectroscopy can yield high-quality spectral data without sample preparation (backscatter mode). We have also used field emission scanning electron microscopy (FESEM), in conjunction with energy-dispersive X ray (EDX) fluorescence spectroscopy, to characterize the microbiological component of surface sinters and the relation between the microbiological and the mineralogical framework. Evidence is presented that the minerals found in these deposits can have multi-billion-year residence times and thus may have survived their possible production in a putative early Martian hot spring up to the present day. Examples include the nanophase property and the Mossbauer signature for siderite, which has been identified in a 2.09-billion-year old hematite-rich chert stromatolite. Our research demonstrates that in situ Mossbauer spectroscopy can help determine whether <span class="hlt">hydrothermal</span> mineral deposits exist on Mars, which is significant for exobiology because of the issue of whether that world ever had conditions conductive to the origin of life. As a useful tool for selection of samples suitable for transport to Earth, Mossbauer spectroscopy will not only serve geological interests but will also have potential for exopaleontology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DSRII.121...31O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DSRII.121...31O"><span id="translatedtitle">Microbial biofilms associated with fluid chemistry and megafaunal colonization at post-eruptive deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>O'Brien, Charles E.; Giovannelli, Donato; Govenar, Breea; Luther, George W.; Lutz, Richard A.; Shank, Timothy M.; Vetriani, Costantino</p> <p>2015-11-01</p> <p>At deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, reduced, super-heated <span class="hlt">hydrothermal</span> fluids mix with cold, oxygenated seawater. This creates temperature and chemical gradients that support chemosynthetic primary production and a biomass-rich community of invertebrates. In late 2005/early 2006 an eruption occurred on the East Pacific Rise at 9°50?N, 104°17?W. Direct observations of the post-eruptive diffuse-flow <span class="hlt">vents</span> indicated that the earliest colonizers were microbial biofilms. Two cruises in 2006 and 2007 allowed us to monitor and sample the early steps of ecosystem recovery. The main objective of this work was to characterize the composition of microbial biofilms in relation to the temperature and chemistry of the <span class="hlt">hydrothermal</span> fluids and the observed patterns of megafaunal colonization. The area selected for this study had local seafloor habitats of active diffuse flow (in-flow) interrupted by adjacent habitats with no apparent expulsion of <span class="hlt">hydrothermal</span> fluids (no-flow). The in-flow habitats were characterized by higher temperatures (1.6-25.2 °C) and H2S concentrations (up to 67.3 ?M) than the no-flow habitats, and the microbial biofilms were dominated by chemosynthetic Epsilonproteobacteria. The no-flow habitats had much lower temperatures (1.2-5.2 °C) and H2S concentrations (0.3-2.9 ?M), and Gammaproteobacteria dominated the biofilms. Siboglinid tubeworms colonized only in-flow habitats, while they were absent at the no-flow areas, suggesting a correlation between siboglinid tubeworm colonization, active <span class="hlt">hydrothermal</span> flow, and the composition of chemosynthetic microbial biofilms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20000081244&hterms=Hares&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DHares','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20000081244&hterms=Hares&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DHares"><span id="translatedtitle">Identifying Martian <span class="hlt">Hydrothermal</span> <span class="hlt">Sites</span>: Geological Investigation Utilizing Multiple Datasets</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dohm, J. M.; Baker, V. R.; Anderson, R. C.; Scott, D. H.; Rice, J. W., Jr.; Hare, T. M.</p> <p>2000-01-01</p> <p>Comprehensive geological investigations of martian landscapes that may have been modified by magmatic-driven <span class="hlt">hydrothermal</span> activity, utilizing multiple datasets, will yield prime target <span class="hlt">sites</span> for future hydrological, mineralogical, and biological investigations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMEP51B0840W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMEP51B0840W"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">Venting</span> at Lake Rotomahana, New Zealand, 125 Years After the Tarawera Eruption of 1886</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Walker, S. L.; de Ronde, C. E.; Fornari, D. J.; Leybourne, M. I.; Ferrini, V.; Kukulya, A.; Littlefield, R.; Scott, B. J.; Immenga, D.; Baker, E. T.</p> <p>2011-12-01</p> <p>In early 1886 Lake Rotomahana (North Island, NZ) was a small, shallow lake surrounded on its northern side by a geothermal field that included New Zealand's first major tourist attraction: the beautiful Pink and White (silica sinter) Terraces. The lake dramatically changed on 10 June 1886 when nearby Mt Tarawera erupted. Volcanic and <span class="hlt">hydrothermal</span> explosions left the landscape scarred with explosion craters, blanketed with ash and mud, and devoid of vegetation. A large, steaming crater replaced the lake and the Pink and White Terraces were apparently destroyed. The crater re-filled during the next 15 years and today Lake Rotomahana is considerably deeper (125 m) and ~5 times larger than pre-eruption. While the evolution of a new geothermal field adjacent to the lake (Waimangu) has been visible and documented over the past 125 years, the evolution of the area perturbed by the eruption then subsequently submerged has been mostly inaccessible. A detailed survey of Lake Rotomahana was conducted in Jan/Feb 2011 to identify the extent and nature of present-day <span class="hlt">venting</span>. Two autonomous underwater vehicles (AUV) with temperature, pH, turbidity, and oxidation-reduction potential (ORP) sensors completed 18 missions covering a total distance of ~250 km (20-50 m line spacing; 10-15 m altitude). Water samples were collected at 14 CTD stations for chemical analyses. The lake is stratified during summer months with average surface (0-10 m depth) temperatures ~21.5°C. The topmost 1-3 meters are 0.5-1°C warmer near the boiling springs and geysers that flow into the lake on the western shore. Temperatures decrease from 21.2-16.5°C within the thermocline (12-16 m), then to 14.54°C at depth (110 m). pH values in the surface layer range from 7.4-7.9, decreasing to 6.50 below ~30 m. Temperature, pH and ORP anomalies in the water column identify at least five areas where warm water is <span class="hlt">venting</span> into the lake: 1) in the area of the historic Pink Terraces (+3.5°C, -0.1 pH, -142 mv); 2) over a bathymetric high near the north shore between the Pink Terraces and "The Pinnacle" (+4°C, -0.08 pH, -20 mv); 3) through a broad area south of the 1886 rift, west of Patiti Island (+0.11°C, -0.08 pH, -30 mv); 4) near the historic location of the White Terraces (+0.1°C, -22 mv above the lakebed, with sediment temperature, inadvertently sampled by the CTD, >18°C); and 5) at a bathymetric high near the north shore of the east basin (+0.22°C, -0.13 pH, -1 mv). Gas bubbles also stream from the lakebed at most of these locations. Water samples from below the thermocline at locations 4 and 5 above had the highest 3He concentrations measured during this survey. This near-bottom AUV survey has allowed us to map the post-eruption <span class="hlt">hydrothermal</span> discharge zones in Lake Rotomahana with far greater detail than has previously been possible. The eruption of 1886 altered the geothermal system significantly, resulting in new areas of geothermal activity both within and beyond the lake, although the hot springs that created the famed terraces are still active in approximately the same location as they were prior to the eruption.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://arxiv.org/pdf/1212.2271v1','EPRINT'); return false;" href="http://arxiv.org/pdf/1212.2271v1"><span id="translatedtitle">Major transitions in evolution linked to thermal gradients above <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Anthonie W. J. Muller</p> <p>2012-12-03</p> <p>The emergence of the main divisions of today's life: (1) unicellular prokaryotes, (2) unicellular eukaryotes, (3) multicellular eukaryotes, and (4) metazoans, are examples of the--still unexplained--major transitions in evolution. Regarding the origin of life, I have proposed that primordial life functioned as heat engine (thermosynthesis) while thermally cycled in convecting volcanic hot springs. Here I argue for a role of thermal gradients above submarine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> (SHV) in several major transitions. The last decade has witnessed the emergence of phononics, a novel discipline in physics based on controlled heat transport in thermal gradients. It builds thermal analogs to electronic devices: the thermal diode, the thermal transistor, the thermal switch, the thermal amplifier, the thermal memory--the thermal computer has been proposed. Encouraged by (1) the many similarities between microtubules (MT) and carbon nanotubes, which have a very high thermal conductivity, and (2) the recent discovery of a silk protein which also has a very high thermal conductivity, I combine and extend the mentioned ideas, and propose the general conjecture that several major transitions of evolution were effected by thermal processes, with four additional partial conjectures: (1) The first organisms used heat engines during thermosynthesis in convection cells; (2) The first eukaryotic cells used MT during thermosynthesis in the thermal gradient above SHV; (3) The first metazoans used transport of water or in water during thermosynthesis above SHV under an ice-covered ocean during the Gaskiers Snowball Earth; and (4) The first mammalian brain used a thermal machinery based on thermal gradients in or across the cortex. When experimentally proven these conjectures, which are testable by the methods of synthetic biology, would significantly enhance our understanding of life.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015FrES..tmp...55C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015FrES..tmp...55C"><span id="translatedtitle">Multiple-scale temporal variations and fluxes near a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> over the Southwest Indian Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Xiaodan; Liang, Chujin; Dong, Changming; Zhou, Beifeng; Liao, Guanghong; Li, Junde</p> <p>2015-09-01</p> <p>A deep-ocean mooring system was deployed 100 m away from an active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> over the Southwest Indian Ridge (SWIR), where the water depth is about 2,800 m. One year of data on ocean temperature 50 m away from the ocean floor and on velocities at four levels (44 m, 40 m, 36 m, and 32 m away from the ocean floor) were collected by the mooring system. Multiplescale variations were extracted from these data: seasonal, tidal, super-tidal, and eddy scales. The semidiurnal tide was the strongest tidal signal among all the tidal constituents in both currents and temperature. With the multiple-scale variation presented in the data, a new method was developed to decompose the data into five parts in terms of temporal scales: time-mean, seasonal, tidal, super-tidal, and eddy. It was shown that both eddy and tidal heat (momentum) fluxes were characterized by variation in the bottom topography: the tidal fluxes of heat and momentum in the along-isobath direction were much stronger than those in the cross-isobath direction. For the heat flux, eddy heat flux was stronger than tidal heat flux in the cross-isobath direction, while eddy heat flux was weaker in the along-isobath direction. For the momentum flux, the eddy momentum flux was weaker than tidal momentum flux in both directions. The eddy momentum fluxes at the four levels had a good relationship with the magnitude of mean currents: it increased with the mean current in an exponential relationship.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015FrES....9..691C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015FrES....9..691C"><span id="translatedtitle">Multiple-scale temporal variations and fluxes near a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> over the Southwest Indian Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Xiaodan; Liang, Chujin; Dong, Changming; Zhou, Beifeng; Liao, Guanghong; Li, Junde</p> <p>2015-12-01</p> <p>A deep-ocean mooring system was deployed 100 m away from an active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> over the Southwest Indian Ridge (SWIR), where the water depth is about 2,800 m. One year of data on ocean temperature 50 m away from the ocean floor and on velocities at four levels (44 m, 40 m, 36 m, and 32 m away from the ocean floor) were collected by the mooring system. Multiplescale variations were extracted from these data: seasonal, tidal, super-tidal, and eddy scales. The semidiurnal tide was the strongest tidal signal among all the tidal constituents in both currents and temperature. With the multiple-scale variation presented in the data, a new method was developed to decompose the data into five parts in terms of temporal scales: time-mean, seasonal, tidal, super-tidal, and eddy. It was shown that both eddy and tidal heat (momentum) fluxes were characterized by variation in the bottom topography: the tidal fluxes of heat and momentum in the along-isobath direction were much stronger than those in the cross-isobath direction. For the heat flux, eddy heat flux was stronger than tidal heat flux in the cross-isobath direction, while eddy heat flux was weaker in the along-isobath direction. For the momentum flux, the eddy momentum flux was weaker than tidal momentum flux in both directions. The eddy momentum fluxes at the four levels had a good relationship with the magnitude of mean currents: it increased with the mean current in an exponential relationship.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25428420','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25428420"><span id="translatedtitle">Vitellibacter nionensis sp. nov., isolated from a shallow water <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rajasabapathy, Raju; Mohandass, Chellandi; Yoon, Jung-Hoon; Dastager, Syed Gulam; Liu, Qing; Khieu, Thi-Nhan; Son, Chu Ky; Li, Wen-Jun; Colaço, Ana</p> <p>2015-02-01</p> <p>A novel, Gram-stain-negative, non-motile, rod-shaped yellow bacterium, designated VBW088(T) was isolated from a shallow water <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> in Espalamaca in the Azores. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain VBW088(T) clustered with three type strains of species of the genus Vitellibacter and exhibited a sequence similarity of 97.3 % with Vitellibacter soesokkakensis RSSK-12(T). However, strain VBW088(T) and V. soesokkakensis RSSK-12(T) exhibited low DNA-DNA relatedness (12.7±3.5 %). Strain VBW088(T) was positive for catalase and oxidase. Growth occurred at 10-37 °C, with the optimum at 30 °C, and at pH 6.0-8.0 (optimum pH 6.0) and in up to 5 % (w/v) NaCl with optimum growth at 1-2 % (w/v) NaCl. The major fatty acids (>10 %) were iso-C15 : 0 (33.5 %) and iso-C17 : 0 3-OH (32.0 %). The polar lipids detected in strain VBW088(T) consisted of phosphatidylethanolamine, one unidentified aminolipid and three unidentified phospholipids. The DNA G+C content of strain VBW088(T) was 36.7 mol%. On the basis of phylogenetic inference, DNA-DNA relatedness, chemotaxonomic analysis and physiological data, the isolate represents a novel species of the genus Vitellibacter, for which the name Vitellibacter nionensis sp. nov. is proposed, with the type strain as VBW088(T) (?= KCTC 32420(T)?= MCC 2354(T)). PMID:25428420</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20010023092&hterms=Hares&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DHares','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20010023092&hterms=Hares&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DHares"><span id="translatedtitle">Martian Magmatic-Driven <span class="hlt">Hydrothermal</span> <span class="hlt">Sites</span>: Potential Sources of Energy, Water, and Life</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Anderson, R. C.; Dohm, J. M.; Baker, V. R.; Ferris, J. C.; Hare, T. M.; Tanaka, K. L.; Klemaszewski, J. E.; Skinner, J. A.; Scott, D. H.</p> <p>2000-01-01</p> <p>Magmatic-driven processes and impact events dominate the geologic record of Mars. Such recorded geologic activity coupled with significant evidence of past and present-day water/ice, above and below the martian surface, indicate that <span class="hlt">hydrothermal</span> environments certainly existed in the past and may exist today. The identification of such environments, especially long-lived magmatic-driven <span class="hlt">hydrothermal</span> environments, provides NASA with significant target <span class="hlt">sites</span> for future sample return missions, since they (1) could favor the development and sustenance of life, (2) may comprise a large variety of exotic mineral assemblages, and (3) could potentially contain water/ice reservoirs for future Mars-related human activities. If life developed on Mars, the fossil record would presumably be at its greatest concentration and diversity in environments where long-term energy sources and water coexisted such as at <span class="hlt">sites</span> where long-lived, magmatic-driven <span class="hlt">hydrothermal</span> activity occurred. These assertions are supported by terrestrial analogs. Small, single-celled creatures (prokaryotes) are vitally important in the evolution of the Earth; these prokaryotes are environmentally tough and tolerant of environmental extremes of pH, temperature, salinity, and anoxic conditions found around <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. In addition, there is a great ability for bacteria to survive long periods of geologic time in extreme conditions, including high temperature hydrogen sulfide and sulfur erupted from Mount St. Helens volcano. Our team of investigators is conducting a geological investigation using multiple mission-derived datasets (e.g., existing geologic map data, MOC imagery, MOLA, TES image data, geophysical data, etc.) to identify prime target <span class="hlt">sites</span> of <span class="hlt">hydrothermal</span> activity for future hydrological, mineralogical, and biological investigations. The identification of these <span class="hlt">sites</span> will enhance the probability of success for future missions to Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20080018899&hterms=Sulfur&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DSulfur','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080018899&hterms=Sulfur&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DSulfur"><span id="translatedtitle">Thermococcus thioreducens sp. nov., a Novel Hyperthermophilic, Obligately Sulfur-Reducing Archaeon from a Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pikuta, Elena V.; Marsic, Damien; Itoh, Takashi; Bej, Asim K.; Tang, Jane; Whitman, William B.; Ng, Joseph D.; Garriott, Owen K.; Hoover, Richard B.</p> <p>2007-01-01</p> <p>A hyperthermophilic, sulfur-reducing, organo-heterotrophic archaeon, strain OGL-20P(sup T), was isolated from 'black smoker' chimney material from the Rainbow <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">site</span> on the Mid-Atlantic Ridge (36.2degN, 33.9degW). The cells of strain OGL-20P(T) have an irregular coccoid shape and are motile with a single flagellum. Growth was observed within a pH range of 5.0-8.5 (optimum pH 7.0), an NaCl concentration range of 1-5%(w/v) (optimum 3%)and a temperature range of 55-94 C (optimum 83-85 C). The novel isolate is strictly anaerobic and obligately dependent upon elemental sulfur as an electron acceptor, but it does not reduce sulfate, sulfite, thiosulfate, Fe(III) or nitrate. Proteolysis products (peptone, bacto-tryptone, Casamino acids and yeast extract) are utilized as substrates during sulfur reduction. Strain OGL-20P(sup T) is resistant to ampicillin, chloram phenicol, kanamycin and gentamicin, but sensitive to tetracycline and rifampicin. The G + C content of the DNA is 52.9 mol% The 16S rRNA gene sequence analysis revealed that strain OGL-20P(sup T) is closely related to Thermococcus coalescens and related species, but no significant homology by DNA-DNA hybridization was observed between those species and the new isolate. On the basis of physiological and molecular properties of the new isolate, we conclude that strain OGL-20P(sup T) represents a new separate species within the genus Thermococcus, for which we propose the name Thermococcus thioreducens sp. nov. The type strain is OGL-20P(sup T) (=JCM 12859(exp T) = DSM 14981(exp T)=ATCC BAA-394(exp T)).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20030065875&hterms=Sulfur&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DSulfur','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20030065875&hterms=Sulfur&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DSulfur"><span id="translatedtitle">Thermococcus Thioreducens sp. nov., A Novel Hyperthermophilic, Obligately Sulfur-Reducing Archaeon from a Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pikuta, Elena V.; Hoover, Richard B.; Marsic, Damien; Bej, Asim K.; Garriott, Owen</p> <p>2003-01-01</p> <p>A novel hyperthermophilic organo-heterotrophic archaeon, strain OGL-20P(sup T), was isolated from 'black smoker' chimney material from the Rainbow <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">site</span> on the Mid-Atlantic Ridge (36.2 N; 33.9 W). The cells of strain OGL-20P(sup T) have an irregular coccoid shape and are motile with a single flagellum. Growth was observed to occur within the pH range 5.0-8.5 (optimum pH 7.0), NaCl concentration range 1-5 % (w/v) (optimum 3 %), and temperature range 55-94 C (optimum 83-85 C). Novel isolate is strictly anaerobic and obligately dependent from elemental sulfur as electron acceptor, but it cannot reduce sulfate, sulfite, thiosulfate, iron (III) or nitrate. Proteolysis products that can be utilized as substrates during sulfur-reduction are: peptone, bactotryptone, casamino-acids, and yeast extract. Strain OGL-20P(sup T) is resistant to ampicillin, chloramphenicol, kanamycin, and gentamycin, but sensitive to tetracycline and rifampicin. The G+C content of DNA is 57.1 mol% . Comparative 16S rRNA gene sequence analysis revealed that strain OGL-20P(sup T) is most closely related to Thermococcus celer and 'T. barossii', but no significant homology by DNA-DNA hybridization was observed between those species and the new isolate. On the basis of physiological and molecular properties of the new isolate, the name Thermococcus thioreducens sp. nov., is proposed. The type strain is OGL-20P(sup T) (= ATCC BAA-394(sup T) = DSM 1498(sup T)).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020067739&hterms=Anaerobic+respiration&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2528Anaerobic%2Brespiration%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020067739&hterms=Anaerobic+respiration&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2528Anaerobic%2Brespiration%2529"><span id="translatedtitle">Thermococcus sulfurophilus sp. nov., a New Hyperthermophilic, Sulfur-Reducing Archaeon Isolated from Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pikuta, Elena V.; Hoover, Richard B.; Whitman, William B.; Marsic, Damien; Garriott, Owen; Six, N. Frank (Technical Monitor)</p> <p>2002-01-01</p> <p>A new hyperthermophilic, anaerobic, sulfur-reducing, organo-heterotrophic archaeon, strain OGL-20P, was isolated from "black smoker" chimney material at the Rainbow <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">site</span> in the Atlantic Ocean (36.2 N; 33.9 W). The cells of strain OGL-20P have irregular coccoid shape and are motile with a single flagellum. Growth occurs within pH range of 5.5-8.2 (optimal at pH 7.0-7.2), salinity range of 1-5% NaCl (optimal concentration 3% NaCl wt/vol), and temperature range of +55 C to +94 C (optimal growth at +83 C to +85 C). Strain OGL-20P is resistant to freezing (at -20 C). New isolate is strictly anaerobic with sulfur-type of respiration. A limited number of compounds are utilized as electron donors, including peptone, becto-tryptone, casamino-acids, and yeast extract but does not grow with separate amino acids. Sulfur and Iron can be used as electron acceptors; but not sulfate, sulfite, thiosulfate or nitrate. Strain OGL-20P is resistant to chloramphenicol, kanamycin, and gentamycin. Growth of str. OGL20P is inhibited by tetracyclin but not by Na2MoO4. The G+C content of DNA is 57.2 mol%. The 16S ribosomal RNA sequence analysis allows one to classify strain OGL-20P as a representative of a now species of Thermococcus genus. The name Thermococcus sulfurophilus op. nov., was suggested for the new isolate, type strain OGL-20P (sup T) (= ATCC BAA_394 (sup T) = DSM...(supT)).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070014795','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070014795"><span id="translatedtitle">Thermococcus Thioreducens sp. Nov., a Novel Hyperthermophilic, Obligately Sulfur-reducing Archaeon from a Deep-sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pikuta, Elena V.; Marsic, Damien; Itoh, Takashi; Bej, Asim K.; Tang, Jane; Whitman, William B.; Ng, Joseph D.; Garriott, Owen K.; Hoover, Richard B.</p> <p>2007-01-01</p> <p>A hyperthermophilic, sulfur-reducing, organo-heterotrophic archaeon, strain OGL-20P was isolated from black smoker chimney material from the Rainbow <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">site</span> on the Mid-Atlantic Ridge (36.2 N, 33.9 W). The cells of strain OGL-20P(sup T) have an irregular coccoid shape and are motile with a single flagellum. Growth was observed within the pH range 5.0-8.5 (optimum pH 7.0), NaCl concentration range 1-5 % (w/v) (optimum 3%), and temperature range 55-94 C (optimum 83-85 C). The novel isolate is strictly anaerobic and obligately dependent upon elemental sulfur as an electron acceptor, but it does not reduce sulfate, sulfite, thiosulfate, iron (III) or nitrate. Proteolysis products (peptone, bacto-tryptone, casamino-acids, and yeast extract) are utilized as substrates during sulfur-reduction. Strain OGL-20P(sup T) is resistant to ampicillin, chloramphenicol, kanamycin, and gentamycin, but sensitive to tetracycline and rifampicin. The G+C content of DNA is 52.9 mol%. The 16S rRNA gene sequence analysis revealed that strain OGL-20P(sup T) is closely related to Thermococcus coalescens and related species, but no significant homology by DNA-DNA hybridization was observed between those species and the new isolate. On the basis of physiological and molecular properties of the new isolate, we conclude that strain OGL-20P(sup T) represents a new separate species within the genus Thermococcus, and propose the name Thermococcus thioreducens sp. nov. The type strain is OGL-20P(sup T) (= ATCC BAA-394(sup T) = JCM 12859(sup T) = DSM 14981(sup T)).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS13B1729P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS13B1729P"><span id="translatedtitle">Modeling the <span class="hlt">hydrothermal</span> circulation and the hydrogen production at the Rainbow <span class="hlt">site</span> with Cast3M</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Perez, F.; Mügler, C.; Charlou, J.; Jean-baptiste, P.</p> <p>2012-12-01</p> <p>On the Mid-Atlantic Ridge, the Rainbow <span class="hlt">venting</span> <span class="hlt">site</span> is described as an ultramafic-hosted active <span class="hlt">hydrothermal</span> <span class="hlt">site</span> and releases high fluxes of methane and hydrogen [1, 2]. This behavior has first been interpreted as the result of serpentinization processes. But geochemical reactions involving olivine and plagioclase assemblages, and leading to chlorite, tremolite, talc and magnetite assemblages, could contribute to the observed characteristics of the exiting fluid [2]. The predominance of one of these geochemical reactions or their coexistence strongly depend on the <span class="hlt">hydrothermal</span> fluid circulation. We developed and validated a 2D/3D numerical model using a Finite Volume method to simulate heat driven fluid flows in the framework of the Cast3M code [3, 4]. We also developed a numerical model for hydrogen production and transport that is based on experimental studies of the serpentinization processes [5-6]. This geochemical model takes into account the exothermic and water-consuming behavior of the serpentinization reaction and it can be coupled to our thermo-hydrogeological model. Our simulations provide temperatures, mass fluxes and <span class="hlt">venting</span> surface areas very close to those estimated in-situ [7]. We showed that a single-path model [8] was necessary to simulate high values such as the in-situ measured temperatures and estimated water mass fluxes of the Rainbow <span class="hlt">site</span> [7]. This single-path model will be used to model the production and transport of hydrogen at the Rainbow <span class="hlt">hydrothermal</span> <span class="hlt">site</span>. References [1]Charlou et al. (2010) AGU Monograph series. [2]Seyfried et al. (2011) Geochim. Cosmochim. Acta 75, 1574-1593. [3]http://www-cast3m.cea.fr. [4]Martin & Fyfe (1970) Chem. Geol. 6, 185-202. [5] Marcaillou et al. (2011) Earth and Planet. Sci. Lett. 303, 281-290. [6]Malvoisin et al. (2012) JGR, 117, B01104. [7]Perez et al. (2012) submited to Computational Geosciences. [8]Lowell & Germanovich (2004) AGU, Washington DC, USA.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.B33A0846R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.B33A0846R"><span id="translatedtitle">Zeta-Proteobacteria dominate the formation of microbial mats in low-temperature <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> at Loihi Seamount</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rassa, A. C.; McAllister, S. M.; Safran, S. A.; Moyer, C. L.</p> <p>2007-12-01</p> <p>Loihi Seamount is Hawaii's youngest volcano and one of the earth's most active. Loihi is located 30 km SE of the big island of Hawaii and rises over 3000m above the sea floor and summits at 1100m below sea level. An eruption in 1996 of Loihi led to the formation of Pele's Pit, a 300 meter deep caldera. The current observations have revealed diffuse <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> causing low to intermediate temperatures (10 to 65°C). The elevated temperatures, coupled with high concentrations of Fe(II) (ranging from 50 to 750 ?M) support conditions allowing for extensive microbial mat formation. The focus of this study was to identify the colonizing populations of bacteria generated by the microbial mats at Loihi Seamount. Twenty-six microbial growth chambers were deployed and recovered after placement in the flow of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> for 3 to 8 days from within Loihi's caldera. Genomic DNA was extracted from samples and analyzed by Terminal-Restriction Fragment Length Polymorphism (T-RFLP) using eight restriction enzyme treatments to generate fingerprints from bacterial amplicons of small subunit rRNA genes (SSU rDNAs). Pearson product-moment coupled with UPGMA cluster analysis of these T-RFLP fingerprints showed that these communities bifurcated into two primary clusters. The first (Group 1) had an average <span class="hlt">vent</span> effluent temperature of 44°C, and the second (Group 2) had an average <span class="hlt">vent</span> effluent temperature of 64°C. Representative samples from within the two clusters (or groups) were chosen for further clone library and sequencing analysis. These libraries revealing a dominance of the recently discovered zeta- Proteobacteria in the lower temperature group (Group 1) indicating that they were the dominant colonizers of the microbial mats. These microaerophilic, obligately lithotrophic, Fe-oxidizing bacteria are most closely related to Mariprofundus ferrooxydans. The higher temperature group (Group 2) was dominated by epsilon- Proteobacteria primarily of the genus Sulfurimonas, which are sulfur- and thiosulfate-oxidizing bacteria.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21585736','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21585736"><span id="translatedtitle">Development and characterization of 12 microsatellite markers from the deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> siboglinid Riftia pachyptila.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fusaro, A J; Baco, A R; Gerlach, G; Shank, T M</p> <p>2008-01-01</p> <p>Ecological processes at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on fast-spreading mid-ocean ridges are punctuated by frequent physical disturbance, often accompanied by a high occurrence of population turnover. To persist through local extinction events, sessile invertebrate species living in these geologically and chemically dynamic habitats depend on larval dispersal. We characterized 12 polymorphic microsatellite loci from one such species, the siboglinid tubeworm Riftia pachyptila. All loci conformed to Hardy-Weinberg expectations without linkage (mean H(E)  = 0.9405, mean N(A)  = 20.25). These microsatellites are being employed in the investigation of spatial and temporal population genetic structure in the eastern Pacific Ocean. PMID:21585736</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70033086','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70033086"><span id="translatedtitle">Integrated Fe- and S-isotope study of seafloor <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> at East Pacific Rise 9-10°N</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Rouxel, O.; Shanks, Wayne C., III; Bach, W.; Edwards, K.J.</p> <p>2008-01-01</p> <p>In this study, we report on coupled Fe- and S-isotope systematics of <span class="hlt">hydrothermal</span> fluids and sulfide deposits from the East Pacific Rise at 9–10°N to better constrain processes affecting Fe-isotope fractionation in <span class="hlt">hydrothermal</span> environments. We aim to address three fundamental questions: (1) Is there significant Fe-isotope fractionation during sulfide precipitation? (2) Is there significant variability of Fe-isotope composition of the <span class="hlt">hydrothermal</span> fluids reflecting sulfide precipitation in subsurface environments? (3) Are there any systematics between Fe- and S-isotopes in sulfide minerals? The results show that chalcopyrite, precipitating in the interior wall of a <span class="hlt">hydrothermal</span> chimney displays a limited range of ?56Fe values and ?34S values, between ? 0.11 to ? 0.33‰ and 2.2 to 2.6‰ respectively. The ?56Fe values are, on average, slightly higher by 0.14‰ relative to coeval <span class="hlt">vent</span> fluid composition while ?34S values suggest significant S-isotope fractionation (? 0.6 ± 0.2‰) during chalcopyrite precipitation. In contrast, systematically lower ?56Fe and ?34S values relative to <span class="hlt">hydrothermal</span> fluids, by up to 0.91‰ and 2.0‰ respectively, are observed in pyrite and marcasite precipitating in the interior of active chimneys. These results suggest isotope disequilibrium in both Fe- and S-isotopes due to S-isotopic exchange between <span class="hlt">hydrothermal</span> H2S and seawater SO42? followed by rapid formation of pyrite from FeS precursors, thus preserving the effects of a strong kinetic Fe-isotope fractionation during FeS precipitation. In contrast, ?56Fe and ?34S values of pyrite from inactive massive sulfides, which show evidence of extensive late-stage reworking, are essentially similar to the <span class="hlt">hydrothermal</span> fluids. Multiple stages of remineralization of ancient chimney deposits at the seafloor appear to produce minimal Fe-isotope fractionation. Similar affects are indicated during subsurface sulfide precipitation as demonstrated by the lack of systematic differences between ?56Fe values in both high-temperature, Fe-rich black smokers and lower-temperature, Fe-depleted <span class="hlt">vents</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=194926','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=194926"><span id="translatedtitle">Evidence of Chemolithoautotrophy in the Bacterial Community Associated with Alvinella pompejana, a <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Polychaete</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Campbell, Barbara J.; Stein, Jeffrey L.; Cary, S. Craig</p> <p>2003-01-01</p> <p>The deep-sea polychaete Alvinella pompejana colonizes tubes on the sides of black smoker chimneys along the East Pacific Rise. A diverse, yet phylogenetically constrained episymbiotic community is obligately associated with its dorsal surface. The morphologically and phylogenetically distinct dominant episymbionts have not yet been cultured, and there are no clearly defined roles for these bacteria in this symbiosis. A large insert fosmid library was screened for the presence of the two dominant phylotypes. Two fosmids, 35.2 and 38 kb, containing phylotype-specific 16S ribosmal DNA sequences were fully sequenced. Each fosmid had a gene encoding ATP citrate lyase, a key enzyme in the reverse tricarboxylic acid (rTCA) cycle, a CO2 fixation pathway. A selection of episymbiont communities from various geographic locations and <span class="hlt">vent</span> <span class="hlt">sites</span> were screened for the presence, diversity, and expression (via reverse transcription-PCR) of the ATP citrate lyase gene. Our results indicate that the ATP citrate lyase gene is not only a consistent presence in these episymbiont communities but is also expressed. Phylogenetically distinct forms of ATP citrate lyase were also found associated with and expressed by bacteria extracted from the tubes of A. pompejana. Utilizing PCR with degenerate primers based on a second key enzyme in the rTCA cycle, 2-oxoglutarate:acceptor oxidoreductase, we also demonstrated the persistent presence and expression of this gene in the episymbiont community. Our results suggest that members of both the episymbiont and the surrounding free-living communities display a chemolithoautotrophic form of growth and therefore contribute fixed carbon to other organisms in the <span class="hlt">vent</span> community. PMID:12957888</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.B12A0760C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.B12A0760C"><span id="translatedtitle">The Majority of Free-Living Autotrophic Bacteria use the Reductive TCA Cycle for Carbon Fixation at Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Campbell, B. J.; Cary, C.</p> <p>2003-12-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> support large micro and macroscopic communities, without the input of photosynthesis. Autotrophic production at these <span class="hlt">vents</span> is based on <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluid chemistry. Primary production has been thought to occur mainly via hydrogen sulfide oxidation through the Calvin-Benson pathway, as measured by the presence of Rubisco in endosymbionts of several invertebrate hosts. Recently, we characterized two fosmids from a large insert library of the epsilon Proteobacterial episymbionts of Alvinella pompejana. Both contained sequences encoding ATP citrate lyase, a key enzyme in the reverse TCA cycle, an alternate carbon dioxide fixation pathway. Previous investigators have demonstrated the dominance of the epsilon subdivision in the free-living bacterial communities at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Based on these results, our working hypothesis is: The rTCA cycle is the dominant pathway for carbon fixation in the free-living bacterial communities at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. A selection of free-living bacterial communities from various geographic locations (9N, East Pacific Rise and Guaymas Basin) were screened for the presence, diversity and expression (via RT-PCR) of Rubisco (forms I and II) and ATP citrate lyase. Our results indicate that the ATP citrate lyase gene is diverse and is consistently expressed in several types of <span class="hlt">vent</span> communities. The two forms of Rubisco are not consistently present or expressed in the same environments. These results indicate that chemoautotrophic production in the free-living bacterial communities at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> is dominated by bacteria that utilize the rTCA cycle, and parallels the phylogenetic dominance of members of the epsilon subdivision of Proteobacteria.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS51E..07G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS51E..07G"><span id="translatedtitle">From Mantle to Microbe to Mollusc: How Animal-Microbial Symbioses Influence Carbon and Sulfur Cycling in <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Flows.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Girguis, P. R.; Beinart, R.</p> <p>2014-12-01</p> <p>Symbioses between animals and chemoautotrophic bacteria dominate many <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. In these associations, symbiotic bacteria harness energy and "fix" carbon from the oxidation of reduced chemicals such as sulfide, methane, and hydrogen that are found in <span class="hlt">venting</span> fluids. At <span class="hlt">vents</span> along the Eastern Lau Spreading Center (ELSC) in the South Pacific, snails and mussels with chemoautotrophic symbionts have been shown to harness energy via the oxidation of sulfide. However, partially oxidized sulfur species such as thiosulfate and polysulfides have also been detected in abundance in their habitats. No studies to date have established whether thiosulfate or other partially oxidized sulfur compounds are used by these symbiotic associations, nor have studies constrained the potential role that symbioses might play in sulfur biogeochemical cycles at diffuse <span class="hlt">vent</span> flows. To address these questions, we used high-pressure, flow through incubations to study three symbiotic molluscs from the ELSC - the snails Alviniconcha and Ifremeria nautilei and the mussel Bathymodiolus brevior - at conditions mimicking those in situ. Via the use of isotopically labeled inorganic carbon, shipboard mass spectrometry and voltammetric microelectrodes, we quantified the production and consumption of different sulfur compounds by each of these symbioses. We established that the uptake and oxidation of either sulfide or thiosulfate could -to varying degrees- support carbon fixation in all three species. Notably, we also observed that some symbioses excreted thiosulfate and polysulfides under sulfidic conditions, suggesting that these symbioses are a source of partially oxidized sulfur species in the environment. We further observed spatial disparity in the carbon fixation rates among the individuals in our incubations that have implications for the variability of productivity in situ.Collectively, these data reveal that thiosulfate can support net autotrophy, and may be an ecologically important energy source for <span class="hlt">vent</span> symbioses. Furthermore, symbioses-mediated sulfur transformations may influence the ecology of the free-living community by governing the production and consumption of reduced sulfur species in this habitat.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25234397','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25234397"><span id="translatedtitle">High sulfate reduction efficiency in a UASB using an alternative source of sulfidogenic sludge derived from <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> sediments.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>García-Solares, Selene Montserrat; Ordaz, Alberto; Monroy-Hermosillo, Oscar; Jan-Roblero, Janet; Guerrero-Barajas, Claudia</p> <p>2014-12-01</p> <p>Sulfidogenesis in reactors is mostly achieved through adaptation of predominantly methanogenic granular sludge to sulfidogenesis. In this work, an upflow anaerobic sludge blanket (UASB) reactor operated under sulfate-reducing conditions was inoculated with <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> sediments to carry out sulfate reduction using volatile fatty acids (VFAs) as substrate and chemical oxygen demand (COD)/SO4 (-2) ratios between 0.49 and 0.64. After a short period of adaptation, a robust non-granular sludge was capable of achieving high sulfate reduction efficiencies while avoiding competence with methanogens and toxicity to the microorganisms due to high sulfide concentration. The highest sulfide concentration (2,552 mg/L) was obtained with acetate/butyrate, and sulfate reduction efficiencies were up to 98 %. A mixture of acetate/butyrate, which produced a higher yielding of HS(-), was preferred over acetate/propionate/butyrate since the consumption of COD was minimized during the process. Sludge was analyzed, and some of the microorganisms identified in the sludge belong to the genera Desulfobacterium, Marinobacter, and Clostridium. The tolerance of the sludge to sulfide may be attributed to the syntrophy among these microorganisms, some of which have been reported to tolerate high concentrations of sulfide. To the best of our knowledge, this is the first report on the analysis of the direct utilization of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> sediments as an alternate source of sludge for sulfate reduction under high sulfide concentrations. PMID:25234397</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS21B1142W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS21B1142W"><span id="translatedtitle">Development and field application of a 6-bottle serial gas-tight fluid sampler for collecting seafloor cold seep and <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids with autonomous operation capability</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, S.; Ding, K.; Yang, C.; Seyfried, W. E., Jr.; Tan, C.; Schaen, A. T.; Luhmann, A. J.</p> <p>2014-12-01</p> <p>A 6-bottle serial gas-tight sampler (so-called "six-shooter") was developed for application with deep-sea <span class="hlt">vent</span> fluids. The new device is composed of a custom-made 6-channel valve manifold and six sampling bottles which are circularly distributed around the valve manifold. Each valve channel consists of a high-pressure titanium cartridge valve and a motor-driven actuator. A sampling snorkel is connected to the inlet of the manifold that delivers the incoming fluid to different bottles. Each sampling bottle has a 160 ml-volume chamber and an accumulator chamber inside where compressed nitrogen is used to maintain the sample at near in-situ pressure. An electronics chamber that is located at the center of the sampler is used to carry out all sampling operations, autonomously, if desired. The sampler is of a compact circular configuration with a diameter of 26 cm and a length of 54 cm. During the SVC cruise AT 26-12, the sampler was deployed by DSV2 Alvin at a cold seep <span class="hlt">site</span> MC036 with a depth of 1090 m in the Gulf of Mexico. The sampler collected fluid samples automatically following the tidal cycle to monitor the potential impact of the tide cycle on the fluid chemistry of cold seep in a period of two day. During the cruise AT 26-17, the sampler was used with newly upgraded DSV2 Alvin three times at the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> along Axial Seamount and Main Endeavor Field on Juan de Fuca Ridge. During a 4-day deployment at Anemone diffuse <span class="hlt">site</span> (Axial Caldera), the sampler was set to work in an autonomous mode to collect fluid samples according to the preset interval. During other dives, the sampler was manually controlled via ICL (Inductively Coupled Link) communication through the hull. Gas-tight fluid samples were collected from different <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> with temperatures between 267 ? and 335 ? at the depth up to 2200 m. The field results indicate unique advantages of the design. It can be deployed in extended time period with remote operation or working autonomously taking gas-tight fluid samples. If used with HOV or ROV, it will reduce basket space occupation and ICL communication cables compared to traditional single-bottle gas-tight samplers. This time serial gas-tight fluid sampler will be further developed into a 36 bottle system for remote operation with seafloor cabled observatory.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=99708','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=99708"><span id="translatedtitle">Spatial Heterogeneity of Bacterial Populations along an Environmental Gradient at a Shallow Submarine <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> near Milos Island (Greece)</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sievert, Stefan M.; Brinkhoff, Thorsten; Muyzer, Gerard; Ziebis, Wiebke; Kuever, Jan</p> <p>1999-01-01</p> <p>The spatial heterogeneity of bacterial populations at a shallow-water <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> in the Aegean Sea close to the island of Milos (Greece) was examined at two different times by using acridine orange staining for total cell counts, cultivation-based techniques, and denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rRNA gene fragments. Concurrent with measurements of geochemical parameters, samples were taken along a transect from the center of the <span class="hlt">vent</span> to the surrounding area. Most-probable-number (MPN) counts of metabolically defined subpopulations generally constituted a minor fraction of the total cell counts; both counting procedures revealed the highest cell numbers in a transition zone from the strongly <span class="hlt">hydrothermally</span> influenced sediments to normal sedimentary conditions. Total cell counts ranged from 3.2 × 105 cells ml?1 in the water overlying the sediments to 6.4 × 108 cells g (wet weight) of sediment?1. MPN counts of chemolithoautotrophic sulfur-oxidizing bacteria varied between undetectable and 1.4 × 106 cells g?1. MPN counts for sulfate-reducing bacteria and dissimilatory iron-reducing bacteria ranged from 8 to 1.4 × 105 cells g?1 and from undetectable to 1.4 × 106 cells g?1, respectively. DGGE revealed a trend from a diverse range of bacterial populations which were present in approximately equal abundance in the transition zone to a community dominated by few populations close to the center of the <span class="hlt">vent</span>. Temperature was found to be an important parameter in determining this trend. However, at one sampling time this trend was not discernible, possibly due to storm-induced disturbance of the upper sediment layers. PMID:10473383</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3633350','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3633350"><span id="translatedtitle">Free-living bacterial communities associated with tubeworm (Ridgeia piscesae) aggregations in contrasting diffuse flow <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> habitats at the Main Endeavour Field, Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Forget, Nathalie L; Kim Juniper, S</p> <p>2013-01-01</p> <p>We systematically studied free-living bacterial diversity within aggregations of the vestimentiferan tubeworm Ridgeia piscesae sampled from two contrasting flow regimes (High Flow and Low Flow) in the Endeavour <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> Marine Protected Area (MPA) on the Juan de Fuca Ridge (Northeast Pacific). Eight samples of particulate detritus were recovered from paired tubeworm grabs from four <span class="hlt">vent</span> <span class="hlt">sites</span>. Most sequences (454 tag and Sanger methods) were affiliated to the Epsilonproteobacteria, and the sulfur-oxidizing genus Sulfurovum was dominant in all samples. Gammaproteobacteria were also detected, mainly in Low Flow sequence libraries, and were affiliated with known methanotrophs and decomposers. The cooccurrence of sulfur reducers from the Deltaproteobacteria and the Epsilonproteobacteria suggests internal sulfur cycling within these habitats. Other phyla detected included Bacteroidetes, Actinobacteria, Chloroflexi, Firmicutes, Planctomycetes, Verrucomicrobia, and Deinococcus–Thermus. Statistically significant relationships between sequence library composition and habitat type suggest a predictable pattern for High Flow and Low Flow environments. Most sequences significantly more represented in High Flow libraries were related to sulfur and hydrogen oxidizers, while mainly heterotrophic groups were more represented in Low Flow libraries. Differences in temperature, available energy for metabolism, and stability between High Flow and Low Flow habitats potentially explain their distinct bacterial communities. PMID:23401293</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25774156','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25774156"><span id="translatedtitle">Colonization of plant substrates at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> and cold seeps in the northeast Atlantic and Mediterranean and occurrence of symbiont-related bacteria.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Szafranski, Kamil M; Deschamps, Philippe; Cunha, Marina R; Gaudron, Sylvie M; Duperron, Sébastien</p> <p>2015-01-01</p> <p>Reducing conditions with elevated sulfide and methane concentrations in ecosystems such as <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, cold seeps or organic falls, are suitable for chemosynthetic primary production. Understanding processes driving bacterial diversity, colonization and dispersal is of prime importance for deep-sea microbial ecology. This study provides a detailed characterization of bacterial assemblages colonizing plant-derived substrates using a standardized approach over a geographic area spanning the North-East Atlantic and Mediterranean. Wood and alfalfa substrates in colonization devices were deployed for different periods at 8 deep-sea chemosynthesis-based <span class="hlt">sites</span> in four distinct geographic areas. Pyrosequencing of a fragment of the 16S rRNA-encoding gene was used to describe bacterial communities. Colonization occurred within the first 14 days. The diversity was higher in samples deployed for more than 289 days. After 289 days, no relation was observed between community richness and deployment duration, suggesting that diversity may have reached saturation sometime in between. Communities in long-term deployments were different, and their composition was mainly influenced by the geographical location where devices were deployed. Numerous sequences related to horizontally-transmitted chemosynthetic symbionts of metazoans were identified. Their potential status as free-living forms of these symbionts was evaluated based on sequence similarity with demonstrated symbionts. Results suggest that some free-living forms of metazoan symbionts or their close relatives, such as Epsilonproteobacteria associated with the shrimp Rimicaris exoculata, are efficient colonizers of plant substrates at <span class="hlt">vents</span> and seeps. PMID:25774156</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4343019','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4343019"><span id="translatedtitle">Colonization of plant substrates at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> and cold seeps in the northeast Atlantic and Mediterranean and occurrence of symbiont-related bacteria</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Szafranski, Kamil M.; Deschamps, Philippe; Cunha, Marina R.; Gaudron, Sylvie M.; Duperron, Sébastien</p> <p>2015-01-01</p> <p>Reducing conditions with elevated sulfide and methane concentrations in ecosystems such as <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, cold seeps or organic falls, are suitable for chemosynthetic primary production. Understanding processes driving bacterial diversity, colonization and dispersal is of prime importance for deep-sea microbial ecology. This study provides a detailed characterization of bacterial assemblages colonizing plant-derived substrates using a standardized approach over a geographic area spanning the North-East Atlantic and Mediterranean. Wood and alfalfa substrates in colonization devices were deployed for different periods at 8 deep-sea chemosynthesis-based <span class="hlt">sites</span> in four distinct geographic areas. Pyrosequencing of a fragment of the 16S rRNA-encoding gene was used to describe bacterial communities. Colonization occurred within the first 14 days. The diversity was higher in samples deployed for more than 289 days. After 289 days, no relation was observed between community richness and deployment duration, suggesting that diversity may have reached saturation sometime in between. Communities in long-term deployments were different, and their composition was mainly influenced by the geographical location where devices were deployed. Numerous sequences related to horizontally-transmitted chemosynthetic symbionts of metazoans were identified. Their potential status as free-living forms of these symbionts was evaluated based on sequence similarity with demonstrated symbionts. Results suggest that some free-living forms of metazoan symbionts or their close relatives, such as Epsilonproteobacteria associated with the shrimp Rimicaris exoculata, are efficient colonizers of plant substrates at <span class="hlt">vents</span> and seeps. PMID:25774156</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMED41C..04D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMED41C..04D"><span id="translatedtitle">CAREER: <span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> flow and temperature fluctuations: exploring long-term variability through an integrated research and education program</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Di Iorio, D.</p> <p>2011-12-01</p> <p>An acoustic scintillation system was built in partnership with ASL Environmental Sciences (Sidney BC Canada), which provided a unique opportunity for two engineering undergraduate students to live and work abroad. The acoustic instrumentation was tested in coastal waters and then deployed to study deep-sea <span class="hlt">hydrothermal</span> plume dynamics. Undergraduate students were involved in the deployment of instrumentation and the development of processing software to give vertical velocities and temperature fluctuations from a vigorous <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>. A graduate student thesis has yielded insights into the vertical and azimuthal dependence of entrainment and into plume bending and rise height. Teachers and Ocean Science Bowl students also participated in research cruises describing physical oceanography of estuaries, coastal waters, and deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> and participated in data collection, processing and analysis. Teachers used the knowledge they gained to develop creative educational curricula at their schools, to present their experiences at national conferences and to publish an article in the National Science Teachers Association - The Science Journal. One of the teachers was recently recognized with the Presidential Award for Excellence in Mathematics and Science Teaching. Working with the ocean bowl team at Oconee County High School has led to top ten placements in the national championships in 2005 (fourth place) and 2006 (sixth place). In order to increase quantitative methods in an undergraduate class, students acquire data from an ocean observatory and analyze the data for specific quantities of interest. One such project led to the calculation of the upper ocean heat content for the Greenland Sea using 7 years of Argo profiles, which showed a 0.04oC/year trend. These results were then published in JGR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1389273','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1389273"><span id="translatedtitle">Group-Specific 16S rRNA-Targeted Oligonucleotide Probes To Identify Thermophilic Bacteria in Marine <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Harmsen, H.; Prieur, D.; Jeanthon, C.</p> <p>1997-01-01</p> <p>Four 16S rRNA-targeted oligonucleotide probes were designed for the detection of thermophilic members of the domain Bacteria known to thrive in marine <span class="hlt">hydrothermal</span> systems. We developed and characterized probes encompassing most of the thermophilic members of the genus Bacillus, most species of the genus Thermus, the genera Thermotoga and Thermosipho, and the Aquificales order. The temperature of dissociation of each probe was determined. Probe specificities to the target groups were demonstrated by whole-cell and dot blot hybridization against a collection of target and nontarget rRNAs. Whole-cell hybridizations with the specific probes were performed on cells extracted from <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimneys. One of the samples contained cells that hybridized to the probe specific to genera Thermotoga and Thermosipho. No positive signals could be detected in the samples tested with the probes whose specificities encompassed either the genus Thermus or the thermophilic members of the genus Bacillus. However, when simultaneous hybridizations with the probe specific to the order Aquificales and a probe specific to the domain Bacteria (R. I. Amann, B. Binder, R. J. Olson, S. W. Chisholm, R. Devereux, and D. A. Stahl, Appl. Environ. Microbiol. 56:1919-1925, 1990) were performed on cells extracted from the top and exterior subsamples of chimneys, positive signals were obtained from morphologically diverse bacteria representing about 40% of the bacterial population. Since specificity studies also revealed that the bacterial probe did not hybridize with the members of the order Aquificales, the detected cells may therefore correspond to a new type of bacteria. One of the observed morphotypes was similar to that of a strictly anaerobic autotrophic sulfur-reducing strain that we isolated from the chimney samples. This work demonstrates that application of whole-cell hybridization with probes specific for different phylogenetic levels is a useful tool for detailed studies of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> microbial ecology. PMID:16535717</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013DSRII..92..124M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013DSRII..92..124M"><span id="translatedtitle">Getting the bigger picture: Using precision Remotely Operated Vehicle (ROV) videography to acquire high-definition mosaic images of newly discovered <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the Southern Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marsh, Leigh; Copley, Jonathan T.; Huvenne, Veerle A. I.; Tyler, Paul A.; Isis ROV Facility</p> <p>2013-08-01</p> <p>Direct visual observations from submersible vehicles at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> typically only reveal a fraction of the <span class="hlt">vent</span> environment at any one time. We describe the use of precision Remotely Operated Vehicle (ROV) videography to produce extensive mosaic images of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimneys and surrounding seafloor areas (c. 250 m2), with sufficient resolution to determine distributions of macro- and megafauna. Doppler velocity log navigation (DVLNAV) was used to follow overlapping vertical survey lines in a fixed plane facing a <span class="hlt">vent</span> chimney, while acquiring high-definition video imagery using a forward-looking camera. The DVLNAV also enabled the vehicle to follow overlapping horizontal survey lines while acquiring seafloor imagery from a downward-looking video camera and mapping variations in seawater temperature. Digital stills images extracted from video were used to compile high-resolution composite views of the surveyed areas. Applying these image acquisition techniques at <span class="hlt">vent</span> fields on the East Scotia Ridge, Southern Ocean, revealed consistent patterns of faunal zonation around <span class="hlt">vent</span> sources, variations in proportions of faunal assemblage types on different faces of a <span class="hlt">vent</span> chimney, and differences in proportions of faunal assemblages between two different <span class="hlt">vent</span> fields. The technique can therefore be used to determine the composition and spatial distribution of fauna across complex areas of topography, such as <span class="hlt">vent</span> fields, where mosaic images of vertical structures cannot currently be acquired using other platforms such as autonomous underwater vehicles (AUVs). These image acquisition techniques, demonstrated here in the first ROV dives at newly discovered <span class="hlt">vent</span> fields, may offer an appropriate technology for rapid baseline studies required by the potential mining of seafloor massive sulfides (SMS).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004DSRI...51..225H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004DSRI...51..225H"><span id="translatedtitle">Testing biological control of colonization by vestimentiferan tubeworms at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> (East Pacific Rise, 9°50'N)1</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hunt, Heather L.; Metaxas, Anna; Jennings, Robert M.; Halanych, Kenneth M.; Mullineaux, Lauren S.</p> <p>2004-02-01</p> <p>Three species of vestimentiferans are found at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the East Pacific Rise (EPR). Tevnia jerichonana is an early colonist and Riftia pachyptila has the greatest biomass in established <span class="hlt">vent</span> assemblages, but the role of Oasisia alvinae, a small species that occurs sporadically, is unknown. Anecdotal evidence suggests that O. alvinae may be abundant in the microhabitat underneath mussels. Previous studies have suggested that early T. jerichonana colonists may facilitate settlement of the late colonist R. pachyptila. To address potential mechanisms for the successional sequence and to explore the role of O. alvinae, we examined the effects of the presence of vestimentiferan ( R. pachyptila and T. jerichonana) tubes and mussel ( Bathymodiolus thermophilis) shell cover on recruitment of vestimentiferans on basalt blocks deployed at 9°50'N, 104°17'W on the EPR. A molecular assay was used to identify individuals to species since they were too small to be identified morphologically. Although colonists in both experiments belonged to all three species of vestimentiferans, only a few were T. jerichonana. Colonization of vestimentiferans did not increase in the presence of vestimentiferan tubes. The presence of mussel shell cover did not influence the proportions of R. pachyptila and O. alvinae, or the total number of colonists. Because the experimental blocks in this study were placed within dense clumps of R. pachyptila, we suggest that, while T. jerichonana may be an important cue for vestimentiferans settling at new <span class="hlt">vents</span>, adult R. pachyptila also can act as a settlement cue for larvae. O. alvinae colonists were abundant in all of the treatments in our experiments, indicating that, although adults of this species are apparently rare at these <span class="hlt">sites</span>, O. alvinae can settle in abundance if a suitable micro-environment is available.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.B43G0497A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.B43G0497A"><span id="translatedtitle">Distribution, activity and function of short-chain alkane degrading phylotypes in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> sediments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adams, M. M.; Joye, S. B.; Hoarfrost, A.; Girguis, P. R.</p> <p>2012-12-01</p> <p>Global geochemical analyses suggest that C2-C4 short chain alkanes are a common component of the utilizable carbon pool in deep-sea sediments worldwide and have been found in diverse ecosystems. From a thermodynamic standpoint, the anaerobic microbial oxidation of these aliphatic hydrocarbons is more energetically yielding than the anaerobic oxidation of methane (AOM). Therefore, the preferential degradation of these hydrocarbons may compete with AOM for the use of oxidants such as sulfate, or other potential oxidants. Such processes could influence the fate of methane in the deep-sea. Sulfate-reducing bacteria (SRB) from hydrocarbon seep sediments of the Gulf of Mexico and Guaymas Basin have previously been enriched that anaerobically oxidize short chain alkanes to generate CO2 with the preferential utilization of 12C-enriched alkanes (Kniemeyer et al. 2007). Different temperature regimens along with multiple substrates were tested and a pure culture (deemed BuS5) was isolated from mesophilic enrichments with propane or n-butane as the sole carbon source. Through comparative sequence analysis, strain BuS5 was determined to cluster with the metabolically diverse Desulfosarcina / Desulfococcus cluster, which also contains the SRB found in consortia with anaerobic, methane-oxidizing archaea in seep sediments. Enrichments from a terrestrial, low temperature sulfidic hydrocarbon seep also corroborated that propane degradation occurred with most bacterial phylotypes surveyed belonging to the Deltaproteobacteria, particularly Desulfobacteraceae (Savage et al. 2011). To date, no microbes capable of ethane oxidation or anaerobic C2-C4 alkane oxidation at thermophilic temperature have been isolated. The sediment-covered, <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems found at Middle Valley (Juan de Fuca Ridge, eastern Pacific Ocean) are a prime environment for investigating mesophilic to thermophilic anaerobic oxidation of short-chain alkanes, given the elevated temperatures and dissolved hydrocarbon species characteristic of these metalliferous sediments. These systems are also characterized by sharp physicochemical gradients that have been shown to have a pronounced effect on microbial ecology and activity. Sediments were collected from a Middle Valley field with relatively high concentrations of short-chain alkanes and incubated in anaerobic batch reactors with each individual alkane (C1, C2, C3 and C4, respectively) at a range of temperatures (25, 55 and 75 °C) to mimic environmental physico-chemical conditions in a closed system. Stable carbon isotope ratios and radiotracer incubations provide clear evidence for C2-C4 alkane oxidation in the sediments over time. Upon identifying sediments with anaerobic alkane oxidation activity, microbial communities were screened via 16S rRNA pyrosequencing, and key phylotypes were then quantified using both molecular and microscopic methods. There were shifts in overall community composition and putative alkane-oxidizing phylotypes after the incubation period with the alkane substrates. These are the first evidence to date indicating that anaerobic C2-C4 alkane oxidation occurs across a broad range of temperatures in metalliferous sediments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008epsc.conf..115L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008epsc.conf..115L"><span id="translatedtitle">Morphology of cone-fields in SW Elysium Planitia - Traces of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> on Mars?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lanz, J. K.; Saric, M. B.</p> <p>2008-09-01</p> <p>Introduction Small cone-shaped features with summit pits can be found in several regions on Mars; mainly in Isidis Planitia; Elysium Planitia; Amazonis Planitia; Acidalia Planitia; in the Cydonia Region; in Cerberus Planum; the Phlegra Montes and on several volcanic flanks. They vary greatly in size and morphology and have been compared to terrestrial features of various origins; namely (1) cinder cones (e.g. [1]), (2) tuff cones or tuff rings (e.g. [2]), (3) rootless cones (pseudocraters) (e.g. [3], [4]), (4) pingos (e.g. [5], [6]) and (5) mud volcanoes (e.g. [7]). They are often found near volcanic centers and large lava fields or cluster in regions where the volatile content of the Martian regolith was/is supposedly high. This has led to the assumption that (ground-) water or ground ice was a trigger or driving force of cone formation. They could therefore, be an important indicator of the history of water on the planet. We have studied an area in western Elysium Planitia, bordering the Aeolis Planum plateau, which exhibits a large number of pitted cones, ridges and dome-like structures. Their distribution and morphology differs strongly from pitted cones elsewhere in Elysium Planitia, which have mainly been interpreted as hydrovolcanic rootless cones, and from other regions on Mars. Based on our observations, we present an alternative model for cone formation in the study area that might hint towards <span class="hlt">hydrothermal</span> processes in the Aeolis Planum region and possibly young igneous activity. Aeolis Planum Cones The Aeolis Planum pitted cones (referred to as APCs from now on) cluster along the southern edges of the broad shallow valley that borders the Aeolis Planum Formation (APF) to the north. Cones along the northern edges of the valley are rare and can only be found in association with APF remnants where they strongly resemble the cones in the south. Along the southern border the cone coverage is almost continuous, describing a narrow band approximately 2 to 3 km wide. There are distinct morphological changes both within the band from north to south and along the band from east to west (Fig. 2). The cones are mostly circular but elongated, irregular forms are common. They are of varying size with basal diameters ranging from 20 to 200 meters, though most (single) cones have basal diameters below 100 meters. The heights of the cones are difficult to determine as their sizes are far below the resolution limits of either MOLA or HRSC stereo data, yet photoclinometric calculations have given approximate heights between ~ 10 up to several dozens of meters. Often the cones show hardly any elevation above the surroundings (e.g. Fig. 2c, e or f). Most of the APCs have steep convex flanks and large summit pits with diameters at least half as wide as their bases. The overall morphology of the cones changes from S to N with distance from the APF and from E to W along the edges of the APF. Toward the south, close to the strongly eroded borders of the APF, broad ridges and elongated domes are dominant. They form a narrow band approximately 2 km wide. The ridges and domes are a few dozen to several hundred meters long and between 10 to 50 meters wide and show numerous cracks and fissures. They are often topped by small cones, elongated pits and remnants of APF sediments. Further north follows a rather abrupt transition from the ridged area to more cone-dominated regions. Here single cones are prevalent with a more random distribution. Their number decreases rapidly with increasing distance from the APF and approximately 3 km off the southern edge of the APF no further cones are found. <span class="hlt">Hydrothermal</span> <span class="hlt">venting</span> on Mars? Morphology and stratigraphic relationships indicate that the cones are young and that they have, at least in places, developed inside the APF complex. APF remnants can be found covering the central pits of cones and APF units have been tilted and eroded by coneforming processes. Furthermore, cones are mainly found inside a narrow band 2-3 km wide along the APF-lava contact. A connection between APF-lava interaction and con</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5479860','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5479860"><span id="translatedtitle">Beryllium 10 in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> deposits from the East Pacific Ridges: Role of sediments in the <span class="hlt">hydrothermal</span> processes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Valette-Silver, J.N.; Tera, F.; Klein, J.; Middleton, R.</p> <p>1987-10-10</p> <p>Beryllium 10 concentrations were determined for 31 handpicked <span class="hlt">hydrothermal</span> sulfides, six oxyhydroxides, seven basalts, and five sediments collected from the <span class="hlt">hydrothermally</span> active areas of the East Pacific ridges. The samples includes specimens from the East Pacific Rise (EPR) at 21 /sup 0/N and 13 /sup 0/N, the Galapagos Rift, the Guaymas Basin, and the Gorda and the Juan de Fuca ridges. Additional samples from massive sulfides associated with the Oman ophiolites were studied. In all samples, we obtained values ranging from 0.04 x 10/sup 6/ atoms/g to 125 x 10/sup 6/ atoms/g, with the lowest values being very close to our blank (0.015 x 10/sup 6/ atoms/g). The data show systematic variations with sample location and type. The /sup 10/Be concentrations measured for the mid-ocean basalts are of the order of 0.3 x 10/sup 6/ atoms/g and reach 3800 x 10/sup 6/ atoms/g for the pelagic deep-sea sediments collected near the EPR 21 /sup 0/N. Based on their /sup 10/Be concentrations, we can clearly distinguish two categories of sulfides: sulfides containing low /sup 10/Be concentration (<10 /sup 6/ atoms/g) sitting directly on the mid-ocean basalt (EPR of Juan de Fuca), and sulfides with high /sup 10/Be concentration (>10/sup 6/ atoms/g) located atop of a thick pile of young sediments (Guaymas Basin or Gorda Ridge).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26332260','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26332260"><span id="translatedtitle">Thermoelectricity Generation and Electron-Magnon Scattering in a Natural Chalcopyrite Mineral from a Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ang, Ran; Khan, Atta Ullah; Tsujii, Naohito; Takai, Ken; Nakamura, Ryuhei; Mori, Takao</p> <p>2015-10-26</p> <p>Current high-performance thermoelectric materials require elaborate doping and synthesis procedures, particularly in regard to the artificial structure, and the underlying thermoelectric mechanisms are still poorly understood. Here, we report that a natural chalcopyrite mineral, Cu1+x Fe1-x S2 , obtained from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> can directly generate thermoelectricity. The resistivity displayed an excellent semiconducting character, and a large thermoelectric power and high power factor were found in the low x region. Notably, electron-magnon scattering and a large effective mass was detected in this region, thus suggesting that the strong coupling of doped carriers and antiferromagnetic spins resulted in the natural enhancement of thermoelectric properties during mineralization reactions. The present findings demonstrate the feasibility of thermoelectric energy generation and electron/hole carrier modulation with natural materials that are abundant in the Earth's crust. PMID:26332260</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.B12B..03M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.B12B..03M"><span id="translatedtitle">Constraints on hydrocarbon and organic acid abundances in <span class="hlt">hydrothermal</span> fluids at the Von Damm <span class="hlt">vent</span> field, Mid-Cayman Rise (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McDermott, J. M.; Seewald, J.; German, C. R.; Sylva, S. P.</p> <p>2013-12-01</p> <p>The generation of organic compounds in <span class="hlt">vent</span> fluids has been of interest since the discovery of seafloor <span class="hlt">hydrothermal</span> systems, due to implications for the sustenance of present-day microbial populations and their potential role in the origin of life on early Earth. Possible sources of organic compounds in <span class="hlt">hydrothermal</span> systems include microbial production, thermogenic degradation of organic material, and abiotic synthesis. Abiotic organic synthesis reactions may occur during active circulation of seawater-derived fluids through the oceanic crust or within olivine-hosted fluid inclusions containing carbon-rich magmatic volatiles. H2-rich end-member fluids at the Von Damm <span class="hlt">vent</span> field on the Mid-Cayman Rise, where fluid temperatures reach 226°C, provide an exciting opportunity to examine the extent of abiotic carbon transformations in a highly reducing system. Our results indicate multiple sources of carbon compounds in <span class="hlt">vent</span> fluids at Von Damm. An ultramafic-influenced <span class="hlt">hydrothermal</span> system located on the Mount Dent oceanic core complex at 2350 m depth, Von Damm <span class="hlt">vent</span> fluids contain H2, CH4, and C2+ hydrocarbons in high abundance relative to basalt-hosted <span class="hlt">vent</span> fields, and in similar abundance to other ultramafic-hosted systems, such as Rainbow and Lost City. The CO2 content and isotopic composition in end-member fluids are virtually identical to bottom seawater, suggesting that seawater DIC is unchanged during <span class="hlt">hydrothermal</span> circulation of seawater-derived fluids. Accordingly, end-member CH4 that is present in slightly greater abundance than CO2 cannot be generated from reduction of aqueous CO2 during <span class="hlt">hydrothermal</span> circulation. We postulate that CH4 and C2+ hydrocarbons that are abundantly present in Von Damm <span class="hlt">vent</span> fluids reflect leaching of fluids from carbon- and H2-rich fluid inclusions hosted in plutonic rocks. Geochemical modeling of carbon speciation in the Von Damm fluids suggests that the relative abundances of CH4, C2+ hydrocarbons, and CO2 are consistent with thermodynamic equilibrium at higher temperatures and more reducing conditions than those observed in the Von Damm <span class="hlt">vent</span> fluids. These findings are consistent with a scenario in which n-alkanes form abiotically within a high-H2, carbon-rich olivine-hosted fluid inclusion, and are subsequently liberated and transported to the seafloor during <span class="hlt">hydrothermal</span> alteration of the lower crustal rocks exposed at the Mount Dent oceanic core complex. Mixed fluids at Von Damm show depletions in CO2 and H2, relative to conservative mixing. Multiple S isotope measurements indicate that the H2 sink cannot be attributed to sulfate reduction. Thermodynamic constraints indicate that high-H2 conditions support the active formation of formate via reduction of dissolved CO2 during <span class="hlt">hydrothermal</span> circulation - a process that has also been described at the Lost City <span class="hlt">vent</span> field - and could account for the concurrent depletions in CO2 and H2. The transformation of inorganic carbon to organic compounds via two distinct pathways in modern seafloor <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> validates theoretical and experimental conceptual models regarding processes occurring in the crust and during <span class="hlt">hydrothermal</span> circulation, and is relevant to supporting life in <span class="hlt">vent</span> ecosystems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4393452','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4393452"><span id="translatedtitle">Quantitative PCR Analysis of Functional Genes in Iron-Rich Microbial Mats at an Active <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> System (L?'ihi Seamount, Hawai'i)</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jesser, Kelsey J.; Fullerton, Heather; Hager, Kevin W.</p> <p>2015-01-01</p> <p>The chemolithotrophic Zetaproteobacteria represent a novel class of Proteobacteria which oxidize Fe(II) to Fe(III) and are the dominant bacterial population in iron-rich microbial mats. Zetaproteobacteria were first discovered at L?'ihi Seamount, located 35 km southeast off the big island of Hawai'i, which is characterized by low-temperature diffuse <span class="hlt">hydrothermal</span> <span class="hlt">venting</span>. Novel nondegenerate quantitative PCR (qPCR) assays for genes associated with microbial nitrogen fixation, denitrification, arsenic detoxification, Calvin-Benson-Bassham (CBB), and reductive tricarboxylic acid (rTCA) cycles were developed using selected microbial mat community-derived metagenomes. Nitrogen fixation genes were not detected, but all other functional genes were present. This suggests that arsenic detoxification and denitrification processes are likely cooccurring in addition to two modes of carbon fixation. Two groups of microbial mat community types were identified by terminal restriction fragment length polymorphism (T-RFLP) and were further described based on qPCR data for zetaproteobacterial abundance and carbon fixation mode preference. qPCR variance was associated with mat morphology but not with temperature or sample <span class="hlt">site</span>. Geochemistry data were significantly associated with sample <span class="hlt">site</span> and mat morphology. Together, these qPCR assays constitute a functional gene signature for iron microbial mat communities across a broad array of temperatures, mat types, chemistries, and sampling <span class="hlt">sites</span> at L?'ihi Seamount. PMID:25681182</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25681182','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25681182"><span id="translatedtitle">Quantitative PCR analysis of functional genes in iron-rich microbial mats at an active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> system (L?'ihi Seamount, Hawai'i).</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jesser, Kelsey J; Fullerton, Heather; Hager, Kevin W; Moyer, Craig L</p> <p>2015-05-01</p> <p>The chemolithotrophic Zetaproteobacteria represent a novel class of Proteobacteria which oxidize Fe(II) to Fe(III) and are the dominant bacterial population in iron-rich microbial mats. Zetaproteobacteria were first discovered at L?'ihi Seamount, located 35 km southeast off the big island of Hawai'i, which is characterized by low-temperature diffuse <span class="hlt">hydrothermal</span> <span class="hlt">venting</span>. Novel nondegenerate quantitative PCR (qPCR) assays for genes associated with microbial nitrogen fixation, denitrification, arsenic detoxification, Calvin-Benson-Bassham (CBB), and reductive tricarboxylic acid (rTCA) cycles were developed using selected microbial mat community-derived metagenomes. Nitrogen fixation genes were not detected, but all other functional genes were present. This suggests that arsenic detoxification and denitrification processes are likely cooccurring in addition to two modes of carbon fixation. Two groups of microbial mat community types were identified by terminal restriction fragment length polymorphism (T-RFLP) and were further described based on qPCR data for zetaproteobacterial abundance and carbon fixation mode preference. qPCR variance was associated with mat morphology but not with temperature or sample <span class="hlt">site</span>. Geochemistry data were significantly associated with sample <span class="hlt">site</span> and mat morphology. Together, these qPCR assays constitute a functional gene signature for iron microbial mat communities across a broad array of temperatures, mat types, chemistries, and sampling <span class="hlt">sites</span> at L?'ihi Seamount. PMID:25681182</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21966922','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21966922"><span id="translatedtitle">Gamma- and epsilonproteobacterial ectosymbionts of a shallow-water marine worm are related to deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ectosymbionts.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ruehland, Caroline; Dubilier, Nicole</p> <p>2010-08-01</p> <p>The marine oligochaete worm Tubificoides benedii is often found in high numbers in eutrophic coastal sediments with low oxygen and high sulfide concentrations. A dense biofilm of filamentous bacteria on the worm's tail end were morphologically described over 20 years ago, but no further studies of these epibiotic associations were done. In this study, we used fluorescence in situ hybridization and comparative sequence analysis of 16S rRNA and protein-coding genes to characterize the microbial community of the worm's tail ends. The presence of genes involved in chemoautotrophy (cbbL and cbbM) and sulfur metabolism (aprA) indicated the potential of the T. benedii microbial community for chemosynthesis. Two filamentous ectosymbionts were specific to the worm's tail ends: one belonged to the Leucothrix mucor clade within the Gammaproteobacteria and the other to the Thiovulgaceae within the Epsilonproteobacteria. Both T. benedii ectosymbionts belonged to clades that consisted almost exclusively of bacteria associated with invertebrates from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Such close relationships between symbionts from shallow-water and deep-sea hosts that are not closely related to each other are unusual, and indicate that biogeography and host affiliation did not play a role in these associations. Instead, similarities between the dynamic environments of <span class="hlt">vents</span> and organic-rich mudflats with their strong fluctuations in reductants and oxidants may have been the driving force behind the establishment and evolution of these symbioses. PMID:21966922</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3136470','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3136470"><span id="translatedtitle">Linking <span class="hlt">Hydrothermal</span> Geochemistry to Organismal Physiology: Physiological Versatility in Riftia pachyptila from Sedimented and Basalt-hosted <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Robidart, Julie C.; Roque, Annelys; Song, Pengfei; Girguis, Peter R.</p> <p>2011-01-01</p> <p>Much of what is known regarding Riftia pachyptila physiology is based on the wealth of studies of tubeworms living at diffuse flows along the fast-spreading, basalt-hosted East Pacific Rise (EPR). These studies have collectively suggested that Riftia pachyptila and its chemoautotrophic symbionts are physiologically specialized, highly productive associations relying on hydrogen sulfide and oxygen to generate energy for carbon fixation, and the symbiont's nitrate reduction to ammonia for energy and biosynthesis. However, Riftia also flourish in sediment-hosted <span class="hlt">vents</span>, which are markedly different in geochemistry than basalt-hosted systems. Here we present data from shipboard physiological studies and global quantitative proteomic analyses of Riftia pachyptila trophosome tissue recovered from tubeworms residing in the EPR and the Guaymas basin, a sedimented, <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field. We observed marked differences in symbiont nitrogen metabolism in both the respirometric and proteomic data. The proteomic data further suggest that Riftia associations in Guaymas may utilize different sulfur compounds for energy generation, may have an increased capacity for energy storage, and may play a role in degrading exogenous organic carbon. Together these data reveal that Riftia symbionts are far more physiologically plastic than previously considered, and that -contrary to previous assertions- Riftia do assimilate reduced nitrogen in some habitats. These observations raise new hypotheses regarding adaptations to the geochemical diversity of habitats occupied by Riftia, and the degree to which the environment influences symbiont physiology and evolution. PMID:21779334</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AsBio...7..416L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AsBio...7..416L"><span id="translatedtitle">Microbial Diversity of Indian Ocean <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Plumes: Microbes Tolerant of Desiccation, Peroxide Exposure, and Ultraviolet and ?-Irradiation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>La Duc, Myron T.; Benardini, James N.; Kempf, Michael J.; Newcombe, David A.; Lubarsky, Michael; Venkateswaran, Kasthuri</p> <p>2007-05-01</p> <p>The microbial diversity of Kali chimney plumes, part of a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field in the Rodriguez Triple Junction, Indian Ocean (depth approximately 2,240 m), was examined in an attempt to discover ``extremotolerant'' microorganisms that have evolved unique resistance capabilities to this harsh environment. Water and sediment samples were collected from the <span class="hlt">vent</span> and from sediments located at various distances (2-20 m) away from and surrounding the chimney. Samples were screened for hypertolerant microbes that are able to withstand multiple stresses. A total of 46 isolates were selected for exposure to a number of perturbations, such as heat shock, desiccation, H2O2, and ultraviolet (UV) and ?-irradiation. The survival of Psychrobacter sp. L0S3S-03b following exposure to >1,000 J/m2 UV254 radiation was particularly intriguing amid a background of varying levels of resistance. Vegetative cells of this non-spore-forming microbe not only survived all of the treatments, but also exhibited a 90% lethal dose of 30 s when exposed to simulated martian UV radiation and a 100% lethal dose of 2 min when exposed to full spectrum UV, which is comparable to findings for bacterial endospores.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/392324','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/392324"><span id="translatedtitle">Probing the characteristics of metal- and sulfide-binding proteins in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> polychaetes using HPLC/IES-MS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Martineu, P.; Juniper, S.K.; Ikonomou, M.G.; Thompson, J.</p> <p>1995-12-31</p> <p>Alvinellids polychaetes colonizing the surfaces of black smokers from Eastern Pacific <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> occupy extreme environments with high levels of heavy metals and sulfide. Investigations of mechanisms that enable them to tolerate these extreme conditions indicate sulfide-binding capacity in the blood serum of Paralvinella palmiformis and accumulation of heavy metals in their tissues. A need to characterize metal-binding proteins lead the authors to improve purification and separation of metallothioneins (MTs) by reversed-phase liquid chromatography (RP-HPLC) on-line with electrospray mass spectrometry (ES/MS). A first separation step of small proteins from crude homogenates of worm tissues is performed on a size exclusion column following by accurate molecular weight identification with on-line LC-MS. This powerful technique has refined separation of isoform MT standards and weight characterization, and has provided an analytical tool to analyze metal-binding proteins from <span class="hlt">vent</span> polychaetes. The authors are also applying this technique to separation of sulfide-binding proteins in blood serum and to identify ligands involved in sulfide detoxication and transport.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013BGD....10.2675M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013BGD....10.2675M"><span id="translatedtitle">Finding immune gene expression differences induced by marine bacterial pathogens in the deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel Bathymodiolus azoricus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martins, E.; Queiroz, A.; Serrão Santos, R.; Bettencourt, R.</p> <p>2013-02-01</p> <p>The deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel Bathymodiolus azoricus lives in a natural environment characterized by extreme conditions of hydrostatic pressure, temperature, pH, high concentrations of heavy metals, methane and hydrogen sulphide. The deep-sea <span class="hlt">vent</span> biological systems represent thus the opportunity to study and provide new insights into the basic physiological principles that govern the defense mechanisms in <span class="hlt">vent</span> animals and to understand how they cope with microbial infections. Hence, the importance of understanding this animal's innate defense mechanisms, by examining its differential immune gene expressions toward different pathogenic agents. In the present study, B. azoricus mussels were infected with single suspensions of marine bacterial pathogens, consisting of Vibrio splendidus, Vibrio alginolyticus, or Vibrio anguillarum, and a pool of these Vibrio strains. Flavobacterium suspensions were also used as an irrelevant bacterium. Gene expression analyses were carried out using gill samples from animals dissected at 12 h and 24 h post-infection times by means of quantitative-Polymerase Chain Reaction aimed at targeting several immune genes. We also performed SDS-PAGE protein analyses from the same gill tissues. We concluded that there are different levels of immune gene expression between the 12 h and 24 h exposure times to various bacterial suspensions. Our results from qPCR demonstrated a general pattern of gene expression, decreasing from 12 h over 24 h post-infection. Among the bacteria tested, Flavobacterium is the microorganism species inducing the highest gene expression level in 12 h post-infections animals. The 24 h infected animals revealed, however, greater gene expression levels, using V. splendidus as the infectious agent. The SDS-PAGE analysis also pointed at protein profile differences between 12 h and 24 h, particularly around a protein area, of 18 KDa molecular mass, where most dissimilarities were found. Multivariate analyses demonstrated that immune genes, as well as experimental infections, clustered in discrete groups in accordance with the patterns observed in gene expression changes induced by bacterial pathogens.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013BGeo...10.7279M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013BGeo...10.7279M"><span id="translatedtitle">Finding immune gene expression differences induced by marine bacterial pathogens in the Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel Bathymodiolus azoricus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martins, E.; Queiroz, A.; Serrão Santos, R.; Bettencourt, R.</p> <p>2013-11-01</p> <p>The deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel Bathymodiolus azoricus lives in a natural environment characterised by extreme conditions of hydrostatic pressure, temperature, pH, high concentrations of heavy metals, methane and hydrogen sulphide. The deep-sea <span class="hlt">vent</span> biological systems represent thus the opportunity to study and provide new insights into the basic physiological principles that govern the defense mechanisms in <span class="hlt">vent</span> animals and to understand how they cope with microbial infections. Hence, the importance of understanding this animal's innate defense mechanisms, by examining its differential immune gene expressions toward different pathogenic agents. In the present study, B. azoricus mussels were infected with single suspensions of marine bacterial pathogens, consisting of Vibrio splendidus, Vibrio alginolyticus, or Vibrio anguillarum, and a pool of these Vibrio bacteria. Flavobacterium suspensions were also used as a non-pathogenic bacterium. Gene expression analyses were carried out using gill samples from infected animals by means of quantitative-Polymerase Chain Reaction aimed at targeting several immune genes. We also performed SDS-PAGE protein analyses from the same gill tissues. We concluded that there are different levels of immune gene expression between the 12 h to 24 h exposure times to various bacterial suspensions. Our results from qPCR demonstrated a general pattern of gene expression, decreasing from 12 h over 24 h post-infection. Among the bacteria tested, Flavobacterium is the bacterium inducing the highest gene expression level in 12 h post-infections animals. The 24 h infected animals revealed, however, greater gene expression levels, using V. splendidus as the infectious agent. The SDS-PAGE analysis also pointed at protein profile differences between 12 h and 24 h, particularly evident for proteins of 18-20 KDa molecular mass, where most dissimilarity was found. Multivariate analyses demonstrated that immune genes, as well as experimental infections, clustered in discrete groups in accordance with the gene expression patterns induced by bacterial pathogens.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25634941','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25634941"><span id="translatedtitle">Methanocaldococcus bathoardescens sp. nov., a hyperthermophilic methanogen isolated from a volcanically active deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stewart, Lucy C; Jung, Jong-Hyun; Kim, You-Tae; Kwon, Soon-Wo; Park, Cheon-Seok; Holden, James F</p> <p>2015-04-01</p> <p>A hyperthermophilic methanogen, strain JH146(T), was isolated from 26 °C <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluid emanating from a crack in basaltic rock at Marker 113 <span class="hlt">vent</span>, Axial Seamount in the northeastern Pacific Ocean. It was identified as an obligate anaerobe that uses only H2 and CO2 for growth. Phylogenetic analysis based on 16S rRNA gene sequences showed that the strain is more than 97% similar to other species of the genus Methanocaldococcus . Therefore, overall genome relatedness index analyses were performed to establish that strain JH146(T) represents a novel species. For each analysis, strain JH146(T) was most similar to Methanocaldococcus sp. FS406-22, which can fix N2 and also comes from Marker 113 <span class="hlt">vent</span>. However, strain JH146(T) differs from strain FS406-22 in that it cannot fix N2. The average nucleotide identity score for strain JH146(T) was 87%, the genome-to-genome direct comparison score was 33-55% and the species identification score was 93%. For each analysis, strain JH146(T) was below the species delineation cut-off. Full-genome gene synteny analysis showed that strain JH146(T) and strain FS406-22 have 97% genome synteny, but strain JH146(T) was missing the operons necessary for N2 fixation and assimilatory nitrate reduction that are present in strain FS406-22. Based on its whole genome sequence, strain JH146(T) is suggested to represent a novel species of the genus Methanocaldococcus for which the name Methanocaldococcus bathoardescens is proposed. The type strain is JH146(T) (?=?DSM 27223(T)?=?KACC 18232(T)). PMID:25634941</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.climategeology.ethz.ch/publications/2011_Dias_et_al.pdf','EPRINT'); return false;" href="http://www.climategeology.ethz.ch/publications/2011_Dias_et_al.pdf"><span id="translatedtitle">Geochemistry and stable isotope constraints on high-temperature activity from sediment cores of the Saldanha <span class="hlt">hydrothermal</span> field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Gilli, Adrian</p> <p></p> <p>of the Saldanha <span class="hlt">hydrothermal</span> field Á.S. Dias a, ,1 , G.L. Früh-Green b,1 , S.M. Bernasconi c,1 , F.J.A.S. Barriga <span class="hlt">hydrothermal</span> <span class="hlt">site</span> stable isotopes <span class="hlt">hydrothermal</span> calcite serpentinization heat source The Saldanha <span class="hlt">hydrothermal</span> centimeter-sized <span class="hlt">vents</span> without the formation of chimney structures. We present geochemical and stable isotope</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20228114','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20228114"><span id="translatedtitle">Biogeography and biodiversity in sulfide structures of active and inactive <span class="hlt">vents</span> at deep-sea <span class="hlt">hydrothermal</span> fields of the Southern Mariana Trough.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kato, Shingo; Takano, Yoshinori; Kakegawa, Takeshi; Oba, Hironori; Inoue, Kazuhiko; Kobayashi, Chiyori; Utsumi, Motoo; Marumo, Katsumi; Kobayashi, Kensei; Ito, Yuki; Ishibashi, Jun-ichiro; Yamagishi, Akihiko</p> <p>2010-05-01</p> <p>The abundance, diversity, activity, and composition of microbial communities in sulfide structures both of active and inactive <span class="hlt">vents</span> were investigated by culture-independent methods. These sulfide structures were collected at four <span class="hlt">hydrothermal</span> fields, both on- and off-axis of the back-arc spreading center of the Southern Mariana Trough. The microbial abundance and activity in the samples were determined by analyzing total organic content, enzymatic activity, and copy number of the 16S rRNA gene. To assess the diversity and composition of the microbial communities, 16S rRNA gene clone libraries including bacterial and archaeal phylotypes were constructed from the sulfide structures. Despite the differences in the geological settings among the sampling points, phylotypes related to the Epsilonproteobacteria and cultured hyperthermophilic archaea were abundant in the libraries from the samples of active <span class="hlt">vents</span>. In contrast, the relative abundance of these phylotypes was extremely low in the libraries from the samples of inactive <span class="hlt">vents</span>. These results suggest that the composition of microbial communities within sulfide structures dramatically changes depending on the degree of <span class="hlt">hydrothermal</span> activity, which was supported by statistical analyses. Comparative analyses suggest that the abundance, activity and diversity of microbial communities within sulfide structures of inactive <span class="hlt">vents</span> are likely to be comparable to or higher than those in active <span class="hlt">vent</span> structures, even though the microbial community composition is different between these two types of <span class="hlt">vents</span>. The microbial community compositions in the sulfide structures of inactive <span class="hlt">vents</span> were similar to those in seafloor basaltic rocks rather than those in marine sediments or the sulfide structures of active <span class="hlt">vents</span>, suggesting that the microbial community compositions on the seafloor may be constrained by the available energy sources. Our findings provide helpful information for understanding the biogeography, biodiversity and microbial ecosystems in marine environments. PMID:20228114</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2863450','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2863450"><span id="translatedtitle">Biogeography and Biodiversity in Sulfide Structures of Active and Inactive <span class="hlt">Vents</span> at Deep-Sea <span class="hlt">Hydrothermal</span> Fields of the Southern Mariana Trough? †</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kato, Shingo; Takano, Yoshinori; Kakegawa, Takeshi; Oba, Hironori; Inoue, Kazuhiko; Kobayashi, Chiyori; Utsumi, Motoo; Marumo, Katsumi; Kobayashi, Kensei; Ito, Yuki; Ishibashi, Jun-ichiro; Yamagishi, Akihiko</p> <p>2010-01-01</p> <p>The abundance, diversity, activity, and composition of microbial communities in sulfide structures both of active and inactive <span class="hlt">vents</span> were investigated by culture-independent methods. These sulfide structures were collected at four <span class="hlt">hydrothermal</span> fields, both on- and off-axis of the back-arc spreading center of the Southern Mariana Trough. The microbial abundance and activity in the samples were determined by analyzing total organic content, enzymatic activity, and copy number of the 16S rRNA gene. To assess the diversity and composition of the microbial communities, 16S rRNA gene clone libraries including bacterial and archaeal phylotypes were constructed from the sulfide structures. Despite the differences in the geological settings among the sampling points, phylotypes related to the Epsilonproteobacteria and cultured hyperthermophilic archaea were abundant in the libraries from the samples of active <span class="hlt">vents</span>. In contrast, the relative abundance of these phylotypes was extremely low in the libraries from the samples of inactive <span class="hlt">vents</span>. These results suggest that the composition of microbial communities within sulfide structures dramatically changes depending on the degree of <span class="hlt">hydrothermal</span> activity, which was supported by statistical analyses. Comparative analyses suggest that the abundance, activity and diversity of microbial communities within sulfide structures of inactive <span class="hlt">vents</span> are likely to be comparable to or higher than those in active <span class="hlt">vent</span> structures, even though the microbial community composition is different between these two types of <span class="hlt">vents</span>. The microbial community compositions in the sulfide structures of inactive <span class="hlt">vents</span> were similar to those in seafloor basaltic rocks rather than those in marine sediments or the sulfide structures of active <span class="hlt">vents</span>, suggesting that the microbial community compositions on the seafloor may be constrained by the available energy sources. Our findings provide helpful information for understanding the biogeography, biodiversity and microbial ecosystems in marine environments. PMID:20228114</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMOS53C1063T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMOS53C1063T"><span id="translatedtitle">Seismic structure at the Kairei <span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> field near the Rodriguez Triple Junction in the Indian Ocean</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Takata, H.; Sato, T.; Imai, Y.; Mori, T.; Noguchi, Y.; Kono, A.; Yamada, T.; Shinohara, M.</p> <p>2014-12-01</p> <p>Central Indian Ridge is located at the north of the Rodriguez Triple Junction and shows slow-intermediate spreading rate. The Kairei <span class="hlt">hydrothermal</span> Field (KHF) was discovered in the first segment of Central Indian Ridge near the Rodriguez Triple Junction. The <span class="hlt">vent</span> fluid which is extruding at the KHF has higher H2 content compared with other <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluid in the world. Although The KHF itself exists above a basaltic rock massif, gabbro and mafic rocks were discovered on the seafloor around the KHF. These deep-seated rocks may contribute to the high H2concentration of the Kairei <span class="hlt">vent</span> fluid .To understand how gabbro and mafic rocks are uplifted and exhumed on the seafloor, we conducted a seismic refraction/reflection survey using ocean bottom seismograms (OBSs). We conducted the seismic refraction/reflection survey from January 27 to March 19 in 2013 using S/V Yokosuka of Jamstec. In the experiment, we used 21 OBSs, an air gun (G.I.gun) and a single channel steamer cable. We obtained 5 survey lines NNW-SSE direction parallel to the ridge axis, 5 lines E-W direction and 5 lines NNE-SSW direction. In addition to these lines, we acquired other 5 lines passing through the point above the KHF or Yokoniwa Rise, which is the north of the KHF. In analysis of refraction data, firstly, we estimated 2D velocity model under survey lines, which are parallel to the ridge axis, using the progressive model development method developed by Sato and Kennett (2000). Then, we constructed a 3D initial model and run the 3D tomographic method developed by Zelt and Barton (1998). The 1D velocity profile of the KHF seems to be similar to that of mid ocean ridges such as Mid Atlantic Ridge, East Pacific Rise. Seismic velocities under the KHF and Yokoniwa Rise reach about 6km/s at depth of 1~2 km below seafloor, probably indicating uplift of deep-seated rocks. In this presentation we will show 3D seismic structure of this area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70016141','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70016141"><span id="translatedtitle">Microbial control of silver mineralization at a sea-floor <span class="hlt">hydrothermal</span> <span class="hlt">site</span> on the northern Gorda Ridge</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Zierenberg, R.A.; Schiffman, P.</p> <p>1990-01-01</p> <p>THE Sea Cliff <span class="hlt">hydrothermal</span> field, on the northern Gorda Ridge, contains mounds and chimneys of <span class="hlt">hydrothermally</span> precipitated sulphide and sulphate minerals typical of sea-floor <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span>1. In addition, large areas of the sea floor are covered by subhorizontal <span class="hlt">hydrothermal</span> crusts. Samples of the crust recovered by submersible are composed of intensely altered fragments of basalt and basaltic hyaloclastite cemented by amorphous silica and chalcedony with less abundant barite, and minor amounts of base-metal sulphide minerals2. Some surfaces of the crust were formerly colonized by bacterial mats, which are locally preserved by replacement and overgrowth of the bacterial filaments by metal sulphide minerals and amorphous silica. The bacterial filaments are selectively replaced by prousite (Ag3AsS3), pearceite3 (Ag14.7-XCu1.3+xAs2S11), chalcopyrite (CuFeS2) and rarely by galena (PbS). Our observations suggest that bacterially mediated processes selectively precipitate silver, arsenic and copper, and that biological processes may contribute to precious-metal enrichment in some sea-floor <span class="hlt">hydrothermal</span> base-metal sulphide deposits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMOS21A1482E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS21A1482E"><span id="translatedtitle">Barite chimneys from two <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> along the slow-spreading Arctic Ridge system: Initial isotope and mineralogical results</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eickmann, B.; van Zuilen, M. A.; Thorseth, I. H.; Pedersen, R.</p> <p>2010-12-01</p> <p>Two <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> along the slow-spreading Arctic Ridge systems, the Jan Mayen <span class="hlt">vent</span> fields (JMVFs) and the recently discovered Loki’s Castle <span class="hlt">hydrothermal</span> field (LCHF) contains numerous barite chimneys partially covered by microbial mats. The JMVFs are located at 71°N on the south-western Mohns Ridge, approximately 50 km north of the Jan Mayen fracture zone. The LCHF is located at 73.5°N on an axial volcanic ridge where the Mohns Ridge transitions into the Knipovich Ridge and consists of two <span class="hlt">venting</span> areas. Active <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> at both <span class="hlt">sites</span> is confirmed by elevated hydrogen sulphide concentrations and discharge of high-temperature fluids, reaching 270°C in the JMVFs and 317°C in the LCHF. Barite chimneys from the JMVFs are composed of barite, silica and abundant pyrite-dominated sulphide minerals that display a conspicuous concentric morphology. Raman spectroscopic analysis of the central regions of these concentric sulphide minerals points to the existence of mackinawite (FeS). Furthermore, the existence of greigite (Fe3S4) surrounding the mackinawite is suggested. This observation confirms the general conclusion of earlier experimental studies that these phases act as the metastable precursors of pyrite. In contrast, the barite chimneys of the LCHF consist mainly of pure barite with lesser amounts of sulphide minerals. The difference in the mineralogical composition between the two <span class="hlt">sites</span> is also expressed in its sulphur isotopic composition. ?34Ssulphate values of the barite chimneys from the JMVFs are lower than ?34S of seawater sulphate (?34S = +21‰) and ?34Ssulphide values point to a magmatic sulphur source (?34S = 0‰). This implies that the JMHFs barite chimneys have been formed by a mixture of seawater and <span class="hlt">hydrothermal</span> fluids, similar to the origin of black smokers. In contrast to the JMVFs, the ?34Ssulphate values from the LCHF barite chimneys are higher than ?34S values for seawater sulphate, but show remarkable differences between the surface of the chimneys and the interior. The highest ?34Ssulphate values have been found in the chimney interior, reaching ?34Ssulphate values up to +34.9‰. These high ?34Ssulphate values can be explained by various processes, including biogenic or thermogenic sulphate-reduction. The presence of twisted microstructures within the chimneys (reveiled by SEM) strongly suggests that biologic processes could have caused the observed sulphur isotope fractionation. Further mineralogical and isotope studies will provide more detailed insights on the formation of barite chimneys found in these <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> along the slow-spreading Arctic ridge system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://dspace.mit.edu/handle/1721.1/61888','EPRINT'); return false;" href="http://dspace.mit.edu/handle/1721.1/61888"><span id="translatedtitle">Identification of chemoautotrophic microorganisms from a diffuse flow <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> at EPR 9° north using ¹³C DNA stable isotope probing and catalyzed activated reporter deposition-fluorescence in situ hybridization</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Richberg, Kevin Patrick</p> <p>2010-01-01</p> <p>At deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> chemolithoautotrophic microbes mediate the transfer of geothermal chemical energy to higher trophic levels. To better understand these underlying processes and the organisms catalyzing them, ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3864839','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3864839"><span id="translatedtitle">High Connectivity of Animal Populations in Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Fields in the Central Indian Ridge Relevant to Its Geological Setting</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Beedessee, Girish; Watanabe, Hiromi; Ogura, Tomomi; Nemoto, Suguru; Yahagi, Takuya; Nakagawa, Satoshi; Nakamura, Kentaro; Takai, Ken; Koonjul, Meera; Marie, Daniel E. P.</p> <p>2013-01-01</p> <p>Dispersal ability plays a key role in the maintenance of species in spatially and temporally discrete niches of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments. On the basis of population genetic analyses in the eastern Pacific <span class="hlt">vent</span> fields, dispersal of animals in the mid-oceanic ridge systems generally appears to be constrained by geographical barriers such as trenches, transform faults, and microplates. Four <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields (the Kairei and Edmond fields near the Rodriguez Triple Junction, and the Dodo and Solitaire fields in the Central Indian Ridge) have been discovered in the mid-oceanic ridge system of the Indian Ocean. In the present study, we monitored the dispersal of four representative animals, Austinograea rodriguezensis, Rimicaris kairei, Alviniconcha and the scaly-foot gastropods, among these <span class="hlt">vent</span> fields by using indirect methods, i.e., phylogenetic and population genetic analyses. For all four investigated species, we estimated potentially high connectivity, i.e., no genetic difference among the populations present in <span class="hlt">vent</span> fields located several thousands of kilometers apart; however, the direction of migration appeared to differ among the species, probably because of different dispersal strategies. Comparison of the intermediate-spreading Central Indian Ridge with the fast-spreading East Pacific Rise and slow-spreading Mid-Atlantic Ridge revealed the presence of relatively high connectivity in the intermediate- and slow-spreading ridge systems. We propose that geological background, such as spreading rate which determines distance among <span class="hlt">vent</span> fields, is related to the larval dispersal and population establishment of <span class="hlt">vent</span>-endemic animal species, and may play an important role in controlling connectivity among populations within a biogeographical province. PMID:24358117</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24358117','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24358117"><span id="translatedtitle">High connectivity of animal populations in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields in the Central Indian Ridge relevant to its geological setting.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Beedessee, Girish; Watanabe, Hiromi; Ogura, Tomomi; Nemoto, Suguru; Yahagi, Takuya; Nakagawa, Satoshi; Nakamura, Kentaro; Takai, Ken; Koonjul, Meera; Marie, Daniel E P</p> <p>2013-01-01</p> <p>Dispersal ability plays a key role in the maintenance of species in spatially and temporally discrete niches of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments. On the basis of population genetic analyses in the eastern Pacific <span class="hlt">vent</span> fields, dispersal of animals in the mid-oceanic ridge systems generally appears to be constrained by geographical barriers such as trenches, transform faults, and microplates. Four <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields (the Kairei and Edmond fields near the Rodriguez Triple Junction, and the Dodo and Solitaire fields in the Central Indian Ridge) have been discovered in the mid-oceanic ridge system of the Indian Ocean. In the present study, we monitored the dispersal of four representative animals, Austinograea rodriguezensis, Rimicaris kairei, Alviniconcha and the scaly-foot gastropods, among these <span class="hlt">vent</span> fields by using indirect methods, i.e., phylogenetic and population genetic analyses. For all four investigated species, we estimated potentially high connectivity, i.e., no genetic difference among the populations present in <span class="hlt">vent</span> fields located several thousands of kilometers apart; however, the direction of migration appeared to differ among the species, probably because of different dispersal strategies. Comparison of the intermediate-spreading Central Indian Ridge with the fast-spreading East Pacific Rise and slow-spreading Mid-Atlantic Ridge revealed the presence of relatively high connectivity in the intermediate- and slow-spreading ridge systems. We propose that geological background, such as spreading rate which determines distance among <span class="hlt">vent</span> fields, is related to the larval dispersal and population establishment of <span class="hlt">vent</span>-endemic animal species, and may play an important role in controlling connectivity among populations within a biogeographical province. PMID:24358117</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4537116','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4537116"><span id="translatedtitle">Rhodopsin in the Dark Hot Sea: Molecular Analysis of Rhodopsin in a Snailfish, Careproctus rhodomelas, Living near the Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Sakata, Rie; Kabutomori, Ryo; Okano, Keiko; Mitsui, Hiromasa; Takemura, Akihiro; Miwa, Tetsuya; Yamamoto, Hiroyuki; Okano, Toshiyuki</p> <p>2015-01-01</p> <p>Visual systems in deep-sea fishes have been previously studied from a photobiological aspect; however, those of deep-sea fish inhabiting the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are far less understood due to sampling difficulties. In this study, we analyzed the visual pigment of a deep-sea snailfish, Careproctus rhodomelas, discovered and collected only near the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> of oceans around Japan. Proteins were solubilized from the C. rhodomelas eyeball and subjected to spectroscopic analysis, which revealed the presence of a pigment characterized by an absorption maximum (?max) at 480 nm. Immunoblot analysis of the ocular protein showed a rhodopsin-like immunoreactivity. We also isolated a retinal cDNA encoding the entire coding sequence of putative C. rhodomelas rhodopsin (CrRh). HEK293EBNA cells were transfected with the CrRh cDNA and the proteins extracted from the cells were subjected to spectroscopic analysis. The recombinant CrRh showed the absorption maximum at 480 nm in the presence of 11-cis retinal. Comparison of the results from the eyeball extract and the recombinant CrRh strongly suggests that CrRh has an A1-based 11-cis-retinal chromophore and works as a photoreceptor in the C. rhodomelas retina, and hence that C. rhodomelas responds to dim blue light much the same as other deep-sea fishes. Because <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> is a huge supply of viable food, C. rhodomelas likely do not need to participate diel vertical migration and may recognize the bioluminescence produced by aquatic animals living near the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. PMID:26275172</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26275172','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26275172"><span id="translatedtitle">Rhodopsin in the Dark Hot Sea: Molecular Analysis of Rhodopsin in a Snailfish, Careproctus rhodomelas, Living near the Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sakata, Rie; Kabutomori, Ryo; Okano, Keiko; Mitsui, Hiromasa; Takemura, Akihiro; Miwa, Tetsuya; Yamamoto, Hiroyuki; Okano, Toshiyuki</p> <p>2015-01-01</p> <p>Visual systems in deep-sea fishes have been previously studied from a photobiological aspect; however, those of deep-sea fish inhabiting the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are far less understood due to sampling difficulties. In this study, we analyzed the visual pigment of a deep-sea snailfish, Careproctus rhodomelas, discovered and collected only near the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> of oceans around Japan. Proteins were solubilized from the C. rhodomelas eyeball and subjected to spectroscopic analysis, which revealed the presence of a pigment characterized by an absorption maximum (?max) at 480 nm. Immunoblot analysis of the ocular protein showed a rhodopsin-like immunoreactivity. We also isolated a retinal cDNA encoding the entire coding sequence of putative C. rhodomelas rhodopsin (CrRh). HEK293EBNA cells were transfected with the CrRh cDNA and the proteins extracted from the cells were subjected to spectroscopic analysis. The recombinant CrRh showed the absorption maximum at 480 nm in the presence of 11-cis retinal. Comparison of the results from the eyeball extract and the recombinant CrRh strongly suggests that CrRh has an A1-based 11-cis-retinal chromophore and works as a photoreceptor in the C. rhodomelas retina, and hence that C. rhodomelas responds to dim blue light much the same as other deep-sea fishes. Because <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> is a huge supply of viable food, C. rhodomelas likely do not need to participate diel vertical migration and may recognize the bioluminescence produced by aquatic animals living near the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. PMID:26275172</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://arxiv.org/pdf/1008.2176.pdf','EPRINT'); return false;" href="http://arxiv.org/pdf/1008.2176.pdf"><span id="translatedtitle">Thermodynamics of chemical free energy generation in off-axis <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems and its consequences for compartmentalization and the emergence of life</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Simoncini, E; Gallori, E; .,</p> <p>2010-01-01</p> <p>In this paper we demonstrate how chemical free energy can be produced by a geological process. We provide a thermodynamic framework in which to assess how life emerged at the off-axis <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> system; the RNA - clays system has been investigated from the entropic point of view, showing that the stabilization of the system in a state further away from equilibrium state, by an inorganic heterogeneous compartmetalization phenomena, is able to produce chemical free energy useful for RNA self - replication.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850024761&hterms=Hydrothermal+vents&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2528Hydrothermal%2Bvents%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850024761&hterms=Hydrothermal+vents&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3D%2528Hydrothermal%2Bvents%2529"><span id="translatedtitle">Submarine <span class="hlt">hydrothermal</span> environments as <span class="hlt">sites</span> for the origin and evolution of life</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hoffman, S.; Baross, J.</p> <p>1985-01-01</p> <p>That life formed and evolved in <span class="hlt">hydrothermal</span> environments is proposed. This hypothesis is plausible in terms of the tectonic, paleontological, and degassing history of the Earth. Submarine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are the only contemporary geological environment which may truly be called primeval and which today continue to be a major source of gases and dissolved elements to the ocean. The microbial assemblages in present day <span class="hlt">hydrothermal</span> systems therefore could be living analogues of the earliest microbial communities to develop on Earth. The evidence for the hypothesis is reviewed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014E%26PSL.396..223Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014E%26PSL.396..223Z"><span id="translatedtitle">Rhenium-osmium abundance and isotopic compositions of massive sulfides from modern deep-sea <span class="hlt">hydrothermal</span> systems: Implications for <span class="hlt">vent</span> associated ore forming processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zeng, Zhigang; Chen, Shuai; Selby, David; Yin, Xuebo; Wang, Xiaoyuan</p> <p>2014-06-01</p> <p>Studies of rhenium (Re) and osmium (Os) concentrations and isotopic compositions in seafloor <span class="hlt">hydrothermal</span> sulfides are an important tool for understanding the evolution of <span class="hlt">hydrothermal</span> systems, allowing the determination of both metal sources and reconstructing the physicochemical conditions of their deposition. The Re-Os concentrations and isotopic compositions of 38 massive sulfide samples have been studied in different <span class="hlt">hydrothermal</span> fields from the East Pacific Rise (EPR), Mid-Atlantic Ridge (MAR), Central Indian Ridge (CIR), Southwest Indian Ridge (SWIR), and Back-Arc Basin (BAB). The majority of the sulfides possess 187Os/188Os that span a narrow range (1.004 to 1.209), which is most easily explained as a seawater-derived component. This may suggest that those initial 187Os/188Os isotope compositions of ancient seafloor <span class="hlt">hydrothermal</span> sulfide deposits which were formed by the mixing process between seawater and <span class="hlt">hydrothermal</span> fluid, are possible for analysing ancient seawater Os components. Only two of samples (MAR05-TVG1-10-2 and MAR05-TVG1-21 from the Logatchev <span class="hlt">hydrothermal</span> field (LHF), MAR) possess moderately less radiogenic 187Os/188Os (0.645 to 0.730), which may reflect the lesser extent of <span class="hlt">hydrothermal</span> fluid-seawater mixing during <span class="hlt">hydrothermal</span> ore-forming process. The Re and Os concentrations and 187Re/188Os ratios of pyrite and Fe-Cu sulfide mineral aggregates (avg Re 11.46 ppb; avg Os 17.76 ppt; avg 187Re/188Os 11,980.4; n=24) are usually higher than those of sphalerite or Zn-enriched sulfide mineral aggregate samples (avg Re 0.31 ppb; avg Os 7.09 ppt; avg 187Re/188Os 206.99; n=9), suggesting that Re and Os are more likely to be incorporated into Fe- and Fe-Cu sulfide mineral facies. A significant positive correlation is observed between Os/Re ratios and Pb concentrations in the sulfide samples from the Edmond <span class="hlt">hydrothermal</span> field (EHF), whereas Pb-enriched sulfide is characteristic of low-temperature paragenetic association, suggesting that Os enriched under low-temperature (<200 °C) condition. In addition, our Re-Os data are used to estimate that modern seafloor sulfide deposits contain roughly 0.6-44 t (avg 4 t, n=38) of Re, and 1 to 48 kg (avg 8 kg, n=38) of Os. The Os flux of global low-temperature <span class="hlt">hydrothermal</span> fluids to <span class="hlt">vents</span> is about 11 kg/yr, and the excess Os (i.e. Os not incorporated in sulfides) may be carried and become bound in metalliferous sediment, Fe-Mn crusts and nodules distal to the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DSRI..101....7S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DSRI..101....7S"><span id="translatedtitle">Relative abundances of methane- and sulfur-oxidizing symbionts in gills of the deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel Bathymodiolus azoricus under pressure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Szafranski, Kamil M.; Piquet, Bérénice; Shillito, Bruce; Lallier, François H.; Duperron, Sébastien</p> <p>2015-07-01</p> <p>The deep-sea mussel Bathymodiolus azoricus dominates <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fauna in the Azores region. The gills of this species house methane- and sulfur-oxidizing bacteria that fulfill most of the mussel's nutritional requirements. Previous studies suggested that the ratio between methane- and sulfur-oxidizers could vary in response to the availability of electron donors in their environment, and this flexibility is considered a key factor in explaining the ecological success of the species. However, previous studies were based on non-isobaric recovery of specimens, with experiments at atmospheric pressure which may have induced artifacts. This study investigates the effect of pressure-related stress during recovery and experimentation on the relative abundances of bacterial symbionts. Mussel specimens were recovered for the first time using the pressure-maintaining device PERISCOP. Specimens were subsequently transferred into pressurized vessels and exposed to various chemical conditions. Using optimized fluorescence in situ hybridization-based approaches, relative abundance of symbionts were measured. Our results show that the recovery method (isobaric versus non-isobaric) does not influence the abundances of bacterial symbionts. Significant differences occur among specimens sampled from two contrasting <span class="hlt">sites</span>. Exposure of mussels from the deeper <span class="hlt">site</span> to sulfide and bicarbonate, and to bicarbonate alone, both resulted in a rapid and significant increase in the relative abundance of sulfur-oxidizers. Results reported herein are congruent with those from previous reports investigating mussels originating from shallow <span class="hlt">sites</span> and kept at ambient pressure. Isobaric recovery and maintenance allowed us to perform in vivo experiments in specimens from a deeper <span class="hlt">site</span> that could not be maintained alive at ambient pressure, and will greatly improve the chances of identifying the molecular mechanisms underlying the dialogue between bathymodioline hosts and symbionts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26124448','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26124448"><span id="translatedtitle">Dual Cellular Supporters: Multi-Layer Glial Wrapping and the Penetrative Matrix Specialized in Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Endemic Scale-Worms.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shigeno, Shuichi; Tame, Akihiro; Uematsu, Katsuyuki; Miura, Tomoyuki; Tsuchida, Shinji; Fujikura, Katsunori</p> <p>2015-06-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> organisms undergo extreme environments that may require unique innovations. The present study reports a distinct case of cellular supportive systems in the nervous systems of a scale-worm, Branchinotogluma japonica, endemic to deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. We found two organizations in the tissues of these animals. First, multi-layers of glia ensheath the ventral cell bodies of the brain and ventral nerve cord, in a manner similar to that of myelin or lamellar ensheathments. Second, matrices of numerous penetrative fibers, or tonofilaments, composed of bundles of ca. 20-nm fibers, are directly connected with the basal parts of epidermal cuticles and run into the diffuse intercellular spaces of the brain neuropils and peripheral nerves. Both types of tissue might be mechanical supportive structures for the neuronal cell bodies. In addition, as a glial function, the multi-layer membranes and the epithelial support cells may be required for physicochemical homeostatic regulation to filter toxic heavy metals and for inhibiting breakdown of glial membrane integrity under strong oxidative stress imposed by hypoxia in the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environment. Similar functions are known in the well-studied cases of the blood-brain barrier in mammalian brains, including in human stroke. PMID:26124448</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DSRI..100...13S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DSRI..100...13S"><span id="translatedtitle">Sources of organic carbon for Rimicaris hybisae: Tracing individual fatty acids at two <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields in the Mid-Cayman rise</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Streit, Kathrin; Bennett, Sarah A.; Van Dover, Cindy L.; Coleman, Max</p> <p>2015-06-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> harbor ecosystems mostly decoupled from organic carbon synthesized with the energy of sunlight (photosynthetic carbon source) but fueled instead by oxidation of reduced compounds to generate a chemosynthetic carbon source. Our study aimed to disentangle photosynthetic and chemosynthetic organic carbon sources for the shrimp species Rimicaris hybisae, a primary consumer presumed to obtain its organic carbon mainly from ectosymbiotic chemoautotrophic bacteria living on its gill cover membrane. To provide ectosymbionts with ideal conditions for chemosynthesis, these shrimp live in dense clusters around <span class="hlt">vent</span> chimneys; they are, however, also found sparsely distributed adjacent to diffuse <span class="hlt">vent</span> flows, where they might depend on alternative food sources. Densely and sparsely distributed shrimp were sampled and dissected into abdominal tissue and gill cover membrane, covered with ectosymbiotic bacteria, at two <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields in the Mid-Cayman rise that differ in <span class="hlt">vent</span> chemistry. Fatty acids (FA) were extracted from shrimp tissues and their carbon isotopic compositions assessed. The FA data indicate that adult R. hybisae predominantly rely on bacteria for their organic carbon needs. Their FA composition is dominated by common bacterial FA of the n7 family (~41%). Bacterial FA of the n4 FA family are also abundant and found to constitute good biomarkers for gill ectosymbionts. Sparsely distributed shrimp contain fractions of n4 FA in gill cover membranes ~4% lower than densely packed ones (~18%) and much higher fractions of photosynthetic FA in abdominal tissues, ~4% more (compared with 1.6%), suggesting replacement of ectosymbionts along with exoskeletons (molt), while they take up alternative diets of partly photosynthetic organic carbon. Abdominal tissues also contain photosynthetic FA from a second source taken up presumably during an early dispersal phase and still present to c. 3% in adult shrimp. The contribution of photosynthetic carbon to the FA pool of adult R. hybisae is, however, overall small (max. 8%). Significant differences in carbon isotopic values of chemosynthetically derived FA between <span class="hlt">vent</span> fields suggest that different dominant C fixation pathways are being used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2685390','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2685390"><span id="translatedtitle">DIRS1-like retrotransposons are widely distributed among Decapoda and are particularly present in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> organisms</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Piednoël, Mathieu; Bonnivard, Eric</p> <p>2009-01-01</p> <p>Background Transposable elements are major constituents of eukaryote genomes and have a great impact on genome structure and stability. Considering their mutational abilities, TEs can contribute to the genetic diversity and evolution of organisms. Knowledge of their distribution among several genomes is an essential condition to study their dynamics and to better understand their role in species evolution. DIRS1-like retrotransposons are a particular group of retrotransposons according to their mode of transposition that implies a tyrosine recombinase. To date, they have been described in a restricted number of species in comparison with the LTR retrotransposons. In this paper, we determine the distribution of DIRS1-like elements among 25 decapod species, 10 of them living in <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> that correspond to particularly unstable environments. Results Using PCR approaches, we have identified 15 new DIRS1-like families in 15 diverse decapod species (shrimps, lobsters, crabs and galatheid crabs). <span class="hlt">Hydrothermal</span> organisms show a particularly great diversity of DIRS1-like elements with 5 families characterized among Alvinocarididae shrimps and 3 in the galatheid crab Munidopsis recta. Phylogenic analyses show that these elements are divergent toward the DIRS1-like families previously described in other crustaceans and arthropods and form a new clade called AlDIRS1. At larger scale, the distribution of DIRS1-like retrotransposons appears more or less patchy depending on the taxa considered. Indeed, a scattered distribution can be observed in the infraorder Brachyura whereas all the species tested in infraorders Caridea and Astacidea harbor some DIRS1-like elements. Conclusion Our results lead to nearly double both the number of DIRS1-like elements described to date, and the number of species known to harbor these ones. In this study, we provide the first degenerate primers designed to look specifically for DIRS1-like retrotransposons. They allowed for revealing for the first time a widespread distribution of these elements among a large phylum, here the order Decapoda. They also suggest some peculiar features of these retrotransposons in <span class="hlt">hydrothermal</span> organisms where a great diversity of elements is already observed. Finally, this paper constitutes the first essential step which allows for considering further studies based on the dynamics of the DIRS1-like retrotransposons among several genomes. PMID:19400949</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=205561','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=205561"><span id="translatedtitle">Characterization of the gene encoding the autotrophic ATP sulfurylase from the bacterial endosymbiont of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworm Riftia pachyptila.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Laue, B E; Nelson, D C</p> <p>1994-01-01</p> <p>ATP sulfurylase is a key enzyme in the energy-generating sulfur oxidation pathways of many chemoautotrophic bacteria. The utilization of reduced sulfur compounds to fuel CO2 fixation by the still-uncultured bacterial endosymbionts provides the basis of nutrition in invertebrates, such as the tubeworm Riftia pachyptila, found at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. The symbiont-containing trophosome tissue contains high levels of ATP sulfurylase activity, facilitating the recent purification of the enzyme. The gene encoding the ATP sulfurylase from the Riftia symbiont (sopT) has now been cloned and sequenced by using the partial amino acid sequence of the purified protein. Characterization of the sopT gene has unequivocally shown its bacterial origin. This is the first ATP sulfurylase gene to be cloned and sequenced from a sulfur-oxidizing bacterium. The deduced amino acid sequence was compared to those of ATP sulfurylases reported from organisms which assimilate sulfate, resulting in the discovery that there is substantial homology with the Saccharomyces cerevisiae MET3 gene product but none with the products of the cysDN genes from Escherichia coli nor with the nodP and nodQ genes from Rhizobium meliloti. This and emerging evidence from other sources suggests that E. coli may be atypical, even among prokaryotic sulfate assimilators, in the enzyme it employs for adenosine 5'-phosphosulfate formation. The sopT gene probe also was shown to specifically identify chemoautotrophic bacteria which utilize ATP sulfurylase to oxidize sulfur compounds. Images PMID:8206850</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/10976028','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/10976028"><span id="translatedtitle">Nitrogen metabolites and related enzymatic activities in the body fluids and tissues of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworm Riftia pachyptila.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>De Cian, M; Regnault, M; Lallier, F H</p> <p>2000-10-01</p> <p>The distribution of nitrogen metabolism end-products and the associated enzyme activities, free amino acids and purine base catabolites were investigated in all the body compartments (circulating fluids and tissues) of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworm Riftia pachyptila to acquire a general overview of nitrogen metabolism in this symbiotic organism. There were striking differences between the symbiont-containing trophosome tissue and other host tissues. High concentrations of ammonia, creatinine and, in particular, urate were found in all tissues, but they were present at consistently higher concentrations in the trophosome, which also contained large amounts of urea. Uric acid crystals were present at the periphery of trophosome lobules. The urea cycle appears to be fully functional in this tissue, which also uses creatine phosphate for phosphagen storage, while arginine phosphate or a combination of both phosphagens occurs in other tissues. The amino acid patterns are dominated by sulphated compounds in all tissues except the trophosome, which has high levels of aspartate and glutamate. Although no definitive conclusions could be drawn regarding the nitrogen regime of Riftia pachyptila, this in vitro study gives several indications for future research in this area. PMID:10976028</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/10081955','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/10081955"><span id="translatedtitle">Hemoglobins from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> scaleworms of the genus Branchipolynoe: a new type of quaternary structure.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hourdez, S; Lallier, F H; Green, B N; Toulmond, A</p> <p>1999-03-01</p> <p>Branchipolynoe symmytilida and B. seepensis are two scaleworms (Polychaeta; Polynoidae) living commensally in the mantle cavity of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> and cold-seep mussels. In contrast with littoral members of this family, the two species exhibit a large amount of extracellular hemoglobin (Hb) in their coelomic fluid. Gel filtration revealed the existence of four different Hbs: one minor, high molecular mass (3x10(6) Da) Hb, V1-Hb, reminiscent of a vascular hexagonal bilayer annelid Hb; two major coelomic Hbs, C1-Hb, and C2-Hb, with unusual masses for extracellular annelid Hbs of 153 and 124 kDa respectively; and a minor probably coelomic Hb of 23 kDa (C3-Hb). Using electrospray ionization mass spectrometry, SDS-PAGE after subtilisin treatment, and tandem mass spectrometry, we showed that C1-Hb is a trimer of a 57,996 Da chain and C2-Hb is a dimer of a 57,648 Da chain, each chain being a four-domain/four-heme polypeptide. This multimeric, multidomain arrangement is unique among annelid Hbs and appears different from that of other known multidomain Hbs. PMID:10081955</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12881565','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12881565"><span id="translatedtitle">30,000 years of <span class="hlt">hydrothermal</span> activity at the lost city <span class="hlt">vent</span> field.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Früh-Green, Gretchen L; Kelley, Deborah S; Bernasconi, Stefano M; Karson, Jeffrey A; Ludwig, Kristin A; Butterfield, David A; Boschi, Chiara; Proskurowski, Giora</p> <p>2003-07-25</p> <p>Strontium, carbon, and oxygen isotope data and radiocarbon ages document at least 30,000 years of <span class="hlt">hydrothermal</span> activity driven by serpentinization reactions at Lost City. Serpentinization beneath this off-axis field is estimated to occur at a minimum rate of 1.2 x 10(-4) cubic kilometers per year. The access of seawater to relatively cool, fresh peridotite, coupled with faulting, volumetric expansion, and mass wasting processes, are crucial to sustain such systems. The amount of heat produced by serpentinization of peridotite massifs, typical of slow and ultraslow spreading environments, has the potential to drive Lost City-type systems for hundreds of thousands, possibly millions, of years. PMID:12881565</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005DSRI...52.1085M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005DSRI...52.1085M"><span id="translatedtitle">Flow-type apparatus for studying thermotolerance of hyperthermophiles under conditions simulating <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> circulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mitsuzawa, Shigenobu; Deguchi, Shigeru; Takai, Ken; Tsujii, Kaoru; Horikoshi, Koki</p> <p>2005-06-01</p> <p>A flow-type apparatus has been developed to study thermotolerance of microorganisms under conditions simulating submarine <span class="hlt">hydrothermal</span> circulation. The apparatus is designed so that microorganisms can be exposed to high temperature for periods of only a few seconds duration, and can be operated at temperatures up to 400 °C and hydrostatic pressures up to 30 MPa, even under strict anaerobic conditions. The performance of the apparatus was tested by studying the thermotolerance of a mesophilic bacterium, Escherichia coli strain W3110, after heat treatment at temperatures between 59.0 and 64.5 °C for 1.5 s. The results compared favorably with the literature data obtained by a conventional batch method at lower temperatures and longer heating durations. Thermotolerance of a hyperthermophilic archaeon, Pyrococcus horikoshii strain OT3, was successfully determined by the apparatus at temperatures up to 119 °C and pressures up to 25 MPa under anaerobic conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/14871207','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/14871207"><span id="translatedtitle">Early steps in microbial colonization processes at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alain, Karine; Zbinden, Magali; Le Bris, Nadine; Lesongeur, Françoise; Quérellou, Joël; Gaill, Françoise; Cambon-Bonavita, Marie-Anne</p> <p>2004-03-01</p> <p>A pluri-disciplinary in situ colonization experiment was performed to study early stages of colonization in deep-sea <span class="hlt">vent</span> Alvinella spp. worm habitats. Four colonization devices were deployed onto Alvinella spp. colonies of different chimneys of the East-Pacific Rise (EPR 13 degrees N), for two different periods: a short (less than a week) and a longer one (3 weeks). Video imagery and monitoring of the thermal and physico-chemical conditions were performed during the colonization experiments. Numerous microorganisms bearing specialized adhesion-appendages and/or high amounts of polymeric extracellular matrix were observed on devices, which may efficiently contribute to the colonization of new surfaces. The microbial cohorts preceding and accompanying Alvinella spp. settlement were identified. In all cases, Archaea could not be detected and the microbial mats were essentially composed of e-Proteobacteria. Within this group, one phylotype (AlviH2) was found to dominate the libraries of three colonization devices. Dominance of e-Proteobacteria in the libraries may reflect the wide physiological variety encountered within this group or an adaptability of these microorganisms towards their changing environment. Bacteria affiliated to the Cytophaga-Flavobacterium-Bacteroides group or to the e-Proteobacteria, that grow either chemo-organoheterotrophically by fermentation or chemolithoautotrophically with H2 as an electron donor and S degrees /S2O32- or NO3- as a terminal electron acceptor, were isolated from one of the microbial mat formed in 20 days. PMID:14871207</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4335981','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4335981"><span id="translatedtitle">Linking regional variation of epibiotic bacterial diversity and trophic ecology in a new species of Kiwaidae (Decapoda, Anomura) from East Scotia Ridge (Antarctica) <span class="hlt">hydrothermal</span> <span class="hlt">vents</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zwirglmaier, Katrin; Reid, William D K; Heywood, Jane; Sweeting, Christopher J; Wigham, Benjamin D; Polunin, Nicholas V C; Hawkes, Jeff A; Connelly, Douglas P; Pearce, David; Linse, Katrin</p> <p>2015-01-01</p> <p>We analyzed the diversity of bacterial epibionts and trophic ecology of a new species of Kiwa yeti crab discovered at two <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields (E2 and E9) on the East Scotia Ridge (ESR) in the Southern Ocean using a combination of 454 pyrosequencing, Sanger sequencing, and stable isotope analysis. The Kiwa epibiont communities were dominated by Epsilon- and Gammaproteobacteria. About 454 sequencing of the epibionts on 15 individual Kiwa specimen revealed large regional differences between the two <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields: at E2, the bacterial community on the Kiwa ventral setae was dominated (up to 75%) by Gammaproteobacteria, whereas at E9 Epsilonproteobacteria dominated (up to 98%). Carbon stable isotope analysis of both Kiwa and the bacterial epibionts also showed distinct differences between E2 and E9 in mean and variability. Both stable isotope and sequence data suggest a dominance of different carbon fixation pathways of the epibiont communities at the two <span class="hlt">vent</span> fields. At E2, epibionts were putatively fixing carbon via the Calvin-Benson-Bassham and reverse tricarboxylic acid cycle, while at E9 the reverse tricarboxylic acid cycle dominated. Co-varying epibiont diversity and isotope values at E2 and E9 also present further support for the hypothesis that epibionts serve as a food source for Kiwa. PMID:25515351</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DSRI..100...48N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DSRI..100...48N"><span id="translatedtitle">Insights into life-history traits of Munidopsis spp. (Anomura: Munidopsidae) from <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields in the Okinawa Trough, in comparison with the existing data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakamura, Masako; Chen, Chong; Mitarai, Satoshi</p> <p>2015-06-01</p> <p>Squat lobsters in the genus Munidopsis are commonly found at, and near, <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. However, the reproductive traits of most Munidopsis spp. are unknown. This study examined the reproductive features of two Munidopsis species sampled from <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields in the southern Okinawa Trough in February 2014. Three ovigerous females were collected: two Munidopsis ryukyuensis at Irabu Knoll (1661-1675 m depth) and one M. longispinosa at Hatoma Knoll (1482 m depth). Carapace sizes and egg volumes were measured and compared with those of other Munidopsis species. The ovigerous M. ryukyuensis specimens had postorbital carapace lengths of 10.3 and 11.8 mm, without the rostrum, and carapace widths of 8.6 and 9.7 mm. Mean egg volumes of M. ryukyuensis and M. longispinosa were ~4 mm3. These results are consistent with early sexual maturity in M. ryukyuensis and lecithotrophic development in both species, as described in other species of the genus. These life-history traits may enable these <span class="hlt">vent</span> species to maximize their reproductive and dispersive potential.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25515351','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25515351"><span id="translatedtitle">Linking regional variation of epibiotic bacterial diversity and trophic ecology in a new species of Kiwaidae (Decapoda, Anomura) from East Scotia Ridge (Antarctica) <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zwirglmaier, Katrin; Reid, William D K; Heywood, Jane; Sweeting, Christopher J; Wigham, Benjamin D; Polunin, Nicholas V C; Hawkes, Jeff A; Connelly, Douglas P; Pearce, David; Linse, Katrin</p> <p>2015-02-01</p> <p>We analyzed the diversity of bacterial epibionts and trophic ecology of a new species of Kiwa yeti crab discovered at two <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields (E2 and E9) on the East Scotia Ridge (ESR) in the Southern Ocean using a combination of 454 pyrosequencing, Sanger sequencing, and stable isotope analysis. The Kiwa epibiont communities were dominated by Epsilon- and Gammaproteobacteria. About 454 sequencing of the epibionts on 15 individual Kiwa specimen revealed large regional differences between the two <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields: at E2, the bacterial community on the Kiwa ventral setae was dominated (up to 75%) by Gammaproteobacteria, whereas at E9 Epsilonproteobacteria dominated (up to 98%). Carbon stable isotope analysis of both Kiwa and the bacterial epibionts also showed distinct differences between E2 and E9 in mean and variability. Both stable isotope and sequence data suggest a dominance of different carbon fixation pathways of the epibiont communities at the two <span class="hlt">vent</span> fields. At E2, epibionts were putatively fixing carbon via the Calvin-Benson-Bassham and reverse tricarboxylic acid cycle, while at E9 the reverse tricarboxylic acid cycle dominated. Co-varying epibiont diversity and isotope values at E2 and E9 also present further support for the hypothesis that epibionts serve as a food source for Kiwa. PMID:25515351</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18097639','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18097639"><span id="translatedtitle">Ultrastructural and molecular evidence for potentially symbiotic bacteria within the byssal plaques of the deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel Bathymodiolus azoricus.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kádár, Enikõ; Bettencourt, Raul</p> <p>2008-08-01</p> <p>This study reports on the presence of a putatively symbiotic bacterial flora within the byssus plaque of the deep sea <span class="hlt">hydrothermal</span> mussel Bathymodiolus azoricus, contributing to metal sequestration/deposition and testing positive to methane oxidizing symbiont-specific fluorescent probes. Combining an array of approaches including histology, electron microscopy, X-ray microanalysis, analytical chemistry, and microbiology we provide evidence for the frequently assumed, but rarely shown influence of prokaryotes on the biogeochemical cycling of metals as well as inorganic C sources (i.e., methane) at deep sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Our results indicate that in spite of its antibacterial protective sheath, the byssus plaque gives access to a whole range of prokaryotic organisms which may be responsible for the extremely high concentration of metallic elements (Fe, Cu, Zn, Mn, Co, Mo, Cd, Pb and Hg) measured in this attachment organ. The very high levels of metals in byssus, together with its frequent renewal rate due to the dynamic nature of the habitat, suggest that intra-byssal bacteria may have a major influence on biomineralisation/deposition of metals. The presence of a methanotroph morphotype within the byssus plaque was confirmed by FISH and TEM. The implications of the biogeochemical cycling of metals and methane at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are discussed. PMID:18097639</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4250120','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4250120"><span id="translatedtitle">Distal transport of dissolved <span class="hlt">hydrothermal</span> iron in the deep South Pacific Ocean</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fitzsimmons, Jessica N.; Boyle, Edward A.; Jenkins, William J.</p> <p>2014-01-01</p> <p>Until recently, <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> were not considered to be an important source to the marine dissolved Fe (dFe) inventory because <span class="hlt">hydrothermal</span> Fe was believed to precipitate quantitatively near the <span class="hlt">vent</span> <span class="hlt">site</span>. Based on recent abyssal dFe enrichments near <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, however, the leaky <span class="hlt">vent</span> hypothesis [Toner BM, et al. (2012) Oceanography 25(1):209–212] argues that some <span class="hlt">hydrothermal</span> Fe persists in the dissolved phase and contributes a significant flux of dFe to the global ocean. We show here the first, to our knowledge, dFe (<0.4 µm) measurements from the abyssal southeast and southwest Pacific Ocean, where dFe of 1.0–1.5 nmol/kg near 2,000 m depth (0.4–0.9 nmol/kg above typical deep-sea dFe concentrations) was determined to be <span class="hlt">hydrothermally</span> derived based on its correlation with primordial 3He and dissolved Mn (dFe:3He of 0.9–2.7 × 106). Given the known <span class="hlt">sites</span> of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> in these regions, this dFe must have been transported thousands of kilometers away from its <span class="hlt">vent</span> <span class="hlt">site</span> to reach our sampling stations. Additionally, changes in the size partitioning of the <span class="hlt">hydrothermal</span> dFe between soluble (<0.02 µm) and colloidal (0.02–0.4 µm) phases with increasing distance from the <span class="hlt">vents</span> indicate that dFe transformations continue to occur far from the <span class="hlt">vent</span> source. This study confirms that although the southern East Pacific Rise only leaks 0.02–1% of total Fe <span class="hlt">vented</span> into the abyssal Pacific, this dFe persists thousands of kilometers away from the <span class="hlt">vent</span> source with sufficient magnitude that <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> can have far-field effects on global dFe distributions and inventories (?3% of global aerosol dFe input). PMID:25349389</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25349389','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25349389"><span id="translatedtitle">Distal transport of dissolved <span class="hlt">hydrothermal</span> iron in the deep South Pacific Ocean.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fitzsimmons, Jessica N; Boyle, Edward A; Jenkins, William J</p> <p>2014-11-25</p> <p>Until recently, <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> were not considered to be an important source to the marine dissolved Fe (dFe) inventory because <span class="hlt">hydrothermal</span> Fe was believed to precipitate quantitatively near the <span class="hlt">vent</span> <span class="hlt">site</span>. Based on recent abyssal dFe enrichments near <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, however, the leaky <span class="hlt">vent</span> hypothesis [Toner BM, et al. (2012) Oceanography 25(1):209-212] argues that some <span class="hlt">hydrothermal</span> Fe persists in the dissolved phase and contributes a significant flux of dFe to the global ocean. We show here the first, to our knowledge, dFe (<0.4 µm) measurements from the abyssal southeast and southwest Pacific Ocean, where dFe of 1.0-1.5 nmol/kg near 2,000 m depth (0.4-0.9 nmol/kg above typical deep-sea dFe concentrations) was determined to be <span class="hlt">hydrothermally</span> derived based on its correlation with primordial (3)He and dissolved Mn (dFe:(3)He of 0.9-2.7 × 10(6)). Given the known <span class="hlt">sites</span> of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> in these regions, this dFe must have been transported thousands of kilometers away from its <span class="hlt">vent</span> <span class="hlt">site</span> to reach our sampling stations. Additionally, changes in the size partitioning of the <span class="hlt">hydrothermal</span> dFe between soluble (<0.02 µm) and colloidal (0.02-0.4 µm) phases with increasing distance from the <span class="hlt">vents</span> indicate that dFe transformations continue to occur far from the <span class="hlt">vent</span> source. This study confirms that although the southern East Pacific Rise only leaks 0.02-1% of total Fe <span class="hlt">vented</span> into the abyssal Pacific, this dFe persists thousands of kilometers away from the <span class="hlt">vent</span> source with sufficient magnitude that <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> can have far-field effects on global dFe distributions and inventories (?3% of global aerosol dFe input). PMID:25349389</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3526180','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3526180"><span id="translatedtitle">Inorganic carbon fixation by chemosynthetic ectosymbionts and nutritional transfers to the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> host-shrimp Rimicaris exoculata</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ponsard, Julie; Cambon-Bonavita, Marie-Anne; Zbinden, Magali; Lepoint, Gilles; Joassin, André; Corbari, Laure; Shillito, Bruce; Durand, Lucile; Cueff-Gauchard, Valérie; Compère, Philippe</p> <p>2013-01-01</p> <p>The shrimp Rimicaris exoculata dominates several <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystems of the Mid-Atlantic Ridge and is thought to be a primary consumer harbouring a chemoautotrophic bacterial community in its gill chamber. The aim of the present study was to test current hypotheses concerning the epibiont's chemoautotrophy, and the mutualistic character of this association. In-vivo experiments were carried out in a pressurised aquarium with isotope-labelled inorganic carbon (NaH13CO3 and NaH14CO3) in the presence of two different electron donors (Na2S2O3 and Fe2+) and with radiolabelled organic compounds (14C-acetate and 3H-lysine) chosen as potential bacterial substrates and/or metabolic by-products in experiments mimicking transfer of small biomolecules from epibionts to host. The bacterial epibionts were found to assimilate inorganic carbon by chemoautotrophy, but many of them (thick filaments of epsilonproteobacteria) appeared versatile and able to switch between electron donors, including organic compounds (heterotrophic acetate and lysine uptake). At least some of them (thin filamentous gammaproteobacteria) also seem capable of internal energy storage that could supply chemosynthetic metabolism for hours under conditions of electron donor deprivation. As direct nutritional transfer from bacteria to host was detected, the association appears as true mutualism. Import of soluble bacterial products occurs by permeation across the gill chamber integument, rather than via the digestive tract. This first demonstration of such capabilities in a decapod crustacean supports the previously discarded hypothesis of transtegumental absorption of dissolved organic matter or carbon as a common nutritional pathway. PMID:22914596</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3372519','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3372519"><span id="translatedtitle">Expression and Putative Function of Innate Immunity Genes under in situ Conditions in the Symbiotic <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Tubeworm Ridgeia piscesae</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Nyholm, Spencer V.; Song, Pengfei; Dang, Jeanne; Bunce, Corey; Girguis, Peter R.</p> <p>2012-01-01</p> <p>The relationships between <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworms and sulfide-oxidizing bacteria have served as model associations for understanding chemoautotrophy and endosymbiosis. Numerous studies have focused on the physiological and biochemical adaptations that enable these symbioses to sustain some of the highest recorded carbon fixation rates ever measured. However, far fewer studies have explored the molecular mechanisms underlying the regulation of host and symbiont interactions, specifically those mediated by the innate immune system of the host. To that end, we conducted a series of studies where we maintained the tubeworm, Ridgeia piscesae, in high-pressure aquaria and examined global and quantitative changes in gene expression via high-throughput transcriptomics and quantitative real-time PCR (qPCR). We analyzed over 32,000 full-length expressed sequence tags as well as 26 Mb of transcript sequences from the trophosome (the organ that houses the endosymbiotic bacteria) and the plume (the gas exchange organ in contact with the free-living microbial community). R. piscesae maintained under conditions that promote chemoautotrophy expressed a number of putative cell signaling and innate immunity genes, including pattern recognition receptors (PRRs), often associated with recognizing microbe-associated molecular patterns (MAMPs). Eighteen genes involved with innate immunity, cell signaling, cell stress and metabolite exchange were further analyzed using qPCR. PRRs, including five peptidoglycan recognition proteins and a Toll-like receptor, were expressed significantly higher in the trophosome compared to the plume. Although PRRs are often associated with mediating host responses to infection by pathogens, the differences in expression between the plume and trophosome also implicate similar mechanisms of microbial recognition in interactions between the host and symbiont. We posit that regulation of this association involves a molecular “dialogue” between the partners that includes interactions between the host’s innate immune system and the symbiont. PMID:22701617</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25604337','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25604337"><span id="translatedtitle">Cetia pacifica gen. nov., sp. nov., a chemolithoautotrophic, thermophilic, nitrate-ammonifying bacterium from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Grosche, Ashley; Sekaran, Hema; Pérez-Rodríguez, Ileana; Starovoytov, Valentin; Vetriani, Costantino</p> <p>2015-04-01</p> <p>A thermophilic, anaerobic, chemolithoautotrophic bacterium, strain TB-6(T), was isolated from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> located on the East Pacific Rise at 9° N. The cells were Gram-staining-negative and rod-shaped with one or more polar flagella. Cell size was approximately 1-1.5 µm in length and 0.5 µm in width. Strain TB-6(T) grew between 45 and 70 °C (optimum 55-60 °C), 0 and 35 g NaCl l(-1) (optimum 20-30 g l(-1)) and pH 4.5 and 7.5 (optimum pH 5.5-6.0). Generation time under optimal conditions was 2 h. Growth of strain TB-6(T) occurred with H2 as the energy source, CO2 as the carbon source and nitrate or sulfur as electron acceptors, with formation of ammonium or hydrogen sulfide, respectively. Acetate, (+)-d-glucose, Casamino acids, sucrose and yeast extract were not used as carbon and energy sources. Inhibition of growth occurred in the presence of lactate, peptone and tryptone under a H2/CO2 (80?:?20; 200 kPa) gas phase. Thiosulfate, sulfite, arsenate, selenate and oxygen were not used as electron acceptors. The G+C content of the genomic DNA was 36.8 mol%. Phylogenetic analysis of the 16S rRNA gene of strain TB-6(T) showed that this organism branched separately from the three most closely related genera, Caminibacter , Nautilia and Lebetimonas , within the family Nautiliaceae . Strain TB-6(T) contained several unique fatty acids in comparison with other members of the family Nautiliaceae . Based on experimental evidence, it is proposed that the organism represents a novel species and genus within the family Nautiliaceae , Cetia pacifica, gen. nov., sp. nov. The type strain is TB-6(T) (?=?DSM 27783(T)?=?JCM 19563(T)). PMID:25604337</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18842837','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18842837"><span id="translatedtitle">Exilispira thermophila gen. nov., sp. nov., an anaerobic, thermophilic spirochaete isolated from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimney.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Imachi, Hiroyuki; Sakai, Sanae; Hirayama, Hisako; Nakagawa, Satoshi; Nunoura, Takuro; Takai, Ken; Horikoshi, Koki</p> <p>2008-10-01</p> <p>A novel thermophilic, anaerobic bacterium, strain RASEN(T), was isolated from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimney sample collected in the Iheya North field, Okinawa Trough, Japan, at a water depth of 982 m. The cells were motile, Gram-negative and helical with hooked ends, 0.23-0.28x15-27 microm in size with an approximate wavelength of 1.1-1.5 microm. Growth of the strain was observed at 37-60 degrees C (optimum 50 degrees C), in 2.5-3.5 % (w/v) NaCl (optimum 2.5-3 % NaCl) and at pH 6.0-7.5 (optimum pH 7.0). The strain grew on yeast extract only of the substrates examined in this study. The G+C content of the genomic DNA was 27.1 mol%. Major fatty acids for the strain were C(16 : 0), C(18 : 1)(Delta9) trans, C(18 : 0) and C(18 : 1)(Delta9) cis. Based on comparative 16S rRNA gene sequence analysis, strain RASEN(T) formed a deeply branching lineage within the phylum Spirochaetes and had only low levels of sequence similarity with other species of the phylum (range of similarity 72.1-80.6 %). Hence, we propose the name Exilispira thermophila gen. nov., sp. nov. The type strain of Exilispira thermophila is strain RASEN(T) (=JCM 14728(T) =NBRC 103205(T) =KCTC 5595(T)). PMID:18842837</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26404429','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26404429"><span id="translatedtitle">Citreicella manganoxidans sp. nov., a novel manganese oxidizing bacterium isolated from a shallow water <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> in Espalamaca (Azores).</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rajasabapathy, Raju; Mohandass, Chellandi; Dastager, Syed Gulam; Liu, Qing; Li, Wen-Jun; Colaço, Ana</p> <p>2015-12-01</p> <p>A Gram-stain negative, non-motile, non-spore forming, aerobic and rod or narrow lemon-shaped bacterial strain, VSW210(T), was isolated from surface seawater in a shallow water <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> region in Espalamaca (Azores). Strain VSW210(T) was found to grow optimally at 30 °C, at pH 7 and in the presence of 2-6 % (w/v) NaCl. A neighbour-joining phylogenetic tree based on 16S rRNA gene sequences revealed that strain VSW210(T) clusters with the type strain Citreicella marina CK-I3-6(T) (sequence similarity value of 99.6 %), but DNA-DNA hybridization showed DNA-DNA relatedness between the strain VSW210(T) and C. marina CK-I3-6(T) to be 55.8 ± 3.2 %. The DNA G+C content of strain VSW210(T) was determined to be 67.4 mol%. The cellular fatty acid profiles of strain VSW210(T) was found to contain C18:1 ?7c (80.1 %) and C16:0 (9.2 %). The major polar lipids in strain VSW210(T) were identified as phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and an unidentified phospholipid. Strain VSW210(T) was found to be able to oxidize soluble Mn(II) to insoluble MnO2, which was confirmed with LBB staining. Differential phenotypic properties and genetic uniqueness revealed that this strain VSW210(T) is distinguishable from other species of the genus Citreicella. On the basis of the data presented, strain VSW210(T) is considered to represent a novel species of the genus Citreicella, for which the name Citreicella manganoxidans sp. nov. is proposed. The type strain is VSW210(T) (=KCTC 32497(T) = MCC 2286(T)). PMID:26404429</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24719323','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24719323"><span id="translatedtitle">An internally modulated, thermostable, pH-sensitive Cys loop receptor from the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> worm Alvinella pompejana.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Juneja, Puneet; Horlacher, Reinhold; Bertrand, Daniel; Krause, Ryoko; Marger, Fabrice; Welte, Wolfram</p> <p>2014-05-23</p> <p>Cys loop receptors (CLRs) are commonly known as ligand-gated channels that transiently open upon binding of neurotransmitters to modify the membrane potential. However, a class of cation-selective bacterial homologues of CLRs have been found to open upon a sudden pH drop, suggesting further ligands and more functions of the homologues in prokaryotes. Here we report an anion-selective CLR from the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> annelid worm Alvinella pompejana that opens at low pH. A. pompejana expressed sequence tag databases were explored by us, and two full-length CLR sequences were identified, synthesized, cloned, expressed in Xenopus oocytes, and studied by two-electrode voltage clamp. One channel, named Alv-a1-pHCl, yielded functional receptors and opened upon a sudden pH drop but not by other known agonists. Sequence comparison showed that both CLR proteins share conserved characteristics with eukaryotic CLRs, such as an N-terminal helix, a cysteine loop motif, and an intracellular loop intermediate in length between the long loops of other eukaryotic CLRs and those of prokaryotic CLRs. Both full-length Alv-a1-pHCl and a truncated form, termed tAlv-a1-pHCl, lacking 37 amino-terminal residues that precede the N-terminal helix, formed functional channels in oocytes. After pH activation, tAlv-a1-pHCl showed desensitization and was not modulated by ivermectin. In contrast, pH-activated, full-length Alv-a1-pHCl showed a marked rebound current and was modulated significantly by ivermectin. A thermostability assay indicated that purified tAlv-a1-pHCl expressed in Sf9 cells denatured at a higher temperature than the nicotinic acetylcholine receptor from Torpedo californica. PMID:24719323</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25196437','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25196437"><span id="translatedtitle">Cross-species, amplifiable microsatellite markers for neoverrucid barnacles from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> developed using next-generation sequencing.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nakajima, Yuichi; Shinzato, Chuya; Khalturina, Mariia; Watanabe, Hiromi; Inagaki, Fumio; Satoh, Nori; Mitarai, Satoshi</p> <p>2014-01-01</p> <p>Barnacles of the genus Neoverruca are abundant near deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> of the northwestern Pacific Ocean, and are useful for understanding processes of population formation and maintenance of deep-sea <span class="hlt">vent</span> faunas. Using next-generation sequencing, we isolated 12 polymorphic microsatellite loci from Neoverruca sp., collected in the Okinawa Trough. These microsatellite loci revealed 2-19 alleles per locus. The expected and observed heterozygosities ranged from 0.286 to 1.000 and 0.349 to 0.935, respectively. Cross-species amplification showed that 9 of the 12 loci were successfully amplified for Neoverruca brachylepadoformis in the Mariana Trough. A pairwise FST value calculated using nine loci showed significant genetic differentiation between the two species. Consequently, the microsatellite markers we developed will be useful for further population genetic studies to elucidate genetic diversity, differentiation, classification, and evolutionary processes in the genus Neoverruca. PMID:25196437</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4159855','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4159855"><span id="translatedtitle">Cross-Species, Amplifiable Microsatellite Markers for Neoverrucid Barnacles from Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> Developed Using Next-Generation Sequencing</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Nakajima, Yuichi; Shinzato, Chuya; Khalturina, Mariia; Watanabe, Hiromi; Inagaki, Fumio; Satoh, Nori; Mitarai, Satoshi</p> <p>2014-01-01</p> <p>Barnacles of the genus Neoverruca are abundant near deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> of the northwestern Pacific Ocean, and are useful for understanding processes of population formation and maintenance of deep-sea <span class="hlt">vent</span> faunas. Using next-generation sequencing, we isolated 12 polymorphic microsatellite loci from Neoverruca sp., collected in the Okinawa Trough. These microsatellite loci revealed 2–19 alleles per locus. The expected and observed heterozygosities ranged from 0.286 to 1.000 and 0.349 to 0.935, respectively. Cross-species amplification showed that 9 of the 12 loci were successfully amplified for Neoverruca brachylepadoformis in the Mariana Trough. A pairwise FST value calculated using nine loci showed significant genetic differentiation between the two species. Consequently, the microsatellite markers we developed will be useful for further population genetic studies to elucidate genetic diversity, differentiation, classification, and evolutionary processes in the genus Neoverruca. PMID:25196437</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3564776','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3564776"><span id="translatedtitle">Deep transcriptome-sequencing and proteome analysis of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> annelid Alvinella pompejana identifies the CvP-bias as a robust measure of eukaryotic thermostability</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2013-01-01</p> <p>Background Alvinella pompejana is an annelid worm that inhabits deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> in the Pacific Ocean. Living at a depth of approximately 2500 meters, these worms experience extreme environmental conditions, including high temperature and pressure as well as high levels of sulfide and heavy metals. A. pompejana is one of the most thermotolerant metazoans, making this animal a subject of great interest for studies of eukaryotic thermoadaptation. Results In order to complement existing EST resources we performed deep sequencing of the A. pompejana transcriptome. We identified several thousand novel protein-coding transcripts, nearly doubling the sequence data for this annelid. We then performed an extensive survey of previously established prokaryotic thermoadaptation measures to search for global signals of thermoadaptation in A. pompejana in comparison with mesophilic eukaryotes. In an orthologous set of 457 proteins, we found that the best indicator of thermoadaptation was the difference in frequency of charged versus polar residues (CvP-bias), which was highest in A. pompejana. CvP-bias robustly distinguished prokaryotic thermophiles from prokaryotic mesophiles, as well as the thermophilic fungus Chaetomium thermophilum from mesophilic eukaryotes. Experimental values for thermophilic proteins supported higher CvP-bias as a measure of thermal stability when compared to their mesophilic orthologs. Proteome-wide mean CvP-bias also correlated with the body temperatures of homeothermic birds and mammals. Conclusions Our work extends the transcriptome resources for A. pompejana and identifies the CvP-bias as a robust and widely applicable measure of eukaryotic thermoadaptation. Reviewer This article was reviewed by Sándor Pongor, L. Aravind and Anthony M. Poole. PMID:23324115</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4071572','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4071572"><span id="translatedtitle">Zn-Driven Discovery of a <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Fungal Metabolite Clavatustide C, and an Experimental Study of the Anti-Cancer Mechanism of Clavatustide B</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ye, Panpan; Shen, Ling; Jiang, Wei; Ye, Ying; Chen, Chen-Tung Arthur; Wu, Xiaodan; Wang, Kuiwu; Wu, Bin</p> <p>2014-01-01</p> <p>A naturally new cyclopeptide, clavatustide C, was produced as a stress metabolite in response to abiotic stress elicitation by one of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluid components Zn in the cultured mycelia of Aspergillus clavatus C2WU, which were isolated from Xenograpsus testudinatus. X. testudinatus lives at extreme, toxic habitat around the sulphur-rich <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in Taiwan Kueishantao. The known compound clavatustide B was also isolated and purified. This is the first example of a new <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> microbial secondary metabolite produced in response to abiotic Zn treatment. The structures were established by spectroscopic means. The regulation of G1-S transition in hepatocellular carcinoma cell lines by clavatustide B was observed in our previous study. The purpose of the present study was to verify these results in other types of cancer cell lines and elucidate the possible molecular mechanism for the anti-cancer activities of clavatustide B. In different human cancer cell lines, including pancreatic cancer (Panc-1), gastric cancer (MGC-803), colorectal cancer (SW-480), retinoblastoma (WERI-Rb-1) and prostate cancer (PC3), clavatustide B efficiently suppressed cell proliferations in a dose-dependent manner. Although different cancer cell lines presented variety in Max effect dose and IC50 dose, all cancer cell lines showed a lower Max effect dose and IC50 dose compared with human fibroblasts (hFB) (p < 0.05). Moreover, significant accumulations in G1 phases and a reduction in S phases (p < 0.05) were observed under clavatustide B treatment. The expression levels of 2622 genes including 39 cell cycle-associated genes in HepG2 cells were significantly altered by the treatment with 15 ?g/mL clavatustide B after 48 h. CCNE2 (cyclin E2) was proved to be the key regulator of clavatustide B-induced G1-S transition blocking in several cancer cell lines by using real-time PCR. PMID:24879544</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.B21A0326T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.B21A0326T"><span id="translatedtitle">Seismic activity associated with temperature perturbations at Bio 9 <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> on the East Pacific Rise at 9deg50'N</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tolstoy, M.; Crone, T. J.; Felix, W.; Bohnenstiehl, D. R.; Fornari, D. J.; von Damm, K.</p> <p>2008-12-01</p> <p>A brief seismic swarm north of high temperature <span class="hlt">vent</span> Bio 9 on November 19th 2003 appears to have triggered a temperature response on a time scale of ~3 days, similar to previously observed events (Sohn et al., 1998; Wilcock, 2004). Temperatures initially rose by ~5degC over the course of 10 days and then fell by ~14degC over 8 days, before gradually recovering to temperatures slightly higher than before the event over the following 2-3 months. Near-by chimneys showed small or no response to this event suggesting that fluid pathways to individual <span class="hlt">vents</span> are narrowly defined deep within the crust. The seismic swarm of ~130 relocated events forms a thin near-vertical line approximately 1 km tall with evidence of upward propagation from directly above the axial magma chamber to the top of <span class="hlt">hydrothermal</span> cracking zone and into the interpreted upflow zone. The earthquakes initiate from an area close to the events associated with a similar temperature perturbation at Bio 9 in 1994 (Sohn et al., 1998), suggesting that fluid pathways are maintained on decadal time scales. However, the character of the temperature perturbation is different from the 1994 event in that after initially rising, temperatures decline to below pre- swarm level before recovering gradually. This may reflect a different phase in the evolution of the <span class="hlt">hydrothermal</span> cell, since temperatures at Bio 9 in 2003 were higher and more stable than they were in 1994. The interpreted <span class="hlt">hydrothermal</span> cell beneath Bio 9 shows a decrease in seismic b-value following recovery of the Bio 9 temperatures. A decrease in b-value may reflect an increase in stress, lower pore pressures, or variation in the distribution of fractures within the rock. Analysis of the seismic swarm within the context of the interpreted <span class="hlt">hydrothermal</span> cell and previous seismic results will be presented, and possible models for triggering the temperature perturbations will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7177372','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/7177372"><span id="translatedtitle">Pb isotopes in sulfides from mid-ocean ridge <span class="hlt">hydrothermal</span> <span class="hlt">sites</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>LeHuray, A.P.; Church, S.E.; Koski, R.A.; Bouse, R.M.</p> <p>1988-04-01</p> <p>The authors report Pb isotope ratios of sulfides deposited at seven recently active mid-ocean ridge (MOR) <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Sulfides from three sediment-starved <span class="hlt">sites</span> on the Juan de Fuca Ridge contain Pb with isotope ratios identical to their local basaltic sources. Lead in two deposits from the sediment-covered Escanaba Trough, Gorda Ridge, is derived from the sediments and does not appear to contain any basaltic component. There is a range of isotope ratios in a Guaymas Basin deposit, consistent with a mixture of sediment and MOR basalt Pb. Lead in a Galapagos deposit differs slightly from known Galapagos basalt Pb isotope values. The faithful record of Pb isotope signatures of local sources in MOR sulfides indicates that isotope ratios from ancient analogues ca be used as accurate reflections of ancient oceanic crustal values in ophiolite-hosted deposits and continental crustal averages in sediment-hosted deposits. The preservation of primary ophiolitic or continental crustal Pb isotope signatures in ancient MOR sulfides provides a powerful tool for investigation of crustal evolution and for fingerprinting ancient terranes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUSMOS31A..03R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUSMOS31A..03R"><span id="translatedtitle">A role of sulfur in 'black smoker' sedimentary matter evolution. Illustration: the TAG and Broken Spur <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields (Mid-Atlantic Ridge)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rusakov, V. Y.</p> <p>2006-05-01</p> <p>Numerous direct observations of known <span class="hlt">vents</span> on the sea-bottom showed that formation of massive sulfide deposits has complicated and intricate story. We suggest that the matter, forming by direct contact between <span class="hlt">hydrothermal</span> fluid and sea-water, gives useful information on genesis and evolution for ancient volcanic massive sulfide (VMS) deposits. In the Atlantic Ocean, <span class="hlt">hydrothermal</span> particle matter collected by means of sediment traps near black smokers have been studied only within the Broken Spur [Lukashin et al., 1999] and TAG fields. Chemical and mineral composition of the particulate matter from the TAG field we discuss for the first time. Sediment traps are widely used for collecting free-sinking particles in the water column because of their design and easiness in operation. Besides, it is easy to calculate the flux if one knows the mass of trapped material, the aperture area of the trap, and the exposure time. In addition, this method makes it possible to sample the substance in the water column and to study it in the pure state (to determine mineral and chemical composition). In order to research the particulate matter and its flux near black smokers (the main problem is that the trap also collected some undesired material from another layers of the water column), our traps (KSL-400/1) were provided with special mechanism that protect a sample from "contamination" [Rusakov et al., 1996]. Two such traps were deployed with the help of manned submersible "MIR" on the sea- bottom at a distance 3 meters from basement of 'black smoker' chimney complex. First trap was near the Saracen's Head (the most massive 'black smoker' chimney of the Broken Spur field). Second one was on the top of the TAG Mound. Both fields have identical type of circulating system (axial circulating system of the low-spreading ridge) and identical source of chemical elements - toleitic basalts. Differences are concerned only the age of the <span class="hlt">vents</span>. The results showed that the material in both cases has high contents of ore-forming chemical elements (Fe, Cu, Zn), as well as Se, As, Sb, Ba and P relatively to both pelagic sediments and basaltic rocks from that they were leached. 40 percent of particulate matter near more "old" <span class="hlt">vent</span> on TAG field (40-50 kyr) consists of Fe-oxyhydroxide particles in contrast with the Broken Spur <span class="hlt">vent</span> (< 1 kyr), where pyrrhotite is a dominant mineral. We propose that this difference is the result of sulfur deficit in <span class="hlt">hydrothermal</span> fluid in older <span class="hlt">vent</span> on the TAG field. That could be a result both decrease of sulfur content in oceanic crust and sulfur expenditure for mineralization within ore body. Higher enrichment factors for S, Se and Ca relatively to toleitic basalts for <span class="hlt">vent</span> on the Broken Spur field may be explained by higher mobility of these elements, which were leached more intensively from rocks of reaction zone in early stages of the <span class="hlt">hydrothermal</span> system evolution. Higher enrichment factors for Cu, Fe, Zn in the material of the TAG <span class="hlt">vent</span> and, specially, for As and Si (in 3 and 5 times more than material from the Broken Spur <span class="hlt">vent</span>, correspondingly), obviously, are the result of their lower mobility. It was showed in the Logachev I and II fields that <span class="hlt">hydrothermal</span> iron may also be washed out from ore body as a result of substitution: Cu+Fe2+Fe3+S3 (isocubanite) - Cu+Fe3+S2 (chalcopyrite) - Cu5+Fe3+S4 (bornite) [Mozgova et al., 2005]. Besides, it was determined that about 67 tons of particulate iron are contained in plume body above the TAG <span class="hlt">vent</span> field by volume about 6 km3, and 23.5 tons of particulate iron are contained in plume above the Broken Spur <span class="hlt">vent</span> field by volume 8.24 km3 [Rusakov, 2006]. We speculate that such difference is the result of higher <span class="hlt">hydrothermal</span> iron supply into the water column from the TAG <span class="hlt">vent</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26684507','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26684507"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> Conditions and the Origin of Cellular Life.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Deamer, David W; Georgiou, Christos D</p> <p>2015-12-01</p> <p>The conditions and properties of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> and <span class="hlt">hydrothermal</span> fields are compared in terms of their ability to support processes related to the origin of life. The two <span class="hlt">sites</span> can be considered as alternative hypotheses, and from this comparison we propose a series of experimental tests to distinguish between them, focusing on those that involve concentration of solutes, self-assembly of membranous compartments, and synthesis of polymers. Key Word: <span class="hlt">Hydrothermal</span> systems. Astrobiology 15, 1091-1095. PMID:26684507</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2885270','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2885270"><span id="translatedtitle">Bacterial Lifestyle in a Deep-sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Chimney Revealed by the Genome Sequence of the Thermophilic Bacterium Deferribacter desulfuricans SSM1</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Takaki, Yoshihiro; Shimamura, Shigeru; Nakagawa, Satoshi; Fukuhara, Yasuo; Horikawa, Hiroshi; Ankai, Akiho; Harada, Takeshi; Hosoyama, Akira; Oguchi, Akio; Fukui, Shigehiro; Fujita, Nobuyuki; Takami, Hideto; Takai, Ken</p> <p>2010-01-01</p> <p>The complete genome sequence of the thermophilic sulphur-reducing bacterium, Deferribacter desulfuricans SMM1, isolated from a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimney has been determined. The genome comprises a single circular chromosome of 2 234 389 bp and a megaplasmid of 308 544 bp. Many genes encoded in the genome are most similar to the genes of sulphur- or sulphate-reducing bacterial species within Deltaproteobacteria. The reconstructed central metabolisms showed a heterotrophic lifestyle primarily driven by C1 to C3 organics, e.g. formate, acetate, and pyruvate, and also suggested that the inability of autotrophy via a reductive tricarboxylic acid cycle may be due to the lack of ATP-dependent citrate lyase. In addition, the genome encodes numerous genes for chemoreceptors, chemotaxis-like systems, and signal transduction machineries. These signalling networks may be linked to this bacterium's versatile energy metabolisms and may provide ecophysiological advantages for D. desulfuricans SSM1 thriving in the physically and chemically fluctuating environments near <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. This is the first genome sequence from the phylum Deferribacteres. PMID:20189949</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3385714','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3385714"><span id="translatedtitle">Exploring the limit of metazoan thermal tolerance via comparative proteomics: thermally induced changes in protein abundance by two <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> polychaetes</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Dilly, Geoffrey F.; Young, C. Robert; Lane, William S.; Pangilinan, Jasmyn; Girguis, Peter R.</p> <p>2012-01-01</p> <p>Temperatures around <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are highly variable, ranging from near freezing up to 300°C. Nevertheless, animals thrive around <span class="hlt">vents</span>, some of which live near the known limits of animal thermotolerance. Paralvinella sulfincola, an extremely thermotolerant <span class="hlt">vent</span> polychaete, and Paralvinella palmiformis, a cooler-adapted congener, are found along the Juan de Fuca Ridge in the northwestern Pacific. We conducted shipboard high-pressure thermotolerance experiments on both species to characterize the physiological adaptations underlying P. sulfincola's pronounced thermotolerance. Quantitative proteomics, expressed sequence tag (EST) libraries and glutathione assays revealed that P. sulfincola (i) exhibited an upregulation in the synthesis and recycling of glutathione with increasing temperature, (ii) downregulated nicotinamide adenine dinucleotide (NADH) and succinate dehydrogenases (key enzymes in oxidative phosphorylation) with increasing temperature, and (iii) maintained elevated levels of heat shock proteins (HSPs) across all treatments. In contrast, P. palmiformis exhibited more typical responses to increasing temperatures (e.g. increasing HSPs at higher temperatures). These data reveal differences in how a mesotolerant and extremely thermotolerant eukaryote respond to thermal stress, and suggest that P. sulfincola's capacity to mitigate oxidative stress via increased synthesis of antioxidants and decreased flux through the mitochondrial electron transport chain enable pronounced thermotolerance. Ultimately, oxidative stress may be the key factor in limiting all metazoan thermotolerance. PMID:22553092</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=61713&keyword=recycling+AND+data&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=52405985&CFTOKEN=98084789','EPA-EIMS'); return false;" href="http://cfpub.epa.gov/si/si_public_record_report.cfm?dirEntryId=61713&keyword=recycling+AND+data&actType=&TIMSType=+&TIMSSubTypeID=&DEID=&epaNumber=&ntisID=&archiveStatus=Both&ombCat=Any&dateBeginCreated=&dateEndCreated=&dateBeginPublishedPresented=&dateEndPublishedPresented=&dateBeginUpdated=&dateEndUpdated=&dateBeginCompleted=&dateEndCompleted=&personID=&role=Any&journalID=&publisherID=&sortBy=revisionDate&count=50&CFID=52405985&CFTOKEN=98084789"><span id="translatedtitle">STATISTICAL SAMPLING APPROACH FOR CLOSING A SOIL <span class="hlt">VENTING</span> <span class="hlt">SITE</span></span></a></p> <p><a target="_blank" href="http://oaspub.epa.gov/eims/query.page">EPA Science Inventory</a></p> <p></p> <p></p> <p>The USEPA allowed the Performing Parties (PPs) to perform a soil vapor extraction process to a <span class="hlt">site</span> contaminated by volatile organic compounds (VOC), contingent upon the process reducing the VOC concentrations in the soil by 75% within one year. An innovative injection-extraction...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/87059','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/87059"><span id="translatedtitle">Passive soil <span class="hlt">venting</span> at the Chemical Waste Landfill <span class="hlt">Site</span> at Sandia National Laboratories, Albuquerque, New Mexico</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Phelan, J.M.; Reavis, B.; Cheng, W.C.</p> <p>1995-05-01</p> <p>Passive Soil Vapor Extraction was tested at the Chemical Waste Landfill (CWL) <span class="hlt">site</span> at Sandia National Laboratories, New Mexico (SNLIW). Data collected included ambient pressures, differential pressures between soil gas and ambient air, gas flow rates into and out of the soil and concentrations of volatile organic compounds (VOCS) in <span class="hlt">vented</span> soil gas. From the differential pressure and flow rate data, estimates of permeability were arrived at and compared with estimates from other studies. Flow, differential pressure, and ambient pressure data were collected for nearly 30 days. VOC data were collected for two six-hour periods during this time. Total VOC emissions were calculated and found to be under the limit set by the Resource Conservation and Recovery Act (RCRA). Although a complete process evaluation is not possible with the data gathered, some of the necessary information for designing a passive <span class="hlt">venting</span> process was determined and the important parameters for designing the process were indicated. More study is required to evaluate long-term VOC removal using passive <span class="hlt">venting</span> and to establish total remediation costs when passive <span class="hlt">venting</span> is used as a polishing process following active soil vapor extraction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://alrlab.pdx.edu/media/PNAsNakagawa.pdf','EPRINT'); return false;" href="http://alrlab.pdx.edu/media/PNAsNakagawa.pdf"><span id="translatedtitle">Deep-sea <span class="hlt">vent</span> -proteobacterial genomes provide insights into emergence of pathogens</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Reysenbach, Anna-Louise</p> <p></p> <p>for <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> -Proteobacteria who thrive in their deep-sea habitat and are essential for both the efficient-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> pathogenesis symbiosis Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are areas on the sea floor of high- or endo- symbionts of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> invertebrates (3­6) and free- living organisms associated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/316286','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/316286"><span id="translatedtitle">Fine-scale heat flow, shallow heat sources, and decoupled circulation systems at two sea-floor <span class="hlt">hydrothermal</span> <span class="hlt">sites</span>, Middle Valley, northern Juan de Fuca Ridge</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Stein, J.S.; Fisher, A.T.; Langseth, M.; Jin, W.; Iturrino, G.; Davis, E.</p> <p>1998-12-01</p> <p>Fine-scale heat-flow patterns at two areas of active <span class="hlt">venting</span> in Middle Valley, a sedimented rift on the northern Juan de Fuca Ridge, provide thermal evidence of shallow <span class="hlt">hydrothermal</span> reservoirs beneath the <span class="hlt">vent</span> fields. The extreme variability of heat flow is explained by conductive heating immediately adjacent to <span class="hlt">vents</span> and shallow circulation within sediments above the reservoir. This secondary circulation is hydrologically separated from the deeper system feeding the <span class="hlt">vents</span> by a shallow conductive lid within the sediments. A similar separation of shallow and deep circulation may also occur at sediment-free ridge-crest <span class="hlt">hydrothermal</span> environments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMOS24A..08T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS24A..08T"><span id="translatedtitle">Transfer and partitioning of energy and mass through seafloor <span class="hlt">hydrothermal</span> systems: comparative studies at the Ridge2000 Integrated Study <span class="hlt">Sites</span> (ISS) (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tivey, M. K.</p> <p>2010-12-01</p> <p>Seafloor <span class="hlt">hydrothermal</span> systems are major players in the transfer of mass and energy from the mantle and crust to the ocean and biosphere. Over the past thirty years, much has been learned about this transfer to the ocean, but considerably less is known about the transfer to the biosphere. Study of <span class="hlt">hydrothermal</span> systems in a diverse range of geologic settings has shown relationships between spreading rate and <span class="hlt">hydrothermal</span> heat flux, substrate composition (including rock geochemistry, presence/absence of sediment) and <span class="hlt">hydrothermal</span> fluid composition, and magmatic/tectonic events and temporal variability of fluid composition (e.g., German and Von Damm, Treatise On Geochemistry, 2004; Baker et al. AGU Monograph Series 91, 1995). Studies in arc and back-arc settings are documenting the effects of magmatic acid volatiles on fluid-rock reaction and fluid and <span class="hlt">vent</span> deposit compositions (e.g., Ishibashi and Urabe, Backarc Basins: Tectonics and Magmatism, 1995). These comparative studies in a wide range of geologic settings, including at the three Ridge2000 ISS, have provided a fairly good understanding of the flux of heat and many elements to the ocean associated with high temperature seafloor <span class="hlt">hydrothermal</span> systems. Considerably less is known, however, about the partitioning of heat and mass (particularly metals and sulfur) in <span class="hlt">hydrothermal</span> systems. The deposits that form at <span class="hlt">vent</span> <span class="hlt">sites</span> are intimately linked within paths of energy and mass transport from the mantle and crust to the oceans. Transport differs greatly through different types of deposits (e.g., black smokers, white smokers/diffusers, flanges). Estimates of heat flux from measured temperatures of flow (unless integrated over and around an entire <span class="hlt">vent</span> field) require an understanding of the partitioning of flow between focused black smokers and more diffuse flow from diffusers, flanges, and surfaces of deposits, and from the igneous substrate. Estimates of mass flux into the ocean require an understanding of the temperature-composition paths taken by fluids, and the extent to which some elements (e.g., Cu, Fe, Zn, Ba, S) are partitioned between deposits and plumes. Precipitation efficiency differs depending on the vigor of <span class="hlt">venting</span> and fluid composition (e.g., pH), which (in part) determines the prevalence of black smoker activity versus flow through diffusers and flanges (e.g., review in Tivey, Oceanography, 2007). Quantification of this partitioning is further complicated by apparent differences in ages of accumulated deposits in different <span class="hlt">vent</span> fields. An unknown at many <span class="hlt">vent</span> fields is the length of time and duration of activity responsible for forming the existing deposits, and the extent to which large size is a result of efficient precipitation versus time. For biota, the different styles of fluid flow through the substrate and different parts of deposits affect thermal and chemical environments in plumes, as well as on, and just inside, deposit exteriors. As with our understanding of mass and energy transfer to the ocean, we can make significant advances in our understanding of this partitioning of energy and mass through comparative studies of <span class="hlt">hydrothermal</span> systems in a diverse range of geologic settings (e.g., at the three Ridge2000 ISS).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25462464','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25462464"><span id="translatedtitle">Post-capture immune gene expression studies in the deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel Bathymodiolus azoricus acclimatized to atmospheric pressure.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Barros, Inês; Divya, Baby; Martins, Inês; Vandeperre, Frederic; Santos, Ricardo Serrão; Bettencourt, Raul</p> <p>2015-01-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are extreme habitats that are distributed worldwide in association with volcanic and tectonic events, resulting thus in the establishment of particular environmental conditions, in which high pressure, steep temperature gradients, and potentially toxic concentrations of sulfur, methane and heavy metals constitute driving factors for the foundation of chemosynthetic-based ecosystems. Of all the different macroorganisms found at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, the mussel Bathymodiolus azoricus is the most abundant species inhabiting the <span class="hlt">vent</span> ecosystems from the Mid-Atlantic Ridge (MAR). In the present study, the effect of long term acclimatization at atmospheric pressure on host-symbiotic associations were studied in light of the ensuing physiological adaptations from which the immune and endosymbiont gene expressions were concomitantly quantified by means of real-time PCR. The expression of immune genes at 0 h, 12 h, 24 h, 36 h, 48 h, 72 h, 1 week and 3 weeks post-capture acclimatization was investigated and their profiles compared across the samples tested. The gene signal distribution for host immune and bacterial genes followed phasic changes in gene expression at 24 h, 1 week and 3 weeks acclimatization when compared to other time points tested during this temporal expression study. Analyses of the bacterial gene expression also suggested that both bacterial density and activity could contribute to shaping the intricate association between endosymbionts and host immune genes whose expression patterns seem to be concomitant at 1 week acclimatization. Fluorescence in situ hybridization was used to assess the distribution and prevalence of endosymbiont bacteria within gill tissues confirming the gradual loss of sulfur-oxidizing (SOX) and methane-oxidizing (MOX) bacteria during acclimatization. The present study addresses the deep-sea <span class="hlt">vent</span> mussel B. azoricus as a model organism to study how acclimatization in aquaria and the prevalence of symbiotic bacteria are driving the expression of host immune genes. Tight associations, unseen thus far, suggest that host immune and bacterial gene expression patterns reflect distinct physiological responses over the course of acclimatization under aquarium conditions. PMID:25462464</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70027317','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70027317"><span id="translatedtitle">Gas geochemistry of a shallow submarine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> associated with the El Requesón fault zone, Bahía Concepción, Baja California Sur, México</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Forrest, Matthew J.; Ledesma-Vazquez, Jorge; Ussler, William, III; Kulongoski, Justin T.; Hilton, David R.; Greene, H. Gary</p> <p>2005-01-01</p> <p>We investigated <span class="hlt">hydrothermal</span> gas <span class="hlt">venting</span> associated with a coastal fault zone along the western margin of Bahía Concepción, B.C.S., México. Copious discharge of geothermal liquid (? 90 °C) and gas is occurring in the intertidal and shallow subtidal zones (to a depth of 13 m) through soft sediments and fractures in rocks along a ?750 m linear trend generally sub-parallel to an onshore fault near Punta Santa Barbara. <span class="hlt">Hydrothermal</span> activity shows negative correlation with tidal height; temperatures in the area of <span class="hlt">hydrothermal</span> activity were up to 11.3 °C higher at low tide than at high tide (measured tidal range ? 120 cm). Gas samples were collected using SCUBA and analyzed for chemical composition and stable isotope values. The main components of the gas are N2 (? 53%; 534 mmol/mol), CO2 (? 43%; 435 mmol/mol), and CH4 (? 2.2%; 22 mmol/mol). The ?13C values of the CH4 (mean = ? 34.3‰), and the ratios of CH4 to C2H6(mean = 89), indicate that the gas is thermogenic in origin. The carbon stable isotopes and the ?15N of the N2 in the gas (mean = 1.7‰) suggest it may be partially derived from the thermal alteration of algal material in immature sedimentary organic matter. The He isotope ratios (3He / 4He = 1.32 RA) indicate a significant mantle component (16.3%) in the gas. Here, we suggest the name El Requesón fault zone for the faults that likely formed as a result of extension in the region during the late Miocene, and are currently serving as conduits for the observed <span class="hlt">hydrothermal</span> activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1049869','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1049869"><span id="translatedtitle">Complete genome sequence of the aerobic, heterotroph Marinithermus hydrothermalis type strain (T1T) from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimney</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Copeland, A; Gu, Wei; Yasawong, Montri; Lapidus, Alla L.; Lucas, Susan; Deshpande, Shweta; Pagani, Ioanna; Tapia, Roxanne; Cheng, Jan-Fang; Goodwin, Lynne A.; Pitluck, Sam; Liolios, Konstantinos; Ivanova, N; Mavromatis, K; Mikhailova, Natalia; Pati, Amrita; Chen, Amy; Palaniappan, Krishna; Land, Miriam L; Pan, Chongle; Brambilla, Evelyne-Marie; Rohde, Manfred; Tindall, Brian; Sikorski, Johannes; Goker, Markus; Detter, J. Chris; Bristow, James; Eisen, Jonathan; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter; Woyke, Tanja</p> <p>2012-01-01</p> <p>Marinithermus hydrothermalis Sako et al. 2003 is the type species of the monotypic genus Marinithermus. M. hydrothermalis T1 T was the first isolate within the phylum ThermusDeinococcus to exhibit optimal growth under a salinity equivalent to that of sea water and to have an absolute requirement for NaCl for growth. M. hydrothermalis T1 T is of interest because it may provide a new insight into the ecological significance of the aerobic, thermophilic decomposers in the circulation of organic compounds in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystems. This is the first completed genome sequence of a member of the genus Marinithermus and the seventh sequence from the family Thermaceae. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 2,269,167 bp long genome with its 2,251 protein-coding and 59 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006DSRI...53..894T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006DSRI...53..894T"><span id="translatedtitle">Autonomous Microbial Sampler (AMS), a device for the uncontaminated collection of multiple microbial samples from submarine <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> and other aquatic environments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Taylor, Craig D.; Doherty, Kenneth W.; Molyneaux, Stephen J.; Morrison, Archie T.; Billings, John D.; Engstrom, Ivory B.; Pfitsch, Don W.; Honjo, Susumu</p> <p>2006-05-01</p> <p>An Autonomous Microbial Sampler (AMS) is described that will obtain uncontaminated and exogenous DNA-free microbial samples from most marine, freshwater and <span class="hlt">hydrothermal</span> ecosystems. Sampling with the AMS may be conducted using manned submersibles, remotely operated vehicles (ROVs), autonomous underwater vehicles (AUVs), or when tethered to a hydrowire during hydrocast operations on research vessels. The modular device consists of a titanium nozzle for sampling in potentially hot environments (>350 °C) and fluid-handling components for the collection of six independent filtered or unfiltered samples. An onboard microcomputer permits sampling to be controlled by the investigator, by external devices (e.g., AUV computer), or by internal programming. Temperature, volume pumped and other parameters are recorded during sampling. Complete protection of samples from microbial contamination was observed in tests simulating deployment of the AMS in coastal seawater, where the sampling nozzle was exposed to seawater containing 1×10 6 cells ml -1 of a red pigmented tracer organism, Serratia marinorubra. Field testing of the AMS at a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field was successfully undertaken in 2000. Results of DNA destruction studies have revealed that exposure of samples of the Eukaryote Euglena and the bacterium S. marinorubra to 0.5 N sulfuric acid at 23 °C for 1 h was sufficient to remove polymerase chain reaction (PCR) amplifiable DNA. Studies assessing the suitability of hydrogen peroxide as a sterilizing and DNA-destroying agent showed that 20% or 30% hydrogen peroxide sterilized samples of Serratia in 1 h and destroyed the DNA of Serratia in 3 h, but not 1 or 2 h. DNA AWAY™ killed Serratia and destroyed the DNA of both Serratia and the <span class="hlt">vent</span> microbe (GB-D) of the genus Pyrococcus in 1 h.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26710075','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26710075"><span id="translatedtitle">Morphology of First Zoeal Stage of Four Genera of Alvinocaridid Shrimps from <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> and Cold Seeps: Implications for Ecology, Larval Biology and Phylogeny.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hernández-Ávila, Iván; Cambon-Bonavita, Marie-Anne; Pradillon, Florence</p> <p>2015-01-01</p> <p>Alvinocaridid shrimps are endemic species inhabiting <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> and/or cold seeps. Although indirect evidences (genetic and lipid markers) suggest that their larval stages disperse widely and support large scale connectivity, larval life and mechanisms underlying dispersal are unknown in alvinocaridids. Here we provide for the first time detailed descriptions of the first larval stage (zoea I) of four alvinocaridid species: Rimicaris exoculata and Mirocaris fortunata from the Mid-Atlantic Ridge, Alvinocaris muricola from the Congo Basin and Nautilocaris saintlaurentae from the Western Pacific. The larvae were obtained from onboard hatching of brooding females (either at atmospheric pressure or at habitat pressure in hyperbaric chambers) and from the water column near adult habitats, sampled with plankton pumps or sediment traps. Major characteristics of the alvinocaridid larvae include undeveloped mandible and almost complete absence of setation in the inner margin of the mouth parts and maxillipeds. Although the larvae are very similar between the four species studied, some morphological features could be used for species identification. In addition, undeveloped mouthparts and the large amount of lipid reserves strongly support the occurrence of primary lecithotrophy in the early stage of alvinocaridids. Although lecithotrophy in decapod crustaceans is usually associated with abbreviated larval development, as a mechanism of larval retention, morphological and physiological evidences suggest the occurrence of an extended and lecithotrophic larval stage in the Alvinocarididae. These traits permit the colonization of widely dispersed and fragmented environments of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> and cold seeps. Distribution of larval traits along the phylogenetic reconstruction of the Alvinocarididae and related families suggest that lecithotrophy/planktotrophy and extended/abbreviated development have evolved independently along related families in all potential combinations. However, the Alvinocarididae is the only taxa with a combination of lecithotrophy and extended larval development. PMID:26710075</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1389210','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1389210"><span id="translatedtitle">Distribution of Microorganisms in Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Chimneys Investigated by Whole-Cell Hybridization and Enrichment Culture of Thermophilic Subpopulations</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Harmsen, H.; Prieur, D.; Jeanthon, C.</p> <p>1997-01-01</p> <p>The microbial community structure of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimneys was evaluated by the combined use of enrichment cultures and whole-cell hybridizations with fluorescently labeled 16S rRNA-based oligonucleotide probes. Chimneys were collected during the Microsmoke cruise on the Mid-Atlantic Ridge and were subsampled on board and stored under reduced conditions or fixed. For estimation of culturable thermophiles, selective media were inoculated by dilution series of the samples and incubated at 65, 80, and 95(deg)C. To analyze the microbial diversity of the samples, cells were extracted from the fixed chimney structure samples and hybridized with domain- and kingdom-specific probes. Quantification of the extracted cells was assessed by whole-cell hybridization on membrane filters. By both methods, the largest amounts of microorganisms were found in the upper and outer parts of the chimneys, although even the inner parts contained culturable and detectable amounts of cells. Different morphotypes of thermophilic and hyperthermophilic microorganisms were enriched and detected in samples. Our data clearly indicate that the morphological diversity observed by using whole-cell hybridization is much larger than that assessed by use of culture-based enrichments. This new approach, including culture-independent and -dependent methods to study <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimneys, showed an uneven distribution of a diverse microbial community. Application of lower-level specific probes for known families and genera within each domain by our approach will be useful to reveal the real extent and nature of the chimney microbial diversity and to support cultivation attempts. PMID:16535655</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12713468','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12713468"><span id="translatedtitle">A delta13C-based carbon flux model for the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chemoautotrophic symbiosis Riftia pachyptila predicts sizeable CO(2) gradients at the host-symbiont interface.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Scott, Kathleen M</p> <p>2003-05-01</p> <p>The chemoautotrophic symbiosis Riftia pachyptila has extremely 13C-enriched delta13C values. Neither isotopic discrimination by the RubisCO enzyme of their bacterial endosymbionts, nor the delta13C value of CO2 at their <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> habitat, suffice to explain biomass delta13C values in this organism, which range from - 9 to - 16 per thousand. However, these 13C-enriched delta13C values are consistent with the presence of 13C-enriched CO2 within the symbiont cytoplasm. Such a 13C-enriched pool of CO2 is expected when the rate of CO2 fixation by RubisCO, which fixes 12CO2 more rapidly than 13CO2, approaches the rate of exchange between intracellular and extracellular CO2 pools. Rapid CO2 fixation rates will also generate concentration gradients between these two pools. In order to estimate the size of these concentration gradients, an equation was derived, which describes the delta13C of tubeworm biomass in terms of the size of the CO2 gradient between the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environment and the symbiont cytoplasm. Using mass balance equations for CO2 exchange and fixation by the symbionts and the tubeworm host, this model predicts that a CO2 concentration gradient of up to 17-fold between the symbiont cytoplasm and the environment is sufficient to explain even the most 13C-enriched R. pachyptila biomass. This model illustrates how both physical and enzymatic factors can act to influence the delta13C of intracellular CO2, which, in turn, highlights the danger of assigning a carbon fixation pathway to an autotroph based solely on its biomass delta13C value. PMID:12713468</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.lpi.usra.edu/nuggets/2015/nugget_cassini-geyser_dust_from_enceladus_20150313.pdf','EPRINT'); return false;" href="http://www.lpi.usra.edu/nuggets/2015/nugget_cassini-geyser_dust_from_enceladus_20150313.pdf"><span id="translatedtitle">Telltale Geyser Dust from Enceladus Seafloor <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Rathbun, Julie A.</p> <p></p> <p><span class="hlt">hydrothermal</span> activity is occurring. · Similar activity is observed around mid-Atlantic seafloor <span class="hlt">vents</span>, whereTelltale Geyser Dust from Enceladus Seafloor <span class="hlt">Vents</span> Cassini discovers the first evidence for ongoing seafloor <span class="hlt">hydrothermal</span> activity on a body other than Earth. <span class="hlt">Hydrothermal</span> activity occurs when seawater</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20660317','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20660317"><span id="translatedtitle">Diverse styles of submarine <span class="hlt">venting</span> on the ultraslow spreading Mid-Cayman Rise.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>German, C R; Bowen, A; Coleman, M L; Honig, D L; Huber, J A; Jakuba, M V; Kinsey, J C; Kurz, M D; Leroy, S; McDermott, J M; de Lépinay, B Mercier; Nakamura, K; Seewald, J S; Smith, J L; Sylva, S P; Van Dover, C L; Whitcomb, L L; Yoerger, D R</p> <p>2010-08-10</p> <p>Thirty years after the first discovery of high-temperature submarine <span class="hlt">venting</span>, the vast majority of the global mid-ocean ridge remains unexplored for <span class="hlt">hydrothermal</span> activity. Of particular interest are the world's ultraslow spreading ridges that were the last to be demonstrated to host high-temperature <span class="hlt">venting</span> but may host systems particularly relevant to prebiotic chemistry and the origins of life. Here we report evidence for previously unknown, diverse, and very deep <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> along the approximately 110 km long, ultraslow spreading Mid-Cayman Rise (MCR). Our data indicate that the MCR hosts at least three discrete <span class="hlt">hydrothermal</span> <span class="hlt">sites</span>, each representing a different type of water-rock interaction, including both mafic and ultramafic systems and, at approximately 5,000 m, the deepest known <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>. Although submarine <span class="hlt">hydrothermal</span> circulation, in which seawater percolates through and reacts with host lithologies, occurs on all mid-ocean ridges, the diversity of <span class="hlt">vent</span> types identified here and their relative geographic isolation make the MCR unique in the oceans. These new <span class="hlt">sites</span> offer prospects for an expanded range of <span class="hlt">vent</span>-fluid compositions, varieties of abiotic organic chemical synthesis and extremophile microorganisms, and unparalleled faunal biodiversity--all in close proximity. PMID:20660317</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25113370','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25113370"><span id="translatedtitle">Vulcanolepas scotiaensis sp. nov., a new deep-sea scalpelliform barnacle (Eolepadidae: Neolepadinae) from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the Scotia Sea, Antarctica.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Buckeridge, John S; Linse, Katrin; Jackson, Jennifer A</p> <p>2013-01-01</p> <p>A new deep-sea stalked barnacle, Vulcanolepas scotiaensis sp. nov. is described from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> at depths of 2400-2600 metres along segments of the East Scotia Ridge and from 1400 metres in the Kemp Caldera. Both locations are areas of volcanic activity that lie on the Antarctic-South American Ocean Ridge complex near the South Sandwich Islands. This discovery confirms a wide distribution in southern seas for Vulcanolepas, complementing the previous records from deep-sea <span class="hlt">vents</span> in the Lau Basin and Kermadec Ridge in the southwest Pacific, and the Pacific Antarctic Ridge in the southeast Pacific. V. scotiaensis sp. nov., the third described species of Vulcanolepas shows an extraordinary range in morphology, requiring a reassessment of the original diagnosis for Vulcanolepas. Although the morphological envelope of V. scotiaensis sp. nov. includes representatives with a peduncle to capitulum ratio similar to that observed in most neolepadines, the peduncle generally shows greater proportional length than in species in any neolepadine genus except Leucolepas; it is distinguished from other species of Vulcanolepas by a broader capitulum, much smaller imbricating scales on the peduncle and more ornamented capitulum plates. The morphological diversity of V. scotiaensis sp. nov. is interpreted as having arisen due to abrupt changes in water temperature.LSID: urn:lsid:zoobank.org:act:AA2AFDA5-0B08-466A-A584-D3FDBDE9DA61. PMID:25113370</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ccmar.ualg.pt/maree/pdf/JBiogRimicaris2010.pdf','EPRINT'); return false;" href="http://www.ccmar.ualg.pt/maree/pdf/JBiogRimicaris2010.pdf"><span id="translatedtitle">Recent population expansion and connectivity in the <span class="hlt">hydrothermal</span> shrimp</span></a></p> <p><a target="_blank" href="http://www.osti.gov/eprints/">E-print Network</a></p> <p>Borges, Rita</p> <p></p> <p>-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are unstable habitats that are both spatially and temporally fragmented. In <span class="hlt">vent</span> species of the shrimp Rimicaris exoculata, which forms high-density local populations on <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> along the Mid-Atlantic ridge. Location Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> along the Mid-Atlantic Ridge. Methods We used</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRB..119.2543B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRB..119.2543B"><span id="translatedtitle">Temporal variability and tidal modulation of <span class="hlt">hydrothermal</span> exit-fluid temperatures at the Lucky Strike deep-sea <span class="hlt">vent</span> field, Mid-Atlantic Ridge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barreyre, Thibaut; Escartín, Javier; Sohn, Robert A.; Cannat, Mathilde; Ballu, Valérie; Crawford, Wayne C.</p> <p>2014-04-01</p> <p>We deployed autonomous temperature sensors at black smoker chimneys, cracks, and diffuse flow areas at the Lucky Strike <span class="hlt">hydrothermal</span> field (Mid-Atlantic Ridge, ~37°17'N) between summer 2009 and summer 2012 and contemporaneously measured tidal pressures and currents as part of the long-term MoMAR experiment to monitor <span class="hlt">hydrothermal</span> activity. We classify the temperature data according to the hydrogeologic setting of the measurement <span class="hlt">sites</span>: a high-temperature regime (>190°C) representing discharge of essentially unmixed, primary <span class="hlt">hydrothermal</span> fluids through chimneys, an intermediate-temperature regime (10-100°C) associated with mixing of primary fluids with cold pore fluids discharging through cracks, and a low-temperature regime (<10°C) associated with a thermal boundary layer forming over bacterial mats associated with diffuse outflow of warm fluids. Temperature records from all the regimes exhibit variations at semi-diurnal tidal periods, and cross-spectral analyses reveal that high-temperature discharge correlates to tidal pressure while low-temperature discharge correlates to tidal currents. Intermediate-temperature discharge exhibits a transitional behavior correlating to both tidal pressure and currents. Episodic perturbations, with transient temperature drops of up to ~150°C, which occur in the high-temperature and intermediate-temperature records, are not observed on multiple probes (including nearby probes at the same <span class="hlt">site</span>), and they are not correlated with microearthquake activity, indicating that the perturbation mechanism is highly localized at the measurement <span class="hlt">sites</span> within the <span class="hlt">hydrothermal</span> structures. The average temperature at a given <span class="hlt">site</span> may increase or decrease at annual time scales, but the average temperature of the <span class="hlt">hydrothermal</span> field, as a whole, appears to be stable over our 3 year observation period.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4136832','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4136832"><span id="translatedtitle">Physiological and Genomic Features of a Novel Sulfur-Oxidizing Gammaproteobacterium Belonging to a Previously Uncultivated Symbiotic Lineage Isolated from a <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Nunoura, Takuro; Takaki, Yoshihiro; Kazama, Hiromi; Kakuta, Jungo; Shimamura, Shigeru; Makita, Hiroko; Hirai, Miho; Miyazaki, Masayuki; Takai, Ken</p> <p>2014-01-01</p> <p>Strain Hiromi 1, a sulfur-oxidizing gammaproteobacterium was isolated from a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimney in the Okinawa Trough and represents a novel genus that may include a phylogenetic group found as endosymbionts of deep-sea gastropods. The SSU rRNA gene sequence similarity between strain Hiromi 1 and the gastropod endosymbionts was approximately 97%. The strain was shown to grow both chemolithoautotrophically and chemolithoheterotrophically with an energy metabolism of sulfur oxidation and O2 or nitrate reduction. Under chemolithoheterotrophic growth conditions, the strain utilized organic acids and proteinaceous compounds as the carbon and/or nitrogen sources but not the energy source. Various sugars did not support growth as a sole carbon source. The observation of chemolithoheterotrophy in this strain is in line with metagenomic analyses of endosymbionts suggesting the occurrence of chemolithoheterotrophy in gammaproteobacterial symbionts. Chemolithoheterotrophy and the presence of homologous genes for virulence- and quorum sensing-related functions suggest that the sulfur-oxidizing chomolithotrophic microbes seek animal bodies and microbial biofilm formation to obtain supplemental organic carbons in <span class="hlt">hydrothermal</span> ecosystems. PMID:25133584</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DSRII.111...76K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DSRII.111...76K"><span id="translatedtitle">Biogeography of deep-sea wood fall, cold seep and <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> Ostracoda (Crustacea), with the description of a new family and a taxonomic key to living Cytheroidea</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karanovic, Ivana; Brandão, Simone Nunes</p> <p>2015-01-01</p> <p>Stimulated by finding a novel cytheroid ostracod in a piece of sunken wood retrieved from the sea-bed in the Kuril-Kamchatka Trench, we have reviewed all previously published data on ostracods from similarly ephemeral deep-sea habitats (wood falls, <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> and cold seeps). These data are placed in the context of all data on living, deep-sea ostracods from other environments. We confirm previous authors' conclusions that faunas from these ephemeral habitats are similar at the generic level, and include elements common to shallow and deep habitats. However, at the species level, endemism varies from zero at cold seeps, to 35% in wood falls and 60% at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, which is an indication of the relative longevity of these habitats. Non-endemic species occur also in oligotrophic, deep-sea sediments but not in shallow environments. This is in contradiction to previous assumptions that these ephemeral faunas share more species and with shallow habitats than genera with the oligotrophic, deep-sea sediments. We agree with previous authors that the dispersal strategy of wood fall, <span class="hlt">vent</span> and seep ostracods includes hitchhiking and we propose that it also includes the ability to survive ingestion by larger, more motile animals. The homogeneity of the faunas from ephemeral habitats collected off the American continent is in stark contrast to the highly endemic fauna found in Northwestern Pacific. This suggests that the ostracods may have biogeographical patterns similar to those previously proposed for other groups of benthos. However, any proposal for a global biogeographical scheme for ostracod distributions will have to await far more comprehensive coverage from presently unstudied regions. Finally, we describe and name a novel species of ostracod from the wood fall collected at a depth of 5229 m in the abyss east to the Kuril-Kamchatka Trench, Northwestern Pacific; erecting a new family Keysercytheridae fam. nov. and a new genus, Keysercythere gen. nov., to accommodate it, and name it, Keysercythere enricoi sp. nov. We present a preliminary key to all Cytheroidea families for which living representatives have been described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2689276','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2689276"><span id="translatedtitle">Molecular identification of differentially regulated genes in the <span class="hlt">hydrothermal-vent</span> species Bathymodiolus thermophilus and Paralvinella pandorae in response to temperature</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Boutet, Isabelle; Jollivet, Didier; Shillito, Bruce; Moraga, Dario; Tanguy, Arnaud</p> <p>2009-01-01</p> <p>Background <span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> and cold seeps represent oases of life in the deep-sea environment, but are also characterized by challenging physical and chemical conditions. The effect of temperature fluctuations on <span class="hlt">vent</span> organisms in their habitat has not been well explored, in particular at a molecular level, most gene expression studies being conducted on coastal marine species. In order to better understand the response of <span class="hlt">hydrothermal</span> organisms to different temperature regimes, differentially expressed genes (obtained by a subtractive suppression hybridization approach) were identified in the mussel Bathymodiolus thermophilus and the annelid Paralvinella pandorae irlandei to characterize the physiological processes involved when animals are subjected to long term exposure (2 days) at two contrasting temperatures (10° versus 20°C), while maintained at in situ pressures. To avoid a potential effect of pressure, the experimental animals were initially thermally acclimated for 24 hours in a pressurized vessel. Results For each species, we produced two subtractive cDNA libraries (forward and reverse) from sets of deep-sea mussels and annelids exposed together to a thermal challenge under pressure. RNA extracted from the gills, adductor muscle, mantle and foot tissue were used for B. thermophilus. For the annelid model, whole animals (small individuals) were used. For each of the four libraries, we sequenced 200 clones, resulting in 78 and 83 unique sequences in mussels and annelids (about 20% of the sequencing effort), respectively, with only half of them corresponding to known genes. Real-time PCR was used to validate differentially expressed genes identified in the corresponding libraries. Strong expression variations have been observed for some specific genes such as the intracellular hemoglobin, the nidogen protein, and Rab7 in P. pandorae, and the SPARC protein, cyclophilin, foot protein and adhesive plaque protein in B. thermophilus. Conclusion Our results indicate that mussels and worms are not responding in the same way to temperature variations. While the results obtained for the mussel B. thermophilus seem to indicate a metabolic depression (strong decrease in the level of mRNA expression of numerous genes) when temperature increased, the annelid P. pandorae mainly displayed a strong regulation of the mRNA encoding subunits and linkers of respiratory pigments and some proteins involved in membrane structure. In both cases, these regulations seem to be partly due to a possible cellular oxidative stress induced by the simulated thermal environment (10°C to 20°C). This work will serve as a starting point for studying the transcriptomic response of <span class="hlt">hydrothermal</span> mussels and annelids in future experiments in response to thermal stress at various conditions of duration and temperature challenge. PMID:19439073</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.B14B..02D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.B14B..02D"><span id="translatedtitle">Culture-Independent Identification of Manganese-Oxidizing Genes from Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Chemoautotrophic Ferromanganese Microbial Communities Using a Metagenomic Approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Davis, R.; Tebo, B. M.</p> <p>2013-12-01</p> <p>Microbial activity has long been recognized as being important to the fate of manganese (Mn) in <span class="hlt">hydrothermal</span> systems, yet we know very little about the organisms that catalyze Mn oxidation, the mechanisms by which Mn is oxidized or the physiological function that Mn oxidation serves in these <span class="hlt">hydrothermal</span> systems. <span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> with thick ferromanganese microbial mats and Mn oxide-coated rocks observed throughout the Pacific Ring of Fire are ideal models to study the mechanisms of microbial Mn oxidation, as well as primary productivity in these metal-cycling ecosystems. We sampled ferromanganese microbial mats from Vai Lili <span class="hlt">Vent</span> Field (Tmax=43°C) located on the Eastern Lau Spreading Center and Mn oxide-encrusted rhyolytic pumice (4°C) from Niua South Seamount on the Tonga Volcanic Arc. Metagenomic libraries were constructed and assembled from these samples and key genes known to be in