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Sample records for hydrothermal vent site

  1. Hydrothermal Fluxes at the Turtle Pits Vent Site, southern MAR

    NASA Astrophysics Data System (ADS)

    Köhler, J.; Walter, M.; Mertens, C.; Sültenfuß, J.; Rhein, M.

    2009-04-01

    The Turtle Pits vent fields are located in a north-south orientated rift valley at the Mid-Atlantic Ridge (MAR) near 5oS. The site consists of three known hydrothermal fields: Turtle Pits, Comfortless Cove, and Red Lion. Data collected during a Meteor cruise in May 2006 and a L' Atalante cruise in January 2008 are used to calculate the total emission of volume, heat, and helium of the site. The data sets consist of vertical profiles and towed transsects of temperature, salinity, and turbidity, as well as direct velocity measurements with a lowered acoustic Doppler current profiler (LADCP) and water samples for Helium isotope analysis. Vent fluid samples for noble gas analysis where taken with an ROV. The particle plume is confined to the rift valley since the depth of the valley exceeds the rise height of the plume. Therefore the fluxes of heat and volume can be estimated from the helium fluxes at the vent sites in comparison with the horizontal helium transport in the valley. The comparison of the 3He concentration measured south of the hydrothermal vents with the 3He signal north of the hydrothermal vents suggests a rather strong northward flow. This is confirmed by the tide corrected velocities observed with the LADCP during the Meteor cruise. The northward volume transport has been calculated using the local bathymetry and tide corrected velocities from the Meteor cruise. In combination with the 3He concentrations and an average 3He end member concentration a flux of 900 l/s is estimated, which corresponds to a heat flux of 450 MW. The rise height of the particle plume estimated from the turbidity data combined with the known background stratification yields an estimate of the total flux of the hydrothermal vents which is one order of magnitude lower.

  2. Discovery of new hydrothermal vent sites in Bransfield Strait, Antarctica

    NASA Astrophysics Data System (ADS)

    Klinkhammer, G. P.; Chin, C. S.; Keller, R. A.; Dählmann, A.; Sahling, H.; Sarthou, G.; Petersen, S.; Smith, F.; Wilson, C.

    2001-12-01

    We carried out a search for hydrothermal vents in the Central Basin of Bransfield Strait, Antarctica. The ZAPS (zero angle photon spectrometer) chemical sensor and instrument package (Oregon State University), OFOS (ocean-floor observation system) camera sled and TVG (TV-grab) (GEOMAR) were used to explore the water column and underlying seafloor. These operations were supplemented with a series of dredges. Hydrothermal plumes over Hook Ridge at the eastern end of the basin are confined to the E ridge crest and SE flank. The plumes are complex and sometimes contain two turbidity maxima one widespread feature centered at 1150 m and a smaller, more localized but broad maximum at 600-800 m. We traced the source of the shallower plume to a sunken crater near the ridge crest using sensors on the ZAPS instrument package. Subsequently two TV-grabs from the crater brought back hot, soupy sediment (42-49°C) overlain by hard, siliceous crusts and underlain by a thick layer of volcanic ash. We also recovered chimney fragments whose texture and mineralogy indicate venting temperatures in excess of 250°C. Native sulfur and Fe-sulfides occur in fractures and porous layers in sediment from throughout the area. Pore water data from the crater site are consistent with venting into a thin sediment layer and indicate phase separation of fluids beneath Hook Ridge. The source of the deeper plumes at Hook Ridge has yet to be located. We also explored a series of three parallel volcanic ridges west of Hook Ridge called Three Sisters. We detected water column anomalies indicative of venting with the ZAPS package and recovered hydrothermal barites and sulfides from Middle Sister. We spent considerable time photographing Middle Sister and Hook Ridge but did not identify classic vent fauna at either location. We either missed small areas with our photography or typical MOR vent fauna are absent at these sites.

  3. Quantifying diffuse and discrete venting at the Tour Eiffel vent site, Lucky Strike hydrothermal field

    NASA Astrophysics Data System (ADS)

    Mittelstaedt, Eric; EscartíN, Javier; Gracias, Nuno; Olive, Jean-Arthur; Barreyre, Thibaut; Davaille, Anne; Cannat, Mathilde; Garcia, Rafael

    2012-04-01

    The relative heat carried by diffuse versus discrete venting of hydrothermal fluids at mid-ocean ridges is poorly constrained and likely varies among vent sites. Estimates of the proportion of heat carried by diffuse flow range from 0% to 100% of the total axial heat flux. Here, we present an approach that integrates imagery, video, and temperature measurements to accurately estimate this partitioning at a single vent site, Tour Eiffel in the Lucky Strike hydrothermal field along the Mid-Atlantic Ridge. Fluid temperatures, photographic mosaics of the vent site, and video sequences of fluid flow were acquired during the Bathyluck'09 cruise (Fall, 2009) and the Momarsat'10 cruise (Summer, 2010) to the Lucky Strike hydrothermal field by the ROV Victor6000 aboard the French research vessel the "Pourquoi Pas"? (IFREMER, France). We use two optical methods to calculate the velocities of imaged hydrothermal fluids: (1) for diffuse venting, Diffuse Flow Velocimetry tracks the displacement of refractive index anomalies through time, and (2) for discrete jets, Particle Image Velocimetry tracks eddies by cross-correlation of pixel intensities between subsequent images. To circumvent video blurring associated with rapid velocities at vent orifices, exit velocities at discrete vents are calculated from the best fit of the observed velocity field to a model of a steady state turbulent plume where we vary the model vent radius and fluid exit velocity. Our results yield vertical velocities of diffuse effluent between 0.9 cm s-1 and 11.1 cm s-1 for fluid temperatures between 3°C and 33.5°C above that of ambient seawater, and exit velocities of discrete jets between 22 cm s-1 and 119 cm s-1 for fluid temperatures between 200°C and 301°C above ambient seawater. Using the calculated fluid velocities, temperature measurements, and photo mosaics of the actively venting areas, we calculate a heat flux due to diffuse venting from thin fractures of 3.15 ± 2.22 MW, discrete venting of 1.07 ± 0.66 MW, and, by incorporating previous estimates of diffuse heat flux density from Tour Eiffel, diffuse flux from the main sulfide mound of ˜15.6 MW. We estimate that the total integrated heat flux from the Tour Eiffel site is 19.82 ± 2.88 MW and that the ratio of diffuse to discrete heat flux is ˜18. We discuss the implication of these results for the characterization of different vent sites within Lucky Strike and in the context of a compilation of all available measurements of the ratio of diffuse to discrete heat flux.

  4. Seismological evidence for an along-axis hydrothermal flow at the Lucky Strike hydrothermal vents site

    NASA Astrophysics Data System (ADS)

    Rai, A.; Wang, H.; Singh, S. C.; Crawford, W. C.; Escartin, J.; Cannat, M.

    2010-12-01

    Hydrothermal circulation at ocean spreading centres plays fundamental role in crustal accretion process, heat extraction from the earth and helps to maintain very rich ecosystem in deep Ocean. Recently, it has been suggested that hydrothermal circulation is mainly along the ridge axis at fast spreading centres above along axis melt lens (AMC). Using a combination of micro-earthquake and seismic reflection data, we show that the hydrothermal circulation at the Lucky Strike segment of slow spreading Mid-Atlantic Ridge is also along axis in a narrow (~1 km) zone above a wide (2-3 km) AMC. We find that the seismicity mainly lies above the seismically imaged 3 km wide 7 km long melt lens at 3.2 km depth. We observe a vertical plume of seismicity above a weak AMC reflection just north of the hydrothermal vent fields that initiates just above the AMC and continues to the seafloor. This zone is collocated with active rifting of the seafloor in the neo-volcanic zone. Beneath the hydrothermal vents sites, where a strong melt lens is imaged, the seismicity initiates at 500 m above the AMC and continues to the seafloor. Just south of the hydrothermal field, where the AMC is widest and strongest, the seismicity band lies 500 m above the melt lens in a 800 m thick zone, which does not continue to the seafloor. The presence the weak melt lens reflection could be due to a cooled and crystallised AMC (mush) that permits the penetration of hydrothermal fluids down to the top of the AMC indicated by seismicity plume and might be the in-flow zone for hydrothermal circulation. The strong AMC reflection could be due to fresh supply of melt in the AMC (pure melt), which has pushed the cracking front 500 m above the AMC. Beneath the hydrothermal fields, the strong AMC reflection and seismicity 500 above the AMC to the seafloor could represent cracking along the up-flow zone. The 800 m thick zone of seismicity above the pure melt zone could be the zone of hydrothermal cracking zone. We do not observe any seismicity along the main bounding faults. These results suggest that the hydrothermal flow is mainly along the ridge axis in a narrow zone above the AMC, even when the AMC only 7 km long.

  5. Controls of surface topography on submarine and subaerial hydrothermal fluid flow and vent-site location

    NASA Astrophysics Data System (ADS)

    Bani Hassan, N.; Rupke, L.; Iyer, K. H.; Borgia, A.

    2010-12-01

    Hydrothermal convection is an important process that occurs in the oceanic lithosphere as well as within continents where the geothermal gradient is high enough to drive fluid flow. This process efficiently mines heat from the lithosphere, sustains life in the otherwise bleak settings at oceanic depths and is associated with mineral deposits. Although recent focus on hydrothermal systems has greatly improved our understanding on how they work, the detailed effects of topography on these systems has largely been ignored. While the qualitative effects of topography on hydrothermal flow are largely known (e.g. Ingebritsen 2006), we here present results from systematic numerical modeling on the importance of topography for both, subaerial and submarine hydrothermal convection. The model is based on a 2-D Finite Element Method (FEM) solver for fully compressible, single-phase, porous media fluid flow and is used to simulate hydrothermal convection in a number of synthetic studies as well as for two case studies for the Lucky Strike vent field (submarine) and the Amiata volcano (subaerial). The results of synthetic studies using sinusoidal topography variations show that topography indeed has a profound effect on the distribution and flow field of the convection cells. In the submarine case, fluid venting occurs at the topographic highs while the recharge zones are restricted to the lows. For the subaerial scenarios, the opposite occurs where groundwater flow focuses venting at flank regions and the recharge zones are situated at the highs. For example, in the submarine case, ~90% of the hydrothermal fluids vent at upper 50% of topographic highs if the number of topographic highs equals the number of plumes in a flat-top reference simulation. The results show that the focusing effect into topographic highs (submarine) and lows (subaerial) is highly dependent on the wavelength and amplitude of topography, i.e. wavelengths that are too high or low result in venting at flanks or even topographic lows (submarine case). Amplitude also has a first-order effect of focusing the vent sites on topographic highs and lows. Another observation is that the wavelength of the topography affects the number of plumes generated in the model. These findings are confirmed in two case studies for the submarine Lucky Strike hydrothermal field on the Mid-Atlantic Ridge and the subaerial geothermal field of Amiata, Italy. In both case studies the predicted vent locations fit well with the observed ones.

  6. Discovery of New Hydrothermal Venting Sites in the Lau Basin, Tonga Back Arc

    NASA Astrophysics Data System (ADS)

    Crowhurst, P. V.; Arculus, R. J.; Massoth, G. J.; Baptista, L.; Stevenson, I.; Angus, R.; Baker, E. T.; Walker, S. L.; Nakamura, K.

    2009-12-01

    Between 22 April and 25 June 2009, a systematic search for hydrothermal venting along 1340 km of back-arc features was conducted throughout the Lau Basin aboard the CSIRO owned RV Southern Surveyor. The selection of survey areas was based on bathymetry, sidescan and water column anomaly datasets collected during previous marine science research and commercial exploration voyages. During 54 operational days, 76 CTD tows were completed using real-time plume mapping protocols, augmented with mini autonomous plume recorders, to discern anomalies in light scattering, and oxidation-reduction potential with water samples collected within the peak anomalies. Coincident with CTD towing at an average speed of 1.1 knots high resolution EM300 bathymetry and backscatter data was collected which significantly enhanced geological interpretation of possible source sites for follow up cross tows. 32 venting sites were detected, 24 of which are believed to be new discoveries. 13 dredge operations were conducted on 7 of these sites. Sulfides were recovered from 2 sites, one being a new discovery on the NE Lau spreading centre, ~14 km north of the commercial discovery by Teck and ~7km north of the eruption site discovery during a RV Thompson NOAA survey, both during 2008. The new venting field discoveries at North Mata, northern extent of the CLSC and far southern Valu Fa ridge are beyond any previously known areas of hydrothermal activity and further enhances the reputation of the Lau Basin as one of the most productive back arc regions for hydrothermally active spreading centers. A significant number of filter residue samples collected from the vent sites yielded greater than background values for metals including Cu and Zn, which is interpreted to imply they were sourced from active seafloor massive sulfide systems rather than volcanic activity.

  7. Food Web Structure at South Su, Solwara 1 and Solwara 8 Hydrothermal Vent Sites (Manus Basin)

    NASA Astrophysics Data System (ADS)

    Honig, D. L.; Hsing, P.; Jones, R.; Schultz, T.; Sobel, A.; Thaler, A.; van Dover, C. L.

    2008-12-01

    A robust understanding of food webs in chemoautotrophically based hydrothermal vent ecosystems requires quantifying the input of local bacterial chemoautoptrophic production vs. photosynthetically derived debris from surface waters. As an initial step towards this goal for vent communities in Papua New Guinea's Manus Basin, we use isotopic ratios of carbon, nitrogen and sulfur to describe trophic relations among 17 invertebrate genera collected in July 2008 at the Solwara 1, Solwara 8 and South Su hydrothermal vent beds. Prior stable isotope work by Erickson, Macko and Van Dover (unpublished) at Manus Basin vent sites suggests that we will see relatively depleted ä13C and ä15N values for the primary consumers Ifremeria, Alviniconcha and Olgasolaris compared to secondary consumers like the mobile, scavenging genera Munidopsis, Austinograea, Alvinocaris and Chorocaris, sessile suspension feeders of the genera Eochinolasmus and Vulcanolepas, and the predatory sponge Abyssocladia. We further hypothesize that mobile fauna will exhibit greater within-genus variance of ä13C, ä15N and ä34S values than sessile genera due to mobile organisms' ability to forage for photosynthetically derived detritus.

  8. 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.

  9. Hydrocarbons in surface sediments from a Guaymas Basin hydrothermal vent site. Technical report

    SciTech Connect

    Bazylinski, D.A.; Farrington, J.W.; Jannasch, H.W.

    1988-01-01

    Petroleum-like materials found at the Guaymas Basin hydrothermal vent site (Gulf of California) are derived from pyrolysis of organic matter. Two characteristics surface sediment cores differing in temperature profiles and other parameters were collected by DSV ALVIN, sectioned, and analyzed for hydrocarbons. The quantitative and qualitative composition of alkanes, steranes, diasteranes, and triterpanes differed between these cores as well as within sections of the same core. These differences, apparent for scales of tens of centimeters, are related to interactive physical, chemical, and microbial processes as well as the influence of multiple sources for the petroleum.

  10. Liquid Carbon Dioxide Venting at the Champagne Hydrothermal Site, NW Eifuku Volcano, Mariana Arc

    NASA Astrophysics Data System (ADS)

    Lupton, J.; Lilley, M.; Butterfield, D.; Evans, L.; Embley, R.; Olson, E.; Proskurowski, G.; Resing, J.; Roe, K.; Greene, R.; Lebon, G.

    2004-12-01

    In March/April 2004, submersible dives with the remotely-operated vehicle ROPOS discovered an unusual CO2-rich hydrothermal system near the summit of NW Eifuku, a submarine volcano located at 21.49° N, 144.04° E in the northern Mariana Arc. Although several sites of hydrothermal discharge were located on NW Eifuku, the most intense venting was found at 1600-m depth at the Champagne site, slightly west of the volcano summit. The Champagne site was found to be discharging two distinct fluids into the ocean: a) several small white chimneys were emitting milky 103° C gas-rich hydrothermal fluid with at least millimolar levels of H2S and b) cold (< 4° C) droplets coated with a milky skin were rising slowly from the sediment. These droplets were later determined to consist mainly of liquid CO2, with H2S as a probable secondary component. The droplets were sticky, and did not tend to coalesce into larger droplets, even though they adhered to the ROV like clumps of grapes. The film coating the droplets was assumed to be CO2 hydrate (or clathrate) which is known to form whenever liquid CO2 contacts water under these P,T conditions. Samples of the 103° C hydrothermal fluids were collected in special gas-tight titanium sampling bottles that were able to withstand the high internal pressures created by the dissolved gases. The Champagne hydrothermal fluids contained a surprising 2.3 moles/kg of CO2, an order of magnitude higher than any CO2 values previously reported for submarine hydrothermal fluids. The overall gas composition was 87% CO2, < 0.1% CH4, < 2 ppm H2, 0.012 mM/kg 4He, with the remaining 13% (322 mM/kg) assumed to be sulfur gases (H2S, SO2, etc.). (Additional analyses planned will confirm the speciation of this sulfur gas component). The helium had R/RA = 7.3, typical of subduction zone systems (R = 3He/4He and RA = Rair). Isotopic analysis of the CO2 yielded δ 13C = -1.75 ‰ , much heavier than the -6.0 ‰ typical for carbon in MOR vent fluids. The C/3He ratio was ~2.2 x 1010, an order of magnitude higher than the average value of 2 x 109 found in MOR vent fluids. The δ 13C and C/3He values suggest a substantial contribution to the carbon from subducted carbonates rather than mantle carbon. The Champagne site is only the second locality where liquid CO2 has been observed venting into the deep sea (the other reported location is in the Okinawa Trough, see Sakai et al., 1990). Because of the presence of liquid CO2 in proximity to hydrothermal organisms, the Champagne site may prove to be a valuable natural laboratory for studying the effects of high CO2 concentrations on marine ecosystems.

  11. Microbial utilization of naturally occurring hydrocarbons at the Guaymas Basin hydrothermal vent site

    SciTech Connect

    Bazylinski, D.A.; Wirsen, C.O.; Jannasch, H.W. )

    1989-11-01

    The Guaymas Basin (Gulf of California; depth, 2,000 m) is a site of hydrothermal activity in which petroliferous materials is formed by thermal alteration of deposited planktonic and terrestrial organic matter. We investigated certain components of these naturally occurring hydrocarbons as potential carbon sources for a specific microflora at these deep-sea vent sites. Respiratory conversion of (1-{sup 14}C)hexadecane and (1(4,5,8)-{sup 14}C)naphthalene to {sup 14}CO{sub 2} was observed at 4{degree}C and 25{degree}C, and some was observed at 55{degree}C, but none was observed at 80{degree}C. Bacterial isolates were capable of growing on both substrates as the sole carbon source. All isolates were aerobic and mesophilic with respect to growth on hydrocarbons but also grew at low temperatures (4 to 5{degree}C). These results correlate well with previous geochemical analyses, indicating microbial hydrocarbon degradation, and show that at least some of the thermally produced hydrocarbons at Guaymas Basin are significant carbon sources to vent microbiota.

  12. 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 μm to ~1000 μm 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.

  13. Biogeography of bacteriophages at four hydrothermal vent sites in the Antarctic based on g23 sequence diversity.

    PubMed

    Millard, Andrew D; Pearce, David; Zwirglmaier, Katrin

    2016-04-01

    In this study, which was carried out within the ChEsSO consortium project (Chemosynthetically driven ecosystems south of the Polar Front), we sampled two hydrothermal vent sites on the East Scotia Ridge, Scotia Sea, one in the Kemp Caldera, South Sandwich Arc and one in the Bransfield Strait, north-west of the Antarctic Peninsula, which exhibit strong differences in their chemical characteristics. We compared a subset of their bacteriophage population by Sanger- and 454-sequencing of g23, which codes for the major capsid protein of T4likeviruses. We found that the sites differ vastly in their bacteriophage diversity, which reflects the differences in the chemical conditions and therefore putatively the differences in microbial hosts living at these sites. Comparing phage diversity in the vent samples to other aquatic samples, the vent samples formed a distinct separate cluster, which also included the non-vent control samples that were taken several hundred meters above the vent chimneys. This indicates that the influence of the vents on the microbial population and therefore also the bacteriophage population extends much further than anticipated. PMID:26903011

  14. 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-κB, 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

  15. Acoustic mapping of diffuse flow at a seafloor hydrothermal site: Monolith Vent, Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Rona, P. A.; Jackson, D. R.; Wen, T.; Jones, C.; Mitsuzawa, K.; Bemis, K. G.; Dworski, J. G.

    Diffuse flow of hydrothermal solutions commonly occurs in patchy areas up to tens of meters in diameter in seafloor hydrothermal fields. It is recognized as a quantitatively significant component of thermal and chemical fluxes, yet is elusive to map. We report a new acoustic method to detect and map areas of diffuse flow using phase-coherent correlation techniques. The sonar system was modified to record phase information and mounted on DSV SEA CLIFF. The submersible occupied a stationary position on the seafloor and the transducer scanned the seafloor surrounding Monolith Vent, a sulfide edifice venting black smokers, at a nominal range of 17 m at a depth of 2249 m on the Juan de Fuca Ridge. Patchy areas of uncorrelated returns clearly stood out from a background of returns that exhibited ping-to-ping correlation. The areas of uncorrelated returns coincided with areas of diffuse flow as mapped by a video survey with the Navy's Advanced Tethered Vehicle (ATV). Correlated returns were backscattered from invariant seafloor. Uncorrelated returns were distorted by index of refraction inhomogeneities as they passed through diffuse flow between the seafloor and the transducer. The acoustic method presented can synoptically map areas of diffuse flow. When combined with standard in situ measurement and sampling methods the acoustic mapping will facilitate accurate determination of diffuse thermal and chemical fluxes in seafloor hydrothermal fields.

  16. Mantle to hydrothermal vent sites of the Southern Mariana Trough back-arc Basin: Results from the Taiga Project

    NASA Astrophysics Data System (ADS)

    Seama, N.; Okino, K.; Nogi, Y.; Sato, T.; Matsuno, T.; Yoshikawa, S.; Mochizuki, N.; Shinohara, M.

    2012-12-01

    The southern Mariana Trough back-arc basin shows an EPR type axial relief in morphology and constant low mantle Bouguer anomaly along the spreading axis (Kitada et al., 2006), suggesting abundance of magma supply, even though the full spreading rate of 40 km/Myr is categorized as slow spreading. Further, five hydrothermal vent sites exist within 5 km near the spreading axis at 13 N; two sites on the spreading axis, one site at the eastern foot of the axial high, and two sites on an off-axis knoll. We selected this area as one of three integrated target sites for the Taiga Project, and we conducted series of JAMSTEC research cruises for four different types of geophysical surveys, together with dive observation and samplings by the submersible Shinkai6500. The geophysical surveys consists of 1) a marine magnetotelluric (MT) survey of a 130 km length transect across the spreading axis using 10 ocean bottom electro-magnetometers, 2) a 15 km scale seismic reflection/refraction survey and seismicity observation using 9 ocean bottom seismometers (OBS), 3) near-bottom acoustic and magnetic mapping around all the hydrothermal sites using the AUV Urashima, and 4) a magnetometric resistivity (MMR) survey around the on-axis hydrothermal sites. Two-dimensional electrical resistivity structure of the upper mantle from the MT analysis shows highly asymmetry, which may be affected by hydration driven by water release from the subducting slab; that may result in abundant magma supply to support EPR type axial morphology. Three months OBS observation shows that the seismicity near the hydrothermal vent sites is very low, suggesting that hydrothermal activities are not related to tectonic stress. Moreover, the morphology of the mound and knoll near the three off-axis hydrothermal sites shows undeformed features without any faults, suggesting that their formation is closely related to an off-axis magma upwelling system rather than fault systems. The two on-axis hydrothermal sites (the Yamanaka and Snail sites) are located near the end of a 4th order spreading segment based on the observed offset of the neo-volcanic zone, suggesting that they are possibly locally developed in association with diking events in the segment. But the diking is probably an episodic event to provide heat source for each hydrothermal site, because of very low seismicity. Clear magnetization low at four hydrothermal vent sites except the Yamanaka site suggests that the hydrothermal activities have continued for long enough periods in wide enough areas to reduce the magnetic remanence of the crustal rocks. The different feature in the Yamanaka site suggests its activity has been short and/or small. The MMR results support this difference because low electrical resistivity region with 200 meter scale is located only at the Snail site but not at the Yamanaka site; the low resistivity region is probably due to the existence of hot crustal pore fluid.

  17. 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

  18. Post-drilling hydrothermal vent and associated biological activities seen through artificial hydrothermal vents in the Iheya North field, Okinawa Trough

    NASA Astrophysics Data System (ADS)

    Takai, K.; Kawagucci, S.; Miyazaki, J.; Watsuji, T.; Ishibashi, J.; Yamamoto, H.; Nozaki, T.; Kashiwabara, T.; Shibuya, T.

    2012-12-01

    In 2010, IODP Expedition 331 was conducted in the Iheya North Field, the Okinawa Trough and drilled several sites in hydrothermally active subseafloor. In addition, during the IODP Expedition 331, four new hydrothermal vents were created. These post-drilling artificial hydrothermal vents provide excellent opportunities to investigate the physical, chemical and microbiological characteristics of the previously unexplored subseafloor hydrothermal fluid reservoirs, and to monitor and estimate how the anthropogenic drilling behaviors affect the deep-sea hydrothermal vent ecosystem. We were very much interested in the difference of hydrothermal fluid chemistry between the natural hydrothermal vents and the artificial hydrothermal vents. The IODP porewater chemistry of the cores pointed to the density-driven stratification of the phase-separated hydrothermal fluids and the natural vent fluids were likely derived only from the shallower vapor-enriched phases. However, the artificial hydrothermal vents had deeper fluid sources in the subseafloor hydrothermal fluid reservoirs composed of vapor-lost (Cl-enriched) phases. The fluids from the artificial hydrothermal vents were sampled by ROV at 5, 12 and 18 months after the IODP expedition. The artificial hydrothermal vent fluids were slightly enriched with Cl as compared to the natural hydrothermal vent fluids. Thus, the artificial hydrothermal vents successfully entrained the previously unexplored subseafloor hydrothermal fluids. The newly created hydrothermal vents also hosted the very quickly grown, enormous chimney structures, of which mineral compositions were highly variable among the vents. However, the quickly grown C0016B and C0016D vent chimneys were found to be typical Kuroko ore even though the chimney growth rates in the artificial vents were extremely faster than those in the natural vents. In addition, the IODP drilling operation not only created new hydrothermal vents by deep drilling but also induced the newly generated diffusing flows by many short drillings in the seafloor where no apparent hydrothermal fluid discharge was observed (e.g., C0013 and C0014). The new widespread diffusing flows altered the habitat condition, and provided post-drilling propagation and colonization of indigenous hydrothermal chemosynthetic animals. Interestingly, the first colonizers were shrimps and polychaeta, which were identified at C0013 and C0016 in 6 months after the IODP expedition, while the most drastic propagation and colonization were conducted by the most predominant chemosynthetic animal species in the Iheya North field, vent crab Shinkaia crosnieri. It appeared at C0014 site (500 m distant from their large colonies) in a year and dominated the new diffusing flow sites. It seems likely that IODP drilling operation and the post-drilling hydrothermal activities would have an impact on increasing biomass production and widespread propagation of hydrothermal vent ecosystem in the Iheya North field.

  19. 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

  20. Bacteria dominate the ammonia-oxidizing community in a hydrothermal vent site at the Mid-Atlantic Ridge of the South Atlantic Ocean.

    PubMed

    Xu, Wei; Li, Meng; Ding, Jie-Fei; Gu, Ji-Dong; Luo, Zhu-Hua

    2014-09-01

    Ammonia oxidation is the first and rate-limiting step of nitrification, which is carried out by two groups of microorganisms: ammonia-oxidizing bacteria (AOB) and the recently discovered ammonia-oxidizing archaea (AOA). In this study, diversity and abundance of AOB and AOA were investigated in five rock samples from a deep-sea hydrothermal vent site at the Mid-Atlantic Ridge (MAR) of the South Atlantic Ocean. Both bacterial and archaeal ammonia monooxygenase subunit A (amoA) gene sequences obtained in this study were closely related to the sequences retrieved from deep-sea environments, indicating that AOB and AOA in this hydrothermal vent site showed typical deep ocean features. AOA were more diverse but less abundant than AOB. The ratios of AOA/AOB amoA gene abundance ranged from 1/3893 to 1/242 in all investigate samples, indicating that bacteria may be the major members responding to the aerobic ammonia oxidation in this hydrothermal vent site. Furthermore, diversity and abundance of AOA and AOB were significantly correlated with the contents of total nitrogen and total sulfur in investigated samples, suggesting that these two environmental factors exert strong influences on distribution of ammonia oxidizers in deep-sea hydrothermal vent environment. PMID:24893665

  1. 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 μM (background = 43.2 ± 0.7 μM (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 μM, 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 μM 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://adsabs.harvard.edu/abs/1996GeoRL..23.2049V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996GeoRL..23.2049V"><span id="translatedtitle">Light 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>Van Dover, Cindy Lee; Reynolds, George T.; Chave, Alan D.; Tyson, J. Anthony</p> <p></p> <p>Ambient light spectral data were acquired at two deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> with a temperature of ˜350°C: the Hole-to-Hell <span class="hlt">site</span> on the East Pacific Rise at 9°N and the Snake-Pit <span class="hlt">site</span> on the Mid-Atlantic Ridge. Measurements were made with a simple, multi-channel photometer which simultaneously detected light in four 100 nm-wide bands over the wavelength range of 650-1050 nm. Most of the light detected is near-infrared (750-1050 nm), but there is a 19x greater photon flux than expected from thermal radiation alone at shorter wavelengths (650-750 nm) at the Hole-to-Hell <span class="hlt">vent</span>. At Snake Pit, more light in the 750-850 nm band was observed 10 cm above the orifice where the temperature was 50-100°C than at the 351°C <span class="hlt">vent</span> opening. These data suggest the presence of non-thermal light sources in the <span class="hlt">vent</span> environment. Some possible non-thermal mechanisms are identified, but further data will be required to resolve them.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24882018','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24882018"><span id="translatedtitle"><span class="hlt">Site</span>-related differences in gene expression and bacterial densities 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://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bettencourt, Raul; Rodrigues, Mónica; Barros, Inês; Cerqueira, Teresa; Freitas, Cátia; Costa, Valentina; Pinheiro, Miguel; Egas, Conceição; Santos, Ricardo Serrão</p> <p>2014-08-01</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">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> and in close vicinity of the Azores region near the Mid-Atlantic Ridge (MAR). The physiological relationships that <span class="hlt">vent</span> mussels have developed with their physical and chemical environments are likely to influence global gene expression profiles providing thus the means to investigate distinct biological markers predicting the origin of Bathymodiolus sp. irrespectively of their geographical localization. Differences found at gene expression levels, and between fluorescence in situ hybridization (FISH) and 16S rRNA amplicon sequencing results provided experimental evidence for the distinction of both Menez Gwen and Lucky Strike <span class="hlt">vent</span> mussel individuals based on bacterial and <span class="hlt">vent</span> mussel gene expression signatures and on the constitutive distribution and relative abundance of endosymbiotic bacteria within gill tissues. Our results confirmed the presence of methanotroph 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 a sulfur-oxidizing-related probe. Quantitative PCR (qPCR) studies revealed different 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 Menez Gwen or Lucky Strike animals whereas the genes encoding effector molecules appeared to have higher levels expression in gill tissues from Menez Gwen animals. The peptidoglycan recognition molecule encoding gene, PGRP, presented the highest level of transcriptional activity among the genes analyzed in Menez Gwen mussel 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 Menez Gwen and Lucky Strike mussel gill tissues. Remarkably, the immunity-related GTPase encoding gene demonstrated, in Lucky Strike samples, the highest level of expression among the signaling molecule encoding genes tested when expressions levels were compared between Menez Gwen and Lucky Strike animals. A differential expression analysis of bacterial genes between Menez Gwen and Lucky Strike mussels indicated a clear expression signature in the latter animal gill tissues. The bacterial community structure ensued from the 16S rRNA sequencing analyses pointed at an unpredicted conservation of endosymbiont bacterial loads between Menez Gwen and Lucky Strike samples. Taken together, our results support the hypothesis that B. azoricus exhibits different transcriptional statuses while living in distinct <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> may result in distinct gene expressions because of physico-chemical and/or symbiont densities differences. PMID:24882018</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://files.eric.ed.gov/fulltext/ED477324.pdf','ERIC'); return false;" href="http://files.eric.ed.gov/fulltext/ED477324.pdf"><span id="translatedtitle">Living with the Heat. Submarine Ring of Fire--Grades 5-6. <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Ecology.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>National Oceanic and Atmospheric Administration (DOC), Rockville, MD.</p> <p></p> <p>This activity is designed to teach about <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecology. Students are expected to describe how <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are formed and characterize the physical conditions at these <span class="hlt">sites</span>, explain chemosynthesis and contrast this process with photosynthesis, identify autotrophic bacteria as the basis for food webs in <span class="hlt">hydrothermal</span> vent…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.V41B2076G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.V41B2076G"><span id="translatedtitle">Bacterial Diets of Primary Consumers 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>Govenar, B.; Shank, T. M.</p> <p>2008-12-01</p> <p>Chemical energy produced by mixing <span class="hlt">hydrothermal</span> fluids and seawater supports dense biological communities on mid-ocean ridges. The base of the food web at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> is formed by chemolithoautotrophic bacteria that use the energy from the oxidation of reduced chemicals to fix inorganic carbon into simple sugars. With the exception of a few species that have chemolithoautotropic bacterial symbionts, most of the <span class="hlt">vent</span>-endemic macrofauna are heterotrophs that feed on free-living bacteria, protists, and other invertebrates. The most abundant and diverse group of primary consumers in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> communities belong to the Gastropoda, particularly the patellomorph limpets. Gastropod densities can be as high as 2000 individuals m-2, and there can be as many as 13 species of gastropods in a single aggregation of the siboglinid tubeworm Riftia pachyptila and more than 40 species along the East Pacific Rise. Some gastropods are ubiquitous and others are found in specific microhabitats, stages of succession, or associated with different foundation species. To determine the mechanisms of species coexistence (e.g. resource partitioning or competition) among <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> primary consumers and to track the flow of energy in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> communities, we employed molecular genetic techniques to identify the gut contents of four species of co-occurring <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> gastropods, Eulepetopsis vitrea, Lepetodrilus elevatus, Lepetodrilus ovalis and Lepetodrilus pustulosus, collected from a single diffuse-flow <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">site</span> on the East Pacific Rise. Unique haplotypes of the 16S gene that fell among the epsilon-proteobacteria were found in the guts of every species, and two species had gut contents that were similar only to epsilon-proteobacteria. Two species had gut contents that also included haplotypes that clustered with delta-proteobacteria, and one species had gut contents that clustered with alpha- proteobacteria. Differences in the diets of these four <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> gastropods may reflect microhabitat conditions where these species typically occur or where they were located at the time of the collection. Results from this work provide insights to the "bottom-up" regulation of primary consumers and tracking chemical fluxes through biological communities 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/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.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.ncbi.nlm.nih.gov/pubmed/22235192','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22235192"><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=pubmed">PubMed</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://adsabs.harvard.edu/abs/2006AGUFMOS34A..03S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFMOS34A..03S"><span id="translatedtitle">High-Temperature <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Field of Kolumbo Submarine Volcano, Aegean Sea: <span class="hlt">Site</span> of Active Kuroko-Type Mineralization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sigurdsson, H.; Carey, S.; Alexandri, M.; Vougioukalakis, G.; Croff, K.; Roman, C.; Sakellariou, D.; Anagnostou, C.; Rousakis, G.; Ioakim, C.; Gogou, A.; Ballas, D.; Misaridis, T.; Nomikou, P.</p> <p>2006-12-01</p> <p>Kolumbo submarine volcano is located 7 km north-east of the island of Santorini in the Hellenic arc (Greece), and comprises one of about twenty submarine cones in a NE-trending rift zone. Kolumbo erupted explosively in 1649-50AD, causing 70 fatalities on Santorini. Kolumbo's crater is 1700 m in diameter, with a crater rim at 10 m below sea level and crater floor at depth of 505 m. Recent marine geological investigations, using ROVs, reveal a very active high-temperature <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field in the northeastern part of the Kolumbo crater floor, about 25,000 m2. <span class="hlt">Vent</span> chimneys up to 4 m high are vigorously emitting colorless gas plumes up to 10 m high in the water column. Temperatures up to 220oC are recorded in <span class="hlt">vent</span> fluids. Some <span class="hlt">vents</span> are in crater- like depressions, containing debris from collapsed extinct chimneys. The entire crater floor of Kolumbo is mantled by a reddish-orange bacterial mat, and bacterial filaments of a variety of colors cling to chimneys in dense clusters. Glassy tunicates and anemones are common in lower-temperature environments on the crater floor. Most chimneys show a high porosity, with a central conduit surrounded by an open and very permeable framework of sulfides and sulfates, aiding fluid flow through the chimney walls. In the sulfate-rich samples, blades of euhedral barite and anhydrite crystals coat the outside of the chimney wall, and layers of barite alternate with sulfide in the interior. The dominant sulfides are pyrite, sphalerite, wurtzite, marcasite and galena. Crusts on extinct and lower-temperature chimneys are composed of amorphous silica, goethite and halite. Sulfur isotope composition of sulfates is virtually at sea water values, whereas the sulfides are more depleted. Elevated levels of copper, gold and silver are observed in bulk composition of chimney samples. Both the structural setting, character of the <span class="hlt">vent</span> field and sulfide/sulfate mineralogy and geochemistry indicate on-going Kuroko-type mineralization in the Kolumbo submarine crater today.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMNS33A..02N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMNS33A..02N"><span id="translatedtitle">Evidence for <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> as "Biogeobatteries" (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nielsen, M. E.; Girguis, P. R.</p> <p>2010-12-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> are unique systems that play an important role in oceanic biogeochemical cycles. As chemically reduced <span class="hlt">hydrothermal</span> fluid mixes with cold oxic seawater, minerals precipitate out of solution resulting in chimney structures composed largely of metal sulfides and anhydrite. Pyrite, which is a natural semi-conductor, is the primary sulfide mineral, but other minerals within chimneys are also conductive (e.g. chalcopyrite, wurtzite, and some iron oxides). Sulfide chimneys are also known to host an extensive endolithic microbial community. Accordingly, submarine <span class="hlt">hydrothermal</span> systems appear to be examples of biogeobatteries, wherein conductive mineral assemblages span naturally occuring redox gradients and enable anaerobic microbes to access oxygen as an oxidant via extracellular electron transfer (or EET). To test this hypothesis, we ran a series of electrochemical laboratory experiments in which pyrite was used as an anode (in a vessel flushed with <span class="hlt">hydrothermal</span>-like fluid). When placed in continuity with a carbon fiber cathode, pyrite was found to accept and conduct electrons from both abiotic and biological processes (microbial EET). Specifically, electrical current increased 4-fold (5 nA/m2 to 20 nA/m2) in response to inoculation with a slurry prepared from a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> sample. Inspection of the pyrite anode with SEM revealed ubiquitous coverage by microbes. DNA was extracted from the anodes and the inoculum, and was subjected to pyrosequencing to examine prokaryotic diversity. These data suggest that key microbial phylotypes were enriched upon the pyrite, implicating them in EET. In addition, we deployed an in situ experiment based on microbial fuel cell architecture with a graphite anode inserted into a <span class="hlt">vent</span> wall coupled to a carbon fiber cathode outside the <span class="hlt">vent</span>. We observed current production over the course of one year, implying microbial EET in situ. Via pyrosequencing, we observed that the microbial community on the anode was significantly enriched in gammaproteobacteria (with respect to the community on an inert substrate deployed in the same <span class="hlt">vent</span>, which was dominated by epsilonproteobacteria). The observation of electrical current and the enrichment of distinct microbial communities in both laboratory and in situ experiments provide evidence that <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> enable microbes capable of EET to access molecular oxygen in the surrounding seawater as an oxidant. This geochemical and microbial phenomenon may influence the chemistry and mineralogy of <span class="hlt">vent</span> systems, resulting in localized variations in pH that can influence metal mobilization on a global scale.</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://adsabs.harvard.edu/abs/1998DSRII..45..319V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998DSRII..45..319V"><span id="translatedtitle">Naked in toxic fluids: A nudibranch mollusc from <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>Valdés, Ángel; Bouchet, Philippe</p> <p>1998-01-01</p> <p>A new species of the nudibranch genus Dendronotus (Mollusca, Opisthobranchia) is reported from a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> at the Lucky Strike area, on the Mid-Atlantic Ridge. This is the first species of nudibranch recorded with certainty from a <span class="hlt">vent</span> <span class="hlt">site</span>. Other species of Dendronotus are distributed in temperate waters on the continental shelf of the northern hemisphere. Two factors that probably account for the occurrence of a nudibranch in this <span class="hlt">hydrothermal</span> field are that the Lucky Strike area presents potential hydroid prey, and that nudibranchs apparently inhabit a lower activity area. It is hypothesized that the new species, which lacks eyes, is a permanent resident of <span class="hlt">vent</span> fields on the Mid-Atlantic Ridge, but is probably not restricted to that environment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040065937&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dhydrothermal','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040065937&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dhydrothermal"><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://www.ncbi.nlm.nih.gov/pubmed/26913091','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26913091"><span id="translatedtitle">Isolation and complete genome sequence of the thermophilic Geobacillus sp. 12AMOR1 from an Arctic deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">site</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wissuwa, Juliane; Stokke, Runar; Fedøy, Anita-Elin; Lian, Kjersti; Smalås, Arne Oskar; Steen, Ida Helene</p> <p>2016-01-01</p> <p>Members of the genus Geobacillus have been isolated from a wide variety of habitats worldwide and are the subject for targeted enzyme utilization in various industrial applications. Here we report the isolation and complete genome sequence of the thermophilic starch-degrading Geobacillus sp. 12AMOR1. The strain 12AMOR1 was isolated from deep-sea hot sediment at the Jan Mayen <span class="hlt">hydrothermal</span> <span class="hlt">Vent</span> <span class="hlt">Site</span>. Geobacillus sp. 12AMOR1 consists of a 3,410,035 bp circular chromosome and a 32,689 bp plasmid with a G + C content of 52 % and 47 %, respectively. The genome comprises 3323 protein-coding genes, 88 tRNA species and 10 rRNA operons. The isolate grows on a suite of sugars, complex polysaccharides and proteinous carbon sources. Accordingly, a versatility of genes encoding carbohydrate-active enzymes (CAZy) and peptidases were identified in the genome. Expression, purification and characterization of an enzyme of the glycoside hydrolase family 13 revealed a starch-degrading capacity and high thermal stability with a melting temperature of 76.4 °C. Altogether, the data obtained point to a new isolate from a marine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> with a large bioprospecting potential. PMID:26913091</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.3504M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.3504M"><span id="translatedtitle">The use of photo-mosaics, bathymetry and sensor data into geographic information system for <span class="hlt">site</span> description and faunal distribution analysis at the Menez Gwen <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>Marcon, Y.; Sahling, H.; Bohrmann, G.</p> <p>2012-04-01</p> <p>The Menez Gwen <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> is located on the Mid-Atlantic Ridge at a depth of about 800m. Although it has been the focus of several expeditions and studies, the <span class="hlt">sites</span> of active <span class="hlt">venting</span> at Menez Gwen are still under described, and it is not possible to get a global picture of the <span class="hlt">sites</span> from the published data. Exploration of deep-sea environments is commonly performed using remotely operated vehicles (ROV) equipped with sensors, cameras and powerful lights. But strong attenuation of light in the deep-sea constrains visual surveys to be carried out from a few meters only above the seafloor, thus limiting the extent of the field of view. Moreover, ROV-mounted positioning systems usually lack accuracy and cannot be relied on for accurate relative positioning of sensor measurements, samplings, and features of interest. Such limitations are hindrances for many applications. In particular, <span class="hlt">site</span> description or mapping of deep-sea benthic fauna over an area of study usually requires lengthy surveys, and reliability of navigation data becomes a major issue. Also, studying small-scale spatial variations of a physicochemical parameter needs positions of sensor measurements or samplings to be known precisely. To overcome this problem, maps of the seafloor can be generated in the form of geo-referenced video- or photo-mosaics. Mosaics are constructed by assembling overlapping images together into a larger image of the scene. To reduce the effects of drift in the navigation data, the construction of the mosaics uses robust feature detection and mapping capabilities to precisely relate consecutive images together. After geo-referencing in a Geographic Information System (GIS), points of measurements and sampling can be accurately pinpointed onto the mosaics to allow for spatial analyses. During cruise M82/3 to the Menez Gwen <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> system, high-resolution photo-mosaics of several <span class="hlt">sites</span> of <span class="hlt">hydrothermal</span> activity were constructed and geo-referenced into GIS systems. The mosaics, together with high-resolution ship-borne bathymetry, allowed unravelling the layout and morphology of the system at different scales. Through GIS analyses, the distribution of the faunal communities in relation to the fluid emission points was mapped and sensor data were integrated to allow describing the spatial variation of water temperature based on CTD measurements. Results include calculation of mussel beds surfaces and inferred estimates of biomass of Bathymodiolus azoricus. Acknowledgements: This work is supported by the European Commission under the EU Framework 7 funded Marie Curie Initial Training Network (ITN) SENSEnet (contract n°237868), and funded through DFG Research Center / Excellence Cluster "The Ocean in the Earth System".</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://www.ncbi.nlm.nih.gov/pubmed/24924809','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24924809"><span id="translatedtitle">Using in situ voltammetry as a tool to identify and characterize habitats of iron-oxidizing bacteria: from fresh water wetlands to <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>MacDonald, Daniel J; Findlay, Alyssa J; McAllister, Sean M; Barnett, Josh M; Hredzak-Showalter, Patricia; Krepski, Sean T; Cone, Shane G; Scott, Jarrod; Bennett, Sarah K; Chan, Clara S; Emerson, David; Luther Iii, George W</p> <p>2014-09-20</p> <p>Iron-oxidizing bacteria (FeOB) likely play a large role in the biogeochemistry of iron, making the detection and understanding of the biogeochemical processes FeOB are involved in of critical importance. By deploying our in situ voltammetry system, we are able to measure a variety of redox species, specifically Fe(ii) and O2, simultaneously. This technique provides significant advantages in both characterizing the environments in which microaerophilic FeOB are found, and finding diverse conditions in which FeOB could potentially thrive. Described here are four environments with different salinities [one fresh groundwater seep <span class="hlt">site</span>, one beach-groundwater mixing <span class="hlt">site</span>, one <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">site</span> (Mid-Atlantic Ridge), and one estuary (Chesapeake Bay)] where in situ voltammetry was deployed, and where the presence of FeOB were confirmed by either culturing methods or molecular data. The <span class="hlt">sites</span> varied in both O2 and Fe(ii) content with O2 ranging from below the 3 μM detection limit of the electrodes at the Chesapeake Bay suboxic zone, to as high 150 μM O2 at the <span class="hlt">vent</span> <span class="hlt">site</span>. In addition, a range of Fe(ii) concentrations supported FeOB communities, from 3 μM Fe(ii) in the Chesapeake Bay to 300 μM in the beach aquifer. In situ electrochemistry provides the means to quickly measure these redox gradients at appropriate resolution, making it possible in real time to detect niches likely inhabited by microaerophilic FeOB, then accurately sample for proof of FeOB presence and activity. This study demonstrates the utility of this approach while also greatly expanding our knowledge of FeOB habitats. PMID:24924809</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21314717','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21314717"><span id="translatedtitle">Scientists as stakeholders in conservation of <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>Godet, Laurent; Zelnio, Kevin A; VAN Dover, Cindy L</p> <p>2011-04-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> are deep-sea ecosystems that are almost exclusively known and explored by scientists rather than the general public. Continuing scientific discoveries arising from study of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are concommitant with the increased number of scientific cruises visiting and sampling <span class="hlt">vent</span> ecosystems. Through a bibliometric analysis, we assessed the scientific value of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> relative to two of the most well-studied marine ecosystems, coral reefs and seagrass beds. Scientific literature on <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> is abundant, of high impact, international, and interdisciplinary and is comparable in these regards with literature on coral reefs and seagrass beds. Scientists may affect <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> because their activities are intense and spatially and temporally concentrated in these small systems. The potential for undesirable effects from scientific enterprise motivated the creation of a code of conduct for environmentally and scientifically benign use of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> for research. We surveyed scientists worldwide engaged in deep-sea research and found that scientists were aware of the code of conduct and thought it was relevant to conservation, but they did not feel informed or confident about the respect other researchers have for the code. Although this code may serve as a reminder of scientists' environmental responsibilities, conservation of particular <span class="hlt">vents</span> (e.g., closures to human activity, specific human management) may effectively ensure sustainable use of <span class="hlt">vent</span> ecosystems for all stakeholders. PMID:21314717</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://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://www.ncbi.nlm.nih.gov/pubmed/17841485','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17841485"><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://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jannasch, H W; Mottl, M J</p> <p>1985-08-23</p> <p>During the cycling of seawater through the earth's crust along the mid-ocean 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 ( approximately 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. PMID:17841485</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://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.osti.gov/scitech/biblio/6191629','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6191629"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> clam and tube worm /sup 13/C//sup 12/C: further evidence of nonphotosynthetic food sources</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Rau, G.H.</p> <p>1981-07-17</p> <p>The stable carbon isotope ratios in clam mantle tissues taken from both Galapagos and 21/sup 0/N <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> were similar to the unusually low ratios of carbon-13 to carbon-12 previously reported for a Galapagos <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel. In marked contrast to these bivalues, vestimentiferan worm tissues from a Galapagos <span class="hlt">vent</span> had isotope ratios that were higher than those of open ocean biota. These observations suggest that more than one nonpelagic and nonphotosynthetic carbon fixation pathway is of nutritional importance to <span class="hlt">vent</span> animals, and that at least one of these pathways is common to two geographically separated <span class="hlt">vent</span> <span class="hlt">sites</span>.</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/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> <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://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://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://pubs.er.usgs.gov/publication/70170844','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70170844"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> and methane seeps: Rethinking the sphere of influence</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Levin, Lisa A.; Baco, Amy; Bowden, David; Colaco, Ana; Cordes, Erik E.; Cunha, Marina; Demopoulos, Amanda; Gobin, Judith; Grupe, Ben; Le, Jennifer; Metaxas, Anna; Netburn, Amanda; Rouse, Greg; Thurber, Andrew; Tunnicliffe, Verena; Van Dover, Cindy L.; Vanreusel, Ann; Watling, Les</p> <p>2016-01-01</p> <p>Although initially viewed as oases within a barren deep ocean, <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> and methane seep communities are now recognized to interact with surrounding ecosystems on the sea floor and in the water column, and to affect global geochemical cycles. The importance of understanding these interactions is growing as the potential rises for disturbance from oil and gas extraction, seabed mining and bottom trawling. Here we synthesize current knowledge of the nature, extent and time and space scales of <span class="hlt">vent</span> and seep interactions with background systems. We document an expanded footprint beyond the <span class="hlt">site</span> of local <span class="hlt">venting</span> or seepage with respect to elemental cycling and energy flux, habitat use, trophic interactions, and connectivity. Heat and energy are released, global biogeochemical and elemental cycles are modified, and particulates are transported widely in plumes. Hard and biotic substrates produced at <span class="hlt">vents</span> and seeps are used by “benthic background” fauna for attachment substrata, shelter, and access to food via grazing or through position in the current, while particulates and fluid fluxes modify planktonic microbial communities. Chemosynthetic production provides nutrition to a host of benthic and planktonic heterotrophic background species through multiple horizontal and vertical transfer pathways assisted by flow, gamete release, animal movements, and succession, but these pathways remain poorly known. Shared species, genera and families indicate that ecological and evolutionary connectivity exists among <span class="hlt">vents</span>, seeps, organic falls and background communities in the deep sea; the genetic linkages with inactive <span class="hlt">vents</span> and seeps and background assemblages however, are practically unstudied. The waning of <span class="hlt">venting</span> or seepage activity generates major transitions in space and time that create links to surrounding ecosystems, often with identifiable ecotones or successional stages. The nature of all these interactions is dependent on water depth, as well as regional oceanography and biodiversity. Many ecosystem services are associated with the interactions and transitions between chemosynthetic and background ecosystems, for example carbon cycling and sequestration, fisheries production, and a host of non-market and cultural services. The quantification of the sphere of influence of <span class="hlt">vents</span> and seeps could be beneficial to better management of deep-sea environments in the face of growing industrialization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.V72A1282O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.V72A1282O"><span id="translatedtitle">Euryhaline Halophilic Microorganisms From the Suiyo Seamount <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>Okamoto, T.; Kimura, H.; Maruyama, A.; Naganuma, T.</p> <p>2002-12-01</p> <p>The euryhaline halophilic microorganisms grow in a wide salinity range from <3% NaCl (seawater equivalent) to >15% NaCl or to even saturation (about 30% NaCl). A number of euryhaline halophiles have been found in a wide range of habitats from oceanic and terrestrial regimes, from deep-sea <span class="hlt">vents</span> and seeps, and from Antarctic sea ice and terrains. We have isolated the euryhaline strains independently from a Mid-Atlantic Ridge <span class="hlt">vent</span> fluids and Antarctic terrains are closely related species of the genus Halomonas. Some euryhaline halophiles maintain intracellular osmotic balance by controlling the concentration of compatible solute such as ectoine. This compatible solute not only stabilizes the proteins from denaturation caused by high salt concentration but also serves as a protectant against stresses such as heating, freezing and drying. The sub-seafloor structure of a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> is highly complicated with mosaic heterogeneity of physicochemical parameters such as temperature and salinity. This premise led us to the hypothesis that some euryhaline halophiles including Halomonas species well adapt to a wide salinity-ranged habitat in the sub-<span class="hlt">vent</span>. To test this hypothesis, isolation and characterization of euryhaline halophiles from the Suiyo Seamount <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> were conducted the drill-cored rock samples from the <span class="hlt">sites</span> APSK-02, 03, and 07 and the filter-trapped fluid particle samples from the <span class="hlt">sites</span> APSK-01 and 05 were used. For initial cultivation, a heterotrophic bacterial medium of 15% NaCl was used. The samples was added to the medium and incubated under both aerobic and anaerobic conditions at room temperature. A total of 5 euryhaline halophilic strains were obtained and phylogenetically characterized: two strains (both related to Marinobacter) from APSK-02 core section 2; one strain (related to H. meridiana) from APSK-07 core section 3; and two strains (related to H. meridiana and H. variabilis) from APSK-01 trapped particles. In addition, some thermophilic halophiles that grow at 20% NaCl and 90 degree C were isolated from APSK-02, although phylogenetic and physioloigcal studies are under way. This research was supported by Archean Park project.</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://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3695286','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3695286"><span id="translatedtitle">Characterizing the distribution and rates of microbial sulfate reduction at Middle Valley <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>Frank, Kiana L; Rogers, Daniel R; Olins, Heather C; Vidoudez, Charles; Girguis, Peter R</p> <p>2013-01-01</p> <p>Few studies have directly measured sulfate reduction at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, and relatively little is known about how environmental or ecological factors influence rates of sulfate reduction in <span class="hlt">vent</span> environments. A better understanding of microbially mediated sulfate reduction in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystems may be achieved by integrating ecological and geochemical data with metabolic rate measurements. Here we present rates of microbially mediated sulfate reduction from three distinct <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the Middle Valley <span class="hlt">vent</span> field along the Juan de Fuca Ridge, as well as assessments of bacterial and archaeal diversity, estimates of total biomass and the abundance of functional genes related to sulfate reduction, and in situ geochemistry. Maximum rates of sulfate reduction occurred at 90 °C in all three deposits. Pyrosequencing and functional gene abundance data revealed differences in both biomass and community composition among <span class="hlt">sites</span>, including differences in the abundance of known sulfate-reducing bacteria. The abundance of sequences for Thermodesulfovibro-like organisms and higher sulfate reduction rates at elevated temperatures suggests that Thermodesulfovibro-like organisms may have a role in sulfate reduction in warmer environments. The rates of sulfate reduction presented here suggest that—within anaerobic niches of <span class="hlt">hydrothermal</span> deposits—heterotrophic sulfate reduction may be quite common and might contribute substantially to secondary productivity, underscoring the potential role of this process in both sulfur and carbon cycling at <span class="hlt">vents</span>. PMID:23535916</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950057135&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dhydrothermal','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950057135&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dhydrothermal"><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://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/11778945','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/11778945"><span id="translatedtitle">210Po and 210Pb cycling in a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> zone in the coastal Aegean sea.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Boisson, F; Miquel, J C; Cotret, O; Fowler, S W</p> <p>2001-12-17</p> <p>To quantify the potential enhancement of naturally-occurring 210Po and 210Pb that may result from the high sulfur-reducing and sulfur-oxidizing regimes associated with <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, sinking particles from both inside and outside <span class="hlt">vent</span> areas and benthic molluscs grazing on or living near bacterial mats in the <span class="hlt">vent</span> zone were collected off Milos Island (Aegean Sea) and analyzed for their 210Po and 210Pb content. There was no significant difference in the range of 210Po specific activities measured in particulate material collected by sediment traps in a control area and in the <span class="hlt">vent</span> area; the resultant 210Po levels were of the same order of magnitude as literature values reported for other Mediterranean coastal areas. 211Pb levels in sinking particles from the control <span class="hlt">site</span> tended to be higher than those measured in the <span class="hlt">vent</span> zone, as demonstrated by the lower 210Po/210Pb ratios observed in particles from the control <span class="hlt">site</span>. Nevertheless, these 210Pb levels were also comparable with similar 210Pb data reported for the northwestern Mediterranean Sea. The 210Po and 210Pb vertical particulate fluxes were, on average, higher in the <span class="hlt">vent</span> zone as a consequence of the higher particle flux. This observation indicates that <span class="hlt">vents</span> can indirectly control the flux of these natural radionuclides by affecting the types and amount of particles produced in <span class="hlt">hydrothermal</span> areas. The 210Po levels measured in a gastropod and a bivalve living on or near the microbial mat in the <span class="hlt">vent</span> zone were higher than values reported for non-<span class="hlt">vent</span> gastropods and bivalves from the NW Mediterranean Sea, an observation which suggests that an enhanced food chain transfer of 210Po may occur in the vicinity of <span class="hlt">vents</span> off Milos Island. Nevertheless, the lack of a general enhancement of 210Po and 210Pb in the marine particulate samples collected indicates that any input of these radionuclides through <span class="hlt">venting</span> activity may have a minimal effect in the surrounding environment. PMID:11778945</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMOS33F..05M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS33F..05M"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> at 5000m on the Mid-Cayman Rise: The Deepest and Hottest <span class="hlt">Hydrothermal</span> Systems Yet Discovered!</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Murton, B. J.; Connelly, D. P.; Copley, J. T.; Stansfield, K. L.; Tyler, P. A.; Cruise Jc044 Sceintific Party</p> <p>2010-12-01</p> <p>This contribution describes the geological setting of <span class="hlt">hydrothermal</span> activity within the Mid- Cayman Rise (MCR) using data acquired during cruise JC044 (MAR-APR 2010) from the deep-towed sidescan sonar TOBI, AUV Autosub6000 and the ROTV HyBIS. The 110 km-long Mid- Cayman Rise (MCR), located within Caribbean Sea, is the deepest spreading centre known, reaching over 6000m. Hence it poses an end-member of extreme depth for <span class="hlt">hydrothermal</span> circulation. Accretion of new volcanic crust is focused within two ridge segments, to the north and south of a centrally located massif of peridotite and gabbro. Following earlier indications of <span class="hlt">hydrothermal</span> plumes (German et al., in 2009), we discovered two high-temperature <span class="hlt">hydrothermal</span> system: one at a depth of 5000m in the neovolcanic zone of the northern segment, and another at 2300m on the flanks of the MCR. These <span class="hlt">sites</span> show contrasting styles of fluid <span class="hlt">venting</span>, mineralisation, geological setting and host rock interaction. At 5000m-depth, the ultra-deep <span class="hlt">vent</span> <span class="hlt">site</span> forms the deepest <span class="hlt">hydrothermal</span> system known. <span class="hlt">Venting</span> is focused at the western side of a 100m diameter, 30m high mound, while inactive sulphides extend eastwards for at least 800m. Fluids discharge from clusters of chimneys whose location is related to basement faults. Changes in salinity in the <span class="hlt">venting</span> fluids indicate discharge of a low salinity phase and a brine phase. At 500bar, this is definitive evidence for supercritical fluid emission. We also found the sulphide mineralization to be copper-rich, giving a characteristic green hue to many of the deposits, probably a result of the super-critical state of the <span class="hlt">vent</span> fluids. A prominent axial volcanic ridge nearby indicates a robust magma supply to the northern MCR segment. Thus it is likely the ultra-deep <span class="hlt">vent</span> <span class="hlt">site</span> derives its thermal energy from magmatic sources, similar to those thought to underlie other slow-spreading ridge volcanic-hosted <span class="hlt">vent</span> <span class="hlt">sites</span> (e.g. Broken Spur: MAR). The shallower (2300m) MCR <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">site</span> hosts vigorous medium-temperature fluid discharge from sulphide chimneys at the summit of an 80m diameter sulphide mound. Exiting <span class="hlt">vent</span> fluids are mostly clear with only traces of sulphide particulates. The chimneys are composed predominately of iron sulphides and calcium sulphate, with estimated fluid temperatures in the region of 150-250C. The <span class="hlt">vent</span> <span class="hlt">site</span> is located on a peridotite gabbro massif (Mt Dent), forming the western flank of the MCR. The morphology and lithology of Mt Dent indicates that it is an oceanic core complex, but in a dying stage. The axial volcanic ridge to the north has propagated into the OCC foot-wall and probably supplies the heat driving the <span class="hlt">hydrothermal</span> system. The only detectable signature from this <span class="hlt">vent</span> field is its low Eh plume. As a result, we believe that this style of <span class="hlt">venting</span> has hitherto been overlooked, and thus its global significance for the cooling and alteration of slow-spread oceanic crust may be greatly underestimated.</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/2010AGUFMOS13G..07B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS13G..07B"><span id="translatedtitle">Larval abundance and dispersal at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the southern Mariana Trough</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.; Watanabe, H.; Mills, S. W.; Pradillon, F.; Kojima, S.; Mullineaux, L. S.</p> <p>2010-12-01</p> <p>Since the discovery of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> over thirty years ago, scientists have been perplexed by the question: “How are the faunal populations established and maintained at these very discrete and often ephemeral habitats?” For the animals that are sessile or have limited mobility as adults, dispersal to these habitats occurs early in the life cycle, as planktonic larvae in the water column. Due to the difficulties in sampling deep-sea larvae, including low abundances (dilute concentrations), we have very few quantitative estimates of larval dispersal between or larval supply to <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Here, we will present results of an international, collaborative effort to study larval abundance and dispersal at <span class="hlt">vents</span> near the back-arc spreading center in the southern Mariana Trough. On R/V Yokosuka cruise YK10-11 in September 2010, we will deploy large-volume plankton pumps at approximately 3000-m depth at Snail (also called South Backarc), Archaean, and Pika, three of the <span class="hlt">Vents</span> (Volcanic) Unit <span class="hlt">sites</span> in the U.S. Marianas Trench Marine National Monument. These <span class="hlt">vents</span> are being studied as part of the Japanese multi-disciplinary program TAIGA (Trans-crustal Advection and In-situ biogeochemical proceses of Global sub-sea floor Aquifer). These will be the first collections of <span class="hlt">vent</span> larvae in the Mariana back-arc, and we will compare the abundances and diversity of larvae to similar work conducted at the Ridge 2000 East Pacific Rise Integrated Studies <span class="hlt">Site</span>. We will deploy a current meter near the Snail <span class="hlt">site</span> (on-axis) for preliminary estimates of passive larval transport on the time scale of the cruise. The three study <span class="hlt">sites</span> are situated in a line perpendicular to the back-arc spreading axis, and thus may be interesting in terms of local dispersal processes. Perhaps more interesting, however, is that the back-arc <span class="hlt">vents</span> that we will visit are as close as 25 km to known <span class="hlt">vents</span> on the arc, yet 600 km south of the other known <span class="hlt">vents</span> in the back-arc. These two tectonic settings create different habitat conditions and support <span class="hlt">vent</span> communities with different species composition. Will we collect larvae of species that are commonly found at (generally shallower) <span class="hlt">vents</span> on the Mariana arc? The larval studies will help address the question of how populations of <span class="hlt">vent</span>-endemic species are connected at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> within the new Marine National Monument.</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://www.ncbi.nlm.nih.gov/pubmed/24444808','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24444808"><span id="translatedtitle">Metal concentrations in the tissues of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel Bathymodiolus: reflection of different metal sources.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Koschinsky, Andrea; Kausch, Matteo; Borowski, Christian</p> <p>2014-04-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> mussels of the genus Bathymodiolus are ideally positioned for the use of recording <span class="hlt">hydrothermal</span> fluxes at the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> they inhabit. Barium, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Pb, Sr, and U concentrations in tissue sections of Bathymodiolus mussels from several <span class="hlt">hydrothermal</span> fields between 15°N and 9°S at the Mid-Atlantic Ridge were determined and compared to the surrounding fluids and solid substrates in the habitats. Elements generally enriched in <span class="hlt">hydrothermal</span> fluids, such as Fe, Cu, Zn, Pb and Cd, were significantly enriched in the gills and digestive glands of the <span class="hlt">hydrothermal</span> mussels. The rather small variability of Zn (and Mn) and positive correlation with K and earth alkaline metals may indicate a biological regulation of accumulation. Enrichments of Mo and U in many tissue samples indicate that particulate matter such as <span class="hlt">hydrothermal</span> mineral particles from the plumes can play a more important role as a metal source than dissolved metals. Highest enrichments of Cu in mussels from the Golden Valley <span class="hlt">site</span> indicate a relation to the ≥400 °C hot heavy-metal rich fluids emanating in the vicinity. In contrast, mussels from the low-temperature Lilliput field are affected by the Fe oxyhydroxide sediment of their habitat. In a comparison of two different <span class="hlt">sites</span> within the Logatchev field metal distributions in the tissues reflected small-scale local variations in the metal content of the fluids and the particulate material. PMID:24444808</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060042927&hterms=dives&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Ddives','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060042927&hterms=dives&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Ddives"><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://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://adsabs.harvard.edu/abs/2010AGUFMOS33F..03R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS33F..03R"><span id="translatedtitle">Investigations of a novel fauna from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> along the Arctic Mid-Ocean Ridge (AMOR) (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rapp, H.; Schander, C.; Halanych, K. M.; Levin, L. A.; Sweetman, A.; Tverberg, J.; Hoem, S.; Steen, I.; Thorseth, I. H.; Pedersen, R.</p> <p>2010-12-01</p> <p>The Arctic deep ocean hosts a variety of habitats ranging from fairly uniform sedimentary abyssal plains to highly variable hard bottoms on mid ocean ridges, including biodiversity hotspots like seamounts and <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. 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. This fauna includes various animal groups of which the most conspicuous and well known are annelids, mollusks and crustaceans. The newly discovered deep sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the Mohns-Knipovich ridge north of Iceland harbour unique biodiversity. The Jan Mayen field consists of two main areas with high-temperature white smoker <span class="hlt">venting</span> and wide areas with low-temperature seepage, located at 5-700 m, while the deeper Loki Castle <span class="hlt">vent</span> field at 2400 m depth consists of a large area with high temperature black smokers surrounded by a sedimentary area with more diffuse low-temperature <span class="hlt">venting</span> and barite chimneys. The Jan Mayen <span class="hlt">sites</span> show low abundance of specialized <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fauna. Single groups have a few specialized representatives but groups otherwise common in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> areas are absent. Slightly more than 200 macrofaunal species have been identified from this <span class="hlt">vent</span> area, comprising mainly an assortment of bathyal species known from the surrounding area. Analysis of stable isotope data also indicates that the majority of the species present are feeding on phytodetritus and/or phytoplankton. However, the deeper Loki Castle <span class="hlt">vent</span> field contains a much more diverse <span class="hlt">vent</span> endemic fauna with high abundances of specialized polychaetes, gastropods and amphipods. These specializations also include symbioses with a range of chemosynthetic microorganisms. Our data show that the fauna composition is a result of high degree of local specialization with some similarities to the fauna of cold seeps along the Norwegian margin and wood-falls in the abyssal Norwegian Sea. Few species are common to both the deep and the shallow <span class="hlt">vents</span>, but some gastropod species show a structured population difference between the <span class="hlt">sites</span>. Our data indicate that there has been a migration of <span class="hlt">vent</span> fauna into the Arctic Ocean from the Pacific Ocean rather than from the known <span class="hlt">vent</span> <span class="hlt">sites</span> further south in the Atlantic Ocean. The discovery and sampling of these new arctic <span class="hlt">vent</span> fields provide unique data to further understand the migration of <span class="hlt">vent</span> organisms and interactions between different deep sea chemosynthetic environments. Based on the high degree of local adaptation and specialization of fauna from the studied <span class="hlt">sites</span> we propose the AMOR to be a new zoogeographical province for <span class="hlt">vent</span> fauna.</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/22620276','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22620276"><span id="translatedtitle">Scientific gear as a vector for non-native species 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>Voight, Janet R; Lee, Raymond W; Reft, Abigail J; Bates, Amanda E</p> <p>2012-10-01</p> <p>The fauna of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are among the most isolated and inaccessible biological communities on Earth. Most <span class="hlt">vent</span> <span class="hlt">sites</span> can only be visited by subsea vehicles, which can and do move freely among these communities. Researchers assume individuals of the regionally homogeneous <span class="hlt">vent</span> fauna are killed by the change in hydrostatic pressure the animals experience when the subsea vehicles, which collected them, rise to the surface. After an Alvin dive, we found 38 apparently healthy individuals of a <span class="hlt">vent</span> limpet in a sample from a <span class="hlt">hydrothermally</span> inactive area. Prompted by our identification of these specimens as Lepetodrilus gordensis, a species restricted to <span class="hlt">vents</span> 635 km to the south of our dive <span class="hlt">site</span>, we tested whether they were from a novel population or were contaminants from the dive made 36 h earlier. The 16S gene sequences, morphology, sex ratio, bacterial colonies, and stable isotopes uniformly indicated the specimens came from the previous dive. We cleaned the sampler, but assumed pressure changes would kill any organisms we did not remove and that the faunas of the 2 areas were nearly identical and disease-free. Our failure to completely clean the gear on the subsea vehicle meant we could have introduced the species and any diseases it carried to a novel location. Our findings suggest that the nearly inaccessible biological communities at deep-sea <span class="hlt">vents</span> may be vulnerable to anthropogenic alteration, despite their extreme physical conditions. PMID:22620276</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.H13C1412L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.H13C1412L"><span id="translatedtitle">The isotopic composition of dissolved inorganic nitrogen in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lehmann, M. F.; Bourbonnais, A.; Butterfield, D. A.</p> <p>2006-12-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> systems at mid-ocean ridges are <span class="hlt">sites</span> with rapid rates of biomass production, sustained by chemolithoautotrophic bacteria at the base of the <span class="hlt">vent</span> community food chains. The exact metabolic pathways, in particular those that involve nitrogen (N), and the rates at which the metabolic reactions take place are poorly constrained. In previous studies, very low 15N/14N ratios have been attributed to strong N isotope fractionation during chemosynthetic assimilation of ammonium. However, actual data on the N isotopic composition of dissolved inorganic N in <span class="hlt">vent</span> systems, which could provide coherent information on the sources of N during chemolithoautotrophic biosynthesis, do not exist. Furthermore, the fate of <span class="hlt">hydrothermally</span> discharged ammonium as well as that of nitrate that is mixed in from the ocean water column have not been the focus of much attention. As a consequence, little is known about N-cycle reactions within <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems. We will present nitrate isotope (15N/14N and 18O/16O) data from various <span class="hlt">sites</span> at Axial Volcano on the Juan de Fuca ridge. Their integration with nitrate concentration data suggests non-conservative behavior of nitrate along temperature gradients. Highest N and O isotope ratios (7.6 permil and 21.0 permil, respectively) are found in average diffuse fluids (17°C). Elevated N and O isotope ratios were associated with decreased nitrate concentrations and indicate a nitrate consuming process that fractionates both N and O isotopes. The ratio of 15N versus 18O enrichment in residual nitrate is, however, not consistent with previous reports on nitrate N versus O isotope fractionation during denitrification in the suboxic ocean water column, implying anomalous N and O isotope fractionation during denitrification in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids and/or the presence of additional microbially mediated N transformations that affect the N and O isotope composition of the nitrate pool in the Axial <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> system in a fundamentally different way. More nitrate isotope measurements from other <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems will be conducted in order to investigate the possible mechanisms behind the observed N-to-O nitrate isotope anomaly. In addition, we plan to present data on the N isotopic composition of ammonium from ammonium-rich <span class="hlt">vent</span> fluids from the Endeavour segment of the Juan de Fuca ridge (upcoming cruise Aug. 13 to Sep. 8). We anticipate that the assessment of principal patterns of ammonium N-isotope dynamics at Endeavour <span class="hlt">sites</span> will help to study the activity of ammonium oxidizing organisms, as well as to gain constraints on the source of N during bacterial N assimilation in this particular geomicrobial ecosystem.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1988DSRA...35.1811F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988DSRA...35.1811F"><span id="translatedtitle">Variation in the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> clam, Calyptogen magnifica, at the Rose Garden <span class="hlt">vent</span> on the 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>Fisher, C. R.; Childress, J. J.; Arp, A. J.; Brooks, J. M.; Distel, D. L.; Dugan, J. A.; Felbeck, H.; Fritz, L. W.; Hessler, R. R.; Johnson, K. S.; Kennicutt, M. C.; Lutz, R. A.; Macko, S. A.; Newton, A.; Powell, M. A.; Somero, G. N.; Soto, T.</p> <p>1988-10-01</p> <p>Calyptogena magnifica occupy a relatively restricted habitat at the Rose Garden <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">site</span> on the Galapagos Rift. These clams are found in areas with very low flow of <span class="hlt">vent</span> water and gain exposure to hydrogen sulfide by inserting their well-vascularized foot into cracks that contain this flow. <span class="hlt">Vent</span> water is undetectable around the siphons of many of the individuals, and they therefore probably take up sulfide through their foot, and oxygen and inorganic carbon through their gills. Age estimates indicate that the bulk of the recruitment of C. magnifica occured between 1971 and 1976. Isotopic evidence indicates that symbionts are the main source of both nutritional carbon and nitrogen for the clams, and that the symbionts assimilate both of these substrates from inorganic sources. Carbohydrate and protein in the clam soft tissues, as well as the elemental sulfur content of their gills, decrease with increasing clam size. There is only slight variation in most of the parameters measured, and none of the parameters show nearly the variation seen in the other <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> bivalve, Bathymodiolus thermophilus. However, several parameters, such as ?13C, condition index, and some bacterial enzyme activities, vary significantly with habitat.</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://www.ncbi.nlm.nih.gov/pubmed/12712202','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12712202"><span id="translatedtitle">Magmatic events can produce rapid changes in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chemistry.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lilley, Marvin D; Butterfield, David A; Lupton, John E; Olson, Eric J</p> <p>2003-04-24</p> <p>The Endeavour segment of the Juan de Fuca ridge is host to one of the most vigorous <span class="hlt">hydrothermal</span> areas found on the global mid-ocean-ridge system, with five separate <span class="hlt">vent</span> fields located within 15 km along the top of the ridge segment. Over the past decade, the largest of these <span class="hlt">vent</span> fields, the 'Main Endeavour Field', has exhibited a constant spatial gradient in temperature and chloride concentration in its <span class="hlt">vent</span> fluids, apparently driven by differences in the nature and extent of subsurface phase separation. This stable situation was disturbed on 8 June 1999 by an earthquake swarm. Owing to the nature of the seismic signals and the lack of new lava flows observed in the area during subsequent dives of the Alvin and Jason submersibles (August-September 1999), the event was interpreted to be tectonic in nature. Here we show that chemical data from <span class="hlt">hydrothermal</span> fluid samples collected in September 1999 and June 2000 strongly suggest that the event was instead volcanic in origin. Volatile data from this event and an earlier one at 9 degrees N on the East Pacific Rise show that such magmatic events can have profound and rapid effects on fluid-mineral equilibria, phase separation, 3He/heat ratios and fluxes of volatiles from submarine <span class="hlt">hydrothermal</span> systems. PMID:12712202</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://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://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://adsabs.harvard.edu/abs/2002GeoRL..29.1744W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002GeoRL..29.1744W"><span id="translatedtitle">Ambient light emission from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on 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>White, Sheri N.; Chave, Alan D.; Reynolds, George T.; Van Dover, Cindy L.</p> <p>2002-08-01</p> <p>A spectral imaging camera was used to observe light emission from high-temperature, deep-sea <span class="hlt">vents</span> at three <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> on the Mid-Atlantic Ridge (MAR): Logatchev, Snake Pit, and Lucky Strike. Ambient light measured at these <span class="hlt">sites</span> is similar to that observed at <span class="hlt">sites</span> along the East Pacific Rise and the Juan de Fuca Ridge, with components from both thermal and non-thermal sources. The shrimp species Rimicaris exoculata, which is found on the MAR but not in the Eastern Pacific, possesses a unique photoreceptor capable of detecting low light levels. It is not yet known if R. exoculata ``sees'' <span class="hlt">vent</span> light. However, since the characteristics of <span class="hlt">vent</span> light appear to be unrelated to geographical location, the exclusion of R. exoculata from the Eastern Pacific is probably unrelated to differences in ambient light conditions.</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://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> </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://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/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://adsabs.harvard.edu/abs/2012AGUFM.B41F..03H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.B41F..03H"><span id="translatedtitle">Subseafloor Microbial Life in <span class="hlt">Venting</span> Fluids from the Mid Cayman Rise <span class="hlt">Hydrothermal</span> System</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.; Reddington, E.; McDermott, J. M.; Sylva, S. P.; Breier, J. A.; German, C. R.; Seewald, J.</p> <p>2012-12-01</p> <p>In hard rock seafloor environments, fluids emanating from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are one of the best windows into the subseafloor and its resident microbial community. The functional consequences of an extensive population of microbes living in the subseafloor remains unknown, as does our understanding of how these organisms interact with one another and influence the biogeochemistry of the oceans. Here we report the abundance, activity, and diversity of microbes in <span class="hlt">venting</span> fluids collected from two newly discovered deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> along the ultra-slow spreading Mid-Cayman Rise (MCR). Fluids for geochemical and microbial analysis were collected from the Von Damm and Piccard <span class="hlt">vent</span> fields, which are located within 20 km of one another, yet have extremely different thermal, geological, and depth regimes. Geochemical data indicates that both fields are highly enriched in volatiles, in particular hydrogen and methane, important energy sources for and by-products of microbial metabolism. At both <span class="hlt">sites</span>, total microbial cell counts in the fluids ranged in concentration from 5 x 10 4 to 3 x 10 5 cells ml-1 , with background seawater concentrations of 1-2 x 10 4 cells ml-1 . In addition, distinct cell morphologies and clusters of cells not visible in background seawater were seen, including large filaments and mineral particles colonized by microbial cells. These results indicate local enrichments of microbial communities in the <span class="hlt">venting</span> fluids, distinct from background populations, and are consistent with previous enumerations of microbial cells in <span class="hlt">venting</span> fluids. Stable isotope tracing experiments were used to detect utilization of acetate, formate, and dissolve inorganic carbon and generation of methane at 70 °C under anaerobic conditions. At Von Damm, a putatively ultra-mafic hosted <span class="hlt">site</span> located at ~2200 m with a maximum temperature of 226 °C, stable isotope tracing experiments indicate methanogenesis is occurring in most fluid samples. No activity was detected in Piccard <span class="hlt">vent</span> fluids, a basalt-hosted black smoker <span class="hlt">site</span> located at ~4950 m with a maximum temperature of 403 °C. However, hyperthermophilic and thermophilic heterotrophs of the genus Thermococcus were isolated from Piccard <span class="hlt">vent</span> fluids, but not Von Damm. These obligate anaerobes, growing optimally at 55-90 °C, are ubiquitous at <span class="hlt">hydrothermal</span> systems and serve as a readily cultivable indicator organism of subseafloor populations. Finally, molecular analysis of <span class="hlt">vent</span> fluids is on-going and will define the microbial population structure in this novel ecosystem and allow for direct comparisons with other deep-sea and subsurface habitats as part of our continuing efforts to explore the deep microbial biosphere on Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016NatSR...622163N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016NatSR...622163N"><span id="translatedtitle">Rapid growth of mineral deposits at artificial 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>Nozaki, Tatsuo; Ishibashi, Jun-Ichiro; Shimada, Kazuhiko; Nagase, Toshiro; Takaya, Yutaro; Kato, Yasuhiro; Kawagucci, Shinsuke; Watsuji, Tomoo; Shibuya, Takazo; Yamada, Ryoichi; Saruhashi, Tomokazu; Kyo, Masanori; Takai, Ken</p> <p>2016-02-01</p> <p>Seafloor massive sulphide deposits are potential resources for base and precious metals (Cu-Pb-Zn ± Ag ± Au), but difficulties in estimating precise reserves and assessing environmental impacts hinder exploration and commercial mining. Here, we report petrological and geochemical properties of sulphide chimneys less than 2 years old that formed where scientific boreholes <span class="hlt">vented</span> <span class="hlt">hydrothermal</span> fluids in the Iheya-North field, Okinawa Trough, in East China Sea. One of these infant chimneys, dominated by Cu-Pb-Zn-rich sulphide minerals, grew a height of 15 m within 25 months. Portions of infant chimneys are dominated by sulphate minerals. Some infant chimneys are sulphide-rich similar to high-grade Cu-Pb-Zn bodies on land, albeit with relatively low As and Sb concentrations. The high growth rate reaching the 15 m height within 25 months is attributed to the large <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> more than 50 cm in diameter created by the borehole, which induced slow mixing with the ambient seawater and enhanced efficiency of sulphide deposition. These observations suggest the possibility of cultivating seafloor sulphide deposits and even controlling their growth and grades through manipulations of how to mix and quench <span class="hlt">hydrothermal</span> fluids with the ambient seawater.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26911272','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26911272"><span id="translatedtitle">Rapid growth of mineral deposits at artificial seafloor <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>Nozaki, Tatsuo; Ishibashi, Jun-Ichiro; Shimada, Kazuhiko; Nagase, Toshiro; Takaya, Yutaro; Kato, Yasuhiro; Kawagucci, Shinsuke; Watsuji, Tomoo; Shibuya, Takazo; Yamada, Ryoichi; Saruhashi, Tomokazu; Kyo, Masanori; Takai, Ken</p> <p>2016-01-01</p> <p>Seafloor massive sulphide deposits are potential resources for base and precious metals (Cu-Pb-Zn ± Ag ± Au), but difficulties in estimating precise reserves and assessing environmental impacts hinder exploration and commercial mining. Here, we report petrological and geochemical properties of sulphide chimneys less than 2 years old that formed where scientific boreholes <span class="hlt">vented</span> <span class="hlt">hydrothermal</span> fluids in the Iheya-North field, Okinawa Trough, in East China Sea. One of these infant chimneys, dominated by Cu-Pb-Zn-rich sulphide minerals, grew a height of 15 m within 25 months. Portions of infant chimneys are dominated by sulphate minerals. Some infant chimneys are sulphide-rich similar to high-grade Cu-Pb-Zn bodies on land, albeit with relatively low As and Sb concentrations. The high growth rate reaching the 15 m height within 25 months is attributed to the large <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> more than 50 cm in diameter created by the borehole, which induced slow mixing with the ambient seawater and enhanced efficiency of sulphide deposition. These observations suggest the possibility of cultivating seafloor sulphide deposits and even controlling their growth and grades through manipulations of how to mix and quench <span class="hlt">hydrothermal</span> fluids with the ambient seawater. PMID:26911272</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://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4766430','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4766430"><span id="translatedtitle">Rapid growth of mineral deposits at artificial seafloor <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>Nozaki, Tatsuo; Ishibashi, Jun-Ichiro; Shimada, Kazuhiko; Nagase, Toshiro; Takaya, Yutaro; Kato, Yasuhiro; Kawagucci, Shinsuke; Watsuji, Tomoo; Shibuya, Takazo; Yamada, Ryoichi; Saruhashi, Tomokazu; Kyo, Masanori; Takai, Ken</p> <p>2016-01-01</p> <p>Seafloor massive sulphide deposits are potential resources for base and precious metals (Cu-Pb-Zn ± Ag ± Au), but difficulties in estimating precise reserves and assessing environmental impacts hinder exploration and commercial mining. Here, we report petrological and geochemical properties of sulphide chimneys less than 2 years old that formed where scientific boreholes <span class="hlt">vented</span> <span class="hlt">hydrothermal</span> fluids in the Iheya-North field, Okinawa Trough, in East China Sea. One of these infant chimneys, dominated by Cu-Pb-Zn-rich sulphide minerals, grew a height of 15 m within 25 months. Portions of infant chimneys are dominated by sulphate minerals. Some infant chimneys are sulphide-rich similar to high-grade Cu-Pb-Zn bodies on land, albeit with relatively low As and Sb concentrations. The high growth rate reaching the 15 m height within 25 months is attributed to the large <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> more than 50 cm in diameter created by the borehole, which induced slow mixing with the ambient seawater and enhanced efficiency of sulphide deposition. These observations suggest the possibility of cultivating seafloor sulphide deposits and even controlling their growth and grades through manipulations of how to mix and quench <span class="hlt">hydrothermal</span> fluids with the ambient seawater. PMID:26911272</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.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/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/2005DSRI...52.1528W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005DSRI...52.1528W"><span id="translatedtitle">Are midwater shrimp trapped in the craters of submarine volcanoes by <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>Wishner, Karen F.; Graff, Jason R.; Martin, Joel W.; Carey, S.; Sigurdsson, H.; Seibel, B. A.</p> <p>2005-08-01</p> <p>The biology of Kick'em Jenny (KEJ) submarine volcano, part of the Lesser Antilles volcanic arc and located off the coast of Grenada in the Caribbean Sea, was studied during a cruise in 2003. <span class="hlt">Hydrothermal</span> <span class="hlt">venting</span> and an associated biological assemblage were discovered in the volcanic crater (˜250 m depth). Warm water with bubbling gas emanated through rock fissures and sediments. Shrimp (some of them swimming) were clustered at <span class="hlt">vents</span>, while other individuals lay immobile on sediments. The shrimp fauna consisted of 3 mesopelagic species that had no prior record of benthic or <span class="hlt">vent</span> association. We suggest that these midwater shrimp, from deeper water populations offshore, were trapped within the crater during their downward diel vertical migration. It is unknown whether they then succumbed to the hostile <span class="hlt">vent</span> environment (immobile individuals) or whether they are potentially opportunistic <span class="hlt">vent</span> residents (active individuals). Given the abundance of submarine arc volcanoes worldwide, this phenomenon suggests that volcanic arcs could be important interaction <span class="hlt">sites</span> between oceanic midwater and <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://adsabs.harvard.edu/abs/2010AGUFMOS13C1236B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS13C1236B"><span id="translatedtitle">Video Observations by Telepresence Reveal Two Types of <span class="hlt">Hydrothermal</span> <span class="hlt">Venting</span> on Kawio Barat Seamount</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Butterfield, D. A.; Holden, J. F.; Shank, T. M.; Tunnicliffe, V.; Sherrin, J.; Herrera, S.; Baker, E. T.; Lovalvo, D.; Makarim, S.; Malik, M. A.; Wirasantosa, S.; Hammond, S. R.</p> <p>2010-12-01</p> <p>The INDEX-SATAL 2010 expedition began an international exploration of the seafloor in Indonesian waters using the methodology of telepresence, conducting EM302 multibeam mapping, water column CTD, and ROV high-definition video operations and sending data back to Exploration Command Centers in Indonesia and Seattle. Science observers in other locations in the US and Canada were engaged in real-time observations and interpretation of results. One mission goal was to locate <span class="hlt">hydrothermal</span> or volcanic activity. Intense light scattering and redox potential measurements in the water column over Kawio Barat (KB)indicated a high level of <span class="hlt">hydrothermal</span> activity, and direct video observations confirmed <span class="hlt">venting</span> near the summit. None of the other volcanic features west of the Sangihe arc that were investigated during the mission had confirmed <span class="hlt">hydrothermal</span> activity. ROV capabilities did not include physical sampling or temperature measurement, so our interpretation is based on visual comparison to other known <span class="hlt">sites</span>. The steep western flank of KB from 2000 m depth to the summit (1850 m) has many areas of white and orange staining on exposed rocks, with some elemental sulfur, and broad areas covered with dark volcaniclastic sand, but no active <span class="hlt">venting</span> was seen. KB has a summit ridge running WNW-ESE, with a major cross-cutting ridge on the western portion of the summit. <span class="hlt">Hydrothermal</span> activity is concentrated near the eastern side of this intersection, on both the northern and southern sides of the summit ridge. <span class="hlt">Venting</span> on the northern side of the summit ridge is characterized by intense white particle-rich fluids emanating directly from the rocky substrate with frozen flows of elemental sulfur down slope. This type of <span class="hlt">venting</span> is visually very similar to the <span class="hlt">venting</span> seen on NW Rota-1, an actively erupting volcano in the Mariana arc, and suggests that KB is actively releasing magmatic gases rich in sulfur dioxide to produce the elemental sulfur flows, inferred fine particulate sulfur particles, and apparent acidic alteration. These <span class="hlt">hydrothermal</span> features along with the widespread occurrence of volcaniclastic deposits near the summit suggest that Kawio Barat has experienced recent eruptive activity. In contrast, however, the south side of the summit has active metal sulfide chimneys <span class="hlt">venting</span> clear to gray/black fluids. The <span class="hlt">vents</span> seen on the south slope appear identical to <span class="hlt">vents</span> detected by camera tow and reported by McConnachy et al. 2004. The visually dominant <span class="hlt">vent</span> fauna is a stalked barnacle that covers much of the chimney surfaces. The apparently stable hot <span class="hlt">vents</span> on the south flank require a reaction zone with low water/rock ratio at depth within the volcano. Some aspect of the volcanic/<span class="hlt">hydrothermal</span> plumbing at KB produces a separation of magmatic gases (north summit slope) from circulating <span class="hlt">hydrothermal</span> fluids (south summit slope).</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://www.osti.gov/scitech/biblio/85441','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/85441"><span id="translatedtitle">Effluent from diffuse <span class="hlt">hydrothermal</span> <span class="hlt">venting</span>. 1: A simple model of plumes from diffuse <span class="hlt">hydrothermal</span> sources</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Trivett, D.A.</p> <p>1994-09-01</p> <p>This paper focuses on modeling the fate of effluent from diffuse seafloor <span class="hlt">hydrothermal</span> activity after it has been <span class="hlt">vented</span> into the water column. The model was formulated using a number of simplifying assumptions which permit direct application of this model to field measurements. I have limited the configurations to those where the <span class="hlt">hydrothermal</span> outflow velocities are smaller than horizontal current. I assume that the entrainment of ambient seawater into the plume is constant over the length of the plume. This permits formulation of a first-order relation for the rise height and dilution in a diffuse <span class="hlt">hydrothermal</span> plume as a function of downstream distance. The analytic model is compared with a simple laboratory simulation of the <span class="hlt">hydrothermal</span> flow. The results suggest that diffuse <span class="hlt">hydrothermal</span> effluent will penetrate to a height in the water column that is proportional to the overall dimension of the diffuse <span class="hlt">vent</span> patch, multiplied by a dimensionless plume intensity parameter. I also ahow relations for plume dilution which will be compared with field data in part 2 of this work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19050821','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19050821"><span id="translatedtitle">Bacterial and archaeal populations at two shallow <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> off Panarea Island (Eolian Islands, Italy).</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Maugeri, Teresa Luciana; Lentini, Valeria; Gugliandolo, Concetta; Italiano, Francesco; Cousin, Sylvie; Stackebrandt, Erko</p> <p>2009-01-01</p> <p>The aim of this study was to investigate the microbial community thriving at two shallow <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> off Panarea Island (Italy). Physico-chemical characteristics of thermal waters were examined in order to establish the effect of the <span class="hlt">vents</span> on biodiversity of both Bacteria and Archaea. Water and adjacent sediment samples were collected at different times from two <span class="hlt">vents</span>, characterised by different depth and temperature, and analysed to evaluate total microbial abundances, sulphur-oxidising and thermophilic aerobic bacteria. Total microbial abundances were on average of the order of 10(5) cells ml(-1), expressed as picoplanktonic size fraction. Picophytoplanktonic cells accounted for 0.77-3.83% of the total picoplanktonic cells. The contribution of bacterial and archaeal taxa to prokaryotic community diversity was investigated by PCR-DGGE fingerprinting method. The number of bands derived from bacterial DNA was highest in the DGGE profiles of water sample from the warmest and deepest <span class="hlt">site</span> (<span class="hlt">site</span> 2). In contrast, archaeal richness was highest in the water of the coldest and shallowest <span class="hlt">site</span> (<span class="hlt">site</span> 1). Sulphur-oxidising bacteria were detected by both culture-dependent and -independent methods. The primary production at the shallow <span class="hlt">hydrothermal</span> system of Panarea is supported by a complex microbial community composed by phototrophs and chemolithotrophs. PMID:19050821</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840031038&hterms=hydrothermal+vent&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhydrothermal%2Bvent','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840031038&hterms=hydrothermal+vent&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhydrothermal%2Bvent"><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://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://www.ncbi.nlm.nih.gov/pubmed/26626941','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26626941"><span id="translatedtitle">Characterization of Bacterial Communities in Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> from Three Oceanic Regions.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>He, Tianliang; Zhang, Xiaobo</p> <p>2016-04-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are considered to be one of the most spectacular ecosystems on Earth. Microorganisms form the basis of the food chain in <span class="hlt">vents</span> controlling the <span class="hlt">vent</span> communities. However, the diversity of bacterial communities in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> from different oceans remains largely unknown. In this study, the pyrosequencing of 16S rRNA gene was used to characterize the bacterial communities of the <span class="hlt">venting</span> sulfide, seawater, and tubeworm trophosome from East Pacific Rise, South Atlantic Ridge, and Southwest Indian Ridge, respectively. A total of 23,767 operational taxonomic units (OTUs) were assigned into 42 different phyla. Although Proteobacteria, Actinobacteria, and Bacteroidetes were the predominant phyla in all <span class="hlt">vents</span>, differences of bacterial diversity were observed among different <span class="hlt">vents</span> from three oceanic regions. The sulfides of East Pacific Rise possessed the most diverse bacterial communities. The bacterial diversities of <span class="hlt">venting</span> seawater were much lower than those of <span class="hlt">vent</span> sulfides. The symbiotic bacteria of tubeworm Ridgeia piscesae were included in the bacterial community of <span class="hlt">vent</span> sulfides, suggesting their significant ecological functions as the primary producers in the deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystems. Therefore, our study presented a comprehensive view of bacterial communities in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> from different oceans. PMID:26626941</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26475295','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26475295"><span id="translatedtitle">Lipid Adaptation of Shrimp Rimicaris exoculata in <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>Zhu, Si; Ye, Mengwei; Yan, Xiaojun; Zhou, Yadong; Wang, Chunsheng; Xu, Jilin</p> <p>2015-12-01</p> <p>The shrimp Rimicaris exoculata is the most abundant species in <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Lipids, the component of membranes, play an important role in maintaining their function normally in such extreme environments. In order to understand the lipid adaptation of R. exoculata (HV shrimp) to <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, we compared its lipid profile with the coastal shrimp Litopenaeus vannamei (EZ shrimp) which lives in the euphotic zone, using ultra performance liquid chromatography electrospray ionization-quadrupole time-of-flight mass spectrometry. As a result, the following lipid adaptation can be observed. (1) The proportion of 16:1 and 18:1, and non-methylene interrupted fatty acid (48.9 and 6.2 %) in HV shrimp was higher than that in EZ shrimp (12.7 and 0 %). While highly-unsaturated fatty acids were only present in the EZ shrimp. (2) Ceramide and sphingomyelin in the HV shrimp were enriched in d14:1 long chain base (96.5 and 100 %) and unsaturated fatty acids (67.1 and 57.7 %). While in the EZ shrimp, ceramide and sphingomyelin had the tendency to contain d16:1 long chain base (68.7 and 75 %) and saturated fatty acids (100 and 100 %). (3) Triacylglycerol content (1.998 ± 0.005 nmol/mg) in the HV shrimp was higher than that in the EZ shrimp (0.092 ± 0.005 nmol/mg). (4) Phosphatidylinositol and diacylglycerol containing highly-unsaturated fatty acids were absent from the HV shrimp. (5) Lysophosphatidylcholine and lysophosphatidylethanolamine were rarely detected in the HV shrimp. A possible reason for such differences was the result of food resources and inhabiting environments. Therefore, these lipid classes mentioned above may be the biomarkers to compare the organisms from different environments, which will be benefit for the further exploitation of the <span class="hlt">hydrothermal</span> environment. PMID:26475295</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://adsabs.harvard.edu/abs/2004GGG.....5.8002B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004GGG.....5.8002B"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baker, Edward T.; Edmonds, Henrietta N.; Michael, Peter J.; Bach, Wolfgang; Dick, Henry J. B.; Snow, Jonathan E.; Walker, Sharon L.; Banerjee, Neil R.; Langmuir, Charles H.</p> <p>2004-08-01</p> <p>Detailed <span class="hlt">hydrothermal</span> surveys over ridges with spreading rates of 50-150 mm/yr have found a linear relation between spreading rate and the spatial frequency 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 compare <span class="hlt">hydrothermal</span> plume surveys along three sections of the Gakkel Ridge (Arctic Ocean) and the Southwest Indian Ridge (SWIR) to determine if <span class="hlt">hydrothermal</span> activity is similarly distributed among these ultraslow ridge sections and if these distributions follow the hypothesized linear trend derived from surveys along fast ridges. Along the Gakkel Ridge, most apparent <span class="hlt">vent</span> <span class="hlt">sites</span> occur on volcanic highs, and the extraordinarily weak vertical density gradient of the deep Arctic permits plumes to rise above the axial bathymetry. Individual plumes can thus be extensively dispersed along axis, to distances >200 km, and ˜75% of the total axial length surveyed is overlain by plumes. Detailed mapping of these plumes points to only 9-10 active <span class="hlt">sites</span> in 850 km, however, yielding a <span class="hlt">site</span> frequency Fs, <span class="hlt">sites</span>/100 km of ridge length, of 1.1-1.2. Plumes detected along the SWIR are considerably less extensive for two reasons: an apparent paucity of active <span class="hlt">vent</span> fields on volcanic highs and a normal deep-ocean density gradient that prevents extended plume rise. Along a western SWIR section (10°-23°E) we identify 3-8 <span class="hlt">sites</span>, so Fs = 0.3-0.8; along a previously surveyed 440 km section of the eastern SWIR (58°-66°E), 6 <span class="hlt">sites</span> yield Fs = 1.3. Plotting spreading rate (us) versus Fs, the ultraslow ridges and eight other ridge sections, spanning the global range of spreading rate, establish a robust linear trend (Fs = 0.98 + 0.015us), implying that the long-term heat supply is the first-order control on the global distribution of <span class="hlt">hydrothermal</span> activity. Normalizing Fs to the delivery rate of basaltic magma suggests that ultraslow ridges are several times more efficient than faster-spreading ridges in supporting active <span class="hlt">vent</span> fields. This increased efficiency could derive from some combination of three-dimensional magma focusing at volcanic centers, deep mining of heat from gabbroic intrusions and direct cooling of the upper mantle, and nonmagmatic heat supplied by exothermic serpentinization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFM.V11C..11M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.V11C..11M"><span id="translatedtitle">Biological nitrogen fixation in the subseafloor associated with mid-ocean-ridge <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>Mehta, M.; Butterfield, D. A.; Baross, J. A.</p> <p>2002-12-01</p> <p>Thermophilic and hyperthermophilic microorganisms that have been isolated from diffuse <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluid are assumed to reside within hot, anaerobic zones in the subseafloor. These microorganisms can be metabolically versatile or highly specialized, and utilize a variety of carbon and energy sources that are available in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluid. However, the nitrogen sources that support subseafloor microbial communities remain unknown. Chemical analyses indicate that nitrate and nitrite are depleted in diffuse <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids relative to deep seawater and are absent in reduced fluids above 30°C. Ammonium concentrations in low temperature <span class="hlt">vent</span> fluid are similar to the low concentrations in deep seawater, with the exception of sedimented <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems such as Guaymas Basin and the aberrant, unsedimented Endeavour Segment on the Juan de Fuca Ridge. The largest reservoir of nitrogen in the ocean is dissolved dinitrogen gas, which is abundant in deep seawater and slightly elevated in <span class="hlt">hydrothermal</span> fluids. Biological nitrogen fixation was first suggested as a potential source of nitrogen to <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystems based on the nitrogen isotope ratios of low trophic level <span class="hlt">vent</span> fauna, which are much lower than the nitrogen isotope ratios of deep sea organic nitrogen, ammonium and nitrate, but resemble those of deep-ocean dinitrogen gas and marine biota associated with nitrogen fixation. We have detected the genetic potential for nitrogen fixation by amplifying and sequencing one of the genes responsible for nitrogen fixation, nifH, from diffuse <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluid. The nifH genes present in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluid originate from a diverse nifH assemblage in the subseafloor as well as a phylogenetically distinct nifH cluster in deep seawater. While there was no major difference in the nifH populations between nitrogen-rich and nitrogen-poor diffuse <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, we will attempt to detect the expression of nifH in situ and in nitrogen-fixing isolates cultured from <span class="hlt">vent</span> fluids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.B12A0776L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.B12A0776L"><span id="translatedtitle">Chemistry of a serpentinization-controlled <span class="hlt">hydrothermal</span> system at the Lost City <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>Ludwig, K. A.; Kelley, D. S.; Butterfield, D. A.; Nelson, B. K.; Karson, J. A.</p> <p>2003-12-01</p> <p>The Lost City <span class="hlt">Hydrothermal</span> Field (LCHF), at 30° N near the Mid-Atlantic Ridge, is an off-axis, low temperature, high-pH, ultramafic-hosted <span class="hlt">vent</span> system. Within the field, carbonate chimneys tower up to 60 m above the seafloor, making them the tallest <span class="hlt">vent</span> structures known. The chemistry of the <span class="hlt">vent</span> structures and fluids at the LCHF is controlled by reactions between seawater and ultramafic rocks beneath the Atlantis massif. Mixing of warm alkaline <span class="hlt">vent</span> fluids with seawater causes precipitation of calcium carbonate and growth of the edifaces, which range from tall, graceful pinnacles to fragile flanges and colloform deposits. Geochemical and petrological analyses of the carbonate rocks reveal distinct differences between the active and extinct structures. Actively <span class="hlt">venting</span> chimneys and flanges are extremely porous, friable formations composed predominantly of aragonite and brucite. These structures provide important niches for well-developed microbial communities that thrive on and within the chimney walls. Some of the active chimneys may also contain the mineral ikaite, an unstable, hydrated form of calcium carbonate. TIMS and ICP-MS analyses of the carbonate chimneys show that the most active chimneys have low Sr isotope values and that they are low in trace metals (e.g., Mn, Ti, Pb). Active structures emit high-pH, low-Mg fluids at 40-90° C. The fluids also have low Sr values, indicating circulation of <span class="hlt">hydrothermal</span> solutions through the serpentinite bedrock beneath the field. In contrast to the active structures, extinct chimneys are less porous, are well lithified, and they are composed predominantly of calcite that yields Sr isotopes near seawater values. Prolonged lower temperature seawater-<span class="hlt">hydrothermal</span> fluid interaction within the chimneys results in the conversion of aragonite to calcite and in the enrichment of some trace metals (e.g., Mn, Ti, Co, Zn). It also promotes the incorporation of foraminifera within the outer, cemented walls of the carbonate structures. The Lost City system represents a novel natural laboratory for observing <span class="hlt">hydrothermal</span> and biological activity in a system controlled by moderate temperature serpentinization reactions. The LCHF is the only <span class="hlt">vent</span> field of its kind known to date; however, it is likely not unique along the global mid-ocean ridge spreading network.</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://www.ncbi.nlm.nih.gov/pubmed/26375668','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26375668"><span id="translatedtitle">Microbial diversity in deep-sea sediments from the Menez Gwen <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> system 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>Cerqueira, Teresa; Pinho, Diogo; Egas, Conceição; Froufe, Hugo; Altermark, Bjørn; Candeias, Carla; Santos, Ricardo S; Bettencourt, Raul</p> <p>2015-12-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> sediments are known to support remarkably diverse microbial consortia. Cultureindependent sequence-based technologies have extensively been used to disclose the associated microbial diversity as most of the microorganisms inhabiting these ecosystems remain uncultured. Here we provide the first description of the microbial community diversity found on sediments from Menez Gwen <span class="hlt">vent</span> system. We compared <span class="hlt">hydrothermally</span> influenced sediments, retrieved from an active <span class="hlt">vent</span> chimney at 812 m depth, with non-<span class="hlt">hydrothermally</span> influenced sediments, from a 1400 m depth bathyal plain. Considering the enriched methane and sulfur composition of Menez Gwen <span class="hlt">vent</span> fluids, and the sediment physicochemical properties in each sampled area, we hypothesized that the <span class="hlt">site</span>-associated microbes would be different. To address this question, taxonomic profiles of bacterial, archaeal and micro-eukaryotic representatives were studied by rRNA gene tag pyrosequencing. Communities were shown to be significantly different and segregated by sediment geographical area. Specific mesophilic, thermophilic and hyperthermophilic archaeal (e.g., Archaeoglobus, ANME-1) and bacterial (e.g., Caldithrix, Thermodesulfobacteria) taxa were highly abundant near the <span class="hlt">vent</span> chimney. In contrast, bathyal-associated members affiliated to more ubiquitous phylogroups from deep-ocean sediments (e.g., Thaumarchaeota MGI, Gamma- and Alphaproteobacteria). This study provides a broader picture of the biological diversity and microbial biogeography, and represents a preliminary approach to the microbial ecology associated with the deep-sea sediments from the Menez Gwen <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field. PMID:26375668</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23750565','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23750565"><span id="translatedtitle">Diversity and distributional patterns of ciliates in Guaymas Basin <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>Coyne, Kathryn J; Countway, Peter D; Pilditch, Conrad A; Lee, Charles K; Caron, David A; Cary, Stephen C</p> <p>2013-01-01</p> <p>Little is known about protists at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. The <span class="hlt">vent</span> <span class="hlt">sites</span> at Guaymas Basin in the Gulf of California are characterized by dense mats of filamentous pigmented or nonpigmented Beggiatoa that serve as markers of subsurface thermochemical gradients. We constructed 18S rRNA libraries to investigate ciliate assemblages in Beggiatoa mats and from bare sediments at the Guaymas <span class="hlt">vent</span> <span class="hlt">site</span>. Results indicated a high diversity of ciliates, with 156 operational taxonomic units identified in 548 sequences. Comparison between mat environments demonstrated that ciliate and bacterial assemblages from pigmented mats, nonpigmented mats, and bare sediments were significantly different and highly correlated with bacterial assemblages. Neither bacterial nor ciliate assemblages were correlated with environmental factors. The most abundant ciliates at Guaymas were more likely to be represented in clone libraries from other <span class="hlt">hydrothermal</span>, deep-sea, and/or anoxic or microaerophilic environments, supporting the hypothesis that these ciliate species are broadly distributed. The orange mat environment included a higher proportion of ciliate sequences that were more similar to those from other environmental studies than to cultured ciliate species, whereas clone libraries from bare sediments included sequences that were the most highly divergent from all other sequences and may represent species that are endemic to Guaymas. PMID:23750565</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012DSRI...62...10K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012DSRI...62...10K"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> community zonation along environmental gradients at the Lau back-arc 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>Kim, Stacy; Hammerstrom, Kamille</p> <p>2012-04-01</p> <p>The Lau back-arc spreading center exhibits gradients in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> habitat characteristics from north to south. Biological zonation within a few meters of <span class="hlt">vents</span> has been described as temperature driven. We constructed georeferenced photomosaics of the seafloor out to tens of meters beyond <span class="hlt">vents</span> to describe peripheral zonation and explore correlations between environmental conditions and the biological community. Cluster analysis separated northern <span class="hlt">sites</span> from southern <span class="hlt">sites</span>, corresponding to a break in substrate from basalt in the north to andesite in the south. Northern <span class="hlt">sites</span> were dominated by anemones, and southern by sponges. A previous suggestion that dominants may be dependent on friability of the substrate was not supported; when visually distinguishable, individual species within taxa showed different patterns. Northern <span class="hlt">sites</span> hosted proportionally more suspension feeding species. Sulfide that can support microbial food sources is at higher concentrations at these <span class="hlt">sites</span>, though bathymetry that may enhance bottom currents is less rugged. Northern <span class="hlt">sites</span> had higher diversity that may result from the overall northwards flow, which would generally permit easier dispersal downcurrent, though we observed no difference in dispersal strategies at different <span class="hlt">sites</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20623654','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20623654"><span id="translatedtitle">Sperm ultrastructure of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> octopod Vulcanoctopus hydrothermalis.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Roura, A; Guerra, A; Gonzlez, A F; Pascual, S</p> <p>2010-08-01</p> <p>Sperm ultrastructure of the deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> octopod Vulcanoctopus hydrothermalis has been carried out by transmission electron microscopy. Spermatozoa of this species have the shortest head observed so far in octopodids. The acrosome possesses a helix with six gyres. The rod-shaped nucleus is short and wide in relation with other octopodids. Noteworthy features along the nucleus are the regularly disposed dense bands of cytoplasm, which have not been observed before in octopodids. The nuclear fossa is very short and wavy. Mitochondrial sheath has 10 elongated mitochondria running parallel to the axoneme-coarse fibers complex. Sperm morphology of V. hydrothermalis resembles that of Enteroctopus dofleini, suggesting a close phylogenetic relationship. PMID:20623654</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23002089','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23002089"><span id="translatedtitle">When did decapods invade <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>? Clues from the Western Pacific and Indian Oceans.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Jin-Shu; Lu, Bo; Chen, Dian-Fu; Yu, Yan-Qin; Yang, Fan; Nagasawa, Hiromichi; Tsuchida, Shinji; Fujiwara, Yoshihiro; Yang, Wei-Jun</p> <p>2013-02-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> are typically located in midocean ridges and back-arc basins and are usually generated by the movement of tectonic plates. Life thrives in these environments despite the extreme conditions. In addition to chemoautotrophic bacteria, decapod crustaceans are dominant in many of the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> discovered to date. Contrary to the hypothesis that these species are remnants of relic fauna, increasing evidence supports the notion that <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> decapods have diversified in more recent times with previous research attributing the origin of alvinocarid shrimps to the Miocene. This study investigated seven representative decapod species from four <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> throughout the Western Pacific and Indian Oceans. A partitioned mix-model phylogenomic analysis of mitochondrial DNA produced a consistent phylogenetic topology of these <span class="hlt">vent</span>-endemic species. Additionally, molecular dating analysis calibrated using multiple fossils suggested that both bythograeid crabs and alvinocarid shrimps originated in the late Mesozoic and early Cenozoic. Although of limited sampling, our estimates support the extinction/repopulation hypothesis, which postulates recent diversification times for most <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> species due to their mass extinction by global deep-water anoxic/dysoxic events during the Late Cretaceous and Early Tertiary. The continental-derived property of the West Pacific province is compatible with the possibility that <span class="hlt">vent</span> decapods diversified from ancestors from shallow-water regions such as cold seeps. Our results move us a step closer toward understanding the evolutionary origin of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> species and their distribution in the Western Pacific-Indian Ocean Region. PMID:23002089</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.T43D2704F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.T43D2704F"><span id="translatedtitle">Magnetic Structure of Backarc Spreading Axis with <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span>; the Southern Mariana Trough</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.; Mochizuki, N.; Honsho, C.; Szitkar, F.; Dyment, J.; Nakamura, K.</p> <p>2012-12-01</p> <p>Seafloor <span class="hlt">hydrothermal</span> systems are important in relation to global heat and chemical fluxes as well as habitat of microbial communities. The substantial variation of <span class="hlt">hydrothermal</span> systems in various tectonic settings has important implications for the magnetic structure of oceanic crust. It has been very difficult to detect the geophysical signature of <span class="hlt">hydrothermal</span> systems from sea-surface data because the small scale of <span class="hlt">hydrothermal</span> systems is below the limit of resolution. The advance of near-bottom survey methods using a submersible, deep-tow, ROV and AUV has made possible high-resolution geophysical mapping around <span class="hlt">hydrothermal</span> areas. Near-bottom magnetic surveys can provide direct information on the magnetization of the shallower oceanic crust, implying <span class="hlt">hydrothermal</span> alteration both in active and fossil <span class="hlt">vent</span> <span class="hlt">sites</span>. Near-bottom three component magnetic measurements on submersible Shinkai 6500 were carried out at <span class="hlt">hydrothermal</span> fields in the Southern Mariana Trough, a slow spreading backarc basin. Fourteen dive surveys were conducted during cruises YK11-10 and YK10-11. We investigated the magnetic structure of four <span class="hlt">hydrothermal</span> systems located at on- and off-axis to clarify how the geophysical and geological setting controls the fluid circulation at small scale. Recent researches at slow spreading ridges showed a relationship between crustal magnetic structure and host rock around <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> (e.g. Tivey and Dyment, 2010), but no observation at backarc spreading axis has been reported so far. We carefully corrected the effects of induced and permanent magnetizations of the submersible by applying the method of Isezaki [1986] with dumped least-square method (Honsho et al., 2009). After subtracting the IGRF from the corrected observed data, we obtained geomagnetic vector anomalies in geographical coordinate. For three transects of the axis, we applied three methods; 2D inversion technique (Parker and Huestis, 1972), 2D forward modeling technique (Honsho et al, 2009) and 2D direct inversion technique (Hussenoeder et al., 1995). Transect 1 (T1) and transect 2 (T2) are parallel and very closely located, crossing the neo-volcanic zone near an on-axis <span class="hlt">hydrothermal</span> <span class="hlt">site</span> (Snail <span class="hlt">Site</span>) at different altitude, 2m and 30m. Transect 3 (T3) also crosses a large on-axis volcanic mound on which another <span class="hlt">hydrothermal</span> <span class="hlt">site</span> (Yamanaka <span class="hlt">Site</span>) is located. The equivalent magnetization calculated on T1 and T2 are similar although their resolutions are different. The one along T3 shows high values around the large volcanic mound and an area of low magnetization near a <span class="hlt">hydrothermal</span> field recognized from high-resolution bathymetry (Yoshikawa et al., 2012). A similar reduction of magnetization above <span class="hlt">hydrothermal</span> fields was also reported in basalt-hosted <span class="hlt">sites</span> along the Mid Atlantic Ridge. The detailed bathymetry (2m grid) collected by AUV Urashima in the study area allows us to investigate the effect of three dimensional structure. We estimate magnetization using a new technique based on 3D forward modeling (Szitkar et al, this meeting). A preliminary result shows a similar but more detailed magnetic structure around the Yamanaka <span class="hlt">Site</span> compared to results of the 2D methods.</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/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://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://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/2004AGUFM.V41B1391O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.V41B1391O"><span id="translatedtitle">In Situ Observations of Dissolved Manganese in <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Plumes at Mariana Trough.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Okamura, K.; Yanai, K.; Sohrin, Y.; Ishibashi, J.; Watanabe, M.; Ura, T.</p> <p>2004-12-01</p> <p>We studied for <span class="hlt">hydrothermal</span> plumes in Mariana Trough by using in situ Mn-Fe analyzers (GAMOS-II). GAMOS-II (Geochemical Anomalies MOnitoring system) is an in-situ chemical analyzer used to detect manganese and/or iron anomalies in neutrally buoyant plumes and to map distributions in bottom seawater over <span class="hlt">vent</span> fields. During TN167 (ROV ROPOS / R/V Thomas G Thompson) cruise, GAMOS-II measurements were conducted for plume observation at the Yamanaka and Fryer <span class="hlt">sites</span>. GAMOS-II was attached on the sampling stage of the ROPOS at dive #'777. ROPOS arrived at the bottom at 0:50, and left the bottom at 10:55. Active manganese and temperature anomalies were detected around 2:00 - 5:00 and 7:00 - 11:00, when the ROPOS passed through <span class="hlt">hydrothermally</span> active areas. The anomaly of temperature and manganese concentration was observed coincidentally, but the relation ship is not consistently proportional. Wide variation in Mn vs. temperature ratio implies diversity between geochemical flux and heat flux depending on the type of <span class="hlt">venting</span> in the <span class="hlt">hydrothermal</span> <span class="hlt">sites</span>. During KH-04-02 Leg2 (AUV r2D4 / R/V Hakuho-Maru) cruise, GAMOS-II measurements were also conducted for plume observation at NW ROTA #1 seamount. GAMOS-II was attached in the AUV r2D4 with CTD. During four successive dives, the fine structure of <span class="hlt">hydrothermal</span> plumes changed drastically, probably reflecting temporal variation of <span class="hlt">hydrothermal</span> activity. Continuous sampling by using GAMOS-II was also done successfully. We will also discuss about the data of this continuous sampling.</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.ncbi.nlm.nih.gov/pubmed/17684750','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17684750"><span id="translatedtitle">Shell nacre ultrastructure and depressurisation dissolution 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://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kadar, Eniko; Checa, Antonio G; Damasceno-Oliveira, Alfredo; Oliveira, Alfredo N D P; Machado, Jorge P</p> <p>2008-01-01</p> <p>This study describes the micro-morphological features of the shell nacre in the <span class="hlt">vent</span> mytilid Bathymodiolus azoricus collected along a bathymetric gradient of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> of the mid-Atlantic ridge (MAR). Pressure-dependent crystallisation patterns were detected in animals subjected to post-capture hydrostatic simulations. We provide evidence for the following: (1) shell micro morphology in B. azoricus is similar to that of several <span class="hlt">vent</span> and cold-seep species, but the prismatic shell layers may vary among bathymodiolids; (2) nacre micro-morphology of mussels from three <span class="hlt">vent</span> <span class="hlt">sites</span> of the MAR did not differ significantly; minor differences do not appear to be related to hydrostatic pressure, but rather to calcium ion availability; (3) decompression stress may cause drop off in pH of the pallial fluid that damages nascent crystals, and in a more advanced phase, the aragonite tablets as well as the continuous layer of mature nacre; and (4) adverse effects of decompression on calcium salt deposition in shells was diminished by re-pressurisation of specimens. The implications of the putative influence of hydrostatic pressure on biomineralisation processes in molluscs are discussed. PMID:17684750</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.V43F..06C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.V43F..06C"><span id="translatedtitle">The Geologic Setting of <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> at Mariana Arc Submarine Volcanoes: High-Resolution Bathymetry and ROV Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chadwick, W. W.; Embley, R. W.; de Ronde, C. E.; Stern, R. J.; Hein, J.; Merle, S.; Ristau, S.</p> <p>2004-12-01</p> <p>Remotely operated vehicle (ROV) dives were made at 7 submarine volcanoes between 14-23 N in the Mariana Arc in April 2004 with the ROPOS ROV. Six of these volcanoes were known to be <span class="hlt">hydrothermally</span> active from CTD data collected during a previous expedition in March 2003: NW Rota-1, E Diamante, NW Eifuku, Daikoku, Kasuga-2, and Maug, a partly submerged caldera. The physical setting of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> varies widely from volcano to volcano. High-resolution bathymetric surveys of the summits of NW Rota-1 and NW Eifuku volcanoes were conducted with an Imagenex scanning sonar mounted on ROPOS. Near bottom observations during ROPOS dives were recorded with digital video and a digital still camera and the dives were navigated acoustically from the R/V Thompson using an ultra-short baseline system. The mapping and dive observations reveal the following: (1) The summits of some volcanoes have pervasive diffuse <span class="hlt">venting</span> (NW Rota-1, Daikoku, NW Eifuku) suggesting that <span class="hlt">hydrothermal</span> fluids are able to circulate freely within a permeable edifice. At other volcanoes, the <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> is more localized (Kasuga-2, Maug, E Diamante), suggesting more restricted permeability pathways. (2) Some volcanoes have both focused <span class="hlt">venting</span> at depth and diffuse <span class="hlt">venting</span> near the summit (E Diamante, NW Eifuku). Where the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are focused, fluid flow appears to be localized by massive lava outcrops that form steep cliffs and ridges, or by subsurface structures such as dikes. High-temperature (240 C) <span class="hlt">venting</span> was only observed at E Diamante volcano, where the "Black Forest" <span class="hlt">vent</span> field is located on the side of a constructional cone near the middle of E Diamante caldera at a depth of 350 m. On the side of an adjacent shallower cone, the <span class="hlt">venting</span> style changed to diffuse discharge and it extended all the way up into the photic zone (167 m). At NW Eifuku, the pattern of both deep-focused and shallow-diffuse <span class="hlt">venting</span> is repeated. "Champagne <span class="hlt">vent</span>" is located at 1607 m, ~150 m below the summit, and is characterized by focused flow of CO2-rich fluids, whereas the summit has extensive areas of diffuse <span class="hlt">venting</span> and is covered with thick bacterial mats. (3) Some of the most remarkable <span class="hlt">vent</span> <span class="hlt">sites</span> are deep, narrow volcanic craters at NW Rota-1 and Daikoku volcanoes. The crater at NW Rota-1 volcano (named "Brimstone Pit") is 15-m wide, 20-m deep, funnel shaped, and was actively erupting ash, lapilli, and molten sulfur. The rim of Brimstone Pit is composed of welded spatter and is located at 550 m depth, about 30 m below the summit. Other diffuse <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> at NW Rota-1 are located along the rocky summit ridge. At Daikoku volcano, an extraordinary crater emitting cloudy <span class="hlt">hydrothermal</span> fluid was found at 375 m depth on the north shoulder of the volcano, about 75 m below the summit. This crater was at least 135 m deep and had a remarkably cylindrical cross-section with a diameter of ~50 m. ROPOS descended 75 m into the crater and was still at least 60 m above the bottom, according to the altimeter, when we were forced to cease operations due to weather. In addition, diffuse <span class="hlt">hydrothermal</span> fluids seep from large areas of the summit and upper slopes of Daikoku.</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/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 (δ13CTOC ~ -20‰, δ13CDIC ~ +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> </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://www.osti.gov/scitech/servlets/purl/1237624','SCIGOV-DOEDE'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1237624"><span id="translatedtitle">Google Earth locations of USA and seafloor <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> with associated rare earth element data</span></a></p> <p><a target="_blank" href="http://www.osti.gov/dataexplorer">DOE Data Explorer</a></p> <p>Andrew Fowler</p> <p>2016-02-10</p> <p>Google Earth .kmz files that contain the locations of geothermal wells and thermal springs in the USA, and seafloor <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> that have associated rare earth element data. The file does not contain the actual data, the actual data is available through the GDR website in two tier 3 data sets entitled "Compilation of Rare Earth Element Analyses from US Geothermal Fields and Mid Ocean Ridge (MOR) <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span>" and "Rare earth element content of thermal fluids from Surprise Valley, California"</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> <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://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. δ13C 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 δ13C 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 δ13C occurred in Kiwa sp. (−19.0‰ to −10.5‰), similar to that of the epibionts sampled from their ventral setae. Kiwa sp. δ13C 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 δ13C and δ34S 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://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4069388','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4069388"><span id="translatedtitle">Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> Epsilonproteobacteria encode a conserved and widespread nitrate reduction pathway (Nap)</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Vetriani, Costantino; Voordeckers, James W; Crespo-Medina, Melitza; O'Brien, Charles E; Giovannelli, Donato; Lutz, Richard A</p> <p>2014-01-01</p> <p>Despite the frequent isolation of nitrate-respiring Epsilonproteobacteria from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, the genes coding for the nitrate reduction pathway in these organisms have not been investigated in depth. In this study we have shown that the gene cluster coding for the periplasmic nitrate reductase complex (nap) is highly conserved in chemolithoautotrophic, nitrate-reducing Epsilonproteobacteria from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Furthermore, we have shown that the napA gene is expressed in pure cultures of <span class="hlt">vent</span> Epsilonproteobacteria and it is highly conserved in microbial communities collected from deep-sea <span class="hlt">vents</span> characterized by different temperature and redox regimes. The diversity of nitrate-reducing Epsilonproteobacteria was found to be higher in moderate temperature, diffuse flow <span class="hlt">vents</span> than in high temperature black smokers or in low temperatures, substrate-associated communities. As NapA has a high affinity for nitrate compared with the membrane-bound enzyme, its occurrence in <span class="hlt">vent</span> Epsilonproteobacteria may represent an adaptation of these organisms to the low nitrate concentrations typically found in <span class="hlt">vent</span> fluids. Taken together, our findings indicate that nitrate reduction is widespread in <span class="hlt">vent</span> Epsilonproteobacteria and provide insight on alternative energy metabolism in <span class="hlt">vent</span> microorganisms. The occurrence of the nap cluster in <span class="hlt">vent</span>, commensal and pathogenic Epsilonproteobacteria suggests that the ability of these bacteria to respire nitrate is important in habitats as different as the deep-sea <span class="hlt">vents</span> and the human body. PMID:24430487</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.4342K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.4342K"><span id="translatedtitle">Heat and Volume Fluxes at the Turtle Pits <span class="hlt">Vent</span> <span class="hlt">Site</span>, southern 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>Köhler, Janna; Walter, Maren; Mertens, Christian; Sültenfuß, Jürgen; Rhein, Monika</p> <p>2010-05-01</p> <p>The Turtle Pits <span class="hlt">vent</span> <span class="hlt">site</span> consists of eight known high temperature <span class="hlt">vents</span> and several diffuse <span class="hlt">vent</span> <span class="hlt">sites</span> which are distributed over three <span class="hlt">hydrothermal</span> fields: Turtle Pits, Comfortless Cove, and Red Lion. These <span class="hlt">vent</span> fields are located in a north-south orientated rift valley at the Mid-Atlantic Ridge (MAR) near 5°S. The total volume and heat emissions of the entire Turtle Pits <span class="hlt">site</span> have been calculated with three different approaches using data collected during a Meteor cruise in May 2006 and a L'Atalante cruise in January 2008. The data sets consist of vertical profiles and towed transects of temperature, salinity, and turbidity, as well as direct velocity measurements with a lowered acoustic Doppler current profiler (LADCP) and water samples for Helium isotope analysis. <span class="hlt">Vent</span> fluid samples for noble gas analysis where taken with ROVs. Since the <span class="hlt">vent</span> fluid is highly enriched in primordial 3He this noble gas can be used as a conservative tracer for <span class="hlt">vent</span> fluid. The geographical setting of the <span class="hlt">vent</span> <span class="hlt">site</span> confines the particle plume to the rift valley since the depth of the valley exceeds the rise height of the plume. Therefore the fluxes of heat and volume can be estimated from the horizontal helium transport in the valley in combination with a mean 3He endmember concentration determined from the water samples taken with the ROVs. The comparison of the 3He concentrations measured south of the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> with the 3He signal north of the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> suggests a rather strong northward flow. This is confirmed by the tide corrected velocities observed with the LADCP during the Meteor cruise. The northward volume transport has been calculated using the local bathymetry and tide corrected velocities from the Meteor cruise. In combination with the 3He concentrations and the average 3He endmember concentration a flux of 1000 l/s is estimated, which corresponds to a heat flux of 1400 MW. The measured temperature anomalies within the plume combined with the known background stratification and the mean flow velocity within the valley yield an estimate of the total flux of the <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> which is significantly lower. Similar results have been calculated using the rise height of the particle plume estimated from the measured temperature anomalies in combination with the background stratification. In contrast to the flux calculated from the 3He concentrations the fluxes calculated from the temperature anomaly and the plume rise height only take the emissions from hot <span class="hlt">vents</span> into account and exclude emissions from diffuse <span class="hlt">vent</span> <span class="hlt">sites</span>.</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.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=383022','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=383022"><span id="translatedtitle">Sulfide Ameliorates Metal Toxicity for Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Archaea†</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Edgcomb, Virginia P.; Molyneaux, Stephen J.; Saito, Mak A.; Lloyd, Karen; Böer, Simone; Wirsen, Carl O.; Atkins, Michael S.; Teske, Andreas</p> <p>2004-01-01</p> <p>The chemical stress factors for microbial life at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> include high concentrations of heavy metals and sulfide. Three hyperthermophilic <span class="hlt">vent</span> archaea, the sulfur-reducing heterotrophs Thermococcus fumicolans and Pyrococcus strain GB-D and the chemolithoautotrophic methanogen Methanocaldococcus jannaschii, were tested for survival tolerance to heavy metals (Zn, Co, and Cu) and sulfide. The sulfide addition consistently ameliorated the high toxicity of free metal cations by the formation of dissolved metal-sulfide complexes as well as solid precipitates. Thus, chemical speciation of heavy metals with sulfide allows <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> archaea to tolerate otherwise toxic metal concentrations in their natural environment. PMID:15066859</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://www.ncbi.nlm.nih.gov/pubmed/23720658','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23720658"><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=pubmed">PubMed</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://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://adsabs.harvard.edu/abs/2005AGUFM.B31A0955A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.B31A0955A"><span id="translatedtitle">Microbial arsenic oxidation in a shallow marine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Amend, J. P.; Meyer-Dombard, D. R.; Pichler, T.; Price, R.; Herndon, E.; Hsia, N.</p> <p>2005-12-01</p> <p>The toxic effects of arsenic are well documented, but this Group V element can also serve as an energy source to a diverse group of microorganisms. Most of the attention has been on arsenate (AsV) reduction, but the focus is shifting to include arsenite (AsIII) oxidation and subsequent immobilization through coprecipitation with iron (oxy)hydroxides. The shallow marine <span class="hlt">hydrothermal</span> fluids near Ambitle Island, Papua New Guinea are characterized by arsenite concentrations of up to 1,000 μg/L. Directly proximal to the <span class="hlt">vent</span> orifices, arsenate coprecipitates with 2-line ferrihydrite, coating rocks and corals in red and green biofilms up to 1 cm thick. DNA extracted from these coatings was amplified with archaeal- and bacterial-specific primers, and the 16S rRNA gene was sequenced. Both biofilm samples revealed archaeal communities exclusively composed of uncultured Crenarchaea. The bacterial members are primarily gamma Proteobacteria and Planctomycetes in the red biofilm, but 60% of the community in the green biofilm affiliate with the alpha Proteobacteria and candidate group OP11; there is minimal overlap in bacterial phylotypes between the two coatings. Slurries from these coatings were also used to inoculate geochemically designed growth media supplemented with various redox couples, including aerobic and anaerobic As(III) oxidation. On a medium targeting anaerobic, chemolithoautotrophic arsenic oxidation coupled to ferric iron reduction at 50 °C, predominantly rod-shaped organisms (~5×105 cells/ml) were enriched. In contrast, on an aerobic arsenic oxidation medium, coccoid-shaped organisms (~3×106 cells/ml) were enriched. The respective thermophilic microbial communities may be taking advantage of overall metabolisms represented by H3AsO3(aq) + 2FeOOH(s) + 3H+ = H2AsO4- + 2Fe2+ + 3H2O (1) and H3AsO3(aq) + 1/2O2(aq) = H2AsO4- + H+. (2) To date, no arsenite oxidizers are known to use ferric iron as a terminal electron acceptor (reaction 1). However, this environment, where arsenite-laden <span class="hlt">vent</span> waters flow past mineral surfaces that can serve both as physical template and as oxidant, may be ideal for these putative organisms. On the other hand, a number of aerobic arsenite oxidizers have been described, especially among the bacteria, and reaction (2) is likely to support a microbial community involved in the oxidation and subsequent precipitation of arsenic.</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://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://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 δ34S values of primary consumers with distance from <span class="hlt">vent</span> sources, and variation in their δ13C 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://www.ncbi.nlm.nih.gov/pubmed/23144754','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23144754"><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=pubmed">PubMed</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 m(2) 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 δ(34)S values of primary consumers with distance from <span class="hlt">vent</span> sources, and variation in their δ(13)C 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://www.ncbi.nlm.nih.gov/pubmed/26849440','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26849440"><span id="translatedtitle">Community Structure of Macrobiota and Environmental Parameters in Shallow Water <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> off Kueishan Island, Taiwan.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chan, Benny Kwok Kan; Wang, Teng-Wei; Chen, Pin-Chen; Lin, Chia-Wei; Chan, Tin-Yam; Tsang, Ling Ming</p> <p>2016-01-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> represent a unique habitat in the marine ecosystem characterized with high water temperature and toxic acidic chemistry. <span class="hlt">Vents</span> are distributed at depths ranging from a few meters to several thousand meters. The biological communities of shallow-water <span class="hlt">vents</span> have, however, been insufficiently studied in most biogeographic areas. We attempted to characterize the macrofauna and macroflora community inhabiting the shallow-water <span class="hlt">vents</span> off Kueishan Island, Taiwan, to identify the main abiotic factors shaping the community structure and the species distribution. We determined that positively buoyant <span class="hlt">vent</span> fluid exhibits a more pronounced negative impact to species on the surface water than on the bottom layer. Species richness increased with horizontal distance from the <span class="hlt">vent</span>, and continuing for a distance of 2000 m, indicating that the <span class="hlt">vent</span> fluid may exert a negative impact over several kilometers. The community structure off Kueishan Island displayed numerous transitions along the horizontal gradient, which were broadly congruent with changes in environmental conditions. Combination of variation in Ca2+, Cl-, temperature, pH and depth were revealed to show the strongest correlation with the change in benthic community structure, suggesting multiple factors of <span class="hlt">vent</span> fluid were influencing the associated fauna. Only the <span class="hlt">vent</span> crabs of Kueishan Island may have an obligated relationship with <span class="hlt">vents</span> and inhabit the <span class="hlt">vent</span> mouths because other fauna found nearby are opportunistic taxa that are more tolerant to acidic and toxic environments. PMID:26849440</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4744018','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4744018"><span id="translatedtitle">Community Structure of Macrobiota and Environmental Parameters in Shallow Water <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> off Kueishan Island, Taiwan</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Chan, Benny Kwok Kan; Wang, Teng-Wei; Chen, Pin-Chen; Lin, Chia-Wei; Chan, Tin-Yam; Tsang, Ling Ming</p> <p>2016-01-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> represent a unique habitat in the marine ecosystem characterized with high water temperature and toxic acidic chemistry. <span class="hlt">Vents</span> are distributed at depths ranging from a few meters to several thousand meters. The biological communities of shallow-water <span class="hlt">vents</span> have, however, been insufficiently studied in most biogeographic areas. We attempted to characterize the macrofauna and macroflora community inhabiting the shallow-water <span class="hlt">vents</span> off Kueishan Island, Taiwan, to identify the main abiotic factors shaping the community structure and the species distribution. We determined that positively buoyant <span class="hlt">vent</span> fluid exhibits a more pronounced negative impact to species on the surface water than on the bottom layer. Species richness increased with horizontal distance from the <span class="hlt">vent</span>, and continuing for a distance of 2000 m, indicating that the <span class="hlt">vent</span> fluid may exert a negative impact over several kilometers. The community structure off Kueishan Island displayed numerous transitions along the horizontal gradient, which were broadly congruent with changes in environmental conditions. Combination of variation in Ca2+, Cl-, temperature, pH and depth were revealed to show the strongest correlation with the change in benthic community structure, suggesting multiple factors of <span class="hlt">vent</span> fluid were influencing the associated fauna. Only the <span class="hlt">vent</span> crabs of Kueishan Island may have an obligated relationship with <span class="hlt">vents</span> and inhabit the <span class="hlt">vent</span> mouths because other fauna found nearby are opportunistic taxa that are more tolerant to acidic and toxic environments. PMID:26849440</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> </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://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1460697','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1460697"><span id="translatedtitle">Genetic diversity of archaea in 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=pmc">PubMed Central</a></p> <p>Takai, K; Horikoshi, K</p> <p>1999-01-01</p> <p>Molecular phylogenetic analysis of naturally occurring archaeal communities in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments was carried out by PCR-mediated small subunit rRNA gene (SSU rDNA) sequencing. As determined through partial sequencing of rDNA clones amplified with archaea-specific primers, the archaeal populations in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments showed a great genetic diversity, and most members of these populations appeared to be uncultivated and unidentified organisms. In the phylogenetic analysis, a number of rDNA sequences obtained from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> were placed in deep lineages of the crenarchaeotic phylum prior to the divergence of cultivated thermophilic members of the crenarchaeota or between thermophilic members of the euryarchaeota and members of the methanogen-halophile clade. Whole cell in situ hybridization analysis suggested that some microorganisms of novel phylotypes predicted by molecular phylogenetic analysis were likely present in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments. These findings expand our view of the genetic diversity of archaea in deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environments and of the phylogenetic organization of archaea. PMID:10430559</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1987DSRA...34..379B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1987DSRA...34..379B"><span id="translatedtitle">Benthopelagic macrozooplankton communities at and near deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the eastern Pacific ocean and the Gulf of California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berg, Carl J.; Van Dover, Cindy Lee</p> <p>1987-03-01</p> <p>Benthopelagic zooplankton communities at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on the East Pacific Rise and in Guaymas Basin are enriched in terms of both biomass and abundance with respect to non-<span class="hlt">vent</span> areas, but depleted relative to biomass of surface zooplankton communities. Larval and juvenile stages of many benthic species, including Calyptogena spp., Bathymodiolus thermophilus, Nuculana sp., two undescribed species of limpets, Dahlella caldariensis, Bythograea sp., Munidopsis sp., epicaridean isopods, and lysianassid amphipods, were collected in the water column 1-5 m above <span class="hlt">vent</span> areas. Since much of the zooplankton community is derived from the benthic community, macrozooplankton abundance and composition differ among <span class="hlt">vent</span> <span class="hlt">sites</span> in accordance with the nature and extent of development of the benthic community and depend, ultimately, on the history of <span class="hlt">hydrothermal</span> activity at each <span class="hlt">site</span>.</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/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 222C 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://adsabs.harvard.edu/abs/2013GGG....14.4170W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GGG....14.4170W"><span id="translatedtitle">Moytirra: Discovery of the first known deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field on the slow-spreading Mid-Atlantic Ridge north of the Azores</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wheeler, A. J.; Murton, B.; Copley, J.; Lim, A.; Carlsson, J.; Collins, P.; Dorschel, B.; Green, D.; Judge, M.; Nye, V.; Benzie, J.; Antoniacomi, A.; Coughlan, M.; Morris, K.</p> <p>2013-10-01</p> <p>Geological, biological, morphological, and hydrochemical data are presented for the newly discovered Moytirra <span class="hlt">vent</span> field at 45oN. This is the only high temperature <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> known between the Azores and Iceland, in the North Atlantic and is located on a slow to ultraslow-spreading mid-ocean ridge uniquely situated on the 300 m high fault scarp of the eastern axial wall, 3.5 km from the axial volcanic ridge crest. Furthermore, the Moytirra <span class="hlt">vent</span> field is, unusually for tectonically controlled <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> systems, basalt hosted and perched midway up on the median valley wall and presumably heated by an off-axis magma chamber. The Moytirra <span class="hlt">vent</span> field consists of an alignment of four <span class="hlt">sites</span> of <span class="hlt">venting</span>, three actively emitting "black smoke," producing a complex of chimneys and beehive diffusers. The largest chimney is 18 m tall and vigorously <span class="hlt">venting</span>. The <span class="hlt">vent</span> fauna described here are the only ones documented for the North Atlantic (Azores to Reykjanes Ridge) and significantly expands our knowledge of North Atlantic biodiversity. The surfaces of the <span class="hlt">vent</span> chimneys are occupied by aggregations of gastropods (Peltospira sp.) and populations of alvinocaridid shrimp (Mirocaris sp. with Rimicaris sp. also present). Other fauna present include bythograeid crabs (Segonzacia sp.) and zoarcid fish (Pachycara sp.), but bathymodiolin mussels and actinostolid anemones were not observed in the <span class="hlt">vent</span> field. The discovery of the Moytirra <span class="hlt">vent</span> field therefore expands the known latitudinal distributions of several <span class="hlt">vent</span>-endemic genera in the north Atlantic, and reveals faunal affinities with <span class="hlt">vents</span> south of the Azores rather than north of Iceland.</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://www.ncbi.nlm.nih.gov/pubmed/26805789','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26805789"><span id="translatedtitle">An Unusual Stress Metabolite from a <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Fungus Aspergillus sp. WU 243 Induced by Cobalt.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ding, Chihong; Wu, Xiaodan; Auckloo, Bibi Nazia; Chen, Chen-Tung Arthur; Ye, Ying; Wang, Kuiwu; Wu, Bin</p> <p>2016-01-01</p> <p>A novel hybrid polyketide-terpenoid, aspergstressin (1), possessing a unique fused polycyclic structure, was induced from culture broth of strain Aspergillus sp. WU 243 by cobalt ion stimulation. The strain was isolated from the digestive gland of Xenograpsus testudinatus, a unique type of crab which dwells in the Kueishantao <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> off Taiwan. The chemical structure and relative configuration of the stress metabolite were established by spectroscopic means. Aspergillus sp. WU 243 produced aspergstressin (1) only under cobalt stressed culture conditions. The results show that stress-driven discovery of new natural products from <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fungi is an effective strategy to unveil the untapped reservoir of small molecules from species found in the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environment. PMID:26805789</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26784166','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26784166"><span id="translatedtitle">An Unusual Stress Metabolite from a <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Fungus Aspergillus sp. WU 243 Induced by Cobalt.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ding, Chihong; Wu, Xiaodan; Auckloo, Bibi Nazia; Chen, Chen-Tung Arthur; Ye, Ying; Wang, Kuiwu; Wu, Bin</p> <p>2016-01-01</p> <p>A novel hybrid polyketide-terpenoid, aspergstressin (1), possessing a unique fused polycyclic structure, was induced from culture broth of strain Aspergillus sp. WU 243 by cobalt ion stimulation. The strain was isolated from the digestive gland of Xenograpsus testudinatus, a unique type of crab which dwells in the Kueishantao <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> off Taiwan. The chemical structure and relative configuration of the stress metabolite were established by spectroscopic means. Aspergillus sp. WU 243 produced aspergstressin (1) only under cobalt stressed culture conditions. The results show that stress-driven discovery of new natural products from <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fungi is an effective strategy to unveil the untapped reservoir of small molecules from species found in the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environment. PMID:26784166</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26848647','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26848647"><span id="translatedtitle">An Unusual Stress Metabolite from a <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Fungus Aspergillus sp. WU 243 Induced by Cobalt.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ding, Chihong; Wu, Xiaodan; Auckloo, Bibi Nazia; Chen, Chen-Tung Arthur; Ye, Ying; Wang, Kuiwu; Wu, Bin</p> <p>2016-01-01</p> <p>A novel hybrid polyketide-terpenoid, aspergstressin (1), possessing a unique fused polycyclic structure, was induced from culture broth of strain Aspergillus sp. WU 243 by cobalt ion stimulation. The strain was isolated from the digestive gland of Xenograpsus testudinatus, a unique type of crab which dwells in the Kueishantao <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> off Taiwan. The chemical structure and relative configuration of the stress metabolite were established by spectroscopic means. Aspergillus sp. WU 243 produced aspergstressin (1) only under cobalt stressed culture conditions. The results show that stress-driven discovery of new natural products from <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fungi is an effective strategy to unveil the untapped reservoir of small molecules from species found in the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> environment. PMID:26848647</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>2016-01-01</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://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3497024','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3497024"><span id="translatedtitle">Ammonificins C and D, Hydroxyethylamine Chromene Derivatives from a Cultured Marine <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Bacterium, Thermovibrio ammonificans</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Andrianasolo, Eric H.; Haramaty, Liti; Rosario-Passapera, Richard; Vetriani, Costantino; Falkowski, Paul; White, Eileen; Lutz, Richard</p> <p>2012-01-01</p> <p>Chemical and biological investigation of the cultured marine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> bacterium, Thermovibrio ammonifican led to the isolation of two hydroxyethylamine chromene derivatives, ammonificins C and D. Their structures were elucidated using combination of NMR and mass spectrometry. Absolute stereochemistry was ascertained by comparison of experimental and calculated CD spectra. Biological evaluation and assessment were determined using the patented ApopScreen cell-based screen for apoptosis-induction. Ammonificins C and D induce apoptosis in micromolar concentrations. To our knowledge, this finding is the first report of chemical compounds that induce apoptosis from the cultured deep-sea marine organism, <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> bacterium, Thermovibrio ammonificans. PMID:23170085</p> </li> <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 δ13C axis, and showed a small variability in δ15N. 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 δ13C 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 δ13C, but did not increase the range in δ15N. 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://adsabs.harvard.edu/abs/2010GeoRL..3718303Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010GeoRL..3718303Z"><span id="translatedtitle">A reduced crustal magnetization zone near the first observed active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field on 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>Zhu, Jian; Lin, Jian; Chen, Yongshun J.; Tao, Chunhui; German, Christopher R.; Yoerger, Dana R.; Tivey, Maurice A.</p> <p>2010-09-01</p> <p>Inversion of near-bottom magnetic data reveals a well-defined low crustal magnetization zone (LMZ) near a local topographic high (37°47‧S, 49°39‧E) on the ultraslow-spreading Southwest Indian Ridge (SWIR). The magnetic data were collected by the autonomous underwater vehicle ABE on board R/V DaYangYiHao in February-March 2007. The first active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field observed on the SWIR is located in Area A within and adjacent to the LMZ at the local topographic high, implying that this LMZ may be the result of <span class="hlt">hydrothermal</span> alteration of magnetic minerals. The maximum reduction in crustal magnetization is 3 A/M. The spatial extent of the LMZ is estimated to be at least 6.7 × 104 m2, which is larger than that of the LMZs at the TAG <span class="hlt">vent</span> field on the Mid-Atlantic Ridge (MAR), as well as the Relict Field, Bastille, Dante-Grotto, and New Field <span class="hlt">vent-sites</span> on the Juan de Fuca Ridge (JdF). The calculated magnetic moment, i.e., the product of the spatial extent and amplitude of crustal magnetization reduction is at least -3 × 107 Am2 for the LMZ on the SWIR, while that for the TAG field on the MAR is -8 × 107 Am2 and that for the four individual <span class="hlt">vent</span> fields on the JdF range from -5 × 107 to -3 × 107 Am2. Together these results indicate that crustal demagnetization is a common feature of basalt-hosted <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields at mid-ocean ridges of all spreading rates. Furthermore, the crustal demagnetization of the Area A on the ultraslow-spreading SWIR is comparable in strength to that of the TAG area on the slow-spreading MAR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4688376','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4688376"><span id="translatedtitle">Genomic Reconstruction of an Uncultured <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Gammaproteobacterial Methanotroph (Family Methylothermaceae) Indicates Multiple Adaptations to Oxygen Limitation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Skennerton, Connor T.; Ward, Lewis M.; Michel, Alice; Metcalfe, Kyle; Valiente, Chanel; Mullin, Sean; Chan, Ken Y.; Gradinaru, Viviana; Orphan, Victoria J.</p> <p>2015-01-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vents</span> are an important contributor to marine biogeochemistry, producing large volumes of reduced fluids, gasses, and metals and housing unique, productive microbial and animal communities fueled by chemosynthesis. Methane is a common constituent of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluid and is frequently consumed at <span class="hlt">vent</span> <span class="hlt">sites</span> by methanotrophic bacteria that serve to control escape of this greenhouse gas into the atmosphere. Despite their ecological and geochemical importance, little is known about the ecophysiology of uncultured <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>-associated methanotrophic bacteria. Using metagenomic binning techniques, we recovered and analyzed a near-complete genome from a novel gammaproteobacterial methanotroph (B42) associated with a white smoker chimney in the Southern Lau basin. B42 was the dominant methanotroph in the community, at ∼80x coverage, with only four others detected in the metagenome, all on low coverage contigs (7x–12x). Phylogenetic placement of B42 showed it is a member of the Methylothermaceae, a family currently represented by only one sequenced genome. Metabolic inferences based on the presence of known pathways in the genome showed that B42 possesses a branched respiratory chain with A- and B-family heme copper oxidases, cytochrome bd oxidase and a partial denitrification pathway. These genes could allow B42 to respire over a wide range of oxygen concentrations within the highly dynamic <span class="hlt">vent</span> environment. Phylogenies of the denitrification genes revealed they are the result of separate horizontal gene transfer from other Proteobacteria and suggest that denitrification is a selective advantage in conditions where extremely low oxygen concentrations require all oxygen to be used for methane activation. PMID:26779119</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17841030','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17841030"><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.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</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. PMID:17841030</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/1984Sci...223..696S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984Sci...223..696S"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stein, Jeffrey L.</p> <p>1984-02-01</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/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> </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://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/2010DSRI...57..893C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010DSRI...57..893C"><span id="translatedtitle">Metal concentrations and metallothionein-like protein levels in deep-sea fishes captured near <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the Mid-Atlantic Ridge off Azores</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Company, R.; Felcia, H.; Serafim, A.; Almeida, A. J.; Biscoito, M.; Bebianno, M. J.</p> <p>2010-07-01</p> <p>The knowledge of metal contamination in deep-sea fishes living in the surroundings of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> is very scarce, along with the detoxification mechanisms that allow them to live near one of the most metal contaminated marine environments. Six deep-sea fish species, although not <span class="hlt">vent</span> endemic were collected near three Mid-Atlantic Ridge (MAR) <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> (Menez Gwen, Lucky Strike and Rainbow) and the gills, muscle and liver were selected for this study due to their importance in metal metabolism and storage. The concentrations of seven metals (Ag, Cd, Cr, Cu, Fe, Mn, and Ni) and a metal-related biomarker (metallothionein-like proteins-MTL) were assessed. Major differences in metal accumulation among fish species are related to their feeding habits and <span class="hlt">vent</span> <span class="hlt">site</span> of their capture. The liver and gills are in general the most important tissues for metal accumulation compared to the muscle, but tissue partitioning is very dependent on the fish species considered. Compared to other deep-sea fishes, fish capture in the vicinity of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> accumulates higher amounts of metals in general. However, MTL levels are not considerably different from what is found in commercial coastal fishes, and is poorly correlated with metal concentrations in the tissues. Therefore, MTL may not constitute one major detoxification system for deep-sea species living in the vicinity of three important MAR <span class="hlt">vent</span> <span class="hlt">sites</span>.</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/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., Frh-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://adsabs.harvard.edu/abs/2002AGUFM.T11C1261Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.T11C1261Y"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Plume Discovery and Survey with an Autonomous Underwater Vehicle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yoerger, D. R.; Collier, R.; Bradley, A. M.</p> <p>2002-12-01</p> <p>Autonomous Underwater Vehicles (AUVs) can detect and localize deep sea <span class="hlt">hydrothermal</span> plumes, and through the use of on-board intelligence have the potential to significantly improve the efficiency of plume search. The Autonomous Benthic Explorer has encountered both previously known and newly discovered <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in a variety of settings, including the East Pacific Rise (9N and 18S), the Juan de Fuca Ridge (47 54'N), several <span class="hlt">sites</span> along the Galapagos Rift (86-89W), and the Explorer Ridge (49 46'N). Typically, these plumes were encountered during sonar, video, and magnetic survey with the vehicle following the bottom terrain at heights from 6 to 40 meters, which in most cases placed the vehicle in the rising, buoyant portion of the plume. Typical instruments carried aboard the vehicle include CTD and optical backscatter, and ABE has also carried an acoustic current meter and a redox potential sensor. AUVs have great potential for efficiently locating <span class="hlt">vent</span> <span class="hlt">sites</span>. Unlike ship-towed CTDs, ROVs or manned submersibles, AUVs are uniquely suited to carrying out systematic, exhaustive search patterns. The addition of on-board intelligence, allowing the vehicle to alter its survey track based on sensor data, can greatly improve the yield from an AUV dive. For example, after detecting a plume, the vehicle could break off from its broad area survey and perform a fine grid, possibly at different heights off bottom. But before we can take advantage of this potential, we must understand how an AUV "sees" a plume, and how that perspective can change for different types of <span class="hlt">vents</span> in different settings. Our experience with ABE indicates that a successful autonomous plume survey must be based on a detailed understanding of plume physics. The plumes encountered by ABE in these surveys varied widely in terms of the magnitude of their fluid and thermal output, topographic setting, and ambient currents. The AUV-based observations of these plumes also varied widely, and these observations shed considerable light on the use of AUVs to autonomously detect and localize plumes. The Main Endeavor plumes were surveyed at a height of 70 meters off bottom and showed temperature anomalies up to 500 millidegrees, intense optical backscatter signals, and vertical velocities up to 25 cm/s. These velocities were sufficiently strong that they could be measured with a current meter carried on the vehicle or inferred through their effect on the vertical dynamics of the vehicle. At another extreme, at the Galapagos Rift, ABE surveyed a plume (ALR/3791<span class="hlt">Vent</span>) with temperature anomalies as small as 20 millidegrees, and no optical backscatter signal or discernable vertical velocity at a height of 40 meters. This smaller plume was ground-truthed by observations from the deep submersible Alvin. Finally, ABE surveyed the Calyfield on the Galapagos Rift shortly after its discovery by Alvin and observed little or no anomaly. As Calyfield is certainly more vigorous than the ALR/3791 <span class="hlt">vent</span>, the lack of a discernable signature while surveying in the same manner that located the ALR/3791<span class="hlt">vent</span> is noteworthy. This is most likely due to the complex hydrographic setting of the shallower Calyfield environment, including strong and variable tidal currents over abrupt topography and the presence of multiple water masses. These results will be compared to other plume prospecting techniques applied in the Galapagos including classical CTD tow-yo's and a CTD-instrumented towed camera sled.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMOS22B..05D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS22B..05D"><span id="translatedtitle">Microbial geochemistry in rising plumes of two <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> at 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>Dick, G.; Breier, J. A.; Toner, B. M.; Sheik, C.; Cron, B. R.; Li, M.; Reed, D. C.; Anantharaman, K.; Baker, B. J.; Jain, S.; Klausmeier, C. A.; Jiang, H.; German, C. R.; Seewald, J.; Sylva, S. P.; McDermott, J. M.; Bennett, S. A.</p> <p>2012-12-01</p> <p>Slow and ultraslow spreading ridges comprise ~50% of the global ridge-axis length and are thus relevant to the impact of <span class="hlt">hydrothermal</span> activity on global ocean biogeochemistry. These ridges host ultramafic <span class="hlt">vent</span> systems with reducing chemical environments that yield <span class="hlt">hydrothermal</span> fluids rich in methane, hydrogen, and organic carbon, thus providing energy sources to biological communities relevant to the origin and early evolution of life on Earth and the potential for life on other planets. Microbial-geochemical interactions are also important for understanding how deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> impact ocean biogeochemistry, especially in <span class="hlt">hydrothermal</span> plumes, where <span class="hlt">vent</span> fluids stimulate chemosynthetic microbial communities and microbes influence the oceanic fate of <span class="hlt">hydrothermally</span>-sourced elements. Many critical processes occur in the rising portion of <span class="hlt">hydrothermal</span> plumes, which are dynamic and challenging to sample. To address these questions and challenges, we developed methods for the in situ collection and preservation of paired microbiology and geochemical samples from rising <span class="hlt">hydrothermal</span> plumes. Samples were collected with ROV Jason from two <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems, Von Damm and Beebe, which are in close proximity to each other on the Mid Cayman Rise yet are quite distinct in terms of chemistry, temperature, and depth. Bulk geochemistry, spatially-resolved spectroscopy, and molecular microbiological approaches were applied to yield some of the first views into the dynamic biotic and abiotic processes operative in rising <span class="hlt">hydrothermal</span> plumes from an ultra-slow spreading system. Results indicate that the Cayman plumes are enriched in hydrogen, sulfur, and methane-utilizing microorganisms relative to background deep Caribbean seawater. Clear differences were observed between near-<span class="hlt">vent</span> samples, which were dominated by seafloor-derived organisms, and samples from the upper buoyant or non-buoyant plume. These Cayman plume microbes are distinct from those observed in plumes of faster spreading <span class="hlt">hydrothermal</span> systems such as those of the Guaymas and Lau Basins. Current efforts are focused on utilizing metagenomics and metatranscriptomics to define the metabolic potential and expression of specific microbial populations, spectroscopy to track mineralogy and redox state of particle-associated elements, and physical, chemical, and biological models to simulate the rising plume. These results are being integrated into a coupled ecosystem model with the ultimate goal of understanding the interplay between microbiology and geochemistry in rising <span class="hlt">hydrothermal</span> plumes and outcomes in terms of ocean biogeochemistry.</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://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://www.ncbi.nlm.nih.gov/pubmed/25244359','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25244359"><span id="translatedtitle">Identification and activity of acetate-assimilating bacteria in diffuse fluids <span class="hlt">venting</span> from two deep-sea <span class="hlt">hydrothermal</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>Winkel, Matthias; Pjevac, Petra; Kleiner, Manuel; Littmann, Sten; Meyerdierks, Anke; Amann, Rudolf; Mußmann, Marc</p> <p>2014-12-01</p> <p>Diffuse <span class="hlt">hydrothermal</span> fluids often contain organic compounds such as hydrocarbons, lipids, and organic acids. Microorganisms consuming these compounds at <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> are so far only known from cultivation-dependent studies. To identify potential heterotrophs without prior cultivation, we combined microbial community analysis with short-term incubations using (13)C-labeled acetate at two distinct <span class="hlt">hydrothermal</span> systems. We followed cell growth and assimilation of (13)C into single cells by nanoSIMS combined with fluorescence in situ hybridization (FISH). In 55 °C-fluids from the Menez Gwen <span class="hlt">hydrothermal</span> system/Mid-Atlantic Ridge, a novel epsilonproteobacterial group accounted for nearly all assimilation of acetate, representing the first aerobic acetate-consuming member of the Nautiliales. In contrast, Gammaproteobacteria dominated the (13) C-acetate assimilation in incubations of 37 °C-fluids from the back-arc <span class="hlt">hydrothermal</span> system in the Manus Basin/Papua New Guinea. Here, 16S rRNA gene sequences were mostly related to mesophilic Marinobacter, reflecting the high content of seawater in these fluids. The rapid growth of microorganisms upon acetate addition suggests that acetate consumers in diffuse fluids are copiotrophic opportunists, which quickly exploit their energy sources, whenever available under the spatially and temporally highly fluctuating conditions. Our data provide first insights into the heterotrophic microbial community, catalyzing an under-investigated part of microbial carbon cycling at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. PMID:25244359</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://www.osti.gov/scitech/servlets/purl/1234403','SCIGOV-DOEDE'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1234403"><span id="translatedtitle">Compilation of Rare Earth Element Analyses from US Geothermal Fields and Mid Ocean Ridge <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/dataexplorer">DOE Data Explorer</a></p> <p>Andrew Fowler</p> <p>2015-10-01</p> <p>Compilation of rare earth element and associated major and minor dissolved constituent analytical data for USA geothermal fields and global seafloor <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Data is in original units. Reference to and use of this data should be attributed to the original authors and publications according to the provisions outlined therein.</p> </li> <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://ntrs.nasa.gov/search.jsp?R=20060010264&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhydrothermal','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060010264&hterms=hydrothermal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhydrothermal"><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://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3647119','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3647119"><span id="translatedtitle">The pH and pCO2 dependence of sulfate reduction in shallow-sea <span class="hlt">hydrothermal</span> CO2 – <span class="hlt">venting</span> sediments (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>Bayraktarov, Elisa; Price, Roy E.; Ferdelman, Timothy G.; Finster, Kai</p> <p>2013-01-01</p> <p>Microbial sulfate reduction (SR) is a dominant process of organic matter mineralization in sulfate-rich anoxic environments at neutral pH. Recent studies have demonstrated SR in low pH environments, but investigations on the microbial activity at variable pH and CO2 partial pressure are still lacking. In this study, the effect of pH and pCO2 on microbial activity was investigated by incubation experiments with radioactive 35S targeting SR in sediments from the shallow-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> system of Milos, Greece, where pH is naturally decreased by CO2 release. Sediments differed in their physicochemical characteristics with distance from the main <span class="hlt">site</span> of fluid discharge. Adjacent to the <span class="hlt">vent</span> <span class="hlt">site</span> (T ~40–75°C, pH ~5), maximal sulfate reduction rates (SRR) were observed between pH 5 and 6. SR in <span class="hlt">hydrothermally</span> influenced sediments decreased at neutral pH. Sediments unaffected by <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> (T ~26°C, pH ~8) expressed the highest SRR between pH 6 and 7. Further experiments investigating the effect of pCO2 on SR revealed a steep decrease in activity when the partial pressure increased from 2 to 3 bar. Findings suggest that sulfate reducing microbial communities associated with <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> system are adapted to low pH and high CO2, while communities at control <span class="hlt">sites</span> required a higher pH for optimal activity. PMID:23658555</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://adsabs.harvard.edu/abs/2003AGUFM.T32A0920W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.T32A0920W"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">Venting</span> in the Southern Most Portion of the Mariana Backarc Spreading Center at 12.57 Degrees N</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.; Fryer, P.; Hulme, S.; Becker, N.; Curtis, A.; Moyer, C.</p> <p>2003-12-01</p> <p>The southernmost portion of the Mariana Trough is a complex zone of deformation and magmatism. The centerpiece of the trough is the Malaguana-Gadao Spreading Center Ridge, which has a morphology that is inflated relative to all of the other spreading segments in the Mariana Backarc Basin. This inflated morphology is similar to that of the EPR and is consistent with a high rate of eruption. Samples of lavas from the spreading center are island arc tholeiites, which typically contain higher concentrations of CO2 relative to MORBs. In February 2003 the NOAA <span class="hlt">VENTS</span> program conducted two CTD tow-yos in this area, revealing a <span class="hlt">hydrothermal</span> plume consistent with the presence of a high temperature <span class="hlt">hydrothermal</span> <span class="hlt">site</span>. In May 2003 we used the ROV Jason II to survey a <span class="hlt">hydrothermal</span> <span class="hlt">site</span> at 12 degrees 57.214'N, 143 degrees 37.147'E in a water depth of ~2860 m. Here we collected <span class="hlt">vent</span> fluids, sulfides, basalt, microbial mats, and macrofauna. Two styles of <span class="hlt">venting</span> were identified within an 80 m by 70 m area. Higher temperature <span class="hlt">venting</span> was located in cracks among extinct mounds that were 2-5 m high and wide and are nearly monomineralic (sphalerite) in composition. The exterior is soft and vuggy in contrast to the interior that has crystalline layers with bladed habit lining the orifices. Maximum temperatures of 248 degrees C were recorded 30 cm into these cracks, which were covered with abundant large provannid snails, Alvinoconcha Hessleri, and crabs. In contrast, lower temperature diffuse <span class="hlt">venting</span> (77 degrees C) emanated from mounds that have a porous structure that is composed of amorphous iron oxide and opal. These mounds are covered with microbial mats, which exhibit a high degree of biomass as detected by Cyto-13 nucleic acid epifluorescent staining. Filament and amorphous particulate morphotypes are observed in association with microbial cells, but sheaths have not been detected. These mats have a morphology that is similar to that of neutrophilic Fe-oxidizing bacteria. Fluid chemistry is consistent with a single source and with other back-arc derived <span class="hlt">hydrothermal</span> fluids that are enriched in alkalinity relative to bottom seawater. Extrapolated concentrations per kg of seawater are 0 mmol Mg, 36.2 mmol Ca, 7.3 mmol alkalinity, 544 chlorinity, 414 mmol Na, 32.2 mmol K, 0 mmol sulfate, 165 umol Sr, and 575 umol Li. Additional analyses are ongoing.</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 (δ13C 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 δ13C values remained largely unexplained, and it has been argued that δ13C 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 δ13C 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 δ13C, δ15N and δ34S 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 δ13C values of shrimp tissues, and slightly elevated δ15N values. To further support our findings, measurements of δ34S 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> </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://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://www.ncbi.nlm.nih.gov/pubmed/24983244','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24983244"><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=pubmed">PubMed</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/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 γ-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 γ-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/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 γ-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 γ-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/2014AGUFM.V21A4738D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.V21A4738D"><span id="translatedtitle">Recent Investigation of In-Situ pH in <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Fluids at Main Endeavour Field (MEF) and ASHES <span class="hlt">Vent</span> Field (ASHES): Implications for Dynamic Changes in Subseafloor <span class="hlt">Hydrothermal</span> System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ding, K.; Seyfried, W. E., Jr.; Tan, C.; Schaen, A. T.; Luhmann, A. J.</p> <p>2014-12-01</p> <p>In-situ pH is among the key factors affecting chemical reactions involved with fluid-rock interaction and metal transport in <span class="hlt">hydrothermal</span> systems. A small variation in pH will often result in a large difference in dissolved metal concentrations. For instance, at 400oC, a decrease of ~0.15 pH unit will cause dissolved Fe concentration to double in fluid coexisting with a Fe-bearing mineral assemblage. This parameter also offers us an opportunity to better understand processes controlling the temporal evolution of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluid chemistry at mid-ocean ridges. During our recent cruise AT 26-17 with newly upgraded DSV2 Alvin, in-situ measurements of pH were carried out along with gas-tight sampling of <span class="hlt">vent</span> fluids. Our efforts were focused at MEF and ASHES on the Juan de Fuca Ridge. These <span class="hlt">hydrothermal</span> systems have been shown to be particularly responsive to subseafloor seismic and magmatic events. The measured fluid temperature was approximately 333˚C and 300˚C at Dante <span class="hlt">vent</span> orifice of MEF and Inferno <span class="hlt">vent</span> orifice of ASHES, respectively. The corresponding measured in-situ pH values for both <span class="hlt">vents</span> are: 4.94 and 4.88, respectively. Dissolved gases and other species were also measured from gas-tight fluid samples providing a means of comparison with the in-situ data. As we have known the earthquake and magmatic activity often places the system at higher temperature and more reducing conditions in connection with a new evolutionary cycle. Comparing these relatively low in-situ pH values with those measured in the past, especially with the ones obtained at MEF in 1999 after an intense swarm of earthquakes, we see the system trending towards more acidic conditions along with decreasing temperature and dissolved H2 and H2S. Taking an example from Dante <span class="hlt">vent</span> <span class="hlt">site</span>, in-situ pH value of 5.15 was recorded with a measured temperature of 363oC two month after the event in 1999, which gives 0.2 pH unit greater than the more recent data. Measured dissolved H2 and H2S concentrations in 1999 were also much higher. Altogether these results reveal an ongoing trend toward more oxidizing and acidic stage along with cooling. More results will be discussed in this presentation with the emphasis on the factors that may have played the role in acidifying the system during the evolution cycle and its effect to metal mobility.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4801315','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4801315"><span id="translatedtitle">Quantifying dispersal from <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields in the western 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>Mitarai, Satoshi; Watanabe, Hiromi; Nakajima, Yuichi; Shchepetkin, Alexander F.; McWilliams, James C.</p> <p>2016-01-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> fields in the western Pacific Ocean are mostly distributed along spreading centers in submarine basins behind convergent plate boundaries. Larval dispersal resulting from deep-ocean circulations is one of the major factors influencing gene flow, diversity, and distributions of <span class="hlt">vent</span> animals. By combining a biophysical model and deep-profiling float experiments, we quantify potential larval dispersal of <span class="hlt">vent</span> species via ocean circulation in the western Pacific Ocean. We demonstrate that <span class="hlt">vent</span> fields within back-arc basins could be well connected without particular directionality, whereas basin-to-basin dispersal is expected to occur infrequently, once in tens to hundreds of thousands of years, with clear dispersal barriers and directionality associated with ocean currents. The southwest Pacific <span class="hlt">vent</span> complex, spanning more than 4,000 km, may be connected by the South Equatorial Current for species with a longer-than-average larval development time. Depending on larval dispersal depth, a strong western boundary current, the Kuroshio Current, could bridge <span class="hlt">vent</span> fields from the Okinawa Trough to the Izu-Bonin Arc, which are 1,200 km apart. Outcomes of this study should help marine ecologists estimate gene flow among <span class="hlt">vent</span> populations and design optimal marine conservation plans to protect one of the most unusual ecosystems on Earth. PMID:26929376</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 μm) 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 μm 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=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 δ34S 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 δ34SSO4 and δ18OSO4 as expected of microbial sulfate reduction. Instead, pore water δ34SSO4 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 δ34SSO4 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 δ34SSO4, 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 δ18OSO4 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 δ34S 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=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> <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/2014GeCoA.124...72L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GeCoA.124...72L"><span id="translatedtitle">Modeling microbial reaction rates in a submarine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimney wall</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>LaRowe, Douglas E.; Dale, Andrew W.; Aguilera, David R.; L'Heureux, Ivan; Amend, Jan P.; Regnier, Pierre</p> <p>2014-01-01</p> <p>The fluids emanating from active submarine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimneys provide a window into subseafloor processes and, through mixing with seawater, are responsible for steep thermal and compositional gradients that provide the energetic basis for diverse biological communities. Although several models have been developed to better understand the dynamic interplay of seawater, <span class="hlt">hydrothermal</span> fluid, minerals and microorganisms inside chimney walls, none provide a fully integrated approach to quantifying the biogeochemistry of these <span class="hlt">hydrothermal</span> systems. In an effort to remedy this, a fully coupled biogeochemical reaction-transport model of a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimney has been developed that explicitly quantifies the rates of microbial catalysis while taking into account geochemical processes such as fluid flow, solute transport and oxidation-reduction reactions associated with fluid mixing as a function of temperature. The metabolisms included in the reaction network are methanogenesis, aerobic oxidation of hydrogen, sulfide and methane and sulfate reduction by hydrogen and methane. Model results indicate that microbial catalysis is generally fastest in the hottest habitable portion of the <span class="hlt">vent</span> chimney (77-102 °C), and methane and sulfide oxidation peak near the seawater-side of the chimney. The fastest metabolisms are aerobic oxidation of H2 and sulfide and reduction of sulfate by H2 with maximum rates of 140, 900 and 800 pmol cm-3 d-1, respectively. The maximum rate of hydrogenotrophic methanogenesis is just under 0.03 pmol cm-3 d-1, the slowest of the metabolisms considered. Due to thermodynamic inhibition, there is no anaerobic oxidation of methane by sulfate (AOM). These simulations are consistent with <span class="hlt">vent</span> chimney metabolic activity inferred from phylogenetic data reported in the literature. The model developed here provides a quantitative approach to describing the rates of biogeochemical transformations in <span class="hlt">hydrothermal</span> systems and can be used to constrain the role of microbial activity in the deep subsurface.</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.ncbi.nlm.nih.gov/pubmed/23248622','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23248622"><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=pubmed">PubMed</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://adsabs.harvard.edu/abs/2013GeCoA.123..440T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GeCoA.123..440T"><span id="translatedtitle">Reconstructing the oxygen isotope composition of late Cambrian and Cretaceous <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluid</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Turchyn, Alexandra V.; Alt, Jeffrey C.; Brown, Shaun T.; DePaolo, Donald J.; Coggon, Rosalind M.; Chi, Guoxiang; Bédard, Jean H.; Skulski, Thomas</p> <p>2013-12-01</p> <p>Oxygen isotope analyses (δ18O) of 16 quartz-epidote pairs from late Cambrian (Betts Cove and Mings Bight, Newfoundland), Ordovician (Thetford Mines, Québec, Canada) and Cretaceous (Troodos, Cyprus) ophiolites are used to calculate the δ18O of the <span class="hlt">hydrothermal</span> fluids from which they crystallized. We combine these with 3 quartz-fluid inclusion measurements and 3 quartz-magnetite measurements from the Cambrian ophiolites to explore how the range in the δ18O of submarine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluid has varied between the late Cambrian, Cretaceous and today. The range of calculated δ18O values of <span class="hlt">vent</span> fluid (-4 to +7.4) is larger than that of modern seafloor <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluid (0 to +4). We employ two numerical models to ascertain whether this range is most consistent with changes in paleo-seawater δ18O or with changes in the reactive flow path in ancient <span class="hlt">hydrothermal</span> systems. A static calculation of the <span class="hlt">vent</span> fluid oxygen isotope composition as a function of the water-rock ratio suggests that in an ocean with a lower δ18O than today, the range of <span class="hlt">vent</span> fluid δ18O should be larger. Our data, however, show little evidence that the δ18O of the ocean was much lower than the global ice-free value of -1.2. A dual porosity model for reactive flow through fractured and porous media is used to model the relative evolution of the 87Sr/86Sr and δ18O of <span class="hlt">vent</span> fluid in contact with rock. Our 87Sr/86Sr and δ18O for Cretaceous epidotes suggest the strontium concentration of the Cretaceous oceans may have been much higher than at present. The 87Sr/86Sr and δ18O data from Cambrian epidotes are strikingly different from the younger samples, and are difficult to model unless fluid-rock interaction in the Cambrian <span class="hlt">hydrothermal</span> systems was substantially different. It is also possible that some of the quartz-epidote veins have been reset by obduction-related metamorphism. Our data suggest that the high calcium-to-sulfate ratio in early (and Cretaceous) seawater may have affected the degree of strontium isotope exchange, causing <span class="hlt">hydrothermal</span> fluids to have 87Sr/86Sr closer to that of seawater than in modern systems.</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/2014AGUFM.V21A4725K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.V21A4725K"><span id="translatedtitle">Estimating the Heat and Mass Flux at the ASHES <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Field with the Sentry Autonomous Underwater Vehicle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kinsey, J. C.; Crone, T. J.; Mittelstaedt, E. L.; Medagoda, L.; Fourie, D.; Nakamura, K.</p> <p>2014-12-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">venting</span> influences ocean chemistry, the thermal and chemical structure of the oceanic crust, the style of accretion at mid-ocean ridges, and the evolution of unique and diverse chemosynthetic ecosystems. Surprisingly, only a few studies have attempted to constrain the volume and heat flux of entire <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields given that axially-hosted <span class="hlt">hydrothermal</span> systems are estimated to be responsible for ~20-25% of the total heat flux out of the Earth's interior, as well as potentially playing a large role in global and local biogeochemical cycles. However, same-<span class="hlt">site</span> estimates can vary greatly, such as at the Lucky Strike Field where estimates range from 100 MW to 3800 MW. We report a July 2014 field program with the Sentry AUV that obtains the water velocity and heat measurements necessary to estimate the total heat and mass flux emanating from the ASHES <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field. We equipped Sentry with a Nortek acoustic Doppler velocimeter (ADV) with an inertial measurement unit attached, two acoustic Doppler current profilers (ADCPs), and two SBE3 temperature probes, to measure the temperature and water velocity. This sensing suite provided more accurate measurements than previous AUV based studies. A control volume approach was employed in which Sentry was pre-programmed to survey a 150m by 150m box centered over the <span class="hlt">vent</span> field flying a "mowing the lawn" pattern at 5m trackline spacing followed by a survey of the perimeter. During a 40 hour survey, the pattern was repeated 9 times allowing us to obtain observations over multiple tidal cycles. Concurrent lowered ADCP (LADCP) measurements were also obtained. Water velocity data obtained with Sentry was corrected for platform motion and then combined with the temperature measurements to estimate heat flux. Analysis of this data is on-going, however these experiments permit us to quantify the heat and mass exiting the control volume, and potentially provide the most accurate and highest resolution heat and mass flux estimates at a <span class="hlt">hydrothermal</span> field to date.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25337895','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25337895"><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=pubmed">PubMed</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.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://adsabs.harvard.edu/abs/2002EGSGA..27.6696B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27.6696B"><span id="translatedtitle">The Use of Environmental Magnetic Methodology To Look At <span class="hlt">Hydrothermal</span> Fluid Circulation Through Sediment Near An Active <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>Brandau, A.; Urbat, M.</p> <p></p> <p>Variations of magnetomineralogical contents of holocene-pleistocene marine sedi- ments from <span class="hlt">Sites</span> 1036 A-C (Ocean Drilling Program Leg 169) sensitively reflect the lateral and vertical convection of <span class="hlt">hydrothermal</span> fluids in the Dead Dog <span class="hlt">Vent</span> Field (Juan de Fuca Ridge). Clay mineralogical analyses (Lackschewitz et al., 2000) pro- vides a record of authigenesis associated with high heat flow, that indicates a temper- ature gradient of 8C/m (206C and 268C at 21.8 and 27.8 meters below seafloor respectively). Our magnetic results indicate gradual as well as abrupt changes of the magnetomineralogical contents (dissolution, precipitation of iron oxides and/or sul- fides) as a function of temperature accelerated sediment alteration and thereby refine a previous determination of sediment alteration facies at Holes 1036 A-C based on shipboard data. The combination of the rock magnetic dataset with the non-magnetic results leads to a better understanding of this dynamic <span class="hlt">hydrothermal</span> system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26316638','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26316638"><span id="translatedtitle">Genome Sequence of Bacillus alveayuensis Strain 24KAM51, a Halotolerant Thermophile 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=pubmed">PubMed</a></p> <p>Filippidou, Sevasti; Wunderlin, Tina; Junier, Thomas; Jeanneret, Nicole; Johnson, Shannon; McMurry, Kim; Gleasner, Cheryl D; Lo, Chien-Chi; Li, Po-E; Vuyisich, Momchilo; Chain, Patrick S; Junier, Pilar</p> <p>2015-01-01</p> <p>Bacillus alveayuensis strain 24KAM51 was isolated from a marine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> in Milos, Greece. Its genome depicts interesting features of halotolerance and resistance to heavy metals. PMID:26316638</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/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://adsabs.harvard.edu/abs/1993JGR....98.9625C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993JGR....98.9625C"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> methane <span class="hlt">venting</span> between 12°N and 26°N 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>Charlou, Jean-Luc; Donval, Jean-Pierre</p> <p>1993-06-01</p> <p>Hydrographic surveys along the Mid-Atlantic Ridge (MAR) between 12°N and 26°N, carried out from 1984 to 1990, show a variable pattern of CH4-rich water column plumes. The vertical distribution of CH4 at stations located every 20-40 km is presented along this 1200-km-long section of the MAR. CH4 <span class="hlt">venting</span> is clearly demonstrated. CH4-enriched fluids rise from <span class="hlt">vents</span> as plumes; spreading is confined to the axial valley due to the topography of the MAR. CH4 contents from 45 nmol to 675 nmol/kg are measured in the buoyant plumes above the two active <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> (MARK 23°N; TAG 26°N) known at present, whereas CH4 anomalies up to 3.6 nmol/kg are typically observed in plumes emitted either on the inner floor, on the walls, and/or at the top of the rift mountains along the studied ridge section. CH4 concentrations (45 μmol to 144 μmol/kg) in MARK and TAG <span class="hlt">vent</span> fluids are of the same order of magnitude as those found in the East Pacific Rise fluids. Even though CH4 is known to be unstable with respect to oxidation by dissolved oxygen, and in spite of its microbial oxidation in plumes, these results confirm CH4 to be a good indicator to track <span class="hlt">hydrothermal</span> plumes and to map the variation of <span class="hlt">hydrothermal</span> activity along mid oceanic ridges. Moreover, between 12° and 26°N along the MAR, CH4 results show that while <span class="hlt">hydrothermal</span> activity is present everywhere along the ridge, it is predominant near fracture zones (FZ) (Kane FZ, 15°20'N FZ). Comparison of CH4 tracer with total dissolvable manganese (TDM) tracer in plumes allows us to differentiate subseafloor <span class="hlt">hydrothermal</span> processes. The high TDM/CH4 found above TAG and MARK areas is indicative of basalt-seawater interaction, while at 15°N the low TDM/CH4 provides evidence of fluid circulation in ultrabasic rocks. CH4 data confirm the association between mantle degassing, <span class="hlt">hydrothermal</span> activity, and serpentinization along this 12°-26°N section of the Mid-Atlantic Ridge.</p> </li> <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://www.ncbi.nlm.nih.gov/pubmed/21527710','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21527710"><span id="translatedtitle">Surface-generated mesoscale eddies transport deep-sea products from <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>Adams, Diane K; McGillicuddy, Dennis J; Zamudio, Luis; Thurnherr, Andreas M; Liang, Xinfeng; Rouxel, Olivier; German, Christopher R; Mullineaux, Lauren S</p> <p>2011-04-29</p> <p>Atmospheric forcing, which is known to have a 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 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. Transport by these deep-reaching eddies provides a mechanism for spreading the <span class="hlt">hydrothermal</span> chemical and heat flux into the deep-ocean interior and for dispersing propagules hundreds of kilometers between isolated and ephemeral communities. Because the eddies interacting with the East Pacific Rise 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. PMID:21527710</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011Sci...332..580A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011Sci...332..580A"><span id="translatedtitle">Surface-Generated Mesoscale Eddies Transport Deep-Sea Products from <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>Adams, Diane K.; McGillicuddy, Dennis J.; Zamudio, Luis; Thurnherr, Andreas M.; Liang, Xinfeng; Rouxel, Olivier; German, Christopher R.; Mullineaux, Lauren S.</p> <p>2011-04-01</p> <p>Atmospheric forcing, which is known to have a 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 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. Transport by these deep-reaching eddies provides a mechanism for spreading the <span class="hlt">hydrothermal</span> chemical and heat flux into the deep-ocean interior and for dispersing propagules hundreds of kilometers between isolated and ephemeral communities. Because the eddies interacting with the East Pacific Rise 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.</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.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://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/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/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/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.ncbi.nlm.nih.gov/pubmed/26508672','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26508672"><span id="translatedtitle">Genome sequence of Bacillus sp. CHD6a, isolated from the shallow-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>Lin, Wenxin; Chen, Hong; Chen, Qi; Liu, Yanting; Jiao, Nianzhi; Zheng, Qiang</p> <p>2016-02-01</p> <p>Bacillus sp. CHD6a, which can produce oval endosperms, isolated from the shallow-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> systems off northeast Taiwan's coast. Here, we report the draft genome sequence of Bacillus sp. CHD6a. It comprises ~3.97Mb in 55 contigs with the G+C content of 39.9%, and a total of 3740 protein-coding genes were obtained. PMID:26508672</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://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.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 μm) 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://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.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://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=244008','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=244008"><span id="translatedtitle">Chemolithotrophic Sulfur-Oxidizing Bacteria from the Galapagos Rift <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>Ruby, E. G.; Wirsen, C. O.; Jannasch, H. W.</p> <p>1981-01-01</p> <p>Three distinct physiological types of sulfur-oxidizing bacteria were enriched and isolated from samples collected at several deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> (2,550 m) of the Galapagos Rift ocean floor spreading center. Twelve strains of the obligately chemolithotrophic genus Thiomicrospira were obtained from <span class="hlt">venting</span> water and from microbial mats covering surfaces in the immediate vicinity of the <span class="hlt">vents</span>. From these and other sources two types of obligately heterotrophic sulfur oxidizers were repeatedly isolated that presumably oxidized thiosulfate either to sulfate (acid producing; 9 strains) or to polythionates (base producing; 74 strains). The former were thiobacilli-like, exhibiting a thiosulfate-stimulated increase in growth and CO2 incorporation, whereas the latter were similar to previously encountered pseudomonad-like heterotrophs. The presence of chemolithotrophic sulfur-oxidizing bacteria in the sulfide-containing <span class="hlt">hydrothermal</span> water supports the hypothesis that chemosynthesis provides a substantial primary food source for the rich populations of invertebrates found in the immediate vicinity of the <span class="hlt">vents</span>. Images PMID:16345831</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://adsabs.harvard.edu/abs/1998DSRII..45..303M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998DSRII..45..303M"><span id="translatedtitle">Diversity of deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> Archaea from Loihi Seamount, Hawaii</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moyer, Craig L.; Tiedje, James M.; Dobbs, Fred C.; Karl, David M.</p> <p>1998-01-01</p> <p>Through an examination of SSU rDNA (genes coding for SSU rRNA), the molecular phylogeny of the domain Archaea (e.g. one of the three major lineages of life) was analyzed from a microbial mat at an active, deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystem located at Pele's <span class="hlt">Vents</span> on the summit of Loihi Seamount, Hawaii. These SSU rDNAs were amplified from extracted microbial mat genomic DNA by PCR, cloned into a plasmid vector, and sequenced. The derived archaeal sequences were then used to infer the evolutionary relationships between these microbial mat community members and their closest known relatives. Of the four clones initially chosen for sequence analysis, a cluster of three phylogenetically similar PV A (Pele's <span class="hlt">Vents</span> Archaea) clones all contained in the archaeal group I lineage of the marine Crenarchaeota were detected. A single PV A clone was contained in the archaeal group II lineage of the marine Euryarchaeota. All four of the PV A clones are novel and constitute the discovery of new archaeal taxa. From further rarefaction results of 75 archaeal SSU rDNA clones, we estimate the organismal diversity of this domain from the microbial mats located at Pele's <span class="hlt">Vents</span> to be significantly greater than that of the bacterial domain from this same ecosystem. Analyses of archaeal diversity at both the organismal (i.e. rarefaction) and phylogenetic level suggest that <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, such as Pele's <span class="hlt">Vents</span>, are intimately linked with marine archaeoplankton (a recently discovered component of marine picoplankton) detected from oceans around the world.</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/25428684','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25428684"><span id="translatedtitle">An origin-of-life reactor to simulate alkaline <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>Herschy, Barry; Whicher, Alexandra; Camprubi, Eloi; Watson, Cameron; Dartnell, Lewis; Ward, John; Evans, Julian R G; Lane, Nick</p> <p>2014-12-01</p> <p>Chemiosmotic coupling is universal: practically all cells harness electrochemical proton gradients across membranes to drive ATP synthesis, powering biochemistry. Autotrophic cells, including phototrophs and chemolithotrophs, also use proton gradients to power carbon fixation directly. The universality of chemiosmotic coupling suggests that it arose very early in evolution, but its origins are obscure. Alkaline <span class="hlt">hydrothermal</span> systems sustain natural proton gradients across the thin inorganic barriers of interconnected micropores within deep-sea <span class="hlt">vents</span>. In Hadean oceans, these inorganic barriers should have contained catalytic Fe(Ni)S minerals similar in structure to cofactors in modern metabolic enzymes, suggesting a possible abiotic origin of chemiosmotic coupling. The continuous supply of H2 and CO2 from <span class="hlt">vent</span> fluids and early oceans, respectively, offers further parallels with the biochemistry of ancient autotrophic cells, notably the acetyl CoA pathway in archaea and bacteria. However, the precise mechanisms by which natural proton gradients, H2, CO2 and metal sulphides could have driven organic synthesis are uncertain, and theoretical ideas lack empirical support. We have built a simple electrochemical reactor to simulate conditions in alkaline <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, allowing investigation of the possibility that abiotic <span class="hlt">vent</span> chemistry could prefigure the origins of biochemistry. We discuss the construction and testing of the reactor, describing the precipitation of thin-walled, inorganic structures containing nickel-doped mackinawite, a catalytic Fe(Ni)S mineral, under prebiotic ocean conditions. These simulated <span class="hlt">vent</span> structures appear to generate low yields of simple organics. Synthetic microporous matrices can concentrate organics by thermophoresis over several orders of magnitude under continuous open-flow <span class="hlt">vent</span> conditions. PMID:25428684</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.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=4568656','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4568656"><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=pmc">PubMed Central</a></p> <p>Klose, Julia; Polz, Martin F.; Wagner, Michael; Schimak, Mario P.; Gollner, Sabine; Bright, Monika</p> <p>2015-01-01</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://adsabs.harvard.edu/abs/2012AGUFM.B42C..07L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.B42C..07L"><span id="translatedtitle">Quantifying metabolic rates in submarine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimneys: A reaction transport model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>LaRowe, D.; Dale, A.; Aguilera, D.; Amend, J. P.; Regnier, P.</p> <p>2012-12-01</p> <p>The fluids emanating from active submarine <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimneys provide a window into subseafloor processes and, through mixing with seawater, are responsible for steep thermal and compositional gradients that provide the energetic basis for diverse biological communities. Although several models have been developed to better understand the dynamic interplay of seawater, <span class="hlt">hydrothermal</span> fluid, minerals and microorganisms inside chimney walls, none provide a fully integrated approach to quantifying the biogeochemistry of these <span class="hlt">hydrothermal</span> systems. In an effort to remedy this, a fully coupled biogeochemical reaction transport model of a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimney has been developed that explicitly quantifies the rate of microbial catalysis while taking into account geochemical processes such as fluid flow, solute transport and oxidation-reduction reactions associated with fluid mixing as a function of temperature. Methanogenesis, hydrogen oxidation by oxygen and sulfate, sulfide oxidation by oxygen and methane oxidation by oxygen and sulfate are the metabolisms included in the reaction network. Model results indicate that microbial catalysis is fastest in the hottest habitable portion of the <span class="hlt">vent</span> chimney except for methane oxidation by oxygen, which peaks near the seawater-side of the chimney at 20 nmol /cm^3 yr. The dominant metabolisms in the chimney are hydrogen oxidation by sulfate and oxygen and sulfide oxidation at peak rates 3200 , 300 and 900 nmol /cm^3 yr, respectively. The maximum rate of hydrogenotrophic methanogensis is just under 0.07 nmol /cm^3 yr, the slowest of the metabolisms considered. Due to thermodynamic inhibition, there is no anaerobic oxidation of methane by sulfate (AOM). The model developed here provides a quantitative approach to understanding the rates of biogeochemical transformations in <span class="hlt">hydrothermal</span> systems and can be used to better understand the role of microbial activity in the deep subsurface.</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://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://www.ncbi.nlm.nih.gov/pubmed/24080408','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24080408"><span id="translatedtitle">Proteomic responses to metal-induced oxidative stress in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>-living mussels, Bathymodiolus sp., on the Southwest Indian Ridge.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cole, Catherine; Coelho, Ana Varela; James, Rachael H; Connelly, Doug; Sheehan, David</p> <p>2014-05-01</p> <p>Bathymodiolin mussels are amongst the dominant fauna occupying <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> ecosystems throughout the World's oceans. This subfamily inhabits a highly ephemeral and variable environment, where exceptionally high concentrations of reduced sulphur species and heavy metals necessitate adaptation of specialised detoxification mechanisms. Whilst cellular responses to common anthropogenic pollutants are well-studied in shallow-water species, they remain limited in deep-sea <span class="hlt">vent</span> fauna. Bathymodiolus sp. were sampled from two newly-discovered <span class="hlt">vent</span> <span class="hlt">sites</span> on the Southwest Indian Ridge (Tiamat and Knuckers Gaff) by the remotely operated vehicle (ROV) Kiel 6000 during the RRS James Cook cruise, JC 067 in November 2011. Here, we use redox proteomics to investigate the effects of tissue metal accumulation on protein expression and thiol oxidation in gill. Following 2D PAGE, we demonstrate a significant difference in intensity in 30 protein spots in this organ between the two <span class="hlt">vent</span> <span class="hlt">sites</span> out of 205 matched spots. We also see significant variations in thiol oxidation in 15 spots, out of 143 matched. At Tiamat, 23 protein spots are up-regulated compared to Knuckers Gaff and we identify 5 of these with important roles in metabolism, cell structure, stress response, and redox homeostasis. We suggest that increased metal exposure triggers changes in the proteome, regulating tissue uptake. This is evident both between <span class="hlt">vent</span> <span class="hlt">sites</span> and across a chemical gradient within the Knuckers Gaff <span class="hlt">vent</span> <span class="hlt">site</span>. Our findings highlight the importance of proteomic plasticity in successful adaptation to the spatially and temporally fluctuating chemical environments that are characteristic of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> habitats. PMID:24080408</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010DokES.430...62D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010DokES.430...62D"><span id="translatedtitle">The concentration function of the bottom fauna at the deep sea <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>Demina, L. L.</p> <p>2010-01-01</p> <p>Specific features of the concentration of a group of chemical elements in the dominant bottom organisms are analyzed. The studied organisms inhabit geochemically different <span class="hlt">hydrothermal</span> fields: Menez-Gwen, Broken-Spur, and Rainbow on the Mid Atlantic Ridge (MAR), as well as 9°50'N and Guyamas on the East Pacific Rise (EPR). It was revealed for the first time that bottom organisms accumulate 102 to 105 times less the macro-ions of marine water Na and K from the water of biotopes than heavy metals. The intensive concentration of chemical elements, especially of heavy metals, and the high biomasses of bottom organisms associated with <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> suggest that this fauna serves as a powerful deepwater biofilter. The absence of pronounced differences between values of coefficients of accumulation for the same metals in the benthos of various MAR and EPR fields evidences the uniformity of the concentration function of the <span class="hlt">hydrothermal</span> fauna.</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://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 (δ13C and δ15N) 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://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 (δ13C and δ15N) 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://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.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://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://adsabs.harvard.edu/abs/2012AGUFMOS13A1696Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMOS13A1696Y"><span id="translatedtitle">Structural and functional diversity of microbial communities beneath the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> at the Iheya North field of the Mid-Okinawa Trough (IODP Expedition 331)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yanagawa, K.; Nunoura, T.; Kawagucci, S.; Hirai, M.; Sunamura, M.; Breuker, A.; Brandt, L.; House, C. H.; McAllister, S. M.; Moyer, C. L.; Takai, K.</p> <p>2012-12-01</p> <p>Complex and diverse microbial communities in deep-sea <span class="hlt">hydrothermal</span> fluids are apparently different from those in ambient seawater, some of which are predicted to migrate along <span class="hlt">hydrothermal</span> vein from "subvent biosphere". Subseafloor environment just beneath active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> has been expected to be one of the most conceivable habitats for metabolically active and diverse microbial community. We conducted the scientific ocean drilling (IODP Expedition 331) for the Iheya North <span class="hlt">hydrothermal</span> field in the Mid-Okinawa Trough in Sept. 2010, and collected core samples from the subseafloor biosphere beneath the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>. IODP <span class="hlt">Site</span> C0014 was located 450 m east off the main <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>. Temperature exceeded the limit of life at the depth of approximately 40 m below the seafloor. Both microscopy and quantitative PCR analyses successfully detected microbial populations in the shallower zone above 15 mbsf. However, the cultivation attempts of (hyper-)thermophiles were unsuccessful all over the depth. Culture-independent molecular biological experiments showed that microbial community composition distinctly changed with depth, possibly because of physicochemical conditions such as methane, sulfate and temperature. Microbial activities of methanogenesis and anaerobic methane oxidation were in accordance with the geochemical profiles of methane and sulfate. These results indicated the presence of functionally active subseafloor microbial communities but those were different from expected members in subvent biosphere. <span class="hlt">Site</span> C0017 located 1.6 km east off the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> is a potential seawater recharge zone of the <span class="hlt">hydrothermal</span> system, where seawater penetrates into the oceanic crust. The lithostratigraphy consists of characteristic coarse angular pumiceous gravel, lying above and below hemipelagic mud, in which high permeability may allow entrainment of seawater. As is the case with sedimentary subsurface environments, uncultivated archaeal groups were dominantly detected in the hemipelagic sediment above and below pumice layer. In contrast, the ammonia-oxidizing archaea (Nitrosopumilales) were outstandingly dominant at pumice layer of around 20 mbsf, possibly related to oxidative seawater transport. At the deeper layer of around 150 mbsf, where high temperature over 90°C was recorded, microbial community structure was similar to that in high temperature zone of <span class="hlt">Site</span> C0014. Our data suggest that the temperature gradient formed by <span class="hlt">hydrothermal</span> activity is one of the important factors controlling changes in subseafloor microbial communities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....2858T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....2858T"><span id="translatedtitle">High-Resolution Magnetic Field and Bathymetric Imaging of <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Areas using Autonomous Underwater Vehicles, Remotely Operated Vehicles and Submersibles</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.</p> <p>2003-04-01</p> <p>High-resolution, near-bottom bathymetric and magnetic field surveys have been carried out over <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> areas using the autonomous underwater vehicle ABE, the ROV Jason and ALVIN. Bathymetry is measured using a 675 kHz, scanning pencil-beam altimeter and, most recently, a 200 kHz swath mapping sonar. Vehicle depth is obtained by pressure sensor and vector magnetic field is measured using either a 3-axis fluxgate or, most recently, a digital magneto-resistor sensor. Typical survey altitude ranges from 20 m (Jason, ALVIN) to 40-60 m (ABE), with line spacing ranging from 20 to 40-60 m respectively. This survey geometry provides sufficient resolution for the detection of magnetic anomalies associated with geological features, most notably <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. We present detailed surveys over 5 <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> found at mid-ocean ridges that range from fast to slow spreading. The TAG <span class="hlt">hydrothermal</span> area, on the slow spreading Mid-Atlantic Ridge, was imaged using ALVIN in 1993 and has a magnetic low directly beneath the active chimney complex. On the intermediate-rate Endeavour segment of the Juan de Fuca Ridge (JDF), we imaged individual chimneys of Main Endeavour Field (MEF) and found that they are associated with discrete magnetic lows. On Explorer Ridge, ABE mapping in 2002 revealed that the Magic Mountain <span class="hlt">hydrothermal</span> area is also associated with a region of low magnetization. In 2002, at the intermediate-rate Galapagos Rift at 86W, ABE mapped the original "Rose Garden" <span class="hlt">hydrothermal</span> area, which has now become inactive. This <span class="hlt">site</span> has a magnetic low associated with it while only 200 m NW of this <span class="hlt">site</span>, an area of recent low-T <span class="hlt">hydrothermal</span> activity (i.e. Rosebud <span class="hlt">site</span>) does not produce a magnetic response. A 2001 ABE bathymetric and magnetic survey at the EPR crest at 9 50N shows weak magnetic anomaly lows associated with active high-T <span class="hlt">venting</span> in the axial trough. The observed magnetic anomalies share a number of common features, most notably a circular plan view geometry (typical diameter ˜100m) that indicates a discrete and highly localized anomalous magnetization source (i.e. an up-flow pipe geometry). Magnetic lows are found at both active and inactive (or relict) <span class="hlt">vent</span> <span class="hlt">sites</span> indicating that crustal alteration of the extrusive basalt rather than thermal demagnetization is the likely cause for low magnetization. Near-bottom magnetic and bathymetric surveys can be successful in locating zones of active and inactive <span class="hlt">hydrothermal</span> activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=544242','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=544242"><span id="translatedtitle">Mercury Adaptation among Bacteria 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>Vetriani, Costantino; Chew, Yein S.; Miller, Susan M.; Yagi, Jane; Coombs, Jonna; Lutz, Richard A.; Barkay, Tamar</p> <p>2005-01-01</p> <p>Since deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids are enriched with toxic metals, it was hypothesized that (i) the biota in the vicinity of a <span class="hlt">vent</span> is adapted to life in the presence of toxic metals and (ii) metal toxicity is modulated by the steep physical-chemical gradients that occur when anoxic, hot fluids are mixed with cold oxygenated seawater. We collected bacterial biomass at different distances from a diffuse flow <span class="hlt">vent</span> at 9°N on the East Pacific Rise and tested these hypotheses by examining the effect of mercuric mercury [Hg(II)] on <span class="hlt">vent</span> bacteria. Four of six moderate thermophiles, most of which were <span class="hlt">vent</span> isolates belonging to the genus Alcanivorax, and six of eight mesophiles from the <span class="hlt">vent</span> plume were resistant to >10 μM Hg(II) and reduced it to elemental mercury [Hg(0)]. However, four psychrophiles that were isolated from a nearby inactive sulfide structure were Hg(II) sensitive. A neighbor-joining tree constructed from the deduced amino acids of a PCR-amplified fragment of merA, the gene encoding the mercuric reductase (MR), showed that sequences obtained from the <span class="hlt">vent</span> moderate thermophiles formed a unique cluster (bootstrap value, 100) in the MR phylogenetic tree, which expanded the known diversity of this locus. The temperature optimum for Hg(II) reduction by resting cells and MR activity in crude cell extracts of a <span class="hlt">vent</span> moderate thermophile corresponded to its optimal growth temperature, 45°C. However, the optimal temperature for activity of the MR encoded by transposon Tn501 was found to be 55 to 65°C, suggesting that, in spite of its original isolation from a mesophile, this MR is a thermophilic enzyme that may represent a relic of early evolution in high-temperature environments. Results showing that there is enrichment of Hg(II) resistance among <span class="hlt">vent</span> bacteria suggest that these bacteria have an ecological role in mercury detoxification in the <span class="hlt">vent</span> environment and, together with the thermophilicity of MR, point to geothermal environments as a likely niche for the evolution of bacterial mercury resistance. PMID:15640191</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.B13A0173H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.B13A0173H"><span id="translatedtitle">Evidence for Pulsed <span class="hlt">Hydrothermal</span> <span class="hlt">Venting</span> from Young Abyssal Hills on the EPR Flank Suggests Frequent Seismic Pumping of Ridge Flank Fluid Flow</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haymon, R. M.; MacDonald, K. C.; Benjamin, S. B.; Ehrhardt, C. J.</p> <p>2004-12-01</p> <p>Although measured heat flow suggests that 40-50% of oceanic <span class="hlt">hydrothermal</span> heat and fluid flux is from young (0.1-5 Ma) abyssal hill terrain on MOR flanks, <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in this setting rarely have been found. On the EPR flanks, seafloor evidence of <span class="hlt">venting</span> from abyssal hills has been discovered recently at two <span class="hlt">sites</span>: on ˜0.1 Ma seafloor at 10° 20'N, 103° 33.2'W ("Tevnia <span class="hlt">Site</span>") and on ˜0.5 Ma seafloor at 9° 27'N, 104° 32.3'W ("Macrobes <span class="hlt">Site</span>"). Manifestations of <span class="hlt">venting</span> at these <span class="hlt">sites</span> include: fault scarp <span class="hlt">hydrothermal</span> mineralization and macrofauna; fault scarp flocculations containing hyperthermophilic microbes; and hilltop sediment mounds and craters possibly created by fluid "blow-outs." <span class="hlt">Hydrothermal</span> deposits recovered at the ˜0.1 Ma "Tevnia <span class="hlt">Site</span>" are fault breccias that record many episodes of brecciation followed by <span class="hlt">hydrothermal</span> cementation (Benjamin et al., this session). Tubeworm casings, live crabs, and "dandelions" observed at this <span class="hlt">site</span> indicate that the most recent episode of <span class="hlt">venting</span> was active during, or shortly before, this <span class="hlt">site</span> was visited with Alvin in 1994. To create the 200 m-high axis-facing fault scarp at Tevnia <span class="hlt">Site</span> in 100,000 years, an average uplift rate of at least 2 cm/y is required. Since off-axis earthquakes located on abyssal hill fault scarps typically are <M5, it is likely that each episode of slip has small vertical displacement (a few cm). Therefore fault slippage must repeat on a decadal timescale to match the observed rate of hill uplift, probably breaking open the fault scarp and rejuvenating <span class="hlt">hydrothermal</span> flow on a very frequent basis. In addition, close proximity to Clipperton Transform may subject Tevnia <span class="hlt">Site</span> to frequent M5-M6 seismic events with strong ground shaking and hydraulic pressure pulses capable of breaking open subseafloor pathways clogged with fragile minerals. We hypothesize that the multiple brecciation/cementation events recorded in the Tevnia <span class="hlt">Site</span> samples, and biological evidence for recent <span class="hlt">venting</span> at the <span class="hlt">site</span>, are evidence that <span class="hlt">hydrothermal</span> plumbing systems are maintained semi-continuously over 100,000 years by tectonic shaking and reactivation every few years-to-decades as abyssal hills are uplifted on ridge flanks. Hyperthermophiles identified in microbial floc on the axis-facing fault scarp at the ˜0.5 Ma "Macrobes <span class="hlt">Site</span>" are associated with chalcopyrite particles (Ehrhardt et al., this session). These observations indicate recent, transient <span class="hlt">venting</span> of high-T (at least 250° C), Cu-rich fluids from the fault scarp. The hilltop here has many meter-scale sediment mounds and craters (macs). These appear to be small mud volcanoes that have formed at different times from fluids expelled episodically through the thin sediments blanketing the hilltop. Formation of macs may be triggered by frequent (decadal) seismic events that also produce transient bursts of high T fluid flow from the adjacent fault scarp. Hyperthermophiles in the subsurface may flush out and bloom on the fault scarp during these events, and then remain dormant until the next event. The combined evidence from the two EPR ridge flank <span class="hlt">sites</span> points to seismic pumping of EPR abyssal hill <span class="hlt">hydrothermal</span> pulses every few years-to-decades. These frequent <span class="hlt">hydrothermal</span> pulses may be important in sustaining ridge flank biota. Monitoring of EPR abyssal hill fault scarps is needed to test these ideas.</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/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://adsabs.harvard.edu/abs/1994DSRI...41..993J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994DSRI...41..993J"><span id="translatedtitle">Biogeochemistry of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mussel communities: the deep-sea analogue to the intertidal zone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Johnson, Kenneth S.; Childress, James J.; Beehler, Carl L.; Sakamoto, Carole M.</p> <p>1994-07-01</p> <p>Continuous measurements of sulfide, silicate and temperature were made in situ from the submersible Alvin in the Rose Garden and New <span class="hlt">Vent</span> <span class="hlt">hydrothermal</span> fields of the Galapagos Spreading Center. Continuous measurements of temperature also were made for an 18 day period in the Rose Garden field. The results demonstrate several adaptations that appear to have contributed to the success of the <span class="hlt">vent</span> mussel Bathymodiolus thermophilus in the Rose Garden. Dense clusters of B. thermophilus can disperse the <span class="hlt">hydrothermal</span> fluids laterally for distances of several meters. This results in a large increase in the area of the redox transition zone, where both dissolved oxygen and hydrogen sulfide are available. As a result, the animal communities can grow to occupy areas that would not otherwise provide adequate reduced substrates. Measurements of the temperature demonstrate a distinct tidal periodicity. This periodicity will result in a large range of environmental conditions within the <span class="hlt">vent</span> community. The mussel can tolerate these wide ranges in condition because of its ability to accept long periods of anoxia and to filter feed.</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://adsabs.harvard.edu/abs/2009AGUFMOS12A..08H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMOS12A..08H"><span id="translatedtitle">Molecular Diversity and Activity of Methanogens in the Subseafloor at Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> of the Pacific Ocean (Invited)</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.; Merkel, A.; Holden, J. F.; Lilley, M. D.; Butterfield, D. A.</p> <p>2009-12-01</p> <p>Methanogenesis is thought to represent one of the most ancient metabolic pathways on Earth, and methanogens may serve as important primary producers in warm crustal habitats at deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Many of these obligate chemolithoautotrophs depend solely on geochemically-derived energy and carbon sources and grow at high temperatures under strictly anaerobic conditions. A combined geochemical and microbiological approach was used to determine the distribution and molecular diversity of methanogens in low temperature diffuse <span class="hlt">vent</span> fluids from the Endeavour Segment R2K ISS <span class="hlt">site</span>, as well as Axial Seamount and volcanoes of the Mariana Arc. Geochemical data from hot and adjacent warm diffuse <span class="hlt">vent</span> fluids provided chemical indicators to guide sample selection for detailed polymerase chain reaction (PCR)-based analysis of the key enzyme for methane formation, methyl-coenzyme M reductase (mcrA), as well as archaeal 16S rRNA genes. At most Endeavour <span class="hlt">vent</span> <span class="hlt">sites</span>, hydrogen concentrations were too low to support hydrogenotrophic methanogensis directly and only one diffuse <span class="hlt">site</span>, Easter Island, had a positive signal for the mcrA gene. These sequences were most closely related to members of the order Methanococcales, as well as anaerobic methane oxidizers (ANME-1). The presence of ANME, which are rarely found in non-sedimented marine environments, is another line of evidence supporting the occurrence of buried sediments at Endeavour. At Axial, a number of diffuse <span class="hlt">vents</span> have strong chemical indicators of methanogenesis. Methanogenic communities were detected at 3 <span class="hlt">sites</span> on the southeast side of the caldera: the northern end of the 1998 lava flow, the International District, and on the pre-1987 lava flow. Time series work at Marker 113 showed that in 4 different years over the last 6 years methanogenic communities are active and abundant, suggesting a stable anaerobic, warm subseafloor habitat. Results show that members of the order Methanococcales dominate at this <span class="hlt">site</span>, including mesophiles and hyper/thermophiles, but that some methanogens recovered from Marker 113 are surviving at low or sub-optimal hydrogen levels. <span class="hlt">Vent</span> 9m had a community composition similar to Marker 113, dominated by Methanococcales, and Zen Gardens, also at Axial, had a population of methanogens very different from either <span class="hlt">site</span>. The community there was composed of members of the order Methanomicrobiales, including mesophilic methanogens previously only found in terrestrial environments. Along the Mariana Arc, Shrimp City <span class="hlt">vent</span> at NW Rota-1 had some of the highest levels of methane detected on the entire arc, and mcrA analysis indicates members of the Methanococcales were present, as well as Methanosarcinales and anaerobic methane oxidizers. An integrated comparison of organismal and geochemical diversity will be presented to link energy transfer in these diverse <span class="hlt">hydrothermal</span> systems from mantle to microbes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013DSRI...75...93M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013DSRI...75...93M"><span id="translatedtitle">Megafaunal distribution and assessment of total methane and sulfide consumption by mussel beds at Menez Gwen <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>, based on geo-referenced photomosaics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marcon, Y.; Sahling, H.; Borowski, C.; dos Santos Ferreira, C.; Thal, J.; Bohrmann, G.</p> <p>2013-05-01</p> <p>The Menez Gwen <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, located on the flanks of a small young volcanic structure in the axial valley of the Menez Gwen seamount, are the shallowest known <span class="hlt">vent</span> systems on the Mid-Atlantic Ridge that host chemosynthetic communities. Although visited several times by research cruises, very few images have been published of the active <span class="hlt">sites</span>, and their spatial dimensions and morphologies remain difficult to comprehend. We visited the <span class="hlt">vents</span> on the eastern flank of the small Menez Gwen volcano during cruises with RV Poseidon (POS402, 2010) and RV Meteor (M82/3, 2010), and used new bathymetry and imagery data to provide first detailed information on the extents, surface morphologies, spatial patterns of the <span class="hlt">hydrothermal</span> discharge and the distribution of dominant megafauna of five active <span class="hlt">sites</span>. The investigated <span class="hlt">sites</span> were mostly covered by soft sediments and abundant white precipitates, and bordered by basaltic pillows. The <span class="hlt">hydrothermally</span>-influenced areas of the <span class="hlt">sites</span> ranged from 59 to 200 m2. Geo-referenced photomosaics and video data revealed that the symbiotic mussel Bathymodiolus azoricus was the dominant species and present at all <span class="hlt">sites</span>. Using literature data on average body sizes and biomasses of Menez Gwen B. azoricus, we estimated that the B. azoricus populations inhabiting the eastern flank <span class="hlt">sites</span> of the small volcano range between 28,640 and 50,120 individuals with a total biomass of 50 to 380 kg wet weight. Based on modeled rates of chemical consumption by the symbionts, the annual methane and sulfide consumption by B. azoricus could reach 1760 mol CH4 yr-1 and 11,060 mol H2S yr-1. We propose that the chemical consumption by B. azoricus over at the Menez Gwen <span class="hlt">sites</span> is low compared to the natural release of methane and sulfide via <span class="hlt">venting</span> fluids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013DSRI...82...73P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013DSRI...82...73P"><span id="translatedtitle">Genetic diversity of <span class="hlt">hydrothermal-vent</span> barnacles in 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>Plouviez, Sophie; Schultz, Thomas F.; McGinnis, Gwendolyn; Minshall, Halle; Rudder, Meghan; Van Dover, Cindy L.</p> <p>2013-12-01</p> <p>We evaluated mitochondrial cytochrome oxidase I genetic diversity of two barnacle species (Eochionelasmus ohtai manusensis, Vulcanolepas cf. parensis) at three <span class="hlt">sites</span> in Manus Basin (Solwara 1, South Su, Solwara 8). There was no evidence for within-<span class="hlt">site</span> or between-<span class="hlt">site</span> genetic differentiation for either species. While E. ohtai manusensis showed limited genetic variation, V. cf. parensis showed greater variation, with sequences distributed between two divergent groups. Assuming the cytochrome oxidase I gene is not under selection, significantly negative Tajima's D in E. ohtai manusensis is consistent with a recent population expansion due to a bottleneck or founder effect, whereas V. cf. parensis (combined groups) did not depart from a stable effective population size. Considering the groups separately, V. cf. parensis Group 1 (but not Group 2) showed a negative Tajima's D, indicating these groups may have encountered different historical demographic conditions. Data reported here are part of a baseline study against which recovery of genetic diversity following mineral extraction at Solwara 1 can be measured.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JGRB..11311101D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JGRB..11311101D"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> sediment alteration at a seafloor <span class="hlt">vent</span> field: Grimsey Graben, Tjrnes Fracture Zone, north of Iceland</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dekov, Vesselin; Scholten, Jan; Garbe-SchNberg, Carl-Dieter; Botz, Reiner; Cuadros, Javier; Schmidt, Mark; Stoffers, Peter</p> <p>2008-11-01</p> <p>An active seafloor <span class="hlt">hydrothermal</span> system subjects the background sediments of the Grimsey Graben (Tjrnes Fracture Zone) to alteration that produces dissolution of the primary volcaniclastic matrix and replacement/precipitation of sulfides, sulfates, oxides, oxyhydroxides, carbonates and phyllosilicates. Three types of <span class="hlt">hydrothermal</span> alteration of the sediment are defined on the basis of the dominant <span class="hlt">hydrothermal</span> phyllosilicate formed: smectite, kaolinite, chlorite. The most common alteration is near-total conversion of the volcaniclastic material to smectite (95-116C). The dominant smectite in the deepest sediments sampled is beidellite, which is replaced by montmorillonite and an intimate mixture of di- and tri-octahedral smectite up core. This gradual vertical change in smectite composition suggests an increase in the Mg supply upward, the result of sediment alteration by the ascending <span class="hlt">hydrothermal</span> fluids mixing with descending seawater. The vertical sequence kaolinite ? kaolinite-smectite mixed-layer ? smectite from bottom to top of a core, as well as the distinct zonation across the veins (kaolinite in the central zone ? kaolinite-smectite in the rim), suggests <span class="hlt">hydrothermal</span> transformation of the initially formed smectite to kaolinite through kaolinite-smectite mixed-layer (150-160C). The cause of this transformation might have been an evolution of the fluids toward a slightly acidic pH or a relative increase in the Al concentration. Minor amounts of chamosite fill thin veins in the deepest sections of some cores. The gradual change from background clinochlore to chamosite across the veins suggests that chamosite replaces clinochlore as Fe is made available from <span class="hlt">hydrothermal</span> dissolution of detrital Fe-containing minerals. The internal textures, REE distribution patterns and the mode of occurrence of another magnesian phyllosilicate, kerolite, suggest that this mineral is the primary precipitate in the <span class="hlt">hydrothermal</span> chimneys rather than an alteration product in the sediment. Kerolite precipitated after and grew on anhydrite in the chimneys. Oxygen isotope ratios are interpreted to reflect precipitation of kerolite at temperatures of 302 to 336C. It accumulated in the <span class="hlt">hydrothermal</span> mounds following the collapse of the chimneys and subsequent dissolution of anhydrite, thereby forming highly permeable aquifer layers underlying the <span class="hlt">vent</span> field. Some kerolite was redeposited in the near <span class="hlt">vent</span> field sediments by turbidity flows. The altered sediments are depleted in Mn, Rb and Sr, and enriched in U, Mo, Pb, Ba, As, Bi, Sb, Ag, Tl and Ga, as a result of leaching and precipitation, respectively. Conservative elements (Ti, Zr, Hf, Sc, Cr, Nb and Sn) are depleted or enriched in the altered sediments because of passive (precipitation or leaching of other phases) rather than active (because of their mobility) processes.</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://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://www.ncbi.nlm.nih.gov/pubmed/27169490','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27169490"><span id="translatedtitle">Bacterial and archaeal communities in the deep-sea sediments of inactive <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the Southwest India Ridge.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Likui; Kang, Manyu; Xu, Jiajun; Xu, Jian; Shuai, Yinjie; Zhou, Xiaojian; Yang, Zhihui; Ma, Kesen</p> <p>2016-01-01</p> <p>Active deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> harbor abundant thermophilic and hyperthermophilic microorganisms. However, microbial communities in inactive <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> have not been well documented. Here, we investigated bacterial and archaeal communities in the two deep-sea sediments (named as TVG4 and TVG11) collected from inactive <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the Southwest India Ridge using the high-throughput sequencing technology of Illumina MiSeq2500 platform. Based on the V4 region of 16S rRNA gene, sequence analysis showed that bacterial communities in the two samples were dominated by Proteobacteria, followed by Bacteroidetes, Actinobacteria and Firmicutes. Furthermore, archaeal communities in the two samples were dominated by Thaumarchaeota and Euryarchaeota. Comparative analysis showed that (i) TVG4 displayed the higher bacterial richness and lower archaeal richness than TVG11; (ii) the two samples had more divergence in archaeal communities than bacterial communities. Bacteria and archaea that are potentially associated with nitrogen, sulfur metal and methane cycling were detected in the two samples. Overall, we first provided a comparative picture of bacterial and archaeal communities and revealed their potentially ecological roles in the deep-sea environments of inactive <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the Southwest Indian Ridge, augmenting microbial communities in inactive <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. PMID:27169490</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4864381','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4864381"><span id="translatedtitle">Bacterial and archaeal communities in the deep-sea sediments of inactive <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the Southwest India 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>Zhang, Likui; Kang, Manyu; Xu, Jiajun; Xu, Jian; Shuai, Yinjie; Zhou, Xiaojian; Yang, Zhihui; Ma, Kesen</p> <p>2016-01-01</p> <p>Active deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> harbor abundant thermophilic and hyperthermophilic microorganisms. However, microbial communities in inactive <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> have not been well documented. Here, we investigated bacterial and archaeal communities in the two deep-sea sediments (named as TVG4 and TVG11) collected from inactive <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the Southwest India Ridge using the high-throughput sequencing technology of Illumina MiSeq2500 platform. Based on the V4 region of 16S rRNA gene, sequence analysis showed that bacterial communities in the two samples were dominated by Proteobacteria, followed by Bacteroidetes, Actinobacteria and Firmicutes. Furthermore, archaeal communities in the two samples were dominated by Thaumarchaeota and Euryarchaeota. Comparative analysis showed that (i) TVG4 displayed the higher bacterial richness and lower archaeal richness than TVG11; (ii) the two samples had more divergence in archaeal communities than bacterial communities. Bacteria and archaea that are potentially associated with nitrogen, sulfur metal and methane cycling were detected in the two samples. Overall, we first provided a comparative picture of bacterial and archaeal communities and revealed their potentially ecological roles in the deep-sea environments of inactive <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in the Southwest Indian Ridge, augmenting microbial communities in inactive <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. PMID:27169490</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 μM, and growth ceased below 17–23 μM 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://adsabs.harvard.edu/abs/2014AGUFM.V12B..07C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.V12B..07C"><span id="translatedtitle">Using the <span class="hlt">Vent</span>Cam and Optical Plume Velocimetry to Measure High-Temperature <span class="hlt">Hydrothermal</span> Fluid Flow Rates in the ASHES <span class="hlt">Vent</span> Field on Axial Volcano</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.; Mittelstaedt, E. L.; Fornari, D. J.</p> <p>2014-12-01</p> <p>Fluid flow rates through high-temperature mid-ocean ridge <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are likely quite sensitive to poroelastic forcing mechanisms such as tidal loading and tectonic activity. Because poroelastic deformation and flow perturbations are estimated to extend to considerable depths within young oceanic crust, observations of flow rate changes at seafloor <span class="hlt">vents</span> have the potential to provide constraints on the flow geometry and permeability structure of the underlying <span class="hlt">hydrothermal</span> systems, as well as the quantities of heat and chemicals they exchange with overlying ocean, and the potential biological productivity of ecosystems they host. To help provide flow rate measurements in these challenging environments, we have developed two new optical flow oriented technologies. The first is a new form of Optical Plume Velocimetry (OPV) which relies on single-frame temporal cross-correlation to obtain time-averaged image velocity fields from short video sequences. The second is the <span class="hlt">Vent</span>Cam, a deep sea camera system that can collect high-frame-rate video sequences at focused <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> suitable for analysis with OPV. During the July 2014 R/V Atlantis/Alvin expedition to Axial Seamount, we deployed the <span class="hlt">Vent</span>Cam at the ~300C Phoenix <span class="hlt">vent</span> within the ASHES <span class="hlt">vent</span> field and positioned it with DSRV Alvin. We collected 24 seconds of video at 50 frames per second every half-hour for approximately 10 days beginning July 22nd. We are currently applying single-frame lag OPV to these videos to estimate relative and absolute fluid flow rates through this <span class="hlt">vent</span>. To explore the relationship between focused and diffuse <span class="hlt">venting</span>, we deployed a second optical flow camera, the Diffuse Effluent Measurement System (DEMS), adjacent to this <span class="hlt">vent</span> at a fracture within the lava carapace where low-T (~30C) fluids were exiting. This system collected video sequences and diffuse flow measurements at overlapping time intervals. Here we present the preliminary results of our work with <span class="hlt">Vent</span>Cam and OPV, and comparisons with results from the DEMS camera.</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>2016-01-01</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://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://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://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://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/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 μM, 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> </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://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/2001ESASP.496..243J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001ESASP.496..243J"><span id="translatedtitle">The resistance to ionizing radiation of hyperthermophilic archaea isolated from 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>Jolivet, E.; L'Haridon, S.; Corre, E.; Gérard, E.; Myllykallio, H.; Forterre, P.; Prieur, D.</p> <p>2001-08-01</p> <p>In this paper we present many results on radioresistance of hyperthermophilic archaeon isolated from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Effects of gamma (γ) irradiation was first tested with Pyrococcus abyssi and showed that this micro-organism did not show any loss of viability until 2 kGy of γ-irradiation. Pulse Field Gel Electrophoresis (PFGE) analysis conducted with different species belonging to Archaea and Bacteria suggest that no specific DNA protection system exist that could explain the radioresistance of P. abyssi. Moreover, the genomic DNA completely fragmented after 2 kGy is fully restored in vivo under optimal growth conditions. The DNA replication or irradiated cells at 2,5 kGy is delayed by a lag phase which could coincide to this DNA repair. An associated mechanism of DNA repair by excision could act with the recombinational DNA repair. In parallel to these studies three hyperthermophilic archaeons highly resistant to ionizing radiation were isolated from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> after the enrichment cultures were submitted to elevated irradiation doses (up to 20 and 30 kGy). All these novel species were more radioresistant than P. abyssi.</p> </li> <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/2002AGUFM.V11C..12M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.V11C..12M"><span id="translatedtitle">Colonization by pioneer populations of ɛ-Proteobacteria and community succession at mid-ocean ridge <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> as determined by T-RFLP analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moyer, C. L.; Engebretson, J. J.</p> <p>2002-12-01</p> <p>Terminal-restriction fragment length polymorphism (T-RFLP) patterns were used to track populations of bacteria occurring within multiple bacterial growth chambers (BGCs) deployed at eight diffuse-flow (Tmax=78°C) <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> orifices located within the caldera of Axial Volcano, Juan de Fuca Ridge. For comparison, two distal diffuse <span class="hlt">vents</span> located at the Magic Mountain area on the Explorer Ridge were also examined. Over a five-year sampling period in conjunction with the NeMO (New Millennium Observatory) program, 52 BGCs were recovered after either a short-term (days) or long-term (annual) deployment. Upon recovery, genomic DNA was extracted and amplified using bacterial-specific PCR primers to generate 5' fluorescently-labeled amplicons of small subunit rRNA genes (i.e., SSU rDNAs). These PCR amplicons were digested with multiple tetrameric restriction endonucleases and the respective community diversity and succession patterns were characterized. The average number of populations (a measure of species richness) within the community that developed in short-term deployed BGCs was significantly lower than those detected in long-term deployed BGCs. All short-term BGC communities were dominated by primary colonizers or pioneer populations indicative of ɛ-Proteobacteria, of which, specific phylogenetic groups were recognized at <span class="hlt">vent</span> <span class="hlt">sites</span> throughout the five-year sampling period. The long-term BGCs showed evidence of successional events by an increased occurrence of numerous other populations accompanying the pioneer populations of ɛ-Proteobacteria. The discovery that all primary colonizing populations were most similar to known lineages of ɛ-Proteobacteria detected from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> located worldwide provides further evidence that a few cosmopolitan populations are capable of acting as the primary microbial successors of newly-formed <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/2003AGUFM.B12A0775F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.B12A0775F"><span id="translatedtitle">Long-Lived Serpentinization and Carbonate Precipitation at the Lost City <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>Frueh-Green, G. L.; Kelley, D. S.; Karson, J. A.; Bernasconi, S. M.; Proskurowski, G.; Ludwig, K. A.</p> <p>2003-12-01</p> <p>The discovery of spectacular, actively <span class="hlt">venting</span> carbonate chimneys at the Lost City <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field (LCHF) on the Atlantis Massif (MAR 30oN) has stimulated great interest in the role of serpentinization in driving <span class="hlt">hydrothermal</span> circulation in peridotite-hosted systems and in the biological communities that may be supported in these environments. The top of this fault-bounded, dome-like massif consists of variably deformed, talc-bearing serpentinites and gabbroic rocks ( ˜1.5 Ma), unconformably overlain by polymictic sedimentary breccias and bedded pelagic limestones or chalks that form a flat-lying carbonate cap. The limestones and matrix of the breccias consist of highly indurated foraminiferal sand with a well-preserved sub-tropical fauna, which were at least locally deposited before the last glacial maximum. Calcite and/or aragonite veins are abundant; fractures in the basement are filled by carbonate sediments and lithic fragments. Veining generally pre-dates sedimentary fracture-infilling. The youngest <span class="hlt">hydrothermal</span> phases include the LCHF chimneys and carbonate precipitates on outcrop surfaces, in cavities, and as growths protruding from fissures that are locally <span class="hlt">venting</span> fluids. Sr-, C- and O-isotope analyses and radiocarbon age-dating indicate that this system is the integrated effect of tectonic activity, serpentinization, and <span class="hlt">hydrothermal</span> flow that has lasted at least 30,000 years. C- and O-isotope compositions indicate a range of precipitation temperatures from ambient conditions up to ˜ 250oC at depth and reflect mixing of seawater and serpentinization-derived <span class="hlt">hydrothermal</span> fluids. Analyses of separated fractions of sedimentary and <span class="hlt">hydrothermal</span> components define a sedimentary end-member composition of δ 13C = 1.3 +/- 0.3 and δ 18O = 1.5 +/- 0.5‰ (VPDB) and a <span class="hlt">hydrothermal</span> end-member composition of δ 13C = 3.3 and δ 18O = 5‰ . Based on the present-day degree of serpentinization, the geophysical structure and age of the lithosphere at the Atlantis Massif, and the radiocarbon ages, we estimate a minimum rate of serpentinization of 1.2 ṡ 10-4}km{3/y. Our field observations together with available gravity and seismic data indicate that a considerable proportion of the massif is relatively unaltered peridotite. The access of seawater to relatively cool, fresh peridotite, coupled with faulting, volumetric expansion and mass wasting processes are crucial to sustain such systems. In addition, diffusely percolating, high pH fluids emanating from the underlying serpentinites promote rapid sediment lithification, which offers an efficient mechanism for slowing heat loss and maintaining higher temperatures in the basement. Collectively these processes have the potential to prolong <span class="hlt">hydrothermal</span> activity for tens of thousands of years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23663201','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23663201"><span id="translatedtitle">Nuclear mitochondrial pseudogenes in Austinograea alayseae <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> crabs (Crustacea: Bythograeidae): effects on DNA barcoding.</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; Lee, Kyeong Yong; Ju, Se-Jong</p> <p>2013-09-01</p> <p>Members of the brachyuran crab family, Bythograeidae, are among the most abundant and common crabs in <span class="hlt">vent</span> fields. However, their identification based on morphological characteristics often leads to incorrect species recognition due to a lack of taxonomic factors and the existence of sibling (or cryptic) species. For these reasons, we used DNA barcoding for <span class="hlt">vent</span> crabs using mitochondrial cytochrome c oxidase subunit 1 (CO1). However, several nuclear mitochondrial pseudogenes (Numts) were amplified from Austinograea alayseae Guinot, 1990, using universal primers (Folmer primers). The Numts were characterized in six haplotypes, with 13.58-14.11% sequence divergence from A. alayseae, a higher nonsynonymous substitution ratio than true CO1, and the formation of an independent clade in bythograeids. In a neighbour-joining tree, the origin of the Numts would be expected to incorporate into the nucleus at an ancestral node of Austinograea, and they mutated more slowly in the nucleus than CO1 in the mitochondria. This evolutionary process may have resulted in the higher binding affinity of Numts for the Folmer primers than CO1. In the present study, we performed long PCR for the amplification of CO1 in A. alayseae. We also present evidence that Numts can introduce serious ambiguity into DNA barcoding, including overestimating the number of species in bythograeids. These results may help in conducting taxonomic studies using mitochondrial genes from organisms living in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields. PMID:23663201</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://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/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 ATPsα 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 ΦST'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://adsabs.harvard.edu/abs/2011AGUFM.V11E2542R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.V11E2542R"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> flow at Main Endeavour Field imaged and measured with Cable Operated <span class="hlt">Vent</span> Imaging Sonar</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rona, P. A.; Bemis, K. G.; Xu, G.; Jackson, D. R.; Jones, C. D.</p> <p>2011-12-01</p> <p>Initial acoustic monitoring of <span class="hlt">hydrothermal</span> flow in the Main Endeavour Field (MEF) captures the spatial distribution of diffuse and focused discharge and shows potential for flux determinations. Our Cabled Observatory <span class="hlt">Vent</span> Imaging Sonar (COVIS) was connected to the NEPTUNE Canada Endeavour Observatory in September 2010. Using a customized Reson 7125 multi-beam sonar, COVIS acquired a 29 day time series of black smoker plume and associated diffuse <span class="hlt">hydrothermal</span> flow from Grotto, a 30 m diameter <span class="hlt">vent</span> cluster in the MEF, Juan de Fuca Ridge. Detection of the spatial patterns of diffuse flow utilizes phase decorrelation of the acoustic signal (200kHz) by buoyancy-driven turbulence (acoustic scintillation) to produce a time series of maps. Substantial fluctuation in the detected diffuse flow area (0.1 - 18 m^2) was observed over the 29 days of observation, although position remained stable. Acoustic imaging of focused flow (400 kHz) utilizes high volume backscatter (attributed to particles and turbulent sound speed fluctuations) to image in 3D the initial tens of meters of rise of buoyant plumes. Spectral analysis of bending inclination of a strong plume from multiple fast smokers on the NW end of Grotto (north tower) indicates that the dominant modes correspond with the ambient mixed semi-diurnal tide (based on current meter data at a mooring 2.9 km to the north and on a tidal model), with at least one secondary mode attributable to sub-inertial flow related to inflow to the axial valley. A weaker plume from several slower smokers is present on the NE end of Grotto. On first analysis, the bending inclination of the weaker plume appears to be affected by the stronger plume. Quantification of flow velocity and volume flux of plumes begins with measuring the Doppler phase shift through plume cross-sections beginning at 5 m above source <span class="hlt">vents</span> where discharge merges. The volume flux measurements enable calculation of entrainment coefficients, which prior work on the same strong plume indicated increase with degree of bending. The acoustic data in concert with in situ measurements support inversions to obtain fluxes to elucidate the role of <span class="hlt">hydrothermal</span> flow in transfer of heat, chemicals and biological material from the crust to the ocean. We are exploring the feasibility of fitting plume models to Doppler velocity data in order to estimate heat flux. Ongoing analysis pursues quantification of fluid flux from diffuse and focused flow. In addition, the time series provide observations of <span class="hlt">hydrothermal</span> flow response to tidal, tectonic and volcanic forcing on time scales from hours potentially to years. (Work supported by NSF Grants Nos. OCE-0824612 and OCE-0825088)</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.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3105715','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3105715"><span id="translatedtitle">Comparative metagenomics of microbial communities inhabiting deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimneys with contrasting chemistries</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, Wei; Wang, Fengping; Guo, Lei; Chen, Zeling; Sievert, Stefan M; Meng, Jun; Huang, Guangrui; Li, Yuxin; Yan, Qingyu; Wu, Shan; Wang, Xin; Chen, Shangwu; He, Guangyuan; Xiao, Xiang; Xu, Anlong</p> <p>2011-01-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimneys harbor a high diversity of largely unknown microorganisms. Although the phylogenetic diversity of these microorganisms has been described previously, the adaptation and metabolic potential of the microbial communities is only beginning to be revealed. A pyrosequencing approach was used to directly obtain sequences from a fosmid library constructed from a black smoker chimney 4143-1 in the Mothra <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field at the Juan de Fuca Ridge. A total of 308 034 reads with an average sequence length of 227 bp were generated. Comparative genomic analyses of metagenomes from a variety of environments by two-way clustering of samples and functional gene categories demonstrated that the 4143-1 metagenome clustered most closely with that from a carbonate chimney from Lost City. Both are highly enriched in genes for mismatch repair and homologous recombination, suggesting that the microbial communities have evolved extensive DNA repair systems to cope with the extreme conditions that have potential deleterious effects on the genomes. As previously reported for the Lost City microbiome, the metagenome of chimney 4143-1 exhibited a high proportion of transposases, implying that horizontal gene transfer may be a common occurrence in the deep-sea <span class="hlt">vent</span> chimney biosphere. In addition, genes for chemotaxis and flagellar assembly were highly enriched in the chimney metagenomes, reflecting the adaptation of the organisms to the highly dynamic conditions present within the chimney walls. Reconstruction of the metabolic pathways revealed that the microbial community in the wall of chimney 4143-1 was mainly fueled by sulfur oxidation, putatively coupled to nitrate reduction to perform inorganic carbon fixation through the Calvin–Benson–Bassham cycle. On the basis of the genomic organization of the key genes of the carbon fixation and sulfur oxidation pathways contained in the large genomic fragments, both obligate and facultative autotrophs appear to be present and contribute to biomass production. PMID:20927138</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> <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://www.ncbi.nlm.nih.gov/pubmed/27101410','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27101410"><span id="translatedtitle">Development of an ecotoxicological protocol for the deep-sea fauna using 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>Auguste, M; Mestre, N C; Rocha, T L; Cardoso, C; Cueff-Gauchard, V; Le Bloa, S; Cambon-Bonavita, M A; Shillito, B; Zbinden, M; Ravaux, J; Bebianno, M J</p> <p>2016-06-01</p> <p>In light of deep-sea mining industry development, particularly interested in massive-sulphide deposits enriched in metals with high commercial value, efforts are increasing to better understand potential environmental impacts to local fauna. The aim of this study was to assess the natural background levels of biomarkers in the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> shrimp Rimicaris exoculata and their responses to copper exposure at in situ pressure (30MPa) as well as the effects of depressurization and pressurization of the high-pressure aquarium IPOCAMP. R. exoculata were collected from the chimney walls of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">site</span> TAG (Mid Atlantic Ridge) at 3630m depth during the BICOSE cruise in 2014. Tissue metal accumulation was quantified in different tissues (gills, hepatopancreas and muscle) and a battery of biomarkers was measured: metal exposure (metallothioneins), oxidative stress (catalase, superoxide dismutase, glutathione-S-transferase and glutathione peroxidase) and oxidative damage (lipid peroxidation). Data show a higher concentration of Cu in the hepatopancreas and a slight increase in the gills after incubations (for both exposed groups). Significant induction of metallothioneins was observed in the gills of shrimps exposed to 4μM of Cu compared to the control group. Moreover, activities of enzymes were detected for the in situ group, showing a background protection against metal toxicity. Results suggest that the proposed method, including a physiologically critical step of pressurizing and depressurizing the test chamber to enable the seawater exchange during exposure to contaminants, is not affecting metal accumulation and biomarkers response and may prove a useful method to assess toxicity of contaminants in deep-sea species. PMID:27101410</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26934591','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26934591"><span id="translatedtitle">Bacterial Community Associated with Organs of Shallow <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Crab Xenograpsus testudinatus near Kuishan Island, Taiwan.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yang, Shan-Hua; Chiang, Pei-Wen; Hsu, Tin-Chang; Kao, Shuh-Ji; Tang, Sen-Lin</p> <p>2016-01-01</p> <p>Shallow-water <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> off Kueishan Island (northeastern Taiwan) provide a unique, sulfur-rich, highly acidic (pH 1.75-4.6) and variable-temperature environment. In this species-poor habitat, the crab Xenograpsus testudinatus is dominant, as it mainly feeds on zooplankton killed by sulfurous plumes. In this study, 16S ribosomal RNA gene amplicon pyrosequencing was used to investigate diversity and composition of bacteria residing in digestive gland, gill, stomach, heart, and mid-gut of X. testudinatus, as well as in surrounding seawater. Dominant bacteria were Gamma- and Epsilonproteobacteria that might be capable of autotrophic growth by oxidizing reduced sulfur compounds and are usually resident in deep-sea <span class="hlt">hydrothermal</span> systems. Dominant bacterial OTUs in X. testudinatus had both host and potential organ specificities, consistent with a potential trophic symbiotic relationship (nutrient transfer between host and bacteria). We inferred that versatile ways to obtain nutrients may provide an adaptive advantage for X. testudinatus in this demanding environment. To our knowledge, this is the first study of bacterial communities in various organs/tissues of a crustacean in a shallow-water <span class="hlt">hydrothermal</span> system, and as such, may be a convenient animal model for studying these systems. PMID:26934591</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4774926','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4774926"><span id="translatedtitle">Bacterial Community Associated with Organs of Shallow <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Crab Xenograpsus testudinatus near Kuishan Island, Taiwan</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yang, Shan-Hua; Chiang, Pei-Wen; Hsu, Tin-Chang; Kao, Shuh-Ji; Tang, Sen-Lin</p> <p>2016-01-01</p> <p>Shallow-water <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> off Kueishan Island (northeastern Taiwan) provide a unique, sulfur-rich, highly acidic (pH 1.75–4.6) and variable-temperature environment. In this species-poor habitat, the crab Xenograpsus testudinatus is dominant, as it mainly feeds on zooplankton killed by sulfurous plumes. In this study, 16S ribosomal RNA gene amplicon pyrosequencing was used to investigate diversity and composition of bacteria residing in digestive gland, gill, stomach, heart, and mid-gut of X. testudinatus, as well as in surrounding seawater. Dominant bacteria were Gamma- and Epsilonproteobacteria that might be capable of autotrophic growth by oxidizing reduced sulfur compounds and are usually resident in deep-sea <span class="hlt">hydrothermal</span> systems. Dominant bacterial OTUs in X. testudinatus had both host and potential organ specificities, consistent with a potential trophic symbiotic relationship (nutrient transfer between host and bacteria). We inferred that versatile ways to obtain nutrients may provide an adaptive advantage for X. testudinatus in this demanding environment. To our knowledge, this is the first study of bacterial communities in various organs/tissues of a crustacean in a shallow-water <span class="hlt">hydrothermal</span> system, and as such, may be a convenient animal model for studying these systems. PMID:26934591</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://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://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> </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://www.ncbi.nlm.nih.gov/pubmed/26941137','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26941137"><span id="translatedtitle">Draft Genome Sequence of Psychrobacter piscatorii Strain LQ58, a Psychrotolerant 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=pubmed">PubMed</a></p> <p>Zhou, Meixian; Dong, Binbin; Liu, Qing</p> <p>2016-01-01</p> <p>Here, we report the 3.1-Mb draft genome sequence of Psychrobacter piscatorii strain LQ58, isolated from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> on the East Pacific Rise. The sequence will provide further insight into the environmental adaptation of psychrotolerant bacteria and the development of novel cold-active enzymes for industrial application. PMID:26941137</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4777748','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4777748"><span id="translatedtitle">Draft Genome Sequence of Psychrobacter piscatorii Strain LQ58, a Psychrotolerant 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>Dong, Binbin; Liu, Qing</p> <p>2016-01-01</p> <p>Here, we report the 3.1-Mb draft genome sequence of Psychrobacter piscatorii strain LQ58, isolated from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> on the East Pacific Rise. The sequence will provide further insight into the environmental adaptation of psychrotolerant bacteria and the development of novel cold-active enzymes for industrial application. PMID:26941137</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26679595','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26679595"><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=pubmed">PubMed</a></p> <p>Zhou, Meixian; 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://www.ncbi.nlm.nih.gov/pubmed/10858584','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/10858584"><span id="translatedtitle">High incidence of halotolerant bacteria in Pacific <span class="hlt">hydrothermal-vent</span> and pelagic environments.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kaye; Baross</p> <p>2000-06-01</p> <p>The abundance of halotolerant microorganisms in <span class="hlt">hydrothermal-vent</span> and pelagic waters in the North and South Pacific was estimated by the most probable number (MPN) technique using a heterotrophic 16% NaCl medium incubated at 20-24 degrees C. Based on these MPNs and direct counts with epifluorescence microscopy to enumerate the total microbial population, salt-tolerant microbes comprised from <0.01 to >28% of the total microbial community. Fourteen isolates from these MPN enrichments were identified by sequencing a portion of the 16S rRNA gene, and all were found to belong to the genera Halomonas and Marinobacter. The response to salt of mesophilic <span class="hlt">hydrothermal-vent</span> microbial isolates obtained without selecting for salt tolerance was also examined. Forty-one of 65 strains cultured from <span class="hlt">hydrothermal</span> plume waters, low-temperature <span class="hlt">hydrothermal</span> fluids, sulfide rock and an animal specimen at approximately 2000-2200 m depth from the Endeavour Segment of the Juan de Fuca Ridge were subjected to increasing concentrations of NaCl, and over half grew at a NaCl concentration that is lethal to many commonly isolated marine bacteria. At least 36 of the 65 isolates (>/=55%) grew in the enrichment medium supplemented with 10% NaCl; at least 30 of 65 (>/=46%) grew with 16% NaCl; at least 20 of 65 (>/=31%) tolerated 22% NaCl. Based on phylogenetic analysis of the 16S rRNA gene in nine of these 65 isolates, four belonged to the genus Halomonas. These Halomonas strains tolerated 22-27% NaCl. It is possible that a majority of the other 16 isolates which grew with 22% NaCl are also Halomonas based on their degree of halotolerance, morphology, and apparent abundance as revealed by MPN enrichments. The four Halomonas strains obtained without selecting for halotolerance were further characterized physiologically and metabolically. Overall, they grew between -1 degrees C and 40 degrees C, were facultative aerobes, oxidized between 49 and 70 organic compounds according to Biolog plate substrate utilization matrices, grew with oligotrophic quantities of carbon (0.002% yeast extract) in liquid media, reduced nitrate to nitrite, and tolerated up to 0.05-3 mM Cd(2+). Halomonas is one of the most abundant culturable organisms in the ocean, and its success may be attributed to its metabolic and physiological versatility. PMID:10858584</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.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/2001Natur.412..145K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001Natur.412..145K"><span id="translatedtitle">An off-axis <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field near the Mid-Atlantic Ridge at 30° N</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kelley, Deborah S.; Karson, Jeffrey A.; Blackman, Donna K.; Früh-Green, Gretchen L.; Butterfield, David A.; Lilley, Marvin D.; Olson, Eric J.; Schrenk, Matthew O.; Roe, Kevin K.; Lebon, Geoff T.; Rivizzigno, Pete; AT3-60 Shipboard Party, a2</p> <p>2001-07-01</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°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 15km 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°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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15967984','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15967984"><span id="translatedtitle">An obligately photosynthetic bacterial anaerobe 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>Beatty, J Thomas; Overmann, Jörg; Lince, Michael T; Manske, Ann K; Lang, Andrew S; Blankenship, Robert E; Van Dover, Cindy L; Martinson, Tracey A; Plumley, F Gerald</p> <p>2005-06-28</p> <p>The abundance of life on Earth is almost entirely due to biological photosynthesis, which depends on light energy. The source of light in natural habitats has heretofore been thought to be the sun, thus restricting photosynthesis to solar photic environments on the surface of the Earth. If photosynthesis could take place in geothermally illuminated environments, it would increase the diversity of photosynthetic habitats both on Earth and on other worlds that have been proposed to possibly harbor life. Green sulfur bacteria are anaerobes that require light for growth by the oxidation of sulfur compounds to reduce CO2 to organic carbon, and are capable of photosynthetic growth at extremely low light intensities. We describe the isolation and cultivation of a previously unknown green sulfur bacterial species from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span>, where the only source of light is geothermal radiation that includes wavelengths absorbed by photosynthetic pigments of this organism. PMID:15967984</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2808221','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2808221"><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.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Yao, Haimin; Dao, Ming; Imholt, Timothy; Huang, Jamie; Wheeler, Kevin; Bonilla, Alejandro; Suresh, Subra; Ortiz, Christine</p> <p>2010-01-01</p> <p>Biological exoskeletons, in particular those with unusually robust and multifunctional properties, hold enormous potential for the development of improved load-bearing and protective engineering materials. Here, we report new materials and mechanical design principles of the iron-plated multilayered structure of the natural armor of Crysomallon squamiferum, a recently discovered gastropod mollusc from the Kairei Indian <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field, which is unlike any other known natural or synthetic engineered armor. We have determined through nanoscale experiments and computational simulations of a predatory attack that the specific combination of different materials, microstructures, interfacial geometries, gradation, and layering are advantageous for penetration resistance, energy dissipation, mitigation of fracture and crack arrest, reduction of back deflections, and resistance to bending and tensile loads. The structure-property-performance relationships described are expected to be of technological interest for a variety of civilian and defense applications. PMID:20133823</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009DSRII..56.1665R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009DSRII..56.1665R"><span id="translatedtitle">Phylogenetic diversity of methanogenic, sulfate-reducing and methanotrophic prokaryotes from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> and cold seeps</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reed, Andrew J.; Dorn, Ruth; Van Dover, Cindy L.; Lutz, Richard A.; Vetriani, Costantino</p> <p>2009-09-01</p> <p>Microbial communities of methanogenic, sulfate-reducing and methanotrophic prokaryotes from deep-sea environments were investigated by molecular phylogenetic analysis of the deduced amino acid sequences of the genes encoding for the methyl coenzyme M reductase ( mcrA), dissimilatory sulfite reductase ( dsrAB) and particulate methane monoxygenase ( pmoA), respectively. Clone libraries of PCR amplified genes were constructed using DNA extracted from deep-sea <span class="hlt">vent</span> chimneys (Rainbow and Logatchev <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields, Mid-Atlantic Ridge, Atlantic Ocean; 9°N East Pacific Rise, Pacific Ocean) and from vertically subsampled sediment cores from cold-seep areas (Blake Ridge, western Atlantic Ocean; Florida Escarpment, Gulf of Mexico). Recombinant clones were screened by RFLP and representative dsrAB, mcrA and pmoA genes were sequenced. The dsrAB sequences grouped primarily within the orders Desulfobacterales, Syntrophobacterales and the Gram-positive order Clostridales. Cold-seep mcrA sequences were distributed among the ANME-2c, -2d and -2e groups, which were previously shown to be associated with the anaerobic oxidation of methane. This study also reports the first mcrA sequences from a high-temperature, black smoker chimney (Logatchev) to group within the ANME-2e subgroup. The majority of the remaining <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> mcrA sequences were primarily related to thermophilic members of the anaerobic, methanogenic order Methanococcales. A shift in the dominant ANME-2 group with depth in the sediment for both Florida Escarpment and Blake Ridge mcrA libraries was detected. ANME-2d related clones were detected in the top zones of both cores, with the frequency of ANME-2e related clones increasing with depth. All pmoA sequences retrieved from the cold-seep <span class="hlt">sites</span> were found to be related to Type I methanotrophic members of the γ-proteobacteria, and were primarily distributed among three major clusters of sequences. No Type II pmoA sequences related to methanotrophic members of the α-proteobacteria were detected, suggesting that the methanotrophic communities in these cold-seep areas are dominated by Type I γ-proteobacteria.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.P12A..07L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.P12A..07L"><span id="translatedtitle">Mineralized iron oxidizing bacteria from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>: targeting biosignatures 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>Leveille, R. J.</p> <p>2010-12-01</p> <p>Putative <span class="hlt">hydrothermal</span> systems have been identified on Mars based on orbital imagery and rover-based analyses. Based on Earth analogs, <span class="hlt">hydrothermal</span> systems on Mars would be highly attractive for their potential for preserving organic and inorganic biosignatures. For example, iron oxidizing bacteria are ubiquitous in marine and terrestrial <span class="hlt">hydrothermal</span> systems, where they often display distinctive cell morphologies and are commonly encrusted by minerals, especially bacteriogenic iron oxides and silica. Microfossils of iron oxidizing bacteria have been found in ancient Si-Fe deposits and iron oxidation may be an ancient and widespread metabolic pathway. In order to investigate mineralized iron oxidizing bacteria as a biosignature, we have examined samples collected from extinct <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> along Explorer Ridge, NE Pacific Ocean. In addition, microaerophilic iron oxidizing bacteria, isolated from active Pacific <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, were grown in a Fe-enriched seawater medium at constant pH (6.5) and O2 concentration (5%) in a controlled bioreactor system. Samples and experimental products were examined with a combination of variable-pressure and field-emission scanning electron microscopy (SEM), in some cases by preparing samples with a focused ion beam (FIB) milling system. Light-toned seafloor samples display abundant filamentous forms resembling, in both size and shape (1-5 microns in diameter and up to several microns in length), the twisted stalks of Gallionella and the elongated filaments of Leptothrix. Some samples consist entirely of low-density masses of silica (>90% Si) encrusted filamentous forms. The presence of unmineralized filamentous matter rich in C and Fe suggests that these are the remains of iron oxidizing bacteria. Mineralized filaments sectioned by FIB show variable internal material within semi-hollow, tubular-like features. Silica encrustations also show pseudo-concentric growth bands. In the bioreactor runs, abundant microbial growth and formation of an iron oxyhydroxide precipitate, either in direct association with the cells or within the growth medium, were observed. Preliminary analyses suggest that these precipitates are different from abiotic precipitates. Continuing work includes high-resolution TEM observations of cultured organisms and biogenic iron minerals, Raman and reflectance spectroscopy of precipitates, examination of seafloor incubation experiments, and bioreactor silicification experiments in order to better understand the Fe-Si fossilization process. Microaerophilic iron oxidation could have existed on the early Earth in environments containing small amounts of oxygen produced either by locally-concentrated photosynthetic microorganisms (e.g., cyanobacteria) or by chemical reactions. By analogy, similar subsurface or near-surface microaerophilic environments could have existed on Mars in the past, including in low-temperature <span class="hlt">hydrothermal</span> systems. The distinctive morphologies and Fe-Si mineralization patterns of iron oxidizing bacteria could be a useful biosignature to search for on Mars. Deposits and features similar to those described here could be identified on Mars with existing technologies, and thus <span class="hlt">hydrothermal</span> systems represent an attractive target for future surface and sample return missions.</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> <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://www.ncbi.nlm.nih.gov/pubmed/23665957','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23665957"><span id="translatedtitle">Photoprotective bioactivity present in a unique marine bacteria collection from Portuguese 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>Martins, Ana; Tenreiro, Tania; Andrade, Gonalo; Gadanho, Mrio; Chaves, Sandra; Abrantes, Marta; Calado, Patrcia; Tenreiro, Rogrio; Vieira, Helena</p> <p>2013-05-01</p> <p>Interesting biological activities have been found for numerous marine compounds. In fact, screening of phylogenetically diverse marine microorganisms from extreme environments revealed to be a rational approach for the discovery of novel molecules with relevant bioactivities for industries such as pharmaceutical and cosmeceutical. Nevertheless, marine sources deliverables are still far from the expectations and new extreme sources of microbes should be explored. In this work, a marine prokaryotic collection from four Mid-Atlantic Ridge (MAR) deep sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> near the Azores Islands, Portugal, was created, characterized and tested for its photoprotective capacity. Within 246 isolates, a polyphasic approach, using chemotaxonomic and molecular typing methods, identified 23-related clusters of phenetically similar isolates with high indexes of diversity. Interestingly, 16S rRNA gene sequencing suggested the presence of 43% new prokaryotic species. A sub-set of 139 isolates of the prokaryotic collection was selected for biotechnological exploitation with 484 bacterial extracts prepared in a sustainable upscalling manner. 22% of the extracts showed an industrially relevant photoprotective activity, with two extracts, belonging to new strains of the species Shewanella algae and Vibrio fluvialis, uniquely showing UV-A, UV-B and UV-C protective capacity. This clearly demonstrates the high potential of the bacteria MAR <span class="hlt">vents</span> collection in natural product synthesis with market applications. PMID:23665957</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; Compre, Philippe; Martinez, Isabelle; Guyot, Franois; Gaill, Franoise</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://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3988086','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3988086"><span id="translatedtitle">Exopolysaccharides Isolated from <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Bacteria Can Modulate the Complement System</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Courtois, Anthony; Berthou, Christian; Guézennec, Jean</p> <p>2014-01-01</p> <p>The complement system is involved in the defence against bacterial infection, or in the elimination of tumour cells. However, disturbances in this system contributes to the pathogenesis of various inflammatory diseases. The efficiency of therapeutic anti-tumour antibodies is enhanced when the complement system is stimulated. In contrast, cancer cells are able to inhibit the complement system and thus proliferate. Some marine molecules are currently being developed as new drugs for use in humans. Among them, known exopolyssacharides (EPSs) generally originate from fungi, but few studies have been performed on bacterial EPSs and even fewer on EPSs extracted from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> microbes. For use in humans, these high molecular weight EPSs must be depolymerised. Furthermore, the over-sulphation of EPSs can modify their biological activity. The aim of this study was to investigate the immunodulation of the complement system by either native or over-sulphated low molecular weight EPSs isolated from <span class="hlt">vent</span> bacteria in order to find pro or anti-activators of complement. PMID:24736648</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3707158','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3707158"><span id="translatedtitle">Photoprotective Bioactivity Present in a Unique Marine Bacteria Collection from Portuguese 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>Martins, Ana; Tenreiro, Tania; Andrade, Gonçalo; Gadanho, Mário; Chaves, Sandra; Abrantes, Marta; Calado, Patrícia; Tenreiro, Rogério; Vieira, Helena</p> <p>2013-01-01</p> <p>Interesting biological activities have been found for numerous marine compounds. In fact, screening of phylogenetically diverse marine microorganisms from extreme environments revealed to be a rational approach for the discovery of novel molecules with relevant bioactivities for industries such as pharmaceutical and cosmeceutical. Nevertheless, marine sources deliverables are still far from the expectations and new extreme sources of microbes should be explored. In this work, a marine prokaryotic collection from four Mid-Atlantic Ridge (MAR) deep sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> near the Azores Islands, Portugal, was created, characterized and tested for its photoprotective capacity. Within 246 isolates, a polyphasic approach, using chemotaxonomic and molecular typing methods, identified 23-related clusters of phenetically similar isolates with high indexes of diversity. Interestingly, 16S rRNA gene sequencing suggested the presence of 43% new prokaryotic species. A sub-set of 139 isolates of the prokaryotic collection was selected for biotechnological exploitation with 484 bacterial extracts prepared in a sustainable upscalling manner. 22% of the extracts showed an industrially relevant photoprotective activity, with two extracts, belonging to new strains of the species Shewanella algae and Vibrio fluvialis, uniquely showing UV-A, UV-B and UV-C protective capacity. This clearly demonstrates the high potential of the bacteria MAR <span class="hlt">vents</span> collection in natural product synthesis with market applications. PMID:23665957</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5108416','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5108416"><span id="translatedtitle">Distribution and composition of <span class="hlt">hydrothermal</span> plume particles from the ASHES <span class="hlt">vent</span> field at Axial Volcano, Juan de Fuca Ridge. [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>Feely, R.A.; Geiselman, T.L.; Baker, E.T.; Massoth, G.J. ); Hammond, S.R. )</p> <p>1990-08-10</p> <p>In 1986 and 1987, buoyant and neutrally buoyant <span class="hlt">hydrothermal</span> plume particles from the ASHES <span class="hlt">vent</span> field within Axial Volcano were sampled to study their variations in composition with height above the seafloor. Individual mineral phases were identified using standard X ray diffraction procedures. Elemental composition and particle morphologies were determined by X ray fluorescence spectrometry and scanning electron microscopy/X ray energy spectrometry techniques. The <span class="hlt">vent</span> particles were primarily composed of sphalerite, anhydrite, pyrite, pyrrhotite, chalcopyrite, barite, hydrous iron oxides, and amorphous silica. Grain size analyses of buoyant plume particles showed rapid particle growth in the first few centimeters above the <span class="hlt">vent</span> orifice, followed by differential sedimentation of the larger sulfide and sulfate minerals out of the buoyant plume. The neutrally buoyant plume consisted of a lower plume, which was highly enriched in Fe, S, Zn, and Cu, and an upper plume, which was highly enriched in Fe and Mn. The upper plume was enriched in Fe and Mn oxyhydroxide particles, and the lower plume was enriched in suspended sulfide particles in addition to the Fe and Mn oxyhydroxide particles. The chemical data for the water column particles indicate that chemical scavenging and differential sedimentation processes are major factors controlling the composition of the dispersing <span class="hlt">hydrothermal</span> particles. Short-term sediment trap experiments indicate that the fallout from the ASHES <span class="hlt">vent</span> field is not as large as some of the other <span class="hlt">vent</span> fields on the Juan de Fuca Ridge.</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> </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://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://adsabs.harvard.edu/abs/2009DSRI...56.2065S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009DSRI...56.2065S"><span id="translatedtitle">A dual sensor device to estimate fluid flow velocity at diffuse <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>Sarrazin, J.; Rodier, P.; Tivey, M. K.; Singh, H.; Schultz, A.; Sarradin, P. M.</p> <p>2009-11-01</p> <p>Numerous attempts have been made over the last thirty years to estimate fluid flow rates at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, either at the exit of black smoker chimneys or within diffuse flow areas. In this study, we combine two methods to accurately estimate fluid flow velocities at diffuse flow areas. While the first method uses a hot film anemometer that performs high-frequency measurements, the second allows a relatively rapid assessment of fluid flow velocity through video imagery and provides in situ data to calibrate the sensor. Measurements of flow velocities on <span class="hlt">hydrothermal</span> diffuse flow areas were obtained on the Mid-Atlantic Ridge (MAR). They range from 1.1 to 4.9 mm/s at the substratum level, in low-temperature (4.5-16.4 °C) diffuse flow areas from the Tour Eiffel sulfide edifice. A strong correlation was observed between fluid flow velocities and temperature, supporting the possible use of temperature as a proxy to estimate the flow rates in diffuse flow areas where such a simple linear flow/temperature relation is shown to dominate.</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 δ3He = 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 (δ3He = 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 δ3He = 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.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.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=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/2016GML....36...15C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GML....36...15C"><span id="translatedtitle">Influence of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> on water column properties in the crater of the Kolumbo submarine volcano, Santorini volcanic field (Greece)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Christopoulou, Maria E.; Mertzimekis, Theo J.; Nomikou, Paraskevi; Papanikolaou, Dimitrios; Carey, Steven; Mandalakis, Manolis</p> <p>2016-02-01</p> <p>The Kolumbo submarine volcano, located 7 km northeast of the island of Santorini, is part of Santorini's volcanic complex in the south Aegean Sea, Greece. Kolumbo's last eruption was in 1650 AD. However, a unique and active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field has been revealed in the northern part of its crater floor during an oceanographic survey by remotely operated vehicles (ROVs) in 2006. In the present study, conductivity-temperature-depth (CTD) data collected by ROV Hercules during three oceanographic surveys onboard E/V Nautilus in 2010 and 2011 have served to investigate the distribution of physicochemical properties in the water column, as well as their behavior directly over the <span class="hlt">hydrothermal</span> field. Additional CTD measurements were carried out in volcanic cone 3 (VC3) along the same volcanic chain but located 3 km northeast of Kolumbo where no <span class="hlt">hydrothermal</span> activity has been detected to date. CTD profiles exhibit pronounced anomalies directly above the active <span class="hlt">vents</span> on Kolumbo's crater floor. In contrast, VC3 data revealed no such anomalies, essentially resembling open-sea (background) conditions. Steep increases of temperature (e.g., from 16 to 19 °C) and conductivity near the maximum depth (504 m) inside Kolumbo's cone show marked spatiotemporal correlation. Vertical distributions of CTD signatures suggest a strong connection to Kolumbo's morphology, with four distinct zones identified (open sea, turbid flow, invariable state, <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field). Additionally, overlaying the near-seafloor temperature measurements on an X-Y coordinate grid generates a detailed 2D distribution of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field and clarifies the influence of fluid discharges in its formation.</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, 230-650 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 4S and the other in a segment centre characterised by very fresh sheet-flows near 5S. 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/2008AGUFM.B51D0403S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.B51D0403S"><span id="translatedtitle">Towards a Genome-Enabled Sensor for In Situ Monitoring of Microbial Communities in <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>Shi, X.; Wu, J.; Gao, W.; Chao, S.; Zhang, W.; Meldrum, D. R.</p> <p>2008-12-01</p> <p>We report the progress towards a genome-enabled instrument to monitor variations in microbial community in <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fields for long durations. Our long-term goal is to deploy an in situ microarray device embedded in a lab-on-a-chip device. The microarray detects both the 16S rRNA to identify prokaryotic species and cDNA (converted from mRNA) of selected functional genes to understand activities and dynamics of ocean microbial communities. Each automated, self-contained instrument contains a stack of disposable lab-on-a-chip devices. All measurements are performed on individual chips, starting with pumping seawater through on-chip filter to collect microbes, lysing cells to release nucleic acids, and then analyzing their genomic information. To aid the effort of building the first functional microarray, we participated in the TN-221 cruise funded by the National Science Foundation's Ocean Observatories Initiative to map the seafloor in areas of high scientific interest. During the cruise, multiple deep-sea water samples were collected. The microbes were filtered, frozen and shipped to our laboratory for molecular analysis. The DNA was isolated from these samples and a detailed metagenomic analysis is ongoing for samples of one <span class="hlt">site</span> (80 km offshore of Oregon coast, 380 km away from the Axial Seamount <span class="hlt">vent</span> field, and 5 meters above the 780- meter deep seafloor). From the isolated chromosomal DNA the 16S rRNA clone library was constructed and resultant clones were sequenced. Although the fluorescence microscopic analyses showed the density of biomass is relatively low, phylogenetic results suggested high diversity in these microbial communities. In addition, efforts were made to isolate mRNA directly from these deep-sea ocean samples. The information obtained from these analyses will be essential for development of oligonucleotide probes for the microarray device. First two authors contributed equally.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1987JGR....9211327P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1987JGR....9211327P"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Philpotts, J. A.; Aruscavage, P. J.; von Damm, K. L.</p> <p>1987-10-01</p> <p>Abundances of Li, Na, 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 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 13N (East Pacific Rise) fluids, albeit at higher levels. In contrast, fluids from 21N (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.</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://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 cone-forming processes is therefore likely. We propose that a combination of contact metamorphosis and associated <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> comparable to <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> complexes on Earth could have been the driving force of cone-formation in the study area based on the assumption of a high volatile content of the APF. The processes might then have proceeded as follows: Phase 1: The flooding of the study area by lava caused initial explosive reactions along the lava-APF-boundary forming clusters of pseudocraters. Pseudocraters are only visible towards the edges of the depression where the lava cover is thinnest. Towards the center the thick lava coverage prevented pseudocrater formation or quickly reburied forming cones. Phase 2: The heat of the cooling lava, which could be as thick as 500 m based on the diameters of flooded craters, causes contact metamorphosis and the mobilization of volatiles in the surrounding APF-sediments. Similar to <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> complexes on Earth, this may have caused hydrofracturing of the sediments and the formation of sediment pipes and dikes that transport the volatiles to the surface. Pre-existing fissures would have served as additional pathways. At the surface rapid decompression causes phreatic explosions and the formation of small cones. Phase 3: Close to the lava-body mobilization of volatiles (e.g. by dehydratation of hydrated minerals, mobilization of ground- or pore ice or even juvenile waters and other volatiles from the lava itself) was strongest. In combination with lower sediment thickness and shorter pathways to the surface, phreatic explosion were more violent and conduits may have been repeatedly active. The lower atmospheric pressure and lower gravity on Mars would have further enhanced the explosive activity. While the lower gravity leads to a faster ascent of the volatile-sediment-phase, thereby preventing early degassing, the lower atmospheric pressure causes stronger decompression and expansion of gases. With increasing distance and increasing APF-thickness the surface manifestation of the processes weakens and phreatic explosive activity decreases. The cracked domes and elongated ridges may then be the surface expression of sediment pipes and dikes that have cooled and degassed before reaching the surface. The flow structures surrounding many cones and ridges could be interpreted in this context as fluidized sediment as lava would not have been discharged from the <span class="hlt">vents</span>. This kind of sediment volcanism took place after the erosion of the APF and marks the end of the <span class="hlt">hydrothermal</span> activity. Phase 4: Erosion of the APF, enhanced by the cone-forming processes themselves, later exhumed deeper parts of the <span class="hlt">vents</span> and the brecciated sediment cores, leaving remnants of APF sediments in central pits and on top of cones, ridges and domes. References: [1] Plescia J. B. (1980) NASA Tech. Memo., 82385, 263-265. [2] Bridges J. C. et al. (2003) JGR, 180(E1), 5001, doi:10.1029/2001JE001820. [3] Fagents S. A. (2002) LPSC XXXIII, Abstract #1594. [4] Bruno B. C. (2004) JGR, 109, doi:1029/2004JE002273. [5] Theilig E. and Greeley R. (1979) J. Geophys. Res., 84, 7994-8010. [6] Page and Murray (2006) Icarus, 183, 46-54. [7] Skinner J. A. and Tanaka K. L. (2006) Icarus, 186, 41-59. [7] Watters T. R. et al. (2007) Sciencexpress, science. 1148112, 10.1126.</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://adsabs.harvard.edu/abs/2002AGUFM.V72A1303N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFM.V72A1303N"><span id="translatedtitle">Tidal bottom current modulation of chemical environment in the Suiyo <span class="hlt">hydrothermal</span> <span class="hlt">site</span> in the Izu-Ogasawara (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>Nakamura, K.</p> <p>2002-12-01</p> <p>Intense seafloor observatory studies were done at the Suiyo <span class="hlt">hydrothermal</span> <span class="hlt">site</span> in the summer of 2001 and 2002. Deployed instruments on the seafloor were CTD (Idronaut, Ocean Seven 316), Digiquartz precision pressure sensor and its recorder, 3-D acoustic current meters (NOBSKA, MAVS3), high temperature and redox recorders at the <span class="hlt">vents</span>, in-situ laser particle analyzer (Sequoia Scientific, LISST-Deep), methane sensor (CAPSUM METS) with its data logger, etc. The Suiyo Seamount <span class="hlt">hydrothermal</span> <span class="hlt">site</span> is located in the summit caldera of Izu-Ogasawara (Bonin) Arc (1380 m deep, 28.572 N, 140.643 E). The tide is mixed type dominant with semi-diurnal component. There is no tidal components in temperature and redox records neither at high temperature <span class="hlt">vents</span> (300 deg C) nor at low temperature <span class="hlt">vents</span> (less than 200 deg C). Whereas the temperature, redox, methane concentration in the seawater, particle characters measured just above the seafloor had strong semi-diurnal components. The methane concentration varies from several micro mol/litter to several tens of micro mol/litter associated with 200 mV redox change in the central part of the <span class="hlt">hydrothermal</span> <span class="hlt">site</span>. Semi-diurnal strong bottom current over 40 cm/sec appeared several hours after high tides introduced entrainment of ambient waters in the marginal part of <span class="hlt">hydrothermal</span> <span class="hlt">site</span> and accelerated mixing of <span class="hlt">vent</span> water with bottom water in the central part of the <span class="hlt">hydrothermal</span> <span class="hlt">site</span>. This research was funded by the "Archaean Park" Project (International research project on interaction between sub-<span class="hlt">vent</span> biosphere and geo environment funded by Special Coordination Fund of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. The R/V Natsushima cruise with the sub "Shinkai 2000" was a part of the Deep Sea Research project of the Japan Marine Science and Technology Center (JAMSTEC).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25665594','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25665594"><span id="translatedtitle">The complete mitogenome of the Atlantic <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> shrimp Rimicaris exoculata Williams & Rona 1986 (Crustacea: Decapoda: Alvinocarididae).</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yu, Yan-Qin; Liu, Xiao-Li; Li, Hua-Wei; Lu, Bo; Fan, Yu-Peng; Yang, Jin-Shu</p> <p>2016-09-01</p> <p>In this study we completely determined and analyzed the mitochondrial genome of the Mid-Atlantic Ridge <span class="hlt">hydrothermal-vent</span> shrimp Rimicaris exoculata (Crustacea: Decapoda: Alvinocarididae). The circular molecule is 15,902 bp in size with an AT content of 65.7%, composed of the same 37 mitochondrial genes as in all other known metazoan mitogenomes. Sequence composition of the R. exoculata mitogenome is exceptionally similar to that of its Indian-Ocean congener R. kairei, which suggests the fact that they might diverge at a quite recent age. The genome exhibits an ancestral pancrustacean arrangement of mitochondrial genes that presents only the translocation/inversion of trnL-UUR from the ancestral arthropod pattern. Determination of the R. exoculata mitogenome can help to resolve the consensus Decapoda tree of life. It also provides more genetic information available for phylogenetics as well as population genetics on this extensively studied species from <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. PMID:25665594</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://www.ncbi.nlm.nih.gov/pubmed/24317468','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24317468"><span id="translatedtitle">Two novel hepatocellular carcinoma cycle inhibitory cyclodepsipeptides from a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> crab-associated fungus Aspergillus clavatus C2WU.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jiang, Wei; Ye, Panpan; Chen, Chen-Tung Arthur; Wang, Kuiwu; Liu, Pengyuan; He, Shan; Wu, Xiaodan; Gan, Lishe; Ye, Ying; Wu, Bin</p> <p>2013-12-01</p> <p>Two novel cyclodepsipeptides containing an unusual anthranilic acid dimer and a D-phenyllactic acid residues, clavatustides A and B, were identified from cultured mycelia and broth of Aspergillus clavatus C2WU isolated from Xenograpsus testudinatus, which lives at extreme, toxic habitat around the sulphur-rich <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> in Taiwan Kueishantao. This is the first example of cyclopeptides containing an anthranilic acid dimer in natural products, and the first report of microbial secondary metabolites from the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> crab. Clavatustides A and B suppressed the proliferation of hepatocellular carcinoma (HCC) cell lines (HepG2, SMMC-7721 and Bel-7402) in a dose-dependent manner, and induced an accumulation of HepG2 cells in G1 phase and reduction of cells in S phase. PMID:24317468</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26312332','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26312332"><span id="translatedtitle">Two new species of Sericosura Fry & Hedgpeth, 1969 (Arthropoda: Pycnogonida: Ammotheidae) from a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> on the East Pacific Rise.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Jianjia; Lin, Rongcheng; Bamber, Roger N; Huang, Dingyong</p> <p>2013-01-01</p> <p>Between 17th October and 9th November 2009, the third leg of the Chinese DY115-21 cruise on board the R/V Dayangyihao, confirmed two new <span class="hlt">hydrothermal</span> fields near the equatorial East Pacific Rise. Five pycnogonid specimens were obtained by deep-sea TV-grab from one of the new <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> named 'Precious Stone Mountain' at 1.22°N 101.49°W. These specimens belonged to two new species of the obligately-<span class="hlt">vent</span>-associated pycnogonid genus Sericosura. Three female specimens represent the new species Sericosura gemmaenonsis with large body size. One male and one female were of the second new species, Sericosura dentatus; the male specimen has a mid-dorsal femoral cement-gland-tube, like that of Sericosura dissita, while the female specimen has more finely-denticulate spines on the oviger strigilis than any other species of the genus. PMID:26312332</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://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> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3017555','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3017555"><span id="translatedtitle">Pathways of Carbon and Energy Metabolism of the Epibiotic Community Associated with the Deep-Sea <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=pmc">PubMed Central</a></p> <p>Hgler, Michael; Petersen, Jillian M.; Dubilier, Nicole; Imhoff, Johannes F.; Sievert, Stefan M.</p> <p>2011-01-01</p> <p>Background The shrimp Rimicaris exoculata dominates the faunal biomass at many deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> at the Mid-Atlantic Ridge. In its enlarged gill chamber it harbors a specialized epibiotic bacterial community for which a nutritional role has been proposed. Methodology/Principal Findings We analyzed specimens from the Snake Pit <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field on the Mid-Atlantic Ridge by complementing a 16S rRNA gene survey with the analysis of genes involved in carbon, sulfur and hydrogen metabolism. In addition to Epsilon- and Gammaproteobacteria, the epibiotic community unexpectedly also consists of Deltaproteobacteria of a single phylotype, closely related to the genus Desulfocapsa. The association of these phylogenetic groups with the shrimp was confirmed by fluorescence in situ hybridization. Based on functional gene analyses, we hypothesize that the Gamma- and Epsilonproteobacteria are capable of autotrophic growth by oxidizing reduced sulfur compounds, and that the Deltaproteobacteria are also involved in sulfur metabolism. In addition, the detection of proteobacterial hydrogenases indicates the potential for hydrogen oxidation in these communities. Interestingly, the frequency of these phylotypes in 16S rRNA gene clone libraries from the mouthparts differ from that of the inner lining of the gill chamber, indicating potential functional compartmentalization. Conclusions Our data show the specific association of autotrophic bacteria with Rimicaris exoculata from the Snake Pit <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field, and suggest that autotrophic carbon fixation is contributing to the productivity of the epibiotic community with the reductive tricarboxylic acid cycle as one important carbon fixation pathway. This has not been considered in previous studies of carbon fixation and stable carbon isotope composition of the shrimp and its epibionts. Furthermore, the co-occurrence of sulfur-oxidizing and sulfur-reducing epibionts raises the possibility that both may be involved in the syntrophic exchange of sulfur compounds, which could increase the overall efficiency of this epibiotic community. PMID:21249205</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRC..121..836L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRC..121..836L"><span id="translatedtitle">Moored observation of abyssal flow and temperature near a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> on 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>Liao, Guanghong; Zhou, Beifeng; Liang, Chujin; Zhou, Huaiyang; Ding, Tao; Wang, Yuan; Dong, Changming</p> <p>2016-01-01</p> <p>Four moorings were deployed near "Dragon Flag," an active <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> in the valley of the Southwest Indian Ridge. The goal was to examine the variability of currents and temperature, which will guide the trajectory of spreading plumes. The mean current was cross-isobath, and the circulation was characterized by a submesoscale circulation. Observed currents also showed fluctuations with periods of 1-15 days. The inferred phase speed and wavelength for the wave with a period of 4.4 day are 10.4 km d-1 and 45.8km, respectively, which are consistent with the topographic Rossby wave theory. The persistent warming tendency with corresponding variation of salinity based on background θ-S properties may be caused by background circulation and divergence of the water column. The warming or cooling episodes were most likely as signatures of isopycnal surface depression or uplifting induced by the moving of mesoscale eddies. Well-resolved rotary spectra exhibited important nonlinear interactions between inertial and semidiurnal tide in the velocity and temperature records. Amplification of near-inertial currents in the near bottom is also exposed. These discoveries provided new evidence for the nonlinear interaction and trapped near-inertial waves by the ridge, which occurred in the deep ocean of the Southern Hemisphere. Such nonlinear interaction may represent a significant energy loss pathway for the internal waves, and part of the decay of such motion would likely result in increased mixing to maintain the abyssal stratification. Enhanced near-inertial motions can play a major role for the local advection of <span class="hlt">hydrothermal</span> plumes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007E%26PSL.257..132F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007E%26PSL.257..132F"><span id="translatedtitle">Physical controls on the salinity of mid-ocean ridge <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> fluids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fontaine, Fabrice J.; Wilcock, William S. D.; Butterfield, David A.</p> <p>2007-05-01</p> <p>Variations in the salinity of black smoker effluents (0.1- 8 wt.% NaCl) relative to seawater (3.2 wt.% NaCl) are attributed to phase separation and segregation of the resulting brines and vapors. However, models of phase separation predict brines with substantially higher salinities than observed at <span class="hlt">vents</span> and such brines are commonly observed in fluid inclusions from fossil <span class="hlt">hydrothermal</span> systems. It has been postulated that the range of observed salinities is controlled by the density of upwelling fluids. Here we present models of <span class="hlt">hydrothermal</span> circulation that predict the observed maximum salinity when an upper layer of high-permeability is included, and also reproduce black smoker temperatures when the upflow zone is surrounded by a low-permeability shell. Pressure gradients across the permeability boundary act as a density filter impeding the passage of high-salinity fluids, while the shell provides sufficient insulation to tap hot fluids to the surface. Our models fit the observations when the permeabilities of the upper layer differ from the permeability of the lower layer by factors of 10 and 100 in upflow and downflow regions, respectively, and when the permeability of the shell is one tenth that of the lower layer. The permeability structure we propose is consistent with observations in oceanic crust and inferences from ophiolites. While a previous study argues that black smoker temperatures are a consequence of the thermodynamic properties of seawater, our work suggests that very specific permeability configurations are required to match both the temperature and maximum salinity.</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://adsabs.harvard.edu/abs/1998DSRI...45.2189P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998DSRI...45.2189P"><span id="translatedtitle">Determination of nitrate in the blood of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworm Riftia pachyptila using a bacterial nitrate reduction assay</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pospesel, Mark A.; Hentschel, Ute; Felbeck, Horst</p> <p>1998-12-01</p> <p>The vestimentiferan tubeworm Riftia pachyptila derives most or all of its nutrition from intracellular chemosynthetic bacterial symbionts. Because purified preparations of symbionts respire nitrate, possibly nitrite, and oxygen, host transport of nitrate is a topic of interest. In the present study, we have developed a nitrate detection assay that utilizes a nitrite reductase-deficient Escherichia coli strain for the reduction of nitrate to nitrite, which is then determined spectrophotometrically. Nitrate and nitrite concentrations were measured in the blood and coelomic fluids of R. pachyptila collected from <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">sites</span> at 9°N and 13°N. The blood was shown to have nitrate concentrations up to one hundred times that of ambient sea water (40 μM). Blood nitrate levels reached concentrations of >1 mM, while nitrite was measured in the range of 400-700 μM. The concentrations of nitrate and nitrite in the coelomic fluids were 150-240 μM and <20 μM, respectively. The nitrate determination technique we present here is simple, applicable for laboratory and shipboard use on sea water or biological fluids, and works reliably within the 0.5 to 2000 μM range.</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.ncbi.nlm.nih.gov/pubmed/21673885','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21673885"><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=pubmed">PubMed</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=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/26373292','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26373292"><span id="translatedtitle">Hypnocyclicus thermotrophus gen. nov., sp. nov. isolated from a microbial mat in a <span class="hlt">hydrothermal</span> <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>Roalkvam, Irene; Bredy, Florian; Baumberger, Tamara; Pedersen, Rolf-B; Steen, Ida Helene</p> <p>2015-12-01</p> <p>The bacterial strain, IR-2T, was isolated from a microbial mat sampled near a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> in the Greenland Sea. Phylogenetic analysis, based on the 16S rRNA gene, showed that the closest relatives of IR-2T were Ilyobacter tartaricus, Ilyobacter insuetus, Propionigenium modestum and Fusobacterium varium (91 % 16S rRNA gene sequence similarity). The cells of the novel strain were Gram-stain-negative and pleomorphic; changing from long motile rods to non-motile ring structures during the growth cycle. Growth occurred at 20-55 °C (optimally at 48 °C), with 1-6 % (w/v) NaCl (optimally with 2 %), and at pH 5.3-8.0 (optimally at pH 6.0-8.0). The strain had obligate fermentative growth on various sugars and yeast extract. The DNA G+C content of strain IR-2T was 25.7 mol%. The cell sugars comprised mainly ribose, mannose and glucose, while the main polar lipids were glycolipids, phospholipids, phosphatidylglycerol and diphosphatidylglycerol. The fatty acid content of strain IR-2 was dominated by saturated and unsaturated iso-branched or anteiso-branched forms. Strain IR-2 represents a novel genus and species, for which the name Hypnocyclicus thermotrophus gen. nov., sp. nov. is proposed. The type strain is IR-2T ( = DSM 100055 = JCM 30901). PMID:26373292</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://adsabs.harvard.edu/abs/2013GGG....14.5244I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GGG....14.5244I"><span id="translatedtitle">Modeling fluid flow in sedimentary basins with sill intrusions: Implications for <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> and climate change</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Iyer, Karthik; Rpke, Lars; Galerne, Christophe Y.</p> <p>2013-12-01</p> <p>Large volumes of magma emplaced within sedimentary basins have been linked to multiple climate change events due to release of greenhouse gases such as CH4. Basin-scale estimates of thermogenic methane generation show that this process alone could generate enough greenhouse gases to trigger global incidents. However, the rates at which these gases are transported and released into the atmosphere are quantitatively unknown. We use a 2D, hybrid FEM/FVM model that solves for fully compressible fluid flow to quantify the thermogenic release and transport of methane and to evaluate flow patterns within these systems. Our results show that the methane generation potential in systems with fluid flow does not significantly differ from that estimated in diffusive systems. The values diverge when vigorous convection occurs with a maximum variation of about 50%. The fluid migration pattern around a cooling, impermeable sill alone generates <span class="hlt">hydrothermal</span> plumes without the need for other processes such as boiling and/or explosive degassing. These fluid pathways are rooted at the edges of the outer sills consistent with seismic imaging. Methane <span class="hlt">venting</span> at the surface occurs in three distinct stages and can last for hundreds of thousands of years. Our simulations suggest that although the quantity of methane potentially generated within the contact aureole can cause catastrophic climate change, the rate at which this methane is released into the atmosphere is too slow to trigger, by itself, some of the negative ?13C excursions observed in the fossil record over short time scales (<10,000 years).</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=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://adsabs.harvard.edu/abs/2012AGUFM.T51D2614Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.T51D2614Y"><span id="translatedtitle">Role of tectonic and volcanic activity in <span class="hlt">hydrothermal</span> systems at the southern Mariana Trough: detailed bathymetric characteristics of the <span class="hlt">hydrothermal</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>Yoshikawa, S.; Okino, K.; Asada, M.; Nogi, Y.; Mochizuki, N.; Nakamura, K.</p> <p>2012-12-01</p> <p>We present the detailed bathymetric characterization of field-scale geological features associated with <span class="hlt">hydrothermal</span> systems in the southern Mariana Trough near 12°57'N, 143°37'E, using near-bottom swath mapping data collected by the autonomous underwater vehicle (AUV) Urashima during cruise YK09-08 and dive observation data acquired by the submersible Shinkai6500 during cruise YK10-11. In the study area, two of the <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> are located on the active backarc spreading axis (the Snail and Yamanaka <span class="hlt">sites</span>), one is located at the eastern foot of the axial high (the Archean <span class="hlt">site</span>), and two are located on an off-axis knoll about 5 km from the spreading axis (the Pika and Urashima <span class="hlt">sites</span>). We examined 1) the nature of' tectonic and volcanic controls on the <span class="hlt">hydrothermal</span> systems, and 2) the relationship between geomorphological characteristics and <span class="hlt">hydrothermal</span> activity based on the survey results (Yoshikawa et al., 2012). The two on-axis <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> are possibly locally developed on a 4th order spreading segment, in association with diking events (on the basis of comparisons with previously studied cases on the East Pacific Rise). The three off-axis <span class="hlt">sites</span> (the Archean, Urashima, and Pika <span class="hlt">sites</span>) appear to represent locations of sustained <span class="hlt">hydrothermal</span> activity that has created relatively large-scale <span class="hlt">hydrothermal</span> features compared with those in the on-axis area. The formation of off-axis <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> is likely to be closely related to an off-axis magma upwelling system, as evidenced by the absence of fault systems and the undeformed morphology of the mound and knoll. The three off-axis <span class="hlt">hydrothermal</span> <span class="hlt">sites</span> are composed mainly of breccia assemblages that probably originated from <span class="hlt">hydrothermal</span> activity with black smoker <span class="hlt">venting</span>. These areas are characterized by numerous ridge lines (height, mainly 1-6 m), conical mounds (height: < 100 m, diameter: < 300 m), and bumpy seabed. Most of the ridge lines have formed as a result of collapse of the seafloor. The fragmental materials, steep slopes (generally 22°-37°), and perhaps <span class="hlt">hydrothermal</span> alteration of the seafloor are prerequisite for the collapse. In contrast, the on-axis <span class="hlt">sites</span> are characterized by the absence of ridge lines, and the presence of white smoker and shimmering observed on dome-shaped pillow mounds with smooth surfaces (height, 5-30 m; diameter, 250-320 m). Furthermore, in the off-axis area with no <span class="hlt">hydrothermal</span> activity, the mounds and the knoll have relatively smooth surfaces. Hence, the distribution of ridge lines, mound morphology, and bumpy seabed is likely to correlate with <span class="hlt">hydrothermal</span> activity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006DSRI...53.1101C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006DSRI...53.1101C"><span id="translatedtitle">Temporal variation in the antioxidant defence system and lipid peroxidation in the gills and mantle of <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>Company, Rui; Serafim, Angela; Cosson, Richard; Fiala-Mdioni, Aline; Dixon, David; Joo Bebianno, Maria</p> <p>2006-07-01</p> <p><span class="hlt">Hydrothermal</span> <span class="hlt">vent</span> mussels are exposed continually to toxic compounds, including high metal concentrations and other substances like dissolved sulphide, methane and natural radioactivity. Fluctuations in these parameters appear to be common because of the characteristic instability of the <span class="hlt">hydrothermal</span> environment. Temporal variation in the antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), total glutathione peroxidases (Total GPx), selenium dependent glutathione peroxidases (Se-GPx)), metallothioneins and lipid peroxidation (LPO) in the gills and mantle of the mussel Bathymodiolus azoricus from Menez-Gwen <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> <span class="hlt">site</span> was evaluated and related to the accumulated metal concentrations (Ag, Cu, Cd, Fe, Mn and Zn) in the tissues. Maximum antioxidant enzyme activities in the gills were detected in the beginning of summer, followed by a gradual decrease throughout the following months. One year after, the levels of antioxidant enzyme activities were similar to those reported one year before. LPO in this tissue exhibited a similar temporal variation trend. A different pattern of temporal variation in antioxidant enzyme activities was observed in the mantle, with a gradual increase from summer to the end of autumn (November). LPO in the mantle exhibited an almost reverse trend of temporal variation to that of antioxidant enzyme activities in this tissue. Antioxidant defences in the gills of B. azoricus were significantly enhanced with increasing concentrations of Ag, Cu and Mn, while negative relationships between antioxidant enzymes and Cd, Cu, Mn and Zn concentrations in the mantle were observed, suggesting different pathways of reactive oxygen species (ROS) production and that these tissues responded differently to the metal accumulation. However, temporal variation in biomarkers of defence and damage were in general similar to coastal bivalve species and can be associated with temporal variations of the physiological status due to reproduction. These variations might also be linked to the highly unstable nature of the <span class="hlt">hydrothermal</span> environment.</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/9408952','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/9408952"><span id="translatedtitle">Primary structure of the common polypeptide chain b from the multi-hemoglobin system of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tube worm Riftia pachyptila: an insight on the sulfide binding-<span class="hlt">site</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zal, F; Suzuki, T; Kawasaki, Y; Childress, J J; Lallier, F H; Toulmond, A</p> <p>1997-12-01</p> <p>The deep-sea tube worm Riftia pachyptila Jones possesses a multi-hemoglobin system with three different extracellular Hbs: two dissolved in the vascular blood, V1 (ca. 3,500 kDa) and V2 (ca. 400 kDa), and one in the coelomic fluid, C1 (ca. 400 kDa). V1 Hb consists of four heme-containing, globin chains (b-e) and four linker chains (L1-L4). V2 and C1 Hbs are exclusively built from globin chains, six for V2 (a-f) and five for C1 (a-e). The complete amino acid sequence of the isolated monomeric globin chain b, common to all Riftia Hbs, has been determined by automated Edman degradation sequencing of the peptides derived by digestion with trypsin, chymotrypsin, thermolysin, and CNBr. This polypeptide chain is composed of 144 amino acid residues, providing a M(r) of 16, 135.0 Da. Moreover, the primary sequence of chain b revealed 3 Cys residues at position 4, 75, and 134. Cys-4 and Cys-134 are located at positions where an intra-chain disulfide bridge is formed in all annelid, vestimentiferan, or pogonophoran chains, but Cys-75 is located at a unique position only found in three globin chains belonging to Lamellibrachia and Oligobrachia, a vestimentiferan and a pogonophoran. In both groups, Hbs can bind sulfide reversibly to fuel the chemosynthetic process of the symbiotic bacteria they harbor. Sulfide-binding experiments performed on purified Hb fractions (i.e., V1, V2, and C1 Hbs) suggest that free Cys residues on globin chains, and the numerous Cys found in linker chains, as determined previously by ESI-MS, may be the sulfide binding-<span class="hlt">sites</span>. Blocking the free Cys by N-ethylmaleimide, we confirmed that free cysteines were involved in sulfide-binding but did not account for the whole sulfide-binding capacity of V1 Hb. Furthermore, a phylogenetic tree was constructed from 18 globin-like chains of annelid, vestimentiferan, and pogonophoran extracellular Hbs to clarify the systematic position of tubeworms. Riftia chain b clearly belongs to the "strain A" family with 30 to 80% identity with the other sequences analyzed. Its position in the tree confirmed a close relationship between vestimentiferan, pogonophoran, and annelid Hbs. PMID:9408952</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.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://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 conditions during uprising and the similar solubility does not alter their abundance ratios.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V41C2806R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V41C2806R"><span id="translatedtitle">Insights into Spatial Sulfur Variation within the Modified Gill-Chamber of the Epibiont-Colonized <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Shrimp, Rimicaris exoculata</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rempfert, K. R.; Sievert, S. M.; Hansel, C. M.; Webb, S. M.; Thomas, F.</p> <p>2013-12-01</p> <p>Rimicaris exoculata dominates the megafaunal biomass at numerous Mid-Atlantic <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. Within the gill chamber of the shrimp exists a rich epibiotic community. These shrimp swarm around active black smoker chimneys at the Snake Pit <span class="hlt">vent</span> <span class="hlt">site</span> on the Mid-Atlantic Ridge, and have been hypothesized to utilize the mixing zone between ambient seawater and <span class="hlt">hydrothermal</span> fluid to supply these epibionts with a redox environment suitable for the promotion of chemoautotrophic growth. Investigation of the oxidation state, distribution, and concentration of sulfur of different compartments within the shrimp's gill chamber was conducted using synchrotron-based micro-X-ray fluorescence (micro-XRF) and micro-X-ray Absorption Near Edge Structure (micro-XANES) spectroscopy. Principle component analysis of point XANES spectra yielded four reference components indentified as elemental sulfur, sulfate, monosulfide (likely iron sulfide), and an organosulfur thiol compound. Energy specific micro-XRF mapping of these reference components in both the modified mouthparts and inner lining of the carapace enclosing the gill chamber displayed spatial heterogeneity in sulfur oxidation state and coordination. Sulfate, organosulfur thiol compounds, and phosphate tended to correlate with chitin structural features, while elemental sulfur was concentrated in areas where epibionts were observed. DNA extraction and sequencing from epibiont populations within each of the modified mouthparts and carapace was conducted to provide insight into the community structure at each of these distinct areas of the gill chamber. Here we demonstrate the complexity of sulfur speciation and mineralization in association with the host epibiont community composition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=124112','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=124112"><span id="translatedtitle">Isolation of Tellurite- and Selenite-Resistant Bacteria from <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> of the Juan de Fuca Ridge in the 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>Rathgeber, Christopher; Yurkova, Natalia; Stackebrandt, Erko; Beatty, J. Thomas; Yurkov, Vladimir</p> <p>2002-01-01</p> <p>Deep-ocean <span class="hlt">hydrothermal-vent</span> environments are rich in heavy metals and metalloids and present excellent <span class="hlt">sites</span> for the isolation of metal-resistant microorganisms. Both metalloid-oxide-resistant and metalloid-oxide-reducing bacteria were found. Tellurite- and selenite-reducing strains were isolated in high numbers from ocean water near <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, bacterial films, and sulfide-rich rocks. Growth of these isolates in media containing K2TeO3 or Na2SeO3 resulted in the accumulation of metallic tellurium or selenium. The MIC of K2TeO3 ranged from 1,500 to greater than 2,500 μg/ml, and the MIC of Na2SeO3 ranged from 6,000 to greater than 7,000 μg/ml for 10 strains. Phylogenetic analysis of 4 of these 10 strains revealed that they form a branch closely related to members of the genus Pseudoalteromonas, within the γ-3 subclass of the Proteobacteria. All 10 strains were found to be salt tolerant, pH tolerant, and thermotolerant. The metalloid resistance and morphological, physiological, and phylogenetic characteristics of newly isolated strains are described. PMID:12200320</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 Galpagos 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/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 μXRF). 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.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 (δ34S, Δ33S, ∆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 (δ18O) 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://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> <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/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://www.ncbi.nlm.nih.gov/pubmed/24670896','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24670896"><span id="translatedtitle">Defluviimonas indica sp. nov., a marine bacterium isolated from 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=pubmed">PubMed</a></p> <p>Jiang, Lijing; Xu, Hongxiu; Shao, Zongze; Long, Minnan</p> <p>2014-06-01</p> <p>A Gram-stain-negative, strictly aerobic, chemoheterotrophic marine bacterium, designated 20V17(T), was isolated from a deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> chimney collected from the South-west Indian Ridge. Cells of strain 20V17(T) were motile, short rods, 1.2-1.8 µm in length and 0.5-0.7 µm in width. Growth was observed at between 20 and 37 °C (optimum 25 °C-28 °C), pH 5.0 and 8.0 (optimum pH 7.0) and 0.5 and 8% (w/v) NaCl (optimum 1.5-2.0% NaCl). The major fatty acids were C(18 : 1)ω7c (74.4%), C(19 : 0) cyclo ω8c (11%), C(18 : 0) (5.1%) and C(18 : 0) 3-OH (2.8%), and the polar lipid profile comprised diphosphatidylglycerol, phosphatidylethanolamine, an unidentified glycolipid and four unidentified phospholipids. Ubiquinone 10 was the major quinone. The G+C content of genomic DNA was 66.3 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain 20V17(T) belonged to the genus Defluviimonas and shared 96.5 and 96.1% sequence similarity with Defluviimonas denitrificans D9-3(T) and Defluviimonas aestuarii BS14(T), respectively. On the basis of the taxonomic data obtained in this study, strain 20V17(T) represents a novel species of the genus Defluviimonas, for which the name Defluviimonas indica sp. nov. is proposed. The type strain is 20V17(T) (CGMCC 1.10859(T) = JCM 17871(T) = MCCC 1A01802(T)). PMID:24670896</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/26827710','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26827710"><span id="translatedtitle">Pontibacter amylolyticus sp. nov., isolated from a deep-sea sediment <span class="hlt">hydrothermal</span> <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>Wu, Yue-Hong; Zhou, Peng; Jian, Shu-Ling; Liu, Zhen-Sheng; Wang, Chun-Sheng; Oren, Aharon; Xu, Xue-Wei</p> <p>2016-04-01</p> <p>A Gram-stain-negative, short rod-shaped bacterium, designated 9-2T, was isolated from a sediment sample collected from a <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> field on the south-west Indian Ridge. It formed red colonies, produced carotenoid-like pigments and did not produce bacteriochlorophyll a. Strain 9-2T was positive for hydrolysis of DNA, gelatin and starch, but negative for hydrolysis of aesculin and Tween 60. The sole respiratory quinone was menaquinone-7 (MK-7). The main polar lipids consisted of phosphatidylethanolamine, one unidentified phospholipid and two unidentified polar lipids. The principal fatty acids (>5 %) were summed feature 4 (iso-C17 : 1 I and/or anteiso-C17 : 1 B), iso-C15 : 0 and iso-C17 : 0 3-OH. The genomic DNA G+C content was 49.2 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain 9-2T should be assigned to the genus Pontibacter. Levels of 16S rRNA gene sequence similarity between the new isolate and the type strains of Pontibacter species with validly published names were in the range 94.0-96.5 %. On the basis of phenotypic and genotypic data, strain 9-2T represents a novel species of the genus Pontibacter, for which the name Pontibacter amylolyticus sp. nov. is proposed. The type strain is 9-2T ( = CGMCC 1.12749T = JCM 19653T = MCCC 1K00278T). PMID:26827710</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://adsabs.harvard.edu/abs/1990DSRA...37..103T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990DSRA...37..103T"><span id="translatedtitle">Physical and biological factors affecting the behaviour and mortality of <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworms (vestimentiferans)</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; Garrett, John F.; Johnson, H. Paul</p> <p>1990-01-01</p> <p>Vestimentiferan tubeworms of two <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> on Juan de Fuca Ridge, northeast Pacific, were photographed with a time-lapse camera over periods of 1, 5 and 26 days and supplemented with video for 25 min. Current and turbidity measurements were also made. Mortality of the worms was heavy: 44% of the worms studied in the 26-day period were removed by falling sulphate/sulphide spires or died for other reasons. Predation effects are very common among collected specimens and implicate the activities of photographed rat-tail fish and polynoid polychaetes. Time-lag auto-correlations reveal a discernible semidiurnal and diurnal periodicity in the retraction/extension movements of the vestimentiferan population. However, no direct correlation exists with measures of surrounding currents or suspended particulates that have clear tidal components to their periodicity. Worms in each series were examined individually but no consistent endogenous rhythm could be identified. Worms are sensitive to touch and the approach of predators and exhibit rapid retraction responses. Although they do not appear to respond to the second-to-minute scale variations in sorrounding fluids, their short-term behaviour is highly variable. Over many days, the retractions/extension profile of each worm is quite constant and perhaps is the expression of a constant metanolic rate. The two species examined differ substantially, with less than half the Ridgeia piscesae being extended at any time compared to 3/4 of the R. phaeophiale population. Periods of retraction frequenlly last more than 30 min which man produce anaerobic conditions within the tube. Uptake of dissolved gases, and thus metabolic rate, is likely affected by both the specific retraction behaviour and branchial filament loss to predators.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.B51A0342S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.B51A0342S"><span id="translatedtitle">Free energy generation and transfers from Archaean <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> to the first metabolism</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Simoncini, E.; Kleidon, A.</p> <p>2010-12-01</p> <p>Dissipative structures are far from equilibrium systems which self - organize, maintaining a certain internal material order and require free energy in order to be conserved. From a geological point of view, thermal gradients were the most abundant sources of free energy on the early Earth. Here we demonstrate how chemical free energy can be produced by a geological process, serpentinization, associated to the electrochemical potential generation in off - axis <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>. The basis for chemical free energy generation is the thermal gradient between the crust and the Archean ocean, which is enhanced by the release of latent heat during serpentinization. Power can be extracted from this thermal gradient to generate motion. The convective motion of heated, chemically reduced fluid produces a redox front when in contact with the acidic Archaean ocean, generating electrical energy to be used in chemical reactions. Further, in the presence of porous inorganic, heterogeneous matrices acting as catalysts, self - sustained reaction chains raised. The free energy thus available could be used to allow the possibility for the establishment of first organic auto - catalytic chains. Molecular evolutionary steps from acetyl CoA to RNA-cleavage gave then rise to the first proto-metabolic processes. We use simple models to calculate the maximum rates of power transfer from the thermal gradient to electric energy to estimate the maximum possible rate of chemical free energy generation by this process. The model also takes into account the heterogeneity of the mineral matrix and its capability to catalyze reactions and to adsorb molecules selectively. In conclusion, non equilibrium thermodynamics in combination with maximum power assumptions help us to determine the fundamental limits of how much chemical free energy can be generated from a geothermal heat flux, providing conditions for the emergence of metabolism.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.B12A0774W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.B12A0774W"><span id="translatedtitle">Cross-Section of the Atlantis Massif --- Geologic Framework for the Lost City <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>Williams, E. A.; Karson, J. A.; Kelley, D. S.; Früh-Green, G. L.</p> <p>2003-12-01</p> <p>The Atlantis Massif is an oceanic core complex situated on 1.5-Ma-old crust at 30° N on the Mid-Atlantic Ridge. Its domed, corrugated upper surface is interpreted as a major detachment fault. The steep, mass-wasted south wall of the massif provides a window into the architecture of the footwall of this detachment fault and underlying rocks. Alvin and Argo II were used to collect outcrop-scale geological data in the context of fine-scale bathymetry from ABE surveys. Variably serpentinized peridotite and lesser gabbroic rock form the bulk of the massif. Outcrops below ˜1800 m.b.s.l. are generally massive, grading upward into a region cut by an array of shear zones, faults, and joints. The uppermost ˜50 m of basement rock show a pervasive anastomosing foliation dipping gently west and cropping out for about 3 km. Samples from this interval include mylonitic material wrapping around less deformed phacoids of basement rock. The mylonites are unconformably overlain by a thin (1-3 m) cap of breccia, grading upward into pelagic limestone. The breccia is massive to crudely bedded with both clast- and matrix-supported textures. It includes subangular clasts of basalt and serpentinite in a limestone matrix. Small normal faults offset all of these units and the unconformity. The Lost City <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Field sits on top of the breccia unit. We interpret the mylonites as a detachment fault responsible for exhumation of the upper mantle material that forms the core of the massif. The overlying sedimentary rocks represent debris shed onto the detachment fault surface when it defined the median valley wall. As the detachment fault surface moved off axis and flattened into its present orientation, the sedimentary material changed progressively from clastic to pelagic and became consolidated. This assemblage may cover the rest of the Atlantis Massif and occur on other oceanic core complexes.</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 μm 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> </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/2010AGUFMOS11D..04S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMOS11D..04S"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span> and Organic Falls in the Heart of the Coral Triangle: Chemosynthetic Communities Discovered via Telepresence in the Sangihe-Talaud Region, Northern Sulawesi, Indonesia</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.; Herrera, S.; Bors, E.; Munro, C.; Sibert, E.; Nganro, N.; Makarim, S.; Wirasantosa, S.; Tunnicliffe, V.; Baker, E. T.; Butterfield, D. A.; Holden, J. F.; Hammond, S. R.</p> <p>2010-12-01</p> <p>From June to August 2010, an international partnership of scientists and engineers from the United States, Canada, and Indonesia utilized the NOAA Ship Okeanos Explorer and HD video from the ROV Little Herc to explore virtually unknown deep seafloor in the heart of the Coral Triangle. The INDEX-SATAL 2010 expedition bathymetrically mapped more than 39,000sq km of the Sangihe-Talaud region, including several discrete volcanic cones on the western flank of the Sangihe Arc. Twenty <span class="hlt">sites</span> between 275m and 3650m were explored during 27 ROV dives, including the first (and only) known <span class="hlt">hydrothermally</span>-active <span class="hlt">site</span> (1850m) in the Indonesian region, Kawio Barat, a volcanically active seamount hosting chemosynthetic ecosystems. The dominant fauna inhabiting <span class="hlt">hydrothermally</span>-active areas were: 1) three shrimp morpho-species resembling Opaepele sp. and Chorocaris sp., intermingling on the sides of active smokers, amongst stalked barnacles, and scraping mineral surfaces; 2) large (10cm-long) polynoid scale worms (aff Branchinotogluma sp.) meandering through diffuse <span class="hlt">venting</span> and within barnacle assemblages; 3) discrete patches of tube-dwelling alvinellid polychaetes, and perhaps the most dominant, stalked Vulcanolepas barnacles, densely packed at the base of individual spires, as well as completely carpeting 3 to 4m-tall inactive chimneys on the summit crest of the seamount, particularly above the main group of active chimneys. Brachyuran and galatheid crabs were observed amongst stalked barnacles and in sulfide crevices. Vesicoymid-like clams (5 to 10cm long) were observed on the surface of volcanoclastic and pelagic sediment 50 to 125m down slope of the active <span class="hlt">venting</span>. Other potentially chemosynthetic habitats were observed at several <span class="hlt">sites</span>, including wooden logs and coconut shells. For example, the sedimented slopes of Seamount G (1926m) and flats of Memeridge (3600m) contained a notable lack of epibenthic fauna with the notable exception of frequent wood falls inhabited by a distinctive fauna: tubeworms, urchins, amphipods, galatheid crabs, serpulid worms and gastropod limpets, likely attracted by the organic enrichment. The fauna inhabiting Kawio Barat and these wood falls were markedly dissimilar. Recent molecular studies show that some of the fauna of <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> and organic falls have disparate physiological adaptations yet shared evolutionary histories, changing our view of evolution in the deep sea. These relationships as well as the potential isolation of Indonesian fauna to those inhabiting other chemosynthetic seamounts and <span class="hlt">sites</span> in the western Pacific will be discussed.</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 μM) 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 μM), 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://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; ΔpH, 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/2007AGUFM.B33A0847D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.B33A0847D"><span id="translatedtitle">Bacterial Diversity and Spatial Variability Found in a Mn-Fe Oxide Encrusted Microbial Mat From the 5000 Meter-Deep <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> 'Ula Nui, Hawaii</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.; Curtis, A. C.; Staudigel, H.; Tebo, B. M.</p> <p>2007-12-01</p> <p>'Ula Nui <span class="hlt">Vent</span> Field was discovered on the southern flank of Loihi Seamount during the 2006 FeMO Microbial Observatory expedition at over 5000 meters depth. The <span class="hlt">vent</span> field exhibited abundant low temperature (<2C above ambient) seeps which were covered with extensive mineral-encrusted microbial mat material. The microbial mats consisted of a 0.5-3 cm thick upper mat which was comprised of laminated layers of manganese oxides and iron oxides which overlayed a flocculent iron oxide mat that could attain depths of over 1 m deep. Bacterial communities from the top and bottom mats were analyzed using SSU rRNA terminal-restriction fragment polymorphisms (T-RFLP) coupled with traditional clone library analysis. T-RFLP chromatograms indicate dominance of the ?- Proteobacteria in both the top and lower mat. Cluster analysis of the T- RFLP fingerprints show a strong correlation between the bottom mat and iron oxide-encrusted microbial mats found in the <span class="hlt">hydrothermally</span> active Pele's Pit near the summit of Loihi Seamount. The top mat clusters with iron and manganese oxide encrusted microbial mats found at various <span class="hlt">sites</span> on Loihi Seamount not associated with measurable active <span class="hlt">hydrothermal</span> <span class="hlt">venting</span>. Clone library analysis show that the top mat was dominated by phylotypes related to the ?- ?- and the recently described ?- Proteobacteria, along with members of the Planctomycete Division. The dominance of ?- Proteobacteria and Planctomycete phylotypes implies that neutrophilic iron oxidation and anaerobic ammonia oxidation are active metabolisms in the top mat bacterial community. Anaerobic ammonia oxidation coupled with nitrite reduction may also be an integral metabolism in this community since some Planctomycete phylotypes from the top mat cluster within the anammox clade.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFMOS22A..08S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFMOS22A..08S"><span id="translatedtitle">Fluid flow rate, temperature and heat flux at Mohns Ridge <span class="hlt">vent</span> fields: evidence from isosampler measurements for phase separated <span class="hlt">hydrothermal</span> circulation along the arctic ridge system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schultz, A.; Pedersen, R. B.; Thorseth, I. H.; Taylor, P.; Flynn, M.</p> <p>2005-12-01</p> <p>An expedition to the Mohns Ridge in the Norwegian-Greenland sea was carried out in July-August 2005 as part of BIODEEP, lead by University of Bergen (UoB). UoB had previously detected water column methane along this very slow spreading ridge. Previous ROV observations along the ridge (71 deg 18'N, 5 deg 47'W, 605 mbsl) near Jan Mayen had uncovered a broad area of ferric hydroxide-rich bacterial/mineral assemblages, comprising large populations of gallionella bacteria. This area was revisted in 2005. Characteristic of sections of this area ("Gallionella Garden") are chimney-like structures standing ~15 cm tall, often topped by a sea lily (heliometra glacialis). The interior of the structures comprised quasi-concentric bands with vertically-oriented channels. The Oregon State University/Cardiff University Isosampler sensor determined that some of these assemblages support fluid flow through their interior. The outflow from the chimney structures was typically +0.5 deg C, against background temperatures of -0.3 deg C. Flow anomalies were also identified atop extensive bacterial mats. Gallionella Gardens is several km in extent with active, albeit extremely low temperature <span class="hlt">hydrothermal</span> flow. A field of active high temperature smoker chimney structures was located near Gallionella Garden at 540 mbsl. This field extends ~500 m along a scarp wall, with <span class="hlt">hydrothermal</span> mounds extending along faults running perpendicular to the scarp, each of which has multiple smoker <span class="hlt">vents</span> and areas of diffuse flow. There was evidence for phase separation, with a negatively buoyant fluid phase exiting some <span class="hlt">vent</span> orifices and descending along the <span class="hlt">vent</span> wall; and evidence for gas phase condensing after leaving some <span class="hlt">vent</span> orifices. Gas bubble emissions were not uncommon. Isosampler sensors were available that were configured for lower temperature measurements at Gallionella Garden. While capable of detecting variations in effluent at the 4 millidegree level, the temperature ceiling for the sensor tips available aboard ship was 260 deg C (800 deg C-capable isosampler sensors will be available for the 2006 field season). At this depth the phase separation point of seawater is 263 deg C. An isosampler sensor was deployed directly atop an apparently phase-separated white smoker chimney. The sensor indicated 260 deg C before terminating measurement. This was repeated at another <span class="hlt">vent</span> <span class="hlt">site</span>, indicating that the fluids were <span class="hlt">venting</span> at the point of phase separation. Indicated smoker plume flow rates were approximately 1/2 meter per second. A second field "Soria Moria" of high temperature <span class="hlt">vents</span> was discovered. This field is ~100 m on a side, and is densely populated by active white smoker chimneys, also with evidence for phase-separated flow. These <span class="hlt">vent</span> fields comprise the first ever arctic <span class="hlt">vent</span> plume sources ever visited by ROV and measured directly at the source of emission. A return to this area, and exploration and measurement further north is anticipated for 2006. The planned work includes comprehensive Isosampler and bioreactor fluid flow, sampling, geochemical and biogeochemical sampling and incubation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUSM.B13B..07L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUSM.B13B..07L"><span id="translatedtitle">Fossilization of Iron-Oxidizing Bacteria at <span class="hlt">Hydrothermal</span> <span class="hlt">Vents</span>: a Useful Biosignature 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>Leveille, R. J.; Lui, S.</p> <p>2009-05-01</p> <p>Iron oxidizing bacteria are ubiquitous in marine and terrestrial environments on Earth, where they often display distinctive cell morphologies and are commonly encrusted by minerals, especially bacteriogenic iron oxides and silica. Putative microfossils of iron oxidizing bacteria have been found in jaspers as old as 490Ma and microbial iron oxidation may be an ancient metabolic pathway. In order to investigate the usefulness of mineralized iron oxidizing bacteria as a biosignature, we have examined mineral samples collected from relict <span class="hlt">hydrothermal</span> systems along Explorer Ridge, NE Pacific Ocean. In addition, microaerophilic, neutrophilic iron oxidizing bacteria, isolated from Pacific <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, were grown in a Fe-enriched seawater medium at constant pH (6.5) and oxygen concentration (5 percent) in a controlled bioreactor system. Both natural samples and experimental products were examined with a combination of variable pressure scanning electron microscopy (SEM), field emission gun SEM, and in some cases by preparing samples with a focused ion beam (FIB) milling system. Natural seafloor samples display abundant filamentous forms often resembling, in both size and shape, the twisted stalks of Gallionella and the elongated filaments of Leptothrix. Generally, these filamentous features are 1-5 microns in diameter and up to several microns in length. Some samples consist entirely of low- density, porous masses of silica encrusted filamentous forms. Presumably, these masses were formed by a rapid precipitation by the influx of silica-rich fluids into a microbial mat dominated by bacteria with filamentous morphologies. The presence of rare, amorphous (unmineralized) filamentous matter rich in C and Fe suggests that these bacteria were iron oxidizers. There is no evidence that sulfur oxidizers were present. Filamentous features sectioned by FIB milling show internal material within semi-hollow tubular-like features. Silica encrustations also show pseudo-concentric growth bands. In the bioreactor cultures, constant conditions led to abundant microbial growth and formation of an iron oxyhydroxide precipitate, either in direct association with the cells or within the growth medium. This suggests that not all of the iron precipitation is biogenic in origin. Cells typically show a filamentous morphology reminiscent of the mineral-encrusted forms observed in the natural samples. Continuing work includes high-resolution TEM observations of cultured organisms, examination of 2-year long in situ seafloor incubation experiments, and bioreactor silicification experiments in order to better understand the roles of iron and silica in the fossilization process. Microaerophilic iron oxidation could have existed on the early Earth in environments containing small amounts of oxygen produced either by locally concentrated photosynthetic microorganisms (e.g., cyanobacteria) or abiotically, as proposed for the subsurface of the Fe-dominated Rio Tinto (Spain) basin system. By analogy, similar subsurface or near-surface microaerophilic environments could have existed on Mars in the past. The distinctive morphologies and mineralization patterns of iron oxidizing bacteria could be a useful biosignature to search for on Mars. Deposits and biogenic features similar to those described here could theoretically be identified on Mars with existing imaging and analytical technologies. Therefore, future missions to Mars should target ancient <span class="hlt">hydrothermal</span> systems, some of which have been putatively identified already.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AGUFM.V23A0592A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AGUFM.V23A0592A"><span id="translatedtitle">Visual Observations and Geologic Settings of the Newly-Discovered Black Smoker <span class="hlt">Vent</span> <span class="hlt">Sites</span> Across the Galapagos Ridge-Hotspot Intersection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Anderson, P.; Haymon, R.; MacDonald, K.; White, S.</p> <p>2006-12-01</p> <p>Nearly one-fifth of the global mid-ocean ridge is hotspot-affected, yet very little is known about how hotspots affect quantity and distribution of high-temperature <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> along the ridge. During the 2005-06 GalAPAGoS expedition, acoustic and plume sensor surveys were conducted across the Galapagos ridge- hotspot intersection, lon. 94.5ºW- lon. 89.5ºW, to map fine scale geologic features and locate <span class="hlt">hydrothermal</span> plumes emanating from the ridge crest. Where significant plumes were detected, the Medea fiber-optic camera sled was used successfully to find and image high-temperature <span class="hlt">vents</span> on the seafloor. With Medea we discovered and imaged the first active and recently extinct black smokers known along the entire Galapagos Spreading Center (GSC), and documented the geologic setting of these <span class="hlt">vents</span>. The Medea survey imaged numerous inactive <span class="hlt">vents</span> as well as 3 active high-temperature <span class="hlt">vent</span> fields along the ridge at 94º 04.5'W (Navidad <span class="hlt">Site</span>), 91º56.2'W (Iguanas <span class="hlt">Site</span>) and 91º54.3'W (Pinguinos <span class="hlt">Site</span>). Two recently extinct <span class="hlt">vent</span> fields also were identified at 91º23.4'-23.7'W and 91º13.8'W. All of the high-temperature <span class="hlt">vent</span> <span class="hlt">sites</span> that we identified along the GSC are found above relatively shallow AMC reflectors and are located in the middle 20% of ridge segments. Without exception the <span class="hlt">vent</span> <span class="hlt">sites</span> are located along fissures atop constructional axial volcanic ridges (AVR's) composed of relatively young pillow basalts. In some cases, the <span class="hlt">vents</span> were associated with collapses adjacent to the fissures. The fissures appear to be eruptive sources of the pillow lavas comprising the AVR's. Video images of the chimneys show mature, cylindrical structures, up to 14m high; little diffuse flow; few animals; and some worm casts and dead clam shells, suggesting prior habitation. We conclude that distribution of the <span class="hlt">vents</span> is controlled by magmatic processes, (i.e., by locations of shallow AMC magma reservoirs and eruptive fissures above dike intrusions), and that there is surprising similarity in the settings of the <span class="hlt">vents</span> and the apparent ages of the chimneys and lavas along ~400 n.m of the GSC spanning the Galapagos mantle plume.</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/2007AGUFM.P52A..02R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.P52A..02R"><span id="translatedtitle">The Arctic Gakkel <span class="hlt">Vents</span> (AGAVE) Expedition: Technology Development and the Search for Deep-Sea <span class="hlt">Hydrothermal</span> <span class="hlt">Vent</span> Fields Under the Arctic Ice Cap</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reves-Sohn, R. A.; Singh, H.; Humphris, S.; Shank, T.; Jakuba, M.; Kunz, C.; Murphy, C.; Willis, C.</p> <p>2007-12-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> fields on the Gakkel Ridge beneath the Arctic ice cap provide perhaps the best terrestrial analogue for volcanically-hosted chemosynthetic biological communities that may exist beneath the ice-covered ocean of Europa. In both cases the key enabling technologies are robotic (untethered) vehicles that can swim freely under the ice and the supporting hardware and software. The development of robotic technology for deep- sea research beneath ice-covered oceans thus has relevance to both polar oceanography and future astrobiological missions to Europa. These considerations motivated a technology development effort under the auspices of NASA's ASTEP program and NSF's Office of Polar Programs that culminated in the AGAVE expedition aboard the icebreaker Oden from July 1 - August 10, 2007. The scientific objective was to study <span class="hlt">hydrothermal</span> processes on the Gakkel Ridge, which is a key target for global studies of deep-sea <span class="hlt">vent</span> fields. We developed two new autonomous underwater vehicles (AUVs) for the project, and deployed them to search for <span class="hlt">vent</span> fields beneath the ice. We conducted eight AUV missions (four to completion) during the 40-day long expedition, which also included ship-based bathymetric surveys, CTD/rosette water column surveys, and wireline photographic and sampling surveys of remote sections of the Gakkel Ridge. The AUV missions, which lasted 16 hours on average and achieved operational depths of 4200 meters, returned sensor data that showed clear evidence of <span class="hlt">hydrothermal</span> <span class="hlt">venting</span>, but for a combination of technical reasons and time constraints, the AUVs did not ultimately return images of deep-sea <span class="hlt">vent</span> fields. Nevertheless we used our wireline system to obtain images and samples of extensive microbial mats that covered fresh volcanic surfaces on a newly discovered set of volcanoes. The microbes appear to be living in regions where reducing and slightly warm fluids are seeping through cracks in the fresh volcanic terrain. These discoveries shed new light on the nature of volcanic and <span class="hlt">hydrothermal</span> processes in the Arctic basin, and also demonstrate the importance of new technologies for advancing science beneath ice-covered oceans. Operationally, the AUV missions pushed the envelope of deep-sea technology. The recoveries were particularly difficult as it was necessary to have the vehicle find small pools of open water next to the ship, but in some cases the ice was in a state of regional compression such that no open water could be found or created. In these cases a well-calibrated, ship-based, short-baseline acoustic system was essential for successful vehicle recoveries. In all we were able to achieve a variety of operational and technological advances that provide stepping stones for future under-ice robotic missions, both on Earth and perhaps eventually on Europa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2660763','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2660763"><span id="translatedtitle">GeoChip-based analysis of metabolic diversity of microbial communities at the Juan de Fuca 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=pmc">PubMed Central</a></p> <p>Wang, Fengping; Zhou, Huaiyang; Meng, Jun; Peng, Xiaotong; Jiang, Lijing; Sun, Ping; Zhang, Chuanlun; Van Nostrand, Joy D.; Deng, Ye; He, Zhili; Wu, Liyou; Zhou, Jizhong; Xiao, Xiang</p> <p>2009-01-01</p> <p>Deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> are one of the most unique and fascinating ecosystems on Earth. Although phylogenetic diversity of <span class="hlt">vent</span> communities has been extensively examined, their physiological diversity is poorly understood. In this study, a GeoChip-based, high-throughput metagenomics technology revealed dramatic differences in microbial metabolic functions in a newly grown protochimney (inner section, Proto-I; outer section, Proto-O) and the outer section of a mature chimney (4143-1) at the Juan de Fuca Ridge. Very limited numbers of functional genes were detected in Proto-I (113 genes), whereas much higher numbers of genes were detected in Proto-O (504 genes) and 4143-1 (5,414 genes). Microbial functional genes/populations in Proto-O and Proto-I were substantially different (around 1% common genes), suggesting a rapid change in the microbial community composition during the growth of the chimney. Previously retrieved cbbL and cbbM genes involved in the Calvin Benson Bassham (CBB) cycle from deep-sea <span class="hlt">hydrothermal</span> <span class="hlt">vents</span> were predominant in Proto-O and 4143-1, whereas photosynthetic green-like cbbL genes were the major components in Proto-I. In addition, genes involved in methanogenesis, aerobic and anaerobic methane oxidation (e.g., ANME1 and ANME2), nitrification, denitrification, sulfate reduction, degradation of complex carbon substrates, and metal resistance were also detected. Clone libraries supported the GeoChip results but were less effective than the microarray in delineating microbial populations of low biomass. Overall, these results suggest that the <span class="hlt">hydrothermal</span> microbial communities are metabolically and physiologically highly diverse, and the communities appear to be undergoing rapid dynamic succession and adaptation in response to the steep temperature and chemical gradients across the chimney. PMID:19273854</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GGG....17.1000C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GGG....17.1000C"><span id="translatedtitle"><span class="hlt">Hydrothermal</span> <span class="hlt">venting</span> and mineralization in the crater of Kick'em Jenny submarine volcano, Grenada (Lesser Antilles)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carey, Steven; Olsen, Rene; Bell, Katherine L. C.; Ballard, Robert; Dondin, Frederic; Roman, Chris; Smart, Clara; Lilley, Marvin; Lupton, John; Seibel, Brad; Cornell, Winton; Moyer, Craig</p> <p>2016-03-01</p> <p>Kick'em Jenny is a frequently erupting, shallow submarine volcano located 7.5 km off the northern coast of Grenada in the Lesser Antilles subduction zone. Focused and diffuse <span class="hlt">hydrothermal</span> <span class="hlt">venting</span> is taking place mainly within a small (˜70 × 110 m) depression within the 300 m diameter crater of the volcano at depths of about 265 m. Much of the crater is blanketed with a layer of fine-grained tephra that has undergone <span class="hlt">hydrothermal</span> alteration. Clear fluids and gas are being discharged near the center of the depression from mound-like <span class="hlt">vents</span> at a maximum temperature of 180°C. The gas consists of 93-96% CO2 with trace amounts of methane and hydrogen. Gas flux measurements of individual bubble streams range from 10 to 100 kg of CO2 per day. Diffuse <span class="hlt">venting</span> with temperatures 5-35°C above ambient occurs throughout the depression and over large areas of the main crater. These zones are colonized by reddish-yellow bacteria with the production of Fe-oxyhydroxides as surface coatings, fragile spires up to several meters in height, and elongated mounds up to tens of centimeters thick. A high-resolution photomosaic of the inner crater depression shows fluid flow patterns descending the sides of the depression toward the crater floor. We suggest that the negatively buoyant fluid flow is the result of phase separation of <span class="hlt">hydrothermal</span> fluids at Kick'em Jenny generating a dense saline component that does not rise despite its elevated temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20030065875&hterms=yeast&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dyeast','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20030065875&hterms=yeast&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dyeast"><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://ntrs.nasa.gov/search.jsp?R=20080018899&hterms=Antibiotics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DAntibiotics','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080018899&hterms=Antibiotics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DAntibiotics"><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://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2175526','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2175526"><span id="translatedtitle">Tetraether membrane lipids of Candidatus “Aciduliprofundum boonei”, a cultivated obligate thermoacidophilic euryarchaeote 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>Baas, Marianne; Hopmans, Ellen C.; Reysenbach, Anna-Louise; Damsté, Jaap S. Sinninghe</p> <p>2007-01-01</p> <p>The lipid composition of Candidatus “Aciduliprofundum boonei”, the only cultivated representative of archaea falling in the DHVE2 phylogenetic cluster, a group of microorganisms ubiquitously occurring at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, was studied. The predominant core membrane lipids in this thermophilic euryarchaeote were found to be composed of glycerol dibiphytanyl glycerol tetraethers (GDGTs) containing 0–4 cyclopentyl moieties. In addition, GDGTs with an additional covalent bond between the isoprenoid hydrocarbon chains, so-called H-shaped GDGTs, were present. The latter core lipids have been rarely reported previously. Intact polar lipid analysis revealed that they predominantly consist of GDGTs with a phospho-glycerol headgroup. PMID:17901915</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17901915','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17901915"><span id="translatedtitle">Tetraether membrane lipids of Candidatus "Aciduliprofundum boonei", a cultivated obligate thermoacidophilic euryarchaeote 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>Schouten, Stefan; Baas, Marianne; Hopmans, Ellen C; Reysenbach, Anna-Louise; Damsté, Jaap S Sinninghe</p> <p>2008-01-01</p> <p>The lipid composition of Candidatus "Aciduliprofundum boonei", the only cultivated representative of archaea falling in the DHVE2 phylogenetic cluster, a group of microorganisms ubiquitously occurring at <span class="hlt">hydrothermal</span> <span class="hlt">vents</span>, was studied. The predominant core membrane lipids in this thermophilic euryarchaeote were found to be composed of glycerol dibiphytanyl glycerol tetraethers (GDGTs) containing 0-4 cyclopentyl moieties. In addition, GDGTs with an additional covalent bond between the isoprenoid hydrocarbon chains, so-called H-shaped GDGTs, were present. The latter core lipids have been rarely reported previously. Intact polar lipid analysis revealed that they predominantly consist of GDGTs with a phospho-glycerol headgroup. PMID:17901915</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1994DSRI...41.1447T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1994DSRI...41.1447T"><span id="translatedtitle">Unusual carbon dioxide-combining properties of body fluids in the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworm Riftia pachyptila</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Toulmond, André; Lallier, François H.; de Frescheville, Jacques; Childress, James J.; Lee, Raymond; Sanders, Nancy K.; Desbruyères, Daniel</p> <p>1994-10-01</p> <p>Total CO 2 (ΣCO 2) up to 50 mmol l -1, corresponding to internal CO 2 partial pressures (P CO 2) up to 6 kPa (1 kPa ≈ 7.5 mm Hg or Torr), have been measured in the body fluids of the <span class="hlt">hydrothermal</span> <span class="hlt">vent</span> tubeworm Riftia pachyptila (Jones) sampled at 13°N on the East Pacific Rise. At physiological pH values, such high ΣCO 2 and P CO 2 are quite unusual in water-breathing animals. In Riftia, both blood and coelomic fluid contain extracellular haemoglobins at fairly high concentrations, but their titration by a strong acid as well as CO 2 equilibration experiments on dialysed and ultra-filtered fluids showed that the presence of these proteins account for only one-tenth to one-third of the observed ΣCO 2. Gel filtration analysis of the fluids revealed that the protein-free fractions retained most of the CO 2: about 64% in blood and 80% in coelomic fluid. This corresponds to a base excess of unknowm nature and origin at a concentration up to 30 meq l -1. The nutritional needs of the mouthless and gutless Riftia are totally derived from the metabolic activity of sulphide-oxidizing, chemolithoautotrophic bacterial symbionts able to fix inorganic carbon into organic molecules. In an external environment in which P CO 2 varies widely due to the turbulent mixing of the hot, sulphide- and CO 2-rich vebt water with the cold, CO 2-poor deep sea water, we propose that the base excess has three main functions: first, to retain CO 2 in the body fluids when the external P CO 2 is low; second, to act as a buffer when external P CO 2 is high; third, to allow the large coelomic compartment to act as a CO 2 store, thus permitting the symbiotic bacteria to fix carbon continuously even when the external supply of carbon dioxide fluctuates.</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> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5108427','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5108427"><span id="translatedtitle">Geochemistry of <span class="hlt">hydrothermal</span> fluids from Axial Seamount <span class="hlt">Hydrothermal</span> Emissions Study <span class="hlt">vent</span> field, Juan de Fuca Ridge: Subseafloor boiling and subsequent fluid-rock interaction</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Butterfield, D.A.; McDuff, R.E.; Lilley, M.D. ); Massoth, G.J. ); Lupton, J.E. )</p> <p>1990-08-10</p> <p><span class="hlt">Hydrothermal</span> fluids collected from the ASHES <span class="hlt">vent</span> field in 1986, 1987, and 1988 exhibit a very wide range of chemical composition over a small area ({approximately} 60 m in diameter). Compositions range from a 300C, gas-enriched (285 mmol/kg CO{sub 2}), low-chlorinity ({approximately} 33% of seawater) fluid to a 328C, relatively gas-depleted (50 mmol/kg CO{sub 2}), high-chlorinity ({approximately} 116% of seawater) fluid. The entire range of measured compositions at ASHES is best explained by a single <span class="hlt">hydrothermal</span> fluid undergoing phase separation while rising through the ocean crust, followed by partial segregation of the vapor and brine phases. Other mechanisms proposed to produce chlorinity variations in <span class="hlt">hydrothermal</span> fluids (precipitation/dissolution of a chloride-bearing mineral or crustal hydration) cannot produce the covariation of chlorinity and gas content observed at ASHES. There is good argument of the measured fluid compositions generated by a simple model of phase separation, in which gases are partitioned according to Henry's law and all salt remains in the liquid phase. Significant enrichments in silica, lithium and boron in the low-chlorinity fluids over levels predicted by the model are attributed to fluid-rock interaction in the upflow zone. Depletions in iron and calcium suggest that these elements have been removed by iron-sulfide and anhydrite precipitation at some time in the history of the low-chlorinity fluids. The distribution of low- and high-chlorinity <span class="hlt">venting</span> is consistent with mechanisms of phase segregation based on differential buoyancy or relative permeability. The relatively shallow depth of the seafloor (1,540 m) and the observed chemistry of ASHES fluids are consistent with phase separation in the sub-critical or near-critical region.</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/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>