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1

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

E-print Network

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

Keller, Randall A

2

Discovery of new hydrothermal vent sites in Bransfield Strait, Antarctica  

NASA Astrophysics Data System (ADS)

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 (42-49C) 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 250C. 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.

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

2001-12-01

3

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

NASA Astrophysics Data System (ADS)

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 3C and 33.5C 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 200C and 301C 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.

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

2012-04-01

4

Bacteria at Hydrothermal Vents  

NSDL National Science Digital Library

This website provides information on thermophiles living in deep-sea vents, including their importance in biotechnology and extraterrestrial life research. The site also contains images of thermophiles at varying scales and a link to the "Hot Topics" main page including numerous links to further information on hydrothermal vents and research conducted in deep-sea environments.

Expeditions to the Sea Floor Dive and Discover

5

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

E-print Network

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

Reysenbach, Anna-Louise

6

Life at Hydrothermal Vents  

NSDL National Science Digital Library

The first Web site is a NOVA Online Adventure from PBS (1). Into the Abyss decribes the "pitch darkness, poison gas, heavy metals, extreme acidity, and enormous pressure" found at hydrothermal vents, and offers a look at bizarre and fascinating creatures found in this environment. The next Web site from Exploring Earth, an online earth sciences text book, contains video clips taken during research expeditions along the Juan de Fuca Ridge (2). Ocean AdVENTure, a ThinkQuest Web site, offers a comprehensive and well-designed introduction to hydothermal vents from research tools to fauna to unsolved mysteries and more (3). Visitors can choose their own scientific adVENTure to explore hydrothermal vents in this interactive feature from the University of Washington School of Oceonagraphy Exploraquarium (4). Dive and Discover is "an interactive distance learning Web site designed to immerse you in the excitement of discovery and exploration of the deep seafloor." This Web site (5) extends a virtual invitation to join scientists aboard research cruises to the depth of the Pacific and Indian Oceans, providing daily logs, video, and other features for each expedition. The next Web site from the University of California-Berkeley offer a closer look at the "strange tube-dwelling worm" phylum found only near hydrothermal vents (6). Creature Features, provided by the University of Delaware Graduate College of Marine Science, contains descriptions and video clips of tubeworms, vent crabs, Pompeii crabs, and ancient bacteria found at deep sea vents (7). The last Web site (8) is a transcript of a June 1997 PBS NewsHour interview with science writer William Broad. Broad discusses his book The Universe Below: Discovering the Secrets of the Deep Sea, and relates the exciting opportunities for scientific exploration of the sea floor made possible by the end of the Cold War.

Sohmer, Rachel.

2002-01-01

7

Stabilization of dissolved trace metals at hydrothermal vent sites: Impact on their marine biogeochemical cycles  

NASA Astrophysics Data System (ADS)

Hydrothermal vents have long been neglected as a significant source of several bioactive trace metals as it was assumed that elements such as Fe, Mn, and Cu etc., precipitate in extensor forming poly-metallic sulfide and oxy-hydroxy sediments in the relative vicinity of the emanation site. However, recently this paradigm has been reviewed since the stabilization of dissolved Fe and Cu from hydrothermal vents was observed [1, 2] and increased concentrations of trace metals can be traced from their hydrothermal source thousands of kilometres through the ocean basins [3]. Furthermore several independent modelling attempts have shown that not only a stabilization of dissolved hydrothermal Fe and Cu is possible [4] but also that hydrothermalism must be a significant source of Fe to be able to balance the Fe-biogeochemical cycle [5]. Here we present new data that gives further evidence of the presence of copper stabilising organic and inorganic compounds in samples characterized by hydrothermal input. We can show that there are systematic differences in copper-complexing ligands at different vent sites such as 5S on the Mid Atlantic Ridge, Brother Volcano on the Kermadec Arc, and some shallow hydrothermal CO2 seeps in the Bay of Plenty, New Zealand and the Mediterranean Sea. Quantitative and qualitative voltammetric data convincingly indicates that inorganic sulphur and organic thiols form the majority of the strong copper-complexing ligand pool in many of these hydrothermal samples. On average, the high temperature vents had a significantly higher copper binding capacity than the diffuse vents due to higher inorganic sulphur species concentrations. References: [1] Sander, S. G., et al. 2007. Organic complexation of copper in deep-sea hydrothermal vent systems. Environmental Chemistry 4: 81-89 [2] Bennett, S. A., et al. 2008. The distribution and stabilisation of dissolved Fe in deep-sea hydrothermal plumes. Earth and Planetary Science Letters 270: 157-167. [3] Wu J. et al. 2011. Dissolved iron anomaly in the deep tropical-subtropical Pacific: Evidence for long-range transport of hydrothermal iron. Geochimica et Cosmochimica Acta 75: 460-468. [4] Sander, S. G., and A. Koschinsky. 2011. Metal flux from hydrothermal vents increased by organic complexation. Nature Geoscience 4: 145-150 DOI:10.1038/ngeo1088. [5] Tagliabue, A. et al. 2010. Hydrothermal contribution to the oceanic dissolved iron inventory. Nature Geoscience 3: 252-256 DOI: 10.1038/NGEO818

Sander, Sylvia G.; Powell, Zach D.; Koschinsky, Andrea; Kuzmanovski, Stefan; Kleint, Charlotte

2014-05-01

8

Dive and Discover's Deeper Discovery: Hydrothermal Vents  

NSDL National Science Digital Library

Dive and Discover is an interactive distance learning web site designed to immerse you in the excitement of discovery and exploration of the deep seafloor. On this particular website, Dive and Discover takes you on a deeper discovery of hydrothermal vents. This site features an introduction to hydrothermal vent systems, including vent basics, vents around the world, chemistry, boiling points, interactive diagrams, videos, a quiz, and links to selected Dive and Discover hydrothermal vent-related seafloor expeditions. This web page also provides links to other Deeper Discovery topics, Dive and Discover seafloor expeditions, a teacher's page, and further Dive and Discover information.

9

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

NASA Astrophysics Data System (ADS)

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 13C and 15N 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 13C, 15N and 34S values than sessile genera due to mobile organisms' ability to forage for photosynthetically derived detritus.

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

2008-12-01

10

Temperature variations at diffuse and focused flow hydrothermal vent sites along the northern East Pacific Rise  

Microsoft Academic Search

In the decade following documented volcanic activity on the East Pacific Rise near 950?N, we monitored hydrothermal vent fluid temperature variations in conjunction with approximately yearly vent fluid sampling to better understand the processes and physical conditions that govern the evolution of seafloor hydrothermal systems. The temperature of both diffuse flow (low-temperature) and focused flow (high-temperature) vent fluids decreased significantly

Daniel S. Scheirer; Timothy M. Shank; Daniel J. Fornari

2006-01-01

11

Submarine hydrothermal vents and associated gradient environments as sites for the origin and evolution of life  

Microsoft Academic Search

Submarine hydrothermal vents are the only comtemporary geological environment which may be called truly primeval; they continue to be a major source of gases and dissolved elements to the modern ocean as they were to the Archean ocean. Then, as now, they encompassed a multiplicity of physical and chemical gradients as a direct result of interactions between extensive hydrothermal activity

John A. Baross; Sarah E. Hoffman

1985-01-01

12

Geologic setting of the Snake Pit hydrothermal site: An active vent field on the Mid-Atlantic Ridge  

NASA Astrophysics Data System (ADS)

The Snake Pit Hydrothermal Site lies on the axis of the Mid-Atlantic Ridge at 2322' N latitude, about 30 km south of the Kane Transform Intersection. Active black smoker vents and a surrounding field of hydrothermal sediment occur at the crest of a laterally extensive neovolcanic ridge. It is one of the first active hydrothermal vent fields to be found on a slow-spreading ridge axis and despite significant differences in its geologic setting from those of the East Pacific Rise, has many similarities to its fast-spreading counterparts. Although preliminary reports have documented many interesting aspects of these vents and their surroundings, new data collected from the manned submersible ALVIN and the deep-towed ANGUS camera system define the regional tectonic setting as well as the local geologic environment of this fascinating area. The Snake Pit vents are located on a local peak of a volcanic constructional ridge at a depth of 3450 m, 700 800 m deeper than vents known from the East Pacific Rise, Galapagos, or Juan de Fuca spreading centers. The vent field is at least 600 m long and up to 200 m wide and is covered by a thick blanket of greenish to yellow-orange hydrothermal sediment. Both active and extinct vents are perched along the crests of steep-sided sulfide mounds that reach heights of over 40 m. High-temperature (350 C) fluids are vented from black smoker chimneys and low-temperature (226 C) fluids seep from sulphide domes and subordinate anhydrite constructions. Water temperatures, flow rates, fluid chemistries, and mineralization are strikingly similar to vents of faster spreading ridge crests; however, a somewhat distinct fauna inhabit the area.

Karson, Jeffrey A.; Brown, Jennifer R.

1988-03-01

13

Microbial Utilization of Naturally Occurring Hydrocarbons at the Guaymas Basin Hydrothermal Vent Site  

PubMed Central

The Guaymas Basin (Gulf of California; depth, 2,000 m) is a site of hydrothermal activity in which petroliferous material 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 [1-14C]hexadecane and [1(4,5,8)-14C]naphthalene to 14CO2 was observed at 4C and 25C, and some was observed at 55C, but none was observed at 80C. 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 5C). 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. PMID:16348045

Bazylinski, Dennis A.; Wirsen, Carl O.; Jannasch, Holger W.

1989-01-01

14

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

SciTech Connect

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.

Bazylinski, D.A.; Wirsen, C.O.; Jannasch, H.W. (Woods Hole Oceanographic Institution, MA (USA))

1989-11-01

15

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

16

ADAPTATIONS TO SULFIDE BY HYDROTHERMAL VENT ANIMALS: SITES AND MECHANISMS OF DETOXifiCATION AND METABOLISM  

Microsoft Academic Search

The detoxification and metabolism of sulfide were studied in three symbiont containing invertebrates from the deep-sea hydrothermal vents: the tube worm, R@ftia pachyptila; the clam, Ca!yptogena nwgn@fica; and the mussel, Bathymodiolus ther mophilus. Sulfide oxidizing activities, due to specific sulfide oxidase enzymes, were found in all tissues, with the greatestactivities occurringin the symbiont-contaiing tissues:the trophosome ofthe tube worm and the

M. A. POWELLAND; G. N. SOMERO

17

The Discovery of Marine Hydrothermal Vents  

NSDL National Science Digital Library

As part of OceanLink, a website dedicated to ocean education, this site gives an overview of the discovery, geology and ecology of marine hydrothermal vents. The site also provides a menu of links to access other OceanLink pages for further ocean-related information.

OceanLink

18

Iron (II) distribution and oxidation kinetics in hydrothermal plumes at the Kairei and Edmond vent sites, Indian Ocean  

Microsoft Academic Search

Deep-sea hydrothermal activity cycles the entire volume of the global ocean through deep-sea hydrothermal plumes at least every 48103 a, a rapid timescale that is comparable to global deep-ocean mixing. An important process within hydrothermal plumes is the oxidation of dissolved iron discharged with vent fluids, leading to the co-precipitation of many other vent-sourced metals, thus, modifying gross hydrothermal fluxes

P. J. Statham; C. R. German; D. P. Connelly

2005-01-01

19

Explore Life at a Hydrothermal Vent  

NSDL National Science Digital Library

This site features Flash movies about the physical and biological characteristics of submarine vents. Some of the animations are simulated and some are real footage from remotely controlled instruments. Topics include the chemistry of water emitted by hydrothermal vents, as well as worms, octopuses, and other biota that inhabit these extreme environments. The video clips were taken during research expeditions along the Juan de Fuca Ridge, off the coast of Washington and Oregon.

Classzone - Exploring Earth

20

Vision in hydrothermal vent shrimp.  

PubMed Central

Bresiliid shrimp from hydrothermal vents on the Mid-Atlantic Ridge have non-imaging eyes adapted for photodetection in light environments of very low intensity. Comparison of retinal structures between both vent shrimp and surface-dwelling shrimp with imaging eyes, and between juvenile and adult vent shrimp, suggests that vent shrimp have evolved from ancestors that lived in a light environment with bright cyclic lighting. Whether the vent shrimp live in swarms and have large dorsal eyes or live in sparse groupings and have large anterior eyes, the basic retinal adaptations are the same across species. Retinal adaptations in adult vent shrimp include the loss of dioptrics, enlargement of both the rhabdomeral segment of the photoreceptors and the light-sensitive rhabdomere therein, attenuation of the arhabdomeral segment of the photoreceptors, reduction of black screening pigment, development of a white diffusing layer behind the photoreceptors, and the loss of rhabdom turnover. PMID:11079388

Chamberlain, S C

2000-01-01

21

Hydrothermal Vents: Thar She Blows!  

NSDL National Science Digital Library

In this lesson students will discover how the proximity of hot magma to cold ocean water creates new rocky structures around hydrothermal vents. During this activity, students will demonstrate an understanding of how the processes that result in the formation of hydrothermal vents create new ocean floor and how the transfer of energy effects solids and liquids. This hands-on activity uses online data resources and includes: focus questions, learning objectives, teaching time, audio/visual materials needed, background information, learning procedures, evaluations, extensions, as well as resources and student handouts.

22

Mystery of the Megaplume: Hydrothermal Vent Chemistry  

NSDL National Science Digital Library

In this lesson, students will investigate hydrothermal vents to see how the chemistry of the water they emit provides clues to the location of the vents. They should be able to describe hydrothermal vents and characterize vent plumes in terms of physical and chemical properties; describe data gathering operations in which a towed instrument package ("tow-yo") measures conductivity, temperature, and depth; and interpret temperature anomaly data to recognize a plume emanating from a hydrothermal vent.

23

Hydrothermal sediments as a potential record of seawater Nd isotope compositions: The Rainbow vent site (3614?N, Mid-Atlantic Ridge)  

Microsoft Academic Search

Geochemical compositions and Sr and Nd isotopes were measured in two cores collected ?2 and 5 km from the Rainbow hydrothermal vent site on the Mid-Atlantic Ridge. Overall, the cores record enrichments in Fe and other metals from hydrothermal fallout, but sequential dissolution of the sediments allows discrimination between a leach phase (easily leachable) and a residue phase (refractory). The

Valrie Chavagnac; Martin R. Palmer; J. Andrew Milton; Darryl R. H. Green; Christopher R. German

2006-01-01

24

Iron (II) distribution and oxidation kinetics in hydrothermal plumes at the Kairei and Edmond vent sites, Indian Ocean  

Microsoft Academic Search

Deep-sea hydrothermal activity cycles the entire volume of the global ocean through deep-sea hydrothermal plumes at least every 4 8 103 a, a rapid timescale that is comparable to global deep-ocean mixing. An important process within hydrothermal plumes is the oxidation of dissolved iron discharged with vent fluids, leading to the co-precipitation of many other vent-sourced metals, thus, modifying

P. J. Statham; C. R. German; D. P. Connelly

2005-01-01

25

AUTOMATED PLANNING FOR HYDROTHERMAL VENT PROSPECTING USING  

E-print Network

AUTOMATED PLANNING FOR HYDROTHERMAL VENT PROSPECTING USING AUVS by ZEYN A SAIGOL A thesis submitted of searching the ocean floor for hydrothermal vents, using autonomous underwater vehicles (AUVs). This is a hard problem because the AUV's sensors cannot directly measure the range or bearing to vents

Yao, Xin

26

Chemosynthetic microbial activity at Mid-Atlantic Ridge hydrothermal vent sites  

Microsoft Academic Search

Chemosynthetic production of microbial biomass, determined by 14CO2 fixation and enzymatic (RuBisCo) activity, at the Mid-Atlantic Ridge (MAR) 23 and 26N vent sites was found in various niches: warm water emissions, loosely rock-attached flocculent material, dense morphologically diverse bacterial mats covering the surfaces of polymetal sulfide deposits, and filamentous microbes on the carapaces of shrimp (Rimicaris exoculata). The bacterial mats

Carl O. Wirsen; Holger W. Jannasch; Stephen J. Molyneaux

1993-01-01

27

Chemosynthetic microbial activity at Mid-Atlantic Ridge hydrothermal vent sites  

NASA Astrophysics Data System (ADS)

Chemosynthetic production of microbial biomass, determined by 14CO2 fixation and enzymatic (RuBisCo) activity, at the Mid-Atlantic Ridge (MAR) 23 and 26N vent sites was found in various niches: warm water emissions, loosely rock-attached flocculent material, dense morphologically diverse bacterial mats covering the surfaces of polymetal sulfide deposits, and filamentous microbes on the carapaces of shrimp (Rimicaris exoculata). The bacterial mats on polymetal sulfide surfaces contained unicellular and filamentous bacteria which appeared to use as their chemolithotrophic electron or energy source either dissolved reduced minerals from vent emissions, mainly sulfur compounds, or solid metal sulfide deposits, mainly pyrite. Moderately thermophilic Chemosynthetic activity was observed in carbon dioxide fixation experiments and in enrichments, but no thermophilic aerobic sulfur oxidizers could be isolated. Both obligate and facultative chemoautotrophs growing at mesophilic temperatures were isolated from all chemosynthetically active surface scrapings. The obligate autotrophs could oxidize sterilized MAR natural sulfide deposits as well as technical pyrite at near neutral pH, in addition to dissolved reduced sulfur compounds. While the grazing by shrimp on the surface mats of MAR metal sulfide deposits was observed and deemed important, the animals' primary occurrence in dense swarms near vent emissions suggests that they were feeding at these sites, where conditions for Chemosynthetic growth of their filamentous microbial epiflora were optimal. The data show that the transformation of geothermal energy at the massive polymetal sulfide deposits of the MAR is based on the lithoautotrophic oxidation of soluble sulfides and pyrites into microbial biomass.

Wirsen, Carl O.; Jannasch, Holger W.; Molyneaux, Stephen J.

1993-06-01

28

Hydrothermal vent complexes associated with sill intrusionsin sedimentarybasins  

E-print Network

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

Podladchikov, Yuri

29

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)

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.

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

2012-12-01

30

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

ERIC Educational Resources Information Center

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

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

31

Hydrothermal Vent Animals: Distribution and Biology  

Microsoft Academic Search

Hydrothermal vent communities characterized by large clams, mussels, and vestimentiferan worms thrive on chemosynthetic microbial production. There are similarities in the animal distributions at vent communities from 20 degrees S to 46 degrees N on the Mid-Ocean Ridge in the Pacific Ocean and at cold sulfide seeps in the Gulf of Mexico. Vent communities, consisting of at least 16 previously

J. Frederick Grassle

1985-01-01

32

Are hydrothermal vent animals living fossils?  

Microsoft Academic Search

Since their discovery in 1977, hydrothermal vent communities have provided many surprises about life in the deep sea and in extreme environments. It has been suggested that vent communities contain many living fossils and that deep-sea chemosynthetic environments, such as vents and hydrocarbon seeps, are buffered from extinction events that affect the photic zone. This hypothesis is based on the

Crispin T. S. Little; Robert C. Vrijenhoek

2003-01-01

33

Rapid Microbial Production of Filamentous Sulfur Mats at Hydrothermal Vents  

Microsoft Academic Search

During recent oceanographic cruises to Pacific hydrothermal vent sites (9N and the Guaymas Basin), the rapid microbial formation of filamentous sulfur mats by a new chemoautotrophic, hydrogen sulfide-oxidizing bacterium was documented in both in situ and shipboard experiments. Observations suggest that formation of these sulfur mats may be a factor in the initial colonization of hydrothermal surfaces by macrofaunal Alvinella

CRAIG D. TAYLOR; CARL O. WIRSEN; FRANCOISE GAILL

1999-01-01

34

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

E-print Network

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

Naveira Garabato, Alberto

35

Candy Chemosynthesis: Biochemistry of Hydrothermal Vents  

NSDL National Science Digital Library

In this activity, students will differentiate between requirements for life in extreme environments such as hydrothermal vents and other environments and will use soft candy as a model to create a visual image of chemicals involved in autotrophic nutrition. As they review the biochemistry of hydrothermal vents, they will discover what chemicals are used by autotrophs in extreme environments in the deep ocean and how these chemicals differ from those used by terrestrial autotrophs. They will also study a diagram showing how a hydrothermal vent (black smoker) acquires the elements and compounds that deep-sea autotrophs require.

36

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

Microsoft Academic Search

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

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

2010-01-01

37

ELSEVIER Earth and Planetary Science Letters 148 (1997) 69-9 I Hydrothermal vents near a mantle hot spot: the Lucky Strike vent  

E-print Network

EPSL ELSEVIER Earth and Planetary Science Letters 148 (1997) 69-9 I Hydrothermal vents near site found on crust that is dominated by a hot spot signature. Multiple hydrothermal vents occur over that the hydrothermal system has a long history and may have recently been rejuvenated. Fauna at the Lucky Strike vent

Langmuir, Charles H.

38

Vertebrate nutrition in a deep-sea hydrothermal vent ecosystem: Fatty acid and stable isotope evidence  

Microsoft Academic Search

The hydrothermal vent zoarcid fish Thermarces cerberus is a top predator that inhabits deep-sea hydrothermal vents on the East Pacific Rise (EPR). Bacterial chemoautotrophy at these sites 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 vent

D. W. Pond; A. E. Fallick; C. J. Stevens; D. J. Morrison; D. R. Dixon

2008-01-01

39

Chemoautotrophic Symbiosis in a Hydrothermal Vent Gastropod  

Microsoft Academic Search

An undescribed gastropod species collected from recently discovered deep-sea hydrothermal vents in the western Pacific contains endosymbiotic bacteria within specialized gill cells. The snails inhabit rocky vent openings where they are exposed directly to warm (2- 25°C) sulfide-rich (750 nM) water emitted from the vents. The gills of this snail contain elemental sulfur and high activities of enzymes catalyzing sulfide

JEFFREY L. STEIN; S. CRAIG GARY; ROBERT R. HESSLER; SUGURU OHTA; RUSSELL D. VETTER; JAMES J. CHILDRESS; HORST FELBECK

1988-01-01

40

Fine-Scale Three-Dimensional Mapping of a Deep-Sea Hydrothermal Vent Site Using the Jason ROV System  

Microsoft Academic Search

Using precise navigation, a computer-controlled remotely operated vehicle, and a variety of optical and acoustic imaging sensors, we created the most precise three-dimensional renderings ever made of an active hydrothermal vent field at a depth of 2400 meters on the deep sea floor. Data products included electronic and film photographs as well as three-dimensional sonar scans. We used these to

Dana R. Yoerger; Deborah S. Kelley; John R. Delaney

2000-01-01

41

Molecular ecology of hydrothermal vent microbial communities  

Microsoft Academic Search

The study of the structure and diversity of hydrothermal vent microbial communities has long been restricted to the morphological description of microorganisms and the use of enrichment culture-based techniques. Until recently the identification of the culturable fraction required the isolation of pure cultures followed by testing for multiple physiological and biochemical traits. However, peculiar inhabitants of the hydrothermal ecosystem such

Christian Jeanthon

2000-01-01

42

Automated Planning for Hydrothermal Vent Prospecting Using AUVs  

E-print Network

Automated Planning for Hydrothermal Vent Prospecting Using AUVs: RSMG Report 8 Zeyn A Saigol Thesis) to locate hydrothermal vents, which are superheated outgassings of water found on the ocean floor. Vents. Current methods for finding hydrothermal vents rely on manually defining an area for the AUV to perform

Yao, Xin

43

Hydrogen is an energy source for hydrothermal vent symbioses.  

PubMed

The discovery of deep-sea hydrothermal vents in 1977 revolutionized our understanding of the energy sources that fuel primary productivity on Earth. Hydrothermal vent ecosystems are dominated by animals that live in symbiosis with chemosynthetic bacteria. So far, only two energy sources have been shown to power chemosynthetic symbioses: reduced sulphur compounds and methane. Using metagenome sequencing, single-gene fluorescence in situ hybridization, immunohistochemistry, shipboard incubations and in situ mass spectrometry, we show here that the symbionts of the hydrothermal vent mussel Bathymodiolus from the Mid-Atlantic Ridge use hydrogen to power primary production. In addition, we show that the symbionts of Bathymodiolus mussels from Pacific vents have hupL, the key gene for hydrogen oxidation. Furthermore, the symbionts of other vent animals such as the tubeworm Riftia pachyptila and the shrimp Rimicaris exoculata also have hupL. We propose that the ability to use hydrogen as an energy source is widespread in hydrothermal vent symbioses, particularly at sites where hydrogen is abundant. PMID:21833083

Petersen, Jillian M; Zielinski, Frank U; Pape, Thomas; Seifert, Richard; Moraru, Cristina; Amann, Rudolf; Hourdez, Stephane; Girguis, Peter R; Wankel, Scott D; Barbe, Valerie; Pelletier, Eric; Fink, Dennis; Borowski, Christian; Bach, Wolfgang; Dubilier, Nicole

2011-08-11

44

Bacterial Diets of Primary Consumers at Hydrothermal Vents  

NASA Astrophysics Data System (ADS)

Chemical energy produced by mixing hydrothermal fluids and seawater supports dense biological communities on mid-ocean ridges. The base of the food web at deep-sea hydrothermal vents 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 vent-endemic macrofauna are heterotrophs that feed on free-living bacteria, protists, and other invertebrates. The most abundant and diverse group of primary consumers in hydrothermal vent 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 hydrothermal vent primary consumers and to track the flow of energy in hydrothermal vent communities, we employed molecular genetic techniques to identify the gut contents of four species of co-occurring hydrothermal vent gastropods, Eulepetopsis vitrea, Lepetodrilus elevatus, Lepetodrilus ovalis and Lepetodrilus pustulosus, collected from a single diffuse-flow hydrothermal vent site 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 hydrothermal vent 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 hydrothermal vents.

Govenar, B.; Shank, T. M.

2008-12-01

45

Dispatch from the Deep: Hydrothermal Vent Formation  

NSDL National Science Digital Library

This article discusses how hydrothermal vents are formed and why scientists monitor minute temperature changes around them. It details the writer's personal account of preparing temperature probes to be deployed for a year-long study, an explanation of deep sea vents and their hydrothermal nature, and why they seem to spew black smoke. The thermometers prepared by the writer help monitor the currents that pull the hot chimney water into the cold ocean to measure how fast it is cooled off and mixed. This information is used in the study of life at the vents and also to monitor changes in the effluent and to examine, over time, the chemistry of the mineral-rich waters that emerge from these vents.

46

New Type of Hydrothermal Vents Found  

NSDL National Science Digital Library

This CNN news article discusses the discovery of a new class of hydrothermal vents in the mid-Atlantic Ocean, called the Lost City, formed by heat generated when seawater reacts with mantle rocks rather than by volcanic activity. The article also notes the importance of the discovery to microbiologists, as some of these new vents were inhabited by single-cell organisms called thermophiles. Links to other CNN.com articles and resources are provided as well.

Walker, Alex

47

Ecology of deep-sea hydrothermal vent communities: A review  

Microsoft Academic Search

The present article reviews studies of the past 15 years of active and inactive hydrothermal vents. The focus of the discussion is on the ecology of the biological communities inhabiting hydrothermal vents. 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 hydrothermal vent systems

Richard A. Lutz; Michael J. Kennish

1993-01-01

48

Discovery of abundant hydrothermal venting on the ultraslow-spreading  

E-print Network

............................................................................................................................................................................. Submarine hydrothermal venting along mid-ocean ridges is an important contributor to ridge thermal structure predicted that the incidence of hydrothermal venting would be extremely low on ultraslow-spreading ridgesPublishing Group #12;active hydrothermal venting on the Gakkel ridge, which is the slowest spreading (0.6­1.3 cm yr

Graham, David W.

49

Belief Change Maximisation for Hydrothermal Vent Hunting Using Occupancy Grids  

E-print Network

Belief Change Maximisation for Hydrothermal Vent Hunting Using Occupancy Grids Zeyn Saigol floor for hydrothermal vents. The state of the art in these problems is information lookahead Vehicle (AUV) prospecting for hydrothermal vents, which are superheated outgassings of water found on mid

Yao, Xin

50

Radioisotopic studies of submarine hydrothermal vents  

NASA Astrophysics Data System (ADS)

The importance of mid-ocean ridge hydrothermal systems has been recognized for their role in the regulation of ocean and sediment chemistry, as well as for providing a chemosynthetic source of carbon which drives a unique population of animals found at hydrothermal vents. Despite the importance of these systems the rates, length, and depth scale of submarine hydrothermal processes are not precisely known because they are, for the most part, inaccessible to observational tools. We must therefore rely on indirect methods to quantify these processes. One way of investigating the rates, or timescales, of processes in a hydrothermal (or any natural) system is through the study and modeling of naturally occurring radioisotopes. Disequilibria among the naturally occurring radioactive decay series in vent fluids, associated mineral deposits, and overlying effluent plume have provided geochemical tools to investigate the rates of various processes occurring in submarine hydrothermal systems. Because the half-lives of the radioisotopes vary from days to many years, processes which encompass a wide range of spatial and temporal scales can be studied. This paper presents a review of methods that estimate the residence time of hydrothermal fluids in the ocean crust, establish the geochronology of seafloor sulfide deposits, investigate the rates of chemical reactions within hydrothermal effluent plumes, and derive the heat and mass flux from seafloor hydrothermal areas.

Kadko, David

1996-08-01

51

Stable isotopic compositions of hydrothermal vent organisms  

Microsoft Academic Search

Stable isotopic analyses were used to study trophic relationships in two communities of deep-sea hydrothermal vent organism in the Pacific Ocean. The community at Hanging Gardens on the East Pacific Rise (21N), sampled in 1985, is dominated by two species of vestimentiferan tubeworms; communities at Alice Springs and Snail Pits on the Marianas Back Arc Spreading Center (western Pacific), sampled

C. L. Dover; B. Fry

1989-01-01

52

Biogeography and Ecological Setting of Indian Ocean Hydrothermal Vents  

Microsoft Academic Search

Within the endemic invertebrate faunas of hydrothermal vents, five biogeographic provinces are recognized. Invertebrates at two Indian Ocean vent fields (Kairei and Edmond) belong to a sixth province, despite ecological settings and invertebrate-bacterial symbioses similar to those of both western Pacific and Atlantic vents. Most organisms found at these Indian Ocean vent fields have evolutionary affinities with western Pacific vent

C. L. Van Dover; S. E. Humphris; D. Fornari; C. M. Cavanaugh; R. Collier; S. K. Goffredi; J. Hashimoto; M. D. Lilley; A. L. Reysenbach; T. M. Shank; K. L. Von Damm; A. Banta; R. M. Gallant; D. Gtz; D. Green; J. Hall; T. L. Harmer; L. A. Hurtado; P. Johnson; Z. P. McKiness; C. Meredith; E. Olson; I. L. Pan; M. Turnipseed; Y. Won; C. R. Young; R. C. Vrijenhoek

2001-01-01

53

Deep-sea hydrothermal vent animals seek cool fluids in a highly variable thermal environment  

Microsoft Academic Search

The thermal characteristics of an organism's environment affect a multitude of parameters, from biochemical to evolutionary processes. Hydrothermal vents on mid-ocean ridges are created when warm hydrothermal fluids are ejected from the seafloor and mixed with cold bottom seawater; many animals thrive along these steep temperature and chemical gradients. Two-dimensional temperature maps at vent sites have demonstrated order of magnitude

Raymond W Lee; Verena Tunnicliffe; Miles D Lamare; Amanda E Bates

2010-01-01

54

High-Temperature Hydrothermal Vent Field of Kolumbo Submarine Volcano, Aegean Sea: Site of Active Kuroko-Type Mineralization  

NASA Astrophysics Data System (ADS)

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 hydrothermal vent field in the northeastern part of the Kolumbo crater floor, about 25,000 m2. Vent 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 vent fluids. Some vents 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 vent field and sulfide/sulfate mineralogy and geochemistry indicate on-going Kuroko-type mineralization in the Kolumbo submarine crater today.

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.

2006-12-01

55

Hydrothermal Vent System Unlike Any Seen Before Found in Atlantic  

NSDL National Science Digital Library

This web page is a press release form the University of Washington relating that a team of scientists led by Deborah Kelly, on Dec. 4 2000, discovered a new hydrothermal vent system that has been named "The Lost City". This unique hydrothermal field is located on an undersea mountain in the Atlantic Ocean and contains towers reaching 180 feet above the sea floor composed of silica and carbonate minerals. This is more than 100 feet taller than the average hydrothermal vents previously observed which are composed of iron and sulfur-based minerals. The web site has high-resolution images of these unique underwater features and has links to the investigators that participated in the discovery.

Clark, Cindy

56

Hydrothermal vent system unlike any seen before found in Atlantic  

NSDL National Science Digital Library

This web page is a press release form the University of Washington relating that a team of scientists led by Deborah Kelly, on Dec. 4 2000, discovered a new hydrothermal vent system that has been named ?The Lost City?. This unique hydrothermal field is located on an undersea mountain in the Atlantic Ocean and contains towers reaching180 feet above the sea floor composed of silica and carbonate minerals. This is more than 100 feet taller than the average hydrothermal vents previously observed which are composed of iron and sulfur-based minerals. The web site has high-resolution images of these unique underwater features and has links to the investigators that participated in the discovery.

Sandra Hines

57

Differential gene expression in the mussel Bathymodiolus azoricus from the Menez Gwen and Lucky Strike deep-sea hydrothermal vent sites  

NASA Astrophysics Data System (ADS)

The deep-sea hydrothermal vent mussel Bathymodiolus azoricus is a symbiont bearing bivalve that is found in great abundance at the Menez Gwen and Lucky Strike vent sites and in close vicinity off the Azores region near the Mid-Atlantic Ridge (MAR). The distinct relationships that vent 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 vent 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 vent 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 vent 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 hydrothermal vent site it is collected from and within the same collection site 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 hydrothermal vent animals issued from distinct deep-sea environmental sites based on immune and bacterial genes expressions.

Bettencourt, R.; Rodrigues, M. I.; Barros, I.; Cerqueira, T.; Freitas, C.; Costa, V.; Pinheiro, M.; Egas, C.; Santos, R. S.

2013-02-01

58

Biological factors influencing tissue compartmentalization of trace metals in the deep-sea hydrothermal vent bivalve Bathymodiolus azoricus at geochemically distinct vent sites of the Mid-Atlantic Ridge.  

PubMed

In this study, we investigated on concentrations of trace metals (Al, Cd, Mn, Co, and Hg) in the hydrothermal bivalve Bathymodiolus azoricus, a dominant species at most vent sites along the Mid-Atlantic Ridge (MAR), and in its endosymbiont bacteria and commensal parasite Branchipolynoe seepensis. Comparison of our results with data from the literature on non-hydrothermal bivalves suggests lack of "extreme" uptake of trace metals by B. azoricus, except for Hg concentration which exceeded manyfold previously reported values. Mussels collected from three geochemically distinct vent sites, Menez Gwen, Lucky Strike, and Rainbow, along the MAR showed significant differences in tissue concentration of metals. Proportionality of metals in soft tissues of mussels reflected variation of water chemistry at different vents, which in turn conserved the order of trace metal prevalence in undiluted fluids. There were significant tissue-specific differences in trace metal compartmentalization for all metals investigated. Byssus thread contained the highest metal concentration among examined tissues, and thus it is suggested to be an important detoxification route. Size-dependent differences in metal concentrations were detected only for Hg, revealing a general trend of small mussels accumulating more metal than big mussels. Endosymbiont bacteria are shown to exclusively sequester Al from the host gill and contribute to removal of other toxic metals in mussels from Menez Gwen. The commensal parasite present in all mussels from Lucky Strike had higher tissue concentrations of Mn, Al, and Co than the host gill, unlike Cd and Hg which were considerably lower in the former, and thus its role in detoxification remains unclear. Bioaccumulation potential of vent bivalves and associated organisms are quantified as concentration factors and compared to make inferences on the putative role of the endosymbiont bacteria and the commensal parasite in detoxification of trace metals. PMID:16199029

Kdr, Enik; Santos, Ricardo S; Powell, Jonathan J

2006-06-01

59

Automated Planning for Hydrothermal Vent Prospecting Using AUVs  

E-print Network

Automated Planning for Hydrothermal Vent Prospecting Using AUVs Zeyn A Saigol A thesis submitted of searching the ocean floor for hydrothermal vents, using autonomous under- water vehicles (AUVs). This is a hard problem because the AUV's sensors cannot directly measure the range or bearing to vents

Yao, Xin

60

Optical Detection of Organic Chemical Biosignatures at Hydrothermal Vents  

NASA Technical Reports Server (NTRS)

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 hydrothermal vent sites 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 vent, as well as direct detection of organisms, both microbial and microscopic. We also were able to detect organic material issuing directly from vent chimneys, measure the organic signature of the water column as we ascended, and passively observe the emission of light directly from some vents.

Conrad, P. G.; Lane, A. L.; Bhartia, R.; Hug, W. H.

2004-01-01

61

Hydrothermal venting along Earth's fastest spreading center: East Pacific Rise,  

E-print Network

Hydrothermal venting along Earth's fastest spreading center: East Pacific Rise, 27.5°­32.3°S E. T by a hydrothermal plume. Plume chemistry mostly reflected discharge from mature vent fields apparently unperturbed March/April 1998 we conducted detailed mapping and sampling of hydrothermal plumes along six segments

Bohnenstiehl, Delwayne

62

Spatial and temporal population genetics at deep-sea hydrothermal vents along the East Pacific Rise and Galpagos Rift  

E-print Network

Ecological processes at deep-sea hydrothermal vents on fast-spreading mid-ocean ridges are punctuated by frequent physical disturbance. Larval dispersal among disjunct vent sites facilitates the persistence of sessile ...

Fusaro, Abigail Jean

2008-01-01

63

Ecology of deep-sea hydrothermal vent communities: A review  

SciTech Connect

The present article reviews studies of the past 15 years of active and inactive hydrothermal vents. The focus of the discussion is on the ecology of the biological communities inhabiting hydrothermal vents. 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 hydrothermal vent systems to geology. Future directions for hydrothermal vent research are suggested. Since many vent populations are dependent on hydrothermal fluids and are consequently unstable, both short- and long-term aspects of the ecology of the vent organisms and the influence of chemical and geological factors on the biology of vent systems need to be established. 200 refs., 28 figs.

Lutz, R.A.; Kennish, M.J. (Rutgers Univ., New Brunswick, NJ (United States))

1993-08-01

64

The use of photo-mosaics, bathymetry and sensor data into geographic information system for site description and faunal distribution analysis at the Menez Gwen Hydrothermal vent field  

NASA Astrophysics Data System (ADS)

The Menez Gwen hydrothermal vent 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 sites of active venting at Menez Gwen are still under described, and it is not possible to get a global picture of the sites 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, site 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 hydrothermal vent system, high-resolution photo-mosaics of several sites of hydrothermal 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 n237868), and funded through DFG Research Center / Excellence Cluster "The Ocean in the Earth System".

Marcon, Y.; Sahling, H.; Bohrmann, G.

2012-04-01

65

High-Resolution Photo-Mosaicing of the Rosebud Hydrothermal Vent Site and Surrounding Lava Flows, Galapagos Rift 86W: Techniques and Interpretations  

NASA Astrophysics Data System (ADS)

The Rosebud hydrothermal vent field was discovered in May 2002 in the Galapagos Rift near 86W during a series of Alvin dives and ABE autonomous vehicle surveys. Vertical-incidence digital imaging using a 3.1 Mpixel digital camera and strobe illumination from altitudes of 3-5m was carried out during the Alvin dives. A complete survey of the Rosebud vent site was carried out on Alvin Dive 3790. Submersible position was determined by post-cruise integration of 1.2 MHz bottom-lock Doppler sonar velocity data logged at 5Hz, integrated with heading and attitude data from a north-seeking fiber-optic gyroscope logged at 10Hz, and initialized with a surveyed-in long-baseline transponder navigation system providing geodetic position fixes at 15s intervals. The photo-mosaicing process consisted of three main stages: pre-processing, pair-wise image co-registration, and global alignment. Excellent image quality allowed us to avoid lens distortion correction, so images only underwent histogram equalization. Pair-wise co-registration of sequential frames was done partially automatically (where overlap exceeded 70 percent we employed a frequency-domain based technique), and partially manually (when overlap did not exceed 15 percent and manual feature extraction was the only way to find transformations relating the frames). Partial mosaics allowed us to determine which non-sequential frames had substantial overlap, and the corresponding transformations were found via feature extraction. Global alignment of the images consisted of construction of a sparse, nonlinear over-constrained system of equations reflecting positions of the frames in real-world coordinates. This system was solved using least squares, and the solution provided globally optimal positions of the frames in the overall mosaic. Over 700 images were mosaiced resulting in resolution of ~3 mm per pixel. The mosaiced area covers approximately 50 m x 60 m and clearly shows several biological zonations and distribution of lava flow morphologies, including what is interpreted as the contact between older lobate lava and the young sheet flow that hosts Rosebud vent communities. Recruitment of tubeworms, mussels, and clams is actively occurring at more than five locations oriented on a NE-SW trend where vent emissions occur through small cracks in the sheet flow. Large-scale views of seafloor hydrothermal vent sites, such as the one produced for Rosebud, are critical to properly understanding spatial relationships between hydrothermal biological communities, sites of focused and diffuse fluid flow, and the complex array of volcanic and tectonic features at mid-ocean ridge crests. These high-resolution perspectives are also critical to time-series studies where quantitative documentation of changes can be related to variations in hydrothermal, magmatic and tectonic processes.

Rzhanov, Y.; Mayer, L.; Fornari, D.; Shank, T.; Humphris, S.; Scheirer, D.; Kinsey, J.; Whitcomb, L.

2003-12-01

66

Diffuse flow from hydrothermal vents. Doctoral thesis  

SciTech Connect

The effluent from a collection of diffuse hydrothermal vents 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 hydrothermal vents 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 hydrothermal 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.

Trivett, D.A.

1991-08-01

67

Metal influence on metallothionein synthesis in the hydrothermal vent mussel Bathymodiolus thermophilus  

E-print Network

Metal influence on metallothionein synthesis in the hydrothermal vent mussel Bathymodiolus;2 Abstract: The present study reports on the metallothionein expression in the hydrothermal vent mussel and conserved throughout the animal kingdom. The hydrothermal vent environment presents peculiarities (high

Paris-Sud XI, Université de

68

Hydrothermal vents is Lake Tanganyika, East African Rift system  

SciTech Connect

Sublacustrine hydrothermal vents 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 hydrothermal vents 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 hydrothermal fluids and sediments. Veins of massive sulfides 1-10 cm thick (pyrite and marcasite banding) were found associated with vents at the Pemba site. At Cape Banza, active vents are characterized by 1-70-cm-high aragonite chimneys, and there are microcrystalline pyrite coatings on the walls of hydrothermal pipes. Hydrothermal fluid end members show distinctive compositions at the two sites. 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 vents. 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 hydrothermal 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.

Tiercelin, J.J. [Universite de Bretagne Occidentale, Brest (France)] [Universite de Bretagne Occidentale, Brest (France); Pflumio, C.; Castrec, M. [Universite Paris VI, Paris (France)] [and others] [Universite Paris VI, Paris (France); and others

1993-06-01

69

Hydrothermal vents in Lake Tanganyika, East African, Rift system  

Microsoft Academic Search

Sublacustrine hydrothermal vents 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 hydrothermal vents down to a depth

Jean-Jacques Tiercelin; Catherine Pflumio; Maryse Castrec; Jacques Boulgue; Pascal Gente; Jol Rolet; Christophe Coussement; Karl O. Stetter; Robert Huber; Sony Buku; Wafula Mifundu

1993-01-01

70

Biogeography and ecological setting of Indian Ocean hydrothermal vents.  

PubMed

Within the endemic invertebrate faunas of hydrothermal vents, five biogeographic provinces are recognized. Invertebrates at two Indian Ocean vent fields (Kairei and Edmond) belong to a sixth province, despite ecological settings and invertebrate-bacterial symbioses similar to those of both western Pacific and Atlantic vents. Most organisms found at these Indian Ocean vent fields have evolutionary affinities with western Pacific vent faunas, but a shrimp that ecologically dominates Indian Ocean vents closely resembles its Mid-Atlantic counterpart. These findings contribute to a global assessment of the biogeography of chemosynthetic faunas and indicate that the Indian Ocean vent community follows asymmetric assembly rules biased toward Pacific evolutionary alliances. PMID:11557843

Van Dover, C L; Humphris, S E; Fornari, D; Cavanaugh, C M; Collier, R; Goffredi, S K; Hashimoto, J; Lilley, M D; Reysenbach, A L; Shank, T M; Von Damm, K L; Banta, A; Gallant, R M; Gotz, D; Green, D; Hall, J; Harmer, T L; Hurtado, L A; Johnson, P; McKiness, Z P; Meredith, C; Olson, E; Pan, I L; Turnipseed, M; Won, Y; Young, C R; Vrijenhoek, R C

2001-10-26

71

Raman Spectroscopy at Deep-Sea Hydrothermal Vents  

NASA Astrophysics Data System (ADS)

In this presentation we will describe the development and optimization of a custom submersible Raman instrument that was successfully deployed in one of the harshest environments on the planet, hydrothermal vent systems. The primary objective of this project was to develop a multi-platform, broad spectral chemical sensor for investigating hydrothermal processes in the deep ocean. Mid-ocean ridge hydrothermal systems are complex and highly variable with extreme thermal and chemical gradients which support a diverse ecosystem of micro and macro fauna, specially adapted to thrive within variable mixtures of hydrothermal fluid and seawater. Hydrothermal inputs have large effects on global geochemical cycles yet our understanding of the temporal variability of these contributions to the ocean needs to be further investigated. Towards this goal a sensitive, in situ Raman spectroscopy instrument was developed for extended geochemical analysis of hydrothermal systems. Raman spectroscopy is a highly selective, full spectral optical technique capable of non-invasively identifying and quantifying numerous organic and inorganic species in a deep ocean environment. Advantages of Raman spectroscopy for in situ analysis include broad spectral range, no sample preparation and fast analysis times. The Raman instrument developed was designed to maximize sensitivity and spectral breadth to ensure identification and quantification of a vast array of geochemical species in the deep. The custom high resolution, high sensitivity Raman instrument is fiber-optically coupled to a high temperature and pressure Raman Ballprobe immersion optic. This novel probe is designed to accurately collect Raman data from turbulent and opaque samples at high temperatures and pressures. This instrument was successfully deployed by DSV/Alvin to numerous diffuse and high temperature vent sites at the Main Endeavour Field of the Juan de Fuca Ridge. A variety of vents were sampled and we present the first qualitative Raman spectra of chemical species in actively venting fluid. Currently we are seeking to fully identify and quantitate the chemical species in both diffuse and high temperature vent Raman data, optimize algorithms to maintain calibration in this extreme environment and redesign the instrument for multiple month deployment.

Thompson, W. J.; Marquardt, B. J.; Lilley, M. D.

2008-12-01

72

A Biogeographical Perspective of the Deep-Sea Hydrothermal Vent Fauna  

Microsoft Academic Search

Biogeography seeks to distinguish patterns in the distribution of species and to determine causal processes. Hydrothermal vent habitats have several properties that invite biogeographic studies: constrained to active deep-sea ocean ridges, known in most oceans and anticipated in the rest, patchy in distribution, extreme conditions and a limited group of inhabitants. Biologists have studied 30 vent sites mostly in the

Verena Tunnicliffe; Andrew G. McArthur; Damhnait McHugh

1998-01-01

73

Metabolic and blood characteristics of the hydrothermal vent tube-worm Riftia pachyptila  

Microsoft Academic Search

Specimens of the hydrothermal vent pogonophoran Riftia pachyptila Jones were collected by submersible at a depth of 2 600 m at the 21N hydrothermal vent site on the East Pacific Rise (2050'N, 10906'W) in April and May of 1982. The worms were maintained in pressurized aquaria for up to 45 d for metabolic studies. Consumption of O2 was regulated down

J. J. Childress; A. J. Arp; C. R. Fisher

1984-01-01

74

Deep-Sea Hydrothermal-Vent Sampler  

NASA Technical Reports Server (NTRS)

An apparatus is being developed for sampling water for signs of microbial life in an ocean hydrothermal vent at a depth of as much as 6.5 km. Heretofore, evidence of microbial life in deep-sea hydrothermal vents 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 hydrothermal- vent 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 hydrothermal 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 vent 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.

Behar, Alberto E.; Venkateswaran, Kasthur; Matthews, Jaret B.

2008-01-01

75

Geomicrobiology of Hydrothermal Vents in Yellowstone Lake: Phylogenetic and Functional Analysis suggest Importance of Geochemistry (Invited)  

NASA Astrophysics Data System (ADS)

Yellowstone Lake (Yellowstone National Park, WY, USA) is a large, high-altitude, fresh-water lake that straddles the most recent Yellowstone caldera, and is situated on top of significant hydrothermal activity. An interdisciplinary study is underway to evaluate the geochemical and geomicrobiological characteristics of several hydrothermal vent environments sampled using a remotely operated vehicle, and to determine the degree to which these vents may influence the biology of this young freshwater ecosystem. Approximately six different vent systems (locations) were sampled during 2007 and 2008, and included water obtained directly from the hydrothermal vents as well as biomass and sediment associated with these high-temperature environments. Thorough geochemical analysis of these hydrothermal environments reveals variation in pH, sulfide, hydrogen and other potential electron donors that may drive primary productivity. The concentrations of dissolved hydrogen and sulfide were extremely high in numerous vents sampled, especially the deeper (30-50 m) vents located in the Inflated Plain, West Thumb, and Mary Bay. Significant dilution of hydrothermal fluids occurs due to mixing with surrounding lake water. Despite this, the temperatures observed in many of these hydrothermal vents range from 50-90 C, and elevated concentrations of constituents typically associated with geothermal activity in Yellowstone are observed in waters sampled directly from vent discharge. Microorganisms associated with elemental sulfur mats and filamentous streamer communities of Inflated Plain and West Thumb (pH range 5-6) were dominated by members of the deeply-rooted bacterial Order Aquificales, but also contain thermophilic members of the domain Archaea. Assembly of metagenome sequence from the Inflated Plain vent biomass and to a lesser extent, West Thumb vent biomass reveal the importance of Sulfurihydrogenibium-like organisms, also important in numerous terrestrial geothermal outflow channels of YNP. Analysis of functional genes present in the consensus metagenome sequence representing these populations indicate metabolic potential for oxidation of reduced sulfur and hydrogen, both of which are present at high concentrations in these vent ecosystems. Metagenome sequence of biomass associated with sediments from hydrothermal vents at Mary Bay (50 m depth) suggest greater archaeal and bacterial diversity in this environment, which may be due to higher concentrations of hydrogen, iron, and manganese measured in these environments. Results from metagenome sequence and modest 16S rRNA gene surveys from hydrothermal vent biomass indicate that several groups of novel thermophilic archaea inhabit these sites, and in many cases, are represented by organisms not found in YNP terrestrial geothermal environments that have been characterized to date. The hydrothermal vents from Inflated Plain and West Thumb indicate a linkage between various geochemical attributes (sulfide, hydrogen) and the metabolic potential associated with dominant Aquificales populations present in these communities.

Inskeep, W. P.; Macur, R.; Jay, Z.; Clingenpeel, S.; Tenney, A.; Lavalvo, D.; Shanks, W. C.; McDermott, T.; Kan, J.; Gorby, Y.; Morgan, L. A.; Yooseph, S.; Varley, J.; Nealson, K.

2010-12-01

76

Hydrothermal vent clam and tube worm /sup 13/C//sup 12/C: further evidence of nonphotosynthetic food sources  

SciTech Connect

The stable carbon isotope ratios in clam mantle tissues taken from both Galapagos and 21/sup 0/N hydrothermal vent sites were similar to the unusually low ratios of carbon-13 to carbon-12 previously reported for a Galapagos hydrothermal vent mussel. In marked contrast to these bivalues, vestimentiferan worm tissues from a Galapagos vent 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 vent animals, and that at least one of these pathways is common to two geographically separated vent sites.

Rau, G.H.

1981-07-17

77

Decline of a Hydrothermal Vent Field - Escanaba Trough 12 Years Later  

NASA Astrophysics Data System (ADS)

Hydrothermal venting was discovered in Escanaba Trough, the southern sediment-covered portion of the Gorda Ridge, in 1988. Large pyrrhotite-rich massive sulfide mounds are abundant at each of the volcanic/intrusive centers that have been investigated in Escanaba Trough, but the only area of known hydrothermal venting is the NESCA site along the ridge axis at 41\\deg N. Hydrothermal fluids venting at 217\\deg C and 108\\deg C were sampled in 1988 on two sulfide mounds separated by about 275 m. The end-member fluid compositions were indistinguishable within analytical errors. Several sulfide mounds were observed in 1988 which had diffusely venting low temperature (< 20\\deg C) fluids that supported extensive vent communities dominated by fields of Ridgia. Nine holes were drilled in the NESCA area in 1996 on ODP Leg 169, including Hole 1036I that penetrated to basaltic basement at 405 m below sea floor (mbsf). Surveys of the area using the drill string camera located only one area of active venting at the same mound where 217\\deg C vent fluids were sampled from two active vents in 1988. Drill hole 1036A was spudded between the two active vents on this sulfide mound (approximately 4 and 8 m away) and penetrated to 115 mbsf. The NESCA site was revisited in 2000 using MBARI's R/V Western Flyer and ROV Tiburon. The hydrothermal vents appeared essentially identical to observations made from the drill string camera in 1996 despite the presence of a drill hole within meters of the two vents. The maximum vent temperature measured in 2000 was 212\\deg C. Fluid samples have major element and isotopic compositions very similar to those collected in 1988. The vent fluids have higher methane ( ~19 mmol/kg) than those from the geologically similar Middle Valley vent field, but lower values than those at Guaymas Basin. Drill hole 1036A was weakly venting, but the diffuse hydrothermal fluids could not be sampled with the equipment available. The walls of the drill hole were colonized by palm worms, limpets, and snails. Four other drill holes showed no hydrothermal flow nor visible evidence of down hole recharge. Mapping with Tiburon confirmed that the extent of hydrothermal venting at NESCA decreased dramatically since 1988. Formerly extensive colonies of Ridgia had vanished leaving no trace of their presence. Although hydrothermal venting has collapsed to a single mound, the temperature and composition of the fluids remained nearly unchanged. This is curious given that sediment pore fluids analyzed on Leg 169 included both high salinity and low salinity components of phase separated hydrothermal fluids in the shallow subsurface indicating that the hydrothermal field must have had a relatively recent (relative to the rate of pore fluid diffusion) high temperature history. Hydrothermal fluids presently venting at this site must be derived from an essentially homogeneous, approximately 215\\degC fluid reservoir that has declined in its fluid output on a decadal scale, but has not undergone significant changes in temperature and composition. Venting at the seafloor does not seem to have been affected by drilling in the hydrothermal field.

Zierenberg, R. A.; Clague, D. A.; Davis, A. S.; Lilley, M. D.; McClain, J. S.; Olson, E. S.; Ross, S. L.; Von Damm, K. L.

2001-12-01

78

Increased diversity of sessile epibenthos at subtidal hydrothermal vents: seven hypotheses based on observations at Milos Island, Aegean Sea  

Microsoft Academic Search

Research on subtidal hydrothermal vent ecosystems at Milos, Hellenic Volcanic Arc (Aegean Sea), suggested that vent activity increased the species richness of sessile epibenthic assemblages. Based on 303 species found in 6 sites (3 close to vents, 3 farther away), the present paper uses correspondence analysis and species\\/samples curves to examine the species composition and richness of these assemblages. Differences

Carlo Nike Bianchi; Paul R. Dando; Carla Morri

2011-01-01

79

Expansion of the geographic distribution of a novel lineage of ?-Proteobacteria to a hydrothermal vent site on the Southern East Pacific Rise  

Microsoft Academic Search

The diversity associated with a microbial mat sample collected from a deep-sea hydrothermal vent on the Southern East Pacific Rise was determined using a molecular phylogenetic approach based on the comparison of sequences from the small subunit ribosomal RNA gene (16S rDNA). The DNA was extracted from the sample and the 16S rDNA was amplified by PCR. Sixteen different phylotypes

Krista Longnecker; Anna-Louise Reysenbach

2001-01-01

80

Heat flux measured acoustically at Grotto Vent, a hydrothermal vent cluster on the Endeavour Segment, Juan de Fuca Ridge  

NASA Astrophysics Data System (ADS)

Over the past several decades, quantifying the heat output has been a unanimous focus of studies at hydrothermal vent fields discovered around the global ocean. Despite their importance, direct measurements of hydrothermal heat flux are very limited due to the remoteness of most vent sites and the complexity of hydrothermal venting. Moreover, almost all the heat flux measurements made to date are snapshots and provide little information on the temporal variation that is expected from the dynamic nature of a hydrothermal system. The Cabled Observatory Vent Imaging Sonar (COVIS, https://sites.google.com/a/uw.edu/covis/) is currently connected to the Endeavour node of the NEPTUNE Canada observatory network (http://www.neptunecanada.ca) to monitor the hydrothermal plumes issuing from a vent cluster (Grotto) on the Endeavour Segment of the Juan de Fuca Ridge. COVIS is acquiring a long-term (20-months to date) time series of the vertical flow rate and volume flux of the hydrothermal plume above Grotto through the Doppler analysis of the acoustic backscatter data (Xu et al., 2013). We then estimate the plume heat flux from vertical flow rate and volume flux using our newly developed inverse method. In this presentation, we will briefly summarize the derivation of the inverse method and present the heat-flux time series obtained consequently with uncertainty quantification. In addition, we compare our heat-flux estimates with the one estimated from the plume in-situ temperatures measured using a Remotely Operative Vehicle (ROV) in 2012. Such comparison sheds light on the uncertainty of our heat flux estimation. Xu, G., Jackson, D., Bemis, K., and Rona, P., 2013, Observations of the volume flux of a seafloor hydrothermal plume using an acoustic imaging sonar, Geochemistry, Geophysics Geosystems, 2013 (in press).

Xu, G.; Jackson, D. R.; Bemis, K. G.; Rona, P. A.

2013-12-01

81

Hydrothermal vent clam and tube worm ¹³C\\/¹²C: further evidence of nonphotosynthetic food sources  

Microsoft Academic Search

The stable carbon isotope ratios in clam mantle tissues taken from both Galapagos and 21°N hydrothermal vent sites were similar to the unusually low ratios of carbon-13 to carbon-12 previously reported for a Galapagos hydrothermal vent mussel. In marked contrast to these bivalues, vestimentiferan worm tissues from a Galapagos vent had isotope ratios that were higher than those of open

G. H. RAU

1981-01-01

82

Hydrothermal vent fields and chemosynthetic biota on the world's deepest seafloor spreading centre  

PubMed Central

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 hydrothermal venting, and the biogeography of vent fauna. Here we report the discovery of two hydrothermal vent fields on the Mid-Cayman spreading centre. The Von Damm Vent Field is located on the upper slopes of an oceanic core complex at a depth of 2,300?m. High-temperature venting in this off-axis setting suggests that the global incidence of vent fields may be underestimated. At a depth of 4,960?m on the Mid-Cayman spreading centre axis, the Beebe Vent Field emits copper-enriched fluids and a buoyant plume that rises 1,100?m, consistent with >400?C venting from the world's deepest known hydrothermal system. At both sites, a new morphospecies of alvinocaridid shrimp dominates faunal assemblages, which exhibit similarities to those of Mid-Atlantic vents. PMID:22233630

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; Hhnerbach, 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

2012-01-01

83

Chemistry of hydrothermal solutions from Pele's Vents, Loihi Seamount, Hawaii  

Microsoft Academic Search

Hydrothermal fluids were sampled from Pele's Vents on the summit of Loihi Seamount, an intraplate, hotspot volcano, on four occasions from February 1987 to September 1990. The warm ( 31C) vent solutions are enriched in dissolved Si, CO 2 , H 2 S, alkalinity, K + , Li + , Rb + , Ca 2+ , Sr 2+ , Ba

P. N. Sedwick; G. M. McMurtry; J. D. MacDougall

1992-01-01

84

Deep-sea primary production at the Galapagos hydrothermal vents  

SciTech Connect

Dense animal populations surrounding recently discovered hydrothermal vents 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 vents is liberated during oxidation and used for the reduction of carbon dioxide to organic matter by chemosynthetic bacteria.

Karl, D.M. (Univ. of Hawaii, Honolulu); Wirsen, C.O.; Jannasch, H.W.

1980-03-21

85

Growth and Phylogenetic Properties of Novel Bacteria Belonging to the Epsilon Subdivision of the Proteobacteria Enriched from Alvinella pompejana and Deep-Sea Hydrothermal Vents  

Microsoft Academic Search

Recent molecular characterizations of microbial communities from deep-sea hydrothermal sites indicate the predominance of bacteria belonging to the epsilon subdivision of Proteobacteria (epsilon Proteobacteria). Here, we report the first enrichments and characterizations of four epsilon Proteobacteria that are directly associated with Alvinella pompejana, a deep sea hydrothermal vent polychete, or with hydrothermal vent chimney samples. These novel bacteria were moderately

BARBARA J. CAMPBELL; CHRISTIAN JEANTHON; JOEL E. KOSTKA; GEORGE W. LUTHER; S. CRAIG CARY

2001-01-01

86

Isolation and Stability of Distinct Subsurface Microbial Communities Associated with Two Hydrothermal Vent Systems  

NASA Astrophysics Data System (ADS)

Subseafloor microbial communities may be important in global primary production and biogeochemical cycling. However, too little is known about the physiological and phylogenetic diversity and activity of these communities to assess this potential, and understanding the temporal and spatial variability in microbial community structure is critical. The microbial community structure of five geographically distinct hydrothermal vents located within the Axial Seamount caldera, and four geographically distinct vents within the Main Endeavour Field, Juan de Fuca Ridge, were examined over six years. Terminal restriction fragment length polymorphism (tRFLP) and 16S rRNA gene sequence analyses were used to determine the bacterial and archaeal diversity, and the statistical software Primer was used to compare vent microbiology, temperature and fluid chemistry. Statistical analysis of vent fluid temperature and chemical composition shows that there are significant differences between vents in any year, and persistent differences in composition between one of the Axial vents compared to the rest of the vents. For the majority of vents, however, the fluid composition changed over time such that separate vents do not maintain a statistically distinct composition. In contrast, the subseafloor microbial communities associated with individual vents also changed from year to year but each location maintained a distinct community structure (based on tRFLP and 16S rRNA gene sequence analyses) that was significantly different and greater than 60-percent dissimilar from all other vents included in this study. At Axial, epsilon-proteobacterial microdiversity is shown to be important in distinguishing vent communities. The deeper, high-temperature archaeal communities have more overlap between sites. We propose that persistent venting at many diffuse sites over time creates the potential to isolate and stabilize diverse microbial community structures between vents. Variation in dilution patterns along discrete flow channels feeding diffuse seafloor vents promotes microbial diversity and uniqueness of different diffuse vent sites, especially among the thermophilic Bacteria within the 5-50C sub-seafloor temperature range.

Opatkiewicz, A. D.; Butterfield, D. A.; Baross, J. A.

2008-12-01

87

Surface-Generated Mesoscale Eddies Transport Deep-Sea Products from Hydrothermal Vents  

E-print Network

1 Surface-Generated Mesoscale Eddies Transport Deep-Sea Products from Hydrothermal Vents Diane K of surface-generated mesoscale eddies in the transport of hydrothermal vent efflux and of vent larvae away.1126/science.1201066 #12;2 Hydrothermal vents are hot spots for geological, geochemical, and biological

Paris-Sud XI, Université de

88

Geochemistry of Champagne Hot Springs shallow hydrothermal vent field and associated sediments, Dominica, Lesser Antilles  

E-print Network

Geochemistry of Champagne Hot Springs shallow hydrothermal vent field and associated sediments and precipitate chemistry, as well as comparing the submarine vent chemistry with nearby on-land hydrothermal hydrothermal venting, located approximately 40 m to the north of CHS. This area consists of hydrothermally

Pichler, Thomas

89

Euryhaline Halophilic Microorganisms From the Suiyo Seamount Hydrothermal Vents.  

NASA Astrophysics Data System (ADS)

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 vents and seeps, and from Antarctic sea ice and terrains. We have isolated the euryhaline strains independently from a Mid-Atlantic Ridge vent 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 hydrothermal vent 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-vent. To test this hypothesis, isolation and characterization of euryhaline halophiles from the Suiyo Seamount hydrothermal vents were conducted the drill-cored rock samples from the sites APSK-02, 03, and 07 and the filter-trapped fluid particle samples from the sites 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.

Okamoto, T.; Kimura, H.; Maruyama, A.; Naganuma, T.

2002-12-01

90

Hydrothermal vents of Yellowstone Lake, Yellowstone National Park, Wyoming  

SciTech Connect

Hydrothermal vent systems within Yellowstone Lake are located within the Yellowstone caldera in the northeastern and West Thumb sections of the lake. The vent systems lie within areas of extremely high geothermal gradients (< 1,000 C/km) in the lake sediments and occur as clusters of individual vents that expel both hydrothermal fluids and gas. Regions surrounding the vents are colonized by unique, chemotropic biologic communities and suggest that hydrothermal input plays an important role in the nutrient dynamics of the lake's ecosystem. The main concentration of hydrothermal 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. Hydrothermal vents 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. Hydrothermal vents 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 hydrothermal fluids encounter a semi-permeable cap of lake sediments. Upwardly convecting hydrothermal 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.

Kaplinski, M.A.; Morgan, P. (Northern Arizona Univ., Flagstaff, AZ (United States). Geology Dept.)

1993-04-01

91

Deep sea hydrothermal vents. (Latest citations from Oceanic abstracts). Published Search  

SciTech Connect

The bibliography contains citations concerning biological, chemical, and geophysical investigations of seafloor hydrothermal vents. Biological community descriptions, primary production and growth studies, the nature and occurrence of mineral deposits, and the structure and morphology of vent systems are among the topics discussed. Specific site studies, and general investigations are considered. (Contains a minimum of 157 citations and includes a subject term index and title list.)

Not Available

1994-04-01

92

Characterizing the distribution and rates of microbial sulfate reduction at Middle Valley hydrothermal vents  

PubMed Central

Few studies have directly measured sulfate reduction at hydrothermal vents, and relatively little is known about how environmental or ecological factors influence rates of sulfate reduction in vent environments. A better understanding of microbially mediated sulfate reduction in hydrothermal vent 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 hydrothermal vents in the Middle Valley vent 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 sites, 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 thatwithin anaerobic niches of hydrothermal depositsheterotrophic 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 vents. PMID:23535916

Frank, Kiana L; Rogers, Daniel R; Olins, Heather C; Vidoudez, Charles; Girguis, Peter R

2013-01-01

93

An authoritative global database for active submarine hydrothermal vent fields  

NASA Astrophysics Data System (ADS)

The InterRidge Vents Database is available online as the authoritative reference for locations of active submarine hydrothermal vent 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 vent fields. The number of known active vent 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 vent 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 vent fields within exclusive economic zones, consequently reducing the proportion known in high seas to one third. The increase in known vent fields reflects a number of factors, including increased national and commercial interests in seafloor hydrothermal 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 vent fields in areas granted or pending applications for mineral prospecting and 8% in marine protected areas.

Beaulieu, Stace E.; Baker, Edward T.; German, Christopher R.; Maffei, Andrew

2013-11-01

94

A deep-sea hydrothermal vent community dominated by Stauromedusae  

NASA Astrophysics Data System (ADS)

A dense population of stauromedusan scyphozoans (morphologically similar to previously described species within the genus Lucernaria) was encountered in a previously undocumented area of hydrothermal activity along the crest of the East Pacific Rise (Lat. 2050.304'N; Long. 10905.422'W; depth of 2605 m). A few galatheid ( Munidopsis subsquamosa) and bythograeid ( Bythograea thermydron) crabs and occasional anemones ( Cyananthea sp.) were the only other vent-associated megafauna observed within the region. This report represents: (1) the first documented occurrence of a biological community dominated by Stauromedusae at an active hydrothermal vent; (2) one of the deepest reported occurrences of Stauromedusae in the world's oceans; and (3) documentation of the existence of a species within a class (Scyphozoa) of organisms that thus far has not been reported from hydrothermal vents or other reducing environments.

Lutz, Richard A.; Desbruyres, Daniel; Shank, Timothy M.; Vrijenhoek, Robert C.

1998-01-01

95

Sulfur Isotope Geochemistry of the Lost City Hydrothermal Vent Fluids  

Microsoft Academic Search

At the Lost City Hydrothermal Vent Field (Mid-Atlantic Ridge, 30 N), reactions between seawater and ultramafic rocks produce high alkaline (pH 9 to 11) fluids that are venting at temperatures of 40 to 90 C and result in the formation of up to 60m tall carbonate-brucite structures. The fluids are enriched in hydrogen, methane and other hydrocarbons, and support dense

G. L. Frueh-Green; S. M. Bernasconi; D. A. Butterfield; D. S. Kelley

2004-01-01

96

We're in Hot Water Now: Hydrothermal Vents  

NSDL National Science Digital Library

In this National Geographic lesson, students will use National Geographic's Yellowstone internet module to learn about the processes that drive geysers. The activity involves learning about hydrothermal vents and uniquely adapted animals that live near the vents with the aid of pictures and maps. The activity concludes with an opportunity to create an aquarium exhibit which showcases some of these animals and their special adaptations. The website also includes related links and extensions for the project.

National Geographic Xpeditions

97

The stability of amino acids at submarine hydrothermal vent temperatures  

NASA Technical Reports Server (NTRS)

It has been postulated that amino acid stability at hydrothermal vent 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 vent conditions.

Bada, Jeffrey L.; Miller, Stanley L.; Zhao, Meixun

1995-01-01

98

A ubiquitous thermoacidophilic archaeon from deep-sea hydrothermal vents  

USGS Publications Warehouse

Deep-sea hydrothermal vents 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 hydrothermal 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 venting sulphide structures is generally low (pH < 4.5), yet no extreme thermoacidophile has been isolated from vent deposits. Culture-independent surveys based on ribosomal RNA genes from deep-sea hydrothermal deposits have identified a widespread euryarchaeotal lineage, DHVE2 (deep-sea hydrothermal vent 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 vents. ?? 2006 Nature Publishing Group.

Reysenbach, A.-L.; Liu, Y.; Banta, A.B.; Beveridge, T.J.; Kirshtein, J.D.; Schouten, S.; Tivey, M.K.; Von Damm, K. L.; Voytek, M.A.

2006-01-01

99

Discovery of a new hydrothermal vent based on an underwater, high-resolution geophysical survey  

NASA Astrophysics Data System (ADS)

A new hydrothermal vent site in the Southern Mariana Trough has been discovered using acoustic and magnetic surveys conducted by the Japan Agency for Marine-Earth Science and Technology's (JAMSTEC) autonomous underwater vehicle (AUV), Urashima. The high-resolution magnetic survey, part of a near-bottom geophysical mapping around a previously known hydrothermal vent site, the Pika site, during the YK09-08 cruise in June-July 2009, found that a clear magnetization low extends 500 m north from the Pika site. Acoustic signals, suggesting hydrothermal plumes, and 10 m-scale chimney-like topographic highs were detected within this low magnetization zone by a 120 kHz side-scan sonar and a 400 kHz multibeam echo sounder. In order to confirm the seafloor sources of the geophysical signals, seafloor observations were carried out using the deep-sea manned submersible Shinkai 6500 during the YK 10-10 cruise in August 2010. This discovered a new hydrothermal vent site (1255.30'N, 14338.89'E; at a depth of 2922 m), which we have named the Urashima site. This hydrothermal vent site covers an area of approximately 300 m300 m and consists of black and clear smoker chimneys, brownish-colored shimmering chimneys, and inactive chimneys. All of the fluids sampled from the Urashima and Pika sites have chlorinity greater than local ambient seawater, suggesting subseafloor phase separation or leaching from rocks in the hydrothermal reaction zone. End-member compositions of the Urashima and Pika fluids suggest that fluids from two different sources feed the two sites, even though they are located on the same knoll and separated by only 500 m. We demonstrate that investigations on hydrothermal vent sites located in close proximity to one another can provide important insights into subseafloor hydrothermal fluid flow, and also that, while such hydrothermal sites are difficult to detect by conventional plume survey methods, high-resolution underwater geophysical surveys provide an effective means.

Nakamura, Kentaro; Toki, Tomohiro; Mochizuki, Nobutatsu; Asada, Miho; Ishibashi, Jun-ichiro; Nogi, Yoshifumi; Yoshikawa, Shuro; Miyazaki, Jun-ichi; Okino, Kyoko

2013-04-01

100

The Sound Generated by Mid-Ocean Ridge Black Smoker Hydrothermal Vents  

E-print Network

The Sound Generated by Mid-Ocean Ridge Black Smoker Hydrothermal Vents Timothy J. Crone*, William S, Seattle, Washington, United States of America Hydrothermal flow through seafloor black smoker vents Generated by Mid-Ocean Ridge Black Smoker Hydrothermal Vents. PLoS ONE 1(1): e133. doi:10.1371/journal

Crone, Timothy J.

101

Hydrothermal microearthquake swarms beneath active vents at Middle Valley, northern Juan de Fuca Ridge  

E-print Network

Hydrothermal microearthquake swarms beneath active vents at Middle Valley, northern Juan de Fuca Dog vent field, a major hydrothermal area in Middle Valley with exit fluid temperatures near 270°C, Hydrothermal microearthquake swarms beneath active vents at Middle Valley, northern Juan de Fuca Ridge, J

Webb, Spahr C.

102

Bioaccumulation of Hg, Cu, and Zn in the Azores Triple Junction hydrothermal vent field food chains  

E-print Network

1 Bioaccumulation of Hg, Cu, and Zn in the Azores Triple Junction hydrothermal vent field food benthic invertebrates species (the key species) from the Mid Atlantic Ridge (MAR) hydrothermal vent fields. The samples were collected from three hydrothermal vent fields ­ Menez Gwen, 840 m; Lucky Strike, 1700 m

Paris-Sud XI, Université de

103

Tectonic//volcanic segmentation and controls on hydrothermal venting along Earth's fastest seafloor  

E-print Network

Tectonic//volcanic segmentation and controls on hydrothermal venting along Earth's fastest seafloor, as well as CTDO tow-yos, to determine detailed structural and volcanic controls on the hydrothermal vent was relatively high and fracture density was relatively low. These correlations suggest that hydrothermal venting

Bohnenstiehl, Delwayne

104

Protection mechanisms of the iron-plated armor of a deep-sea hydrothermal vent gastropod  

E-print Network

Protection mechanisms of the iron-plated armor of a deep-sea hydrothermal vent gastropod Haimin from the Kairei Indian hydrothermal vent field, which is unlike any other known natural or synthetic of a gastropod mollusc from a deep-sea hydrothermal vent [order Neomphalina (18), family Peltospiridae (19

Dao, Ming

105

Hydrothermal Vents Goal of the Lesson Introduce connection between ocean geology and biology,  

E-print Network

Hydrothermal Vents Goal of the Lesson ­ Introduce connection between ocean geology and biology, reinforce concepts taught in plate tectonics. Key Concepts · Hydrothermal vents occur because of plate tectonics · Hydrothermal vents support rich communities of animals · Introduce that the seafloor has many

Carrington, Emily

106

Mantle helium reveals Southern Ocean hydrothermal venting Gisela Winckler,1,2  

E-print Network

Click Here for Full Article Mantle helium reveals Southern Ocean hydrothermal venting Gisela; accepted 21 January 2010; published 2 March 2010. [1] Hydrothermal venting along the global midocean ridge of hydrothermal venting. We identify three complete ridge segments, a portion of a fourth segment and two isolated

Winckler, Gisela

107

The discovery of chemoautotrophic symbionts in the hydrothermal vent tubeworm Riftia pachyptila expanded our  

E-print Network

The discovery of chemoautotrophic symbionts in the hydrothermal vent tubeworm Riftia pachyptila at hydrothermal vents, hydrocarbon seeps and other chemically reduced deep-sea environments, exhibit a suite the symbiont's metabolic requirements, including the elimination of waste products. The hydrothermal vent

Girguis, Peter R.

108

Feeding biology of the shrimp Rimicaris exoculata at hydrothermal vents on the Mid-Atlantic Ridge  

Microsoft Academic Search

A newly described species of shrimp, Rimicaris exoculata Williams and Rona, 1986, dominates the megafaunal community at two hydrothermal vent sites on the Mid-Atlantic Ridge. Behavioral observations and gut-content analyses indicate, that these shrimp ingest large amounts of sulfide particles from black smoker chimneys. We found no evidence for chemoautotrophic endosymbionts in R. exoculata, based on analyses of morphology, stable

C. L. Dover; B. Fry; J. F. Grassle; S. Humphris; P. A. Rona

1988-01-01

109

Hydrothermal Vents at 5000m on the Mid-Cayman Rise: The Deepest and Hottest Hydrothermal Systems Yet Discovered!  

NASA Astrophysics Data System (ADS)

This contribution describes the geological setting of hydrothermal 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 hydrothermal 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 hydrothermal plumes (German et al., in 2009), we discovered two high-temperature hydrothermal 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 sites show contrasting styles of fluid venting, mineralisation, geological setting and host rock interaction. At 5000m-depth, the ultra-deep vent site forms the deepest hydrothermal system known. Venting 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 venting 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 vent fluids. A prominent axial volcanic ridge nearby indicates a robust magma supply to the northern MCR segment. Thus it is likely the ultra-deep vent site derives its thermal energy from magmatic sources, similar to those thought to underlie other slow-spreading ridge volcanic-hosted vent sites (e.g. Broken Spur: MAR). The shallower (2300m) MCR hydrothermal vent site hosts vigorous medium-temperature fluid discharge from sulphide chimneys at the summit of an 80m diameter sulphide mound. Exiting vent 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 vent site 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 hydrothermal system. The only detectable signature from this vent field is its low Eh plume. As a result, we believe that this style of venting has hitherto been overlooked, and thus its global significance for the cooling and alteration of slow-spread oceanic crust may be greatly underestimated.

Murton, B. J.; Connelly, D. P.; Copley, J. T.; Stansfield, K. L.; Tyler, P. A.; Cruise Jc044 Sceintific Party

2010-12-01

110

Microbial diversity of a sulfide black smoker in main endeavour hydrothermal vent field, Juan de Fuca Ridge  

Microsoft Academic Search

Submarine hydrothermal vents are among the least-understood habitats on Earth but have been the intense focus of research\\u000a in the past 30 years. An active hydrothermal sulfide chimney collected from the Dudley site in the Main Endeavour vent Field\\u000a (MEF) of Juan de Fuca Ridge was investigated using mineralogical and molecular approaches. Mineral analysis indicated that\\u000a the chimney was composed

Huaiyang Zhou; Jiangtao Li; Xiaotong Peng; Jun Meng; Fengping Wang; Yuncan Ai

2009-01-01

111

Evolutionary relationships among deep-sea mytilids (Bivalvia: Mytilidae) from hydrothermal vents and cold-water methane\\/sulfide seeps  

Microsoft Academic Search

A protein electrophoretic survey of mytilids inhabiting deep-sea hydrothermal vents and cold-water methane\\/sulfide seeps revealed electromorph patterns diagnostic of 10 distinct species. From hydrothermal vents located at sites on the Galpagos Rift, the Mid-Atlantic Ridge, and the Mariana Back Arc Basin, we detected four species of mytilids. Six additional species were detected from three cold-water seep sides in the Gulf

C. Craddock; W. R. Hoeh; R. G. Gustafson; R. A. Lutz; J. Hashimoto; R. J. Vrijenhoek

1995-01-01

112

Larval abundance and dispersal at deep-sea hydrothermal vents in the southern Mariana Trough  

NASA Astrophysics Data System (ADS)

Since the discovery of deep-sea hydrothermal vents 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 hydrothermal vents. Here, we will present results of an international, collaborative effort to study larval abundance and dispersal at vents 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 Vents (Volcanic) Unit sites in the U.S. Marianas Trench Marine National Monument. These vents 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 vent 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 Site. We will deploy a current meter near the Snail site (on-axis) for preliminary estimates of passive larval transport on the time scale of the cruise. The three study sites 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 vents that we will visit are as close as 25 km to known vents on the arc, yet 600 km south of the other known vents in the back-arc. These two tectonic settings create different habitat conditions and support vent communities with different species composition. Will we collect larvae of species that are commonly found at (generally shallower) vents on the Mariana arc? The larval studies will help address the question of how populations of vent-endemic species are connected at hydrothermal vents within the new Marine National Monument.

Beaulieu, S. E.; Watanabe, H.; Mills, S. W.; Pradillon, F.; Kojima, S.; Mullineaux, L. S.

2010-12-01

113

Mineralization of Alvinella polychaete tubes at hydrothermal vents  

PubMed Central

Alvinellid polychaete worms form multilayered organic tubes in the hottest and most rapidly growing areas of deep-sea hydrothermal vent 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 hydrothermal vents. 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 hydrothermal vent 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 hydrothermal vents to soft tissue preservation in sediments and hot springs. PMID:25556400

Georgieva, M N; Little, C T S; Ball, A D; Glover, A G

2015-01-01

114

Mineralization of Alvinella polychaete tubes at hydrothermal vents.  

PubMed

Alvinellid polychaete worms form multilayered organic tubes in the hottest and most rapidly growing areas of deep-sea hydrothermal vent 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 hydrothermal vents. 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 hydrothermal vent 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 hydrothermal vents to soft tissue preservation in sediments and hot springs. PMID:25556400

Georgieva, M N; Little, C T S; Ball, A D; Glover, A G

2015-03-01

115

What causes random earthquakes within a hydrothermal vent?  

NASA Astrophysics Data System (ADS)

The Trans-Atlantic Geotraverse (TAG) is the largest deep sea hydrothermal vent field found anywhere on the planet. Located on the Mid-Atlantic Ridge, a seafloor spreading center where new oceanic crust is being created, the TAG field consists of one active high-temperature mound, one low-temperature mound, and seven inactive mounds.

Schultz, Colin

2014-07-01

116

Metal concentrations in the tissues of the hydrothermal vent mussel Bathymodiolus: reflection of different metal sources.  

PubMed

Hydrothermal vent mussels of the genus Bathymodiolus are ideally positioned for the use of recording hydrothermal fluxes at the hydrothermal vent sites 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 hydrothermal fields between 15N and 9S at the Mid-Atlantic Ridge were determined and compared to the surrounding fluids and solid substrates in the habitats. Elements generally enriched in hydrothermal fluids, such as Fe, Cu, Zn, Pb and Cd, were significantly enriched in the gills and digestive glands of the hydrothermal 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 hydrothermal 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 site indicate a relation to the ?400C 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 sites 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

Koschinsky, Andrea; Kausch, Matteo; Borowski, Christian

2014-04-01

117

A deep sea Hydrothermal Vent Bio-sampler for large volume in-situ filtration of hydrothermal vent fluids  

NASA Technical Reports Server (NTRS)

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 hydrothermal vent off the northern coast of Iceland.

Behar, Alberto; Matthews, Jaret; Venkateswaran, Kasthuri; Bruckner, James; Basic, Goran; So, Edmond; Rivadeneyra, Cesar

2005-01-01

118

Investigations of a novel fauna from hydrothermal vents along the Arctic Mid-Ocean Ridge (AMOR) (Invited)  

NASA Astrophysics Data System (ADS)

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 hydrothermal vents. Deep-sea hydrothermal vents 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 hydrothermal vents 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 venting and wide areas with low-temperature seepage, located at 5-700 m, while the deeper Loki Castle vent 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 venting and barite chimneys. The Jan Mayen sites show low abundance of specialized hydrothermal vent fauna. Single groups have a few specialized representatives but groups otherwise common in hydrothermal vent areas are absent. Slightly more than 200 macrofaunal species have been identified from this vent 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 vent field contains a much more diverse vent 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 vents, but some gastropod species show a structured population difference between the sites. Our data indicate that there has been a migration of vent fauna into the Arctic Ocean from the Pacific Ocean rather than from the known vent sites further south in the Atlantic Ocean. The discovery and sampling of these new arctic vent fields provide unique data to further understand the migration of vent organisms and interactions between different deep sea chemosynthetic environments. Based on the high degree of local adaptation and specialization of fauna from the studied sites we propose the AMOR to be a new zoogeographical province for vent fauna.

Rapp, H.; Schander, C.; Halanych, K. M.; Levin, L. A.; Sweetman, A.; Tverberg, J.; Hoem, S.; Steen, I.; Thorseth, I. H.; Pedersen, R.

2010-12-01

119

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

PubMed Central

Since the first discovery of deep-sea hydrothermal vents along the Galpagos Rift in 1977, numerous vent sites 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 hydrothermal vents 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 hydrothermal vents hosting high-temperature black smokers up to 382.8C and diffuse venting. The chemosynthetic ecosystems hosted by these vents are dominated by a new yeti crab (Kiwa n. sp.), stalked barnacles, limpets, peltospiroid gastropods, anemones, and a predatory sea star. Taxa abundant in vent ecosystems in other oceans, including polychaete worms (Siboglinidae), bathymodiolid mussels, and alvinocaridid shrimps, are absent from the ESR vents. 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 vent taxa. Evidence from the distinctive fauna, the unique community structure, and multivariate analyses suggest that the Antarctic vent ecosystems represent a new vent biogeographic province. However, multivariate analyses of species present at the ESR and at other deep-sea hydrothermal vents globally indicate that vent biogeography is more complex than previously recognised. PMID:22235194

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

2012-01-01

120

The discovery of new deep-sea hydrothermal vent communities in the southern ocean and implications for biogeography.  

PubMed

Since the first discovery of deep-sea hydrothermal vents along the Galpagos Rift in 1977, numerous vent sites 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 hydrothermal vents 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 hydrothermal vents hosting high-temperature black smokers up to 382.8C and diffuse venting. The chemosynthetic ecosystems hosted by these vents are dominated by a new yeti crab (Kiwa n. sp.), stalked barnacles, limpets, peltospiroid gastropods, anemones, and a predatory sea star. Taxa abundant in vent ecosystems in other oceans, including polychaete worms (Siboglinidae), bathymodiolid mussels, and alvinocaridid shrimps, are absent from the ESR vents. 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 vent taxa. Evidence from the distinctive fauna, the unique community structure, and multivariate analyses suggest that the Antarctic vent ecosystems represent a new vent biogeographic province. However, multivariate analyses of species present at the ESR and at other deep-sea hydrothermal vents globally indicate that vent biogeography is more complex than previously recognised. PMID:22235194

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

2012-01-01

121

Life in hot springs and hydrothermal vents  

Microsoft Academic Search

Hot springs and hydrothermal systems occurring within volcanic areas are inhabited by hyperthermophilic microorganisms, some of which grow at temperatures up to 110 C. Hyperthermophiles grow anaerobically or aerobically by diverse metabolic types. Within the high temperature ecocystems, primary production is independent from solar energy.

Andreas H. Segerer; Sigfried Burggraf; Gerhard Fiala; Gertrud Huber; Robert Huber; Ursula Pley; Karl O. Stetter

1993-01-01

122

The Geological Setting of Hydrothermal Vents on the Ultra-slow Spreading Gakkel Ridge  

NASA Astrophysics Data System (ADS)

The Gakkel Ridge is the planet's slowest spreading and least explored mid-ocean ridge, extending through the Eurasian Basin of the Arctic Ocean from northern Greenland to the Laptev Sea. Systematic exploration of the Gakkel Ridge began in 1996 with the SCience ICe EXercises (SCICEX) program, which used U.S. Navy nuclear submarines operating beneath the Arctic ice canopy to map the surface and subsurface of the Gakkel Ridge. Among the SCICEX results were the first full-coverage bathymetry and sidescan maps of the axis and flanks of the Gakkel Ridge. In the summer of 2001, the Arctic Mid-Ocean Ridge Expedition (AMORE) conducted the first systematic petrological sampling of the Gakkel Ridge. AMORE also included a reconnaissance for hydrothermal plumes using Miniature Autonomous Plume Recorders (MAPRs) and a small number of CTD casts. The results from the SCICEX and AMORE expeditions demonstrate that there is significantly more volcanism and hydrothermal venting on the Gakkel Ridge than predicted by models for ultra-slow spreading ridges and that the distribution of volcanoes and hydrothermal vents differs from that reported for slow-spreading mid-ocean ridges such as the Mid-Atlantic Ridge. We have combined the sidescan and bathymetry data collected during the SCICEX mission with the hydrothermal findings of the AMORE survey to develop a model geological setting for hydrothermal vent sites on this ultra-slow spreading ridge. Unlike slow-spreading ridges where hydrothermal venting is frequently associated with fault-dominated regions, on the Gakkel Ridge most of the vent sites identified during the AMORE cruise are localized at volcanic centers that SCICEX data show to occur intermittently along the axial valley floor. One particularly strong hydrothermal plume was found to occur near a tectonized volcano located at 85E on the Gakkel Ridge, a site hypothesized to have erupted in 1999 on the basis of a teleseismically-detected earthquake swarm and high acoustic reflectivity. We hypothesize that the strong association of hydrothermal plumes and volcanic centers on the Gakkel Ridge is a function of the overall thermally cool character of this ultra-slow spreading ridge: while faults still provide the pathways for hydrothermal circulation, there is only enough heat to develop a convecting system available at volcanic centers.

Edmonds, H. N.; Edwards, M. H.; Kurras, G. J.; German, C. R.

2002-12-01

123

First hydrothermal active vent discovered on the Galapagos Microplate  

NASA Astrophysics Data System (ADS)

The Galapagos Microplate (GM) lies on the western Gaplapagos Spreading Center (GSC), representing one of the classic Ridge-Ridge-Ridge (R-R-R) plate boundaries of the Nazca, Cocos, and Pacific plates. The presence of the 'black smoke' and hydrothermal vent community were firstly confirmed on the GSC. Lots of hydrothermal fields were discovered on the center and eastern GSC, while the western GSC has not been well investigated. During 17th Oct. to 9th Nov. 2009, the 3rd leg of Chinese DY115-21 cruise with R/V Dayangyihao has been launched along 2N-5S near equatorial East Pacific Rise (EPR). Two new hydrothermal fields were confirmed. One is named 'Precious Stone Mountain', which is the first hydrothermal field on the GM. The other is found at 101.47W, 0.84S EPR. The 'Precious Stone Mountain' hydrothermal field (at 101.49W, 1.22N) is located at an off-axial seamount on the southern GM boundary, with a depth from 1,450 to 1,700m. Hydrothermal fluids emitting from the fissures and hydrothermal fauna were captured by deep-tow video. Few mineral clasts of pyrite and chalcopyrite were separated from one sediment sample, but no sulfide chimney was found yet. Hydrothermal fauna such as alive mussels, crabs, shrimps, tubeworms, giant clams, as well as rock samples were collected by TV-Grab. The study of the seafloor classification with Simrad EM120 multi-beam echosounder has been conducted on the 'Precious Stone Mountain' hydrothermal field. The result indicates that seafloor materials around the hydrothermal field can be characterized into three types, such as the fresh lava, hydrothermal sediment, and altered rock.

Tao, C.; Li, H.; Wu, G.; Su, X.; Zhang, G.; Chinese DY115-21 Leg 3 Scientific Party

2011-12-01

124

Hydrogen-limited growth of hyperthermophilic methanogens at deep-sea hydrothermal vents  

E-print Network

Hydrogen-limited growth of hyperthermophilic methanogens at deep-sea hydrothermal vents Helene C, and approved June 29, 2012 (received for review April 21, 2012) Microbial productivity at hydrothermal vents at vents are lacking. We used a combina- tion of cultivation, molecular, and geochemical tools to verify

Holden, James F.

125

Introduction The deep-sea hydrothermal vent communities were discovered in  

E-print Network

312 Introduction The deep-sea hydrothermal vent communities were discovered in 1977 and immediately. The physiological functioning of hydrothermal vent species, especially R. pachyptila, was studied intensively also been found. Early on in vent research it was apparent that the giant tubeworm, Riftia pachyptila

Girguis, Peter R.

126

On the rise of turbulent plumes: Quantitative effects of variable entrainment for submarine hydrothermal vents, terrestrial  

E-print Network

hydrothermal vents, terrestrial and extra terrestrial explosive volcanism G. Carazzo,1 E. Kaminski,1 and S: Quantitative effects of variable entrainment for submarine hydrothermal vents, terrestrial and extra terrestrial, paleo-Martian, and Venusian conditions and by submarine hydrothermal activity at mid-ocean ridges

Kaminski, Edouard

127

Biogenic iron oxyhydroxide formation at mid-ocean ridge hydrothermal vents: Juan de Fuca Ridge  

E-print Network

Biogenic iron oxyhydroxide formation at mid-ocean ridge hydrothermal vents: Juan de Fuca Ridge kg?1 (German and von Damm, 2004). As vented hydrothermal fluids mix with cold, oxygenated deep in mid-ocean ridge (MOR) hydrothermal end-member fluids at concentrations ranging from 0.007 to 25 mmol

128

Hydrothermal venting in magma deserts: The ultraslow-spreading Gakkel and Southwest Indian Ridges  

E-print Network

Hydrothermal venting in magma deserts: The ultraslow- spreading Gakkel and Southwest Indian Ridges of hydrothermal venting, but the validity of this relation at slow and ultraslow ridges is unproved. Here we, Massachusetts 02138, USA (langmuir@eps.harvard.edu) [1] Detailed hydrothermal surveys over ridges with spreading

Langmuir, Charles H.

129

Characterizing Microbial Community and Geochemical Dynamics at Hydrothermal Vents Using Osmotically Driven Continuous Fluid  

E-print Network

Characterizing Microbial Community and Geochemical Dynamics at Hydrothermal Vents Using Osmotically.5 year laboratory study as well as the results of two field deployments at deep-sea hydrothermal vents data reveal marked changes in microbial composition co-occurring with changes in hydrothermal fluid

Girguis, Peter R.

130

Evolutionary and biogeographical patterns of barnacles from deep-sea hydrothermal vents.  

PubMed

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 hydrothermal vent barnacles represent an excellent model for testing biogeographical hypotheses regarding the origin, dispersal and diversity of modern vent fauna. Here, we characterize the global genetic diversity of vent 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-site associated DNA sequencing on individuals from each species. Phylogenetic inferences and topology hypothesis tests indicate that vent barnacles have colonized deep-sea hydrothermal vents at least twice in history. Consistent with preliminary estimates, we find a likely radiation of barnacles in vent ecosystems during the Cenozoic. Our analyses suggest that the western Pacific was the place of origin of the major vent 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 vent 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

Herrera, Santiago; Watanabe, Hiromi; Shank, Timothy M

2015-02-01

131

Oxidation of polymetal sulfides by chemolithoautotrophic bacteria from deep?sea hydrothermal vents  

Microsoft Academic Search

Aerobic mesophilic sulfur?oxidizing bacteria were tested for their ability to utilize a variety of natural and commercial polymetal sulfides as energy sources at near neutral pH. Substantial fixation of CO2 by natural microbial populations covering polymetal sulfide deposits was observed in in situ experiments conducted from DSV ALVIN at the Mid?Atlantic Ridge hydrothermal vent sites at a depth of 3600

Carolyn Eberhard; Carl O. Wirsen; Holger W. Jannasch

1995-01-01

132

Vertebrate nutrition in a deep-sea hydrothermal vent ecosystem: Fatty acid and stable isotope evidence  

NASA Astrophysics Data System (ADS)

The hydrothermal vent zoarcid fish Thermarces cerberus is a top predator that inhabits deep-sea hydrothermal vents on the East Pacific Rise (EPR). Bacterial chemoautotrophy at these sites 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 vent 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 vent 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 vent taxa.

Pond, D. W.; Fallick, A. E.; Stevens, C. J.; Morrison, D. J.; Dixon, D. R.

2008-12-01

133

Subseafloor Microbial Life in Venting Fluids from the Mid Cayman Rise Hydrothermal System  

NASA Astrophysics Data System (ADS)

In hard rock seafloor environments, fluids emanating from hydrothermal vents 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 venting fluids collected from two newly discovered deep-sea hydrothermal vents along the ultra-slow spreading Mid-Cayman Rise (MCR). Fluids for geochemical and microbial analysis were collected from the Von Damm and Piccard vent 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 sites, 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 venting fluids, distinct from background populations, and are consistent with previous enumerations of microbial cells in venting 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 site 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 vent fluids, a basalt-hosted black smoker site located at ~4950 m with a maximum temperature of 403 C. However, hyperthermophilic and thermophilic heterotrophs of the genus Thermococcus were isolated from Piccard vent fluids, but not Von Damm. These obligate anaerobes, growing optimally at 55-90 C, are ubiquitous at hydrothermal systems and serve as a readily cultivable indicator organism of subseafloor populations. Finally, molecular analysis of vent 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.

Huber, J. A.; Reveillaud, J.; Reddington, E.; McDermott, J. M.; Sylva, S. P.; Breier, J. A.; German, C. R.; Seewald, J.

2012-12-01

134

Metatranscriptomics reveal differences in in situ energy and nitrogen metabolism among hydrothermal vent snail symbionts  

E-print Network

Despite the ubiquity of chemoautotrophic symbioses at hydrothermal vents, our understanding of the influence of environmental chemistry on symbiont metabolism is limited. Transcriptomic analyses are useful for linking ...

Sanders, J. G.

135

Geochemistry of hydrothermal vent fluids from the northern Juan De Fuca Ridge  

E-print Network

The presence of aqueous organic compounds derived from sedimentary organic matter has the potential to influence a range of chemical processes in hydrothermal vent environments. For example, hydrothermal alteration experiments ...

Cruse, Anna M. (Anna Marie)

2003-01-01

136

Reproductive traits of pioneer gastropod species colonizing deep-see hydrothermal vents after an eruption  

E-print Network

The colonization dynamics and life histories of pioneer species are vital components in understanding the early succession of nascent hydrothermal vents. The reproductive ecology of pioneer species at deep-sea hydrothermal ...

Bayer, Skylar (Skylar Rae)

2011-01-01

137

Influence of environmental conditions on early development of the hydrothermal vent polychaete Alvinella pompejana.  

PubMed

Dispersal and colonisation processes at deep-sea vents are still not fully understood, essentially because early life stages of vent species remain unknown. The polychaete worm Alvinella pompejana forms colonies on chimney walls at East Pacific Rise vent sites where the temperature can frequently exceed 20 degrees C. In vitro studies in pressure vessels showed that the early embryos tolerate temperatures in a lower range (10-14 degrees C), suggesting that they would have to escape the colony to develop. Pressure vessels offer the advantage that each parameter can be independently controlled, but they do not simulate the more complex and dynamic conditions naturally encountered at vent sites. Accordingly, in addition to incubations in pressure vessels, we incubated embryos directly at a vent site, in different habitats along a gradient of hydrothermal influence. Embryos incubated on an adult A. pompejana colony where temperature and H(2)S concentrations were relatively high showed a very low survival rate and did not develop, whereas embryos incubated in a Riftia pachyptila clump environment with a lower hydrothermal signature, or at the base of the chimney where the influence of the hydrothermal activity was very weak, survived well and developed. Although the average temperature recorded in the A. pompejana colony was within the range tolerated by embryos (13 degrees C), frequent peaks above 20 degrees C were recorded. Estimated sulphide concentration at this site reached 200 mumol l(-1). Punctuated exposure to both high temperature and elevated sulphide levels probably explain the low survival of embryos within the A. pompejana colony. The in situ experiments further support the idea that embryos require conditions with moderate hydrothermal influence not generally found within an adult colony. However, as much more benign physicochemical conditions can be found within a few tens of cm of adult colonies, embryos do not necessarily have to leave their vent of origin to develop. Further analyses are needed to pinpoint the specific factors that affect the survival and development of embryos at vents. PMID:15802678

Pradillon, Florence; Le Bris, Nadine; Shillito, Bruce; Young, Craig M; Gaill, Franoise

2005-04-01

138

Reactivity landscape of pyruvate under simulated hydrothermal vent conditions.  

PubMed

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 hydrothermal vent 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 hydrothermal systems on the early earth. We report here that pyruvate reacts readily in the presence of transition metal sulfide minerals under simulated hydrothermal vent 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

Novikov, Yehor; Copley, Shelley D

2013-08-13

139

Reactivity landscape of pyruvate under simulated hydrothermal vent conditions  

PubMed Central

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 hydrothermal vent 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):13371340], so it is plausible that pyruvate was formed in hydrothermal systems on the early earth. We report here that pyruvate reacts readily in the presence of transition metal sulfide minerals under simulated hydrothermal vent fluids at more moderate temperatures (25110 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

Novikov, Yehor; Copley, Shelley D.

2013-01-01

140

Cameras on the NEPTUNE Canada seafloor observatory: Towards monitoring hydrothermal vent ecosystem dynamics  

NASA Astrophysics Data System (ADS)

Hydrothermal vent environments are among the most dynamic benthic habitats in the ocean. The relative roles of physical and biological factors in shaping vent community structure remain unclear. Undersea cabled observatories offer the power and bandwidth required for high-resolution, time-series study of the dynamics of vent communities and the physico-chemical forces that influence them. The NEPTUNE Canada cabled instrument array at the Endeavour hydrothermal vents provides a unique laboratory for researchers to conduct long-term, integrated studies of hydrothermal vent ecosystem dynamics in relation to environmental variability. Beginning in September-October 2010, NEPTUNE Canada (NC) will be deploying a multi-disciplinary suite of instruments on the Endeavour Segment of the Juan de Fuca Ridge. Two camera and sensor systems will be used to study ecosystem dynamics in relation to hydrothermal discharge. These studies will make use of new experimental protocols for time-series observations that we have been developing since 2008 at other observatory sites connected to the VENUS and NC networks. These protocols include sampling design, camera calibration (i.e. structure, position, light, settings) and image analysis methodologies (see communication by Aron et al.). The camera systems to be deployed in the Main Endeavour vent field include a Sidus high definition video camera (2010) and the TEMPO-mini system (2011), designed by IFREMER (France). Real-time data from three sensors (O2, dissolved Fe, temperature) integrated with the TEMPO-mini system will enhance interpretation of imagery. For the first year of observations, a suite of internally recording temperature probes will be strategically placed in the field of view of the Sidus camera. These installations aim at monitoring variations in vent community structure and dynamics (species composition and abundances, interactions within and among species) in response to changes in environmental conditions at different temporal scales. High-resolution time-series studies also provide a mean of studying population dynamics, biological rhythms, organism growth and faunal succession. In addition to programmed time-series monitoring, the NC infrastructure will also permit manual and automated modification of observational protocols in response to natural events. This will enhance our ability to document potentially critical but short-lived environmental forces affecting vent communities.

Robert, K.; Matabos, M.; Sarrazin, J.; Sarradin, P.; Lee, R. W.; Juniper, K.

2010-12-01

141

Dynamic drivers of a shallow-water hydrothermal vent ecogeochemical system (Milos, Eastern Mediterranean)  

NASA Astrophysics Data System (ADS)

Shallow-water hydrothermal vents 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 vent 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 hydrothermal tracers (e.g. Fe2+, FeSaq, Mn2+) on sediment cores taken along a transect in hydrothermally affected sediments indicate three different areas: the central vent 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 hydrothermal 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 vent center showed substantial temporal variability in temperature (32 to 46 C ) and total sulfide (488 to 1329 M) 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 hydrothermally influenced sediments Diversity and metagenomic analyses on sediments and biofilm collected along a transect from the center to the outer rim of the vent 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 site is also a relevant model to investigate the link between ecological and abiotic dynamics in such instable hydrothermal environments. Our results provide evidence for the importance of transient geodynamic and hydrodynamic events in the dynamics and distribution of chemoautotrophic communities in the hydrothermally influenced sediments of Paleochori Bay.

Ycel, Mustafa; Sievert, Stefan; Giovanelli, Donato; Foustoukos, Dionysis; DeForce, Emelia; Thomas, Franois; Vetriani, Constantino; Le Bris, Nadine

2014-05-01

142

Chemistry of hydrothermal solutions from Pele's Vents, Loihi Seamount, Hawaii  

SciTech Connect

Hydrothermal fluids were sampled from Pele's Vents on the summit of Loihi Seamount, an intraplate, hotspot volcano, on four occasions from February 1987 to September 1990. The warm ([le]31C) vent 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 vents 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 vent fluids with ambient seawater. These juvenile inputs likely reflect the shallow, hotspot setting of this hydrothermal 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.

Sedwick, P.N.; McMurtry, G.M. (Univ. of Hawaii, Honolulu (United States)); Macdougall, J.D. (Scripps Institution of Oceanography, La Jolla, CA (United States))

1992-10-01

143

Are midwater shrimp trapped in the craters of submarine volcanoes by hydrothermal venting?  

NASA Astrophysics Data System (ADS)

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. Hydrothermal venting 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 vents, while other individuals lay immobile on sediments. The shrimp fauna consisted of 3 mesopelagic species that had no prior record of benthic or vent 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 vent environment (immobile individuals) or whether they are potentially opportunistic vent residents (active individuals). Given the abundance of submarine arc volcanoes worldwide, this phenomenon suggests that volcanic arcs could be important interaction sites between oceanic midwater and vent communities.

Wishner, Karen F.; Graff, Jason R.; Martin, Joel W.; Carey, S.; Sigurdsson, H.; Seibel, B. A.

2005-08-01

144

S-33 constraints on the seawater sulfate contribution in modern seafloor hydrothermal vent sulfides  

NASA Astrophysics Data System (ADS)

Sulfide sulfur in mid-oceanic ridge hydrothermal vents 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 vent fluid H 2S 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 SF 6 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 vent H 2S collected from four active seafloor hydrothermal vent sites, East Pacific Rise (EPR) 9-10N, 13N, and 21S and Mid-Atlantic Ridge (MAR) 37N 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 vent sulfides are derived from leaching from basaltic sulfide and only 11 to 27% from seawater-derived sulfate. Pyrite from EPR 13N and marcasite from MAR 37N 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 hydrothermal vent sulfides are characterized by low ? 33S values compared with biogenic sulfides, suggesting little or no contribution of sulfide from microbial sulfate reduction into hydrothermal 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 hydrothermal sulfur cycles.

Ono, Shuhei; Shanks, Wayne C.; Rouxel, Olivier J.; Rumble, Douglas

2007-03-01

145

S-33 constraints on the seawater sulfate contribution in modern seafloor hydrothermal vent sulfides  

USGS Publications Warehouse

Sulfide sulfur in mid-oceanic ridge hydrothermal vents 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 vent 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 vent H2S collected from four active seafloor hydrothermal vent sites, 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 vent 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 hydrothermal vent sulfides are characterized by low ??33S values compared with biogenic sulfides, suggesting little or no contribution of sulfide from microbial sulfate reduction into hydrothermal 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 hydrothermal sulfur cycles. ?? 2006 Elsevier Inc. All rights reserved.

Ono, S.; Shanks, W. C., III; Rouxel, O.J.; Rumble, D.

2007-01-01

146

Influence of sea-floor spreading on the global hydrothermal vent fauna  

Microsoft Academic Search

ONE remarkable discovery of recent decades is the presence of hundreds of unusual species, including fourteen new families, at hydrothermal vents. These animals, unknown from other habitats, live in extreme chemical and thermal conditions around vents on spreading centres of the mid-ocean ridges and back-arc basins. Chemosynthesis provides an in situ energy source for the thriving vent fauna. This habitat

Verena Tunnicliffe; C. Mary R. Fowler

1996-01-01

147

Sulphur isotopic compositions of deep-sea hydrothermal vent animals  

NASA Technical Reports Server (NTRS)

The S-34/S-32 ratios of tissues from vestimentiferan worms, brachyuran crabs, and giant clams living around deep hydrothermal vents 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 vent 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 vent 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.

Fry, B.; Gest, H.; Hayes, J. M.

1983-01-01

148

Nitrogen geochemistry as a tracer of fluid flow in a hydrothermal vent complex in the Karoo Basin, South Africa  

E-print Network

Nitrogen geochemistry as a tracer of fluid flow in a hydrothermal vent complex in the Karoo Basin and hydrothermal vent complexes (HVC) in the Karoo Basin in South Africa. The HVC formed during phreatic eruptions. Bulk-rock N isotope data for rocks from inside and outside the hydrothermal vent com- plex fall

Svensen, Henrik

149

O-Proteobacterial diversity from a deep-sea hydrothermal vent on the Mid-Atlantic Ridge  

E-print Network

O-Proteobacterial diversity from a deep-sea hydrothermal vent on the Mid-Atlantic Ridge Erwan Corre with an in situ growth chamber deployed for 5 days on a Mid-Atlantic Ridge hydrothermal vent (23³22PN, 44³57PW Science B.V. All rights reserved. Keywords: Hydrothermal vent; Bacterial diversity; Phylogenetic analysis

Reysenbach, Anna-Louise

150

Marine culturable yeasts in deep-sea hydrothermal vents:1 Species richness and association with fauna2  

E-print Network

Marine culturable yeasts in deep-sea hydrothermal vents:1 Species richness and association - Hydrothermal vents - Fauna - 26S rRNA gene ­ FISH11 12 13 Running title: Culturable yeasts from hydrothermal vents14 15 16 17 18 19 20 21 22 23 24 25 hal-00609796,version1

Paris-Sud XI, Université de

151

Biogeographic relationships among deep-sea hydrothermal vent faunas at global scale  

Microsoft Academic Search

The discovery of deep-sea hydrothermal vent fauna, kilometres deep in the oceans, is a great achievement of 20th-century marine biology. The deep-sea hydrothermal food web does not directly depend on the sun's energy. Vent communities rely primarily on trophic associations between chemoautotrophic bacteria and consumers. A small number of endemic taxa are adapted to the inhospitable vent environments that are

C. Bachraty; P. Legendre; D. Desbruyres

2009-01-01

152

A new species of the shrimp genus Chorocaris (Decapoda: Caridea: Alvinocarididae) from hydrothermal vents in the eastern Pacific Ocean  

Microsoft Academic Search

Chorocaris paulexa, new species, the first member of the genus Chorocaris Martin & Hessler, 1990 reported from the eastern Pacific, is de scribed based primarily on two specimens, one of which is ovigerous, collected by the DSV Alvin at the Homer hydrothermal (black smoker) vent site (17S) on the southern East Pacific Rise (SEPR). Seven additional (non-type) speci mens from

Joel W. Martin; Timothy M. Shank

2005-01-01

153

Simulated Mars Rover Mission to Hydrothermal Vents, Ka'u Desert, Hawai'i  

NASA Astrophysics Data System (ADS)

Observations and measurements were made in the field and samples returned for laboratory study from the Ka'u Desert, Hawai'i. The site includes recent lava flows and flanking older flows, wind-blown and variably altered ash deposits, and alteration associated with sulfurous volcanic vents. The site is an analogue for the type being proposed for the NASA Mars Mobile Geobiology Explorer Mission. Experiments and observations included tripod-based color stereo imaging, thermal imaging, and reflectance spectrometry to map topography, thermal properties, and mineralogy associated with flow and ash-deposit alteration stages and hydrothermal deposits. Laboratory analyses include mineralogy, elemental compositions, and biological analysis of returned samples for ground truth and for comparison to what can be learned from field observations. Integrated studies include comparison of VIS-IR spectra obtained on the ground and observed lithologic endmembers to remotely sensed data and spectral endmembers (Deal et al., this Conf.), development of a topographic model from stereo imaging, alteration of basalts and relationships between ash deposits and basalts, including formation of duricrusts, thermal imaging and development of a thermal model, and characterization of extant and fossilized biological activity associated with sulfurous hydrothermal vents. Analyses to examine active biology at the hydrothermal vents include DNA amplification and identification using PCR (polymerase chain reaction) methods and FISH (fluorescence in-situ hybridization). Morphological evidence of entombment of microbes will be sought in mineralized crusts associated with the hydrothermal deposits. Video documentation of field work coupled with results of field observations and laboratory analyses will be used to better understand and define the essential measurements to make during future Mars missions, with implications for procedures and protocols for eventual sample returns.

Jolliff, B. L.; Arvidson, R. E.; Doty, A. M.; Davies, N.; de St. Maurice, A.; Griggs, L. E.; Gross, M. E.; Ishida, C. C.; Izsak, G. M.; Deal, K. S.; Snider, N. O.

2002-12-01

154

Detoxification mechanisms in shrimp: comparative approach between hydrothermal vent fields and estuarine environments.  

PubMed

Hydrothermal vents are extreme deep-sea habitats that, due to their singular features, still intrigue scientific communities. Swift growth rates and profuse biomass of biological communities can be observed, despite of their inherently unstable physical-chemical and toxic conditions, indicating that organisms inhabiting this environment must be well adapted to these inhospitable conditions. The caridean shrimp, Chorocaris chacei, Mirocaris fortunata and Rimicaris exoculata, together with bathymodiolid mussels, dominate the vent fauna along the Mid-Atlantic Ridge (MAR). Crustacean species are widely used as biological indicators of environmental alterations, since they play a key ecological role as planktivorous grazers, epibenthic scavengers or as prey species. The biological consequences of the hydrothermal metal-rich environment in shrimp species are still largely unknown. Therefore, the aim of this study was the determination of the metal levels (Ag, Cd, Cu, Fe, Mn and Zn), metallothioneins (MT) and lipid peroxidation (LPO) in shrimp species collected in Rainbow, Lucky Strike and Menez-Gwen vent sites, in order to evaluate their different adaptation strategies toward metals when compared with two common coastal shrimp species (Palaemon elegans and Palaemonetes varians) from a fairly unpolluted estuarine system in south Portugal (Ria Formosa). Results show significant differences in metal concentrations, MT levels and lipid peroxidation between vent and coastal shrimp and also between shrimp species from the same site. This indicates that biochemical responses in both vent and coastal shrimp are affected not only by the environmental characteristics but also by inter-specific differences. Nevertheless, these responses apparently grant a successful adaptation for the survival in a metal-extreme environment. PMID:18405963

Gonzalez-Rey, Maria; Serafim, Angela; Company, Rui; Gomes, Tnia; Bebianno, Maria Joo

2008-07-01

155

The influence of vent fluid chemistry on trophic structure at two deep-sea hydrothermal vent fields on the Mid-Cayman Rise  

NASA Astrophysics Data System (ADS)

The two known deep-sea hydrothermal vent 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 vent fields, Piccard (with active venting from Beebe Vents, Beebe Woods and Beebe Sea), at 4980 m is basalt hosted. The shallower vent field, Von Damm, at 2300 m appears to have an ultramafic influence. The Von Damm vent field can be separated into two sites: The Spire and The Tubeworm Field. The dominant vent 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 vent 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 vent fields, they are much more abundant at one site than the other. In this study we have examined the bulk carbon, nitrogen and sulfur isotope composition of microbes and fauna at each vent field. With these data we have deduced the trophic structure of the communities and the influence of vent fluid chemistry. From stable isotope data and end-member vent 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 vent fluids and processes in the sub-surface that alter the vent 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 vent sites. Part of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with National Aeronautics and Space Administration (NASA).

Bennett, Sarah; Van Dover, Cindy; Coleman, Max

2014-05-01

156

Neutrophilic Fe-Oxidizing Bacteria Are Abundant at the Loihi Seamount Hydrothermal Vents and Play a Major Role in Fe Oxide Deposition  

Microsoft Academic Search

A number of hydrothermal vent sites exist on the summit of the Loihi Seamount, a shield volcano that is part of the Hawaiian archipelago. The vents are 1,100 to 1,325 m below the surface and range in temperature from slightly above ambient (10C) to high temperature (167C). The vent fluid is characterized by high concen- trations of CO2 (up to

David Emerson; Craig L. Moyer

2002-01-01

157

Magnetic Structure of Backarc Spreading Axis with Hydrothermal Vents; the Southern Mariana Trough  

NASA Astrophysics Data System (ADS)

Seafloor hydrothermal systems are important in relation to global heat and chemical fluxes as well as habitat of microbial communities. The substantial variation of hydrothermal 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 hydrothermal systems from sea-surface data because the small scale of hydrothermal 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 hydrothermal areas. Near-bottom magnetic surveys can provide direct information on the magnetization of the shallower oceanic crust, implying hydrothermal alteration both in active and fossil vent sites. Near-bottom three component magnetic measurements on submersible Shinkai 6500 were carried out at hydrothermal 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 hydrothermal 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 hydrothermal vents (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 hydrothermal site (Snail Site) at different altitude, 2m and 30m. Transect 3 (T3) also crosses a large on-axis volcanic mound on which another hydrothermal site (Yamanaka Site) 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 hydrothermal field recognized from high-resolution bathymetry (Yoshikawa et al., 2012). A similar reduction of magnetization above hydrothermal fields was also reported in basalt-hosted sites 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 Site compared to results of the 2D methods.

Fujii, M.; Okino, K.; Mochizuki, N.; Honsho, C.; Szitkar, F.; Dyment, J.; Nakamura, K.

2012-12-01

158

When did decapods invade hydrothermal vents? Clues from the Western Pacific and Indian Oceans.  

PubMed

Hydrothermal vents 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 hydrothermal vents discovered to date. Contrary to the hypothesis that these species are remnants of relic fauna, increasing evidence supports the notion that hydrothermal vent 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 hydrothermal vents throughout the Western Pacific and Indian Oceans. A partitioned mix-model phylogenomic analysis of mitochondrial DNA produced a consistent phylogenetic topology of these vent-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 hydrothermal vent 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 vent 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 hydrothermal vent species and their distribution in the Western Pacific-Indian Ocean Region. PMID:23002089

Yang, Jin-Shu; Lu, Bo; Chen, Dian-Fu; Yu, Yan-Qin; Yang, Fan; Nagasawa, Hiromichi; Tsuchida, Shinji; Fujiwara, Yoshihiro; Yang, Wei-Jun

2013-02-01

159

Microbial community structure of hydrothermal deposits from geochemically different vent fields along the Mid-Atlantic Ridge  

SciTech Connect

To evaluate the effects of local fluid geochemistry on microbial communities associated with active hydrothermal vent deposits, we examined the archaeal and bacterial communities of 12 samples collected from two very different vent 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) vent 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 vent 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 vent fluids at the ultramafic-influenced Rainbow vent field support the prevalence of methanogens and other hydrogen-oxidizing thermophiles at this site. These results demonstrate that biogeographical patterns of hydrothermal vent microorganisms are shaped in part by large scale geological and geochemical processes.

Flores, Gilberto E [Portland State University; Campbell, James H [ORNL; Kirshtein, Julie D [United States Geological Survey, Reston, VA; Meneghin, Jennifer [Portland State University; Podar, Mircea [ORNL; Steinberg, Joshua [Oregon Episcopal School, Portland, OR; Seewald, Jeffrey S [Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA; Tivey, Margaret Kingston [Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA; Voytek, Mary A [United States Geological Survey & National Aeronautics and Space Administration; Reysenbach, Anna-Louise [Portland State University; Yang, Zamin Koo [ORNL

2011-01-01

160

Microbial community structure of hydrothermal deposits from geochemically different vent fields along the Mid-Atlantic Ridge  

USGS Publications Warehouse

To evaluate the effects of local fluid geochemistry on microbial communities associated with active hydrothermal vent deposits, we examined the archaeal and bacterial communities of 12 samples collected from two very different vent fields: the basalt-hosted Lucky Strike (3717'N, 3216.3'W, depth 1600-1750m) and the ultramafic-hosted Rainbow (3613'N, 3354.1'W, depth 2270-2330m) vent 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 vent 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 vent fluids at the ultramafic-influenced Rainbow vent field support the prevalence of methanogens and other hydrogen-oxidizing thermophiles at this site. These results demonstrate that biogeographical patterns of hydrothermal vent microorganisms are shaped in part by large scale geological and geochemical processes.

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

2011-01-01

161

Phylogenetic diversity and functional gene patterns of sulfur-oxidizing subseafloor Epsilonproteobacteria in diffuse hydrothermal vent fluids  

PubMed Central

Microorganisms throughout the dark ocean use reduced sulfur compounds for chemolithoautotrophy. In many deep-sea hydrothermal vents, 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 vent endemic Epsilonproteobacteria was examined in six low-temperature diffuse vents 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 vent sites, but not in background seawater. Although Sulfurovum-like soxB genes were detected in all fluid samples, the RNA profiles were nearly identical among the vents and suggest that Sulfurimonas-like species are the primary Epsilonproteobacteria responsible for actively oxidizing sulfur via the Sox pathway at each vent. Community patterns of subseafloor Epsilonproteobacteria 16S rRNA genes were best matched to methane concentrations in vent fluids, as well as individual vent 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 vent location and chemistry. PMID:23847608

Akerman, Nancy H.; Butterfield, David A.; Huber, Julie A.

2013-01-01

162

A comparison of bivalve ( Calyptogena magnifica) growth at two deep-sea hydrothermal vents in the eastern Pacific  

NASA Astrophysics Data System (ADS)

Analyses of specimens of a common deep-sea hydrothermal vent bivalve, Calyptogena magnifica, from two hydrothermal vent sites 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 hydrothermal vent communities. Ontogenetic growth curves for C. magnifica specimens at both hydrothermal sites 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-vent habitat. These data provide additional evidence that biological processes at submarine hydrothermal vents 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 vent fluids. In a 20 cm distance spanning 10 cm into a bivalve assemblage atop an active vent 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 vent sites, 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 vent sites.

Lutz, Richard A.; Fritz, Lowell W.; Cerrato, Robert M.

1988-10-01

163

Bacterial and Archaeal Community Dynamics at CO2-RICH Shallow-Sea Hydrothermal Vents (panarea, Italy)  

NASA Astrophysics Data System (ADS)

Shallow marine hydrothermal vents 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 hydrothermal vents off Panarea Island, in Sicily. We investigated two contrasting hydrothermal environments: Hot Lake, a depression filled with hydrothermal fluids diffusing gradually out of the seafloor, with temperatures ranging from 40 to 70C, and Blackpoint, a site with vigorous venting of hydrothermal gasses and fluids with temperatures as high as 135C. 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 site, 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. 70C. In contrast to Hot Lake, Archaea dominated sediments at the much hotter site at Blackpoint. Here, novel methylated H-shaped archaeal tetraethers, with multiple sugars as head groups, were the most abundant membrane lipids. Reports on these lipids in cultures are very limited, but their abundant occurrence at elevated temperatures suggests an important role in membrane homeostastis in thermophilic Archaea. Stable carbon isotope values of -35 to -10 for bacterial fatty acids and archaeal ether lipids indicate that microbial communities at both Hot Lake and Blackpoint are primarily autotrophic (?13CTOC ~ -20, ?13CDIC ~ +3). We will discuss potential carbon fixation pathways in light of known isotopic fractionations for lipids, and accompanying metagenome investigations, which suggests the reductive tricaboxylic acid cycle as important carbon fixation pathway at Hot Lake.

Schubotz, F.; Huang, C.; Meyerdierks, A.; Amend, J.; Price, R. E.; Amann, R.; Hinrichs, K.; Summons, R. E.

2013-12-01

164

Characterization of the Molecular Diversity of Rio Tinto Using a Novel Hydrothermal Vent Biosampler  

NASA Astrophysics Data System (ADS)

A Hydrothermal Vent Biosampler to collect "pristine" biological samples from complex ecosystems was used to collect samples from the highly acidic Rio Tinto waters. DNA was isolated and universal bacterial, eukaryotic and archaeal primers were used.

Behar, A. E.; Stam, C. N.; Scalzi, G.; Behncke, S.; Gmez, F.; Venkateswaran, K.

2010-04-01

165

Linking geology, fluid chemistry, and microbial activity of basalt- and ultramafic-hosted deep-sea hydrothermal vent environments.  

PubMed

Hydrothermal fluids passing through basaltic rocks along mid-ocean ridges are known to be enriched in sulfide, while those circulating through ultramafic mantle rocks are typically elevated in hydrogen. Therefore, it has been estimated that the maximum energy in basalt-hosted systems is available through sulfide oxidation and in ultramafic-hosted systems through hydrogen oxidation. Furthermore, thermodynamic models suggest that the greatest biomass potential arises from sulfide oxidation in basalt-hosted and from hydrogen oxidation in ultramafic-hosted systems. We tested these predictions by measuring biological sulfide and hydrogen removal and subsequent autotrophic CO2 fixation in chemically distinct hydrothermal fluids from basalt-hosted and ultramafic-hosted vents. We found a large potential of microbial hydrogen oxidation in naturally hydrogen-rich (ultramafic-hosted) but also in naturally hydrogen-poor (basalt-hosted) hydrothermal fluids. Moreover, hydrogen oxidation-based primary production proved to be highly attractive under our incubation conditions regardless whether hydrothermal fluids from ultramafic-hosted or basalt-hosted sites were used. Site-specific hydrogen and sulfide availability alone did not appear to determine whether hydrogen or sulfide oxidation provides the energy for primary production by the free-living microbes in the tested hydrothermal fluids. This suggests that more complex features (e.g., a combination of oxygen, temperature, biological interactions) may play a role for determining which energy source is preferably used in chemically distinct hydrothermal vent biotopes. PMID:23647923

Perner, M; Hansen, M; Seifert, R; Strauss, H; Koschinsky, A; Petersen, S

2013-07-01

166

Bacterial Group II Introns in a Deep-Sea Hydrothermal Vent Environment  

NSDL National Science Digital Library

This Applied and Environmental Microbiology journal article (PDF) reports the discovery of group II introns in a bacterial mat sample collected from a deep-sea hydrothermal vent near 9N 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 hydrothermal vents.

167

Genetic Diversity of Archaea in Deep-Sea Hydrothermal Vent Environments  

Microsoft Academic Search

Molecular phylogenetic analysis of naturally occurring archaeal communities in deep-sea hydrothermal vent 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 hydrothermal vent environments showed a great genetic diversity, and most members of these populations appeared to be uncultivated

Ken Takai; Koki Horikoshi

168

Spatial Differences in East Scotia Ridge Hydrothermal Vent Food Webs: Influences of Chemistry, Microbiology and Predation on Trophodynamics  

PubMed Central

The hydrothermal vents 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. Vent fluid and macroconsumer samples were collected at three vent sites (E2, E9N and E9S) at distances of tens of metres to hundreds of kilometres apart with contrasting vent fluid chemistries to describe trophic interactions and identify potential carbon fixation pathways using stable isotopes. ?13C of dissolved inorganic carbon from vent fluids ranged from ?4.6 to 0.8 at E2 and from ?4.4 to 1.5 at E9. The lowest macroconsumer ?13C was observed in peltospiroid gastropods (?30.0 to ?31.1) and indicated carbon fixation via the Calvin-Benson-Bassham (CBB) cycle by endosymbiotic gamma-Proteobacteria. Highest ?13C occurred in Kiwa sp. (?19.0 to ?10.5), similar to that of the epibionts sampled from their ventral setae. Kiwa sp. ?13C differed among sites, 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. Site differences in carbon fixation pathways were traced into higher trophic levels e.g. a stichasterid asteroid that predates on Kiwa sp. Sponges and anemones at the periphery of E2 assimilated a proportion of epipelagic photosynthetic primary production but this was not observed at E9N. Differences in the ?13C and ?34S values of vent macroconsumers between E2 and E9 sites suggest the relative contributions of photosynthetic and chemoautotrophic carbon fixation (rTCA v CBB) entering the hydrothermal vent food webs vary between the sites. PMID:23762393

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.

2013-01-01

169

Spatial differences in East scotia ridge hydrothermal vent food webs: influences of chemistry, microbiology and predation on trophodynamics.  

PubMed

The hydrothermal vents 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. Vent fluid and macroconsumer samples were collected at three vent sites (E2, E9N and E9S) at distances of tens of metres to hundreds of kilometres apart with contrasting vent fluid chemistries to describe trophic interactions and identify potential carbon fixation pathways using stable isotopes. ?(13)C of dissolved inorganic carbon from vent fluids ranged from -4.6 to 0.8 at E2 and from -4.4 to 1.5 at E9. The lowest macroconsumer ?(13)C 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 ?(13)C occurred in Kiwa sp. (-19.0 to -10.5), similar to that of the epibionts sampled from their ventral setae. Kiwa sp. ?(13)C differed among sites, 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. Site 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 ?(13)C and ?(34)S values of vent macroconsumers between E2 and E9 sites suggest the relative contributions of photosynthetic and chemoautotrophic carbon fixation (rTCA v CBB) entering the hydrothermal vent food webs vary between the sites. PMID:23762393

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

2013-01-01

170

Relationships between lava types, seafloor morphology, and the occurrence of hydrothermal venting in the ASHES vent field of Axial Volcano. [Axial Seamount Hydrothermal Emission Study  

SciTech Connect

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 vent field in the caldera. Locations for over 2,000 photographs in and near the vent field were determined using a seafloor transponder network. Then each photograph was described utilizing a classification system which provides detailed information concerning lava type, hydrothermal 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 venting. The most vigorous venting is concentrated in an approximately 80 m {times} 80 m area where there are several high-temperature vents including some which are producing high-temperature vapor-phase fluids derived from a boiling hydrothermal system. Lava types within the ASHES vent 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 hydrothermal venting 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 venting appears to be related also to the spatial distribution of lava types in the vent field and their contrasting permeabilities. Other structural trends of faults and fissures within the field also influence the location of individual events.

Hammond, S.R. (NOAA, Newport, OR (United States))

1990-08-10

171

In Situ Measurements of Chemical Distributions in a Deep-Sea Hydrothermal Vent Field  

Microsoft Academic Search

Large changes in the concentration of sulfide around a hydrothermal vent in the Galapagos Rift provide direct evidence for the consumption of sulfide by the organisms of the vent community. These changes were detected with a new chemical analyzer capable of measuring silicate, sulfide, oxygen, and temperature on the sea floor at depths of 2500 meters. More than 10,000 measurements

Kenneth S. Johnson; Carl L. Beehler; Carole M. Sakamoto-Arnold; James J. Childress

1986-01-01

172

Surface-Generated Mesoscale Eddies Transport Deep-Sea Products from Hydrothermal Vents  

Microsoft Academic Search

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 hydrothermal vent efflux and of vent larvae away from the northern East Pacific Rise. Transport by these deep-reaching

Diane K. Adams; Dennis J. McGillicuddy; Luis Zamudio; Andreas M. Thurnherr; Xinfeng Liang; Olivier Rouxel; Christopher R. German; Lauren S. Mullineaux

2011-01-01

173

Ammonificins A and B, Hydroxyethylamine Chroman Derivatives from a Cultured Marine Hydrothermal Vent Bacterium, ThermoWibrio ammonificans  

E-print Network

), were isolated from the marine hydrothermal vent bacterium ThermoVibrio ammonificans. The molecular report of secondary metabolites from the marine hydrothermal vent bacterium T. ammonificans. The oceansAmmonificins A and B, Hydroxyethylamine Chroman Derivatives from a Cultured Marine Hydrothermal

174

Deep-sea hydrothermal vent Epsilonproteobacteria encode a conserved and widespread nitrate reduction pathway (Nap).  

PubMed

Despite the frequent isolation of nitrate-respiring Epsilonproteobacteria from deep-sea hydrothermal vents, 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 hydrothermal vents. Furthermore, we have shown that the napA gene is expressed in pure cultures of vent Epsilonproteobacteria and it is highly conserved in microbial communities collected from deep-sea vents characterized by different temperature and redox regimes. The diversity of nitrate-reducing Epsilonproteobacteria was found to be higher in moderate temperature, diffuse flow vents 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 vent Epsilonproteobacteria may represent an adaptation of these organisms to the low nitrate concentrations typically found in vent fluids. Taken together, our findings indicate that nitrate reduction is widespread in vent Epsilonproteobacteria and provide insight on alternative energy metabolism in vent microorganisms. The occurrence of the nap cluster in vent, commensal and pathogenic Epsilonproteobacteria suggests that the ability of these bacteria to respire nitrate is important in habitats as different as the deep-sea vents and the human body. PMID:24430487

Vetriani, Costantino; Voordeckers, James W; Crespo-Medina, Melitza; O'Brien, Charles E; Giovannelli, Donato; Lutz, Richard A

2014-07-01

175

Carbon13 Depletion in a Hydrothermal Vent Mussel: Suggestion of a Chemosynthetic Food Source  

Microsoft Academic Search

Tissues of a mytilid mussel from the Clambake I hydrothermal vent in the Galapagos Rift zone are strikingly depleted in carbon-13 relative to the tissues of other marine organisms. The stable carbon isotope composition of this mussel suggests that chemoautotrophic bacteria present in the hydrothermal waters are a major food source for filter-feeding organisms in this abyssal environment.

Greg H. Rau; John I. Hedges

1979-01-01

176

Lipid Biomarkers and Molecular Carbon Isotopes for Elucidating Carbon Cycling Pathways in Hydrothermal Vents  

NASA Astrophysics Data System (ADS)

Increasing molecular evidence suggests that hydrothermal vents in mid-ocean ridges harbor large populations of free-living bacteria, particularly the epsilon Proteobacteria. However, pathways for carbon metabolism by these bacteria are poorly known. We are addressing this question by analyzing the lipid biomarkers and their isotope signatures in environments where the epsilon Proteobacteria are likely predominant. Solid materials were collected from hydrothermal vents in the East Pacific Rise and at the Guaymas Basin in the Gulf of California. Fatty acids extracted from these samples are dominated by 16:0 (27-41%), 18:0 (16-48%), 18:1 (11-42%), 16:1 (7-12%), and 14:0 (5-28%). In addition, 15:0 and anteiso-15:0 are significantly present (2-3%) in samples from the Guaymas Basin. The isotopic compositions of these fatty acids range from -15.0\\permil to -33.1\\permil with the most positive values occurring only in monounsaturated fatty acids (16:1 and 18:1). We are currently unable to assign these biomarkers to any of the epsilon Proteobacteria because biomarkers are poorly known for these organisms isolated from the vents. However, no polyunsaturated fatty acids were detected in these samples, which are consistent with the absence of vent animals at the sampling sites. Signature biomarkers of 20:1 and cy21:0, which are characteristic of the thermophilic chemolithoautotrophs such as Aquificales, are also absent in these samples. These results imply that the deeply branched Aquificales species do not constitute the major microbial community in these vent environments. The large range of molecular isotopic compositions suggests that these lipids are synthesized from various carbon sources with different isotopic compositions or through different biosynthetic pathways, or both. We are currently measuring the isotopic compositions of the total organic carbon in the bulk samples and will determine the fractionations between lipid biomarkers and the total organic carbon. Molecular DNA data from these vent environments indicate that the reversed TCA cycle may be used for CO2 fixation by the epsilon Proteobacteria for chemolithoautotrophic growth. Isotopic fractionation patterns between lipid biomarkers and the bulk organic carbon can provide independent information on this unique biosynthetic pathway.

Zhang, C. L.; Dai, J.; Campbell, B.; Cary, C.; Sun, M.

2003-12-01

177

Sulfide Ameliorates Metal Toxicity for Deep-Sea Hydrothermal Vent Archaea  

PubMed Central

The chemical stress factors for microbial life at deep-sea hydrothermal vents include high concentrations of heavy metals and sulfide. Three hyperthermophilic vent 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 hydrothermal vent archaea to tolerate otherwise toxic metal concentrations in their natural environment. PMID:15066859

Edgcomb, Virginia P.; Molyneaux, Stephen J.; Saito, Mak A.; Lloyd, Karen; Ber, Simone; Wirsen, Carl O.; Atkins, Michael S.; Teske, Andreas

2004-01-01

178

The microbiology of deep-sea hydrothermal vent plumes: ecological and biogeographic linkages to seafloor and water column habitats  

PubMed Central

Hydrothermal plumes are an important yet understudied component of deep-sea vent microbial ecosystems. The significance of plume microbial processes can be appreciated from three perspectives: (1) mediation of plume biogeochemistry, (2) dispersal of seafloor hydrothermal vent microbes between vents sites, (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 vent 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 vent sites. Finally, we put forward three pressing questions for the future of deep-sea hydrothermal plume research and consider interactions between vents and oceans on global scales. PMID:23720658

Dick, Gregory J.; Anantharaman, Karthik; Baker, Brett J.; Li, Meng; Reed, Daniel C.; Sheik, Cody S.

2013-01-01

179

Biotic interactions at hydrothermal vents: Recruitment inhibition by the mussel Bathymodiolus thermophilus  

NASA Astrophysics Data System (ADS)

The structure and dynamics of marine communities are regulated in part by variation in recruitment. As in other ecosystems, recruitment at deep-sea hydrothermal vents is controlled by the interplay of propagule supply and behavior, gradients in physical-chemical conditions, and biotic interactions during pre- and post-settlement periods. Recent research along the East Pacific Rise indicates that inhibition of recently settled larvae by mobile predators (mainly limpets) influences patterns of recruitment and subsequent community succession. We conducted a manipulative experiment at the same sites (2510 m water depth) to test whether high-density assemblages of the mussel Bathymodiolus thermophilus also inhibit recruitment. In a preliminary study, recruitment of vent invertebrates within the faunal zone dominated by B. thermophilus was strikingly different at two sites, East Wall and Worm Hole. East Wall had high densities of mussels but very low total recruitment. In contrast, Worm Hole had few mussels but high recruitment. Using the submersible Alvin, we transplanted a large number of mussels from East Wall to Worm Hole and quantified recruitment on basalt blocks placed in three treatments: (1) naturally high densities of mussels at East Wall; (2) naturally low densities of mussels at Worm Hole; and (3) high densities of transplanted mussels at Worm Hole. After 11 months, a total of 24 taxa had recruited to the basalt blocks. Recruitment was 44-60% lower in the transplanted high-density mussel patch at Worm Hole and the natural high-density patch at East Wall than within the natural low-density patch at Worm Hole. Biotic processes that may have caused the pattern of recruitment observed included predation of larvae via water filtration by mussels, larval avoidance of superior competitors, interference competition, and enhanced predation by species within the mussel-bed community. Our results indicate that biotic interactions affecting recruitment must be understood to explain patterns of invertebrate community organization and dynamics at hydrothermal vents.

Lenihan, H. S.; Mills, S. W.; Mullineaux, L. S.; Peterson, C. H.; Fisher, C. R.; Micheli, F.

2008-12-01

180

Growth and Phylogenetic Properties of Novel Bacteria Belonging to the Epsilon Subdivision of the Proteobacteria Enriched from Alvinella pompejana and Deep-Sea Hydrothermal Vents  

PubMed Central

Recent molecular characterizations of microbial communities from deep-sea hydrothermal sites indicate the predominance of bacteria belonging to the epsilon subdivision of Proteobacteria (epsilon Proteobacteria). Here, we report the first enrichments and characterizations of four epsilon Proteobacteria that are directly associated with Alvinella pompejana, a deep sea hydrothermal vent polychete, or with hydrothermal vent chimney samples. These novel bacteria were moderately thermophilic sulfur-reducing heterotrophs growing on formate as the energy and carbon source. In addition, two of them (Am-H and Ex-18.2) could grow on sulfur lithoautrotrophically using hydrogen as the electron donor. Optimal growth temperatures of the bacteria ranged from 41 to 45C. Phylogenetic analysis of the small-subunit ribosomal gene of the two heterotrophic bacteria demonstrated 95% similarity to Sulfurospirillum arcachonense, an epsilon Proteobacteria isolated from an oxidized marine surface sediment. The autotrophic bacteria grouped within a deeply branching clade of the epsilon Proteobacteria, to date composed only of uncultured bacteria detected in a sample from a hydrothermal vent along the mid-Atlantic ridge. A molecular survey of various hydrothermal vent environments demonstrated the presence of two of these bacteria (Am-N and Am-H) in more than one geographic location and habitat. These results suggest that certain epsilon Proteobacteria likely fill important niches in the environmental habitats of deep-sea hydrothermal vents, where they contribute to overall carbon and sulfur cycling at moderate thermophilic temperatures. PMID:11571157

Campbell, Barbara J.; Jeanthon, Christian; Kostka, Joel E.; Luther, George W.; Cary, S. Craig

2001-01-01

181

Growth and phylogenetic properties of novel bacteria belonging to the epsilon subdivision of the Proteobacteria enriched from Alvinella pompejana and deep-sea hydrothermal vents.  

PubMed

Recent molecular characterizations of microbial communities from deep-sea hydrothermal sites indicate the predominance of bacteria belonging to the epsilon subdivision of Proteobacteria (epsilon Proteobacteria). Here, we report the first enrichments and characterizations of four epsilon Proteobacteria that are directly associated with Alvinella pompejana, a deep sea hydrothermal vent polychete, or with hydrothermal vent chimney samples. These novel bacteria were moderately thermophilic sulfur-reducing heterotrophs growing on formate as the energy and carbon source. In addition, two of them (Am-H and Ex-18.2) could grow on sulfur lithoautrotrophically using hydrogen as the electron donor. Optimal growth temperatures of the bacteria ranged from 41 to 45 degrees C. Phylogenetic analysis of the small-subunit ribosomal gene of the two heterotrophic bacteria demonstrated 95% similarity to Sulfurospirillum arcachonense, an epsilon Proteobacteria isolated from an oxidized marine surface sediment. The autotrophic bacteria grouped within a deeply branching clade of the epsilon Proteobacteria, to date composed only of uncultured bacteria detected in a sample from a hydrothermal vent along the mid-Atlantic ridge. A molecular survey of various hydrothermal vent environments demonstrated the presence of two of these bacteria (Am-N and Am-H) in more than one geographic location and habitat. These results suggest that certain epsilon Proteobacteria likely fill important niches in the environmental habitats of deep-sea hydrothermal vents, where they contribute to overall carbon and sulfur cycling at moderate thermophilic temperatures. PMID:11571157

Campbell, B J; Jeanthon, C; Kostka, J E; Luther, G W; Cary, S C

2001-10-01

182

Complete Genome Sequence of Thermococcus sp. Strain 4557, a Hyperthermophilic Archaeon Isolated from a Deep-Sea Hydrothermal Vent Area  

PubMed Central

Thermococcus sp. strain 4557 is a hyperthermophilic anaerobic archaeon isolated from the deep-sea hydrothermal vent Guaymas Basin site in the Gulf of California at a depth of 2,000 m. Here, we present the complete genome sequence of Thermococcus sp. 4557, which consists of a single circular chromosome of 2,011,320 bp with a G+C content of 56.08%. PMID:21914870

Wang, Xingna; Gao, Zhaoming; Xu, Xun; Ruan, Lingwei

2011-01-01

183

Submarine fissure eruptions and hydrothermal vents on the southern Juan de Fuca Ridge: preliminary observations from the submersible Alvin.  

USGS Publications Warehouse

The submersible Alvin was used to investigate 3 active hydrothermal discharge sites along the S Juan de Fuca Ridge in September 1984. The hydrothermal 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 hydrothermal vents coincide with the main eruptive vents along the cleft. Each hydrothermal zone has multiple discharge sites 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 hydrothermal fluids have the highest chlorinity of any reported to date.-Authors

Normark, W.R.

1986-01-01

184

On the origin of biochemistry at an alkaline hydrothermal vent.  

PubMed

A model for the origin of biochemistry at an alkaline hydrothermal vent has been developed that focuses on the acetyl-CoA (Wood-Ljungdahl) pathway of CO2 fixation and central intermediary metabolism leading to the synthesis of the constituents of purines and pyrimidines. The idea that acetogenesis and methanogenesis were the ancestral forms of energy metabolism among the first free-living eubacteria and archaebacteria, respectively, stands in the foreground. The synthesis of formyl pterins, which are essential intermediates of the Wood-Ljungdahl pathway and purine biosynthesis, is found to confront early metabolic systems with steep bioenergetic demands that would appear to link some, but not all, steps of CO2 reduction to geochemical processes in or on the Earth's crust. Inorganically catalysed prebiotic analogues of the core biochemical reactions involved in pterin-dependent methyl synthesis of the modern acetyl-CoA pathway are considered. The following compounds appear as probable candidates for central involvement in prebiotic chemistry: metal sulphides, formate, carbon monoxide, methyl sulphide, acetate, formyl phosphate, carboxy phosphate, carbamate, carbamoyl phosphate, acetyl thioesters, acetyl phosphate, possibly carbonyl sulphide and eventually pterins. Carbon might have entered early metabolism via reactions hardly different from those in the modern Wood-Ljungdahl pathway, the pyruvate synthase reaction and the incomplete reverse citric acid cycle. The key energy-rich intermediates were perhaps acetyl thioesters, with acetyl phosphate possibly serving as the universal metabolic energy currency prior to the origin of genes. Nitrogen might have entered metabolism as geochemical NH3 via two routes: the synthesis of carbamoyl phosphate and reductive transaminations of alpha-keto acids. Together with intermediates of methyl synthesis, these two routes of nitrogen assimilation would directly supply all intermediates of modern purine and pyrimidine biosynthesis. Thermodynamic considerations related to formyl pterin synthesis suggest that the ability to harness a naturally pre-existing proton gradient at the vent-ocean interface via an ATPase is older than the ability to generate a proton gradient with chemistry that is specified by genes. PMID:17255002

Martin, William; Russell, Michael J

2007-10-29

185

Microdistribution of faunal assemblages at deep-sea hydrothermal vents in the Southern Ocean.  

PubMed

Chemosynthetic primary production by microbes supports abundant faunal assemblages at deep-sea hydrothermal vents, with zonation of invertebrate species typically occurring along physico-chemical gradients. Recently discovered vent fields on the East Scotia Ridge (ESR) in the Southern Ocean represent a new province of vent 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 hydrothermal activity in a vent 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 hydrothermal 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 vent sources and peak temperatures. Assemblages closest to vent 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 vent fauna in this new biogeographic province. An increase in ?(34)S values of primary consumers with distance from vent sources, and variation in their ?(13)C values also indicate possible zonation of nutritional modes of the vent fauna. By using ROV videography to obtain a high-resolution representation of a vent 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 vents. PMID:23144754

Marsh, Leigh; Copley, Jonathan T; Huvenne, Veerle A I; Linse, Katrin; Reid, William D K; Rogers, Alex D; Sweeting, Christopher J; Tyler, Paul A

2012-01-01

186

Microdistribution of Faunal Assemblages at Deep-Sea Hydrothermal Vents in the Southern Ocean  

PubMed Central

Chemosynthetic primary production by microbes supports abundant faunal assemblages at deep-sea hydrothermal vents, with zonation of invertebrate species typically occurring along physico-chemical gradients. Recently discovered vent fields on the East Scotia Ridge (ESR) in the Southern Ocean represent a new province of vent 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 hydrothermal activity in a vent 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 hydrothermal 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 vent sources and peak temperatures. Assemblages closest to vent 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 vent fauna in this new biogeographic province. An increase in ?34S values of primary consumers with distance from vent sources, and variation in their ?13C values also indicate possible zonation of nutritional modes of the vent fauna. By using ROV videography to obtain a high-resolution representation of a vent 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 vents. PMID:23144754

Marsh, Leigh; Copley, Jonathan T.; Huvenne, Veerle A. I.; Linse, Katrin; Reid, William D. K.; Rogers, Alex D.; Sweeting, Christopher J.; Tyler, Paul A.

2012-01-01

187

Cemented mounds and hydrothermal sediments on the detachment surface at Kane Megamullion: A new manifestation of hydrothermal venting  

NASA Astrophysics Data System (ADS)

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 hydrothermal venting 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. Hydrothermal effects on the detachment surface include (1) cemented mounds of igneous rock and chalk debris containing hydrothermal 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 hydrothermal fluids discharged through the detachment hanging wall near the active fault trace. Hydrothermal 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 vents, but they also precipitated from low-temperature fluids venting from the exposed footwall through overlying chalks. Observed natural disturbance and abnormally thin hydrogenous Fe-Mn crusts on some contorted, hydrothermal Fe-Mn-rich chalks on 2.7 Ma crust suggest diffuse venting 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 venting through fractured detachment footwalls may continue for several million years off-axis.

Tucholke, Brian E.; Humphris, Susan E.; Dick, Henry J. B.

2013-09-01

188

Genetic diversity of archaea in deep-sea hydrothermal vent environments.  

PubMed Central

Molecular phylogenetic analysis of naturally occurring archaeal communities in deep-sea hydrothermal vent 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 hydrothermal vent 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 hydrothermal vents 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 hydrothermal vent environments. These findings expand our view of the genetic diversity of archaea in deep-sea hydrothermal vent environments and of the phylogenetic organization of archaea. PMID:10430559

Takai, K; Horikoshi, K

1999-01-01

189

Larvae from afar colonize deep-sea hydrothermal vents after a catastrophic eruption  

PubMed Central

The planktonic larval stage is a critical component of life history in marine benthic species because it confers the ability to disperse, potentially connecting remote populations and leading to colonization of new sites. Larval-mediated connectivity is particularly intriguing in deep-sea hydrothermal vent communities, where the habitat is patchy, transient, and often separated by tens or hundreds of kilometers. A recent catastrophic eruption at vents near 950?N on the East Pacific Rise created a natural clearance experiment and provided an opportunity to study larval supply in the absence of local source populations. Previous field observations have suggested that established vent populations may retain larvae and be largely self-sustaining. If this hypothesis is correct, the removal of local populations should result in a dramatic change in the flux, and possibly species composition, of settling larvae. Fortuitously, monitoring of larval supply and colonization at the site had been established before the eruption and resumed shortly afterward. We detected a striking change in species composition of larvae and colonists after the eruption, most notably the appearance of the gastropod Ctenopelta porifera, an immigrant from possibly more than 300 km away, and the disappearance of a suite of species that formerly had been prominent. This switch demonstrates that larval supply can change markedly after removal of local source populations, enabling recolonization via immigrants from distant sites with different species composition. Population connectivity at this site appears to be temporally variable, depending not only on stochasticity in larval supply, but also on the presence of resident populations. PMID:20385811

Mullineaux, Lauren S.; Adams, Diane K.; Mills, Susan W.; Beaulieu, Stace E.

2010-01-01

190

ENERGY METABOLISM PATHWAYS OF HYDROTHERMAL VENT ANIMALS: ADAPTATIONS TO A FOOD-RICH AND SULFIDE-RICH DEEP-SEA ENVIRONMENT  

Microsoft Academic Search

The activities of enzymes of the major pathways of energy metabolism (glycol ysis, the citric acid cycle, and the electron transport system) were measured in tissues of animals from the deep-sea hydrothermal vent site at 21 °N latitude. Enzymic activities of related shallow-living marine animals were assayed for comparison. Vent species studied were the large pogonophoran tube worm, Riftia pachypti!a,

STEVEN C. HAND; GEORGE N. SOMERO

191

Mercury accumulation in hydrothermal vent mollusks from the southern Tonga Arc, southwestern Pacific Ocean.  

PubMed

We provide the mercury (Hg) and monomethylmercury (MMHg) levels of the plume water, sulfide ore, sediment, and mollusks located at the hydrothermal vent 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 hydrothermal fluids and (2) to examine the distribution of Hg and MMHg levels in hydrothermal 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 hydrothermal 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 vent field sediment. In addition, Hg concentrations in the mollusks were much higher (10-100 times) than in other hydrothermal vent 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 hydrothermal vent fields of the Tonga Arc and subsequent bioaccumulation are substantial, but not for MMHg. PMID:25748345

Lee, Seyong; Kim, Se-Joo; Ju, Se-Jong; Pak, Sang-Joon; Son, Seung-Kyu; Yang, Jisook; Han, Seunghee

2015-05-01

192

Zinc stable isotopes in seafloor hydrothermal vent fluids and chimneys  

Microsoft Academic Search

Many of the heaviest and lightest natural zinc (Zn) isotope ratios have been discovered in hydrothermal ore deposits. However, the processes responsible for fractionating Zn isotopes in hydrothermal systems are poorly understood. In order to better assess the total range of Zn isotopes in hydrothermal systems and to understand the factors which are responsible for this isotopic fractionation, we have

Seth G. John; Olivier J. Rouxel; Paul R. Craddock; Alison M. Engwall; Edward A. Boyle

2008-01-01

193

Microbial anaerobic methane cycling in the subseafloor at the Von Damm hydrothermal vent field, Mid-Cayman Rise  

NASA Astrophysics Data System (ADS)

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 hydrothermal vents (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 site is hosted in a distinct geologic setting with different thermal and chemical regimes. The Von Damm site is a particularly interesting location to examine chemolithoautotrophic subseafloor microbial communities due to the abundant hydrogen, methane, and organic compounds in the venting 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 hydrothermal fluids venting at the Von Damm site. 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 vents. 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 sites, 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 vent sites 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 venting fluids will reveal the genomic repertoire, evolutionary relationships, and adaptations of these unique methane-cycling anaerobic archaea in the subseafloor at the Von Damm hydrothermal vent field.

Huber, J. A.; Reveillaud, J. C.; Stepanauskas, R.; McDermott, J. M.; Sylva, S. P.; Seewald, J.

2013-12-01

194

Temporal change in megafauna at the Rose Garden hydrothermal vent (Galapagos Rift; eastern tropical Pacific)  

NASA Astrophysics Data System (ADS)

Hydrothermal vent communities must undergo substantial temporal change because of their dynamic physical milieu. This was verified in March 1985, when the Rose Garden hydrothermal vent on the Galapagos Rift was revisited after 5 1/4 years' absence. Comparison of photographs from the two visits revealed considerable faunal change. Among the hosts to chemoautotrophic bacteria, vestimentiferans were reduced from dominance to very low numbers. The mytilid was now extremely abundant and dominated vent openings. Vesicomyids also were more abundant. In general, vent-field suspension feeders had declined; anemones were distinctly less abundant, and siphonophores and enteropneusts were virtually absent. The decline of serpulids was likely, but less obvious. Of the mobile scavengers and carnivores, both galatheids and whelks were distincly more common. These community changes appear to result from both continuing recruitment and changes in the physical milieu. While the growth of some populations could have resulted from expanding opportunities, the population of at least one, the vesicomyid, had not achieved carrying capacity in 1979, and this could have pertained to others as well. The decrease of vestimentiferans may have been caused by declining vent-water flux, a process that would favor mytilids, or more complete vent-water filtration by the mytilids themselves. The same factors also could explain the reduction of vent-field filter feeders. These observations suggest that early stages in the cycle of Galapagos-type vent communities are likely to be dominated by vestimentiferans, but that bivalves will replace them with time.

Hessler, Robert R.; Smithey, William M.; Boudrias, Michel A.; Keller, Clifford H.; Lutz, Richard A.; Childress, James J.

1988-10-01

195

The potential for photosynthesis in hydrothermal vents: a new avenue for life in the Universe?  

E-print Network

We perform a quantitative assessment for the potential for photosynthesis in hydrothermal vents in the deep ocean. The photosynthetically active radiation in this case is from geothermal origin: the infrared thermal radiation emitted by hot water, at temperatures ranging from 473 up to 673 K. We find that at these temperatures the photosynthetic potential is rather low in these ecosystems for most known species. However, species which a very high efficiency in the use of light and which could use infrared photons till 1300nm, could achieve good rates of photosynthesis in hydrothermal vents. These organisms might also thrive in deep hydrothermal vents in other planetary bodies, such as one of the more astrobiologically promising Jupiter satellites: Europa.

Perez, Noel; Martin, Osmel; Leiva-Mora, Michel

2013-01-01

196

Patterns in Global Hydrothermal  

E-print Network

) High-T vents High = hydrothermal discharge Low = active or inactive discharge sites B. Davy, GNS NZ #12Patterns in Global Hydrothermal Activity noaa ocean exploration Presenter: Edward T. Baker #12;First vents discovered in the S Atl. First hi-T vents discovered on ultra-slow ridge Eruption discovered

197

Evidence of sub-vent biosphere: enzymatic activities in 308 C deep-sea hydrothermal systems at Suiyo seamount, IzuBonin Arc, Western Pacific Ocean  

Microsoft Academic Search

A high-temperature deep-sea hydrothermal system related to dacitic arc-volcanism was drilled using a tethered, submarine rock-drill system as a part of the Archaean Park Project. The benthic multi-coring system (BMS) employed allowed for direct sampling of microorganisms, rocks and fluids beneath hydrothermal vents. The samples examined in this study were from sites APSK 05 and APSK 07 on the Suiyo

Yoshinori Takano; Yae Edazawa; Kensei Kobayashi; Tetsuro Urabe; Katsumi Marumo

2005-01-01

198

NOAA VENTS Program  

NSDL National Science Digital Library

Research program investigating impacts of submarine volcanoes and hydrothermal venting on the global ocean. Research focuses on acoustic monitoring of earthquake and volcano activity, vent chemistry, and vent fluid transport. Research sites located in northeastern Pacific, western Pacific, eastern Pacific and northern Atlantic and include Mariana Arc, Axial Volcano, Gorda Ridge, and East Pacific Rise.

199

Isolation of Tellurite and Selenite-Resistant Bacteria from Hydrothermal Vents of the Juan de Fuca Ridge in the Pacific Ocean  

Microsoft Academic Search

Deep-ocean hydrothermal-vent environments are rich in heavy metals and metalloids and present excellent sites 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 hydrothermal vents, bacterial films, and sulfide-rich rocks. Growth of these isolates in media containing K2TeO3 or Na2SeO3 resulted in

Christopher Rathgeber; Natalia Yurkova; Erko Stackebrandt; J. Thomas Beatty; Vladimir Yurkov

2002-01-01

200

Biogeography and Evolution of Hydrothermal-Vent Fauna in the Eastern Pacific Ocean  

Microsoft Academic Search

The biogeography and evolutionary history of animals that live at hydrothermal vents are connected intimately to the spreading history of mid-ocean ridges. Extensive collections from two active ridge systems in the eastern Pacific Ocean provide an opportunity to examine the regional dispersion of vent-limited organisms. The degrees to which these habitat-limited species from disjunct areas are related gives preliminary information

Verena Tunnicliffe

1988-01-01

201

Diversity of deep-sea hydrothermal vent Archaea from Loihi Seamount, Hawaii  

Microsoft Academic Search

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 hydrothermal vent ecosystem located at Peles Vents on the summit of Loihi Seamount, Hawaii. These SSU rDNAs were amplified from extracted microbial mat

Craig L. Moyer; James M. Tiedje; Fred C. Dobbs; David M. Karl

1998-01-01

202

Dissolved free amino acids in hydrothermal vent habitats of the Guaymas Basin  

NASA Astrophysics Data System (ADS)

Total dissolved free amino acid (DFAA) concentrations and molecular compositions were determined in high-temperature smoker fluids (exit temperatures 152-319C) and interstitial waters of a sediment-covered hydrothermal vent system located in the southern Guaymas Basin, Gulf of California. DFAAs were not detected (? 1 nM) in the hot vent fluids, a result which probably reflects the instability of these compounds when exposed to the extreme high temperatures and pressures characteristic of hydrothermal fluids. Ammonium is the principal end-product of this thermal catalytic diagenesis. Hydrothermal vent and non-vent control sediments had DFAA concentrations ranging from 5-445 and 10-28 ?M, respectively. The DFAA concentrations in both habitats were highest in the near-surface region (0-4 cm) and decreased at greater depths. The depth-dependent concentration gradients for hydrothermally impacted sediments were steeper than for the control samples and covaried with total microbial biomass. The molecular composition of the hydrothermally impacted samples included most common protein amino acids in addition to ?-aminoglutaric acid. Glutamate, glycine, serine, and alanine were major constituents of the DFAA pool.

Haberstroh, P. R.; Karl, D. M.

1989-11-01

203

Biogeographic relationships among deep-sea hydrothermal vent faunas at global scale  

NASA Astrophysics Data System (ADS)

The discovery of deep-sea hydrothermal vent fauna, kilometres deep in the oceans, is a great achievement of 20th-century marine biology. The deep-sea hydrothermal food web does not directly depend on the sun's energy. Vent communities rely primarily on trophic associations between chemoautotrophic bacteria and consumers. A small number of endemic taxa are adapted to the inhospitable vent environments that are distributed along ridge crests. Where these vent communities originated and how they dispersed are among the important questions ecologists must answer. Here, by statistical analysis of the most comprehensive database ever assembled about deep-sea hydrothermal fauna, we delineate six major hydrothermal provinces in the world ocean and identify seven possible dispersal pathways between adjacent provinces. Our model suggests that the East-Pacific Rise may have played a pivotal role as a centre of dispersal for the hydrothermal fauna. Our data-driven conclusion will have to be tested by phylogenetic studies and completed by surveys of less-explored fields.

Bachraty, C.; Legendre, P.; Desbruyres, D.

2009-08-01

204

Metal concentrations and metallothionein-like protein levels in deep-sea fishes captured near hydrothermal vents in the Mid-Atlantic Ridge off Azores  

NASA Astrophysics Data System (ADS)

The knowledge of metal contamination in deep-sea fishes living in the surroundings of hydrothermal vents 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 vent endemic were collected near three Mid-Atlantic Ridge (MAR) hydrothermal vents (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 vent site 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 hydrothermal vents 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 vent sites.

Company, R.; Felcia, H.; Serafim, A.; Almeida, A. J.; Biscoito, M.; Bebianno, M. J.

2010-07-01

205

Subtidal gastropods consume sulfur-oxidizing bacteria: evidence from coastal hydrothermal vents  

SciTech Connect

The black abalone (Haliotis cracherodii), a commercially important shallow-water gastropod common off White Point, Southern California, is found frequently at subtidal hydrothermal vents within mats of filamentous sulfur-oxidizing bacteria. Foraging vent abalones actively consume the bacteria and confine their nightly feeding forays to bacterial mats surrounding the vents. 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.

Stein, J.L.

1984-02-17

206

Off-axis Symbiosis Found: Characterization and Biogeography of Bacterial1 Symbionts of Bathymodiolus Mussels from Lost City Hydrothermal Vents2  

E-print Network

of Bathymodiolus Mussels from Lost City Hydrothermal Vents2 3 DeChaine1 , E. G., A. E. Bates2 , T. M. Shank3 , & C hydrothermal vents, endosymbionts, methanotroph15 16 Running title: Biogeography of Lost City Symbionts17 18 19 #12;2 Summary19 Organisms at hydrothermal vents inhabit discontinuous chemical "islands" along20 mid

DeChaine, Eric

207

Journal of the Geological Society, London, Vol. 164, 2007, pp. 477479. Printed in Great Britain. Discussion on structure and evolution of hydrothermal vent complexes in the  

E-print Network

. 477 Discussion on structure and evolution of hydrothermal vent complexes in the Karoo Basin, South the paper by Svensen et al. (2006) on South African hydrothermal vents within the Karoo Basin, particularly for their interest in our paper on hydrothermal vent complexes in the Karoo Basin (Svensen et al. 2006). Based

Svensen, Henrik

208

Journal of the Geological Society, London, Vol. 163, 2006, pp. 671682. Printed in Great Britain. Structure and evolution of hydrothermal vent complexes in the Karoo Basin,  

E-print Network

. 671 Structure and evolution of hydrothermal vent complexes in the Karoo Basin, South Africa HENRIK the Karoo Basin, extrusive lava sequences and hydrothermal vent complexes. These last are pipe of the basin. Detailed mapping of two sediment-dominated hydrothermal vent complexes shows

Svensen, Henrik

209

High-pressure hydrogen respiration in hydrothermal vent samples from the deep biosphere  

NASA Astrophysics Data System (ADS)

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 hydrothermal systems, but in situ hydrogen concentrations are largely disregarded in attempts to culture from these sites. 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 hydrothermal chimney and hydrothermally-altered rock samples from the Lost City and Mid-Cayman Rise hydrothermal vent 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 site, 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 site), 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 Hydrothermal Field. Science 307:1428-1434

Morgan-Smith, D.; Schrenk, M. O.

2013-12-01

210

Heat shock protein expression pattern (HSP70) in the hydrothermal vent mussel Bathymodiolus azoricus.  

PubMed

We previously reported evidence of increased levels of DNA damage in the hydrothermal mussel Bathymodiolus azoricus, which suggested that the species was not fully resistant to the natural toxicity of its deep-sea vent environment. In the present study, HSP70 was used as a biomarker of sub-cellular stress. Differences in HSP70 expression pattern were observed between vent sites, typified by different depths/toxicity profiles, and between different mussel tissue types. A comparison of specimens collected by remote operated vehicle (ROV) and acoustically-operated cages showed that less stress (as indicated by changes in HSP70 levels) was induced by the faster cage recovery method. Therefore alternatives to ROV collection should be considered when planning experiments involving live deep sea organisms. Significantly, a positive correlation was found between the levels of DNA strand breakage, as measured using the Comet assay, and HSP70 expression pattern; evidence was also obtained for the constitutive expression of at least one HSP isoform which was located within the cell nucleus. PMID:17316784

Pruski, A M; Dixon, D R

2007-08-01

211

Significance of polysaccharides in microbial physiology and the ecology of hydrothermal vent environments  

NASA Astrophysics Data System (ADS)

Hyperthermophilic microorganisms (those with maximum growth temperatures of 90C and above) are known to inhabit deep-sea hydrothermal vent environments and are suspected of being present in the associated subsurface biosphere. One characteristic of the growth physiology of many heterotrophic hyperthermophiles is the capacity to use complex polysaccharides (e.g., ?- and ?-linked glucans as well as non-glucan hemicellulases) as carbon and energy sources. Polysaccharides may also play an important ecological role in the deep-sea subsurface biosphere as the structural elements of biofilms harboring both heterotrophic and chemolithotrophic microorganisms, representing a range of growth temperatures. Genome sequence analysis of several hyperthermophiles indicates that the enzymatic machinery to synthesize and hydrolyze polysaccharides is present in this group of microorganisms. This is supported by the biochemical characteristics of glycosidases from hyperthermophiles in addition to the observation that several hyperthermophiles form biofilms in pure and co-culture. It remains to be seen if biofilms form the basis for a subsurface biosphere but this possibility seems likely given the physiological characteristics of several hyperthermophiles and mesophiles, representative of microorganisms previously isolated from vent sites.

Pysz, Marybeth A.; Montero, Clemente I.; Chhabra, Swapnil R.; Kelly, Robert M.; Rinker, Kristina D.

212

Microbial geochemistry in rising plumes of two hydrothermal vents at the Mid-Cayman Rise  

NASA Astrophysics Data System (ADS)

Slow and ultraslow spreading ridges comprise ~50% of the global ridge-axis length and are thus relevant to the impact of hydrothermal activity on global ocean biogeochemistry. These ridges host ultramafic vent systems with reducing chemical environments that yield hydrothermal 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 hydrothermal vents impact ocean biogeochemistry, especially in hydrothermal plumes, where vent fluids stimulate chemosynthetic microbial communities and microbes influence the oceanic fate of hydrothermally-sourced elements. Many critical processes occur in the rising portion of hydrothermal 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 hydrothermal plumes. Samples were collected with ROV Jason from two hydrothermal vent 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 hydrothermal 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-vent 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 hydrothermal 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 hydrothermal plumes and outcomes in terms of ocean biogeochemistry.

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.

2012-12-01

213

Microbial community development in deep-sea hydrothermal vents in the Earth and the Enceladus (Invited)  

NASA Astrophysics Data System (ADS)

Over the past 35 years, researchers have explored seafloor deep-sea hydrothermal vent 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 vents. In particular, recent investigations have revealed that the community structure and productivity of chemolithotrophic microbial communities in the deep-sea hydrothermal environments are controlled primarily by variations in the geochemical composition of hydrothermal fluids. This was originally predicted by a thermodynamic calculation of energy yield potential of various chemolithotrophic metabolisms in a simulated hydrothermal mixing zone. The prediction has been finally justified by the relatively quantitative geomicrobiological characterizations in various deep-sea hydrothermal vent 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 hydrothermal vent 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 hydrothermal 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 hydrothermal reaction at high temperatures. Based on these findings, we attempt to built a model of possible hydrothermal fluid/rock reactions and bioavailable energy composition in the mixing zones between the hydrothermal 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 hydrothermal vent systems and the ocean.

Takai, K.; Shibuya, T.; Sekine, Y.; Russell, M. J.

2013-12-01

214

Identification and activity of acetate-assimilating bacteria in diffuse fluids venting from two deep-sea hydrothermal systems.  

PubMed

Diffuse hydrothermal fluids often contain organic compounds such as hydrocarbons, lipids, and organic acids. Microorganisms consuming these compounds at hydrothermal sites 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 hydrothermal 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 hydrothermal 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 hydrothermal 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 hydrothermal vents. PMID:25244359

Winkel, Matthias; Pjevac, Petra; Kleiner, Manuel; Littmann, Sten; Meyerdierks, Anke; Amann, Rudolf; Mumann, Marc

2014-12-01

215

Hydrothermal Vent Plume Discovery and Survey with an Autonomous Underwater Vehicle  

NASA Astrophysics Data System (ADS)

Autonomous Underwater Vehicles (AUVs) can detect and localize deep sea hydrothermal 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 hydrothermal vents in a variety of settings, including the East Pacific Rise (9N and 18S), the Juan de Fuca Ridge (47 54'N), several sites 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 vent sites. 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 vents 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/3791Vent) 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 vent, the lack of a discernable signature while surveying in the same manner that located the ALR/3791vent 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.

Yoerger, D. R.; Collier, R.; Bradley, A. M.

2002-12-01

216

Carbon fluxes from hydrothermal vents off Milos, Aegean Volcanic Arc, and the influence of venting on the surrounding ecosystem.  

NASA Astrophysics Data System (ADS)

The island of Milos, in the Aegean Sea, has extensive hydrothermal fields to the east and southeast of the island with additional venting areas near the entrance to and within the central caldera. A calculation of the total area of the vent fields, based on ship and aerial surveys, suggested that the hydrothermal fields occupy 70 km2, twice the area previously estimated. The vents 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 vents was below the thermocline towards the southwest, in agreement with the prevailing currents. Areas of hydrothermal brine seepage occurred between the gas vents 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 venting 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 vents (up to approximately 8 m away from the vents) 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 vents was over twice as high as that at nearby areas of equivalent water depth, even though vent-obligate fauna were absent. Sediment cementation, caused by reactions with the minerals in the vent 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.

Dando, Paul; Aliani, Stefano; Bianchi, Nike; Kennedy, Hilary; Linke, Peter; Morri, Carla

2014-05-01

217

Spatial and temporal variations in food web structure from newly-opened habitat at hydrothermal vents.  

PubMed

To highlight the spatio-temporal variability of the food web structure of hydrothermal vent fauna from newly-opened habitat, a series of Titanium Ring for Alvinellid Colonization devices (TRACs) was deployed at TICA site on the East Pacific Rise in 2006. This experiment was conducted for periods of 4 days, 13 days and one month and deployments were aligned along a gradient from the basaltic bottom to the vent openings. ?(13)C values of colonists revealed a narrower range of carbon sources in proximity to vent openings in Alvinella pompejana habitat than in Tevnia jerichonana habitat, separated by a distance of four meters. This was possibly due to a spatial change in available food sources with a possible higher contribution of particulate organic matter (POM) to the siboglinid habitat compared to a higher contribution of microbial primary producers such as Epsilonproteobacteria in the alvinellid habitat. Temporal variability was also observed during experimentation in the form of a shift in either ?(13)C and/or ?(15)N values for A. pompejana, Lepetodrilus elevatus, dirivultid copepods and polynoid polychaetes within a one-month window showing first of all, fast tissues turnover and secondly, a possible switch in feeding strategy or food sources. Lepidonotopodium riftense and Branchinotogluma sandersi may have to alternate between detritivorous and predatory feeding strategies. In addition, through the analysis of stable isotope composition of A.pompejana and its episymbionts, we provided evidence that these attached bacteria formed part of the worms' diet during the course of these colonization experiments. PMID:22503949

Gaudron, Sylvie Marylne; Lefebvre, Sbastien; Nunes Jorge, Amandine; Gaill, Franoise; Pradillon, Florence

2012-06-01

218

Melt Supply, Crustal Structure, Tectonic Rifting, and Hydrothermal Venting at the Rainbow Area, 36N MAR  

NASA Astrophysics Data System (ADS)

The MARINER (Mid-Atlantic Ridge INtegrated Experiments at Rainbow) seismic and geophysical mapping experiment was designed to examine the relationship between tectonic rifting, heat/melt supply, and oceanic core complex formation along the Mid-Atlantic Ridge at 36 N, the site of the Rainbow core complex and hydrothermal system. The 5-week experiment was carried out aboard the R/V M. G. Langseth in April-May 2013, and consisted of a 3D active-source seismic tomography experiment, a quasi-3D multi-channel seismic experiment, a 9-month seismicity study using seafloor instruments, dense acoustic mapping of the seafloor, gravity field mapping, and magnetic field mapping. During the tomography experiment, we deployed 46 ocean bottom seismometers in a grid pattern centered on Rainbow. Twenty-six seismic lines were carried out using the Langseth's 36-element source, generating 175,000 seismic records. Overall, the experiment extended across two sections of the Mid-Atlantic Ridge separated by the Rainbow core complex (an 80x105 sq. km area). MARINER seismic, gravity, bathymetry, and acoustic imagery data provide both broad and detailed views of the geologic and geophysical character of the ridge system, emphasizing the strong variability of ridge morphology, tectonics, and lava emplacement. The data indicate that the Rainbow area has been the site of low magma supply for over 1 Myr. The seismic tomography images reveal undulations in crustal structure and thickness across the Rainbow area, indicating temporal variations in melt supply, magmatic processes, and crustal construction. Patterns of seismic anisotropy, which arise from aligned cracks in the subsurface due to tension, suggest a broad semi-circular region of heavily cracked crust surrounding the Rainbow massif, that focuses upwards to a narrow chimney below the Rainbow vent field, potentially indicating the recharge and discharge zones for hydrothermal circulation. The current heat source for the vents may be a small melt lens intruded below the Rainbow massif (as suggested by reflection data), but the tomography does not indicate a significant magmatic system or high-temperature region beneath the Rainbow area. Only one area shows evidence for a ridge-centered high-temperature region at shallow depth, but it occurs beneath the southern ridge section and many kilometers south of the vent field.

Dunn, Robert; Canales, J. Pablo; Sohn, Robert; Arai, Ryuta; Paulatto, Michele

2014-05-01

219

The pH and pCO2 dependence of sulfate reduction in shallow-sea hydrothermal CO2 venting sediments (Milos Island, Greece)  

PubMed Central

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 hydrothermal vent system of Milos, Greece, where pH is naturally decreased by CO2 release. Sediments differed in their physicochemical characteristics with distance from the main site of fluid discharge. Adjacent to the vent site (T ~4075C, pH ~5), maximal sulfate reduction rates (SRR) were observed between pH 5 and 6. SR in hydrothermally influenced sediments decreased at neutral pH. Sediments unaffected by hydrothermal venting (T ~26C, 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 hydrothermal vent system are adapted to low pH and high CO2, while communities at control sites required a higher pH for optimal activity. PMID:23658555

Bayraktarov, Elisa; Price, Roy E.; Ferdelman, Timothy G.; Finster, Kai

2013-01-01

220

Chemoautotrophic Potential of the Hydrothermal Vent Tube Worm, Riftia pachyptila Jones (Vestimentifera)  

Microsoft Academic Search

Trophosome tissue of the hydrothermal vent tube worm, Riftia pachyptila (Vestimentifera), contains high activities of several enzymes associated with chemoautotrophic existence. Enzymes catalyzing synthesis of adenosine triphosphate using energy contained in sulfur compounds such as hydrogen sulfide, and two diagnostic enzymes of the Calvin-Benson cycle of carbon dioxide fixation, ribulosebisphosphate carboxylase and ribulose 5-phosphate kinase, are present at high levels

Horst Felbeck

1981-01-01

221

Hydrocarbon seep and hydrothermal vent paleoenvironments and paleontology: Past developments and future research directions  

Microsoft Academic Search

Hydrocarbon seeps and hydrothermal vents are now known to be common at continental margins and oceanic spreading centers worldwide, exuding fluids rich in CH4 and H2S, and teeming with life based on chemosynthesis. These settings have been implicated as the crucibles for life's origin, and as locales for methane release to the atmosphere from hydrate destabilization during past climate change.

Kathleen A. Campbell

2006-01-01

222

Sulfide Binding by the Blood of the Hydrothermal Vent Tube Worm Riftia pachyptila  

Microsoft Academic Search

The blood of the deep-sea hydrothermal vent tube worm Riftia pachyptila Jones contains a sulfide-binding protein that appears to concentrate sulfide from the environment and may function for sulfide transport to the internal endosymbiotic bacteria contained within the coelomic organ, the trophosome.

Alissa J. Arp; James J. Childress

1983-01-01

223

Methanococcus jannaschii sp. nov., an extremely thermophilic methanogen from a submarine hydrothermal vent  

Microsoft Academic Search

A new extremely thermophilic methane-producing bacterium was isolated from a submarine hydrothermal vent sample collected by a research team from the Woods Hole Oceanographic Institution using the manned submersible ALVIN. The sample was obtained from the base of a white smoker chimney on the East Pacific Rise at 20 50' N latitude and 109 06' W longitude at a depth

W. J. Jones; J. A. Leigh; F. Mayer; C. R. Woese; R. S. Wolfe

1983-01-01

224

Diversity of Thiosulfate-Oxidizing Bacteria from Marine Sediments and Hydrothermal Vents  

Microsoft Academic Search

Species diversity, phylogenetic affiliations, and environmental occurrence patterns of thiosulfate-oxidizing marine bacteria were investigated by using new isolates from serially diluted continental slope and deep-sea abyssal plain sediments collected off the coast of New England and strains cultured previously from Galapagos hydrothermal vent samples. The most frequently obtained new isolates, mostly from 10 3 - and 10 4 -fold dilutions

A. Teske; T. Brinkhoff; G. Muyzer; D. P. Moser; J. Rethmeier; H. W. Jannasch

2000-01-01

225

The formation, oxidation and distribution of pyrite nanoparticles emitted from hydrothermal vents: A laboratory and field based approach  

NASA Astrophysics Data System (ADS)

Recent research identified the presence of nanoparticulate pyrite in hydrothermal vent black smoker emissions, and suggested that these nanoparticles may be a transport pathway for iron from hydrothermal vents to the larger ocean basin. Here, nanoparticulate pyrite was synthesized via a hydrothermal method and oxidized in air- saturated seawater, in order to explore how hydrothermally emitted pyrite forms, and may behave in oxic seawater. Additionally, hydrothermal emissions from the Mid- Atlantic Ridge were investigated for iron and sulfide speciation and reactions relating to pyrite formation. Pyrite was synthesized via both the Fe(II) + S(0) and the FeS + H 2S pathways of pyrite formation, and factors including surfactant and synthesis time were varied in order to modify morphology. The FeS + H 2S formation pathway, which is likely the pathway of pyrite formation occurring at hydrothermal sites, reproduces the pyrite nano and sub- micron particles found in black smoker emissions most closely. The oxidation of these pyrite particles results in an initial oxidation rate that is first order with respect to both the pyrite and oxygen concentration in seawater. This work is unique to previous studies on pyrite oxidation in that it uses synthesized, rather than ground and sieved pyrite, and uses seawater as the medium of oxidation. Along with the rate data, this study also demonstrates that the initial oxide formed from pyrite oxidation under these conditions is poorly crystalline and contains Fe(II) and Fe(III). Pyrite nanoparticles were identified at each of the three sites investigated at the Mid-Atlantic Ridge (Rainbow, TAG and Snakepit), and their presence at these sites, when combined with previous data from Lau Basin and EPR 9 N demonstrates that they are likely to be a ubiquitous component of black- smoker hydrothermal emissions. The Rainbow site exhibited the highest concentration of nanoparticulate pyrite measured anywhere to date (1.15 mM). The potential rates of pyrite formation during hydrothermal buoyant plume rise are investigated, as are the rates of formation for different iron- containing particulates including FeS, silicate formation, and Fe(II) oxidation.

Gartman, Amy

226

Bottom sediments and pore waters near a hydrothermal vent in Lake Baikal (Frolikha Bay)  

USGS Publications Warehouse

We discuss the redox environments and the compositions of bottom sediments and sedimentary pore waters in the region of a hydrothermal vent in Frolikha Bay, Lake Baikal. According to our results, the submarine vent 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 vent have a specific enrichment in major and minor constituents, hydrothermal 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.

Granina, L.Z.; Klerkx, J.; Callender, E.; Leermakers, M.; Golobokova, L.P.

2007-01-01

227

Fluid flow and sound generation at hydrothermal vent fields. Doctoral thesis  

SciTech Connect

Several experiments in this thesis examine methods to measure and monitor fluid flow from hydrothermal vent fields. Simultaneous velocity temperature, and conductivity data were collected in the convective flow emanating from a hydrothermal vent 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 hydrothermal 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 hydrothermal 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 hydrothermal sound fields showing anomalous high power and low frequency noise associated with vents is due to processes other than jet noise.

Little, S.A.

1988-04-01

228

Recruitment of marine invertebrates to hard substrates at deep-sea hydrothermal vents on the East Pacific Rise and Galapagos spreading center  

NASA Astrophysics Data System (ADS)

Recruitment panels were placed at and near hydrothermal vent communities at three sites on the Galapagos spreading center and one site on the East Pacific Rise at 21N. Deployment periods ranged from 26 days (Clam Acres, 21N) to 260-320 days (Rose Garden, Garden of Eden, Mussel Bed, GSC) to 1216 days (Clam Acres). Recruitment of gastropod post-larvae and juveniles was observed on arrays deployed at Clam Acres for 26 days. Regardless of length of deployment, populations of polychaetes, mollusks, and barnacles colonizing the panels were predominantly post-larval, juvenile, or sub-adult stages. We suggest that some combination of competition, migration, and predation maintains these populations in immature stages. Size distributions of individuals within a taxon on panels deployed for 1216 days are broad, suggesting intermittent or continuous recruitment in many of the vent-associated species rather than a single episodic recruitment event. Folliculinid and foraminiferan protozoans were the most abundant eucaryotic organisms colonizing long-term deployments at Clam Acres. On the Galapagos spreading center, level of recruitment differed among the vent sites, with Rose Garden > Garden of Eden ? Mussel Bed. Recruitment of vent-associated species was greater on panels placed within vent communities compared to panels placed adjacent to these communities. This observation is consistent with the maintenance of vent communities in discrete regions of hydrothermal flux.

Van Dover, Cindy Lee; Berg, Carl J.; Turner, Ruth D.

1988-10-01

229

Geochemical controls on hydrothermal fluids from the Kairei and Edmond Vent Fields, 23-25S, Central Indian Ridge  

NASA Astrophysics Data System (ADS)

Prior to 2000, no mid-ocean ridge hydrothermal systems were identified and sampled in the Indian Ocean. The Kairei field, Central Indian Ridge, was discovered and sampled in 2000 (Gamo et al., 2001; Hashimoto et al., 2001). This paper reports the chemical composition of hydrothermal fluids collected in 2001 from both the Kairei and newly discovered Edmond hydrothermal systems. Data are used to infer subsurface processes and conditions at the two sites, as well as to place them within the global context of known hydrothermal sites on the mid-ocean ridge system. While both sites are located on the intermediate spreading Central Indian Ridge, their hydrologic systems have affinities with those observed on slow spreading ridges. Although the compositions of fluids from the four individual vents sampled at Edmond and the three individual vents sampled at Kairei vary respectively, our interpretation is that a single source fluid at each site is subsequently modified by processes including phase separation, subsurface mixing with seawater, and deposition and/or remobilization of metal-sulfide deposits to generate the observed range of compositions. Both fields are located ?6 km from the neovolcanic zone, on steps on the east wall of the axial valley, with the Edmond field 160 km north of Kairei and almost 1000 m deeper (3300 versus 2450 m). The Edmond fluids are extremely hot, with maximum measured temperatures of 382C compared to 365C for Kairei. All of the fluids sampled have chlorinities greater than local ambient seawater due to phase separation of seawater at supercritical conditions. Visual observations suggest both sites have been active for a substantial period of time, again similar to observations of slow spreading ridges. Our chemical data suggest that the substrate underlying Kairei is highly altered, while that at Edmond is not. Significant albitization appears to be occurring below the Edmond field, but not at Kairei. The Edmond fluids are by far the hottest brines yet observed venting from a mid-ocean ridge hydrothermal site, resulting in unusually high concentrations of several transition metals.

Gallant, R. M.; von Damm, K. L.

2006-06-01

230

Comparative Population Structure of Two Deep-Sea Hydrothermal-Vent-Associated Decapods (Chorocaris sp. 2 and Munidopsis lauensis) from Southwestern Pacific Back-Arc Basins  

PubMed Central

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 vent effluent for survival. Relatively little attention has been paid to vent-associated species that are not exclusively dependent on chemosynthetic ecosystems. Here we assess connectivity and population structure of two vent-associated invertebratesthe shrimp Chorocaris sp. 2 and the squat lobster Munidopsis lauensisthat are common at deep-sea hydrothermal vents in the western Pacific. While Chorocaris sp. 2 has only been observed at hydrothermal vent sites, M. lauensis can be found throughout the deep sea but occurs in higher abundance around the periphery of active vents We sequenced mitochondrial COI genes and deployed nuclear microsatellite markers for both species at three sites 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 vent-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 hydrothermal vent ecosystems. PMID:24983244

Thaler, Andrew David; Plouviez, Sophie; Saleu, William; Alei, Freddie; Jacobson, Alixandra; Boyle, Emily A.; Schultz, Thomas F.; Carlsson, Jens; Van Dover, Cindy Lee

2014-01-01

231

Comparative population structure of two deep-sea hydrothermal-vent-associated decapods (Chorocaris sp. 2 and Munidopsis lauensis) from southwestern Pacific back-arc basins.  

PubMed

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 vent effluent for survival. Relatively little attention has been paid to vent-associated species that are not exclusively dependent on chemosynthetic ecosystems. Here we assess connectivity and population structure of two vent-associated invertebrates--the shrimp Chorocaris sp. 2 and the squat lobster Munidopsis lauensis--that are common at deep-sea hydrothermal vents in the western Pacific. While Chorocaris sp. 2 has only been observed at hydrothermal vent sites, M. lauensis can be found throughout the deep sea but occurs in higher abundance around the periphery of active vents We sequenced mitochondrial COI genes and deployed nuclear microsatellite markers for both species at three sites 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 vent-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 hydrothermal vent ecosystems. PMID:24983244

Thaler, Andrew David; Plouviez, Sophie; Saleu, William; Alei, Freddie; Jacobson, Alixandra; Boyle, Emily A; Schultz, Thomas F; Carlsson, Jens; Van Dover, Cindy Lee

2014-01-01

232

Previously unsuspected dietary habits of hydrothermal vent fauna: the bactivorous shrimp Rimicaris hybisae can be carnivorous or even cannibalistic  

NASA Astrophysics Data System (ADS)

Most hydrothermal vents 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 hydrothermal vents of the Mid-Cayman Rise (MCR), revealing previously unknown life-history traits of the alvinocarid shrimp species Rimicaris hybisae. We also demonstrate that stable carbon isotope ratios (?13C values) are an excellent tracer of trophic positions in these ecosystems, in spite of recent findings arguing otherwise. Two hydrothermal vent fields have been described at the ultra-slow spreading ridge of the MCR. These include the world's deepest hydrothermal vents (Piccard field ~4985 m), which support a food web, which includes bactivorous shrimp and carnivorous anemones. The nearby Von Damm vent 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 vent fields and shows a high degree of spatial variability in population structure and reproductive features. In previous work it has been considered bactivorous. Large variations in tissue ?13C values remained largely unexplained, and it has been argued that ?13C values are not a good food web tracer in hydrothermal vent ecosystems. We observed that shrimp tended to be either in dense aggregations on active chimneys or more sparsely distributed, peripheral shrimp in ambient or near-ambient temperatures. With the hypothesis that varying ?13C values show real differences in food sources between individuals and that shrimp in different locales might have different diets, we collected shrimp from both environments at the Von Damm site during E/V Nautilus (NA034, August 2013) and examined their gut contents. Stomach contents of all shrimp from dense aggregations at the Von Damm field (n=18) consisted of white, amorphous material that resembled bacteria. Sparsely distributed peripheral shrimp (~1 m from dense aggregations) had stomachs filled with fragments of crustacean exoskeleton (5/13), a mixture of bacteria-like material and crustacean exoskeleton (3/13), or bacteria-like material only (5/13). We then analyzed the ?13C, ?15N and ?34S compositions of the shrimp gut contents. We show that R. hybisae switches its diet from exclusively chemosynthetic bacteria to crustacea during its life history. This is reflected in dramatically lower ?13C values of shrimp tissues, and slightly elevated ?15N values. To further support our findings, measurements of ?34S values on the same individuals and their gut contents are ongoing. Our contribution to disentangling the food web around the MCR hydrothermal vents fields helps quantify their carbon budget and determine their role in ocean carbon cycling.

Versteegh, Emma; Van Dover, Cindy; Coleman, Max

2014-05-01

233

Biological Communities at the Florida Escarpment Resemble Hydrothermal Vent Taxa  

Microsoft Academic Search

Dense biological communities of large epifaunal taxa similar to those found along ridge crest vents 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

C. K. Paull; B. Hecker; R. Commeau; R. P. Freeman-Lynde; C. Neumann; W. P. Corso; S. Golubic; J. E. Hook; E. Sikes; J. Curray

1984-01-01

234

Hydrothermal Vent Sampler: Does Life Exist in High Temperature Environments?  

NASA Technical Reports Server (NTRS)

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. Vents 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 vents 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 vents. The vent 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.

Rivadeneyra, Cesar R.

2005-01-01

235

Expression patterns of mRNAs for methanotrophy and thiotrophy in symbionts of the hydrothermal vent mussel Bathymodiolus puteoserpentis  

PubMed Central

The hydrothermal vent mussel Bathymodiolus puteoserpentis (Mytilidae) from the Mid-Atlantic Ridge hosts symbiotic sulfur- and methane-oxidizing bacteria in its gills. In this study, we investigated the activity and distribution of these two symbionts in juvenile mussels from the Logatchev hydrothermal vent field (1445?N Mid-Atlantic Ridge). Expression patterns of two key genes for chemosynthesis were examined: pmoA (encoding subunit A of the particulate methane monooxygenase) as an indicator for methanotrophy, and aprA (encoding the subunit A of the dissimilatory adenosine-5?-phosphosulfate reductase) as an indicator for thiotrophy. Using simultaneous fluorescence in situ hybridization (FISH) of rRNA and mRNA we observed highest mRNA FISH signals toward the ciliated epithelium where seawater enters the gills. The levels of mRNA expression differed between individual specimens collected in a single grab from the same sampling site, whereas no obvious differences in symbiont abundance or distribution were observed. We propose that the symbionts respond to the steep temporal and spatial gradients in methane, reduced sulfur compounds and oxygen by modifying gene transcription, whereas changes in symbiont abundance and distribution take much longer than regulation of mRNA expression and may only occur in response to long-term changes in vent fluid geochemistry. PMID:21734728

Wendeberg, Annelie; Zielinski, Frank U; Borowski, Christian; Dubilier, Nicole

2012-01-01

236

Thermococcus chitonophagus sp. nov., a novel, chitin-degrading, hyperthermophilic archaeum from a deep-sea hydrothermal vent environment  

Microsoft Academic Search

From a hydrothermal vent site off the Mexican west coast (2050?N, 10906?W) at a depth of 2,600 m, a novel, hyperthermophilic,\\u000a anaerobic archaeum was isolated. Cells were round to slightly irregular cocci, 1.22.5 ?m in diameter and were motile by means\\u000a of a tuft of flagella. The new isolate grew between 60 and 93C (optimum: 85C), from pH 3.5 to

Robert Huber; Josef Sthr; Sabine Hohenhaus; Reinhard Rachel; Siegfried Burggraf; Holger W. Jannasch; Karl O. Stetter

1995-01-01

237

Magnetic characteristics of possible hydrothermal vents in TA 25 and TA26 seamounts, the Lau Basin  

NASA Astrophysics Data System (ADS)

The deep sea three component magnetic survey was conducted in the western (site A) and eastern (site B) slopes of the caldera of TA25 seamount and the summit area of TA26 seamount, the Lau Basin, the southwestern Pacific, at Jan. 2012, using German R/V SONNE and ROV (Remotely Operated Vehicle) of ROPOS Co. The magnetic survey lines were the 29 N-S lines (TA25-East : 12 lines, TA25-West : 11 lines, TA26 : 6 lines) with about 100 m spacing and about 50 m above seafloor. For the magnetic survey, the magnetometer sensor was attached with the line frame of ROV and the data logger and motion sensor in ROV. A motion sensor (Octans) provided us the data of pitch, roll, yaw for the correction of the magnetic data to the motion of ROV. The data of the magnetometer and motion sensors and the USBL(Ultra Short Base Line) data of the position of ROV were recorded on a notebook through the optical cable of ROV. Hydrothermal fluids over Curie temperature can quickly alter or replace the iron-rich magnetic minerals, reducing the magnetic remanence of the crustal rocks, in some cases to near 0 A/m magnetization. The magnetic anomaly map of TA25 site A shows high anomalies in the central part and low anomalies in the northern part, ranging from about -500 to 500 nT. The magnetization map, calculated by the inversion of the bathymetry and the magnetic anomaly, represents low anomalous zones over the south-western part and the northern part of the area. The magnetic anomaly map of TA25 site B displays high anomalies in the southeastern part and low anomalies in the central and eastern parts, ranging from about -700 to 800 nT. The low magnetization zones occur over the western part and central part of the area. The high magnetic anomalies of the survey area of TA26 are located in the north and northeastern parts and low anomalies in the southeastern part, with the magnetic anomaly range from about -2000 to 1600 nT. The magnetization map shows east-west trend low anomalous zones in the area. The low anomalous magnetization zones of the survey areas usually appear in groups. Some of these low magnetization zones are well matched with the chimney sites or hydrothermal altered areas, based on the previous results of video or rock sampling. The low magnetization zones are likely to be the possible hydrothermal vents.

Kim, Chang Hwan; Choi, Soon Young; Park, Chan Hong

2014-05-01

238

Sulfur and oxygen isotope insights into sulfur cycling in shallow-sea hydrothermal vents, Milos, Greece  

PubMed Central

Shallow-sea (5m depth) hydrothermal venting off Milos Island provides an ideal opportunity to target transitions between igneous abiogenic sulfide inputs and biogenic sulfide production during microbial sulfate reduction. Seafloor vent features include large (>1m2) white patches containing hydrothermal minerals (elemental sulfur and orange/yellow patches of arsenic-sulfides) and cells of sulfur oxidizing and reducing microorganisms. Sulfide-sensitive film deployed in the vent and non-vent 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 vent organisms and hydrothermalism, the sulfur and oxygen isotope composition of pore fluids did not permit delineation of a biotic signal separate from an abiotic signal. Hydrogen sulfide (H2S) in the free gas had uniform ?34S values (2.5??0.28, n?=?4) that were nearly identical to pore water H2S (2.7??0.36, n?=?21). In pore water sulfate, there were no paired increases in ?34SSO4 and ?18OSO4 as expected of microbial sulfate reduction. Instead, pore water ?34SSO4 values decreased (from approximately 21 to 17) as temperature increased (up to 97.4C) across each hydrothermal feature. We interpret the inverse relationship between temperature and ?34SSO4 as a mixing process between oxic seawater and 34S-depleted hydrothermal inputs that are oxidized during seawater entrainment. An isotope mass balance model suggests secondary sulfate from sulfide oxidation provides at least 15% of the bulk sulfate pool. Coincident with this trend in ?34SSO4, the oxygen isotope composition of sulfate tended to be 18O-enriched in low pH (<5), high temperature (>75C) pore waters. The shift toward high ?18OSO4 is consistent with equilibrium isotope exchange under acidic and high temperature conditions. The source of H2S contained in hydrothermal fluids could not be determined with the present dataset; however, the end-member ?34S value of H2S discharged to the seafloor is consistent with equilibrium isotope exchange with subsurface anhydrite veins at a temperature of ~300C. Any biological sulfur cycling within these hydrothermal systems is masked by abiotic chemical reactions driven by mixing between low-sulfate, H2S-rich hydrothermal fluids and oxic, sulfate-rich seawater. PMID:25183951

2014-01-01

239

Sulfur and oxygen isotope insights into sulfur cycling in shallow-sea hydrothermal vents, Milos, Greece.  

PubMed

Shallow-sea (5m depth) hydrothermal venting off Milos Island provides an ideal opportunity to target transitions between igneous abiogenic sulfide inputs and biogenic sulfide production during microbial sulfate reduction. Seafloor vent features include large (>1m(2)) white patches containing hydrothermal minerals (elemental sulfur and orange/yellow patches of arsenic-sulfides) and cells of sulfur oxidizing and reducing microorganisms. Sulfide-sensitive film deployed in the vent and non-vent 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 vent organisms and hydrothermalism, 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 ?(34)S 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 ?(34)SSO4 and ?(18)OSO4 as expected of microbial sulfate reduction. Instead, pore water ?(34)SSO4 values decreased (from approximately 21 to 17) as temperature increased (up to 97.4C) across each hydrothermal feature. We interpret the inverse relationship between temperature and ?(34)SSO4 as a mixing process between oxic seawater and (34)S-depleted hydrothermal 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 ?(34)SSO4, the oxygen isotope composition of sulfate tended to be (18)O-enriched in low pH (<5), high temperature (>75C) pore waters. The shift toward high ?(18)OSO4 is consistent with equilibrium isotope exchange under acidic and high temperature conditions. The source of H2S contained in hydrothermal fluids could not be determined with the present dataset; however, the end-member ?(34)S value of H2S discharged to the seafloor is consistent with equilibrium isotope exchange with subsurface anhydrite veins at a temperature of ~300C. Any biological sulfur cycling within these hydrothermal systems is masked by abiotic chemical reactions driven by mixing between low-sulfate, H2S-rich hydrothermal fluids and oxic, sulfate-rich seawater. PMID:25183951

Gilhooly, William P; Fike, David A; Druschel, Gregory K; Kafantaris, Fotios-Christos A; Price, Roy E; Amend, Jan P

2014-01-01

240

Evolutionary Strategies of Viruses, Bacteria and Archaea in Hydrothermal Vent Ecosystems Revealed through Metagenomics  

PubMed Central

The deep-sea hydrothermal vent 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 hydrothermal systems through comparative analysis of a cellular and viral metagenome, collected by size fractionation of high temperature fluids from a diffuse flow hydrothermal vent. 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 hydrothermal vent viruses to integrate into hosts, facilitate horizontal gene transfer, and express or transfer genes that manipulate the hosts functional capabilities. PMID:25279954

Anderson, Rika E.; Sogin, Mitchell L.; Baross, John A.

2014-01-01

241

Widespread Occurrence of Two Carbon Fixation Pathways in Tubeworm Endosymbionts: Lessons from Hydrothermal Vent Associated Tubeworms from the Mediterranean Sea  

PubMed Central

Vestimentiferan tubeworms (siboglinid polychetes) of the genus Lamellibrachia are common members of cold seep faunal communities and have also been found at sedimented hydrothermal vent sites 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 hydrothermal vent field in the Western Mediterranean Sea. The tubeworms, which are the first reported vent-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 vent 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 sites 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

Thiel, Vera; Hgler, Michael; Blmel, Martina; Baumann, Heike I.; Grtner, Andrea; Schmaljohann, Rolf; Strauss, Harald; Garbe-Schnberg, Dieter; Petersen, Sven; Cowart, Dominique A.; Fisher, Charles R.; Imhoff, Johannes F.

2012-01-01

242

Selective predation by the zoarcid fish Thermarces cerberus at hydrothermal vents  

NASA Astrophysics Data System (ADS)

This study investigates predation by the vent zoarcid fish Thermarces cerberus through gastrointestinal analyses of 27 specimens collected with the submersible ALVIN at vents at 950'N on the East Pacific Rise. T. cerberus fed most frequently on gastropod mollusks (mainly Lepetodrilus elevatus) and amphipod crustaceans (mainly Ventiella sulfuris). Species found occasionally in high abundance included the swarming amphipod Halice hesmonectes and the snail Cyathermia naticoides. Other items also found in gastrointestinal tracts, but in very low numbers, included polychaete worms, crustaceans and unidentified tissue clumps. The comparison between the size distribution of L. elevatus limpets ingested by T. cerberus and those found attached to vestimentiferan tubes suggest that the fish may selectively prey on large limpets. If the selective removal of large Lepetodrilus spp. limpets by T. cerberus does occur, then it would have potential community-level consequences at hydrothermal vents, since these mobile gastropods appear to inhibit the settlement of sessile vent species, including tube-building worms. Our results suggest possible direct and indirect effects of T. cerberus on benthic community structure at hydrothermal vents on the East Pacific Rise.

Sancho, G.; Fisher, C. R.; Mills, S.; Micheli, F.; Johnson, G. A.; Lenihan, H. S.; Peterson, C. H.; Mullineaux, L. S.

2005-05-01

243

ORIGINAL ARTICLE Ultra-diffuse hydrothermal venting supports  

E-print Network

& Science University, Beaverton, OR, USA; 9 Department of Soil, Water, and Climate, University of Minnesota of the mat ecosystem. We suggest that the biogenic FeMO Deep hydrothermal deposit represents a modern analog Baby Bare seamount on the eastern flank of the Juan de Fuca Ridge (Wheat and Mottl, 2000), Lost City

Moyer, Craig

244

Rare earth elements in seawater near hydrothermal vents  

Microsoft Academic Search

Rare earth element (REE) patterns in the deep Pacific are strongly depleted in the lighter elements and have a large negative cerium anomaly. These REE patterns and associated concentration-depth profiles are maintained by regeneration in deep waters modified by preferential scavenging of the lighter elements. Scavenging by iron- and manganese-rich hydrothermal plumes might explain why vast areas of sediments far

G. Klinkhammer; H. Elderfield; A. Hudson

1983-01-01

245

Detection of Putatively Thermophilic Anaerobic Methanotrophs in Diffuse Hydrothermal Vent Fluids  

PubMed Central

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 vent fluids from deep-sea hydrothermal vents. 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 vent fluid samples from deep-sea hydrothermal vents in the Pacific Ocean, and sequences belonging to the ANME-1 cluster were detected in four individual vents. Phylotypes belonging to the ANME-1GBa group dominated in clone libraries from three of these vents. Our findings provide evidence of existence of a putatively extremely thermophilic group of methanotrophic archaea that occur in geographically and geologically distinct marine hydrothermal habitats. PMID:23183981

Huber, Julie A.; Chernyh, Nikolay A.; Bonch-Osmolovskaya, Elizaveta A.; Lebedinsky, Alexander V.

2013-01-01

246

Euryhaline Halophilic Microorganisms From the Suiyo Seamount Hydrothermal Vents  

Microsoft Academic Search

The euryhaline halophilic microorganisms grow in a wide salinity range from 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 vents and seeps, and from Antarctic sea ice and terrains. We have isolated the euryhaline strains independently from a

T. Okamoto; H. Kimura; A. Maruyama; T. Naganuma

2002-01-01

247

Modeling microbial reaction rates in a submarine hydrothermal vent chimney wall  

NASA Astrophysics Data System (ADS)

The fluids emanating from active submarine hydrothermal vent 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, hydrothermal fluid, minerals and microorganisms inside chimney walls, none provide a fully integrated approach to quantifying the biogeochemistry of these hydrothermal systems. In an effort to remedy this, a fully coupled biogeochemical reaction-transport model of a hydrothermal vent 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 vent 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 vent 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 hydrothermal systems and can be used to constrain the role of microbial activity in the deep subsurface.

LaRowe, Douglas E.; Dale, Andrew W.; Aguilera, David R.; L'Heureux, Ivan; Amend, Jan P.; Regnier, Pierre

2014-01-01

248

Bathymetric influence on dissolved methane in hydrothermal plumes revealed by concentration and stable carbon isotope measurements at newly discovered venting sites on the Central Indian Ridge (11-13S)  

NASA Astrophysics Data System (ADS)

Methane is a useful tracer for studying hydrothermal discharge, especially where the source fluids are of low temperature and lack metal precipitates. However, the dual origins of deep-sea methane, both chemical and biological, complicate the interpretation of methane observations. Here, we use both the concentration and stable carbon isotopic composition (?13C) of dissolved methane to trace hydrothermal plumes and identify the source and behavior of methane at two sites of newly discovered hydrothermal activity on the Central Indian Ridge (11-13S). At both sites, methane and optical anomalies between 2500 and 3500 m at all stations indicate active hydrothermal discharge. We compared methane concentrations and ?13C at three stations, two (CTIR110136 and CTIR110208) with the most prominent anomalies at each site, and a third (CTIR110140) with near-background methane values. At stations CTIR110136 and CTIR110208, the concentration and ?13C of methane in distinct plumes ranged from 3.3 to 42.3 nmol kg-1 and -30.0 to -15.4, respectively, compared to deep-water values of 0.5 to 1.2 nmol kg-1 and -35.1 to -28.9 at the station with a near-background distal plume (CTIR110140). ?13C was highest in the center of the plumes at CTIR110136 (-15.4) and CTIR110208 (-17.8). From the plume values we estimate that the ?13C of methane in the hydrothermal fluids at these stations was approximately -19 and thus the methane was most likely derived from magmatic outgassing or the chemical synthesis of inorganic matter. We used the relationship between ?13C and methane concentration to examine the behavior of methane at the plume stations. In the CTIR110208 plume, simple physical mixing was likely the major process controlling the methane profile. In the CTIR110136 plume we interpret a more complicated relationship as resulting from microbial oxidation as well as physical mixing. We argue that this difference in methane behavior between the two areas stems from a distinct bathymetric dissimilarity between the two stations. The location of CTIR110208 on the open slope of a ridge allowed rapid plume dispersion and physical mixing, whereas the location of CTIR110136 in a small basin surrounded by wall structures inhibited physical mixing and enhanced microbial oxidation.

You, Ok-Rye; Son, Seung Kyu; Baker, Edward T.; Son, Juwon; Kim, Mi Jin; Barcelona, Michael J.; Kim, Moonkoo

2014-09-01

249

Reconstructing the oxygen isotope composition of late Cambrian and Cretaceous hydrothermal vent fluid  

NASA Astrophysics Data System (ADS)

Oxygen isotope analyses (?18O) of 16 quartz-epidote pairs from late Cambrian (Betts Cove and Mings Bight, Newfoundland), Ordovician (Thetford Mines, Qubec, Canada) and Cretaceous (Troodos, Cyprus) ophiolites are used to calculate the ?18O of the hydrothermal 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 ?18O of submarine hydrothermal vent fluid has varied between the late Cambrian, Cretaceous and today. The range of calculated ?18O values of vent fluid (-4 to +7.4) is larger than that of modern seafloor hydrothermal vent fluid (0 to +4). We employ two numerical models to ascertain whether this range is most consistent with changes in paleo-seawater ?18O or with changes in the reactive flow path in ancient hydrothermal systems. A static calculation of the vent fluid oxygen isotope composition as a function of the water-rock ratio suggests that in an ocean with a lower ?18O than today, the range of vent fluid ?18O should be larger. Our data, however, show little evidence that the ?18O 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 ?18O of vent fluid in contact with rock. Our 87Sr/86Sr and ?18O for Cretaceous epidotes suggest the strontium concentration of the Cretaceous oceans may have been much higher than at present. The 87Sr/86Sr and ?18O data from Cambrian epidotes are strikingly different from the younger samples, and are difficult to model unless fluid-rock interaction in the Cambrian hydrothermal 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 hydrothermal fluids to have 87Sr/86Sr closer to that of seawater than in modern systems.

Turchyn, Alexandra V.; Alt, Jeffrey C.; Brown, Shaun T.; DePaolo, Donald J.; Coggon, Rosalind M.; Chi, Guoxiang; Bdard, Jean H.; Skulski, Thomas

2013-12-01

250

Microbial iron uptake as a mechanism for dispersing iron from deep-sea hydrothermal vents.  

PubMed

Deep-sea hydrothermal vents are a significant source of oceanic iron. Although hydrothermal iron rapidly precipitates as inorganic minerals on mixing with seawater, it can be stabilized by organic matter and dispersed more widely than previously recognized. The nature and source of this organic matter is unknown. Here we show that microbial genes involved in cellular iron uptake are highly expressed in the Guaymas Basin deep-sea hydrothermal plume. The nature of these microbial iron transporters, taken together with the low concentration of dissolved iron and abundance of particulate iron in the plume, indicates that iron minerals are the target for this microbial scavenging and uptake. Our findings indicate that cellular iron uptake is a major process in plume microbial communities and suggest new mechanisms for generating Fe-C complexes. This 'microbial iron pump' could represent an important mode of converting hydrothermal iron into bioavailable forms that can be dispersed throughout the oceans. PMID:24496055

Li, Meng; Toner, Brandy M; Baker, Brett J; Breier, John A; Sheik, Cody S; Dick, Gregory J

2014-01-01

251

Microearthquakes beneath the Hydrothermal Vent Fields on the Endeavour Segment of the Juan de Fuca Ridge: Results from the Keck Seismic\\/Hydrothermal Observatory  

Microsoft Academic Search

The W.M. Keck Foundation is supporting the operation of a small seismic network in the vicinity of the hydrothermal vent fields on the central portion of the Endeavour Segment of the Juan de Fuca Ridge. This is part of a program to conduct prototype seafloor observatory experiments to monitor the relationships between episodic deformation, fluid venting and microbial productivity at

D. Bowman; J. Parker; W. Wilcock; E. Hooft; A. Barclay; D. Toomey; P. McGill; D. Stakes; C. Schmidt; H. Patel

2005-01-01

252

Biotic and abiotic interactions of deep-sea hydrothermal vent-endemic fish on the East Pacific Rise  

E-print Network

A study of the ecology of fish endemic to hydrothermal vents on the East Pacific Rise was undertaken utilizing a variety of techniques, focusing on the bythitid Thermichthys hollisi. Stable isotope and gut content analyses ...

Buckman, Kate Lynn

2009-01-01

253

Absolute Magnetization Distribution on Back-arc Spreading Axis Hosting Hydrothermal Vents; Insight from Shinkai 6500 Magnetic Survey  

NASA Astrophysics Data System (ADS)

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 hydrothermal 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 hydrothermal vent fields (Snail, Yamanaka, Archean, Pica, and Urashima sites) have been found in both on- and off-axis areas of the active back-arc spreading center, to detect signals from hydrothermally 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 hydrothermal vent sites. This result is consistent with the equivalent magnetization distribution obtained from previous AUV survey data. The areas of low magnetization are also consistent with hydrothermal deposits identified in video records. These results suggest that low magnetic signals are due to hydrothermal alteration zones where host rocks are demagnetized by hydrothermal circulation. The low magnetization zones around the off-axis vent sites are about ten times wider than those surrounding the on-axis sites, possibly reflecting the longer duration of hydrothermal circulation at these sites. 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 hydrothermal rapid alteration and the low-temperature gradual alteration processes.

Fujii, M.; Okino, K.; Honsho, C.; Mochizuki, N.; Szitkar, F.; Dyment, J.

2013-12-01

254

Phylogenetic characterization of the epibiotic bacteria associated with the hydrothermal vent polychaete Alvinella pompejana.  

PubMed

Alvinella pompejana is a polychaetous annelid that inhabits active deep-sea hydrothermal vent sites along the East Pacific Rise, where it colonizes the walls of actively venting high-temperature chimneys. An abundant, morphologically diverse epibiotic microflora is associated with the worm's dorsal integument, with a highly integrated filamentous morphotype clearly dominating the microbial biomass. It has been suggested that this bacterial population participates in either the nutrition of the worm or in detoxification of the worm's immediate environment. The primary goal of this study was to phylogenetically characterize selected epibionts through the analysis of 16S rRNA gene sequences. Nucleic acids were extracted from bacteria collected from the dorsal surface of A. pompejana. 16S rRNA genes were amplified with universal bacterial primers by the PCR. These genes were subsequently cloned, and the resulting clone library was screened by restriction fragment length polymorphism analysis to identify distinct clone types. The restriction fragment length polymorphism analysis identified 32 different clone families in the library. Four of these families were clearly dominant, representing more than 65% of the library. Representatives from the four most abundant clone families were chosen for complete 16S rRNA gene sequencing and phylogenetic analysis. These gene sequences were analyzed by a variety of phylogenetic inference methods and found to be related to the newly established epsilon subdivision of the division Proteobacteria. Secondary structural model comparisons and comparisons of established signature base positions in the 16S rRNA confirmed the placement of the Alvinella clones in the epsilon subdivision of the Proteobacteria. PMID:7544093

Haddad, A; Camacho, F; Durand, P; Cary, S C

1995-05-01

255

Characterization of a novel spirochete associated with the hydrothermal vent polychaete annelid, Alvinella pompejana.  

PubMed

A highly integrated, morphologically diverse bacterial community is associated with the dorsal surface of Alvinella pompejana, a polychaetous annelid that inhabits active high-temperature deep-sea hydrothermal vent sites along the East Pacific Rise (EPR). Analysis of a previously prepared bacterial 16S ribosomal DNA (rDNA) library identified a spirochete most closely related to an endosymbiont of the oligochete Olavius loisae. This spirochete phylotype (spirochete A) comprised only 2.2% of the 16S rDNA clone library but appeared to be much more dominant when the same sample was analyzed by denaturing gradient gel electrophoresis (DGGE) and the terminal restriction fragment length polymorphism procedure (12 to 18%). PCR amplification of the community with spirochete-specific primers used in conjunction with DGGE analysis identified two spirochete phylotypes. The first spirochete was identical to spirochete A but was present in only one A. pompejana specimen. The second spirochete (spirochete B) was 84.5% similar to spirochete A and, more interestingly, was present in the epibiont communities of all of the A. pompejana specimens sampled throughout the geographic range of the worm (13 degrees N to 32 degrees S along the EPR). The sequence variation of the spirochete B phylotype was less than 3% for the range of A. pompejana specimens tested, suggesting that a single spirochete species was present in the A. pompejana epibiotic community. Additional analysis of the environments surrounding the worm revealed that spirochetes are a ubiquitous component of high-temperature vents and may play an important role in this unique ecosystem. PMID:11133434

Campbell, B J; Cary, S C

2001-01-01

256

Phylogenetic characterization of the epibiotic bacteria associated with the hydrothermal vent polychaete Alvinella pompejana.  

PubMed Central

Alvinella pompejana is a polychaetous annelid that inhabits active deep-sea hydrothermal vent sites along the East Pacific Rise, where it colonizes the walls of actively venting high-temperature chimneys. An abundant, morphologically diverse epibiotic microflora is associated with the worm's dorsal integument, with a highly integrated filamentous morphotype clearly dominating the microbial biomass. It has been suggested that this bacterial population participates in either the nutrition of the worm or in detoxification of the worm's immediate environment. The primary goal of this study was to phylogenetically characterize selected epibionts through the analysis of 16S rRNA gene sequences. Nucleic acids were extracted from bacteria collected from the dorsal surface of A. pompejana. 16S rRNA genes were amplified with universal bacterial primers by the PCR. These genes were subsequently cloned, and the resulting clone library was screened by restriction fragment length polymorphism analysis to identify distinct clone types. The restriction fragment length polymorphism analysis identified 32 different clone families in the library. Four of these families were clearly dominant, representing more than 65% of the library. Representatives from the four most abundant clone families were chosen for complete 16S rRNA gene sequencing and phylogenetic analysis. These gene sequences were analyzed by a variety of phylogenetic inference methods and found to be related to the newly established epsilon subdivision of the division Proteobacteria. Secondary structural model comparisons and comparisons of established signature base positions in the 16S rRNA confirmed the placement of the Alvinella clones in the epsilon subdivision of the Proteobacteria. PMID:7544093

Haddad, A; Camacho, F; Durand, P; Cary, S C

1995-01-01

257

Characterization of a Novel Spirochete Associated with the Hydrothermal Vent Polychaete Annelid, Alvinella pompejana  

PubMed Central

A highly integrated, morphologically diverse bacterial community is associated with the dorsal surface of Alvinella pompejana, a polychaetous annelid that inhabits active high-temperature deep-sea hydrothermal vent sites along the East Pacific Rise (EPR). Analysis of a previously prepared bacterial 16S ribosomal DNA (rDNA) library identified a spirochete most closely related to an endosymbiont of the oligochete Olavius loisae. This spirochete phylotype (spirochete A) comprised only 2.2% of the 16S rDNA clone library but appeared to be much more dominant when the same sample was analyzed by denaturing gradient gel electrophoresis (DGGE) and the terminal restriction fragment length polymorphism procedure (12 to 18%). PCR amplification of the community with spirochete-specific primers used in conjunction with DGGE analysis identified two spirochete phylotypes. The first spirochete was identical to spirochete A but was present in only one A. pompejana specimen. The second spirochete (spirochete B) was 84.5% similar to spirochete A and, more interestingly, was present in the epibiont communities of all of the A. pompejana specimens sampled throughout the geographic range of the worm (13N to 32S along the EPR). The sequence variation of the spirochete B phylotype was less than 3% for the range of A. pompejana specimens tested, suggesting that a single spirochete species was present in the A. pompejana epibiotic community. Additional analysis of the environments surrounding the worm revealed that spirochetes are a ubiquitous component of high-temperature vents and may play an important role in this unique ecosystem. PMID:11133434

Campbell, Barbara J.; Cary, S. Craig

2001-01-01

258

Phenotypic Variation and Fitness in a Metapopulation of Tubeworms (Ridgeia piscesae Jones) at Hydrothermal Vents  

PubMed Central

We examine the nature of variation in a hot vent tubeworm, Ridgeia piscesae, to determine how phenotypes are maintained and how reproductive potential is dictated by habitat. This foundation species at northeast Pacific hydrothermal sites 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 vent 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

Tunnicliffe, Verena; St. Germain, Candice; Hilrio, Ana

2014-01-01

259

Phenotypic variation and fitness in a metapopulation of tubeworms (Ridgeia piscesae Jones) at hydrothermal vents.  

PubMed

We examine the nature of variation in a hot vent tubeworm, Ridgeia piscesae, to determine how phenotypes are maintained and how reproductive potential is dictated by habitat. This foundation species at northeast Pacific hydrothermal sites 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 vent 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

Tunnicliffe, Verena; St Germain, Candice; Hilrio, Ana

2014-01-01

260

Biological communities at the Florida Escarpment resemble hydrothermal vent taxa  

SciTech Connect

Dense biological communities of large epifaunal taxa similar to those found along ridge crest vents at the East Pacific Rise were discovered in the abyssal Gulf of Mexico. These assemblages occur on a passive continental margin at the base of the Florida Escarpment, the interface between the relatively impermeable hemipelagic clays of the distal Mississippi Fan and the jointed Cretaceous limestone of Florida Platform. The fauna apparently is nourished by sulfide rich hypersaline waters seeping out at near ambient temperatures onto the sea floor. 16 references, 3 figures.

Paull, C.K.; Hecker, B.; Commeau, R.; Freeman-Lynde, R.P.; Neumann, C.; Corso, W.P.; Golubic, S.; Hook, J.E.; Sikes, E.; Curray, J.

1984-11-23

261

Biological communities at the Florida Escarpment resemble hydrothermal vent taxa  

USGS Publications Warehouse

Dense biological communities of large epifaunal taxa similar to those found along ridge crest vents 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.

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.

1984-01-01

262

Autonomous Underwater Vehicle(AUV) and Towed Vehicle Technologies for Under-Ice Hydrothermal Vent Studies at the Gakkel Ridge  

NASA Astrophysics Data System (ADS)

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 hydrothermal vents 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 hydrothermal vent site. 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 hydrothermal venting on the ultra-slow spreading Gakkel Ridge in the eastern Arctic basin.

Singh, H.; Akin, D.; Reves-Sohn, R.; Humphris, S.; Shank, T.; Edmonds, H.

2006-12-01

263

Biogeography revisited with network theory: retracing the history of hydrothermal vent communities.  

PubMed

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 hydrothermal vents, 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 hydrothermal vent 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

Moalic, Yann; Desbruyres, Daniel; Duarte, Carlos M; Rozenfeld, Alejandro F; Bachraty, Charleyne; Arnaud-Haond, Sophie

2012-01-01

264

Thermal adaptations in deep-sea hydrothermal vent and shallow-water shrimp  

NASA Astrophysics Data System (ADS)

The hydrothermal vent shrimp Mirocaris fortunata is commonly exposed to acute thermal gradients and rapid fluctuations in water temperature. The shallow-water shrimp Palaemonetes varians experiences less acute but similar magnitude fluctuations in its thermal regime. Acute respiratory response to temperature shock, and temperature preference was assessed for both species. Oxygen consumption rates were assessed across the natural temperature range reported for M. fortunata. Rates increased with temperature for both species. P. varians had a significantly higher rate of oxygen consumption than M. fortunata at all temperatures except 4 C. The rate of increase in oxygen consumption with increasing temperature was also significantly greater for P. varians. M. fortunata selected a significantly higher temperature than P. varians. Mirocaris fortunata maintains its metabolism at a more stable rate, which is likely an adaptation to acute changes in temperatures occurring at hydrothermal vents.

Smith, Felix; Brown, Alastair; Mestre, Nlia C.; Reed, Adam J.; Thatje, Sven

2013-08-01

265

Study on the high precision acoustic measurement techniques for determining temperature field around seafloor hydrothermal vent  

NASA Astrophysics Data System (ADS)

This paper presents the basis of acoustic method used for temperature field measurement of seafloor hydrothermal vent and two techniques of the parabolic interpolation and the bending compensation of propagation paths of acoustic signal are introduced. Experimental research is performed to exactly rebuild the temperature field around hot springs on the floor of Qiezishan Lake, Yunnan, China. The accuracy of the travel time estimation has been improved based on the aforementioned technique and method. At the same time, by comparison of the results of temperature field with different means, the max absolute error, the maximum relative error and the root mean square error are given. It shows that the technique and the method presented in the paper can be applied to the temperature field measurement detector around the seafloor hydrothermal vent. It also has a good accuracy.

Cai, Yong; Fan, Wei; Zhou, Yan; Fu, Xian-qiao; Fang, Hui; Jin, Tao

2012-12-01

266

Near-bottom water column anomalies associated with active hydrothermal venting at Aeolian arc volcanoes, Tyrrhenian Sea, Italy  

NASA Astrophysics Data System (ADS)

Hydrothermal 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 hydrothermal venting is less well known. A systematic water column survey in 2007 found helium isotope ratios indicative of active venting 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 venting 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. Venting 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 venting fluids with temperatures up to 5C 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 sites 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 vent fluids up to 54C 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 hydrothermal clay nontronite were found at actively venting 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 venting nearby, but not observed along the trackline of the ROV. Only the higher-temperature vent site 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.

Walker, S. L.; Carey, S.; Bell, K. L.; Baker, E. T.; Faure, K.; Rosi, M.; Marani, M.; Nomikou, P.

2012-12-01

267

Fe-oxidizing microbes are hydrothermal vent ecosystem engineers at the Loihi Seamount (Invited)  

NASA Astrophysics Data System (ADS)

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 hydrothermal vents, 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 site that has become a model for Fe oxidation in marine hydrothermal 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.

Chan, C. S.; McAllister, S.; Leavitt, A.; Emerson, D.; Moyer, C. L.; Glazer, B. T.

2013-12-01

268

Metaproteomic Analysis of a Chemosynthetic Hydrothermal Vent Community Reveals Insights into Key-Metabolic Processes  

NASA Astrophysics Data System (ADS)

In 2005 researchers at the Centre for Geobiology, University of Bergen, Norway, discovered two active vent fields at the southwestern Mohns Ridge in the Norwegian-Greenland Sea. The fields harbours both low-temperature iron deposits and high-temperature white smoker vents. Distinct microbial mats were abundantly present and located in close vicinity to the hydrothermal vent sites. Characteristics of the mat environment were steep physical and chemical gradients with temperatures ranging from 10C in the top layer to 90C 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 hydrothermal vent 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.

Steen, I.; Stokke, R.; Lanzen, A.; Pedersen, R.; vres, L.; Urich, T.

2010-12-01

269

Deep-sea hydrothermal vents: A new source of innovative bacterial exopolysaccharides of biotechnological interest?  

Microsoft Academic Search

Polysaccharides and, in particular, microbial polysaccharides represent a class of important products of growing interest\\u000a for many sectors of industry. Although many known marine bacteria produce exopolysaccharides (EPS), continuation in looking\\u000a for new polysaccharide-producing microorganisms is promising. Hydrothermal deep-sea vents could be a source of novel EPS as\\u000a indicated by the screening of a number of mesophilic heterotrophic bacteria recovered

J Guezennec

2002-01-01

270

First isolation of thermophilic aerobic non-sporulating heterotrophic bacteria from deep-sea hydrothermal vents  

Microsoft Academic Search

Thermophilic aerobic non-sporulating heterotrophic bacteria were isolated for the first time from deep-sea hydrothermal vents. Samples were taken at Snakepit (Mid-Atlantic Ridge) and Guaymas Basin (Gulf of California). Isolates consisting of pleomorphic rods, single cells or pairs, formed filaments of variable length, and grew at 70C or some up to 80C. They were halotolerant and unable to grow anaerobically, except

ViggThr Marteinsson; Jean-Louis Birrien; Jakob K. Kristjnsson; Daniel Prieur

1995-01-01

271

High incidence of halotolerant bacteria in Pacific hydrothermal-vent and pelagic environments  

Microsoft Academic Search

The abundance of halotolerant microorganisms in hydrothermal-vent 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 2024C. Based on these MPNs and direct counts with epifluorescence microscopy to enumerate the total microbial population, salt-tolerant microbes comprised from 28% of the total microbial community.

Jonathan Z Kaye; John A Baross

2000-01-01

272

Organisms of deep sea hydrothermal vents as a source for studying adaptation and evolution  

Microsoft Academic Search

It has been postulated that life originated in a similar environment to those of deep sea hydrothermal vents. These environments\\u000a are located along volcanic ridges and are characterized by extreme conditions such as unique physical properties (temperature,\\u000a pressure), chemical toxicity, and absence of photosynthesis. However, numerous living organisms have been discovered in these\\u000a hostile environments, including a variety of microorganisms

Zoran Minic

2009-01-01

273

Genetic diversity and demographic instability in Riftia pachyptila tubeworms from eastern Pacific hydrothermal vents  

Microsoft Academic Search

BackgroundDeep-sea hydrothermal vent animals occupy patchy and ephemeral habitats supported by chemosynthetic primary production. Volcanic\\u000a and tectonic activities controlling the turnover of these habitats contribute to demographic instability that erodes genetic\\u000a variation within and among colonies of these animals. We examined DNA sequences from one mitochondrial and three nuclear gene\\u000a loci to assess genetic diversity in the siboglinid tubeworm, Riftia

D Katharine Coykendall; Shannon B Johnson; Stephen A Karl; Richard A Lutz; Robert C Vrijenhoek

2011-01-01

274

First Active Hydrothermal Vent Fields Discovered at the Equatorial Southern East Pacific Rise  

NASA Astrophysics Data System (ADS)

The third leg of the 2008 Chinese DY115-20 expedition on board R/V Dayangyihao has successfully discovered, for the first time, active hydrothermal vent fields on the fast-spreading Southern East Pacific Rise (SEPR) near the equator. This expedition follows the work of a 2005 expedition by R/V Dayangyihao, during which water column turbidity anomalies were measured in the region. The newly discovered vent fields are located along a 22-km-long ridge segment of the SEPR at 102.655W/2.22S, 102.646W/2.152S, 102.619W/2.078S, and 102.62W/2.02S, respectively, as well as on an off-axial volcano near 102.456W/1.369S. A significant portion of the activity appears to be concentrated along the edges of a seafloor fissure system. Furthermore, water column turbidity anomalies were observed over off-axis volcanoes near 102.827W/2.084S and 102.58W/2.019S. Video footage of the vent fields and water column turbidity, temperature, and methane anomalies were recorded by a deep-towed integrated system consisting of video, still camera, CTD, and ADCP, and MAPR and METS sensors. Two active hydrothermal fields at 2.217S and 2.023S were then extensively photographed and surveyed using the autonomous underwater vehicle ABE of the Woods Hole Oceanographic Institution (WHOI). Four samples of hydrothermal chimneys were successfully obtained by a TV-guided grab in three locations, showing evidence of high-temperature hydrothermal venting.

Tao, C.; Lin, J.; Wu, G.; German, C. R.; Yoerger, D. R.; Chen, Y. J.; Guo, S.; Zeng, Z.; Han, X.; Zhou, N.; Li, J.; Xia, S.; Wang, H.; Ding, T.; Gao, S.; Qian, X.; Cui, R.; Zhou, J.; Ye, D.; Zhang8, Y.; Zhang, D.; Li, L.; Zhang, X.; Li, Y.; Wu, X.; Li, S.; He, Y.; Huang, W.; Wang, Y.; Wang, T.; Li, X.; Wang, K.; Gai, Y.; Science Party, D.; Baker, E. T.; Nakamura14, K.

2008-12-01

275

Pyrococcus abyssi sp. nov., a new hyperthermophilic archaeon isolated from a deep-sea hydrothermal vent  

Microsoft Academic Search

A novel, hyperthermophilic, anaerobic, sulfurmetabolizing archaeon was isolated from a fluid sample from recently discovered hydrothermal vents in the North Fiji basin (SW Pacific), at 2000 m depth. The new organism, strain GE5, is a gram-negative, highly motile coccus. It grows between 67 and 102C under atmospheric pressure, with an optimum at 96C (doubling time 33 min). The upper growth

Gal Erauso; Anna-Louise Reysenbach; Anne Godfroy; Jean-Roch Meunier; Byron Crump; Frdric Partensky; John A. Baross; Viggo Marteinsson; Georges Barbier; Norman R. Pace; Daniel Prieur

1993-01-01

276

An extremely thermophilic Methanococcus from a deep sea hydrothermal vent and its plasmid  

Microsoft Academic Search

An extremely thermophilic methanogen was isolated from a hydrothermal vent core sample from Guaymas Basin, Gulf of California, at a depth of 2003 m. The isolate, designated strain AG86, was a coccoid autotroph using H2-CO2 as energy and carbon source with a growth temperature range of 48 to 92C, optimum, 85C. AG86 required NaCl and Mg2+ and trace amounts of

Hongxue Zhao; Alvin G. Wood; Friedrich Widdel; Marvin P. Bryant

1988-01-01

277

Pyrococcus horikoshii sp. nov., a hyperthermophilic archaeon isolated from a hydrothermal vent at the Okinawa Trough  

Microsoft Academic Search

A hyperthermophilic, anaerobic archaeon was isolated from hydrothermal fluid samples obtained at the Okinawa Trough vents\\u000a in the NE Pacific Ocean, at a depth of 1395 m. The strain is obligately heterotrophic, and utilizes complex proteinaceous\\u000a media (peptone, tryptone, or yeast extract), or a 21-amino-acid mixture supplemented with vitamins, as growth substrates.\\u000a Sulfur greatly enhances growth. The cells are irregular

Juan M. Gonzlez; Yaeko Masuchi; Frank T. Robb; James W. Ammerman; Dennis L. Maeder; Miki Yanagibayashi; Jin Tamaoka; Chiaki Kato

1998-01-01

278

Molecular systematics of vestimentiferan tubeworms from hydrothermal vents and cold-water seeps  

Microsoft Academic Search

Vestimentiferan tubeworms inhabit sulfide-rich environments associated with deep-sea hydrothermal vents and cold-water seeps\\u000a at continental margins. Twelve species have been described, and several more await formal descriptions. As a group, these\\u000a worms are best known for their lack of a digestive system in adults and their dependence on endosymbiotic bacteria that supply\\u000a nutrients derived from chemoautotrophism. The taxonomic status of

M. B. Black; K. M. Halanych; P. A. Y. Maas; W. R. Hoeh; J. Hashimoto; D. Desbruyres; R. A. Lutz; R. C. Vrijenhoek

1997-01-01

279

Lithium isotopic systematics of hydrothermal vent fluids at the Main Endeavour Field, Northern Juan de Fuca Ridge  

Microsoft Academic Search

Vent fluids issuing from the Main Endeavour Field (MEF), Juan de Fuca Ridge, were analyzed for ?7Li to help constrain subseafloor hydrothermal alteration and phase separation processes. Magmatic activity prior to sampling of the fluids in 1999 enhanced heat and mass transfer, as indicated by the large scale, but temporary, changes in vent fluid chemistry. In particular, dissolved chloride concentrations

D. I. Foustoukos; R. H. James; M. E. Berndt; W SEYFRIEDJR

2004-01-01

280

Variations in deep-sea hydrothermal vent communities on the Mid-Atlantic Ridge near the Azores plateau  

Microsoft Academic Search

Near the Azores Triple Junction as the Azores Plateau is approached, the ridge axis becomes shallower; its depth decreases from ca. 2400m in the Rainbow vent field (3613?N) to ca. 850m in the Menez Gwen vent field (3735?N). In this area, extensive mussel beds of the mytilid Bathymodiolus azoricus dominate the hydrothermal vent fauna, along with populations of three shrimps

D. Desbruyres; M. Biscoito; J.-C. Caprais; A. Colao; T. Comtet; P. Crassous; Y. Fouquet; A. Khripounoff; N. Le Bris; K. Olu; R. Riso; P.-M. Sarradin; M. Segonzac; A. Vangriesheim

2001-01-01

281

The Sound Generated by Mid-Ocean Ridge Black Smoker Hydrothermal Vents  

PubMed Central

Hydrothermal flow through seafloor black smoker vents 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 vents 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. Vent 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

Crone, Timothy J.; Wilcock, William S.D.; Barclay, Andrew H.; Parsons, Jeffrey D.

2006-01-01

282

Geothermic Potential Assessment of hydrothermal vents of Township Barranca De Upia - Meta - Colombia  

NASA Astrophysics Data System (ADS)

Hydrothermal vents 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 hydrothermal vents 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 hydrothermal vents.

Chica, J.; Chicangana, G.; Eco Energy Research Group

2013-05-01

283

Proteomic responses to metal-induced oxidative stress in hydrothermal vent-living mussels, Bathymodiolus sp., on the Southwest Indian Ridge.  

PubMed

Bathymodiolin mussels are amongst the dominant fauna occupying hydrothermal vent 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 vent fauna. Bathymodiolus sp. were sampled from two newly-discovered vent sites 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 vent sites 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 vent sites and across a chemical gradient within the Knuckers Gaff vent site. Our findings highlight the importance of proteomic plasticity in successful adaptation to the spatially and temporally fluctuating chemical environments that are characteristic of hydrothermal vent habitats. PMID:24080408

Cole, Catherine; Coelho, Ana Varela; James, Rachael H; Connelly, Doug; Sheehan, David

2014-05-01

284

Extremely thermophilic fermentative archaebacteria of the genus desulfurococcus from deep-sea hydrothermal vents. Technical report  

SciTech Connect

Two strains of extremely thermophilic, anaerobic bacteria are described that are representative of isolates obtained from a variety of oceanic hydrothermal vent sites 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.

Jannasch, H.W.; Wirsen, C.O.; Molyneaux, S.J.; Langworthy, T.A.

1988-05-01

285

Tubeworm-associated communities at hydrothermal vents on the Juan de Fuca Ridge, northeast Pacific  

NASA Astrophysics Data System (ADS)

Hydrothermal vent communities on a mid-ocean ridge crest can be separated by large distances on separate segments. Heat sources, vent character, fluid chemistry and current patterns may differ markedly. This study examines whether vent community characteristics on three of the four southern segments of the Juan de Fuca Ridge are significantly different. Taxonomic composition and relative abundance of the fauna over 1 mm in size associated with vestimentiferan tubeworm bushes are examined from fifty-one collections. Among nearly 350,000 specimens, 37 taxa are recognized, most to species level. Another 14 taxa are meiofaunal in size classification. Species richness and selected diversity indicators are highest on Axial Volcano while animal density within the bushes does not differ significantly. Cluster analysis does not group collections by location, year of collection or vent temperature; collection substratumbasalt or sulphidemay influence clustering. The architecture of the tubes of tubeworm bushes appears to affect the numbers of species present and the resultant clusters. The tightly interwoven, knotted Ridgeia piscesae tubes found on Axial host twice as many species as tubeworm bushes with a less complex structure. Four species dominate most of the collections: two gastropods ( Lepetodrilus fucensis and Depressigyra globulus) and two polychaetes ( Paralvinella pandorae and Amphisamytha galapagensis). Other vent species are low in abundance (<1% relative abundance) and patchy in distribution. Four collections with no visible flow had markedly different assemblages representing a transition state from vent assemblages to normal deep-sea fauna. There are differences in community structure among the segments, but the causes for these differences are unclear. Higher diversity on Axial Volcano may be supported by a greater time of sustained venting, a larger venting area, water circulation contained within the caldera, or flow conditions that sponsor growth of more complex habitat.

Tsurumi, Maia; Tunnicliffe, Verena

2003-05-01

286

Sound field near hydrothermal vents on Axial Seamount, Juan de Fuca Ridge. Technical report  

SciTech Connect

High-quality acoustic noise measurements were obtained by two hydrophones located 3 m and 40 m from an active hydrothermal vent on Axial Seamount, Juan de Fuca Ridge, in an effort to determine the feasibility of monitoring hydrothermal vent 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 vent signals was hampered by unexpected spatial nonstationarity due to the shadowing effects of the calders wall. No continuous vent 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).

Little, S.A.; Stolzenbach, K.D.; Purdy, G.M.

1990-08-10

287

Quantifying metabolic rates in submarine hydrothermal vent chimneys: A reaction transport model  

NASA Astrophysics Data System (ADS)

The fluids emanating from active submarine hydrothermal vent 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, hydrothermal fluid, minerals and microorganisms inside chimney walls, none provide a fully integrated approach to quantifying the biogeochemistry of these hydrothermal systems. In an effort to remedy this, a fully coupled biogeochemical reaction transport model of a hydrothermal vent 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 vent 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 hydrothermal systems and can be used to better understand the role of microbial activity in the deep subsurface.

LaRowe, D.; Dale, A.; Aguilera, D.; Amend, J. P.; Regnier, P.

2012-12-01

288

An origin-of-life reactor to simulate alkaline hydrothermal vents.  

PubMed

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 hydrothermal systems sustain natural proton gradients across the thin inorganic barriers of interconnected micropores within deep-sea vents. 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 vent 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 hydrothermal vents, allowing investigation of the possibility that abiotic vent 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 vent 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 vent conditions. PMID:25428684

Herschy, Barry; Whicher, Alexandra; Camprubi, Eloi; Watson, Cameron; Dartnell, Lewis; Ward, John; Evans, Julian R G; Lane, Nick

2014-12-01

289

Formation of Zn- and Fe-sulfides near hydrothermal vents at the Eastern Lau Spreading Center: implications for sulfide bioavailability to chemoautotrophs  

PubMed Central

Background The speciation of dissolved sulfide in the water immediately surrounding deep-ocean hydrothermal vents 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 hydrothermal vent fields at the Eastern Lau Spreading Center (ELSC) in the southern Pacific Ocean. Compared to other well-studied hydrothermal 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 (< 50C) and high-temperature (> 250C) vent fluids were collected from four field sites along the ELSC ridge axis. Total and filtered Zn and Fe concentrations were quantified in the vent fluid samples using voltammetric and spectrometric analyses. The results indicated north-to-south variability in vent fluid composition. In the high temperature vent fluids, the ratio of total Fe to total Zn varied from 39 at Kilo Moana, the most northern site, to less than 7 at the other three sites. 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 vent 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 vent habitats, particularly at the southern sites where Zn concentrations increase relative to Fe. As the hydrothermal 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

Hsu-Kim, Heileen; Mullaugh, Katherine M; Tsang, Jeffrey J; Yucel, Mustafa; Luther, George W

2008-01-01

290

Magnitude and variance of near-bottom horizontal heat flux at the Main Endeavour hydrothermal vent field  

Microsoft Academic Search

We characterize hydrothermal plumes and hydrography within the axial valley of the Endeavour segment (Juan de Fuca ridge, northeast Pacific) using data from an autonomous underwater vehicle, a lowered CTD, and two current meter moorings. Our survey of the Main Endeavour hydrothermal vent field (MEF) shows hydrographic variability on scales as short as ?20 m and ?10 min. Within the

Scott R. Veirs; Russell E. McDuff; Frederick R. Stahr

2006-01-01

291

Long-Lived Serpentinization and Carbonate Precipitation at the Lost City Hydrothermal Vent Field  

NASA Astrophysics Data System (ADS)

The discovery of spectacular, actively venting carbonate chimneys at the Lost City hydrothermal vent field (LCHF) on the Atlantis Massif (MAR 30oN) has stimulated great interest in the role of serpentinization in driving hydrothermal 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 hydrothermal phases include the LCHF chimneys and carbonate precipitates on outcrop surfaces, in cavities, and as growths protruding from fissures that are locally venting fluids. Sr-, C- and O-isotope analyses and radiocarbon age-dating indicate that this system is the integrated effect of tectonic activity, serpentinization, and hydrothermal 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 hydrothermal fluids. Analyses of separated fractions of sedimentary and hydrothermal components define a sedimentary end-member composition of ? 13C = 1.3 +/- 0.3 and ? 18O = 1.5 +/- 0.5 (VPDB) and a hydrothermal end-member composition of ? 13C = 3.3 and ? 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 ? 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 hydrothermal activity for tens of thousands of years.

Frueh-Green, G. L.; Kelley, D. S.; Karson, J. A.; Bernasconi, S. M.; Proskurowski, G.; Ludwig, K. A.

2003-12-01

292

Evidence for Pulsed Hydrothermal Venting from Young Abyssal Hills on the EPR Flank Suggests Frequent Seismic Pumping of Ridge Flank Fluid Flow  

NASA Astrophysics Data System (ADS)

Although measured heat flow suggests that 40-50% of oceanic hydrothermal heat and fluid flux is from young (0.1-5 Ma) abyssal hill terrain on MOR flanks, hydrothermal vents in this setting rarely have been found. On the EPR flanks, seafloor evidence of venting from abyssal hills has been discovered recently at two sites: on 0.1 Ma seafloor at 10 20'N, 103 33.2'W ("Tevnia Site") and on 0.5 Ma seafloor at 9 27'N, 104 32.3'W ("Macrobes Site"). Manifestations of venting at these sites include: fault scarp hydrothermal mineralization and macrofauna; fault scarp flocculations containing hyperthermophilic microbes; and hilltop sediment mounds and craters possibly created by fluid "blow-outs." Hydrothermal deposits recovered at the 0.1 Ma "Tevnia Site" are fault breccias that record many episodes of brecciation followed by hydrothermal cementation (Benjamin et al., this session). Tubeworm casings, live crabs, and "dandelions" observed at this site indicate that the most recent episode of venting was active during, or shortly before, this site was visited with Alvin in 1994. To create the 200 m-high axis-facing fault scarp at Tevnia Site 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 hydrothermal flow on a very frequent basis. In addition, close proximity to Clipperton Transform may subject Tevnia Site 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 Site samples, and biological evidence for recent venting at the site, are evidence that hydrothermal 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 Site" are associated with chalcopyrite particles (Ehrhardt et al., this session). These observations indicate recent, transient venting 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 sites points to seismic pumping of EPR abyssal hill hydrothermal pulses every few years-to-decades. These frequent hydrothermal pulses may be important in sustaining ridge flank biota. Monitoring of EPR abyssal hill fault scarps is needed to test these ideas.

Haymon, R. M.; MacDonald, K. C.; Benjamin, S. B.; Ehrhardt, C. J.

2004-12-01

293

Diffuse flow environments within basalt- and sediment-based hydrothermal vent ecosystems harbor specialized microbial communities.  

PubMed

Hydrothermal vents 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 vents at a basalt-based hydrothermal system along the East Pacific Rise (EPR) and a sediment-based hydrothermal 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 hydrothermal 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 hydrothermal 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 hydrothermal diffuse flow environments. PMID:23898323

Campbell, Barbara J; Polson, Shawn W; Zeigler Allen, Lisa; Williamson, Shannon J; Lee, Charles K; Wommack, K Eric; Cary, S Craig

2013-01-01

294

Diffuse flow environments within basalt- and sediment-based hydrothermal vent ecosystems harbor specialized microbial communities  

PubMed Central

Hydrothermal vents 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 vents at a basalt-based hydrothermal system along the East Pacific Rise (EPR) and a sediment-based hydrothermal 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 hydrothermal 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 hydrothermal 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 hydrothermal diffuse flow environments. PMID:23898323

Campbell, Barbara J.; Polson, Shawn W.; Zeigler Allen, Lisa; Williamson, Shannon J.; Lee, Charles K.; Wommack, K. Eric; Cary, S. Craig

2013-01-01

295

Arsenic speciation in food chains from mid-Atlantic hydrothermal vents  

PubMed Central

Arsenic concentration and speciation were determined in benthic fauna collected from the Mid-Atlantic Ridge hydrothermal vents. The shrimp species, Rimicaris exoculata, the vent chimney-dwelling mussel, Bathymodiolus azoricus, Branchipolynoe seepensis, a commensal worm of B. azoricus, and the gastropod Peltospira smaragdina showed variations in As concentration and in stable isotope (?13C and ?15N) signature between species, suggesting different sources of As uptake. Arsenic speciation showed arsenobetaine to be the dominant species in R. exoculata, whereas in B. azoricus and B. seepensis arsenosugars were most abundant, although arsenobetaine, dimethylarsinate, and inorganic arsenic were also observed, along with several unidentified species. Scrape samples from outside the vent chimneys, covered with microbial mat, which is a presumed food source for many vent 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 vent origin, suggests that organic arsenicals can occur in a food web without algae or other photosynthetic life. PMID:23741175

Taylor, Vivien F.; Jackson, Brian P.; Siegfried, Matthew; Navratilova, Jana; Francesconi, Kevin A.; Kirshtein, Julie; Voytek, Mary

2012-01-01

296

Impacts of anthropogenic disturbances at deep-sea hydrothermal vent ecosystems: a review.  

PubMed

Deep-sea hydrothermal-vent 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 vent environments, and vent-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 vents are considered. Mining is currently the only anthropogenic activity projected to have a major impact on vent 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

Van Dover, Cindy Lee

2014-12-01

297

Arsenic speciation in food chains from mid-Atlantic hydrothermal vents  

USGS Publications Warehouse

Arsenic concentration and speciation were determined in benthic fauna collected from the Mid-Atlantic Ridge hydrothermal vents. The shrimp species, Rimicaris exoculata, the vent chimney-dwelling mussel, Bathymodiolus azoricus, Branchipolynoe seepensis, a commensal worm of B. azoricus and the gastropod Peltospira smaragdina showed variations in As concentration and in stable isotope (?13C and ?15N) signature between species, suggesting different sources of As uptake. Arsenic speciation showed arsenobetaine to be the dominant species in R. exoculata, whereas in B. azoricus and B. seepensis arsenosugars were most abundant, although arsenobetaine, dimethylarsinate and inorganic arsenic were also observed, along with several unidentified species. Scrape samples from outside the vent chimneys covered with microbial mat, which is a presumed food source for many vent 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 vent origin, suggests that organic arsenicals can occur in a foodweb without algae or other photosynthetic life.

Taylor, Vivien F.; Jackson, Brian P.; Siegfried, Matthew R.; Navratilova, Jana; Francesconi, Kevin A.; Kirshtein, Julie; Voytek, Mary

2012-01-01

298

Sulfide binding is mediated by zinc ions discovered in the crystal structure of a hydrothermal vent tubeworm hemoglobin  

PubMed Central

Key to the remarkable ability of vestimentiferan tubeworms to thrive in the harsh conditions of hydrothermal vents are hemoglobins that permit the sequestration and delivery of hydrogen sulfide and oxygen to chemoautotrophic bacteria. Here, we demonstrate that zinc ions, not free cysteine residues, bind sulfide in vestimentiferan hemoglobins. The crystal structure of the C1 hemoglobin from the hydrothermal vent tubeworm Riftia pachyptila has been determined to 3.15 and revealed the unexpected presence of 12 tightly bound Zn2+ ions near the threefold axes of this D3 symmetric hollow sphere. Chelation experiments on R. pachyptila whole-coelomic fluid and purified hemoglobins reveal a role for Zn2+ ions in sulfide binding. Free cysteine residues, previously proposed as sulfide-binding sites in vestimentiferan hemoglobins, are found buried in surprisingly hydrophobic pockets below the surface of the R. pachyptila C1 molecule, suggesting that access of these residues to environmental sulfide is restricted. Attempts to reduce the sulfide-binding capacities of R. pachyptila hemoglobins by addition of a thiol inhibitor were also unsuccessful. These findings challenge the currently accepted paradigm of annelid hemoglobin evolution and adaptation to reducing environments. PMID:15710902

Flores, Jason F.; Fisher, Charles R.; Carney, Susan L.; Green, Brian N.; Freytag, John K.; Schaeffer, Stephen W.; Royer, William E.

2005-01-01

299

Bioavailability, Bioaccumulation and Biotransformation of arsenic in coral reef organisms surrounding an arsenic-rich marine shallow-water hydrothermal vent system in the coastal waters of Ambitle Island, Papua New Guinea  

NASA Astrophysics Data System (ADS)

Marine shallow-water hydrothermal 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 hydrothermally-derived arsenic into several coral reef organisms from the arsenic-rich marine shallow-water hydrothermal system of Tutum Bay, Ambitle Island, in northeastern Papua New Guinea. Hydrothermal venting provided bioavailable As by two major pathways throughout Tutum Bay: 1) easily-exchangeable As from hydrothermally influenced sediments to as far away as 200 m from focused venting, 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 hydrothermal area each displayed distinctly higher (up to 20 times) total arsenic compared to the control site, with increasing trends while approaching focused hydrothermal venting. 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 site versus the hydrothermal site, although the concentrations were much higher. Elevated concentrations of DMA and cationic forms of arsenic, most likely AB, in Clavularia, both from the control site and from the hydrothermal area suggest its metabolic pathway is not altered due to hydrothermal activity, and is similar to other marine organisms. Arsenic speciation patterns in Polycarpa were also similar for both sites, 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 hydrothermal system suggest this organism is not efficient at methylating inorganic arsenic.

Pichler, T.; Wallschlger, D.; Price, R. E.

2009-12-01

300

Evidence of sub-vent biosphere: enzymatic activities in 308 C deep-sea hydrothermal systems at Suiyo seamount, Izu Bonin Arc, Western Pacific Ocean  

NASA Astrophysics Data System (ADS)

A high-temperature deep-sea hydrothermal system related to dacitic arc-volcanism was drilled using a tethered, submarine rock-drill system as a part of the Archaean Park Project. The benthic multi-coring system (BMS) employed allowed for direct sampling of microorganisms, rocks and fluids beneath hydrothermal vents. The samples examined in this study were from sites APSK 05 and APSK 07 on the Suiyo Seamount of the Izu-Bonin Arc in the Pacific Ocean. Based on the vertical distribution of samples derived from this vigorous sub-vent environment, a model of deep-sea subterranean chemistry and biology was determined detailing optimal microbial activities. Deep-sea hydrothermal sub-vent core samples of dacitic arc-volcanism obtained at the Suiyo Seamount, Izu-Bonin Arc, Western Pacific Ocean were analyzed for acid and alkaline phosphatase enzymatic activities. Useful biomarkers of acid phosphatase (ACP) and alkaline phosphatase (ALP) enzymatic activities were positively correlated against each other and was greatest at the partial middle core sequences; ACP and ALP activities determined were as high as 5.10 and 6.80 nmol/min/g rock, respectively. Biochemical indicators of ACP and ALP were consistent with the origin of biogenic amino acids occupied in the sub-vent region and microbial cell number in the fluid. The significant enzymatic activities demonstrated in this study provides crucial evidence that sub-vent regions represent part of the previously unknown extreme-environment biosphere, extending the known subterranean habitable spaces of, for example, extremophilic microbes. This boring trial was first example of discharging high temperature hydrothermal activities at the frontal arc volcanoes.

Takano, Yoshinori; Edazawa, Yae; Kobayashi, Kensei; Urabe, Tetsuro; Marumo, Katsumi

2005-01-01

301

Molecular Diversity and Activity of Methanogens in the Subseafloor at Deep-Sea Hydrothermal Vents of the Pacific Ocean (Invited)  

NASA Astrophysics Data System (ADS)

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 hydrothermal vents. 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 vent fluids from the Endeavour Segment R2K ISS site, as well as Axial Seamount and volcanoes of the Mariana Arc. Geochemical data from hot and adjacent warm diffuse vent 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 vent sites, hydrogen concentrations were too low to support hydrogenotrophic methanogensis directly and only one diffuse site, 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 vents have strong chemical indicators of methanogenesis. Methanogenic communities were detected at 3 sites 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 site, including mesophiles and hyper/thermophiles, but that some methanogens recovered from Marker 113 are surviving at low or sub-optimal hydrogen levels. Vent 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 site. 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 vent 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 hydrothermal systems from mantle to microbes.

Huber, J. A.; Merkel, A.; Holden, J. F.; Lilley, M. D.; Butterfield, D. A.

2009-12-01

302

Characterizing the plasticity of nitrogen metabolism by the host and symbionts of the hydrothermal vent chemoautotrophic symbioses Ridgeia piscesae.  

PubMed

Chemoautotrophic symbionts of deep sea hydrothermal vent tubeworms are known to provide their hosts with all their primary nutrition. While studies have examined how chemoautotrophic symbionts provide the association with nitrogen, fewer have examined if symbiont nitrogen metabolism varies as a function of environmental conditions. Ridgeia piscesae tubeworms flourish at Northeastern Pacific vents, occupy a range of microhabitats, and exhibit a high degree of morphological plasticity [e.g. long-skinny (LS) and short-fat (SF) phenotypes] that may relate to environmental conditions. This plasticity affords an opportunity to examine whether symbiont nitrogen metabolism varies among host phenotypes. LS and SF R.piscesae were recovered from the Axial and Main Endeavour Field hydrothermal vents. Nitrate and ammonium were quantified in Ridgeia blood, and the expression of key nitrogen metabolism genes, as well as stable nitrogen isotope ratios, was quantified in host branchial plume and symbiont-containing tissues. Nitrate and ammonium were abundant in the blood of both phenotypes though environmental ammonium concentrations were, paradoxically, lowest among individuals with the highest blood ammonium. Assimilatory nitrate reductase transcripts were always below detection, though in both LS and SF R.piscesae symbionts, we observed elevated expression of dissimilatory nitrate reductase genes, as well as symbiont and host ammonium assimilation genes. Site-specific differences in expression, along with tissue stable isotope analyses, suggest that LS and SF Ridgeia symbionts are engaged in both dissimilatory nitrate reduction and ammonia assimilation to varying degrees. As such, it appears that environmental conditions -not host phenotype-primarily dictates symbiont nitrogen metabolism. PMID:24237389

Liao, Li; Wankel, Scott D; Wu, Min; Cavanaugh, Colleen M; Girguis, Peter R

2014-03-01

303

Biogeochemistry of hydrothermal vent mussel communities: the deep-sea analogue to the intertidal zone  

NASA Astrophysics Data System (ADS)

Continuous measurements of sulfide, silicate and temperature were made in situ from the submersible Alvin in the Rose Garden and New Vent hydrothermal 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 vent mussel Bathymodiolus thermophilus in the Rose Garden. Dense clusters of B. thermophilus can disperse the hydrothermal 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 vent community. The mussel can tolerate these wide ranges in condition because of its ability to accept long periods of anoxia and to filter feed.

Johnson, Kenneth S.; Childress, James J.; Beehler, Carl L.; Sakamoto, Carole M.

1994-07-01

304

Biogeography and ecology of the rare and abundant microbial lineages in deep-sea hydrothermal vents.  

PubMed

Environmental gradients generate countless ecological niches in deep-sea hydrothermal vent systems, which foster diverse microbial communities. The majority of distinct microbial lineages in these communities occur in very low abundance. However, the ecological role and distribution of rare and abundant lineages, particularly in deep, hot subsurface environments, remain unclear. Here, we use 16S rRNA tag sequencing to describe biogeographic patterning and microbial community structure of both rare and abundant archaea and bacteria in hydrothermal vent systems. We show that while rare archaeal lineages and almost all bacterial lineages displayed geographically restricted community structuring patterns, the abundant lineages of archaeal communities displayed a much more cosmopolitan distribution. Finally, analysis of one high-volume, high-temperature fluid sample representative of the deep hot biosphere described a unique microbial community that differed from microbial populations in diffuse flow fluid or sulfide samples, yet the rare thermophilic archaeal groups showed similarities to those that occur in sulfides. These results suggest that while most archaeal and bacterial lineages in vents are rare and display a highly regional distribution, a small percentage of lineages, particularly within the archaeal domain, are successful at widespread dispersal and colonization. PMID:25764538

Anderson, Rika E; Sogin, Mitchell L; Baross, John A

2015-01-01

305

Thermophilic and hyperthermophilic microorganisms in 3^30C hydrothermal uids following a deep-sea volcanic eruption  

E-print Network

³C diffuse hydrothermal fluids at the CoAxial segment deep-sea hydrothermal vent site 3 months after: Thermophile; Hyperthermophile; Archaea; Subsurface biosphere; Hydrothermal vent; Volcanic eruption 1£oor thermal and chemical gradients associated with deep-sea vents for growth. A sample of hydrothermal sul

Holden, James F.

306

Hydrothermal venting along Earth's fastest spreading center: East Pacific Rise, 27.5-32.3  

NASA Astrophysics Data System (ADS)

During March/April 1998 we conducted detailed mapping and sampling of hydrothermal plumes along six segments of Earth's fasting spreading mid-ocean ridge, 27.5-32.3S on the East Pacific Rise. We compared the distribution and chemistry of hydrothermal 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. Hydrothermal plumes overlaid ~60% of the length of superfast (>130 km/Myr) spreading axis surveyed and defined at least 14 separate vent fields. We observed no plumes over the slower spreading propagating segments. Finer-scale variations in the magmatic budget also correlated with hydrothermal 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 hydrothermal plume. Plume chemistry mostly reflected discharge from mature vent fields apparently unperturbed by magmatic activity within the last few years. Plume samples with high volatile/metal ratios, generally indicating recent seafloor volcanism, were scarce. Along-axis trends in both volatile (3He; CH4; ?pH, a proxy for CO2; and particulate S) and nonvolatile (Fe, Mn) species showed a first-order agreement with the trend of ridge inflation. Nevertheless, a broad correspondence between the concentration of volatile species in plumes and geological proxies of magma supply identifies a pervasive magmatic imprint on this superfast spreading group of ridge segments.

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.

2002-07-01

307

Hydrogen-limited growth of hyperthermophilic methanogens at deep-sea hydrothermal vents  

PubMed Central

Microbial productivity at hydrothermal vents is among the highest found anywhere in the deep ocean, but constraints on microbial growth and metabolism at vents 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 hydrothermal fluids from Axial Volcano and Endeavour Segment in the northeastern Pacific Ocean. Two Methanocaldococcus strains from Axial and Methanocaldococcus jannaschii showed similar Monod growth kinetics when grown in a bioreactor at varying H2 concentrations. Their H2 half-saturation value was 66 ?M, and growth ceased below 1723 ?M H2, 10-fold lower than previously predicted. By comparison, measured H2 and CH4 concentrations in fluids suggest that there was generally sufficient H2 for Methanocaldococcus growth at Axial but not at Endeavour. Fluids from one vent 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 ?0.26% 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 vents and highlight the need for coupled laboratory and field measurements to constrain microbial distribution and biogeochemical impacts in the deep sea. PMID:22869718

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.

2012-01-01

308

Complete mitochondrial genome of the hydrothermal vent tubeworm, Ridgeia piscesae (Polychaeta, Siboglinidae).  

PubMed

Abstract The complete mitochondrial genome of Ridgeia piscesae (Polychaeta, Siboglinidae), one of the dominant taxa in deep-sea hydrothermal vents, 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

Jun, Jumin; Won, Yong-Jin; Vrijenhoek, Robert C

2014-07-11

309

Fossils of hydrothermal vent worms from Cretaceous sulfide ores of the Samail ophiolite, Oman  

USGS Publications Warehouse

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 hydrothermal vent similar to modern hot springs on the East Pacific Rise and the Juan de Fuca Ridge.

Haymon, R.M.; Koski, R.A.; Sinclair, C.

1984-01-01

310

The possible role of hydrothermal vents in chemical evolution: Succinic acid radiolysis and thermolysis  

NASA Astrophysics Data System (ADS)

In this research, the behavior under a high radiation field or high temperature of succinic acid, a dicarboxylic acid clue in metabolic routes, is studied. For this purpose, the molecule was irradiated with gamma rays in oxygen-free aqueous solutions, and the thermal decomposition was studied in a static system at temperatures up to 90 C, simulating a white hydrothermal vent. Our results indicate that a succinic acid is a relatively stable compound under irradiation. The gamma radiolysis yields carbon dioxide and di- and tricarboxylic acids such as malonic, carboxysuccinic, and citric acids. The main products obtained by the thermal treatment were CO2 and propionic acid.

Cruz-Castaeda, J.; Coln-Garca, M.; Negrn-Mendoza, A.

2014-07-01

311

Along-axis hydrothermal flow at the axis of slow spreading Mid-Ocean Ridges: Insights from numerical models of the Lucky Strike vent field (MAR)  

NASA Astrophysics Data System (ADS)

processes and efficiency of hydrothermal heat extraction along the axis of mid-ocean ridges are controlled by lithospheric thermal and permeability structures. Hydrothermal circulation models based on the structure of fast and intermediate spreading ridges predict that hydrothermal cell organization and vent site distribution are primarily controlled by the thermodynamics of high-temperature mid-ocean ridge hydrothermal fluids. Using recent constraints on shallow structure at the slow spreading Lucky Strike segment along the Mid-Atlantic Ridge, we present a physical model of hydrothermal cooling that incorporates the specificities of a magma-rich slow spreading environment. Using three-dimensional numerical models, we show that, in contrast to the aforementioned models, the subsurface flow at Lucky Strike is primarily controlled by across-axis permeability variations. Models with across-axis permeability gradients produce along-axis oriented hydrothermal cells and an alternating pattern of heat extraction highs and lows that match the distribution of microseismic clusters recorded at the Lucky Strike axial volcano. The flow is also influenced by temperature gradients at the base of the permeable hydrothermal domain. Although our models are based on the structure and seismicity of the Lucky Strike segment, across-axis permeability gradients are also likely to occur at faster spreading ridges and these results may also have important implications for the cooling of young crust at fast and intermediate spreading centers.

Fontaine, Fabrice J.; Cannat, Mathilde; Escartin, Javier; Crawford, Wayne C.

2014-07-01

312

Investigation of extractable organic compounds in deep-sea hydrothermal vent fluids along the Mid-Atlantic Ridge  

NASA Astrophysics Data System (ADS)

The possibility that deep-sea hydrothermal vents 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 vent 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 hydrothermal fluids was assessed at three sites 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 sites within the Lucky Strike, Rainbow, and Lost City hydrothermal 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 C12 n-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 hydrothermal chimney proximal to the site of fluid discharge or are transported from deeper within the system. Hydrothermal 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 hydrothermal system. While there is considerable evidence that Rainbow and Lost City vent 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.

McCollom, Thomas M.; Seewald, Jeffrey S.; German, Christopher R.

2015-05-01

313

Physiological characteristics of Thiomicrospira sp. strain L-12 isolated from deep-sea hydrothermal vents  

SciTech Connect

Growth of the obligately chemolithotrophic Thiomicrospira sp. strain L-12, isolated from a hydrothermal vent 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 hydrothermal environment.

Ruby, E.G.; Jannasch, H.W.

1982-01-01

314

Population ecology of the tonguefish Symphurus thermophilus (Pisces; Pleuronectiformes; Cynoglossidae) at sulphur-rich hydrothermal vents on volcanoes of the northern Mariana Arc  

NASA Astrophysics Data System (ADS)

Flatfish are a major component of the hydrothermal vent community on three seamounts of the northern Mariana Volcanic Arc in the northwest Pacific. Nikko, Kasuga-2 and Daikoku seamounts host vent fields between 375 and 480 m depth where high temperature vents release molten sulphur. The small cynoglossid tonguefish, Symphurus thermophilus Munroe and Hashimoto, is ubiquitous in all vent 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 vents 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 vent sites. Limited genetic data suggest that larval exchange probably occurs among sites 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 hydrothermalism.

Tunnicliffe, Verena; Tyler, Jennifer; Dower, John F.

2013-08-01

315

Microbially-Mediated Sulfur Oxidation in Diffuse Hydrothermal Vent Fluids at Axial Seamount, Juan de Fuca Ridge  

NASA Astrophysics Data System (ADS)

Diffusely venting hydrothermal fluids can act as a window to the subseafloor microbial environment, where chemically-reduced hydrothermal fluids mixing with oxygenated seawater in the shallow crust creates chemical disequilibria that chemotrophic microorganisms can exploit for energy gain. At Axial Seamount, an active deep-sea volcano located on the Juan de Fuca Ridge, sulfide concentrations have been measured as high as 5770 ?M, and sulfide oxidation is quantitatively the most important chemical energy source for microbial metabolism. In addition, studies of microbial population structure indicate that diffuse fluids at Axial are dominated by putative sulfur- and sulfide-oxidizing bacteria belonging to the Epsilonproteobacteria. To further study this important microbial process, we surveyed diffuse vent 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 40C and lower the potential for sulfide oxidation, so we identified six sites of different temperatures, two each in the low (< 30C), medium (~30C), and high temperature (30 - 50C) range. The low temperature sites 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 sites were positive for soxB in the DNA fraction. Bulk RNA was also extracted from the same sites 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 sites at Axial following the recent 2011 eruption, as well as fluid samples collected from new snowblower vents believed to be rich in sulfide-oxidizing bacteria.

Akerman, N. H.; Butterfield, D. A.; Huber, J. A.

2011-12-01

316

Isotopic Approaches to Allying Productivity and Sulfur Metabolism in Three Symbiotic Hydrothermal Vent Molluscs  

NASA Astrophysics Data System (ADS)

Symbioses between animals and chemosynthetic bacteria predominate at hydrothermal vents. 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 vents 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 vent-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 vent-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 vent 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.

Beinart, R.; Gartman, A.; Sanders, J. G.; Luther, G. W.; Girguis, P. R.

2012-12-01

317

Formation of Zn and Fe-sulfides near hydrothermal vents at the Eastern Lau Spreading Center: implications for sulfide bioavailability to chemoautotrophs  

Microsoft Academic Search

BACKGROUND: The speciation of dissolved sulfide in the water immediately surrounding deep-ocean hydrothermal vents 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 hydrothermal vent fields at the Eastern Lau Spreading Center (ELSC) in

Heileen Hsu-Kim; Katherine M Mullaugh; Jeffrey J Tsang; Mustafa Yucel; George W Luther

2008-01-01

318

Phylogenetic characterization of the bacterial assemblage associated with mucous secretions of the hydrothermal vent polychaete Paralvinella palmiformis  

Microsoft Academic Search

As part of an ongoing examination of microbial diversity associated with hydrothermal vent polychaetes of the family Alvinellidae, we undertook a culture-independent molecular analysis of the bacterial assemblage associated with mucous secretions of the Northeastern Pacific vent polychaete Paralvinella palmiformis. Using a molecular 16S rDNA-based phylogenetic approach, clone libraries were constructed from two samples collected from active sulfide edifices in

Karine Alain; Michel Olagnon; Daniel Desbruyres; Georges Barbier; S. Kim Juniper; Jol Qurellou; Marie-Anne Cambon-Bonavita

2002-01-01

319

Phylogenetic Diversity of the Bacterial Community from a Microbial Mat at an Active, Hydrothermal Vent System, Loihi Seamount, Hawaii  

Microsoft Academic Search

The phylogenetic diversity of small-subunit rRNA genes associated with the domainBacteriawas examined (by using previously defined operational taxonomic units (C. L. Moyer, F. C. Dobbs, and D. M. Karl, Appl. Environ. Microbiol. 60:871-879, 1994); those for Pele's VentsBacteriaare hereafter abbreviated PVBOTUs) with samples from a microbial mat at an active, deep-sea hydrothermal vent system. A cluster of phylogeneti- cally related

CRAIG L. MOYER; FRED C. DOBBS; ANDDAVID M. KARL

1995-01-01

320

The resistance to ionizing radiation of hyperthermophilic archaea isolated from deep-sea hydrothermal vents  

NASA Astrophysics Data System (ADS)

In this paper we present many results on radioresistance of hyperthermophilic archaeon isolated from deep-sea hydrothermal vents. Effects of gamma (?) irradiation was first tested with Pyrococcus abyssi and showed that this micro-organism did not show any loss of viability until 2 kGy of ?-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 hydrothermal vents 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.

Jolivet, E.; L'Haridon, S.; Corre, E.; Grard, E.; Myllykallio, H.; Forterre, P.; Prieur, D.

2001-08-01

321

High contents of hypotaurine and thiotaurine in hydrothermal-vent gastropods without thiotrophic endosymbionts.  

PubMed

Invertebrates at hydrothermal vents and cold seeps must cope with high levels of toxic H2S. In addition, these and all marine invertebrates must balance internal osmotic pressure with that of the ocean. Cells usually do so with organic osmolytes, primarily free amino acids (e.g., taurine, glycine) and methylamines (e.g., betaine). At vents and seeps, clams, mussels, and vestimentiferans with thiotrophic endosymbionts have high levels of hypotaurine and thiotaurine (a product of hypotaurine and HS-). These serve as osmolytes but their primary function may be to transport and/or detoxify sulfide; indeed, thiotaurine has been proposed to be a marker of thiotrophic symbiosis. To test this, we analyzed Depressigyra globulus snails and Lepetodrilus fucensis limpets from Juan de Fuca Ridge vents (1,530 m). Neither has endosymbionts, though the latter has thiotrophic ectosymbionts. Some specimens were rapidly frozen, while other live ones were kept in laboratory chambers, some with and others without sulfide. Non-vent gastropods from a variety of depths (2-3,000 m) were also collected. Tissues were analyzed for major osmolytes and taurine derivatives. The dominant osmolytes of non-vent snails were betaine in all species, and either taurine in shallow-living species or scyllo-inositol, glycerophosphorylcholine, and other amino acids in deep-sea species. In contrast, the dominant osmolytes were hypotaurine and betaine in D. globulus, and hypotaurine in L. fucensis. Both species had thiotaurine (as well as hypotaurine) at levels much greater than previously reported for vent and seep animals without endosymbionts. The ratio of thio- to thio- plus hypotaurine, a possible indicator of sulfide exposure, decreased in both species when kept in laboratory chambers with low or no sulfide, but stayed at high levels in snails kept with 3-5 mM sulfide. Thus, in some vent animals without endosymbionts, sulfide may be detoxified via conversion of hypotaurine to thiotaurine. The latter may be a marker of high sulfide exposure but not of thiotrophic endosymbionts. PMID:16788898

Rosenberg, Noah K; Lee, Raymond W; Yancey, Paul H

2006-08-01

322

Impact of the Colonization by Paralvinella sulfincola on the Microbial Diversity Associated with a Deep-Sea Hydrothermal Vent Sulfide Chimney (Axial Seamount, Juan de Fuca Ridge)  

NASA Astrophysics Data System (ADS)

In the early stages of high temperature deep-sea hydrothermal vent chimneys growth, the walls remain porous and allow the escape of hydrothermal 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 hydrothermal 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 hydrothermal vent sites, the Epsilon-Proteobacteria and the Deep-sea Hydrothermal Vent 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.

Page, A.; Juniper, K.; Olagnon, M.; Alain, K.; Desrosiers, G.; Querellou, J.; Cambon-Bonavita, M.

2002-12-01

323

Rare-earth elements and uranium in high-temperature solutions from East Pacific Rise hydrothermal vent field (13 N)  

Microsoft Academic Search

The mobility of rare-earth elements (REE) and U during hydrothermal alteration of the basalts at spreading centres has long been a matter of concern because of its bearing on the evolution and recycling of the oceanic crust1-6. Previous approaches to this problem have been indirect, through studies on altered dredged basalts or ophiolites. We report here sampling of hydrothermal vent

A. Michard; F. Albarde; G. Michard; J. F. Minster; J. L. Charlou

1983-01-01

324

Deposition of talc - kerolite-smectite - smectite at seafloor hydrothermal vent fields: Evidence from mineralogical, geochemical and oxygen isotope studies  

USGS Publications Warehouse

Talc, kerolite-smectite, smectite, chlorite-smectite and chlorite samples from sediments, chimneys and massive sulfides from six seafloor hydrothermal areas have been analyzed for mineralogy, chemistry and oxygen isotopes. Samples are from both peridotite- and basalt-hosted hydrothermal systems, and basaltic systems include sediment-free and sediment-covered sites. Mg-phyllosilicates at seafloor hydrothermal sites 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 hydrothermal 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 hydrothermal mounds, are lower-temperature (150-200????C) phases produced by diffuse fluid discharge through the sediment around the hydrothermal 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 hydrothermal fluid). Higher silica activity favors the formation of talc relative to tri-octahedral smectite. Vent structures and sedimentary cover preclude complete mixing of hydrothermal 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 hydrothermal 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 hydrothermal alteration products of the background turbiditic sediment. ?? 2007 Elsevier B.V. All rights reserved.

Dekov, V.M.; Cuadros, J.; Shanks, W.C.; Koski, R.A.

2008-01-01

325

Genetic diversity and demographic instability in Riftia pachyptila tubeworms from eastern Pacific hydrothermal vents  

PubMed Central

Background Deep-sea hydrothermal vent 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 vents 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 vent 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. PMID:21489281

2011-01-01

326

Genetic diversity and demographic instability in Riftia pachyptila tubeworms from eastern Pacific hydrothermal vents  

USGS Publications Warehouse

Background: Deep-sea hydrothermal vent 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 vents 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 vent 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.

Coykendall, D.K.; Johnson, S.B.; Karl, S.A.; Lutz, R.A.; Vrijenhoek, R.C.

2011-01-01

327

Comparative metagenomics of microbial communities inhabiting deep-sea hydrothermal vent chimneys with contrasting chemistries  

PubMed Central

Deep-sea hydrothermal vent 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 hydrothermal vent 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 vent 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 CalvinBensonBassham 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

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

2011-01-01

328

Comparative metagenomics of microbial communities inhabiting deep-sea hydrothermal vent chimneys with contrasting chemistries.  

PubMed

Deep-sea hydrothermal vent 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 hydrothermal vent 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 vent 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

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

2011-03-01

329

Characterizing Microbial Community and Geochemical Dynamics at Hydrothermal Vents Using Osmotically Driven Continuous Fluid Samplers  

SciTech Connect

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 hydrothermal vents, where the ephemeral nature of venting 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 hydrothermal vents 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.

Robidart, Julie C.; Callister, Stephen J.; Song, Peng F.; Nicora, Carrie D.; Wheat, Charles G.; Girguis, Peter R.

2013-05-07

330

Short-term temperature variability in the Rose Garden hydrothermal vent field: an unstable deep-sea environment  

NASA Astrophysics Data System (ADS)

Temperature was measured within the animal communities of the Rose Garden hydrothermal vent field with three thermistors that were left in place for a period of 72 h. The highest mean temperature (5.54C) was measured at a thermistor placed in the central clump of vestimentiferan worms, while the lowest mean value (2.26C) was recorded over the basaltic substrate. The temperature of the ambient water in the field was 2.07C. The site with the highest temperature was characterized by extreme variability in the temperature, with minimum values of 2.16C and maximum values of 14.81C. The temperature fluctuated over all of the time scales studied from 1 s to 72 h. There was no clear periodicity to the temperature fluctuations, however. These temperature fluctuations must have significant impacts on adaptations, by the animals of the vent community. In fact, the variability in temperature may be more important to the community than the mean temperature value to which they are exposed.

Johnson, Kenneth S.; Childress, James J.; Beehler, Carl L.

1988-10-01

331

Assessing the influence of physical, geochemical and biological factors on anaerobic microbial primary productivity within hydrothermal vent chimneys.  

PubMed

Chemosynthetic primary production supports hydrothermal vent ecosystems, but the extent of that productivity and its governing factors have not been well constrained. To better understand anaerobic primary production within massive vent deposits, we conducted a series of incubations at 4, 25, 50 and 90C using aggregates recovered from hydrothermal vent structures. We documented in situ geochemistry, measured autochthonous organic carbon stable isotope ratios and assessed microbial community composition and functional gene abundances in three hydrothermal vent chimney structures from Middle Valley on the Juan de Fuca Ridge. Carbon fixation rates were greatest at lower temperatures and were comparable among chimneys. Stable isotope ratios of autochthonous organic carbon were consistent with the Calvin-Benson-Bassham cycle being the predominant mode of carbon fixation for all three chimneys. Chimneys exhibited marked differences in vent fluid geochemistry and microbial community composition, with structures being differentially dominated by gamma (?) or epsilon (?) proteobacteria. Similarly, qPCR analyses of functional genes representing different carbon fixation pathways showed striking differences in gene abundance among chimney structures. Carbon fixation rates showed no obvious correlation with observed in situ vent fluid geochemistry, community composition or functional gene abundance. Together, these data reveal that (i) net anaerobic carbon fixation rates among these chimneys are elevated at lower temperatures, (ii) clear differences in community composition and gene abundance exist among chimney structures, and (iii) tremendous spatial heterogeneity within these environments likely confounds efforts to relate the observed rates to in situ microbial and geochemical factors. We also posit that microbes typically thought to be mesophiles are likely active and growing at cooler temperatures, and that their activity at these temperatures comprises the majority of endolithic anaerobic primary production in hydrothermal vent chimneys. PMID:23551687

Olins, H C; Rogers, D R; Frank, K L; Vidoudez, C; Girguis, P R

2013-05-01

332

Permeability changes due to mineral diagenesis in fractured crust: implications for hydrothermal circulation at  

E-print Network

is consistent with recent seismic data showing hydrothermal vents located at seismologically active ridge segments. ? 2001 Elsevier Science B.V. All rights reserved. Keywords: hydrothermal vents; convection. The discovery of vent sites discharging hot £uids is the best evidence of hot hydrothermal activity at ridge cr

Manga, Michael

333

Barite in hydrothermal environments as a recorder of subseafloor processes: a multiple-isotope study from the Loki's Castle vent field.  

PubMed

Barite chimneys are known to form in hydrothermal systems where barium-enriched fluids generated by leaching of the oceanic basement are discharged and react with seawater sulfate. They also form at cold seeps along continental margins, where marine (or pelagic) barite in the sediments is remobilized because of subseafloor microbial sulfate reduction. We test the possibility of using multiple sulfur isotopes (?34S, ?33S, ?36S) of barite to identify microbial sulfate reduction in a hydrothermal system. In addition to multiple sulfur isotopes, we present oxygen (?18O) and strontium (87Sr/86Sr) isotopes for one of numerous barite chimneys in a low-temperature (~20 C) venting area of the Loki's Castle black smoker field at the ultraslow-spreading Arctic Mid-Ocean Ridge (AMOR). The chemistry of the venting 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 site is further supported by the multiple sulfur isotopic composition of framboidal pyrite in the flow channel of the barite chimney and in the hydrothermal sediments in the barite field, as well as by low SO4 and elevated H2S concentrations in the venting 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 hydrothermal systems are promising sites to explore the interactions between the geosphere and biosphere in order to evaluate the microbial impact on these systems. PMID:24725254

Eickmann, B; Thorseth, I H; Peters, M; Strauss, H; Brcker, M; Pedersen, R B

2014-07-01

334

Draft Genome of Pseudomonas stutzeri Strain NF13, a Nitrogen Fixer Isolated from the Galapagos Rift Hydrothermal Vent.  

PubMed

Pseudomonas stutzeri strain NF13 was isolated from a water sample taken at a hydrothermal vent in the Galapagos rift. It was selected for its ability to metabolize sulfur compounds and to grow diazotrophically. Here, we report the first draft genome of a member of genomovar 19 of the species. PMID:23516224

Pea, Arantxa; Busquets, Antonio; Gomila, Margarita; Mayol, Joan; Bosch, Rafael; Nogales, Balbina; Garca-Valds, Elena; Bennasar, Antonio; Lalucat, Jorge

2013-01-01

335

Culture-independent characterization of a novel microbial community at a hydrothermal vent at Brothers volcano, Kermadec arc, New Zealand  

Microsoft Academic Search

The bacterial and archaeal diversity of a hydrothermal vent microbial community at Brothers volcano situated in the Kermadec arc, ?400 km off the north coast of New Zealand, was examined using culture-independent molecular analysis. An unusual microbial community was detected with only 1% and 40% of the bacterial phylotypes exhibiting >92% small subunit (SSU) rRNA gene sequence similarity with cultivated

M. B. Stott; J. A. Saito; M. A. Crowe; P. F. Dunfield; S. Hou; E. Nakasone; C. J. Daughney; A. V. Smirnova; K. Takai; M. Alam

2008-01-01

336

*Maractis rimicarivora*, a new genus and species of sea anemone (Cnidaria: Anthozoa: Actiniaria: Actinostolidae) from an Atlantic hydrothermal vent  

E-print Network

*Maractis rimicarivora* is a new genus and new species of medium-sized sea anemone (Actiniaria) from the TAG (Trans-Atlantic Geotraverse) hydrothermal vent fields (2608.3'N, 4449.6'W; 3650 m). The genus, which belongs to family Actinostolidae...

Fautin, Daphne G.; Barber, Brian R.

1999-01-01

337

Discovery of Nascent Vents and Recent Colonization Associated with(Re)activated Hydrothermal Vent Fields by the GALREX 2011 Expedition on the Galpagos Rift  

NASA Astrophysics Data System (ADS)

GALREX 2011 was a NOAA OER telepresence cruise that explored the diverse habitats and geologic settings of the deep Galpagos 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) hydrothermal venting near 88 W, now known as Uka Pacha and Pegasus Vent 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 hydrothermal habitats through volcanic eruptions and/or diking events, which may have taken place over a 15 km span separating the two vent fields. The Rosebud vent field at 86W was not observed and may have been covered with lava since last visited in 2005. A hydrothermal vent field near 86W was discovered that is one of the largest vent fields known on the Rift (120m by 40m). Low-temperature vent 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 vent-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 Vent 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 vent-endemic fauna that can be considered to be recent arrivals and colonizers (less than a few months) at Galapagos vent 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 hydrothermal habitat turnover via eruption, dike injection, or venting cessation may be considerably higher than previously thought along the Galpagos Rift.

Shank, T. M.; Holden, J. F.; Herrera, S.; Munro, C.; Muric, T.; Lin, J.; Stuart, L.

2011-12-01

338

The Oxygen Isotope Composition of PO4 Extracted From Lost City Hydrothermal Vents -- a Potential Biosignature for Vent Hosted Microbial Ecosystems  

NASA Astrophysics Data System (ADS)

The oxygen isotope composition of phosphate is a useful indicator of biological P cycling in low to moderate temperature environments, such as those that characterize most of the habitable zone of Earth. In microbially active systems, phosphate oxygen isotope compositions are driven towards a temperature- dependent, thermodynamic equilibrium offset from water. Enzymatic reactions involving organophosphorus compounds, pyrophosphate, and polyphosphates promote the exchange of oxygen atoms between water and phosphate. These enzyme driven reactions are key to the attainment of isotopic equilibrium under conditions in which the rate of inorganic oxygen exchange is slow. We have examined the phosphate oxygen isotope systematics of the Lost City hydrothermal vent system, which is located on a gabbroic and peridotitic massif, 15km off-axis of the Mid Atlantic Ridge. The Lost City hydrothermal system's fluid chemistry and heat budget are controlled by serpentinization reactions. Fluids vent at temperatures up to around 80C and with a pH around 9-10. Vent mineralogy is dominated by calcite, aragonite, and brucite, with mineral layers intercalated by biofilms. Phosphorus content ranges from 400 - 1000 ppm (by mass as P2O5) in the vent samples we have analyzed. The oxygen isotope composition of phosphate extracted from the vent solids is a few per mil lighter than that of phosphate dissolved in ambient sea water. This oxygen isotope composition reflects exchange of phosphate oxygen with water oxygen at elevated temperature. We show that under a wide range of conditions, abiological reaction rates are too slow to produce these isotopic compositions. This suggests that cycling of the phosphate by the vent system's microbial community has imprinted the phosphate with a stable isotope signature of biological activity. The oxygen isotope composition of lattice-bound phosphate preserves well in the geologic record, commending phosphate oxygen isotope measurements as a tool for the detection of life in ancient terrestrial and in extraterrestrial rocks.

Robinson, K. L.; Kelley, D. S.; Fogel, M. L.; Colman, A. S.

2008-12-01

339

Quantitative Population Analysis of Some Groups of Epsilon-Proteobacteria, Using in situ Growth Chamber Samples From Hydrothermal Vents in the South Mariana  

NASA Astrophysics Data System (ADS)

To reveal deep-sea hydrothermal microbial ecosystems, we have developed and applied several new sampling systems, e.g., in situ filter samplers and in situ growth chambers. The later enables to incubate and accumulate microbes inside a hydrothermal vent with complex physico-chemical gradients naturally created in a vent flow. Using this system, we have found several novel phylotypes of microbes in the Suiyo Seamount. Among them, two novel groups of epsilon-Proteobacteria (SSSV-BE1 and SSSV-BE2; Higashi et al. FEMS-ME 2004) were assumed to originate from sub-vent fields, mainly at the borehole SH-APSK05. Some of the known epsilon groups, i.e., CorreOs Groups D (the hydrothermal vent type) and Group B (the microbial mat type), were also detected in the same samples. Afterwards, we have further improved in situ growth chambers larger to gain enough amounts of microbial RNA samples for quantitative population analyses. A new chamber system named column-II type was then applied to a natural vent at Fryer site in the Mariana Trough, with temperatures of venting fluids beyond 109 C. Through the 16S rRNA gene clone library analysis, members of the above epsilon-Proteobacteria groups were frequently found in this column-II chamber sample, as well as the Suiyo Seamout samples. So, we tried to estimate population sizes of these epsilons by a quantitative fluorescent dot-blot hybridization (FDBH) technique. First, we newly designed two novel oligonucleotide probes specific to members of the groups D (26 mer) and SSSV-BE1 (23 mer), in which the stringency was checked using soft wares from Ribosomal Database Project II and DDBJ. Total RNA samples, after extracted and purified from the chamber samples, were applied to a nylon membrane filter and hybridized with these two specific probes, as well as Eubacteria, Universal, and some sub-domain/group-specific probes. After the hybridization, resulting fluorescence intensities were quantified, averaged, and compared each other, and then the target microbial population was calculated. Finally, we estimated the relative abundance of these epsilon-Proteobacteria groups in the total Bacteria, and the results implied that more SSSV-BE and group D exist as it goes to the deeper sub-vent. Further examinations of the population, and of whether this phenomenon can be observed commonly such as from the Suiyo Seamount samples, are carried out at the moment.

Miyako, C.; Higashi, Y.; Maruyama, A.

2004-12-01

340

Microbial community structure and functioning in marine sediments associated with diffuse hydrothermal venting assessed by integrated meta-omics.  

PubMed

Deep-sea hydrothermal vents are unique environments on Earth, as they host chemosynthetic ecosystems fuelled by geochemical energy with chemolithoautotrophic microorganisms at the basis of the food webs. Whereas discrete high-temperature venting systems have been studied extensively, the microbiotas associated with low-temperature diffuse venting are not well understood. We analysed the structure and functioning of microbial communities in two diffuse venting sediments from the Jan Mayen vent fields in the Norwegian-Greenland Sea, applying an integrated 'omics' approach combining metatranscriptomics, metaproteomics and metagenomics. Polymerase chain reaction-independent three-domain community profiling showed that the two sediments hosted highly similar communities dominated by Epsilonproteobacteria, Deltaproteobacteria and Gammaproteobacteria, besides ciliates, nematodes and various archaeal taxa. Active metabolic pathways were identified through transcripts and peptides, with genes of sulphur and methane oxidation, and carbon fixation pathways highly expressed, in addition to genes of aerobic and anaerobic (nitrate and sulphate) respiratory chains. High expression of chemotaxis and flagella genes reflected a lifestyle in a dynamic habitat rich in physico-chemical gradients. The major metabolic pathways could be assigned to distinct taxonomic groups, thus enabling hypotheses about the function of the different prokaryotic and eukaryotic taxa. This study advances our understanding of the functioning of microbial communities in diffuse hydrothermal venting sediments. PMID:24112684

Urich, Tim; Lanzn, Anders; Stokke, Runar; Pedersen, Rolf B; Bayer, Christoph; Thorseth, Ingunn H; Schleper, Christa; Steen, Ida H; Ovreas, Lise

2014-09-01

341

First Discovery and Investigation of a High-Temperature Hydrothermal Vent Field on the Ultra- Slow Spreading Southwest Indian Ridge  

NASA Astrophysics Data System (ADS)

Two recent cruises on board the Chinese research vessel Dayang Yihao have successfully investigated the first active hydrothermal vent field to be located along the ultraslow spreading Southwest Indian Ridge (SWIR) and collected hydrothermal sulfide deposit samples. The newly discovered hydrothermal vent field is located on the western end of a magmatically robust spreading segment immediately west of the Gallieni transform fault. Preliminary evidence of strong turbidity anomalies was first measured during a Nov. 2005 cruise on board Dayang Yihao (InterRidge News, vol. 15, pp. 33-34, 2006). Color video footages of the seafloor in the vent-field area were first obtained by a deep-towed video camera in February 2007 during DY115-19 Leg 1, when significant water column turbidity anomalies, noticeable temperature anomalies and methane anomalies were also measured. The vent field was then precisely located, mapped, and photographed in great detail in February- March 2007 during the DY115-19 Leg 2, using the autonomous underwater vehicle ABE of the Woods Hole Oceanographic Institution. A high-resolution bathymetric map, more than 5,000 near-bottom color photos, and several types of water column data were all obtained during three phases of ABE dives. Within the approximately 120-m-long by 100-m-wide hydrothermal field, three groups of active high-temperature vents were identified and color images of black smokers and associated biological communities were obtained from ABE, flying 5 m above the seafloor. Hydrothermal sulfide deposits were then successfully obtained using a TV-guided grab.

Tao, C.; Lin, J.; Guo, S.; Chen, Y. J.; Wu, G.; Han, X.; German, C. R.; Yoerger, D. R.; Zhu, J.; Zhou, N.; Su, X.; Baker, E. T.; Party, S.

2007-12-01

342

Phylogenetic diversity of methanogenic, sulfate-reducing and methanotrophic prokaryotes from deep-sea hydrothermal vents and cold seeps  

NASA Astrophysics Data System (ADS)

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 vent chimneys (Rainbow and Logatchev hydrothermal vent fields, Mid-Atlantic Ridge, Atlantic Ocean; 9N 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 hydrothermal vent 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 sites were found to be related to Type I methanotrophic members of the ?-proteobacteria, and were primarily distributed among three major clusters of sequences. No Type II pmoA sequences related to methanotrophic members of the ?-proteobacteria were detected, suggesting that the methanotrophic communities in these cold-seep areas are dominated by Type I ?-proteobacteria.

Reed, Andrew J.; Dorn, Ruth; Van Dover, Cindy L.; Lutz, Richard A.; Vetriani, Costantino

2009-09-01

343

Nitrogen fixation at 92 degrees C by a hydrothermal vent archaeon.  

PubMed

A methanogenic archaeon isolated from deep-sea hydrothermal vent fluid was found to reduce N(2) to NH(3) at up to 92 degrees C, which is 28 degrees C higher than the current upper temperature limit of biological nitrogen fixation. The 16S ribosomal RNA gene of the hyperthermophilic nitrogen fixer, designated FS406-22, was 99% similar to that of non-nitrogen fixing Methanocaldococcus jannaschii DSM 2661. At its optimal growth temperature of 90 degrees C, FS406-22 incorporated (15)N(2) and expressed nifH messenger RNA. This increase in the temperature limit of nitrogen fixation could reveal a broader range of conditions for life in the subseafloor biosphere and other nitrogen-limited ecosystems than previously estimated. PMID:17170307

Mehta, Mausmi P; Baross, John A

2006-12-15

344

Major transitions in evolution linked to thermal gradients above hydrothermal vents  

E-print Network

The emergence of the main divisions of today's life: (1) unicellular prokaryotes, (2) unicellular eukaryotes, (3) multicellular eukaryotes, and (4) metazoans, are examples of the--still unexplained--major transitions in evolution. Regarding the origin of life, I have proposed that primordial life functioned as heat engine (thermosynthesis) while thermally cycled in convecting volcanic hot springs. Here I argue for a role of thermal gradients above submarine hydrothermal vents (SHV) in several major transitions. The last decade has witnessed the emergence of phononics, a novel discipline in physics based on controlled heat transport in thermal gradients. It builds thermal analogs to electronic devices: the thermal diode, the thermal transistor, the thermal switch, the thermal amplifier, the thermal memory--the thermal computer has been proposed. Encouraged by (1) the many similarities between microtubules (MT) and carbon nanotubes, which have a very high thermal conductivity, and (2) the recent discovery of a ...

Muller, Anthonie W J

2012-01-01

345

Protection mechanisms of the iron-plated armor of a deep-sea hydrothermal vent gastropod  

PubMed Central

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 hydrothermal vent 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

Yao, Haimin; Dao, Ming; Imholt, Timothy; Huang, Jamie; Wheeler, Kevin; Bonilla, Alejandro; Suresh, Subra; Ortiz, Christine

2010-01-01

346

Mineralized iron oxidizing bacteria from hydrothermal vents: targeting biosignatures on Mars  

NASA Astrophysics Data System (ADS)

Putative hydrothermal systems have been identified on Mars based on orbital imagery and rover-based analyses. Based on Earth analogs, hydrothermal 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 hydrothermal 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 hydrothermal vents along Explorer Ridge, NE Pacific Ocean. In addition, microaerophilic iron oxidizing bacteria, isolated from active Pacific hydrothermal vents, 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 hydrothermal 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 hydrothermal systems represent an attractive target for future surface and sample return missions.

Leveille, R. J.

2010-12-01

347

Metatranscriptomics reveal differences in in situ energy and nitrogen metabolism among hydrothermal vent snail symbionts  

PubMed Central

Despite the ubiquity of chemoautotrophic symbioses at hydrothermal vents, 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 vent snail, in which specific hostsymbiont 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

Sanders, J G; Beinart, R A; Stewart, F J; Delong, E F; Girguis, P R

2013-01-01

348

Distinct patterns of genetic differentiation among annelids of eastern Pacific hydrothermal vents.  

PubMed

Population genetic and phylogenetic analyses of mitochondrial COI from five deep-sea hydrothermal vent annelids provided insights into their dispersal modes and barriers to gene flow. These polychaetes inhabit vent fields located along the East Pacific Rise (EPR) and Galapagos Rift (GAR), where hundreds to thousands of kilometers can separate island-like populations. Long-distance dispersal occurs via larval stages, but larval life histories differ among these taxa. Mitochondrial gene flow between populations of Riftia pachyptila, a siboglinid worm with neutrally buoyant lecithothrophic larvae, is diminished across the Easter Microplate region, which lies at the boundary of Indo-Pacific and Antarctic deep-sea provinces. Populations of the siboglinid Tevnia jerichonana are similarly subdivided. Oasisia alvinae is not found on the southern EPR, but northern EPR populations of this siboglinid are subdivided across the Rivera Fracture Zone. Mitochondrial gene flow of Alvinella pompejana, an alvinellid with large negatively buoyant lecithotrophic eggs and arrested embryonic development, is unimpeded across the Easter Microplate region. Gene flow in the polynoid Branchipolynoe symmytilida also is unimpeded across the Easter Microplate region. However, A. pompejana populations are subdivided across the equator, whereas B. symmitilida populations are subdivided between the EPR and GAR axes. The present findings are compared with similar evidence from codistributed species of annelids, molluscs and crustaceans to identify potential dispersal filters in these eastern Pacific ridge systems. PMID:15315674

Hurtado, L A; Lutz, R A; Vrijenhoek, R C

2004-09-01

349

Exopolysaccharides Isolated from Hydrothermal Vent Bacteria Can Modulate the Complement System  

PubMed Central

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 hydrothermal vent 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 vent bacteria in order to find pro or anti-activators of complement. PMID:24736648

Courtois, Anthony; Berthou, Christian; Guzennec, Jean

2014-01-01

350

Characterization of Large, Autotrophic Beggiatoa spp. Abundant at Hydrothermal Vents of the Guaymas Basin  

PubMed Central

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 hydrothermal vents 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 ?m). The average widths of the Beggiatoa classes were 24 to 32, 40 to 42, and 116 to 122 ?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 CO2 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 CO2 fixation rates, sulfide stimulation of incorporation, and autoradiographic studies suggest that these Beggiatoa spp. contribute significantly as lithoautrophic primary producers to the Guaymas Basin vent ecosystems. Images PMID:16348053

Nelson, Douglas C.; Wirsen, Carl O.; Jannasch, Holger W.

1989-01-01

351

Exopolysaccharides isolated from hydrothermal vent bacteria can modulate the complement system.  

PubMed

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 hydrothermal vent 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 vent bacteria in order to find pro or anti-activators of complement. PMID:24736648

Courtois, Anthony; Berthou, Christian; Guzennec, Jean; Boisset, Claire; Bordron, Anne

2014-01-01

352

Characterization of large, autotrophic Beggiatoa spp. abundant at hydrothermal vents of the Guaymas Basin  

SciTech Connect

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 hydrothermal vents 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 vent ecosystems.

Nelson, D.C. (Univ. of California, Davis (USA)); Wirsen, C.O.; Jannasch, H.W. (Woods Hole Oceanographic Institution, MA (USA))

1989-11-01

353

Microearthquakes Beneath the Endeavour Hydrothermal Vent Fields: Insights Into Reaction Zone Processes  

NASA Astrophysics Data System (ADS)

From 2003-2006, a novel seismic network comprising seven short-period corehole seismometers and a broadband Guralp CMG-1T OBS was deployed using remotely operated vehicles in a subseafloor configuration on the Endeavour segment of the Juan de Fuca mid-ocean ridge. The seismic monitoring array was one part of a multi-disciplinary prototype NEPTUNE experiment designed to investigate the linkages between seismic deformation, hydrothermal fluxes, and microbial productivity along oceanic plate boundaries. The seismic network recorded high-quality data that illustrate the advantages of using an ROV to deploy seismometers in well- coupled configurations that are also away from the effects of ocean currents. A preliminary analysis of the first year of Keck seismic data was undertaken during a research apprenticeship class taught in the fall of 2004 at the University of Washington's Friday Harbor Laboratories. Eight post- baccalaureate students obtained a preliminary catalog of nearly 13,000 earthquakes on the Endeavour segment. Two of the apprentices conducted a second-pass analysis to refine the locations of ~3000 earthquakes that are within or near the network. Further analysis of these proximal earthquakes has focused on the application of cross-correlation and relative relocation techniques, the determination of focal mechanisms using P-wave first motions and P- to S-wave amplitudes ratios, and improved estimates of earthquake magnitudes. The results show that the entire Endeavour segment was seismically active during 2003-2004. Within the network, the earthquakes are located in tight clusters centered at ~2 km depth in the inferred location of the hydrothermal reaction zone immediately above a crustal magma chamber imaged by seismic reflection studies. The number of earthquakes below each hydrothermal vent field correlates with the heat flux measured by other researchers and the vertical thickness of this reaction zone, inferred from the distribution of seismicity, is ~0.5-1 km. Preliminary focal mechanisms show a transition from ridge-perpendicular extension beneath the rise axis to ridge-perpendicular compression on either side over horizontal distances of <1 km. This is most simply explained if the stress field above the magma chamber is locally influenced by either the injection of magma or over-pressured hydrothermal fluids. This observation, in combination with a reaction zone thickness that is at least an order of magnitude larger than that inferred from thermal boundary layer theory, suggests that the heat transfer between the magmatic and hydrothermal systems is not simply the result of cold water attacking hot magma. Instead, it appears as though the magmatic system also attacks the reaction zone from below.

Wilcock, W. S.; Hooft, E. E.; McGill, P. R.; Toomey, D. R.; Barclay, A. H.; Stakes, D. S.; Ramirez, T. M.

2007-12-01

354

Hydrothermal Activity on the Southern Mid-Atlantic Ridge: Tectonically- and Volcanically-Hosted High Temperature Venting at 2-7 Degrees S  

NASA Astrophysics Data System (ADS)

We have conducted a systematic investigation for hydrothermal 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 sites of hydrothermal 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 vent ecosystems. During the first leg of our research cruise (RRS Charles Darwin cruise CD169, Feb-Mar 2005) we used this approach to identify two hydrothermally 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 hydrothermal 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 hydrothermal plumes rising from the seafloor. Finally we redeployed ABE (Phase 3) to collect photo-mosaics of each of two new vent-areas whilst simultaneously sampling their buoyant plumes by CTD-rosette for TDMn, Fe and CH4 analyses.

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.

2005-12-01

355

Life and Death of Deep-Sea Vents: Bacterial Diversity and Ecosystem Succession on Inactive Hydrothermal Sulfides  

PubMed Central

ABSTRACT Hydrothermal chimneys are a globally dispersed habitat on the seafloor associated with mid-ocean ridge (MOR) spreading centers. Active, hot, venting 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 sulfidesstructures 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 hydrothermal sulfide chimney samples from 9N on the East Pacific Rise to learn their bacterial composition, metabolic potential, and succession from venting 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 vents, 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 hydrothermal sulfides. These shifts in bacterial population structure on inactive chimneys reveal ecological succession following cessation of venting and also imply a potential shift in microbial activity and metabolic guilds on hydrothermal sulfides, the dominant biome that results from seafloor venting. PMID:22275502

Sylvan, Jason B.; Toner, Brandy M.; Edwards, Katrina J.

2012-01-01

356

Multidisciplinary Investigations of the Galpagos Rift, 86W to 89.5W: 25th Anniversary of the Discovery of Hydrothermal Venting  

NASA Astrophysics Data System (ADS)

In May-June, 2002, a multidisciplinary expedition comprised of biologists, chemists, geologists and engineers conducted a field program on the Galpagos Rift between 86W and 89.5W. Objectives of the expedition included revisiting the site of one of the first-discovered low-temperature hydrothermal vents at Rose Garden (originally found in 1979), and searching for new low- and high-temperature vents along the largely unexplored western portion of the Galpagos Rift to 89.5W. The field work was funded primarily by NOAA's Ocean Exploration Program with additional support from the National Science Foundation and Woods Hole Oceanographic Institution. A synergistic array of deep-ocean vehicles was used for the exploration program. Alvin and a new digital towed camera were used for making seafloor observations, acquiring digital imagery and collecting samples. An autonomous vehicle ABE (Autonomous Benthic Explorer), which acquired meter-scale bathymetry, near-bottom magnetics and bottom water-properties data, was utilized to explore for active hydrothermal venting. Water-column vertical casts and tow-yos with a CTD/rosette were used to explore for plumes emanating from high-temperature vents. Alvin and ABE were used to explore for the Rose Garden vent field near 8613.5'W. Detailed bottom-water temperature maps and seafloor magnetics data, in conjunction with visual and photographic observations from Alvin and the towed camera, confirmed that the Rose Garden vent field and associated animal community no longer exists, and that prolonged high-temperature venting appears to never have occurred in this area. However, a new low-temperature vent field (which was named Rosebud) was discovered nearby at a depth of 2450 m, and was found to be developing on a fresh-looking sheet flow at a location approximately 200 m northwest of the former Rose Garden area. A second site of low-temperature hydrothermal activity, at 1670 m, was discovered on a portion of the unexplored rift near 89.5W. This venting is the first discovered along this portion of the Galpagos Rift and it hosts a large vesicomyid (C. magnifica) clam community that covers an approximately 60 m x 60 m area. Throughout the cruise, ABE was used during night operations to provide synoptic micro-bathymetry maps, magnetics data and bottom water properties. Early each morning, these data were processed and then provided to the Alvin observers prior to that same day's dive. ABE data were occasionally combined with, or supplanted by, data from the towed camera or the CTD. A total of 9 Alvin dives, 7 ABE dives, 5 camera tows and 6 CTD tows/casts were conducted. Detailed micro-bathymetric maps and mosaics of the vent communities will be presented.

Hammond, S. R.; Shank, T. M.; Fornari, D. J.; Yoerger, D. R.; Bradley, A. M.; Scheirer, D. S.; Tivey, M. A.

2002-12-01

357

First insights into macro- and meiofaunal colonisation patterns on paired wood/slate substrata at Atlantic deep-sea hydrothermal vents  

NASA Astrophysics Data System (ADS)

In 2006, paired wood and slate panels, each equipped with a temperature probe, were deployed on three different localities on and around the Eiffel Tower edifice (Lucky Strike vent field, Mid-Atlantic Ridge) within close proximity of visible hydrothermal activity. Recovery of these panels took place in 2008. For this two-year deployment period, the composition of colonising organisms (both macro-and meiofauna) was assessed, along with image analyses of the deployment sites in 2006 and 2008. Very few significant differences in colonisation between organic (wood) and inorganic (slate) panels were revealed. Rather, the locality of deployment and the local environmental conditions and hydrothermal activity were found to influence taxonomic composition. Variability in microhabitat conditions and biological interactions were hypothesised to interact jointly in shaping new faunal communities on the colonisation substrata.

Cuvelier, Daphne; Beesau, Julie; Ivanenko, Viatcheslav N.; Zeppilli, Daniela; Sarradin, Pierre-Marie; Sarrazin, Joze

2014-05-01

358

Geochemistry of hydrothermal fluids from Axial Seamount Hydrothermal Emissions Study vent field, Juan de Fuca Ridge: Subseafloor boiling and subsequent fluid-rock interaction  

Microsoft Academic Search

Hydrothermal fluids collected from the ASHES vent field in 1986, 1987, and 1988 exhibit a very wide range of chemical composition over a small area ( 60 m in diameter). Compositions range from a 300C, gas-enriched (285 mmol\\/kg CO), low-chlorinity ( 33% of seawater) fluid to a 328C, relatively gas-depleted (50 mmol\\/kg CO), high-chlorinity ( 116% of seawater) fluid. The

David A. Butterfield; R. E. McDuff; M. D. Lilley; G. J. Massoth; J. E. Lupton

1990-01-01

359

Uniformity and diversity in the composition of mineralizing fluids from hydrothermal vents on the southern Juan de Fuca Ridge  

SciTech Connect

Abundances of Li, Ni, K, Rb, Ca, Sr, Ba, Mn, Fe, Zn, and Si have been determined in fluid samples from seven vents located in three areas on the southern Juan de Fuca Ridge. The hydrothermal 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 hydrothermal 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 vent areas. Some uniform differences in the elemental abundances predicted for hydrothermal end-member fluids might be due to inmixing of fresh seawater at depth in the hydrothermal system. The Juan de Fuca hydrothermal 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

Philpotts, J.A.; Aruscavage, P.J.; Von Damm, K.L.

1987-10-10

360

Hydrothermal venting and basin evolution (Devonian, South China): Constraints from rare earth element geochemistry of chert  

NASA Astrophysics Data System (ADS)

This paper presents rare earth element (REE) geochemistry of siliceous deposits from which hydrothermal activity and basin evolution are elucidated, in the Late Devonian, in the Yangshuo basin, South China, where siliceous deposits widely occurred as nodular chert in the deep-water limestones and bedded chert interbeded with tuffaceous chert in the early Late Devonian. Both nodular and bedded cherts are characterized by very low La abundances (avg. 2.07 and 2.49 ppm, respectively), intermediate negative Ce anomalies (Ce/Ce*: avg. 0. 69 and 0.61), slight to intermediate positive Eu anomalies (Eu/Eu*: avg. 1.33 and 1.57), and low to intermediate shale-normalized La n/Yb n values (avg. 0.86 and 0.52) and intermediate La n/Ce n values (avg. 1.61 and 1.72). These suggest both nodular and bedded cherts formed in the open marine basin of South China, rather than in the intracontinental rift basin as previously assumed, with involvement both with seawaters as indicated by intermediate negative Ce anomalies and generally LREE-depleted patterns, and hydrothermal vent fluids as indicated by convex, less LREE-depleted patterns with apparent positive Eu anomalies. In comparison with nodular and bedded chert, the tuffaceous chert has the highest La abundances (avg. 17.11 ppm), similar ranges of Ce anomalies (avg. 0.63) and La n/Ce n values (avg. 1.77), but lower La n/Yb n values (avg. 0.48) and no apparent positive Eu anomalies (avg. 0.97). This suggests that the tuffaceous fallouts were also significantly modified by the hydrothermal fluid and seawater. Rapid spatial variations of Eu/Eu* values and degree of LREE-depletions in the studied basin are recognized, characterizing a spatially differential hydothermal activity that is not well discriminated by major element features. Such a difference in hydrothermal activity is interpreted as having been related to the intensity and depth of syndepositional tectonic activity, reconciling the structural pattern unraveled by stratigraphic packages.

Chen, Daizhao; Qing, Hairuo; Yan, Xin; Li, He

2006-01-01

361

Uniformity and diversity in the composition of mineralizing fluids from hydrothermal vents on the southern Juan de Fuca Ridge.  

USGS Publications Warehouse

Abundances of Li, Na, K, Rb, Ca, Sr, Ba, Mn, Fe, Zn, and Si have been determined in fluid samples from 7 vents located in three areas on the southern Juan de Fuca Ridge. The hydrothermal 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 hydrothermal fluids, but some Zn determinations and most Ba values appear to be too low.-from Authors

Philpotts, J.A.; Aruscavage, P. J.; Von Damm, K. L.

1987-01-01

362

Dominance of Epiphytic Filamentous Thiothrix spp. on an Aquatic Macrophyte in a Hydrothermal Vent Flume in Sedge Bay, Yellowstone Lake, Wyoming  

Microsoft Academic Search

Sublacustrine hydrothermal vents, geysers, and fumaroles impart regions of Yellowstone Lake with distinctive chemical compositions\\u000a that generate unique freshwater habitats and support diverse microbial life. Some microbial communities within Sedge Bay manifest\\u000a themselves as accumulations of white-colored films on the surfaces of aquatic macrophytes located within the hydrothermal\\u000a flow of vents. It was hypothesized that the white films were the

Nick R. Konkol; James C. Bruckner; Carmen Aguilar; David Lovalvo; James S. Maki

2010-01-01

363

Effects of sulfide exposure history and hemolymph thiosulfate on oxygen-consumption rates and regulation in the hydrothermal vent crab Bythograea thermydron  

Microsoft Academic Search

The hydrothermal vent crab Bythograea thermydron is exposed to high environmental concentrations of sulfide and low levels of oxygen for extended periods of time. It has previously been shown that hydrogen sulfide is oxidized to the relatively non-toxic thiosulfate (S2O32-), which accumulates in the hemolymph. Hemolymph thiosulfate levels in freshly captured crabs vary significantly among crabs from different hydrothermal vent

L. A. Gorodezky; J. J. Childress

1994-01-01

364

Temporal and spatial patterns of biological community development at nascent deep-sea hydrothermal vents (950?N, East Pacific Rise)  

Microsoft Academic Search

The April 1991 discovery of newly formed hydrothermal vents in areas of recent volcanic eruption between 945?N and 952?N on the East Pacific Rise provided a unique opportunity to follow temporal changes in biological community structure from the birth of numerous deep-sea hydrothermal vents. In March l992, DSV Alvin was used to deploy an on-bottom observatory, the BiologicGeologic Transect, to

Timothy M. Shank; Daniel J. Fornari; Karen L. Von Damm; Marvin D. Lilley; Rachel M. Haymon; Richard A. Lutz

1998-01-01

365

Phylogenetic relationships of Thiomicrospira species and their identification in deep-sea hydrothermal vent samples by denaturing gradient gel electrophoresis of 16S rDNA fragments  

Microsoft Academic Search

Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rDNA fragments was used to explore the genetic diversity\\u000a of hydrothermal vent microbial communities, specifically to determine the importance of sulfur-oxidizing bacteria therein.\\u000a DGGE analysis of two different hydrothermal vent samples revealed one PCR band for one sample and three PCR bands for the\\u000a other sample, which probably correspond to the dominant

Gerard Muyzer; Andreas Teske; Carl O. Wirsen; Holger W. Jannasch

1995-01-01

366

Near-bottom magnetic surveys around hydrothermal sites in the southern Mariana Trough  

NASA Astrophysics Data System (ADS)

Near-bottom magnetic survey is an effective method to reveal detailed magnetic anomaly features of seafloor. The measurements of three-components of the geomagnetic field by using AUV "URASHIMA" were conducted during the YK-09-08 cruise in the southern Mariana Trough in order to detect signals of hydrothermally altered rocks. During the cruise, vector geomagnetic field are successfully obtained along the all dive tracks with the information of the vehicle's attitude. Total intensities of geomagnetic field by the overhauser magnetometer were also conducted, but the data are only collected along almost E-W oriented observation lines due to the sensitivity of the sensor. The distribution of crustal magnetization are estimated using downward component of magnetic anomalies by the inversion method. The distribution of low crustal magnetization are almost coincide with the area around hydrothermal vent sites from on ridge to off ridge area, and most likely indicate signs of hydrothermally altered rocks. The distribution of low crustal magnetization on ridge are almost parallel to the the strike of ridge axis implying tectonic control of hydrothermal vent sites.

Nogi, Y.; Mochizuki, N.; Okino, K.; Asada, M.

2011-12-01

367

Two Novel Hepatocellular Carcinoma Cycle Inhibitory Cyclodepsipeptides from a Hydrothermal Vent Crab-Associated Fungus Aspergillus clavatus C2WU  

PubMed Central

Two novel cyclodepsipeptides containing an unusual anthranilic acid dimer and a d-phenyllactic acid residues, clavatustides A (1) and B (2), 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 hydrothermal vents 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 hydrothermal vent crab. Clavatustides A (1) and B (2) 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

Jiang, Wei; Ye, Panpan; Chen, Chen-Tung Arthur; Wang, Kuiwu; Liu, Pengyuan; He, Shan; Wu, Xiaodan; Gan, Lishe; Ye, Ying; Wu, Bin

2013-01-01

368

Hot vents in an ice-cold ocean: Indications for phase separation at the southernmost area of hydrothermal activity, Bransfield Strait, Antarctica  

NASA Astrophysics Data System (ADS)

During the expeditions ANT-XV/2 with R/V Polarstern in 1997/98 and NBP 99-04 with R/V IB N.B. Palmer in 1999, the first samples of hydrothermally influenced sediments of Bransfield Strait were obtained at Hook Ridge, a volcanic edifice in the Central Basin of the Strait. The vent sites are characterized by white siliceous crusts on top of the sediment layer and temperatures measured immediately on deck are up to 48.5C. The shallow depth of these vent sites (1050 m) particularly controls the chemistry of the pore fluids that are enriched in silica and sulfide and show low pH values. Chloride is depleted up to 20% and the calculated hydrothermal endmember concentration is in the range of 1-84 mM. Since other mechanisms for Cl depletion can be ruled out clearly, the composition of this fluid is attributed to phase separation. While the Cl-depleted fluid is emanating at Hook Ridge, a Cl-enriched fluid can be identified in the adjacent King George Basin. Using a p,x diagram the two corresponding endmember concentrations reveal that the phase separation takes place at subcritical conditions (total depth: 2500 m), probably along the whole volcanic edifice.

Dhlmann, A.; Wallmann, K.; Sahling, H.; Sarthou, G.; Bohrmann, G.; Petersen, S.; Chin, C. S.; Klinkhammer, G. P.

2001-12-01

369

Palaeococcus ferrophilus gen. nov., sp. nov., a barophilic, hyperthermophilic archaeon from a deep-sea hydrothermal vent chimney  

Microsoft Academic Search

A novel barophilic, hyperthermophilic archaeon was isolated from a deep-sea hydrothermal vent chimney at the Myojin Knoll in the Ogasawara-Bonin Arc, Japan. The cells were found to be irregular cocci and motile with multiple polar flagella. Growth was observed between 60 and 88SC (opt. 83SC; 30 min doubling time), pH 4<0 and 8<0 (opt. pH 6<0), 20 and 73 g

Ken Takai; Akihiko Sugai; Toshihiro Itoh; Koki Horikoshi

370

Hypotaurine and thiotaurine as indicators of sulfide exposure in bivalves and vestimentiferans from hydrothermal vents and cold seeps  

Microsoft Academic Search

Vesicomyid clams, vestimentiferans, and some bathymodiolin mussels from hydrothermal vents and cold seeps possess thiotrophic endosymbionts, high levels of hypotaurine and, in tissues with symbionts, thiotaurine. The latter, a product of hypotaurine and sulfide, may store and\\/or transport sulfide non-toxically, and the ratio to hypotaurine plus thiotaurine (Th\\/(H+Th)) may reflect an animal's sulfide exposure. To test this, we analyzed seep

Garth L. Brand; Robin V. Horak; Nadine Le Bris; Shana K. Goffredi; Susan L. Carney; Breea Govenar; Paul H. Yancey

2007-01-01

371

A Novel, Highly Viscous Polysaccharide Excreted by an Alteromonas Isolated from a Deep-Sea Hydrothermal Vent Shrimp  

Microsoft Academic Search

A deep-sea, mesophilic, aerobic, and heterotrophic microorganism, able to produce an extracellular polysaccharide, was isolated\\u000a from a shrimp collected near an active hydrothermal vent of the Mid-Atlantic Ridge. On the basis of phenotypic and phylogenetic\\u000a analyses and DNA\\/DNA relatedness, this strain could be assigned to the species Alteromonas macleodii as a variant of the fijiensis subspecies. It was selected for

Grard Raguns; Marie Anne Cambon-Bonavita; Jean Franois Lohier; Claire Boisset; Jean Guezennec

2003-01-01

372

Phylogenetic Characterization of the Bacterial Assemblage Associated with Mucous Secretions of the Hydrothermal Vent Polychaete Paralvinella Palmiformis  

NSDL National Science Digital Library

This FEMS Microbiology Ecology journal article features a culture-independent molecular analysis of the bacterial assemblage associated with mucous secretions of the Northeastern Pacific vent polychaete Paralvinella palmiformis. It reports the presence of Verrucomicrobia, Fusobacteria and green non-sulfur bacteria on hydrothermal edifices. The potential functions of the detected bacteria are discussed in terms of productivity, recycling of organic matter and detoxification within the P. palmiformis microhabitat.

373

Temporal Variations in Heterotrophic Mesophilic Bacteria from a Marine Shallow Hydrothermal Vent off the Island of Vulcano (Eolian Islands, Italy)  

Microsoft Academic Search

The fluctuations of the total microbial abundance, the culturable heterotrophic bacterial population, and the composition\\u000a of heterotrophic bacteria were investigated in relation to environmental parameters in a shallow, marine hydrothermal vent\\u000a off the Island of Vulcano (Eolian Islands, Italy). Standing stock dynamics were studied by measuring the total population\\u000a of picoplankton by direct count and the population of viable heterotrophic

C. Gugliandolo; T. L. Maugeri

1998-01-01

374

Molecular Identification and Localization of Filamentous Symbiotic Bacteria Associated with the Hydrothermal Vent AnnelidAlvinella pompejana  

Microsoft Academic Search

Alvinella pompejanais a polychaetous annelid that inhabits high-temperature environments associated with active deep-sea hydrothermal vents along the East Pacific Rise. A unique and diverse epibiotic microflora with a prominentfilamentous morphotype is found associated with the worm's dorsal integument. A previous study established the taxonomic positions of two epsilon proteobacterial phylotypes, 13B and 5A, which dominated aclonelibraryof16SrRNAgenesamplifiedbyPCRfromtheepibioticmicrobialcommunityofanA.pompejana specimen.InthepresentstudydeoxyoligonucleotidePCRprimersspecificforphylotypes13Band5Awereused to demonstrate that

S. CRAIG CARY; MATTHEW T. COTTRELL; JEFFREY L. STEIN; FRANCISCO CAMACHO; ANDDANIEL DESBRUYERES

1997-01-01

375

Spatial Heterogeneity of Bacterial Populations along an Environmental Gradient at a Shallow Submarine Hydrothermal Vent near Milos Island (Greece)  

Microsoft Academic Search

The spatial heterogeneity of bacterial populations at a shallow-water hydrothermal vent in the Aegean Sea close to the island of Milos (Greece) was examined at two different times by using acridine orange staining for total cell counts, cultivation-based techniques, and denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified 16S rRNA gene fragments. Concurrent with measurements of geochemical parameters, samples were

STEFAN M. SIEVERT; THORSTEN BRINKHOFF; GERARD MUYZER; WIEBKE ZIEBIS; JAN KUEVER

1999-01-01

376

Diversity of Dissimilatory Bisulfite Reductase Genes of Bacteria Associated with the Deep-Sea Hydrothermal Vent Polychaete Annelid Alvinella pompejana  

Microsoft Academic Search

A unique community of bacteria colonizes the dorsal integument of the polychaete annelid Alvinella pompe- jana, which inhabits the high-temperature environments of active deep-sea hydrothermal vents along the East Pacific Rise. The composition of this bacterial community was characterized in previous studies by using a 16S rRNA gene clone library and in situ hybridization with oligonucleotide probes. In the present

MATTHEW T. COTTRELL; S. CRAIG CARY

1999-01-01

377

Novel Bacterial and Archaeal Lineages from an In Situ Growth Chamber Deployed at a Mid-Atlantic Ridge Hydrothermal Vent  

Microsoft Academic Search

The phylogenetic diversity was determined for a microbial community obtained from an in situ growth chamber placed on a deep-sea hydrothermal vent on the Mid-Atlantic Ridge (2322* N, 4457* W). The chamber was deployed for 5 days, and the temperature within the chamber gradually decreased from 70 to 20C. Upon retrieval of the chamber, the DNA was extracted and the

ANNA-LOUISE REYSENBACH; KRISTA LONGNECKER; JULIE KIRSHTEIN

2000-01-01

378

ϵ-Proteobacterial diversity from a deep-sea hydrothermal vent on the Mid-Atlantic Ridge  

Microsoft Academic Search

The prokaryotic phylogenetic diversity was determined for a sample associated with an in situ growth chamber deployed for 5 days on a Mid-Atlantic Ridge hydrothermal vent (2322PN, 4457PW). The DNA was extracted from the sample and the 16S rDNA amplified by PCR. No Archaea were detected in the sample. Eighty-seven clones containing bacterial 16S rDNA inserts were selected. Based on

Erwan Corre; Anna-Louise Reysenbach; Daniel Prieur

2001-01-01

379

Molecular identification of differentially regulated genes in the hydrothermal-vent species Bathymodiolus thermophilus and Paralvinella pandorae in response to temperature  

Microsoft Academic Search

BACKGROUND: Hydrothermal vents and cold seeps represent oases of life in the deep-sea environment, but are also characterized by challenging physical and chemical conditions. The effect of temperature fluctuations on vent organisms in their habitat has not been well explored, in particular at a molecular level, most gene expression studies being conducted on coastal marine species. In order to better

Isabelle Boutet; Didier Jollivet; Bruce Shillito; Dario Moraga; Arnaud Tanguy

2009-01-01