These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
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

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

3

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.

2010-04-12

4

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

5

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

6

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

7

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.

8

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.

9

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

10

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

11

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

12

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

13

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.

14

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

15

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

16

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

17

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.

18

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

19

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

20

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

21

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

22

Site-related differences in gene expression and bacterial densities in the mussel Bathymodiolus azoricus from the Menez Gwen and Lucky Strike deep-sea hydrothermal vent sites.  

PubMed

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 hydrothermal vent sites and in close vicinity of the Azores region near the Mid-Atlantic Ridge (MAR). The physiological relationships that vent mussels have developed with their physical and chemical environments are likely to influence global gene expression profiles providing thus the means to investigate distinct biological markers predicting the origin of Bathymodiolus sp. irrespectively of their geographical localization. Differences found at gene expression levels, and between fluorescence in situ hybridization (FISH) and 16S rRNA amplicon sequencing results provided experimental evidence for the distinction of both Menez Gwen and Lucky Strike vent mussel individuals based on bacterial and vent mussel gene expression signatures and on the constitutive distribution and relative abundance of endosymbiotic bacteria within gill tissues. Our results confirmed the presence of methanotroph endosymbionts in Menez Gwen 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 a sulfur-oxidizing-related probe. Quantitative PCR (qPCR) studies revealed different gene expression profiles in both Menez Gwen and Lucky Strike mussel gill tissues for the immune genes selected. Genes encoding transcription factors presented noticeably low levels of fold expression whether in Menez Gwen or Lucky Strike animals whereas the genes encoding effector molecules appeared to have higher levels expression in gill tissues from Menez Gwen animals. The peptidoglycan recognition molecule encoding gene, PGRP, presented the highest level of transcriptional activity among the genes analyzed in Menez Gwen mussel gill tissues, seconded by carcinolectin and thus denoting the relevance of immune recognition molecules in early stage of the immune responses onset. Genes regarded as encoding molecules involved in signaling pathways were consistently expressed in both Menez Gwen and Lucky Strike mussel gill tissues. Remarkably, the immunity-related GTPase encoding gene demonstrated, in Lucky Strike samples, the highest level of expression among the signaling molecule encoding genes tested when expressions levels were compared between Menez Gwen and Lucky Strike animals. A differential expression analysis of bacterial genes between Menez Gwen and Lucky Strike mussels indicated a clear expression signature in the latter animal gill tissues. The bacterial community structure ensued from the 16S rRNA sequencing analyses pointed at an unpredicted conservation of endosymbiont bacterial loads between Menez Gwen and Lucky Strike samples. Taken together, our results support the hypothesis that B. azoricus exhibits different transcriptional statuses while living in distinct hydrothermal vent sites may result in distinct gene expressions because of physico-chemical and/or symbiont densities differences. PMID:24882018

Bettencourt, Raul; Rodrigues, Mnica; Barros, Ins; Cerqueira, Teresa; Freitas, Ctia; Costa, Valentina; Pinheiro, Miguel; Egas, Conceio; Santos, Ricardo Serro

2014-08-01

23

NOAA's VENTS program targets oceanic hydrothermal effects  

NASA Astrophysics Data System (ADS)

The VENTS Program was established in 1984 to focus interdisciplinary research of the National Oceanographic and Atmospheric Administration on the oceanic effects of hydrothermal activity along seafloor spreading centers. Since then, the accelerating rate of discoveries in this area of research has resulted in increased recognition of the importance of seafloor hydrothermal venting as a fundamental process for transfer of mass and heat from the Earth's interior to its surfacea process that is active intermittently, but not uncommonly, along the entire 60,000 km-long global spreading-center system. As the nation's civilian ocean agency, NOAA undertakes research to understand processes that affect the ocean environment. The VENTS program's highest priority is studies that address large-scale hydrothermal chemical and thermal effects on the ocean, or the potential for such effects, that manifest themselves over relatively short time periodsfrom years to centuries.

Hammond, S.; Fox, C.; Embley, R.; Baker, E.; Bernard, E.; Massoth, G.; Feely, R.; Cannon, G.; Rona, P.

24

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

25

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

26

Metals in the shell of Bathymodiolus azoricus from a hydrothermal vent site on the Mid-Atlantic Ridge.  

PubMed

Specimens of the mussel Bathymodiolus azoricus were collected from Menez Gwen, a relatively shallow (850 m) hydrothermal vent field on the Mid-Atlantic Ridge. Each bivalve shell (n = 21) was individually cleaned by selective chemical. The residual crystal matrix of each shell was individually analysed for the concentrations of the minor elements magnesium and strontium and the trace elements iron, manganese, copper and zinc. The chemical composition of the crystal matrix is unusual. B. azoricus is identified as a species having one of the most strontium impoverished shells amongst the marine molluscs. For a bimineral species the magnesium concentration is also extraordinary low. Despite originating from a trace metal rich environment; the metal concentrations in the shells were exceptionally low. Mean concentrations of iron, manganese, copper and zinc were 20.6, 3.7, 0.6 and 9.4 microg g(-1) respectively. Minor and trace element concentrations exhibited a marked intra-population variability. Copper concentrations increased and iron and zinc concentrations decreased with increasing shell weight. Due to its insensitivity to the high environmental levels of trace elements and the variability in intra-population concentrations induced by shell weight the crystal matrix of the shell of B. azoricus has little potential for use in environmental trace metal monitoring in areas contiguous to deep-sea hydrothermal vents. PMID:17291587

Cravo, A; Foster, P; Almeida, C; Company, R; Cosson, R P; Bebianno, M J

2007-07-01

27

Biogeography of hydrothermal vent communities along seafloor spreading centers.  

PubMed

Compared to terrestrial and shallow-water habitats, deep-sea hydrothermal vents are unique environments characterized by their local insularity, global distribution, individual ephemerality, collective geological longevity, geochemical homogeneity, and their physical and energetic isolation from the catastrophic events implicated in the extinction and speciation of terrestrial and shallow-water forms. Development of vent communities has thus occurred in novel biogeographical contexts that challenge our ability to understand evolutionary processes in the deep sea. Recent field work by French, Canadian, German, Japanese and American scientists has revealed intriguing patterns in the taxonomic composition and distribution of vent organisms at geographically disjunct study sites. PMID:21232364

Van Dover, C L

1990-08-01

28

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.

29

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

30

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

31

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

32

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

33

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

34

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

35

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

36

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

37

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

38

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

39

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

40

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

41

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

42

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

43

Using in situ voltammetry as a tool to identify and characterize habitats of iron-oxidizing bacteria: from fresh water wetlands to hydrothermal vent sites.  

PubMed

Iron-oxidizing bacteria (FeOB) likely play a large role in the biogeochemistry of iron, making the detection and understanding of the biogeochemical processes FeOB are involved in of critical importance. By deploying our in situ voltammetry system, we are able to measure a variety of redox species, specifically Fe(ii) and O2, simultaneously. This technique provides significant advantages in both characterizing the environments in which microaerophilic FeOB are found, and finding diverse conditions in which FeOB could potentially thrive. Described here are four environments with different salinities [one fresh groundwater seep site, one beach-groundwater mixing site, one hydrothermal vent site (Mid-Atlantic Ridge), and one estuary (Chesapeake Bay)] where in situ voltammetry was deployed, and where the presence of FeOB were confirmed by either culturing methods or molecular data. The sites varied in both O2 and Fe(ii) content with O2 ranging from below the 3 ?M detection limit of the electrodes at the Chesapeake Bay suboxic zone, to as high 150 ?M O2 at the vent site. In addition, a range of Fe(ii) concentrations supported FeOB communities, from 3 ?M Fe(ii) in the Chesapeake Bay to 300 ?M in the beach aquifer. In situ electrochemistry provides the means to quickly measure these redox gradients at appropriate resolution, making it possible in real time to detect niches likely inhabited by microaerophilic FeOB, then accurately sample for proof of FeOB presence and activity. This study demonstrates the utility of this approach while also greatly expanding our knowledge of FeOB habitats. PMID:24924809

MacDonald, Daniel J; Findlay, Alyssa J; McAllister, Sean M; Barnett, Josh M; Hredzak-Showalter, Patricia; Krepski, Sean T; Cone, Shane G; Scott, Jarrod; Bennett, Sarah K; Chan, Clara S; Emerson, David; Luther Iii, George W

2014-09-20

44

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

45

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

46

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

47

ORIGINAL ARTICLE Ultra-diffuse hydrothermal venting supports  

E-print Network

ORIGINAL ARTICLE Ultra-diffuse hydrothermal venting supports Fe-oxidizing bacteria and massive University, Bellingham, WA, USA A novel hydrothermal field has been discovered at the base of Lo¯ihi Seamount seawater temperature, derives from a distal, ultra-diffuse hydrothermal source. FeMO Deep is expressed

Moyer, Craig

48

Discovery of abundant hydrothermal venting on the ultraslow-spreading Gakkel ridge in the Arctic Ocean.  

PubMed

Submarine hydrothermal venting along mid-ocean ridges is an important contributor to ridge thermal structure, and the global distribution of such vents has implications for heat and mass fluxes from the Earth's crust and mantle and for the biogeography of vent-endemic organisms. Previous studies have predicted that the incidence of hydrothermal venting would be extremely low on ultraslow-spreading ridges (ridges with full spreading rates <2 cm x yr(-1)-which make up 25 per cent of the global ridge length), and that such vent systems would be hosted in ultramafic in addition to volcanic rocks. Here we present evidence for active hydrothermal venting on the Gakkel ridge, which is the slowest spreading (0.6-1.3 cm x yr(-1)) and least explored mid-ocean ridge. On the basis of water column profiles of light scattering, temperature and manganese concentration along 1,100 km of the rift valley, we identify hydrothermal plumes dispersing from at least nine to twelve discrete vent sites. Our discovery of such abundant venting, and its apparent localization near volcanic centres, requires a reassessment of the geologic conditions that control hydrothermal circulation on ultraslow-spreading ridges. PMID:12529639

Edmonds, H N; Michael, P J; Baker, E T; Connelly, D P; Snow, J E; Langmuir, C H; Dick, H J B; Mhe, R; German, C R; Graham, D W

2003-01-16

49

Evidence for a chemoautotrophically based food web at inactive hydrothermal vents (Manus Basin)  

NASA Astrophysics Data System (ADS)

Hydrothermal vents are ephemeral systems. When venting shuts down, sulfide-dependent taxa die off, and non-vent taxa can colonize the hard substrata. In Manus Basin (Papua New Guinea), where hydrothermally active and inactive sites are interspersed, hydroids, cladorhizid sponges, barnacles, bamboo corals, and other invertebrate types may occupy inactive sites. Carbon and nitrogen isotopic compositions of animals occupying inactive sites are consistent with nutritional dependence on either chemoautotrophically or photosynthetically produced organic material, but sulfur isotopic compositions of these animals point to a chemoautotrophic source of sulfur from dissolved sulfide in vent fluids rather than sulfur derived from seawater sulfate through photosynthesis. Given that suspension-feeding and micro-carnivorous invertebrates are the biomass dominants at inactive sites, the primary source of chemoautotrophic nutrition is likely suspended particulates and organisms delivered from nearby active vents.

Erickson, K. L.; Macko, S. A.; Van Dover, C. L.

2009-09-01

50

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

51

Light at deep sea hydrothermal vents  

NASA Astrophysics Data System (ADS)

We usually think of the bottom of the sea as a dark environment, lit only by flashes of bioluminescent light. Discovery of light associated with geothermal processes at deep sea hydrothermal vents forces us to qualify our textbook descriptions of the seafloor as a uniformly dark environment. While a very dim glow emitted from high temperature (350) vents (black smokers) at mid-oceanic ridge spreading centers has been documented [Van Dover et al, 1988], the source of this light and its role, if any, in the evolution and adaptation of photobiochemical processes have yet to be determined. Preliminary studies indicate that thermal radiation alone may account for the glow ]Smith and Delaney, 1989] and that a novel photoreceptor in shrimp-colonizing black smoker chimneys may detect this glow [Van Dover et al., 1989; Pelli and Chamberlain, 1989]. A more controversial question, posed by C. L. Van Dover, J. R. Cann, and J. R. Delaney at the 1993 LITE Workshop at the Woods Hole Oceanographic Institution in Massachusetts, is whether there may be sufficient light of appropriate wavelengths to support geothermally driven photosynthesis by microorganisms.

Van Dover, Cindy Lee; Cann, J. R.; Cavanaugh, Colleen; Chamberlain, Steven; Delaney, John R.; Janecky, David; Imhoff, Johannes; Tyson, J. Anthony

52

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

53

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

54

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

55

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

56

Macrofauna of shallow hydrothermal vents on the Arctic Mid-Ocean Ridge at 71N  

NASA Astrophysics Data System (ADS)

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. Specialized vent fauna includes various animal phyla, but the most conspicuous and well known are annelids, mollusks and crustaceans. We have investigated the fauna collected around newly discovered hydrothermal vents on the Mohns Ridge north of Jan Mayen. The venting fields are located at 71N and the venting takes place within two main areas separated by 5 km. The shallowest vent area is at 500-550 m water depth and is located at the base of a normal fault. This vent field stretches approximately 1 km along the strike of the fault, and it is composed of 10-20 major vent sites each with multiple chimney constructions discharging up to 260C hot fluids. A large area of diffuse, low- temperature venting occurs in the area surrounding the high-temperature field. Here, partly microbial mediated iron-oxide-hydroxide deposits are abundant. The hydrothermal vent sites do not show any high abundance of specialized hydrothermal vent fauna. Single groups (i.e. Porifera and Mollusca) have a few representatives but groups otherwise common in hydrothermal vent areas (e.g. vestimentifera, Alvinellid worms, mussels, clams, galathaeid and brachyuran crabs) are absent. Up until now slightly more than 200 species have been identified from the vent area. The macrofauna found in the vent area is, with few exceptions, an assortment of bathyal species known in the area. One endemic, yet undescribed, species of mollusc has been found so far, an gastropod related to Alvania incognita Warn, 1996 and A. angularis Warn, 1996 (Rissoidae), two species originally described from pieces of sunken wood north and south of Iceland. It is by far the most numerous mollusc species at the vents and was found on smokers, in the bacterial mats, and on the ferric deposits. A single specimen of an undescribed tanaidacean has also ben found. The crinoid Heliometra glacialis is dominating large areas surrounding the vent fields. Calcareous sponges were common in the area. Calcareous sponges normally represent only a minor fraction of the sponge fauna and it was therefore a big surprise that eight out of a total of 13 species reported here are calcareans. Annelids were the most speciose group with more than 80 identified species, followed by crustaceans. Possible explanations for the lack of typical vent fauna is discussed.

Schander, C.; Rapp, H. T.; Pedersen, R. B.

2007-12-01

57

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

58

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

PubMed

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

59

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

60

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

61

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

62

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

63

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

64

First Survey For Submarine Hydrothermal Vents In NE Sulawesi, Indonesia  

NASA Astrophysics Data System (ADS)

The IASSHA-2001 cruise (Indonesia-Australia Survey for Submarine Hydrothermal Activity) was successfully conducted from June 1 to June 29 on board Baruna Jaya VIII. Preliminary results are reported of the first expedition to locate and study submarine hydrothermal activity in north east Sulawesi. Leg A focussed on Tomini Bay, a virtually unexplored Neogene sedimentary basin. Its objective was to test whether modern sediment-hosted hydrothermal activity occurred on the sea floor. The results of new bathymetric mapping, sediment coring and CTD/transmissometer hydrocasts negate the likely presence in central Tomini Bay of large-scale modern analogues of hydrothermal massive sulfide environments involving hydrothermal venting of basinal or magma-derived fluids into reduced sediments. It is possible that the "heat engine" required to drive circulation of basinal and hydrothermal fluids is today too weak. Surveys around Colo volcano indicate that it may be in its final stage of evolution. Leg B studied the arc and behind-arc sectors of the Sangihe volcanic island chain extending northwards from Quaternary volcanoes on the northeastern tip of Sulawesi's North Arm, near Manado. West of the main active chain and extending northwards from Manado there is a subparallel ridge surmounted by a number of high (>2000 m) seamounts of uncertain age. Fifteen relatively high-standing submarine edifices were crossed during this leg, of which nine were tested for hydrothermal activity by hydrocast and dredging. Eight sites were known from previous bathymetric surveys, and seven are new discoveries made by narrow-beam or multibeam echo sounding. Two submarine edifices at least 1000 m high were discovered in the strait immediately north of Awu volcano on Sangihe Island. One, with crest at 206 m, is surrounded by a circular platform 300m deep which we infer to be a foundered fringing reef to a formerly emergent island. The other, lacking such a platform, appears relatively young and may be parasitic to Awu volcano. It has a summit crater or small caldera, about 800 m across and breached to the northwest. A dredge hauled within the caldera returned numerous un-abraded fragments of fresh pumiceous dacite glass with prominent phenocrysts of plagioclase, orthopyroxene and clinopyroxene, plus small angular fragments of a similar but less vesicular lithology. Coatings of soft ferruginous deposit on some fragments suggest that the caldera is hydrothermally active. A highlight of the expedition was a visit to Banua Wuhu, classed as an active volcano (eruption in 1919) whose summit is just exposed at low tide. Gas bubbling, subsurface sonic activity, and venting of hydrothermal fluids with temperatures around 50C are known to occur on the summit at around 10 m depth, and ferruginous oxide deposits several mm thick are common. A multibeam bathymetric chart to 1000 m was prepared and deeper narrow-beam echo sounding show that Banua Wuhu is a parasitic feature on the north-western side of adjacent Mahenetang Island, also a volcanic construction, the combined edifice exceeding 3000 m in height. We recovered thoroughly altered porphyritc andesite containing disseminated pyrite and a carbonate-chlorite-clay mineral assemblage. In summary, while the IASSHA cruise located only a single but potentially significant example of modern seafloor hydrothermal activity, we collected much valuable new geological and oceanographic data on two contrasted areas in northeastern Sulawesi that with on going post-cruise processing will greatly expand our knowledge of these regions. Binns and Permana Co-Chief Scientists

McConachy, T.; Binns, R.; Permana, H.

2001-12-01

65

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

66

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

67

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

68

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

69

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

70

A ubiquitous thermoacidophilic archaeon from deep-sea hydrothermal vents.  

PubMed

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 degrees C. In addition, we demonstrate that this isolate constitutes up to 15% of the archaeal population, providing evidence that thermoacidophiles may be key players in the sulphur and iron cycling at deep-sea vents. PMID:16871216

Reysenbach, Anna-Louise; Liu, Yitai; Banta, Amy B; Beveridge, Terry J; Kirshtein, Julie D; Schouten, Stefan; Tivey, Margaret K; Von Damm, Karen L; Voytek, Mary A

2006-07-27

71

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

72

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

73

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

74

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.

75

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

76

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

77

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

78

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.

79

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

80

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

81

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

82

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

83

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

84

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

85

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

86

Biological colonization of new hydrothermal vents following an eruption on Juan de Fuca Ridge  

NASA Astrophysics Data System (ADS)

A recent eruption on CoAxial Segment of Juan de Fuca Ridge initiated hydrothermal conditions with rapid changes in water chemistry and growth of microbial communities. Vent animals recruited from distal sources within a year. One site with newly erupted lava attracted no animals to high-iron and low-sulphide conditions. However, sustained release of flocculent material at a second site suggests extensive subterranean microbial production; here, the dissolved sulphide/heat ratio peaked during the first year. The first larval recruits included vestimentiferans, alvinellid polychaetes and nemerteans; despite the small areal extent of venting, one-third of the regional vent species pool had arrived by 2 years. Near-optimal growth conditions and recruitment by many species continued in the centre of the system but several habitats went extinct within 2 years. Rapid response and exploitation by vent animals must be an important adaptation to such ephemeral conditions.

Tunnicliffe, Verena; Embley, Robert W.; Holden, James F.; Butterfield, David A.; Massoth, Gary J.; Juniper, S. Kim

1997-09-01

87

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

88

Variation in the hydrothermal vent clam, Calyptogen magnifica, at the Rose Garden vent on the Galapagos spreading center  

NASA Astrophysics Data System (ADS)

Calyptogena magnifica occupy a relatively restricted habitat at the Rose Garden hydrothermal vent site on the Galapagos Rift. These clams are found in areas with very low flow of vent water and gain exposure to hydrogen sulfide by inserting their well-vascularized foot into cracks that contain this flow. Vent water is undetectable around the siphons of many of the individuals, and they therefore probably take up sulfide through their foot, and oxygen and inorganic carbon through their gills. Age estimates indicate that the bulk of the recruitment of C. magnifica occured between 1971 and 1976. Isotopic evidence indicates that symbionts are the main source of both nutritional carbon and nitrogen for the clams, and that the symbionts assimilate both of these substrates from inorganic sources. Carbohydrate and protein in the clam soft tissues, as well as the elemental sulfur content of their gills, decrease with increasing clam size. There is only slight variation in most of the parameters measured, and none of the parameters show nearly the variation seen in the other hydrothermal vent bivalve, Bathymodiolus thermophilus. However, several parameters, such as ?13C, condition index, and some bacterial enzyme activities, vary significantly with habitat.

Fisher, C. R.; Childress, J. J.; Arp, A. J.; Brooks, J. M.; Distel, D. L.; Dugan, J. A.; Felbeck, H.; Fritz, L. W.; Hessler, R. R.; Johnson, K. S.; Kennicutt, M. C.; Lutz, R. A.; Macko, S. A.; Newton, A.; Powell, M. A.; Somero, G. N.; Soto, T.

1988-10-01

89

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.

90

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.

91

Accumulation of minerals and trace elements in biogenic mucus at hydrothermal vents  

NASA Astrophysics Data System (ADS)

We have found several mechanisms by which a hydrothermal vent organism enhances metal and metalloid deposition at vent sites. Mucus accumulations associated with an alvinellid polychaete worm at northeast Pacific vents were found to be unusually rich in elemental sulfur, sulfide minerals and trace elements. Mucus production by the worm may be a mechanism for both internal and external detoxification of accumulating metals. Analyses indicate that inorganic components accumulate in the mucus through secretion or precipitation of elemental sulfur, occlusion of mineral particles, and adsorption and complexation of soluble species by the organic matrix of the mucus. Mucus-aggregated minerals contribute to the mass of sulfide deposits forming at these vents, but their quantitative significance is not clear.

Juniper, S. K.; Thompson, J. A. J.; Calvert, S. E.

1986-03-01

92

Sulfide Oxidation across Diffuse Flow Zones of Hydrothermal Vents  

Microsoft Academic Search

The sulfide (H2S\\/HS?) that is emitted from hydrothermal vents begins to oxidize abiotically with oxygen upon contact with ambient bottom water,\\u000a but the reaction kinetics are slow. Here, using in situ voltammetry, we report detection of the intermediate sulfur oxidation\\u000a products polysulfides [$$ {\\\\text{S}}_{\\\\text{x}}^{2 - } $$] and thiosulfate [$$ {\\\\text{S}}_{ 2} {\\\\text{O}}_{ 3}^{ 2- } $$], along with contextual

Amy Gartman; Mustafa Ycel; Andrew S. Madison; David W. Chu; Shufen Ma; Christopher P. Janzen; Erin L. Becker; Roxanne A. Beinart; Peter R. Girguis; George W. Luther

2010-01-01

93

Brachiopods from Ancient Hydrocarbon Seeps and Hydrothermal Vents  

Microsoft Academic Search

\\u000a Brachiopods are well-established as components of ancient chemosynthesis-dominated environments: hydrocarbon seeps and hydrothermal\\u000a vents. The focus here is primarily on brachiopods recorded from hydrocarbon seeps from the Palaeozoic and Mesozoic although\\u000a records from the Cenozoic are being reported. In hydrocarbon seeps brachiopods have played a central role forming shell-beds\\u000a that may be a few meters in vertical thickness and up

Michael R. Sandy

94

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.

95

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

96

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

97

Variation in physiological indicators in Bathymodiolus azoricus (Bivalvia: Mytilidae) at the Menez Gwen Mid-Atlantic Ridge deep-sea hydrothermal vent site within a year.  

PubMed

Bathymodiolus azoricus, thriving at Mid-Atlantic Ridge deep vents, benefits from a symbiosis with methane- and sulphide-oxidising (MOX and SOX) bacteria, and feeds on particulate and dissolved organic matter. To investigate the temporal evolution in their nutrition adult mussels were collected from one location at the Menez Gwen vent site (817 m depth) on four occasions between 2006 and 2007 and studied using different techniques, including stable isotope analyses and FISH. Gill and mantle tissues delta13C and delta15N signatures varied by 2-3 per thousand during the year and these variations were linked to fluctuations in tissue condition index, C and N contents and SOX/MOX volume ratios as quantified by 3D-FISH. October and January mussels presented a particularly poor condition, possibly related with the prolonged summer period of low sea-surface primary production and/or with the stress of the transplant to acoustically retrievable cages for the October mussels, and with their reproductive state in January mussels, since they were spawning. Our results point to the possibility that May mussels benefited from a pulse of sinking sea-surface plankton material. Results underline the dependency of stable isotopic signatures on the physiological state of the mussel at the time of collection, and on the type of tissue analyzed. PMID:20605205

Riou, Virginie; Duperron, Sbastien; Halary, Sbastien; Dehairs, Frank; Bouillon, Steven; Martins, Ins; Colao, Ana; Serro Santos, Ricardo

2010-01-01

98

Biodiversity and biogeography of hydrothermal vent species in the western Pacific: a biological perspective of TAIGA project  

NASA Astrophysics Data System (ADS)

Deep-sea hydrothermal vents are scientifically interesting environments where strong interactions of geology, chemistry, and biology can be observed. The hydrothermal vents are geologically controlled in association with magmatic activities while diversity of chemicals (such as hydrogen sulfide) contained in hydrothermal fluid is controlled by geochemical interaction between heated seawater and surrounding rocks. In addition to those geological and chemical characters of hydrothermal vents, high biomasses of chemosynthetic community have been known around many vents since the first discovery in the 1970s. To understand the unique system and diversity of biological communities associated with vents is highly valuable in geological, chemical, and biological sciences. As an activity of the research project "TAIGA (Trans-crustal Advection & In-situ bio-geochemical processes of Global sub-seafloor Aquifer)" (Representative: Tetsuro Urabe, Department of Earth & Planetary Science, the University of Tokyo), we analyzed population structures and connectivity as well as larval ecology of various hydrothermal vent species in the Okinawa Trough and the Mariana Trough in an attempt to estimate faunal transitional history associated with hydrothermal activities. The specimens analyzed in the present study were collected by R/V Yokosuka with manned submersible Shinkai6500 and R/V Natsushima with ROV Hyper-Dolphin during YK10-11 and NT11-20 cruises, respectively. In the Mariana Trough (YK10-11), benthic and planktonic faunas were investigated by multiple sampling and use of plankton samplers in three hydrothermal vents (Snail, Archaean, and Urashima-Pika fields). Faunal compositions were then compared as well as size compositions and genetic diversities of major vent species among local populations. In the Okinawa Trough (NT11-20), multiple quantitative sampling was made with simultaneous environmental measurements at more than two sites in five hydrothermal vents (Minami-Ensei Knoll, Yoron Knoll, Izena Hole, Irabu Knoll, and Hatoma Knoll). Among the local populations, biodiversities were analyzed and compared in consideration of abiotic environmental factors including temperature and chemical compositions. Ecological aspects of larvae were examined by laboratory experiments in addition to the genetic approaches and population dynamics. Preliminary results of the ongoing studies suggested that the biodiversity of vents may be consistent with geographical history. By accumulating results of diversified approaches, we progress our study to reveal not only biological characters but also geological and chemical aspects of those hydrothermal vents.

Seo, M.; Watanabe, H.; Nakamura, M.; Sasaki, T.; Ogura, T.; Yahagi, T.; Takahashi, Y.; Ishibashi, J.; Kojima, S.

2012-12-01

99

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

100

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.

101

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

102

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

103

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

104

First survey of sessile communities on subtidal rocks in an area with hydrothermal vents: Milos Island, Aegean Sea  

Microsoft Academic Search

The major epibenthic communities on subtidal rocks of Palaeochori Bay and the marine tract on the southern coast of Milos Island (Greece) were described down to 44 m depth. Six sites were investigated by snorkelling and SCUBA diving. Samples, photographs and video images were also taken to integrate information. Three out of the six sites were close to hydrothermal vents,

Silvia Cocito; C. Nike Bianchi; Carla Morri; Andrea Peirano

2000-01-01

105

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

106

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

107

Video Observations by Telepresence Reveal Two Types of Hydrothermal Venting on Kawio Barat Seamount  

NASA Astrophysics Data System (ADS)

The INDEX-SATAL 2010 expedition began an international exploration of the seafloor in Indonesian waters using the methodology of telepresence, conducting EM302 multibeam mapping, water column CTD, and ROV high-definition video operations and sending data back to Exploration Command Centers in Indonesia and Seattle. Science observers in other locations in the US and Canada were engaged in real-time observations and interpretation of results. One mission goal was to locate hydrothermal or volcanic activity. Intense light scattering and redox potential measurements in the water column over Kawio Barat (KB)indicated a high level of hydrothermal activity, and direct video observations confirmed venting near the summit. None of the other volcanic features west of the Sangihe arc that were investigated during the mission had confirmed hydrothermal activity. ROV capabilities did not include physical sampling or temperature measurement, so our interpretation is based on visual comparison to other known sites. The steep western flank of KB from 2000 m depth to the summit (1850 m) has many areas of white and orange staining on exposed rocks, with some elemental sulfur, and broad areas covered with dark volcaniclastic sand, but no active venting was seen. KB has a summit ridge running WNW-ESE, with a major cross-cutting ridge on the western portion of the summit. Hydrothermal activity is concentrated near the eastern side of this intersection, on both the northern and southern sides of the summit ridge. Venting on the northern side of the summit ridge is characterized by intense white particle-rich fluids emanating directly from the rocky substrate with frozen flows of elemental sulfur down slope. This type of venting is visually very similar to the venting seen on NW Rota-1, an actively erupting volcano in the Mariana arc, and suggests that KB is actively releasing magmatic gases rich in sulfur dioxide to produce the elemental sulfur flows, inferred fine particulate sulfur particles, and apparent acidic alteration. These hydrothermal features along with the widespread occurrence of volcaniclastic deposits near the summit suggest that Kawio Barat has experienced recent eruptive activity. In contrast, however, the south side of the summit has active metal sulfide chimneys venting clear to gray/black fluids. The vents seen on the south slope appear identical to vents detected by camera tow and reported by McConnachy et al. 2004. The visually dominant vent fauna is a stalked barnacle that covers much of the chimney surfaces. The apparently stable hot vents on the south flank require a reaction zone with low water/rock ratio at depth within the volcano. Some aspect of the volcanic/hydrothermal plumbing at KB produces a separation of magmatic gases (north summit slope) from circulating hydrothermal fluids (south summit slope).

Butterfield, D. A.; Holden, J. F.; Shank, T. M.; Tunnicliffe, V.; Sherrin, J.; Herrera, S.; Baker, E. T.; Lovalvo, D.; Makarim, S.; Malik, M. A.; Wirasantosa, S.; Hammond, S. R.

2010-12-01

108

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

109

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

110

Organic Complexing in Smectite Clay Minerals Under Hydrothermal Vent Conditions  

NASA Astrophysics Data System (ADS)

A hydrothermal vent at the Juan de Fuca ridge was found to contain smectite-rich clay minerals. At vent fluid temperatures (300-350C) smectite quickly reacts to form more stable minerals, such as illite or chlorite, by incorporating metal cations. While similar investigations have assigned the catalytic properties of clays strictly to the surfaces, it is our hypothesis that organic molecules are polymerized in the smectite interlayers during reaction. Upon incorporation of metal cations and primary organic molecules in the expandable interlayer of these clays, gradual changes in the electrochemical environment may catalyze bio-oligomers that are essential components of life. For comparison, we have examined both dioctahedral (montmorillonite; SWy-1) and trioctahedral (saponite) smectite clay minerals which react to illite and chlorite, respectively. An illite standard (IMt-1) has also been examined as a catalyst. Progressive steps in the reaction process have been monitored through hydrothermal experimentation simulating seafloor and subseafloor volcanic conditions in welded gold capsules. K-saturated smectite clays were reacted with aqueous 10 M methanol solutions up to six weeks. Reaction progress was monitored weekly. Results suggest that organic complexity increases as a function of mineralogical reaction. While producing some similar complex organic compounds, reactions starting with illite yielded significantly lower product concentrations than those with the smectites, suggesting the expandable interlayers play an important role in catalysis. Organic analyses were performed by GC-MS; clay analyses by x-ray diffraction.

Canfield, B. M.; Williams, L. B.; Holloway, J. R.

2002-12-01

111

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

112

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

113

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

114

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

115

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

116

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

117

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

118

Chemistry of a serpentinization-controlled hydrothermal system at the Lost City hydrothermal vent field  

NASA Astrophysics Data System (ADS)

The Lost City Hydrothermal Field (LCHF), at 30 N near the Mid-Atlantic Ridge, is an off-axis, low temperature, high-pH, ultramafic-hosted vent system. Within the field, carbonate chimneys tower up to 60 m above the seafloor, making them the tallest vent structures known. The chemistry of the vent structures and fluids at the LCHF is controlled by reactions between seawater and ultramafic rocks beneath the Atlantis massif. Mixing of warm alkaline vent fluids with seawater causes precipitation of calcium carbonate and growth of the edifaces, which range from tall, graceful pinnacles to fragile flanges and colloform deposits. Geochemical and petrological analyses of the carbonate rocks reveal distinct differences between the active and extinct structures. Actively venting chimneys and flanges are extremely porous, friable formations composed predominantly of aragonite and brucite. These structures provide important niches for well-developed microbial communities that thrive on and within the chimney walls. Some of the active chimneys may also contain the mineral ikaite, an unstable, hydrated form of calcium carbonate. TIMS and ICP-MS analyses of the carbonate chimneys show that the most active chimneys have low Sr isotope values and that they are low in trace metals (e.g., Mn, Ti, Pb). Active structures emit high-pH, low-Mg fluids at 40-90 C. The fluids also have low Sr values, indicating circulation of hydrothermal solutions through the serpentinite bedrock beneath the field. In contrast to the active structures, extinct chimneys are less porous, are well lithified, and they are composed predominantly of calcite that yields Sr isotopes near seawater values. Prolonged lower temperature seawater-hydrothermal fluid interaction within the chimneys results in the conversion of aragonite to calcite and in the enrichment of some trace metals (e.g., Mn, Ti, Co, Zn). It also promotes the incorporation of foraminifera within the outer, cemented walls of the carbonate structures. The Lost City system represents a novel natural laboratory for observing hydrothermal and biological activity in a system controlled by moderate temperature serpentinization reactions. The LCHF is the only vent field of its kind known to date; however, it is likely not unique along the global mid-ocean ridge spreading network.

Ludwig, K. A.; Kelley, D. S.; Butterfield, D. A.; Nelson, B. K.; Karson, J. A.

2003-12-01

119

The spatial scale of genetic subdivision in populations of Ifremeria nautilei, a hydrothermal-vent gastropod from the southwest Pacific  

PubMed Central

Background Deep-sea hydrothermal vents provide patchy, ephemeral habitats for specialized communities of animals that depend on chemoautotrophic primary production. Unlike eastern Pacific hydrothermal vents, where population structure has been studied at large (thousands of kilometres) and small (hundreds of meters) spatial scales, population structure of western Pacific vents has received limited attention. This study addresses the scale at which genetic differentiation occurs among populations of a western Pacific vent-restricted gastropod, Ifremeria nautilei. Results We used mitochondrial and DNA microsatellite markers to infer patterns of gene flow and population subdivision. A nested sampling strategy was employed to compare genetic diversity in discrete patches of Ifremeria nautilei separated by a few meters within a single vent field to distances as great as several thousand kilometres between back-arc basins that encompass the known range of the species. No genetic subdivisions were detected among patches, mounds, or sites within Manus Basin. Although I. nautilei from Lau and North Fiji Basins (~1000 km apart) also exhibited no evidence for genetic subdivision, these populations were genetically distinct from the Manus Basin population. Conclusions An unknown process that restricts contemporary gene flow isolates the Manus Basin population of Ifremeria nautilei from widespread populations that occupy the North Fiji and Lau Basins. A robust understanding of the genetic structure of hydrothermal vent populations at multiple spatial scales defines natural conservation units and can help minimize loss of genetic diversity in situations where human activities are proposed and managed. PMID:22192622

2011-01-01

120

Unusual geochemistry of hydrothermal vents on submarine arc volcanoes: Kasuga Seamounts, Northern Mariana Arc  

Microsoft Academic Search

DSRV Alvin dives in the Northern Mariana island arc recovered warm hydrothermal fluids from the summit areas of seamounts Kasuga 2 and Kasuga 3, as well as hydrothermal deposits of elemental sulfur, Fe- and Mn-oxides, and nontronite. The composition of a gas-rich ~ 39C vent fluid sampled from Kasuga 2 Seamount is unusual compared to other submarine hydrothermal fluids in

G. M. McMurtry; P. N. Sedwick; P. Fryer; D. L. Vonderhaar; H.-W. Yeh

1993-01-01

121

Identification of 16S Ribosomal DNA-Defined Bacterial Populations at a Shallow Submarine Hydrothermal Vent near Milos Island (Greece)  

PubMed Central

In a recent publication (S. M. Sievert, T. Brinkhoff, G. Muyzer, W. Ziebis, and J. Kuever, Appl. Environ. Microbiol. 65:38343842, 1999) we described spatiotemporal changes in the bacterial community structure at a shallow-water hydrothermal vent in the Aegean Sea near the isle of Milos (Greece). Here we describe identification and phylogenetic analysis of the predominant bacterial populations at the vent site and their distribution at the vent site as determined by sequencing of DNA molecules (bands) excised from denaturing gradient gels. A total of 36 bands could be sequenced, and there were representatives of eight major lineages of the domain Bacteria. Cytophaga-Flavobacterium and Acidobacterium were the most frequently retrieved bacterial groups. Less than 33% of the sequences exhibited 90% or more identity with cultivated organisms. The predominance of putative heterotrophic populations in the sequences retrieved is explained by the input of allochthonous organic matter at the vent site. PMID:10877814

Sievert, Stefan M.; Kuever, Jan; Muyzer, Gerard

2000-01-01

122

Identification of 16S ribosomal DNA-defined bacterial populations at a shallow submarine hydrothermal vent near Milos Island (Greece).  

PubMed

In a recent publication (S. M. Sievert, T. Brinkhoff, G. Muyzer, W. Ziebis, and J. Kuever, Appl. Environ. Microbiol. 65:3834-3842, 1999) we described spatiotemporal changes in the bacterial community structure at a shallow-water hydrothermal vent in the Aegean Sea near the isle of Milos (Greece). Here we describe identification and phylogenetic analysis of the predominant bacterial populations at the vent site and their distribution at the vent site as determined by sequencing of DNA molecules (bands) excised from denaturing gradient gels. A total of 36 bands could be sequenced, and there were representatives of eight major lineages of the domain Bacteria. Cytophaga-Flavobacterium and Acidobacterium were the most frequently retrieved bacterial groups. Less than 33% of the sequences exhibited 90% or more identity with cultivated organisms. The predominance of putative heterotrophic populations in the sequences retrieved is explained by the input of allochthonous organic matter at the vent site. PMID:10877814

Sievert, S M; Kuever, J; Muyzer, G

2000-07-01

123

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

124

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

125

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

126

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

127

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

128

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

129

Sulfide Oxidation across Diffuse Flow Zones of Hydrothermal Vents  

NASA Astrophysics Data System (ADS)

Both diffuse flow and high temperature hydrothermal vents emit large quantities of reduced sulfur, largely in the form of H2S. Sulfide oxidation may begin upon contact with ambient bottom water. Here, using in situ voltammetry, we report detection of intermediate sulfur oxidation products including polysulfides [Sx2-], which can decompose to elemental sulfur [S8], and thiosulfate [S2O32-]. Nearly four percent of the 11,000 individual voltammetric scans taken at four vent areas at Lau Basin in May 2009 contained either thiosulfate or polysulfides. Previous work at the East Pacific Rise (EPR) has identified these species, but in a statistically insignificant number of scans. At Lau Basin in 2006, thiosulfate was identified in less than one percent of scans, and no polysulfides were conclusively detected. Here we review sulfide, temperature and sulfur oxidation intermediate data from Lau Basin, obtained in 2006 and 2009. We also review the thermodynamics of the first electron transfer steps for sulfide and oxygen and the possible need for iron and/or manganese in a catalytic cycle during sulfide oxidation in these systems.

Gartman, A.; Yucel, M.; Madison, A.; Janzen, C.; Ma, S.; Luther, G. W.

2010-12-01

130

GALREX 2011: Extensive hydrothermal venting discovered along the eastern Galpagos Rift  

NASA Astrophysics Data System (ADS)

Leg 1 of the Galpagos Rift Expedition (GALREX) on the NOAA Ship Okeanos Explorer, July 2011, conducted a 400-km-long continuous CTD transect to map active hydrothermal areas between 89.33 and 87.75W. Light backscattering (?NTU) and oxidation-reduction potential (ORP) sensors measured the relative concentration of suspended particles and reduced hydrothermal chemicals, respectively. GALREX was designed to complement a similar survey in 2005/2006 that surveyed the central Galpagos Rift from 94.9 to 89.6W. That survey found only two active high-temperature vent fields, plus robust plume evidence for at least six smaller fields. The spatial density of hydrothermal plumes (ph) along the rift was only 0.11 (based on ?NTU anomalies), significantly less than expected for intermediate-rate (50-60 mm/yr) spreading but similar to other hotspot-affected ridges (e.g., near the Iceland, Ascension, and St. Paul-Amsterdam hotspots). This low ph value was hypothesized to be an expression of (1) reduced hydrothermal discharge on ridge sections with hotspot-thickened crust, (2), widespread low-temperature discharge undetectable by large-scale surveys, or (3) episodic venting. GALREX found a distinctly different hydrothermal environment on the eastern third of the rift. Overall, ph = 0.19, about twice that of the central Galpagos Rift. Strong venting was concentrated in two areas. Most remarkable was a 50-km-long section (88.56-88.09W) where continuous plumes with high (>0.2) ?NTU values rose as high as 250 m above the seafloor. This area is low amplitude valley and ridge topography, centered on a relatively recent lava flow at 88.33W. The second area included the historical vent fields Rose Garden and Rosebud, and ranged from 86.25 to 85.87W. In this area ?NTU was lower (~0.1) and plumes were patchy. ORP anomalies occasionally occurred in the absence of ?NTU anomalies, suggesting low-temperature, particle-poor vent sources. No anomalies were detected over the Rose Garden/Rosebud sites. The entire GALREX survey detected ~20 discrete ORP anomalies, with along-axis separations ranging from 2 to 110 km (median=14 km). Because ORP anomalies are very short lived, and thus do not advect far from their seafloor source, at least ~20 distinct vent "fields" must be active, a higher spatial frequency than found along the central Galpagos Rift. The eastern rift section is also notable for supporting two areas of extensive venting, each >40 km along axis, and each paved by apparently young (~10 yr) lavas. Each of these areas is ~3x longer than the longest hydrothermal area on the central rift section.

Baker, E. T.; Walker, S. L.; White, S. M.; Embley, R. W.; Resing, J. A.; Lobecker, M.

2011-12-01

131

Presence and activity of anaerobic ammonium-oxidizing bacteria at deep-sea hydrothermal vents.  

PubMed

Recent studies indicate that ammonia is an important electron donor for the oxidation of fixed nitrogen, both in the marine water column and sediments. This process, known as anammox, has so far only been observed in a large range of temperature habitats. The present study investigated the role of anammox in hydrothermal settings. During three oceanographic expeditions to the Mid-Atlantic Ridge, hydrothermal samples were collected from five vent sites, at depths ranging from 750 to 3650 m from cold to hot habitats. Evidence for the occurrence of anammox in these particular habitats was demonstrated by concurrent surveys, including the amplification of 16S rRNA gene sequences related to known anammox bacteria, ladderanes lipids analysis and measurement of a (14)N(15)N dinitrogen production in isotope-pairing experiments at 60 and 85 degrees C. Together these results indicate that new deep-branching anammox bacteria may be active in these hot habitats. PMID:18670398

Byrne, Nathalie; Strous, Marc; Crpeau, Valentin; Kartal, Boran; Birrien, Jean-Louis; Schmid, Markus; Lesongeur, Franoise; Schouten, Stefan; Jaeschke, Andrea; Jetten, Mike; Prieur, Daniel; Godfroy, Anne

2009-01-01

132

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

133

An Approach to Mimicking Abiotic Hydrogenation of Carbon Dioxide in Alkaline Hydrothermal Vents  

NASA Astrophysics Data System (ADS)

A microfludic approach is considered to determine whether the natural proton-motive and chemiosmotic forces seen in alkaline hydrothermal vents were purely coincidental or if they had a real bearing on how life emerged.

Wade, L. A.; Fraser, S.; Haile, S.; Collier, P.

2010-04-01

134

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

135

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.

136

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

137

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

138

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

139

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

140

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

141

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

142

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

143

Study of Hydrothermal Particulate Matter from a Shallow Venting System, offshore Nayarit, Mexico  

NASA Astrophysics Data System (ADS)

A shallow (30 ft) hydrothermal site named ``Cora'' (after the indigenous people thereby) was surveyed and sampled throughout direct observation with SCUBA diving during November 25 to December 4, 2000. A total of 10 dives were conducted in order to obtain representative samples from an 85oC fluid source of approximately 10 cm in diameter. Inherent difficulties to the sampling, such as poor visibility and strong bottom currents were overcome and samples of hydrothermal fluid, gas, rocks, and particulate matter were collected directly from the vent. Water samples and hydrothermal fluid were taken with a homemade 1 l cylindrical bottles of two lines by flushing in from the bottom for about ten minutes until total displacement of the seawater; similar procedure was carried out for gas samples. Particulate matter was collected with 0.4mm polycarbonate membrane filters and preserved in a desiccators at a fridge temperature until analysis onshore. Preliminary description of the rock samples suggest that pyritization is the main mineralisation process. Filters containing hydrothermal particulate matter were surveyed under the scanning electron microscope in order to identify the nature (inorganic and organic), as well as the chemistry of the particles. SEM examination revealed the presence of particles of different kind that suggests high degree of mixing and re-suspension: Planctonic organisms and organic matter appeared to be abundant; 25 micron particles of different carbonate faces and inorganic particles of silicates were also recognized. Distinctive euhedral colloidal grains were identified as the resulting process of precipitation from the solution. Microanalysis of iron and sulfur content of 10 micron particles indicate a very likely sulphide mineral face (greigite); 8 micron cinnabar particles are consistent with the mineralization conditions, observed as well in the inner walls of the vent. Analyses of dissolved and particulate trace metals are still ongoing at labs in New Zealand and Mexico and will be incorporated in a near future.

Ortega-Osorio, A.; Prol-Ledesma, R. M.; Reyes, A. G.; Rubio-Ramos, M. A.; Torres-Vera, M. A.

2001-12-01

144

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

145

Sources of REE in sediment cores from the Rainbow vent site (3614?N, MAR)  

Microsoft Academic Search

A geochemical investigation was carried out on two sediment cores collected at 2 and 5 km from the Rainbow hydrothermal vent site. Bulk sediment compositions indicate that these cores record clear enrichments in Fe, Cu, Mn, V, P and As from hydrothermal plume fallout (Cave et al., 2002) [Cave, R.R., German, C.R., Thomson, J., Nesbitt, R.W., 2002. Fluxes to sediments

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

2005-01-01

146

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

147

Life in the extreme environment at a hydrothermal vent: haemoglobin in a deep-sea copepod.  

PubMed Central

This is the first study, to my knowledge, quantifying the respiratory pigment haemoglobin discovered in a deep-sea copepod. Haemoglobin in copepods has previously been documented in only one other species from the deep water of an Italian lake. Specimens of the siphonostomatoid Scotoecetes introrsus Humes were collected during submersible dives at 2500 m depth near a hydrothermal vent at the East Pacific Rise (9 degrees N). The haemoglobin content in the copepods' haemolymph was 4.3 +/- 0.6 micrograms per individual female (n = 6) and 1.8 +/- 0.1 micrograms per individual male (n = 6). Weight-specific concentrations of haemoglobin were identical for females and males (0.25 +/- 0.04 and 0.26 +/- 0.02 microgram per microgram dry weight, respectively). These haemoglobin concentrations are higher than those found in other small crustaceans. Activity of the electron transport system indicated that the respiration rates in S. introrsus (13.7 +/- 7.7 microliters O2 per milligram dry weight per hour) were similar to those in the shallow-water copepod Acartia tonsa (9.1 +/- 1.3 microliters O2 per milligram dry weight per hour). It was concluded that the possession of highly concentrated haemoglobin allows S. introrsus to colonize a geologically young, thermally active site such as the vicinity of a hydrothermal vent, despite the prevailing oxygen depletion. PMID:11413650

Sell, A F

2000-01-01

148

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

149

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

150

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

151

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

152

Control of high-permeability faults on off-axis hydrothermal venting - a case study of Logatchev 1  

NASA Astrophysics Data System (ADS)

The off-axis Logatchev hydrothermal field at 1445'N at the Mid Atlantic Ridge consists of several vent sites in an ultramafic host rock environment. Here we focus on the Logatchev 1 site, which is located 8km off-axis. Hydrothermal fluids are discharging at 300-360C and a recent seismic study (Grevemeyer, 2013, G3) revealed intense off-axis seismic activity along a fault plane dipping towards the ridge axis. What is the role of this fault in controlling high temperature off-axis venting? Using numerical modeling we have studied the conditions that are required to establish high-temperature venting in an off-axis setting using Logatchev 1 as case study. We use a 2D FE model, which solves for hydrothermal convection of pure water beneath the seafloor. The model setup is instructed by geophysical data (bathymetry, fault location, depth of the heat source). We have systematically varied the position of the heat source as well as fault width and permeability. High-temperature venting at the seafloor near the known fault zone requires the driving heat source to be located between the region affected by faulting and the vent field. Only under these conditions, hydrothermal fluids are deviated from their vertical path to ascent along the highly permeable fault zone and exit at the known position of Logatchev 1. Vent temperatures are strongly controlled by the fault's permeability and width; increasing one of the parameters leads to decreased temperatures. Similar temperatures can be obtained when increasing fault width while decreasing fault permeability, or vice versa. Our results suggest that high vent temperatures of 360C 10C including a highly permeable fault zone could only be reached with two model set-ups: 1. a 15-40m wide fault zone that yields a permeability of 7x10-15 m2, an order of magnitude higher than the background (7x10-16 m2). 2. a lower fault permeability of 2x10-15 and a width of 100-150m If the fault is narrower than 15m or 100m for the respective permeabilities the ascending fluids cross it and continue to rise vertically and vent above the heat source rather than at the fault termination at the seafloor. If the fault is wider than 40m/150m, vent temperatures drop due to mixing with colder fluids. We explain this by the fluid mass flow within the fault: if the vertical mass flow rate inside the fault exceeds that of the hydrothermal plume entering the fault at depth, cold water from the surrounding is drawn into the fault, which leads to mixing and thus lower vent temperatures. The vent temperatures in all our calculations do not exceed ~370C, which is very close to the maximum observed temperature at Logatchev 1. This value may thus represent an upper limit for temperatures of hydrothermal systems that are associated with fault zones of higher permeability.

Andersen, C.; Rupke, L.; Grevemeyer, I.; Petersen, S.; Hasenclever, J.

2013-12-01

153

Sea Vent Viewer  

NSDL National Science Digital Library

This web site serves as an educational overview of National Science Foundation (NSF) earth and environmental science research focusing on hydrothermal vent systems. It features an interactive viewer which allows users to explore hydrothermal vent systems with the touch of a mouse. Dragging the cursor around the screen moves the field of view while clicking on numbered items reveals informational pages about each inhabitant.

National Science Foundation

154

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

155

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

156

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

157

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.

158

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

159

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

160

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

NASA Astrophysics Data System (ADS)

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 and noncultivated microbes, respectively. Of the 29 bacterial representative phylotypes, over one third of the SSU rRNA gene sequences retrieved belonged to uncultivated candidate divisions including OP1, OP3, OP5, OP8, OD1, and OP11. All archaeal phylotypes belonged to the phylum Euryarchaeota in the uncultivated groups deep hydrothermal vent euryarchaeotal (DHVE) I and II or to the phylum Korarchaeota. Like the bacterial clone library, only a small proportion of archaeal SSU rRNA gene sequences (2% and 20%) displayed >92% sequence identity with any archaeal isolates or noncultivated microbes, respectively. Although the bacterial phylotypes detected were phylogenetically most similar to microbial communities detected in methane, hydrocarbon, and carbon dioxide-based hydrothermal and seep environments, no phylotypes directly associated with anaerobic methane oxidation and mcrA activity could be detected. The geochemical composition of the vent fluids at the Brothers-lower cone sample site is unusual and we suggest that it may play a prominent role in the species selection of this microbial community.

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

2008-08-01

161

A Retrievable Mineral Microcosm for Examining Microbial Colonization and Mineral Precipitation at Seafloor Hydrothermal Vents  

NASA Astrophysics Data System (ADS)

Although seafloor hydrothermal vent environments are known to support thriving ecosystems, the microscale physical and chemical environment suitable for microbial colonization and the identity of pioneering organisms is unknown. Because of the fragility of young chimneys and their ephemeral nature, novel methods for sample retrieval and analysis are required. The mineral microcosm consists of four titanium mesh chambers containing crushed minerals mounted on a titanium base that allows for fluid flow through the chambers. The chambers can be filled with different minerals or mineral mixtures (or no minerals) to supply different substrates for microbial colonization and different local microenvironments as minerals react with the surrounding fluids. The device sets on top of an active hydrothermal vent for a period of days to weeks to allow colonization and mineral reaction. The mineral microcosm was deployed during the Atlantis/Alvin Extreme 2001 Cruise (Oct.- Nov.,2001) to 9 50'N on the East Pacific Rise a total of three times, for ~ 24, ~ 96, and ~ 48 hours each. It was deployed in two different environments, twice in lower temperature (<300C), diffuse-flow environments and once (for ~96 hours) in a higher temperature black smoker environment (>350C).Seed minerals included sulfides, sulfates, magnetite, apatite, and quartz, both individually and in mixtures. In the first 24-hour deployment, dissolution of anhydrite but not sulfide minerals within the chambers indicated high temperatures in chamber interiors and rapid reaction rates. Temperatures measured on chamber exteriors before retrieval ranged from 4 -98C. The 96-hour deployment on a hot vent (fluid ~370C before deployment) resulted in extensive mineral precipitation and chimney growth inside the mineral chambers, on the outer surfaces of the chambers, and on the platform as a whole, creating micro-chimneys several centimeters tall. The young chimneys were mainly composed of pyrite with lesser amounts of chalcopyrite and sphalerite and with thin veneers of anhydrite on exterior surfaces in contact with seawater. Bulk trace element analyses of the newly formed chimneys show concentrations of Ag, Cd, Co, Cr, Mo, Ni, and Pb (up to ~200 ppm) but a lack of As, Sn, U, and W. On the last deployment in a polychaete-rich, diffuse-flow area (vent temperature ~300C), the microcosm was covered with biofilm and polychaete tubes had formed on the surface during the ~48 hours on the vent. Temperatures at chamber exteriors had decreased to 16- 20C, suggesting that the vent was not vigorous enough to maintain a large flow through the chambers. Although no evidence for microbial colonization was obtained in these initial deployments, the device can simulate the mineralogy and temperature gradients of a natural hydrothermal chimney. Young chimney samples of known age (~96 hours) obtained from the second deployment were analyzed by synchrotron X-ray computed tomography for porosity and mineralogy and compared with existing chimneys at these sites (see companion abstract by Ashbridge, et al.).

Dunn, E. E.; Holloway, J. R.; Cary, S.; Voglesonger, K. M.; Ashbridge, D. A.; O'Day, P. A.

2002-12-01

162

Intracellular coexistence of methano- and thioautotrophic bacteria in a hydrothermal vent mussel.  

PubMed Central

The coexistence of two phylogenetically distinct symbiont species within a single cell, a condition not previously known in any metazoan, is demonstrated in the gills of a Mid-Atlantic Ridge hydrothermal vent mussel (family Mytilidae). Large and small symbiont morphotypes within the gill bacteriocytes are shown to be separate bacterial species by molecular phylogenetic analysis and fluorescent in situ hybridization. The two symbiont species are affiliated with thioautotrophic and methanotrophic symbionts previously found in monospecific associations with closely related mytilids from deep-sea hydrothermal vents and hydrocarbon seeps. Images Fig. 1 Fig. 3 PMID:7568180

Distel, D L; Lee, H K; Cavanaugh, C M

1995-01-01

163

Ammonificins C and D, Hydroxyethylamine Chromene Derivatives from a Cultured Marine Hydrothermal Vent Bacterium, Thermovibrio ammonificans  

PubMed Central

Chemical and biological investigation of the cultured marine hydrothermal vent bacterium, Thermovibrio ammonifican led to the isolation of two hydroxyethylamine chromene derivatives, ammonificins C and D. Their structures were elucidated using combination of NMR and mass spectrometry. Absolute stereochemistry was ascertained by comparison of experimental and calculated CD spectra. Biological evaluation and assessment were determined using the patented ApopScreen cell-based screen for apoptosis-induction. Ammonificins C and D induce apoptosis in micromolar concentrations. To our knowledge, this finding is the first report of chemical compounds that induce apoptosis from the cultured deep-sea marine organism, hydrothermal vent bacterium, Thermovibrio ammonificans. PMID:23170085

Andrianasolo, Eric H.; Haramaty, Liti; Rosario-Passapera, Richard; Vetriani, Costantino; Falkowski, Paul; White, Eileen; Lutz, Richard

2012-01-01

164

Virioplankton and bacterioplankton in a shallow CO 2-dominated hydrothermal vent (Panarea Island, Tyrrhenian Sea)  

NASA Astrophysics Data System (ADS)

Gas hydrothermal vents are used as a natural analogue for studying the effects of CO 2 leakage from hypothetical shallow marine storage sites on benthic and pelagic systems. This study investigated the interrelationships between planktonic prokaryotes and viruses in the Panarea Islands hydrothermal system (southern Tyrrhenian Sea, Italy), especially their abundance, distribution and diversity. No difference in prokaryotic abundance was shown between high-CO 2 and control sites. The community structure displayed differences between fumarolic field and the control, and between surface and bottom waters, the latter likely due to the presence of different water masses. Bacterial assemblages were qualitatively dominated by chemo- and photoautotrophic organisms, able to utilise both CO 2 and H 2S for their metabolic requirements. From significantly lower virioplankton abundance in the proximity of the exhalative area together with particularly low Virus-to-Prokaryotes Ratio, we inferred a reduced impact on prokaryotic abundance and proliferation. Even if the fate of viruses in this particular condition remains still unknown, we consider that lower viral abundance could reflect in enhancing the energy flow to higher trophic levels, thus largely influencing the overall functioning of the system.

Karuza, Ana; Celussi, Mauro; Cibic, Tamara; Del Negro, Paola; De Vittor, Cinzia

2012-01-01

165

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

166

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

167

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

168

Evidence for a Chemoautotrophically Based Food Web at Inactive Hydrothermal Vents (Manus Basin)  

NASA Astrophysics Data System (ADS)

Hydrothermal vents are ephemeral systems. When venting shuts down, sulfide-dependent taxa die off, and non-vent taxa can colonize the hard substrata. In Manus Basin (Papua New Guinea), where active and inactive sulfide mounds are interspersed, hydroids, cladorhizid sponges, barnacles, and bamboo sponges, and other invertebrate types may occupy inactive sulfide mounds. Carbon and nitrogen isotopic compositions of animals occupying inactive sulfide mounds are consistent with nutritional dependence on either chemoautotrophically or photosynthetically produced organic material, but sulfur isotopic compositions of these animals point to a chemoautotrophic source of sulfur from dissolved sulfide in vent fluids rather than sulfur derived from seawater sulfate through photosynthesis. Given that suspension-feeding and micro- carnivorous invertebrates are the biomass dominants at inactive sulfide mounds, the primary source of chemoautotrophic nutrition is likely suspended particulates and organisms delivered from nearby active vents.

van Dover, C. L.; Erickson, K.; Macko, S.

2008-12-01

169

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

170

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

171

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

172

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

173

Effect of ambient oxygen concentration on activities of enzymatic antioxidant defences and aerobic metabolism in the hydrothermal vent worm, Paralvinella grasslei  

Microsoft Academic Search

The alvinellid Paralvinella grasslei is a common endemic polychaete from the deep-sea hydrothermal vent communities located on the East Pacific Rise (EPR). These organisms colonise a large range of microhabitats around active sites where physico-chemical conditions are thought to generate reactive oxygen species (ROS). Furthermore, in this aerobic organism, ROS could also be generated by the activity of the mitochondrial

Benjamin Marie; Bertrand Genard; Jean-Franois Rees; Franck Zal

2006-01-01

174

First Survey For Submarine Hydrothermal Vents In NE Sulawesi, Indonesia  

Microsoft Academic Search

The IASSHA-2001 cruise (Indonesia-Australia Survey for Submarine Hydrothermal Activity) was successfully conducted from June 1 to June 29 on board Baruna Jaya VIII. Preliminary results are reported of the first expedition to locate and study submarine hydrothermal activity in north east Sulawesi. Leg A focussed on Tomini Bay, a virtually unexplored Neogene sedimentary basin. Its objective was to test whether

T. McConachy; R. Binns; H. Permana

2001-01-01

175

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

176

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

177

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

178

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

179

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

180

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

E-print Network

for spreading the hydrothermal chemical and heat flux into the deep-ocean interior and for dispersing propagules activity that alter the global oceanic heat and chemical budgets (1, 2) and support unique chemosynthetic-derived heat and chemicals into the global ocean and transporting propagules between distant vent fields

Paris-Sud XI, Université de

181

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

182

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

183

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

184

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

185

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

186

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

Microsoft Academic Search

The biology of Kickem 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 (?250m depth). Warm water with bubbling gas emanated through rock fissures and sediments. Shrimp

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

2005-01-01

187

Post-capture investigations of hydrothermal vent macro-invertebrates to study adaptations to extreme environments  

Microsoft Academic Search

Typical survival strategies, developed by macro-invertebrates at a variety of reducing marine habitats including deep-sea hydrothermal vents, have been the subject of the laboratory experimentation over the past three decades. This review provides an insight into the international efforts that have converged on the area of laboratory maintenance of such species whose nutritional requirements are outside the usual scope of

Eniko Kadar; Jonathan J. Powell

2006-01-01

188

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

189

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

190

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

NASA Astrophysics Data System (ADS)

We have investigated the N geochemistry of minerals and rocks from contact metamorphic aureoles and hydrothermal vent complexes (HVC) in the Karoo Basin in South Africa. The HVC formed during phreatic eruptions associated with rapid devolatilization and pressure build-up in contact aureoles around early Jurassic sill intrusions. By combining outcrop data from a HVC and core data from contact aureoles, we investigate the relationship between light element release during metamorphism and vertical fluid migration. Sandstone and breccia from the HVC contain early-diagenetic ammonium NH4+-bearing feldspar (buddingtonite) and illite. Ammonium occupies up to 95% of the A site in feldspar, corresponding to concentrations up to 5.2 wt% N. Bulk-rock N isotope data for rocks from inside and outside the hydrothermal vent complex fall into two distinct groups. Background samples have ? 15N air between +1.5 and +4.9, whereas minerals from the vent complex have ? 15N in the range +7.5 to +10.6. The N geochemistry of contact metamorphic shale from the lower stratigraphic units of the Karoo Basin shows that the vitrinite reflectance and ? 15N values are positively correlated. Shale with reflectivity values >4%Ro are enriched in 15N, with ? 15N values between +6 and +14, implying the release of isotopically light N into metamorphic fluids (probably as N 2). We suggest that the relatively high ? 15N values of the early-diagenetic buddingtonite in the HVC reflect exchange of buddingtonite with N-bearing fluids ascending from greater depth after their release during contact metamorphism and dehydration. We present a qualitative model whereby hydrothermal vent complexes represent fluid flow structures after their formation, focusing N-bearing metamorphic fluids sourced in deeper levels of the basin. The release of organic N from sediments at depth in volcanic basins could play a role in the geochemical cycle of N, becoming particularly important during periods of intense volcanic activity.

Svensen, Henrik; Bebout, Gray; Kronz, Andreas; Li, Long; Planke, Sverre; Chevallier, Luc; Jamtveit, Bjrn

2008-10-01

191

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

192

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

193

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

194

Zones of life in the subsurface of hydrothermal vents: A synthesis  

NASA Astrophysics Data System (ADS)

Subsurface microbial communities in Mid-ocean Ridge (MOR) hydrothermal systems host a wide array of unique metabolic strategies, but the spatial distribution of biogeochemical transformations is poorly constrained. Here we present an approach that reexamines chemical measurements from diffuse fluids with models of convective transport to delineate likely reaction zones. Chemical data have been compiled from bare basalt surfaces at a wide array of mid-ocean ridge systems, including 9N, East Pacific Rise, Axial Seamount, Juan de Fuca, and Lucky Strike, Mid-Atlantic Ridge. Co-sampled end-member fluid from Ty (EPR) was used to constrain reaction path models that define diffuse fluid compositions as a function of temperature. The degree of mixing between hot vent fluid (350 deg. C) and seawater (2 deg. C) governs fluid temperature, Fe-oxide mineral precipitation is suppressed, and aqueous redox reactions are prevented from equilibrating, consistent with sluggish kinetics. Quartz and pyrite are predicted to precipitate, consistent with field observations. Most reported samples of diffuse fluids from EPR and Axial Seamount fall along the same predicted mixing line only when pyrite precipitation is suppressed, but Lucky Strike fluids do not follow the same trend. The predicted fluid composition as a function of temperature is then used to calculate the free energy available to autotrophic microorganisms for a variety of catabolic strategies in the subsurface. Finally, the relationships between temperature and free energy is combined with modeled temperature fields (Lowell et al., 2007 Geochem. Geophys., Geosys.) over a 500 m x 500 m region extending downward from the seafloor and outward from the high temperature focused hydrothermal flow to define areas that are energetically most favorable for a given metabolic process as well as below the upper temperature limit for life (~120 deg. C). In this way, we can expand the relevance of geochemical model predictions of bioenergetics by predicting functionally-defined 'Zones of Life' and placing them spatially within the boundary of the 120 deg. C isotherm, estimating the extent of subsurface biosphere beneath mid-ocean ridge hydrothermal systems. Preliminary results indicate that methanogenesis yields the most energy per kg of vent fluid, consistent with the elevated CH4(aq) seen at all three sites, but may be constrained by temperatures too hot for microbial life while available energy from the oxidation of Fe(II) peaks near regions of the crust that are more hospitable.

Larson, B. I.; Houghton, J.; Meile, C. D.

2011-12-01

195

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

196

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

197

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

198

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

199

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

200

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

201

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

202

Morphotypes of virus-like particles in two hydrothermal vent fields on the East Scotia Ridge, Antarctica  

PubMed Central

Viruses from extreme environments are still largely unexplored and may harbor unseen genetic potential. Here, we present a first glance at the morphological diversity of virus like particles (VLPs) from an environment that is extreme in more than one respect: two recently discovered hydrothermal vent fields on the East Scotia Ridge in the Southern Ocean near Antarctica. They are the southernmost hydrothermal sites found to date and have been shown to present a new biogeographic province, containing several new macrofaunal species and associated microbial organisms. Transmission electron microscopy revealed a range of tailed and untailed VLPs of various morphologies as well as an unusual long rod-shaped VLP with three long filaments. Based on its distant similarity with several known archaeal viruses, we hypothesize that this presents a new viral morphology that most likely infects an archaeon. Notably absent in the samples we analyzed were lemon- or spindle-shaped VLPs that have previously been described in other hydrothermal vent settings. PMID:25105058

Millard, Andrew D; Hands-Portman, Ian; Zwirglmaier, Katrin

2014-01-01

203

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

204

Detection of putatively thermophilic anaerobic methanotrophs in diffuse hydrothermal vent fluids.  

PubMed

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 (P(GC)) is significantly higher in the ANME-1GBa group than in other ANME groups. Based on the positive correlation between the P(GC) and optimal growth temperatures (T(opt)) 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

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

2013-02-01

205

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

206

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

207

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

208

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

209

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

210

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

211

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

212

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

213

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

214

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

215

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

216

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

217

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

218

Chemistry of vent fluids and its implications for subsurface conditions at Sea Cliff hydrothermal field, Gorda Ridge  

NASA Astrophysics Data System (ADS)

We report here the first compositional data for fluids from the Sea Cliff hydrothermal field, northern Gorda Ridge, collected in 2000, 2002, and 2004. An unusual aspect of this site is its location 2.6 km east of the axis of spreading, leading to speculation since its discovery in 1988 that this may be an "older" hydrothermal field, as it occurs on crust that the spreading rate would predict to be 100,000 years old. Our results suggest this hydrothermal system is being driven by subsurface magma, as evidenced by (1) elevated 3He/heat ratios, (2) relatively high concentrations of He, and (3) chloride contents less than seawater in the hydrothermal fluids. The measured fluid temperatures were ?308C, but we infer they were >400C at depth. In spite of these elevated temperatures, the fluids exiting from these vents are clear, a consequence of extremely low transition metal concentrations. We attribute the low transition metal contents to loss of these metals below the seafloor, most likely as a result of the slightly elevated pH of the fluids. Neither the fluid compositions nor the setting provides evidence that buried sediments and/or organic matter are responsible for raising the fluid pH. Our favored explanation for the elevated pH is that calcite, deposited as a vein-filling mineral at this site, perhaps when it was closer to the axis and a hydrothermal downflow zone, is currently being dissolved by the hydrothermal fluids. This hypothesis is supported by our geochemical modeling results that suggest the fluids are close to saturation with calcite at in situ conditions. Elevated fluid pH is observed at a number of hydrothermal sites on the global mid-ocean ridge system, and the reason for this has not been well understood. Dissolution of previously deposited calcite may be a heretofore unrecognized mechanism that can explain these observations. Finally, our data suggest the compositions of these fluids are unchanged from 2002 to 2004 and are consistent with water column observations first made at this site in 1985. We therefore interpret the Sea Cliff site to be another hydrothermal area marked by long-term stability in fluid compositions and temperatures.

von Damm, K. L.; Parker, C. M.; Lilley, M. D.; Clague, D. A.; Zierenberg, R. A.; Olson, E. J.; McClain, J. S.

2006-05-01

219

[Comment on Submarine hot springs: Origin of life?] Hydrothermal vents revisited  

NASA Astrophysics Data System (ADS)

It was gratifying to read Peter Bell's synopsis of our paper [Corliss et al., 1981] in the March 23 issue of Eos (Submarine hot springs: Origin of life?) however, in the last sentence, he wrote, They note that microorganisms found in recent expeditions to the submarine hot springs of the East Pacific Rise would be evidence that the processes are still occurring.In our final paragraph we actually said that while events leading to the formation of complex organic compounds and protocell structures may still be occurring in present-day oceanic hydrothermal systems the complex communities of bacteria in modern oceanic environments would outcompete and consume abiotically synthesized protocells Modern-day vent microbiota will probably mask or destroy any evidence for abiotic synthesis in the hydrothermal vents.

Hoffman, Sarah

220

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

221

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

222

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

223

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

224

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

225

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

226

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

227

Adaptations to hypoxia in hydrothermal-vent and cold-seep invertebrates  

Microsoft Academic Search

The deep sea harbors very unusual environments, such as hydrothermal vents and cold seeps, that illustrate an apparent paradox:\\u000a the environmental conditions are very challenging and yet they display a high biomass when compared to the surrounding environment\\u000a at similar depth. Hypoxia is one of the challenges that these species face to live there. Here, we review specific adaptations\\u000a of

Stphane Hourdez; Franois H. Lallier

2007-01-01

228

Adaptations to hypoxia in hydrothermal-vent and cold-seep invertebrates  

Microsoft Academic Search

The deep sea harbors very unusual environments, such as hydrothermal vents and cold seeps, that illustrate an apparent paradox:\\u000a the environmental conditions are very challenging and yet they display a high biomass when compared to the surrounding environment\\u000a at similar depth. Hypoxia is one of the challenges that these species face to live there. Here, we review specific adaptations\\u000a of

Stphane Hourdez; Franois H. Lallier

229

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

230

Post-capture investigations of hydrothermal vent macro-invertebrates to study adaptations to extreme environments  

Microsoft Academic Search

Typical survival strategies, developed by macro-invertebrates at a variety of reducing marine habitats including deep-sea\\u000a hydrothermal vents, have been the subject of the laboratory experimentation over the past three decades. This review provides\\u000a an insight into the international efforts that have converged on the area of laboratory maintenance of such species whose\\u000a nutritional requirements are outside the usual scope of

Eniko Kadar; Jonathan J. Powell

231

Growth increments and stable isotope variation in shells of the deep-sea hydrothermal vent bivalve mollusk Bathymodiolus brevior from the North Fiji Basin, Pacific Ocean  

NASA Astrophysics Data System (ADS)

Bathymodiolus brevior [von Cosel, R., Mtivier, B., Hashimoto, J., 1994. Three new species of Bathymodiolus (Bivalvia: Mytilidae) from hydrothermal vents in the Lau Basin and the North Fiji Basin, western Pacific, and the Snake Pit Area, mid-Atlantic ridge. Veliger 37, 374-392] a bivalve mollusk living at deep-sea hydrothermal vents, exhibits daily microgrowth structures in its shell. This interpretation is substantiated by various lines of evidence: (1) similar shell portions of contemporaneous specimens from the same locality contain almost the same number of microincrements; (2) the number of microincrements coincides with the expected number of days in which shell portions of Bathymodiolus spp. form; (3) the width of such microincrements compares well with daily growth rates estimated for the close relative B. thermophilus [Kenk, V.C., Wilson, B.R., 1985. A new mussel (Bivalvia, Mytilidae) from hydrothermal vents in the Galapagos rift-zone. Malacologia 26, 253-271]; (4) different specimens from the same site show similar microgrowth curves. In addition, we found support for tide-controlled shell growth. Daily shell growth rates fluctuate on a fortnightly basis. Some shell portions also revealed the typical tide-controlled microgrowth pattern commonly observed in intertidal bivalves. Based on the analyses of lunar daily growth increments, a growth curve for B. brevior was computed: X t=14 cm-(14-0.04 cm) e -0.26t. This curve enables estimation of ontogenetic age from shell length. According to this equation, B. brevior reaches its maximum shell length of 14 cm at about age 18. Shell isotope analyses suggest that some major shell growth interruptions or retardations are related to extremely active hydrothermal venting activity. However, shell growth also stopped during periods of low venting implying physiological controls on shell formation. Results of the present study demonstrate that shells of B. brevior provide calendars and environmental data loggers that can complement or partly substitute for long-term observations of venting systems.

Schne, Bernd R.; Giere, Olav

2005-10-01

232

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

E-print Network

microbial diversity at deep-sea vents. Molecular phylogenetic methods are now widely used to assess the microbial diversity in environmental samples [3,4]. Like enrichment culturing, these approaches also haveO-Proteobacterial diversity from a deep-sea hydrothermal vent on the Mid-Atlantic Ridge Erwan Corre

Reysenbach, Anna-Louise

233

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

234

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

235

Biogeography of Persephonella in deep-sea hydrothermal vents of the Western Pacific  

PubMed Central

Deep-sea hydrothermal vent fields are areas on the seafloor with high biological productivity fueled by microbial chemosynthesis. Members of the Aquificales genus Persephonella are obligately chemosynthetic bacteria, and appear to be key players in carbon, sulfur, and nitrogen cycles in high temperature habitats at deep-sea vents. Although this group of bacteria has cosmopolitan distribution in deep-sea hydrothermal ecosystem around the world, little is known about their population structure such as intraspecific genomic diversity, distribution pattern, and phenotypic diversity. We developed the multi-locus sequence analysis (MLSA) scheme for their genomic characterization. Sequence variation was determined in five housekeeping genes and one functional gene of 36 Persephonella hydrogeniphila strains originated from the Okinawa Trough and the South Mariana Trough (SNT). Although the strains share >98.7% similarities in 16S rRNA gene sequences, MLSA revealed 35 different sequence types (ST), indicating their extensive genomic diversity. A phylogenetic tree inferred from all concatenated gene sequences revealed the clustering of isolates according to the geographic origin. In addition, the phenotypic clustering pattern inferred from whole-cell matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF/MS) analysis can be correlated to their MLSA clustering pattern. This study represents the first MLSA combined with phenotypic analysis indicative of allopatric speciation of deep-sea hydrothermal vent bacteria. PMID:23630523

Mino, Sayaka; Makita, Hiroko; Toki, Tomohiro; Miyazaki, Junichi; Kato, Shingo; Watanabe, Hiromi; Imachi, Hiroyuki; Watsuji, Tomo-o; Nunoura, Takuro; Kojima, Shigeaki; Sawabe, Tomoo; Takai, Ken; Nakagawa, Satoshi

2013-01-01

236

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

237

Extremely Thermophilic Fermentative Archaebacteria of the Genus Desulfurococcus from Deep-Sea Hydrothermal Vents  

PubMed Central

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 95C); and their archaebacterial characteristics: absence of murein, presence of certain diand tetraethers, and response to specific antibiotics. The two strains (S and SY, respectively) differed slightly in their optimum growth temperatures (85 and 90C, 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 90C were about 40% lower than those at 1 atm (101.29 kPa), and no growth occurred at 100 and 110C, 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. Images PMID:16347631

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

1988-01-01

238

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

239

Scavenging rates of dissolved manganese in a hydrothermal vent plume  

NASA Astrophysics Data System (ADS)

The biogeochemical scavenging of dissolved manganese (Mn) from hydrothermal plumes was investigated using radiotracer ( 54Mn) techniques. The measured scavenging rate constant, k 1, was lowest in the buoyant plume (<0.2 y -1), increasing to 2 y -1 in the non-buoyant plume at distances of 20 km from the ridge valley axis. The direct biological contribution to the dissolved Mn scavenging rate (i.e the fraction suppressed by the addition of a metabolic poison) also increased over the same distances, being minor or absent at plume depths in the proximal plume, yet the major component at distal plume stations. These and other data suggest that the capacity for scavenging dissolved Mn onto particles evolves with increasing age of the plume, suggestive of a microbial response to changing conditions within the plume. Estimated maximum scavenging rates of dissolved Mn onto particles ( RDMn = k 1 [DMn])were noted at plume depths for all stations, a function of very high dissolved Mn concentrations in the case of the buoyant plume and proximal non-buoyant plume. RDMn values, integrated over plume depths, ranged from 3.4 to 1.7 mM m -2 y -1 for the non-buoyant plume at on-axis and off-axis stations, respectively. The application of the data to the dispersal of hydrothermal constituents and to plume aging is discussed.

Cowen, James P.; Massoth, Gary J.; Feely, Richard A.

1990-10-01

240

Conjugating effects of symbionts and environmental factors on gene expression in deep-sea hydrothermal vent mussels  

PubMed Central

Background The deep-sea hydrothermal vent mussel Bathymodiolus azoricus harbors thiotrophic and methanotrophic symbiotic bacteria in its gills. While the symbiotic relationship between this hydrothermal mussel and these chemoautotrophic bacteria has been described, the molecular processes involved in the cross-talking between symbionts and host, in the maintenance of the symbiois, in the influence of environmental parameters on gene expression, and in transcriptome variation across individuals remain poorly understood. In an attempt to understand how, and to what extent, this double symbiosis affects host gene expression, we used a transcriptomic approach to identify genes potentially regulated by symbiont characteristics, environmental conditions or both. This study was done on mussels from two contrasting populations. Results Subtractive libraries allowed the identification of about 1000 genes putatively regulated by symbiosis and/or environmental factors. Microarray analysis showed that 120 genes (3.5% of all genes) were differentially expressed between the Menez Gwen (MG) and Rainbow (Rb) vent fields. The total number of regulated genes in mussels harboring a high versus a low symbiont content did not differ significantly. With regard to the impact of symbiont content, only 1% of all genes were regulated by thiotrophic (SOX) and methanotrophic (MOX) bacteria content in MG mussels whereas 5.6% were regulated in mussels collected at Rb. MOX symbionts also impacted a higher proportion of genes than SOX in both vent fields. When host transcriptome expression was analyzed with respect to symbiont gene expression, it was related to symbiont quantity in each field. Conclusions Our study has produced a preliminary description of a transcriptomic response in a hydrothermal vent mussel host of both thiotrophic and methanotrophic symbiotic bacteria. This model can help to identify genes involved in the maintenance of symbiosis or regulated by environmental parameters. Our results provide evidence of symbiont effect on transcriptome regulation, with differences related to type of symbiont, even though the relative percentage of genes involved remains limited. Differences observed between the vent site indicate that environment strongly influences transcriptome regulation and impacts both activity and relative abundance of each symbiont. Among all these genes, those participating in recognition, the immune system, oxidative stress, and energy metabolism constitute new promising targets for extended studies on symbiosis and the effect of environmental parameters on the symbiotic relationships in B. azoricus. PMID:22034982

2011-01-01

241

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

242

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

243

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

244

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

245

The concentration function of the bottom fauna at the deep sea hydrothermal vent fields  

NASA Astrophysics Data System (ADS)

Specific features of the concentration of a group of chemical elements in the dominant bottom organisms are analyzed. The studied organisms inhabit geochemically different hydrothermal fields: Menez-Gwen, Broken-Spur, and Rainbow on the Mid Atlantic Ridge (MAR), as well as 950'N and Guyamas on the East Pacific Rise (EPR). It was revealed for the first time that bottom organisms accumulate 102 to 105 times less the macro-ions of marine water Na and K from the water of biotopes than heavy metals. The intensive concentration of chemical elements, especially of heavy metals, and the high biomasses of bottom organisms associated with hydrothermal vents suggest that this fauna serves as a powerful deepwater biofilter. The absence of pronounced differences between values of coefficients of accumulation for the same metals in the benthos of various MAR and EPR fields evidences the uniformity of the concentration function of the hydrothermal fauna.

Demina, L. L.

2010-01-01

246

Structural and functional diversity of microbial communities beneath the hydrothermal vent at the Iheya North field of the Mid-Okinawa Trough (IODP Expedition 331)  

NASA Astrophysics Data System (ADS)

Complex and diverse microbial communities in deep-sea hydrothermal fluids are apparently different from those in ambient seawater, some of which are predicted to migrate along hydrothermal vein from "subvent biosphere". Subseafloor environment just beneath active hydrothermal vent has been expected to be one of the most conceivable habitats for metabolically active and diverse microbial community. We conducted the scientific ocean drilling (IODP Expedition 331) for the Iheya North hydrothermal field in the Mid-Okinawa Trough in Sept. 2010, and collected core samples from the subseafloor biosphere beneath the hydrothermal vent. IODP Site C0014 was located 450 m east off the main hydrothermal vent. Temperature exceeded the limit of life at the depth of approximately 40 m below the seafloor. Both microscopy and quantitative PCR analyses successfully detected microbial populations in the shallower zone above 15 mbsf. However, the cultivation attempts of (hyper-)thermophiles were unsuccessful all over the depth. Culture-independent molecular biological experiments showed that microbial community composition distinctly changed with depth, possibly because of physicochemical conditions such as methane, sulfate and temperature. Microbial activities of methanogenesis and anaerobic methane oxidation were in accordance with the geochemical profiles of methane and sulfate. These results indicated the presence of functionally active subseafloor microbial communities but those were different from expected members in subvent biosphere. Site C0017 located 1.6 km east off the hydrothermal vent is a potential seawater recharge zone of the hydrothermal system, where seawater penetrates into the oceanic crust. The lithostratigraphy consists of characteristic coarse angular pumiceous gravel, lying above and below hemipelagic mud, in which high permeability may allow entrainment of seawater. As is the case with sedimentary subsurface environments, uncultivated archaeal groups were dominantly detected in the hemipelagic sediment above and below pumice layer. In contrast, the ammonia-oxidizing archaea (Nitrosopumilales) were outstandingly dominant at pumice layer of around 20 mbsf, possibly related to oxidative seawater transport. At the deeper layer of around 150 mbsf, where high temperature over 90C was recorded, microbial community structure was similar to that in high temperature zone of Site C0014. Our data suggest that the temperature gradient formed by hydrothermal activity is one of the important factors controlling changes in subseafloor microbial communities.

Yanagawa, K.; Nunoura, T.; Kawagucci, S.; Hirai, M.; Sunamura, M.; Breuker, A.; Brandt, L.; House, C. H.; McAllister, S. M.; Moyer, C. L.; Takai, K.

2012-12-01

247

High-Resolution Magnetic Field and Bathymetric Imaging of Hydrothermal Vent Areas using Autonomous Underwater Vehicles, Remotely Operated Vehicles and Submersibles  

NASA Astrophysics Data System (ADS)

High-resolution, near-bottom bathymetric and magnetic field surveys have been carried out over hydrothermal vent areas using the autonomous underwater vehicle ABE, the ROV Jason and ALVIN. Bathymetry is measured using a 675 kHz, scanning pencil-beam altimeter and, most recently, a 200 kHz swath mapping sonar. Vehicle depth is obtained by pressure sensor and vector magnetic field is measured using either a 3-axis fluxgate or, most recently, a digital magneto-resistor sensor. Typical survey altitude ranges from 20 m (Jason, ALVIN) to 40-60 m (ABE), with line spacing ranging from 20 to 40-60 m respectively. This survey geometry provides sufficient resolution for the detection of magnetic anomalies associated with geological features, most notably hydrothermal vents. We present detailed surveys over 5 hydrothermal sites found at mid-ocean ridges that range from fast to slow spreading. The TAG hydrothermal area, on the slow spreading Mid-Atlantic Ridge, was imaged using ALVIN in 1993 and has a magnetic low directly beneath the active chimney complex. On the intermediate-rate Endeavour segment of the Juan de Fuca Ridge (JDF), we imaged individual chimneys of Main Endeavour Field (MEF) and found that they are associated with discrete magnetic lows. On Explorer Ridge, ABE mapping in 2002 revealed that the Magic Mountain hydrothermal area is also associated with a region of low magnetization. In 2002, at the intermediate-rate Galapagos Rift at 86W, ABE mapped the original "Rose Garden" hydrothermal area, which has now become inactive. This site has a magnetic low associated with it while only 200 m NW of this site, an area of recent low-T hydrothermal activity (i.e. Rosebud site) does not produce a magnetic response. A 2001 ABE bathymetric and magnetic survey at the EPR crest at 9 50N shows weak magnetic anomaly lows associated with active high-T venting in the axial trough. The observed magnetic anomalies share a number of common features, most notably a circular plan view geometry (typical diameter 100m) that indicates a discrete and highly localized anomalous magnetization source (i.e. an up-flow pipe geometry). Magnetic lows are found at both active and inactive (or relict) vent sites indicating that crustal alteration of the extrusive basalt rather than thermal demagnetization is the likely cause for low magnetization. Near-bottom magnetic and bathymetric surveys can be successful in locating zones of active and inactive hydrothermal activity.

Tivey, M.

2003-04-01

248

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

249

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

250

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

251

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

252

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

253

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

254

Evidence for hydrothermal venting in Fe isotope compositions of the deep Pacific Ocean through time  

NASA Astrophysics Data System (ADS)

Temporal variations in Fe isotope compositions at three locations in the Pacific Ocean over the last 10 Ma are inferred from high-resolution analyses of three hydrogenetic ferromanganese crusts. Iron pathways to the central deep Pacific Ocean appear to have remained constant over the past 10 Ma, reflected by a remarkably constant Fe isotope composition, despite large changes in the Fe delivery rates to the surface ocean via dust. These results suggest that the Fe cycle in the deep ocean is decoupled from that in surface waters. By contrast, one ferromanganese crust from the Izu-Bonin (IB) back-arc/marginal basin of the W. Pacific exhibits large ? 56Fe variations. In that crust, decreases in ? 56Fe values correlate with increases in Mn, Mg, Ni, Cu, Zn, Mo, and V contents, and consistent with periods of intense hydrothermal input and increased growth rates. A second crust located within 100 km of the first IB sample does not record any of these periods of enhanced hydrothermal input. This probably reflects the isolated pathways by which hydrothermally sourced Fe may have migrated in the back arc, highlighting the high degree of provinciality that Fe isotopes may have in the modern (oxic) oceans. Our results demonstrate that despite efficient removal at the source, hydrothermal Fe injected into the deep ocean could account for a significant fraction of the dissolved Fe pool in the deep ocean, and that hydrothermally sourced Fe fluxes to the open ocean may have lower ? 56Fe values than those measured so far in situ at hydrothermal vents. Correlation between ? 56Fe values and elements enriched in hydrothermal fluids may provide a means for distinguishing hydrothermal Fe from other low-? 56Fe sources to the oceans such as dissolved riverine Fe or porewaters in continental shelf sediments.

Chu, N.-C.; Johnson, C. M.; Beard, B. L.; German, C. R.; Nesbitt, R. W.; Frank, M.; Bohn, Marcel; Kubik, P. W.; Usui, A.; Graham, I.

2006-05-01

255

DNA-DNA Solution Hybridization Studies of the Bacterial Symbionts of Hydrothermal Vent Tube Worms (Riftia pachyptila and Tevnia jerichonana)  

PubMed Central

The giant tube worm, Riftia pachyptila (phylum Vestimentifera), is known only from four widely separated sulfide-rich deep-sea hydrothermal vent systems. This invertebrate is nourished by intracellular, chemoautotrophic bacterial symbionts which reside in a specialized trophosome tissue. The symbiont has not been cultured independently and is believed to be acquired de novo by host larvae of each generation. In the current study, R. pachyptila symbiont DNA was purified from the two most distant sites on the basis of its difference in density versus host DNA. These two standards were hybridized against trophosome DNAs of 13 individuals from the Guaymas Basin, Galapagos Rift, and 13N vents. This indicated that all R. pachyptila symbionts are conspecific and that the variability in DNA-DNA hybridization (relative binding ratio [RBR]) was comparable within or between widely separated vents. The symbiont of another tube worm, Tevnia jerichonana, was found to be the same as that of R. pachyptila, the first case in which distinct hosts possess the same sulfur bacterial symbiont. By contrast, Lamellibrachia sp. (same class as T. jerichonana) showed insignificant RBR with the R. pachyptila symbiont. DNA derived from solely eucaryotic tissue of R. pachyptila showed a surprisingly high RBR (20 to 50) with density-separated DNA standards. With DNAs obtained from physically separated symbionts, independent solution hybridization experiments confirmed the above-described conclusions. Possible explanations for this host-symbiont homology are discussed. PMID:16348457

Edwards, Deeanne B.; Nelson, Douglas C.

1991-01-01

256

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

257

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

258

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

259

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.

260

Genetic diversity of hydrothermal-vent barnacles in Manus Basin  

NASA Astrophysics Data System (ADS)

We evaluated mitochondrial cytochrome oxidase I genetic diversity of two barnacle species (Eochionelasmus ohtai manusensis, Vulcanolepas cf. parensis) at three sites in Manus Basin (Solwara 1, South Su, Solwara 8). There was no evidence for within-site or between-site genetic differentiation for either species. While E. ohtai manusensis showed limited genetic variation, V. cf. parensis showed greater variation, with sequences distributed between two divergent groups. Assuming the cytochrome oxidase I gene is not under selection, significantly negative Tajima's D in E. ohtai manusensis is consistent with a recent population expansion due to a bottleneck or founder effect, whereas V. cf. parensis (combined groups) did not depart from a stable effective population size. Considering the groups separately, V. cf. parensis Group 1 (but not Group 2) showed a negative Tajima's D, indicating these groups may have encountered different historical demographic conditions. Data reported here are part of a baseline study against which recovery of genetic diversity following mineral extraction at Solwara 1 can be measured.

Plouviez, Sophie; Schultz, Thomas F.; McGinnis, Gwendolyn; Minshall, Halle; Rudder, Meghan; Van Dover, Cindy L.

2013-12-01

261

Lysogenic virus-host interactions predominate at deep-sea diffuse-flow hydrothermal vents.  

PubMed

The consequences of viral infection within microbial communities are dependent on the nature of the viral life cycle. Among the possible outcomes is the substantial influence of temperate viruses on the phenotypes of lysogenic prokaryotes through various forms of genetic exchange. To date, no marine microbial ecosystem has consistently shown a predisposition for containing significant numbers of inducible temperate viruses. Here, we show that deep-sea diffuse-flow hydrothermal vent waters display a consistently high incidence of lysogenic hosts and harbor substantial populations of temperate viruses. Genetic fingerprinting and initial metagenomic analyses indicate that temperate viruses in vent waters appear to be a less diverse subset of the larger virioplankton community and that these viral populations contain an extraordinarily high frequency of novel genes. Thus, it appears likely that temperate viruses are key players in the ecology of prokaryotes within the extreme geothermal ecosystems of the deep sea. PMID:18719614

Williamson, Shannon J; Cary, S Craig; Williamson, Kurt E; Helton, Rebekah R; Bench, Shellie R; Winget, Danielle; Wommack, K Eric

2008-11-01

262

Bacterial sulfur cycling shapes microbial communities in surface sediments of an ultramafic hydrothermal vent field.  

PubMed

The ultramafic-hosted Logatchev hydrothermal field (LHF) is characterized by vent fluids, which are enriched in dissolved hydrogen and methane compared with fluids from basalt-hosted systems. Thick sediment layers in LHF are partly covered by characteristic white mats. In this study, these sediments were investigated in order to determine biogeochemical processes and key organisms relevant for primary production. Temperature profiling at two mat-covered sites showed a conductive heating of the sediments. Elemental sulfur was detected in the overlying mat and metal-sulfides in the upper sediment layer. Microprofiles revealed an intensive hydrogen sulfide flux from deeper sediment layers. Fluorescence in situ hybridization showed that filamentous and vibrioid, Arcobacter-related Epsilonproteobacteria dominated the overlying mats. This is in contrast to sulfidic sediments in basalt-hosted fields where mats of similar appearance are composed of large sulfur-oxidizing Gammaproteobacteria. Epsilonproteobacteria (7-21%) and Deltaproteobacteria (20-21%) were highly abundant in the surface sediment layer. The physiology of the closest cultivated relatives, revealed by comparative 16S rRNA sequence analysis, was characterized by the capability to metabolize sulfur components. High sulfate reduction rates as well as sulfide depleted in (34)S further confirmed the importance of the biogeochemical sulfur cycle. In contrast, methane was found to be of minor relevance for microbial life in mat-covered surface sediments. Our data indicate that in conductively heated surface sediments microbial sulfur cycling is the driving force for bacterial biomass production although ultramafic-hosted systems are characterized by fluids with high levels of dissolved methane and hydrogen. PMID:21895907

Schauer, Regina; Ry, Hans; Augustin, Nico; Gennerich, Hans-Hermann; Peters, Marc; Wenzhoefer, Frank; Amann, Rudolf; Meyerdierks, Anke

2011-10-01

263

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

264

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

265

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

266

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

267

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

268

Unusual geochemistry of hydrothermal vents on submarine arc volcanoes: Kasuga Seamounts, Northern Mariana Arc  

NASA Astrophysics Data System (ADS)

DSRV Alvin dives in the Northern Mariana island arc recovered warm hydrothermal fluids from the summit areas of seamounts Kasuga 2 and Kasuga 3, as well as hydrothermal deposits of elemental sulfur, Fe- and Mn-oxides, and nontronite. The composition of a gas-rich 39C vent fluid sampled from Kasuga 2 Seamount is unusual compared to other submarine hydrothermal fluids in that it is enriched by 27% in Mg 2+ and 17% in SO 42-, and depleted by 64% in Ca 2+, relative to ambient seawater. The elevated concentrations of dissolved CO 2 (calculated from pH and AT), HCO 3- and SO 42+, and near absence of H 2S, suggest that the unusual composition of this sample may result from the sub-seafloor addition of volcanic CO 2 and SO 2 to a seawater-derived hydrothermal fluid, resulting in: (1) 'chemical weathering' reactions, whereby igneous minerals or alteration phases are attacked by CO 2, adding Mg 2+ and other cations, Si, and HCO 3- into solution; and (2) hydrolysis of SO 2 to SO 42- and S(0), adding excess SO 42- with a light ? 34S signature to the fluid and causing deposition of elemental sulfur at the seafloor vents. Saturation-state calculations suggest that the concentrations of Si and Ca 2+ in the fluid may be controlled at saturation with amorphous silica and dolomite respectively. The origin of the 9.3C fluid collected from Kasuga 3 is difficult to determine because it is compositionally close to ambient seawater and shows possible evidence of both high- and low-temperature seawater-rock reaction. Banded and interlayered deposits of nontronite and Fe- and Mn-oxides were recovered from the Kasuga 3 summit, with oxygen-isotope geothermometry suggesting a formation temperature of 22C for the nontronite.

McMurtry, G. M.; Sedwick, P. N.; Fryer, P.; VonderHaar, D. L.; Yeh, H.-W.

1993-02-01

269

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

270

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

271

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

272

Measurements and Models of Heat Flux Magnitude and Variance from the Main Endeavour Hydrothermal Vent Field  

NASA Astrophysics Data System (ADS)

Precise measurement of the total heat flux from the Main Endeavour hydrothermal vent field (MEF) to the Northeast Pacific Ocean is confounded by tidal and topographically-controlled currents within the axial valley of the Endeavour segment. The magnitude of the total heat flux is dominated by vertical flux through a horizontal plane 75m above the vent field, observed to be 590+/-51MW. The variance of the vertical flux, based on 12 surveys of velocity and hydrography over the MEF made by the Autonomous Benthic Explorer (ABE), compares well with the variance expected at the survey elevation from a model of axisymmetric hydrothermal plumes. In contrast to the vertical flux, the horizontal flux of heat, advected laterally by currents through the MEF perimeter (<75m above the bottom), has a low observed mean magnitude of order 10MW. The horizontal flux, estimated by interpreting CTD and current data in multiple ways, has a high variance which is explained by an advection/diffusion, or ``puff,'' model initialized with current meter data acquired near the MEF. >http://www2.ocean.washington.edu/ ~scottv/research/2001agu/

Veirs, S. R.; Stahr, F. R.; McDuff, R. E.; Thomson, R. E.; Yoerger, D. R.; Bradley, A. M.

2001-12-01

273

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

PubMed Central

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 103- and 104-fold dilutions of the continental slope sediment, oxidized thiosulfate to sulfate and fell into a distinct phylogenetic cluster of marine alpha-Proteobacteria. Phylogenetically and physiologically, these sediment strains resembled the sulfate-producing thiosulfate oxidizers from the Galapagos hydrothermal vents while showing habitat-related differences in growth temperature, rate and extent of thiosulfate utilization, and carbon substrate patterns. The abyssal deep-sea sediments yielded predominantly base-producing thiosulfate-oxidizing isolates related to Antarctic marine Psychroflexus species and other cold-water marine strains of the Cytophaga-Flavobacterium-Bacteroides phylum, in addition to gamma-proteobacterial isolates of the genera Pseudoalteromonas and Halomonas-Deleya. Bacterial thiosulfate oxidation is found in a wide phylogenetic spectrum of Flavobacteria and Proteobacteria. PMID:10919760

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

2000-01-01

274

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

275

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

276

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

277

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

278

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

279

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

280

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

281

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

282

*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

283

A modeling approach of the influence of local hydrodynamic conditions on larval dispersal at hydrothermal vents.  

PubMed

Deep-sea hydrothermal vent animal communities along oceanic ridges are both patchy and transient. Larval dispersal is a key factor in understanding how these communities function and are maintained over generations. To date, numerical approaches simulating larval dispersal considered the effect of oceanic currents on larval transportation over hundreds of kilometers but very seldom looked at the effect of local conditions within meters around chimneys. However, small scale significant variations in the hydrodynamics may influence larval fate in its early stages after release, and hence have a knock-on effect on both dispersal and colonization processes. Here we present a new numerical approach to the study of larval dispersal, considering small scales within the range of the biological communities, called "bio-hydrodynamical" scale, and ranging from a few centimeters to a few meters around hydrothermal sources. We use a physical model for the vent based on jet theory and compute the turbulent velocity field around the smoker. Larvae are considered as passive particles whose trajectories are affected by hydrodynamics, topography of the vent chimney and larval biological properties. Our model predicts that bottom currents often dominate all other factors either by entraining all larvae away from the vent or enforcing strong colonization rates. When bottom currents are very slow (<1 mms(-1)), general larvae motion is upwards due to entrainment by the main smoker jet. In this context, smokers with vertical slopes favor retention of larvae because larval initial trajectory is nearly parallel to the smoker wall, which increases the chances to settle. This retention phenomenon is intensified with increasing velocity of the main smoker jet because entrainment in the high velocity plume is preceded by a phase when larvae are attracted towards the smoker wall, which occurs earlier with higher velocity of the main jet. Finally, the buoyancy rate of the larvae, measured to be in the range of 0.01 mms(-1), is generally irrelevant unless hydrodynamic conditions are balanced, i.e. if the buoyancy rate is comparable to both the bottom current speed and the local water velocity due to entrainment by close smokers. Overall, our model evidences the strong effect of the release point of larvae on their future entrainment within local fluxes. Larvae released from smoker walls might have an entirely different fate than those released further away in the water column. The latter are not, or less, affected by near-chimney hydrodynamics. PMID:18834891

Bailly-Bechet, Marc; Kerszberg, Michel; Gaill, Franoise; Pradillon, Florence

2008-12-01

284

Carbon dioxide use by chemoautotrophic endosymbionts of hydrothermal vent vestimentiferans: affinities for carbon dioxide, absence of carboxysomes, and ?13C values  

Microsoft Academic Search

The hydrothermal vent vestimentiferans Riftia pachyptila Jones, 1981 and Ridgeia piscesae Jones, 1985 live in habitats with different abundances of external CO2. R. pachyptila is found in areas with a high input of hydrothermal fluid, and therefore with a high [CO2]. R. piscesae is found in a range of habitats with low to high levels of hydrothermal fluid input, with

K. M. Scott; M. Bright; S. A. Macko; C. R. Fisher

1999-01-01

285

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

286

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

287

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

288

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

289

In-Situ pH Measurements in Mid-Ocean Ridge Hydrothermal Vent Fluids: Constraints on Subseafloor Alteration Processes at Crustal Depths  

NASA Astrophysics Data System (ADS)

Developments in electrochemistry and material science have facilitated the construction of ceramic (YSZ) based chemical sensor systems that can be used to measure and monitor pH and redox in aqueous fluids at elevated temperatures and pressures. In recent years, these sensor systems have been deployed to acquire real-time and time series in-situ data for high-temperature hydrothermal vent fluids at the Main Endeavour Field (Juan de Fuca Ridge), 9oN (East Pacific Rise), and at the ultramafic-hosted Rainbow field (36oN, Mid-Atlantic Ridge). Here we review in-situ pH data measured at these sites and apply these data to estimate the pH of fluids ascending to the seafloor from hydrothermal alteration zones deeper in the crust. In general, in-situ pH measured at virtually all vent sites is well in excess of that measured shipboard owing to the effects of temperature on the distribution of aqueous species and the solubility of metal sulfides, especially Cu and Zn, originally dissolved in the vent fluids. In situ pH measurements determined at MEF (Sully vent) and EPR 9oN (P-vent) in 2005 and 2008 were 4.4 0.02 and 5.050.05, respectively. The temperature and pressure (seafloor) of the vent fluids at each of the respective sites were 356oC and 220 bar, and 380oC and 250 bar. Plotting these data with respect to fluid density reveals that the in-situ pH of each vent fluid is approximately 1.5 pH units below neutrality. The density-pH (in-situ) correlation, however, is important because it provides a means from which the vent fluids were derived. Using dissolved silica and chloride from fluid samples at the MEF (Sully) suggest T/P conditions of approximately 435oC, 380 bar, based on quartz-fluid and NaCl-H2O systems. At the fluid density calculated for these conditions, pH (in-situ) is predicted to be ~6.2. Attempts are presently underway to assess the effect of the calculated pH on metal sulfide and silicate (e.g., plagioclase, chlorite) solubility in comparison with constraints imposed by the full range of chemical components in the vent fluids sampled and analyzed in association with pH (in-situ) measurements. Since pH is a master variable in all geochemical systems, the novel approach proposed here may provide new insight on hydrothermal alteration processes at conditions difficult or impossible to assess by more traditional means, ultimately influencing hydrothermal fluid fluxes.

Schaen, A. T.; Ding, K.; Seyfried, W. E.

2013-12-01

290

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

291

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

292

Novel Forms of Structural Integration between Microbes and a Hydrothermal Vent Gastropod from the Indian Ocean  

PubMed Central

Here we describe novel forms of structural integration between endo- and episymbiotic microbes and an unusual new species of snail from hydrothermal vents in the Indian Ocean. The snail houses a dense population of ?-proteobacteria within the cells of its greatly enlarged esophageal gland. This tissue setting differs from that of all other vent mollusks, which harbor sulfur-oxidizing endosymbionts in their gills. The significantly reduced digestive tract, the isotopic signatures of the snail tissues, and the presence of internal bacteria suggest a dependence on chemoautotrophy for nutrition. Most notably, this snail is unique in having a dense coat of mineralized scales covering the sides of its foot, a feature seen in no other living metazoan. The scales are coated with iron sulfides (pyrite and greigite) and heavily colonized by ?- and ?-proteobacteria, likely participating in mineralization of the sclerites. This novel metazoan-microbial collaboration illustrates the great potential of organismal adaptation in chemically and physically challenging deep-sea environments. PMID:15128570

Goffredi, Shana K.; Warn, Anders; Orphan, Victoria J.; Van Dover, Cindy L.; Vrijenhoek, Robert C.

2004-01-01

293

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

294

Mineralogical gradients associated with alvinellids at deep-sea hydrothermal vents  

NASA Astrophysics Data System (ADS)

Alvinella pompejana and Alvinella caudata live in organic tubes on active sulphide chimney walls at deep-sea hydrothermal vents. These polychaete annelids are exposed to extreme thermal and chemical gradients and to intense mineral precipitation. This work points out that mineral particles associated with Pompeii worm ( A. pompejana and A. caudata) tubes constitute useful markers for evaluating the chemical characteristics of their micro-environment. The minerals associated with these worm tubes were analysed on samples recovered from an experimental alvinellid colony, at different locations in the vent fluid-seawater interface. Inhabited tubes from the most upper and lower parts of the colony were analysed by light and electron microscopies, X-ray microanalysis and X-ray diffraction. A change was observed from a Fe-Zn-S mineral assemblage to a Zn-S assemblage at the millimeter scale from the outer to the inner face of a tube. A similar gradient in proportions of minerals was observed at a decimeter scale from the lower to the upper part of the colony. The marcasite/pyrite ratio of iron disulphides also displays a steep decrease along the few millimeters adjacent to the external tube surface. The occurrence of these gradients indicates that the micro-environment within the tube differs from that outside the tube, and suggests that the tube wall acts as an efficient barrier to the external environment.

Zbinden, Magali; Le Bris, Nadine; Compre, Philippe; Martinez, Isabelle; Guyot, Franois; Gaill, Franoise

2003-02-01

295

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

296

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

PubMed

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 host-symbiont combinations are predictably distributed across a regional geochemical gradient. Metatranscriptomes of these symbionts reveal key differences in energy and nitrogen metabolism relating to both environmental chemistry (that is, the relative expression of genes) and symbiont phylogeny (that is, the specific pathways employed). Unexpectedly, dramatic differences in expression of transposases and flagellar genes suggest that different symbiont types may also have distinct life histories. These data further our understanding of these symbionts' metabolic capabilities and their expression in situ, and suggest an important role for symbionts in mediating their hosts' interaction with regional-scale differences in geochemistry. PMID:23619306

Sanders, J G; Beinart, R A; Stewart, F J; Delong, E F; Girguis, P R

2013-08-01

297

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

298

Photoprotective bioactivity present in a unique marine bacteria collection from Portuguese deep sea hydrothermal vents.  

PubMed

Interesting biological activities have been found for numerous marine compounds. In fact, screening of phylogenetically diverse marine microorganisms from extreme environments revealed to be a rational approach for the discovery of novel molecules with relevant bioactivities for industries such as pharmaceutical and cosmeceutical. Nevertheless, marine sources deliverables are still far from the expectations and new extreme sources of microbes should be explored. In this work, a marine prokaryotic collection from four Mid-Atlantic Ridge (MAR) deep sea hydrothermal vents near the Azores Islands, Portugal, was created, characterized and tested for its photoprotective capacity. Within 246 isolates, a polyphasic approach, using chemotaxonomic and molecular typing methods, identified 23-related clusters of phenetically similar isolates with high indexes of diversity. Interestingly, 16S rRNA gene sequencing suggested the presence of 43% new prokaryotic species. A sub-set of 139 isolates of the prokaryotic collection was selected for biotechnological exploitation with 484 bacterial extracts prepared in a sustainable upscalling manner. 22% of the extracts showed an industrially relevant photoprotective activity, with two extracts, belonging to new strains of the species Shewanella algae and Vibrio fluvialis, uniquely showing UV-A, UV-B and UV-C protective capacity. This clearly demonstrates the high potential of the bacteria MAR vents collection in natural product synthesis with market applications. PMID:23665957

Martins, Ana; Tenreiro, Tania; Andrade, Gonalo; Gadanho, Mrio; Chaves, Sandra; Abrantes, Marta; Calado, Patrcia; Tenreiro, Rogrio; Vieira, Helena

2013-05-01

299

Metal Sulfide and Pyrite Nanoparticles form in Hydrothermal Vent Waters (Invited)  

NASA Astrophysics Data System (ADS)

Using separate analytical schemes on 200 nm filtered solutions followed by induced precipitation of nanoparticles, we discriminated the sulfide and metal composition in metal sulfide nanoparticles. Both acid volatile sulfide (AVS) and chromium reducible sulfide (CRS) as well as hydrochloric acid (analogous to AVS) and nitric acid (analogous to CRS) metal extractions provide evidence that less than 200 nm pyrite particles form in high temperature hydrothermal chimney fluids. In some vents, nanoparticulate pyrite constitutes up to 10% of the total vent-emitted iron. In Lau Basin, this nanoparticulate pyrite may be highly substituted with other metals, including zinc and copper, which can form their own nanoparticulate metal sulfides. These findings have potential implications for the overall ocean budget of metals and sulfur, as metal sulfide nanoparticles are resistant to the rapid precipitation that occurs with larger particles. Also, metal sulfide nanoparticles of Zn, Ag, and Cd exhibit oxidation half lives with dissolved oxygen ranging from one month to one year at 25oC, and these half lives would be four times slower at the ocean bottom temperature of 2oC. Similar slow reactivity is likely for nanoparticulate pyrite but has not been documented yet. Nanoparticulate pyrite is a mechanism by which Fe can avoid rapid Fe(II) oxidation (on the scale of hours) followed by Fe(III) precipitation and/or complexation as well as the rapid precipitation that affects larger micrometer sized pyrite particles. Slow pyrite oxidation would increase the probability of vent-derived Fe to be transported long distances in the deep ocean.

Luther, G. W.; Yucel, M.; Gartman, A.

2010-12-01

300

Hydrothermal vents near a mantle hot spot: the Lucky Strike vent field at 37N on the Mid-Atlantic Ridge  

Microsoft Academic Search

The Lucky Strike hydrothermal field occurs in the summit basin of a large seamount that forms the shallow center of a 65 km long ridge segment near 37N on the Mid-Atlantic Ridge. The depth and chemistry of the ridge segment are influenced by the Azores hot spot, and this hydrothermal field is the first Atlantic site found on crust that

C. Langmuir; S. Humphris; D. Fornari; C. Van Dover; K. Von Damm; M. K. Tivey; D. Colodner; J.-L. Charlou; D. Desonie; C. Wilson; Y. Fouquet; G. Klinkhammer; H. Bougault

1997-01-01

301

Microhabitat variation in the hydrothermal vent mussel, Bathymodiolus thermophilus, at the Rose Garden vent on the Galapagos Rift  

NASA Astrophysics Data System (ADS)

Clumps of Bathymodiolus thermophilus were collected from three discrete areas at the 'Rose Garden' site on the Galapagos Rift using the deep submersible Alvin. Two mussel collections were made from the central Riftia mass, an area associated with very active venting, and three other collections were of two different peripheral mussel clumps. Before collection the clumps were extensively photographed and the water at two of the 'microhabitats' was analysed in situ for oxygen silica, sulfide and temperature. Sulfide levels of up to 300 ?M were recorded at the central collection site, while the highest sulfide level recorded at the peripheral site assayed was 35 ?M. Levels of RuBP carboxylase activity in the gills were significantly higher in mussels collected from the central ' Riftia site' than in either peripheral site. ATP sulfurylase was significantly higher in the gills of mussels from the central clump than in one of the peripheral clump collections. The chemical composition (% water, protein, carbohydrate, lipid and ash) and stable carbon isotope ratios ( ?13C) of the mussels showed the same trends, with highest lipid and carbohydrate and the lowest water content and ?13C in the central site mussels. Similarly, the mussels from the central site were significantly depleted in stable nitrogen ( ?15N) when compared with the peripheral site mussels. Variations between sites and tissues of the same animal may be indicative of differential utilization of inorganic or dissolved molecular nitrogen sources. The condition index (CI = soft tissue dry mass / internal shell volume) was similar for all animals collected at Rose Garden. The presence of a commensal polychaete, Branchipolynoe symmytilida, in the mantle cavity of the mussels was also correlated with the collection site, with the highest incidence of occurrence in the central clump. Levels of the enzyme RuBP carboxylase are quite variable in B. thermophilus and are on the average much lower (0.001 international units) than either Calyptogena magnifica (0.006 I.U.) or Riftia pachyptila (0.16 I.U.). We conclude that the mussels are able to thrive over a wider range of conditions than either C. magnifica or R. pachypila and that this is due to a lesser reliance on their symbiotic bacteria as a source of nutrition.

Fisher, C. R.; Childress, J. J.; Arp, A. J.; Brooks, J. M.; Distel, D.; Favuzzi, J. A.; Felbeck, H.; Hessler, R.; Johnson, K. S.; Kennicutt, M. C.; Macko, S. A.; Newton, A.; Powell, M. A.; Somero, G. N.; Soto, T.

1988-10-01

302

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

303

Diversity and phylogenetic analyses of bacteria from a shallow-water hydrothermal vent in Milos island (Greece)  

PubMed Central

Studies of shallow-water hydrothermal vents have been lagging behind their deep-sea counterparts. Hence, the importance of these systems and their contribution to the local and regional diversity and biogeochemistry is unclear. This study analyzes the bacterial community along a transect at the shallow-water hydrothermal vent system of Milos island, Greece. The abundance and biomass of the prokaryotic community is comparable to areas not affected by hydrothermal activity and was, on average, 1.34 108 cells g?1. The abundance, biomass and diversity of the prokaryotic community increased with the distance from the center of the vent and appeared to be controlled by the temperature gradient rather than the trophic conditions. The retrieved 16S rRNA gene fragments matched sequences from a variety of geothermal environments, although the average similarity was low (94%), revealing previously undiscovered taxa. Epsilonproteobacteria constituted the majority of the population along the transect, with an average contribution to the total diversity of 60%. The larger cluster of 16S rRNA gene sequences was related to chemolithoautotrophic Sulfurovum spp., an Epsilonproteobacterium so far detected only at deep-sea hydrothermal vents. The presence of previously unknown lineages of Epsilonproteobacteria could be related to the abundance of organic matter in these systems, which may support alternative metabolic strategies to chemolithoautotrophy. The relative contribution of Gammaproteobacteria to the Milos microbial community increased along the transect as the distance from the center of the vent increased. Further attempts to isolate key species from these ecosystems will be critical to shed light on their evolution and ecology. PMID:23847607

Giovannelli, Donato; d'Errico, Giuseppe; Manini, Elena; Yakimov, Michail; Vetriani, Costantino

2013-01-01

304

Life and death of deep-sea vents: bacterial diversity and ecosystem succession on inactive hydrothermal sulfides.  

PubMed

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 sulfides--structures that persist for decades to millennia and form moderate to massive deposits at and below the seafloor. Here we used tag pyrosequencing of the V6 region of the 16S rRNA and full-length 16S rRNA sequencing on inactive 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

305

Tidal bottom current modulation of chemical environment in the Suiyo hydrothermal site in the Izu-Ogasawara (Bonin) Arc.  

NASA Astrophysics Data System (ADS)

Intense seafloor observatory studies were done at the Suiyo hydrothermal site in the summer of 2001 and 2002. Deployed instruments on the seafloor were CTD (Idronaut, Ocean Seven 316), Digiquartz precision pressure sensor and its recorder, 3-D acoustic current meters (NOBSKA, MAVS3), high temperature and redox recorders at the vents, in-situ laser particle analyzer (Sequoia Scientific, LISST-Deep), methane sensor (CAPSUM METS) with its data logger, etc. The Suiyo Seamount hydrothermal site is located in the summit caldera of Izu-Ogasawara (Bonin) Arc (1380 m deep, 28.572 N, 140.643 E). The tide is mixed type dominant with semi-diurnal component. There is no tidal components in temperature and redox records neither at high temperature vents (300 deg C) nor at low temperature vents (less than 200 deg C). Whereas the temperature, redox, methane concentration in the seawater, particle characters measured just above the seafloor had strong semi-diurnal components. The methane concentration varies from several micro mol/litter to several tens of micro mol/litter associated with 200 mV redox change in the central part of the hydrothermal site. Semi-diurnal strong bottom current over 40 cm/sec appeared several hours after high tides introduced entrainment of ambient waters in the marginal part of hydrothermal site and accelerated mixing of vent water with bottom water in the central part of the hydrothermal site. This research was funded by the "Archaean Park" Project (International research project on interaction between sub-vent biosphere and geo environment funded by Special Coordination Fund of the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan. The R/V Natsushima cruise with the sub "Shinkai 2000" was a part of the Deep Sea Research project of the Japan Marine Science and Technology Center (JAMSTEC).

Nakamura, K.

2002-12-01

306

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

307

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

308

Microbial community of a hydrothermal mud vent underneath the deep-sea anoxic brine lake Urania (eastern Mediterranean).  

PubMed

The composition of a metabolically active prokaryotic community thriving in hydrothermal mud fluids of the deep-sea hypersaline anoxic Western Urania Basin was characterized using rRNA-based phylogenetic analysis of a clone library. The physiologically active prokaryotic assemblage in this extreme environment showed a great genetic diversity. Most members of the microbial community appeared to be affiliated to yet uncultured organisms from similar ecosystems, i.e., deep-sea hypersaline basins and hydrothermal vents. The bacterial clone library was dominated by phylotypes affiliated with the epsilon-Proteobacteria subdivision recognized as an ecologically significant group of bacteria inhabiting deep-sea hydrothermal environments. Almost 18% of all bacterial clones were related to delta-Proteobacteria, suggesting that sulfate reduction is one of the dominant metabolic processes occurring in warm mud fluids. The remaining bacterial phylotypes were related to alpha- and beta-Proteobacteria, Actinobacteria, Bacteroides, Deinococcus-Thermus, KB1 and OP-11 candidate divisions. Moreover, a novel monophyletic clade, deeply branched with unaffiliated 16S rDNA clones was also retrieved from deep-sea sediments and halocline of Urania Basin. Archaeal diversity was much lower and detected phylotypes included organisms affiliated exclusively with the Euryarchaeota. More than 96% of the archaeal clones belonged to the MSBL-1 candidate order recently found in hypersaline anoxic environments, such as endoevaporitic microbial mats, Mediterranean deep-sea mud volcanoes and anoxic basins. Two phylotypes, represented by single clones were related to uncultured groups DHVE-1 and ANME-1. Thus, the hydrothermal mud of hypersaline Urania Basin seems to contain new microbial diversity. The prokaryotic community was significantly different from that occurring in the upper layers of the Urania Basin since 60% of all bacterial and 40% of all archaeal phylotypes were obtained only from mud fluids. The uniqueness of the composition of the active prokaryotic community could be explained by the complex environmental conditions at the site. The interaction of oxygenated warm mud fluids with the cold hypersaline brine of the Urania Basin seems to simultaneously select for various metabolic processes, such as aerobic and anaerobic heterotrophy, sulfide- and methane-dependent chemotrophy along with anaerobic oxidation of methane, sulfate- and metal-reduction. PMID:17136435

Yakimov, Michail M; Giuliano, Laura; Cappello, Simone; Denaro, Renata; Golyshin, Peter N

2007-04-01

309

Microbial Community of a Hydrothermal Mud Vent Underneath the Deep-Sea Anoxic Brine Lake Urania (Eastern Mediterranean)  

NASA Astrophysics Data System (ADS)

The composition of a metabolically active prokaryotic community thriving in hydrothermal mud fluids of the deep-sea hypersaline anoxic Western Urania Basin was characterized using rRNA-based phylogenetic analysis of a clone library. The physiologically active prokaryotic assemblage in this extreme environment showed a great genetic diversity. Most members of the microbial community appeared to be affiliated to yet uncultured organisms from similar ecosystems, i.e., deep-sea hypersaline basins and hydrothermal vents. The bacterial clone library was dominated by phylotypes affiliated with the epsilon- Proteobacteria subdivision recognized as an ecologically significant group of bacteria inhabiting deep-sea hydrothermal environments. Almost 18% of all bacterial clones were related to delta- Proteobacteria, suggesting that sulfate reduction is one of the dominant metabolic processes occurring in warm mud fluids. The remaining bacterial phylotypes were related to alpha- and beta- Proteobacteria, Actinobacteria, Bacteroides, Deinococcus-Thermus, KB1 and OP-11 candidate divisions. Moreover, a novel monophyletic clade, deeply branched with unaffiliated 16S rDNA clones was also retrieved from deep-sea sediments and halocline of Urania Basin. Archaeal diversity was much lower and detected phylotypes included organisms affiliated exclusively with the Euryarchaeota. More than 96% of the archaeal clones belonged to the MSBL-1 candidate order recently found in hypersaline anoxic environments, such as endoevaporitic microbial mats, Mediterranean deep-sea mud volcanoes and anoxic basins. Two phylotypes, represented by single clones were related to uncultured groups DHVE-1 and ANME-1. Thus, the hydrothermal mud of hypersaline Urania Basin seems to contain new microbial diversity. The prokaryotic community was significantly different from that occurring in the upper layers of the Urania Basin since 60% of all bacterial and 40% of all archaeal phylotypes were obtained only from mud fluids. The uniqueness of the composition of the active prokaryotic community could be explained by the complex environmental conditions at the site. The interaction of oxygenated warm mud fluids with the cold hypersaline brine of the Urania Basin seems to simultaneously select for various metabolic processes, such as aerobic and anaerobic heterotrophy, sulfide- and methane-dependent chemotrophy along with anaerobic oxidation of methane, sulfate- and metal-reduction.

Yakimov, Michail M.; Giuliano, Laura; Cappello, Simone; Denaro, Renata; Golyshin, Peter N.

2007-04-01

310

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

311

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

312

Tectonic/volcanic segmentation and controls on hydrothermal venting along Earth's fastest seafloor spreading system, EPR 27-32S  

NASA Astrophysics Data System (ADS)

We have collected 12 kHz SeaBeam bathymetry and 120 kHz DSL-120 side-scan sonar and bathymetry data to determine the tectonic and volcanic segmentation along the fastest spreading (150 km/Myr) part of the global mid-ocean ridge system, the southern East Pacific Rise between the Easter and Juan Fernandez microplates. This area is presently reorganizing by large-scale dueling rift propagation and possible protomicroplate tectonics. Fracture patterns observed in the side-scan data define structural segmentation scales along these ridge segments. These sometimes, but not always, correlate with linear volcanic systems defining segmentation in the SeaBeam data. Some of the subsegments behave cohesively, with in-phase tectonic activity, while fundamental discontinuities occur between other subsegments. We also collected hydrothermal plume data using sensors mounted on the DSL-120 instrument package, as well as CTDO tow-yos, to determine detailed structural and volcanic controls on the hydrothermal vent pattern observed along 600 km of the Pacific-Nazca axis. Here we report the first rigorous correlation between coregistered hydrothermal plume and high-resolution marine geophysical data on similar scales and over multisegment distances. Major plume concentrations were usually found where axial inflation was relatively high and fracture density was relatively low. These correlations suggest that hydrothermal venting is most active where the apparent magmatic budget is greatest, resulting in recent eruptions that have paved over the neovolcanic zone. Areas of voluminous acoustically dark young lava flows produced from recent fissure eruptions correlate with many of the major hydrothermal vent areas. Increased crustal permeability, as gauged by increased fracture density, does not enhance hydrothermal venting in this area. Axial summit troughs and graben are rare, probably because of frequent volcanic resurfacing in this superfast spreading environment, and are not good predictors of hydrothermal activity here. Many of the hydrothermal areas are found in inflated areas near the ends of segments, suggesting that abundant magma is being supplied to these areas.

Hey, Richard; Baker, Edward; Bohnenstiehl, Delwayne; Massoth, Gary; Kleinrock, Martin; Martinez, Fernando; Naar, David; Pardee, Debra; Lupton, John; Feely, Richard; Gharib, Jim; Resing, Joe; Rodrigo, Cristian; Sansone, Francis; Walker, Sharon

2004-12-01

313

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

314

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

315

Prokaryote Diversity and Virus Abundance in Shallow Hydrothermal Vents of the Mediterranean Sea (Panarea Island) and the Pacific Ocean (North Sulawesi-Indonesia)  

Microsoft Academic Search

Despite their ubiquitous distribution in tectonically active coastal zones, shallow water hydrothermal vents have been less\\u000a investigated than deep-sea vents. In the present study, we investigated the role of viral control and fluid emissions on prokaryote\\u000a abundance, diversity, and community structure (total Archaea, total Bacteria, and sulphate-reducing bacteria) in waters and\\u000a sediments surrounding the caldera of four different shallow-water hydrothermal

E. Manini; G. M. Luna; C. Corinaldesi; D. Zeppilli; G. Bortoluzzi; G. Caramanna; F. Raffa; R. Danovaro

2008-01-01

316

Pathways of Carbon and Energy Metabolism of the Epibiotic Community Associated with the Deep-Sea Hydrothermal Vent Shrimp Rimicaris exoculata  

PubMed Central

Background The shrimp Rimicaris exoculata dominates the faunal biomass at many deep-sea hydrothermal vent sites at the Mid-Atlantic Ridge. In its enlarged gill chamber it harbors a specialized epibiotic bacterial community for which a nutritional role has been proposed. Methodology/Principal Findings We analyzed specimens from the Snake Pit hydrothermal vent field on the Mid-Atlantic Ridge by complementing a 16S rRNA gene survey with the analysis of genes involved in carbon, sulfur and hydrogen metabolism. In addition to Epsilon- and Gammaproteobacteria, the epibiotic community unexpectedly also consists of Deltaproteobacteria of a single phylotype, closely related to the genus Desulfocapsa. The association of these phylogenetic groups with the shrimp was confirmed by fluorescence in situ hybridization. Based on functional gene analyses, we hypothesize that the Gamma- and Epsilonproteobacteria are capable of autotrophic growth by oxidizing reduced sulfur compounds, and that the Deltaproteobacteria are also involved in sulfur metabolism. In addition, the detection of proteobacterial hydrogenases indicates the potential for hydrogen oxidation in these communities. Interestingly, the frequency of these phylotypes in 16S rRNA gene clone libraries from the mouthparts differ from that of the inner lining of the gill chamber, indicating potential functional compartmentalization. Conclusions Our data show the specific association of autotrophic bacteria with Rimicaris exoculata from the Snake Pit hydrothermal vent field, and suggest that autotrophic carbon fixation is contributing to the productivity of the epibiotic community with the reductive tricarboxylic acid cycle as one important carbon fixation pathway. This has not been considered in previous studies of carbon fixation and stable carbon isotope composition of the shrimp and its epibionts. Furthermore, the co-occurrence of sulfur-oxidizing and sulfur-reducing epibionts raises the possibility that both may be involved in the syntrophic exchange of sulfur compounds, which could increase the overall efficiency of this epibiotic community. PMID:21249205

Hgler, Michael; Petersen, Jillian M.; Dubilier, Nicole; Imhoff, Johannes F.; Sievert, Stefan M.

2011-01-01

317

Two novel hepatocellular carcinoma cycle inhibitory cyclodepsipeptides from a hydrothermal vent crab-associated fungus Aspergillus clavatus C2WU.  

PubMed

Two novel cyclodepsipeptides containing an unusual anthranilic acid dimer and a D-phenyllactic acid residues, clavatustides A and B, were identified from cultured mycelia and broth of Aspergillus clavatus C2WU isolated from Xenograpsus testudinatus, which lives at extreme, toxic habitat around the sulphur-rich 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 and B suppressed the proliferation of hepatocellular carcinoma (HCC) cell lines (HepG2, SMMC-7721 and Bel-7402) in a dose-dependent manner, and induced an accumulation of HepG2 cells in G1 phase and reduction of cells in S phase. PMID:24317468

Jiang, Wei; Ye, Panpan; Chen, Chen-Tung Arthur; Wang, Kuiwu; Liu, Pengyuan; He, Shan; Wu, Xiaodan; Gan, Lishe; Ye, Ying; Wu, Bin

2013-12-01

318

Draft genome sequence of Caminibacter mediatlanticus strain TB-2, an epsilonproteobacterium isolated from a deep-sea hydrothermal vent.  

PubMed

Caminibacter mediatlanticus strain TB-2(T) [1], is a thermophilic, anaerobic, chemolithoautotrophic bacterium, isolated from the walls of an active deep-sea hydrothermal vent chimney on the Mid-Atlantic Ridge and the type strain of the species. C. mediatlanticus is a Gram-negative member of the Epsilonproteobacteria (order Nautiliales) that grows chemolithoautotrophically with H(2) as the energy source and CO(2) as the carbon source. Nitrate or sulfur is used as the terminal electron acceptor, with resulting production of ammonium and hydrogen sulfide, respectively. In view of the widespread distribution, importance and physiological characteristics of thermophilic Epsilonproteobacteria in deep-sea geothermal environments, it is likely that these organisms provide a relevant contribution to both primary productivity and the biogeochemical cycling of carbon, nitrogen and sulfur at hydrothermal vents. Here we report the main features of the genome of C. mediatlanticus strain TB-2(T). PMID:22180817

Giovannelli, Donato; Ferriera, Steven; Johnson, Justin; Kravitz, Saul; Prez-Rodrguez, Ileana; Ricci, Jessica; O'Brien, Charles; Voordeckers, James W; Bini, Elisabetta; Vetriani, Costantino

2011-10-15

319

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

320

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

321

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

322

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

323

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

324

Dynamics of cell proliferation and apoptosis reflect different life strategies in hydrothermal vent and cold seep vestimentiferan tubeworms  

Microsoft Academic Search

Deep-sea vestimentiferan tubeworms, which live in symbiosis with bacteria, exhibit different life strategies according to\\u000a their habitat. At unstable and relatively short-lived hydrothermal vents, they grow extremely fast, whereas their close relatives\\u000a at stable and long-persisting cold seeps grow slowly and live up to 300years. Growth and age differences are thought to occur\\u000a because of ecological and physiological adaptations. However,

Bettina Pflugfelder; S. Craig Cary; Monika Bright

2009-01-01

325

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

326

Nitrogen Reduction Under Hydrothermal Vent Conditions: Implications for the Prebiotic Synthesis of C-H-O-N Compounds  

NASA Astrophysics Data System (ADS)

Dinitrogen is reduced in dilute hydrogen sulfide (H2S) solutions to ammonium at 120C. Experiments with dissolved dinitrogen (partial pressure 50 bar) in a 12 10-3 mol/L H2S(aq) solution yield ~10-5 mol/L NH4+ within 2-7 days. These yields are consistent with the equilibrium NH4+ concentration for the N-S-H system under these conditions. The formation of ammonium is catalyzed by the presence of freshly precipitated iron monosulfide. These results indicate that dinitrogen can be reduced at moderate temperatures in hydrothermal vent systems. Abiotic nitrogen reduction could have taken place within primordial hydrothermal vents, supplying some ammonia for the synthesis of C-H-O-N compounds via abiotic processes. The yield of ammonia via dinitrogen reduction by hydrogen sulfide, however, is so low that it is doubtful this process could have produced enough ammonia to sustain prebiotic hydrothermal synthesis of C-H-O-N compounds in or around vent systems.

Schoonen, Martin A. A.; Xu, Yong

2001-06-01

327

Nitrogen reduction under hydrothermal vent conditions: implications for the prebiotic synthesis of C-H-O-N compounds.  

PubMed

Dinitrogen is reduced in dilute hydrogen sulfide (H2S) solutions to ammonium at 120 degrees C. Experiments with dissolved dinitrogen (partial pressure 50 bar) in a 12 x 10(-3) mol/L H2S(aq) solution yield approximately 10(-5) mol/L NH4+ within 2-7 days. These yields are consistent with the equilibrium NH4+ concentration for the N-S-H system under these conditions. The formation of ammonium is catalyzed by the presence of freshly precipitated iron monosulfide. These results indicate that dinitrogen can be reduced at moderate temperatures in hydrothermal vent systems. Abiotic nitrogen reduction could have taken place within primordial hydrothermal vents, supplying some ammonia for the synthesis of C-H-O-N compounds via abiotic processes. The yield of ammonia via dinitrogen reduction by hydrogen sulfide, however, is so low that it is doubtful this process could have produced enough ammonia to sustain prebiotic hydrothermal synthesis of C-H-O-N compounds in or around vent systems. PMID:12467117

Schoonen, M A; Xu, Y

2001-01-01

328

Fluid flow and mass flux determinations at vent sites on the Cascadia margin accretionary prism  

Microsoft Academic Search

Fluid venting from the toe of the accretionary prism off Oregon was measured in situ during a series of dives with DSRV Alvin in 1987 and 1988. A benthic chamber was placed over active vent sites to sequentially collect samples of venting fluids and to make direct measurements of discharge rates. Calibrated flow meter measurements and flow rates determined from

Bobb Carson; Erwin Suess; Jeffrey C. Strasser

1990-01-01

329

Modeling fluid flow in sedimentary basins with sill intrusions: Implications for hydrothermal venting and climate change  

NASA Astrophysics Data System (ADS)

Large volumes of magma emplaced within sedimentary basins have been linked to multiple climate change events due to release of greenhouse gases such as CH4. Basin-scale estimates of thermogenic methane generation show that this process alone could generate enough greenhouse gases to trigger global incidents. However, the rates at which these gases are transported and released into the atmosphere are quantitatively unknown. We use a 2D, hybrid FEM/FVM model that solves for fully compressible fluid flow to quantify the thermogenic release and transport of methane and to evaluate flow patterns within these systems. Our results show that the methane generation potential in systems with fluid flow does not significantly differ from that estimated in diffusive systems. The values diverge when vigorous convection occurs with a maximum variation of about 50%. The fluid migration pattern around a cooling, impermeable sill alone generates hydrothermal plumes without the need for other processes such as boiling and/or explosive degassing. These fluid pathways are rooted at the edges of the outer sills consistent with seismic imaging. Methane venting at the surface occurs in three distinct stages and can last for hundreds of thousands of years. Our simulations suggest that although the quantity of methane potentially generated within the contact aureole can cause catastrophic climate change, the rate at which this methane is released into the atmosphere is too slow to trigger, by itself, some of the negative ?13C excursions observed in the fossil record over short time scales (<10,000 years).

Iyer, Karthik; Rpke, Lars; Galerne, Christophe Y.

2013-12-01

330

The biological deep sea hydrothermal vent as a model to study carbon dioxide capturing enzymes.  

PubMed

Deep sea hydrothermal vents are located along the mid-ocean ridge system, near volcanically active areas, where tectonic plates are moving away from each other. Sea water penetrates the fissures of the volcanic bed and is heated by magma. This heated sea water rises to the surface dissolving large amounts of minerals which provide a source of energy and nutrients to chemoautotrophic organisms. Although this environment is characterized by extreme conditions (high temperature, high pressure, chemical toxicity, acidic pH and absence of photosynthesis) a diversity of microorganisms and many animal species are specially adapted to this hostile environment. These organisms have developed a very efficient metabolism for the assimilation of inorganic CO? from the external environment. In order to develop technology for the capture of carbon dioxide to reduce greenhouse gases in the atmosphere, enzymes involved in CO? fixation and assimilation might be very useful. This review describes some current research concerning CO? fixation and assimilation in the deep sea environment and possible biotechnological application of enzymes for carbon dioxide capture. PMID:21673885

Minic, Zoran; Thongbam, Premila D

2011-01-01

331

The Biological Deep Sea Hydrothermal Vent as a Model to Study Carbon Dioxide Capturing Enzymes  

PubMed Central

Deep sea hydrothermal vents are located along the mid-ocean ridge system, near volcanically active areas, where tectonic plates are moving away from each other. Sea water penetrates the fissures of the volcanic bed and is heated by magma. This heated sea water rises to the surface dissolving large amounts of minerals which provide a source of energy and nutrients to chemoautotrophic organisms. Although this environment is characterized by extreme conditions (high temperature, high pressure, chemical toxicity, acidic pH and absence of photosynthesis) a diversity of microorganisms and many animal species are specially adapted to this hostile environment. These organisms have developed a very efficient metabolism for the assimilation of inorganic CO2 from the external environment. In order to develop technology for the capture of carbon dioxide to reduce greenhouse gases in the atmosphere, enzymes involved in CO2 fixation and assimilation might be very useful. This review describes some current research concerning CO2 fixation and assimilation in the deep sea environment and possible biotechnological application of enzymes for carbon dioxide capture. PMID:21673885

Minic, Zoran; Thongbam, Premila D.

2011-01-01

332

Identity and mechanisms of alkane-oxidizing metalloenzymes from deep-sea hydrothermal vents  

PubMed Central

Six aerobic alkanotrophs (organism that can metabolize alkanes as their sole carbon source) isolated from deep-sea hydrothermal vents were characterized using the radical clock substrate norcarane to determine the metalloenzyme and reaction mechanism used to oxidize alkanes. The organisms studied were Alcanivorax sp. strains EPR7 and MAR14, Marinobacter sp. strain EPR21, Nocardioides sp. strains EPR26w, EPR28w, and Parvibaculum hydrocarbonoclasticum strain EPR92. Each organism was able to grow on n-alkanes as the sole carbon source and therefore must express genes encoding an alkane-oxidizing enzyme. Results from the oxidation of the radical-clock diagnostic substrate norcarane demonstrated that five of the six organisms (EPR7, MAR14, EPR21, EPR26w, and EPR28w) used an alkane hydroxylase functionally similar to AlkB to catalyze the oxidation of medium-chain alkanes, while the sixth organism (EPR92) used an alkane-oxidizing cytochrome P450 (CYP)-like protein to catalyze the oxidation. DNA sequencing indicated that EPR7 and EPR21 possess genes encoding AlkB proteins, while sequencing results from EPR92 confirmed the presence of a gene encoding CYP-like alkane hydroxylase, consistent with the results from the norcarane experiments. PMID:23825470

Bertrand, Erin M.; Keddis, Ramaydalis; Groves, John T.; Vetriani, Costantino; Austin, Rachel Narehood

2013-01-01

333

Molecular Identification and Localization of Filamentous Symbiotic Bacteria Associated with the Hydrothermal Vent Annelid Alvinella pompejana  

PubMed Central

Alvinella pompejana is 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 prominent filamentous 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 a clone library of 16S rRNA genes amplified by PCR from the epibiotic microbial community of an A. pompejana specimen. In the present study deoxyoligonucleotide PCR primers specific for phylotypes 13B and 5A were used to demonstrate that these phylotypes are regular features of the bacterial community associated with A. pompejana. Assaying of other surfaces around colonies of A. pompejana revealed that phylotypes 13B and 5A are not restricted to A. pompejana. Phylotype 13B occurs on the exterior surfaces of other invertebrate genera and rock surfaces, and phylotype 5A occurs on a congener, Alvinella caudata. The 13B and 5A phylotypes were identified and localized on A. pompejana by in situ hybridization, demonstrating that these two phylotypes are, in fact, the prominent filamentous bacteria on the dorsal integument of A. pompejana. These findings indicate that the filamentous bacterial symbionts of A. pompejana are epsilon Proteobacteria which do not have an obligate requirement for A. pompejana. PMID:16535543

Cary, S. C.; Cottrell, M. T.; Stein, J. L.; Camacho, F.; Desbruyeres, D.

1997-01-01

334

New insights into hydrothermal vent processes in the unique shallow-submarine arc-volcano, Kolumbo (Santorini), Greece  

PubMed Central

We report on integrated geomorphological, mineralogical, geochemical and biological investigations of the hydrothermal vent field located on the floor of the density-stratified acidic (pH ~ 5) crater of the Kolumbo shallow-submarine arc-volcano, near Santorini. Kolumbo features rare geodynamic setting at convergent boundaries, where arc-volcanism and seafloor hydrothermal activity are occurring in thinned continental crust. Special focus is given to unique enrichments of polymetallic spires in Sb and Tl (Hg, As, Au, Ag, Zn) indicating a new hybrid seafloor analogue of epithermal-to-volcanic-hosted-massive-sulphide deposits. Iron microbial-mat analyses reveal dominating ferrihydrite-type phases, and high-proportion of microbial sequences akin to "Nitrosopumilus maritimus", a mesophilic Thaumarchaeota strain capable of chemoautotrophic growth on hydrothermal ammonia and CO2. Our findings highlight that acidic shallow-submarine hydrothermal vents nourish marine ecosystems in which nitrifying Archaea are important and suggest ferrihydrite-type Fe3+-(hydrated)-oxyhydroxides in associated low-temperature iron mats are formed by anaerobic Fe2+-oxidation, dependent on microbially produced nitrate. PMID:23939372

Kilias, Stephanos P.; Nomikou, Paraskevi; Papanikolaou, Dimitrios; Polymenakou, Paraskevi N.; Godelitsas, Athanasios; Argyraki, Ariadne; Carey, Steven; Gamaletsos, Platon; Mertzimekis, Theo J.; Stathopoulou, Eleni; Goettlicher, Joerg; Steininger, Ralph; Betzelou, Konstantina; Livanos, Isidoros; Christakis, Christos; Bell, Katherine Croff; Scoullos, Michael

2013-01-01

335

Fluid chemistry of Archean seafloor hydrothermal vents: Implications for the composition of circa 3.2 Ga seawater  

NASA Astrophysics Data System (ADS)

Seafloor hydrothermal vents of mid-Archean age (ca. 3230 Ma) have been identified and mapped in the Barberton greenstone belt, South Africa and are known as the Ironstone Pods. Fluid inclusion homogenization temperature data, when combined with gas chromatographic data, provide a minimum calculated water depth for the pods of 982 m. Ironstone Pod hydrothermal fluid endmember concentrations (Mg = 0) of various dissolved components derived from bulk fluid inclusion crush-leach experiments, include: Cl(730 mmol/L), Br (2.59), I (0.058), Na (822), NH 4 (11.4), K (21.5), Ca (42.6), and Sr (0.15). This hydrothermal fluid also contains up to 1.07 mol% CO 2, 0.03 mol% N 2, 0.02 mol% CH 4, 262 ppm COS, and minor amounts of C2-C4 hydrocarbons. Hydrothermal endmember Ca, Sr, and NH 4, in particular, and to a lesser degree K, I, and CO 2, commonly plot on, or very close to, modern vent fluid trends. By contrast, endmember Na and Br concentrations are distinct (higher) from modern vent fluids. High I and NH 4 concentrations are consistent with contributions from sediments and/or organic matter. Calculated ?18O H 2O values for the pod hydrothermal endmember fluid define a narrow range from 0.9 to 1.6 very similar to that of modern vent fluid values (0.4-2.1). A best estimate for the Ironstone Pod seawater endmember composition is Cl (920 mmol/L), Br (2.25), SO 4 (2.3), I (0.037), Na (789), NH 4 (5.1), K (18.9), Mg (50.9), Ca (232), and Sr (4.52). Barberton seawater components are commonly within an order of magnitude of modern seawater values, with the exception of significantly higher 1, NH 4, Ca, and Sr in the inclusions. Sulfate concentrations are minimum estimates for Barberton seawater. Fluid inclusion samples containing the greatest amount of seawater component have higher N 2 (up to 0.1 mol%) and low CO 2, when compared to samples dominated by the hydrothermal endmember fluid. Barberton ambient seawater is considered to have been an evaporative brine of NaCl?CaCl 2 composition during the time of pod deposition. Ironstone Pod fluid inclusion seawater endmember Br/Cl and I/Cl values of 2.45 10 -3 and 40.2 10 -6, respectively, are within error of bulk Earth (2.38 10 -3 and 190 10 -6) and are consistent with the chemistry of 3.23 Ga Barberton seawater being buffered by the mantle.

De Ronde, Cornel E. J.; Channer, Dominic M. deR.; Faure, Kevin; Bray, Colin J.; Spooner, Edward T. C.

1997-10-01

336

Hydrothermal Activity on the Mid-Cayman Rise: ROV Jason sampling and site characterization at the Von Damm and Piccard hydrothermal fields  

NASA Astrophysics Data System (ADS)

In January 2012 our multi-national and multi-disciplinary team conducted a series of 10 ROV Jason dives to conduct first detailed and systematic sampling of the Mid Cayman Rise hydrothermal systems at the Von Damm and Piccard hydrothermal fields. At Von Damm, hydrothermal venting is focused at and around a large conical structure that is approximately 120 m in diameter and rises at least 80m from the surrounding, largely sedimented seafloor. Clear fluids emitted from multiple sites around the flanks of the mound fall in the temperature range 110-130C and fall on a common mixing line with hotter (>200C) clear fluids emitted from an 8m tall spire at the summit which show clear evidence of ultramafic influence. Outcrop close to the vent-site is rare and the cone itself appear to consist of clay minerals derived from highly altered host rock. The dominant fauna at the summit of Von Damm are a new species of chemosynthetic shrimp but elsewhere the site also hosts two distinct species of chemosynthetic tube worm as well as at least one species of gastropod. The adjacent Piccard site, at ~5000m depth comprises 7 distinct sulfide mounds, 3 of which are currently active: Beebe Vents, Beebe Woods and Beebe Sea. Beebe Vents consists of 5 vigorous black smoker chimneys with maximum temperatures in the range 400-403C while at Beebe Woods a more highly colonized thicket of up to 8m tall chimneys includes predominantly beehive diffusers with rare black smokers emitting fluids up to 353C. Beebe Sea a diffuse site emitting fluids at 38C Tmax, is the largest of the currently active mounds and immediately abuts a tall (8m) rift that strikes NE-SW bisecting the host Axial Volcanic Ridge. The fauna at Piccard are less diverse than at Von Damm and, predominantly, comprise the same species of MCR shrimp, a distinct gastropod species and abundant anemones.

German, C. R.

2012-12-01

337

Insights into Spatial Sulfur Variation within the Modified Gill-Chamber of the Epibiont-Colonized Hydrothermal Vent Shrimp, Rimicaris exoculata  

NASA Astrophysics Data System (ADS)

Rimicaris exoculata dominates the megafaunal biomass at numerous Mid-Atlantic hydrothermal vents. Within the gill chamber of the shrimp exists a rich epibiotic community. These shrimp swarm around active black smoker chimneys at the Snake Pit vent site on the Mid-Atlantic Ridge, and have been hypothesized to utilize the mixing zone between ambient seawater and hydrothermal fluid to supply these epibionts with a redox environment suitable for the promotion of chemoautotrophic growth. Investigation of the oxidation state, distribution, and concentration of sulfur of different compartments within the shrimp's gill chamber was conducted using synchrotron-based micro-X-ray fluorescence (micro-XRF) and micro-X-ray Absorption Near Edge Structure (micro-XANES) spectroscopy. Principle component analysis of point XANES spectra yielded four reference components indentified as elemental sulfur, sulfate, monosulfide (likely iron sulfide), and an organosulfur thiol compound. Energy specific micro-XRF mapping of these reference components in both the modified mouthparts and inner lining of the carapace enclosing the gill chamber displayed spatial heterogeneity in sulfur oxidation state and coordination. Sulfate, organosulfur thiol compounds, and phosphate tended to correlate with chitin structural features, while elemental sulfur was concentrated in areas where epibionts were observed. DNA extraction and sequencing from epibiont populations within each of the modified mouthparts and carapace was conducted to provide insight into the community structure at each of these distinct areas of the gill chamber. Here we demonstrate the complexity of sulfur speciation and mineralization in association with the host epibiont community composition.

Rempfert, K. R.; Sievert, S. M.; Hansel, C. M.; Webb, S. M.; Thomas, F.

2013-12-01

338

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

PubMed Central

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 the accumulation of metallic tellurium or selenium. The MIC of K2TeO3 ranged from 1,500 to greater than 2,500 ?g/ml, and the MIC of Na2SeO3 ranged from 6,000 to greater than 7,000 ?g/ml for 10 strains. Phylogenetic analysis of 4 of these 10 strains revealed that they form a branch closely related to members of the genus Pseudoalteromonas, within the ?-3 subclass of the Proteobacteria. All 10 strains were found to be salt tolerant, pH tolerant, and thermotolerant. The metalloid resistance and morphological, physiological, and phylogenetic characteristics of newly isolated strains are described. PMID:12200320

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

2002-01-01

339

Prokaryote diversity and virus abundance in shallow hydrothermal vents of the Mediterranean Sea (Panarea Island) and the Pacific Ocean (north Sulawesi-Indonesia).  

PubMed

Despite their ubiquitous distribution in tectonically active coastal zones, shallow water hydrothermal vents have been less investigated than deep-sea vents. In the present study, we investigated the role of viral control and fluid emissions on prokaryote abundance, diversity, and community structure (total Archaea, total Bacteria, and sulphate-reducing bacteria) in waters and sediments surrounding the caldera of four different shallow-water hydrothermal vents (three located in the Mediterranean Sea and one in the Pacific Ocean). All vents, independent of their location, generally displayed a significant decrease of benthic prokaryote abundance, as well as its viable fraction, with increasing distance from the vent. Prokaryote assemblages were always dominated by Bacteria. Benthic Archaea accounted for 23-33% of total prokaryote abundance in the Mediterranean Sea and from 13 to 29% in the Pacific Ocean, whereas in the water column they accounted for 25-38%. The highest benthic bacterial ribotype richness was observed in close proximity of the vents (i.e., at 10-cm distance from the emissions), indicating that vent fluids might influence bacterial diversity in surrounding sediments. Virioplankton and viriobenthos abundances were low compared to other marine systems, suggesting that temperature and physical-chemical conditions might influence viral survival in these vent systems. We thus hypothesize that the high bacterial diversity observed in close proximity of the vents is related with the highly variable vent emissions, which could favor the coexistence of several prokaryotic species. PMID:17687593

Manini, E; Luna, G M; Corinaldesi, C; Zeppilli, D; Bortoluzzi, G; Caramanna, G; Raffa, F; Danovaro, R

2008-05-01

340

A hybrid zone between Bathymodiolus mussel lineages from eastern Pacific hydrothermal vents  

PubMed Central

Background The inhabitants of deep-sea hydrothermal vents occupy ephemeral island-like habitats distributed sporadically along tectonic spreading-centers, back-arc basins, and volcanically active seamounts. The majority of vent taxa undergo a pelagic larval phase, and thus varying degrees of geographical subdivision, ranging from no impedance of dispersal to complete isolation, often exist among taxa that span common geomorphological boundaries. Two lineages of Bathymodiolus mussels segregate on either side of the Easter Microplate, a boundary that separates the East Pacific Rise from spreading centers connected to the Pacific-Antarctic Ridge. Results A recent sample from the northwest flank of the Easter Microplate contained an admixture of northern and southern mitochondrial haplotypes and corresponding alleles at five nuclear gene loci. Genotypic frequencies in this sample did not fit random mating expectation. Significant heterozygote deficiencies at nuclear loci and gametic disequilibria between loci suggested that this transitional region might be a Tension Zone maintained by immigration of parental types and possibly hybrid unfitness. An analysis of recombination history in the nuclear genes suggests a prolonged history of parapatric contact between the two mussel lineages. We hereby elevate the southern lineage to species status as Bathymodiolus antarcticus n. sp. and restrict the use of Bathymodiolus thermophilus to the northern lineage. Conclusions Because B. thermophilus s.s. exhibits no evidence for subdivision or isolation-by-distance across its 4000 km range along the EPR axis and Galpagos Rift, partial isolation of B. antarcticus n. sp. requires explanation. The time needed to produce the observed degree of mitochondrial differentiation is consistent with the age of the Easter Microplate (2.5 to 5.3 million years). The complex geomorphology of the Easter Microplate region forces strong cross-axis currents that might disrupt self-recruitment of mussels by removing planktotrophic larvae from the ridge axis. Furthermore, frequent local extinction events in this tectonically dynamic region might produce a demographic sink rather than a source for dispersing mussel larvae. Historical changes in tectonic rates and current patterns appear to permit intermittent contact and introgression between the two species. PMID:23347448

2013-01-01

341

Hydrothermal Vents and Organic Falls in the Heart of the Coral Triangle: Chemosynthetic Communities Discovered via Telepresence in the Sangihe-Talaud Region, Northern Sulawesi, Indonesia  

NASA Astrophysics Data System (ADS)

From June to August 2010, an international partnership of scientists and engineers from the United States, Canada, and Indonesia utilized the NOAA Ship Okeanos Explorer and HD video from the ROV Little Herc to explore virtually unknown deep seafloor in the heart of the Coral Triangle. The INDEX-SATAL 2010 expedition bathymetrically mapped more than 39,000sq km of the Sangihe-Talaud region, including several discrete volcanic cones on the western flank of the Sangihe Arc. Twenty sites between 275m and 3650m were explored during 27 ROV dives, including the first (and only) known hydrothermally-active site (1850m) in the Indonesian region, Kawio Barat, a volcanically active seamount hosting chemosynthetic ecosystems. The dominant fauna inhabiting hydrothermally-active areas were: 1) three shrimp morpho-species resembling Opaepele sp. and Chorocaris sp., intermingling on the sides of active smokers, amongst stalked barnacles, and scraping mineral surfaces; 2) large (10cm-long) polynoid scale worms (aff Branchinotogluma sp.) meandering through diffuse venting and within barnacle assemblages; 3) discrete patches of tube-dwelling alvinellid polychaetes, and perhaps the most dominant, stalked Vulcanolepas barnacles, densely packed at the base of individual spires, as well as completely carpeting 3 to 4m-tall inactive chimneys on the summit crest of the seamount, particularly above the main group of active chimneys. Brachyuran and galatheid crabs were observed amongst stalked barnacles and in sulfide crevices. Vesicoymid-like clams (5 to 10cm long) were observed on the surface of volcanoclastic and pelagic sediment 50 to 125m down slope of the active venting. Other potentially chemosynthetic habitats were observed at several sites, including wooden logs and coconut shells. For example, the sedimented slopes of Seamount G (1926m) and flats of Memeridge (3600m) contained a notable lack of epibenthic fauna with the notable exception of frequent wood falls inhabited by a distinctive fauna: tubeworms, urchins, amphipods, galatheid crabs, serpulid worms and gastropod limpets, likely attracted by the organic enrichment. The fauna inhabiting Kawio Barat and these wood falls were markedly dissimilar. Recent molecular studies show that some of the fauna of hydrothermal vents and organic falls have disparate physiological adaptations yet shared evolutionary histories, changing our view of evolution in the deep sea. These relationships as well as the potential isolation of Indonesian fauna to those inhabiting other chemosynthetic seamounts and sites in the western Pacific will be discussed.

Shank, T. M.; Herrera, S.; Bors, E.; Munro, C.; Sibert, E.; Nganro, N.; Makarim, S.; Wirasantosa, S.; Tunnicliffe, V.; Baker, E. T.; Butterfield, D. A.; Holden, J. F.; Hammond, S. R.

2010-12-01

342

A Mossbauer investigation of iron-rich terrestrial hydrothermal vent systems: lessons for Mars exploration  

NASA Technical Reports Server (NTRS)

Hydrothermal spring systems may well have been present on early Mars and could have served as a habitat for primitive life. The integrated instrument suite of the Athena Rover has, as a component on the robotic arm, a Mossbauer spectrometer. In the context of future Mars exploration we present results of Mossbauer analysis of a suite of samples from an iron-rich thermal spring in the Chocolate Pots area of Yellowstone National Park (YNP) and from Obsidian Pool (YNP) and Manitou Springs, Colorado. We have found that Mossbauer spectroscopy can discriminate among the iron-bearing minerals in our samples. Those near the vent and on the surface are identified as ferrihydrite, an amorphous ferric mineraloid. Subsurface samples, collected from cores, which are likely to have undergone inorganic and/or biologically mediated alteration (diagenesis), exhibit spectral signatures that include nontronite (a smectite clay), hematite (alpha-Fe2O3), small-particle/nanophase goethite (alpha-FeOOH), and siderite (FeCO3). We find for iron minerals that Mossbauer spectroscopy is at least as efficient in identification as X-ray diffraction. This observation is important from an exploration standpoint. As a planetary surface instrument, Mossbauer spectroscopy can yield high-quality spectral data without sample preparation (backscatter mode). We have also used field emission scanning electron microscopy (FESEM), in conjunction with energy-dispersive X ray (EDX) fluorescence spectroscopy, to characterize the microbiological component of surface sinters and the relation between the microbiological and the mineralogical framework. Evidence is presented that the minerals found in these deposits can have multi-billion-year residence times and thus may have survived their possible production in a putative early Martian hot spring up to the present day. Examples include the nanophase property and the Mossbauer signature for siderite, which has been identified in a 2.09-billion-year old hematite-rich chert stromatolite. Our research demonstrates that in situ Mossbauer spectroscopy can help determine whether hydrothermal mineral deposits exist on Mars, which is significant for exobiology because of the issue of whether that world ever had conditions conductive to the origin of life. As a useful tool for selection of samples suitable for transport to Earth, Mossbauer spectroscopy will not only serve geological interests but will also have potential for exopaleontology.

Wade, M. L.; Agresti, D. G.; Wdowiak, T. J.; Armendarez, L. P.; Farmer, J. D.

1999-01-01

343

A Mossbauer investigation of iron-rich terrestrial hydrothermal vent systems: lessons for Mars exploration.  

PubMed

Hydrothermal spring systems may well have been present on early Mars and could have served as a habitat for primitive life. The integrated instrument suite of the Athena Rover has, as a component on the robotic arm, a Mossbauer spectrometer. In the context of future Mars exploration we present results of Mossbauer analysis of a suite of samples from an iron-rich thermal spring in the Chocolate Pots area of Yellowstone National Park (YNP) and from Obsidian Pool (YNP) and Manitou Springs, Colorado. We have found that Mossbauer spectroscopy can discriminate among the iron-bearing minerals in our samples. Those near the vent and on the surface are identified as ferrihydrite, an amorphous ferric mineraloid. Subsurface samples, collected from cores, which are likely to have undergone inorganic and/or biologically mediated alteration (diagenesis), exhibit spectral signatures that include nontronite (a smectite clay), hematite (alpha-Fe2O3), small-particle/nanophase goethite (alpha-FeOOH), and siderite (FeCO3). We find for iron minerals that Mossbauer spectroscopy is at least as efficient in identification as X-ray diffraction. This observation is important from an exploration standpoint. As a planetary surface instrument, Mossbauer spectroscopy can yield high-quality spectral data without sample preparation (backscatter mode). We have also used field emission scanning electron microscopy (FESEM), in conjunction with energy-dispersive X ray (EDX) fluorescence spectroscopy, to characterize the microbiological component of surface sinters and the relation between the microbiological and the mineralogical framework. Evidence is presented that the minerals found in these deposits can have multi-billion-year residence times and thus may have survived their possible production in a putative early Martian hot spring up to the present day. Examples include the nanophase property and the Mossbauer signature for siderite, which has been identified in a 2.09-billion-year old hematite-rich chert stromatolite. Our research demonstrates that in situ Mossbauer spectroscopy can help determine whether hydrothermal mineral deposits exist on Mars, which is significant for exobiology because of the issue of whether that world ever had conditions conductive to the origin of life. As a useful tool for selection of samples suitable for transport to Earth, Mossbauer spectroscopy will not only serve geological interests but will also have potential for exopaleontology. PMID:11542933

Wade, M L; Agresti, D G; Wdowiak, T J; Armendarez, L P; Farmer, J D

1999-04-25

344

Hydrothermal Venting at Lake Rotomahana, New Zealand, 125 Years After the Tarawera Eruption of 1886  

NASA Astrophysics Data System (ADS)

In early 1886 Lake Rotomahana (North Island, NZ) was a small, shallow lake surrounded on its northern side by a geothermal field that included New Zealand's first major tourist attraction: the beautiful Pink and White (silica sinter) Terraces. The lake dramatically changed on 10 June 1886 when nearby Mt Tarawera erupted. Volcanic and hydrothermal explosions left the landscape scarred with explosion craters, blanketed with ash and mud, and devoid of vegetation. A large, steaming crater replaced the lake and the Pink and White Terraces were apparently destroyed. The crater re-filled during the next 15 years and today Lake Rotomahana is considerably deeper (125 m) and ~5 times larger than pre-eruption. While the evolution of a new geothermal field adjacent to the lake (Waimangu) has been visible and documented over the past 125 years, the evolution of the area perturbed by the eruption then subsequently submerged has been mostly inaccessible. A detailed survey of Lake Rotomahana was conducted in Jan/Feb 2011 to identify the extent and nature of present-day venting. Two autonomous underwater vehicles (AUV) with temperature, pH, turbidity, and oxidation-reduction potential (ORP) sensors completed 18 missions covering a total distance of ~250 km (20-50 m line spacing; 10-15 m altitude). Water samples were collected at 14 CTD stations for chemical analyses. The lake is stratified during summer months with average surface (0-10 m depth) temperatures ~21.5C. The topmost 1-3 meters are 0.5-1C warmer near the boiling springs and geysers that flow into the lake on the western shore. Temperatures decrease from 21.2-16.5C within the thermocline (12-16 m), then to 14.54C at depth (110 m). pH values in the surface layer range from 7.4-7.9, decreasing to 6.50 below ~30 m. Temperature, pH and ORP anomalies in the water column identify at least five areas where warm water is venting into the lake: 1) in the area of the historic Pink Terraces (+3.5C, -0.1 pH, -142 mv); 2) over a bathymetric high near the north shore between the Pink Terraces and "The Pinnacle" (+4C, -0.08 pH, -20 mv); 3) through a broad area south of the 1886 rift, west of Patiti Island (+0.11C, -0.08 pH, -30 mv); 4) near the historic location of the White Terraces (+0.1C, -22 mv above the lakebed, with sediment temperature, inadvertently sampled by the CTD, >18C); and 5) at a bathymetric high near the north shore of the east basin (+0.22C, -0.13 pH, -1 mv). Gas bubbles also stream from the lakebed at most of these locations. Water samples from below the thermocline at locations 4 and 5 above had the highest 3He concentrations measured during this survey. This near-bottom AUV survey has allowed us to map the post-eruption hydrothermal discharge zones in Lake Rotomahana with far greater detail than has previously been possible. The eruption of 1886 altered the geothermal system significantly, resulting in new areas of geothermal activity both within and beyond the lake, although the hot springs that created the famed terraces are still active in approximately the same location as they were prior to the eruption.

Walker, S. L.; de Ronde, C. E.; Fornari, D. J.; Leybourne, M. I.; Ferrini, V.; Kukulya, A.; Littlefield, R.; Scott, B. J.; Immenga, D.; Baker, E. T.

2011-12-01

345

Subseafloor nitrogen transformations in diffuse hydrothermal vent fluids of the Juan de Fuca Ridge evidenced by the isotopic composition of nitrate and ammonium  

NASA Astrophysics Data System (ADS)

Little is known about dissolved inorganic nitrogen (DIN) transformations in hydrothermal vent (HV) fluids. Here, we present the first isotopic measurements of nitrate (?15N and ?18O) and ammonium (?15N) from three HV fields on the Juan de Fuca ridge (NE-Pacific). The dominant process that drives DIN concentration variations in low-T diffuse fluids is water mass mixing below the seafloor, with no effect on the DIN isotope ratios. Strong inter-site variations in the concentration and?15N of NH4+in high-T fluids suggest different subsurface nitrogen (N) sources (deep-sea nitrate versus organic sediments) for hydrothermally discharged ammonium. Low NH4+ community N isotope effects (<3) for net NH4+consumption suggest an important contribution from gross ammonium regeneration in low-T fluids. Elevation of HV nitrate15N/14N and 18O/16O over deep-sea mean isotope values at some sites, concomitant with decreased nitrate concentrations, indicate assimilatory or dissimilatory nitrate consumption by bacteria in the subsurface, with relatively low community N isotope effects (15?k < 3). The low N isotope effects suggest that nitrate assimilation or denitrification occur in bacterial mats, and/or in situ production of low ?15N nitrate. A significantly stronger relative increase for nitrate ?18O than for ?15N was observed at many sites, resulting in marked deviations from the 1:1 relationship for nitrate ?15N versus ?18O that is expected for nitrate reduction in marine settings. Simple box-model calculation show that the observed un-coupling of N and O nitrate isotope ratios is consistent with nitrate regeneration by either nitrite reoxidation and/or partial nitrification of hydrothermal ammonium (possibly originating from N2 fixation). Our isotope data confirm the role of subsurface microbial communities in modulating hydrothermal fluxes to the deep ocean.

Bourbonnais, Annie; Lehmann, Moritz F.; Butterfield, David A.; Juniper, S. Kim

2012-02-01

346

Some features of the trace metal biogeochemistry in the deep-sea hydrothermal vent fields (Menez Gwen, Rainbow, Broken Spur at the MAR and 950?N at the EPR): A synthesis  

NASA Astrophysics Data System (ADS)

Along with summarizing the published literature and our own data some new results on properties of the trace metal biogeochemistry in the deep-sea hydrothermal ecosystems at the Mid-Atlantic Ridge (MAR) and East Pacific Rise (EPR) are shown. Differences in mean concentrations of big group of trace metals (Fe, Mn, Zn, Cu, Ni, Cr, Co, As, Pb, Cd, Ag, Hg) between the biotope water of the low- and high-temperature hydrothermal vent fields were firstly revealed. The same trace metals were studied in different groups of organisms within different temperature zones at one and the same vent field (950?N EPR), as well as in fauna inhabiting geochemically different vent sites. Distribution patterns of Fe, Mn, Zn, Cu, Cd, Pb, Ag, Ni, Cr, Co, As, Se, Sb, and Hg in different taxa gave an evidence of the influence of environmental and biological parameters on their bioaccumulation in organisms. Among the animals a particular champion with respect to the trace metal content was found to be a polychaeta Alvinella pompejana that inhabits the hottest places of the vent sulfide chimneys of the 950?N field, EPR. New data on the trace metal distribution between soft tissues and carbonate shell let us estimate a role of biomineralization in the accumulation of metals in the Bathimodiolus mussels. Contrasting geochemical behavior was revealed for Cu that is enriched in soft tissues of mussels and depleted in shells, on the one hand, and Mn that is accumulated almost totally in mussel shells, on the other hand. Deep-sea hydrothermal biological communities demonstrate a strong concentration function, and bioconcentration factors (BCF) of trace metals estimated for Bathimodiolus mussels collected at the four hydrothermal fields vary within the limits of n102-n105 and are similar to that of the littoral mussels. Due to this and to the high values of biomasses per square meter, the hydrothermal fauna may be considered as a newly discovered biological filter of the oceans.

Demina, Ludmila L.; Holm, Nils G.; Galkin, Sergey V.; Lein, Alla Yu.

2013-10-01

347

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 silk protein which also has a very high thermal conductivity, I combine and extend the mentioned ideas, and propose the general conjecture that several major transitions of evolution were effected by thermal processes, with four additional partial conjectures: (1) The first organisms used heat engines during thermosynthesis in convection cells; (2) The first eukaryotic cells used MT during thermosynthesis in the thermal gradient above SHV; (3) The first metazoans used transport of water or in water during thermosynthesis above SHV under an ice-covered ocean during the Gaskiers Snowball Earth; and (4) The first mammalian brain used a thermal machinery based on thermal gradients in or across the cortex. When experimentally proven these conjectures, which are testable by the methods of synthetic biology, would significantly enhance our understanding of life.

Anthonie W. J. Muller

2012-12-03

348

Defluviimonas indica sp. nov., a marine bacterium isolated from a deep-sea hydrothermal vent environment.  

PubMed

A Gram-stain-negative, strictly aerobic, chemoheterotrophic marine bacterium, designated 20V17(T), was isolated from a deep-sea hydrothermal vent chimney collected from the South-west Indian Ridge. Cells of strain 20V17(T) were motile, short rods, 1.2-1.8 m in length and 0.5-0.7 m in width. Growth was observed at between 20 and 37 C (optimum 25 C-28 C), pH 5.0 and 8.0 (optimum pH 7.0) and 0.5 and 8% (w/v) NaCl (optimum 1.5-2.0% NaCl). The major fatty acids were C(18?:?1)?7c (74.4%), C(19?:?0) cyclo ?8c (11%), C(18?:?0) (5.1%) and C(18?:?0) 3-OH (2.8%), and the polar lipid profile comprised diphosphatidylglycerol, phosphatidylethanolamine, an unidentified glycolipid and four unidentified phospholipids. Ubiquinone 10 was the major quinone. The G+C content of genomic DNA was 66.3 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain 20V17(T) belonged to the genus Defluviimonas and shared 96.5 and 96.1% sequence similarity with Defluviimonas denitrificans D9-3(T) and Defluviimonas aestuarii BS14(T), respectively. On the basis of the taxonomic data obtained in this study, strain 20V17(T) represents a novel species of the genus Defluviimonas, for which the name Defluviimonas indica sp. nov. is proposed. The type strain is 20V17(T) (CGMCC 1.10859(T)?=?JCM 17871(T)?=?MCCC 1A01802(T)). PMID:24670896

Jiang, Lijing; Xu, Hongxiu; Shao, Zongze; Long, Minnan

2014-06-01

349

Vitellibacter nionensis sp. nov., isolated from shallow water hydrothermal vent of Espalamaca, Azores.  

PubMed

A novel, Gram-negative, non-motile, rod-shaped yellow pigmented bacterium, designated VBW088T was isolated from shallow water hydrothermal vent of Espalamaca, Azores. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain VBW088T was clustered with three type strains of Vitellibacter species and exhibited sequence similarity of 97.3 % with Vitellibacter soesokkakensis RSSK-12T. However, strain VBW088T and V. soesokkakensis RSSK-12T showed a low DNA-DNA relatedness (12.73.5 %). Strain VBW088T was positive for catalase and oxidase. Growth occurred at 10-37 C with optimum at 30 C, at pH 6.0-8.0 (optimum 6.0) and with up to 5 % of NaCl concentration (w/v) with optimum at 1-2 % NaCl. The major fatty acids (>10 %) were iso-C15:0 (33.5 %) and iso-C17:0 3-OH (32.0 %). The polar lipids detected in strain VBW088T consisted of phosphatidylethanolamine (PE), one unidentified aminolipid and three unidentified phospholipids. The DNA G+C content of strain VBW088T was 36.7 mol%. On the basis of phylogenetic inference, DNA-DNA relatedness, chemotaxonomic analysis and physiological data, the isolate represents a novel species of the genus Vitellibacter, for which the name Vitellibacter nionensis sp. nov., is proposed, with type strain VBW088T (=KCTC 32420T = MCC 2354T). PMID:25428420

Rajasabapathy, Raju; Mohandass, Chellandi; Yoon, Jung-Hoon; Dastager, Syed Gulam; Liu, Qing; Khieu, Thi-Nhan; Son, Chu Ky; Li, Wen-Jun; Colaco, Ana

2014-11-26

350

Fluid flow rate, temperature and heat flux at Mohns Ridge vent fields: evidence from isosampler measurements for phase separated hydrothermal circulation along the arctic ridge system  

NASA Astrophysics Data System (ADS)

An expedition to the Mohns Ridge in the Norwegian-Greenland sea was carried out in July-August 2005 as part of BIODEEP, lead by University of Bergen (UoB). UoB had previously detected water column methane along this very slow spreading ridge. Previous ROV observations along the ridge (71 deg 18'N, 5 deg 47'W, 605 mbsl) near Jan Mayen had uncovered a broad area of ferric hydroxide-rich bacterial/mineral assemblages, comprising large populations of gallionella bacteria. This area was revisted in 2005. Characteristic of sections of this area ("Gallionella Garden") are chimney-like structures standing ~15 cm tall, often topped by a sea lily (heliometra glacialis). The interior of the structures comprised quasi-concentric bands with vertically-oriented channels. The Oregon State University/Cardiff University Isosampler sensor determined that some of these assemblages support fluid flow through their interior. The outflow from the chimney structures was typically +0.5 deg C, against background temperatures of -0.3 deg C. Flow anomalies were also identified atop extensive bacterial mats. Gallionella Gardens is several km in extent with active, albeit extremely low temperature hydrothermal flow. A field of active high temperature smoker chimney structures was located near Gallionella Garden at 540 mbsl. This field extends ~500 m along a scarp wall, with hydrothermal mounds extending along faults running perpendicular to the scarp, each of which has multiple smoker vents and areas of diffuse flow. There was evidence for phase separation, with a negatively buoyant fluid phase exiting some vent orifices and descending along the vent wall; and evidence for gas phase condensing after leaving some vent orifices. Gas bubble emissions were not uncommon. Isosampler sensors were available that were configured for lower temperature measurements at Gallionella Garden. While capable of detecting variations in effluent at the 4 millidegree level, the temperature ceiling for the sensor tips available aboard ship was 260 deg C (800 deg C-capable isosampler sensors will be available for the 2006 field season). At this depth the phase separation point of seawater is 263 deg C. An isosampler sensor was deployed directly atop an apparently phase-separated white smoker chimney. The sensor indicated 260 deg C before terminating measurement. This was repeated at another vent site, indicating that the fluids were venting at the point of phase separation. Indicated smoker plume flow rates were approximately 1/2 meter per second. A second field "Soria Moria" of high temperature vents was discovered. This field is ~100 m on a side, and is densely populated by active white smoker chimneys, also with evidence for phase-separated flow. These vent fields comprise the first ever arctic vent plume sources ever visited by ROV and measured directly at the source of emission. A return to this area, and exploration and measurement further north is anticipated for 2006. The planned work includes comprehensive Isosampler and bioreactor fluid flow, sampling, geochemical and biogeochemical sampling and incubation.

Schultz, A.; Pedersen, R. B.; Thorseth, I. H.; Taylor, P.; Flynn, M.

2005-12-01

351

The distribution of species and biomass in Riftia pachyptila communities from environmentally different hydrothermal vent habitats at 9\\deg N (East Pacific Rise)  

NASA Astrophysics Data System (ADS)

Hydrothermal vents have been characterized by high biomass, high productivity, high endemicity, and low species diversity. However these ecological characteristics are rarely quantified at an ecosystem level. At 9\\deg N (East Pacific Rise), the giant tubeworm Riftia pachyptila can form dense aggregations in the dynamic mixing zone of hydrothermal vent effluent and deep-ocean bottom water. R. pachyptila must obtain carbon dioxide, hydrogen sulfide, and oxygen in order to support an obligate nutritional symbiosis with chemolithoautotrophic bacteria. In this patchy and ephemeral habitat, the tubes of R. pachyptila provide biogenic substrate that can support high relative abundances of heterotrophic species. As one part of a multidisciplinary collaboration to model the productivity in these habitats, the purpose of this study is to quantify the species composition and the biomass distribution in the R. pachyptila community. Within the scope of this work, a sampling design was employed to concurrently test for spatial and temporal variability in the community structure. Quantitative samples of the R. pachyptila community were collected in consecutive years (2001, 2002) at two environmentally different sites. At one site (Riftia Fields), the mixing zone has relatively low concentrations of hydrogen sulfide, low pH, and high concentrations of iron, whereas the mixing zone at the other site (Tica) has a wider range of hydrogen sulfide concentrations, closer to neutral pH, and undetectable iron concentrations. Analyses of the species composition in eight quantitative samples indicate that there is not a significant difference in species richness and Shannon-Weiner (H') diversity values between sites or years, and that Bray-Curtis community similarity values are very high. When all of the species in a sample are added together, the total abundance and total biomass are much higher in the R. pachyptila community at Tica than at Riftia Fields. The results and of this project will be integrated with species-specific respiration rates and in situ environmental measurements to generate an ecosystem-level model of the net primary productivity.

Govenar, B.; Aperghis, A.; Glanville, J.; Le Bris, N.; Fisher, C. R.

2003-12-01

352

Fossilization of Iron-Oxidizing Bacteria at Hydrothermal Vents: a Useful Biosignature on Mars?  

NASA Astrophysics Data System (ADS)

Iron oxidizing bacteria are ubiquitous in marine and terrestrial environments on Earth, where they often display distinctive cell morphologies and are commonly encrusted by minerals, especially bacteriogenic iron oxides and silica. Putative microfossils of iron oxidizing bacteria have been found in jaspers as old as 490Ma and microbial iron oxidation may be an ancient metabolic pathway. In order to investigate the usefulness of mineralized iron oxidizing bacteria as a biosignature, we have examined mineral samples collected from relict hydrothermal systems along Explorer Ridge, NE Pacific Ocean. In addition, microaerophilic, neutrophilic iron oxidizing bacteria, isolated from Pacific hydrothermal vents, were grown in a Fe-enriched seawater medium at constant pH (6.5) and oxygen concentration (5 percent) in a controlled bioreactor system. Both natural samples and experimental products were examined with a combination of variable pressure scanning electron microscopy (SEM), field emission gun SEM, and in some cases by preparing samples with a focused ion beam (FIB) milling system. Natural seafloor samples display abundant filamentous forms often resembling, in both size and shape, the twisted stalks of Gallionella and the elongated filaments of Leptothrix. Generally, these filamentous features are 1-5 microns in diameter and up to several microns in length. Some samples consist entirely of low- density, porous masses of silica encrusted filamentous forms. Presumably, these masses were formed by a rapid precipitation by the influx of silica-rich fluids into a microbial mat dominated by bacteria with filamentous morphologies. The presence of rare, amorphous (unmineralized) filamentous matter rich in C and Fe suggests that these bacteria were iron oxidizers. There is no evidence that sulfur oxidizers were present. Filamentous features sectioned by FIB milling show internal material within semi-hollow tubular-like features. Silica encrustations also show pseudo-concentric growth bands. In the bioreactor cultures, constant conditions led to abundant microbial growth and formation of an iron oxyhydroxide precipitate, either in direct association with the cells or within the growth medium. This suggests that not all of the iron precipitation is biogenic in origin. Cells typically show a filamentous morphology reminiscent of the mineral-encrusted forms observed in the natural samples. Continuing work includes high-resolution TEM observations of cultured organisms, examination of 2-year long in situ seafloor incubation experiments, and bioreactor silicification experiments in order to better understand the roles of iron and silica in the fossilization process. Microaerophilic iron oxidation could have existed on the early Earth in environments containing small amounts of oxygen produced either by locally concentrated photosynthetic microorganisms (e.g., cyanobacteria) or abiotically, as proposed for the subsurface of the Fe-dominated Rio Tinto (Spain) basin system. By analogy, similar subsurface or near-surface microaerophilic environments could have existed on Mars in the past. The distinctive morphologies and mineralization patterns of iron oxidizing bacteria could be a useful biosignature to search for on Mars. Deposits and biogenic features similar to those described here could theoretically be identified on Mars with existing imaging and analytical technologies. Therefore, future missions to Mars should target ancient hydrothermal systems, some of which have been putatively identified already.

Leveille, R. J.; Lui, S.

2009-05-01

353

Thermococcus Thioreducens sp. nov., A Novel Hyperthermophilic, Obligately Sulfur-Reducing Archaeon from a Deep-Sea Hydrothermal Vent  

NASA Technical Reports Server (NTRS)

A novel hyperthermophilic organo-heterotrophic archaeon, strain OGL-20P(sup T), was isolated from 'black smoker' chimney material from the Rainbow hydrothermal vent site on the Mid-Atlantic Ridge (36.2 N; 33.9 W). The cells of strain OGL-20P(sup T) have an irregular coccoid shape and are motile with a single flagellum. Growth was observed to occur within the pH range 5.0-8.5 (optimum pH 7.0), NaCl concentration range 1-5 % (w/v) (optimum 3 %), and temperature range 55-94 C (optimum 83-85 C). Novel isolate is strictly anaerobic and obligately dependent from elemental sulfur as electron acceptor, but it cannot reduce sulfate, sulfite, thiosulfate, iron (III) or nitrate. Proteolysis products that can be utilized as substrates during sulfur-reduction are: peptone, bactotryptone, casamino-acids, and yeast extract. Strain OGL-20P(sup T) is resistant to ampicillin, chloramphenicol, kanamycin, and gentamycin, but sensitive to tetracycline and rifampicin. The G+C content of DNA is 57.1 mol% . Comparative 16S rRNA gene sequence analysis revealed that strain OGL-20P(sup T) is most closely related to Thermococcus celer and 'T. barossii', but no significant homology by DNA-DNA hybridization was observed between those species and the new isolate. On the basis of physiological and molecular properties of the new isolate, the name Thermococcus thioreducens sp. nov., is proposed. The type strain is OGL-20P(sup T) (= ATCC BAA-394(sup T) = DSM 1498(sup T)).

Pikuta, Elena V.; Hoover, Richard B.; Marsic, Damien; Bej, Asim K.; Garriott, Owen

2003-01-01

354

Thermococcus sulfurophilus sp. nov., a New Hyperthermophilic, Sulfur-Reducing Archaeon Isolated from Deep-Sea Hydrothermal Vent  

NASA Technical Reports Server (NTRS)

A new hyperthermophilic, anaerobic, sulfur-reducing, organo-heterotrophic archaeon, strain OGL-20P, was isolated from "black smoker" chimney material at the Rainbow hydrothermal vent site in the Atlantic Ocean (36.2 N; 33.9 W). The cells of strain OGL-20P have irregular coccoid shape and are motile with a single flagellum. Growth occurs within pH range of 5.5-8.2 (optimal at pH 7.0-7.2), salinity range of 1-5% NaCl (optimal concentration 3% NaCl wt/vol), and temperature range of +55 C to +94 C (optimal growth at +83 C to +85 C). Strain OGL-20P is resistant to freezing (at -20 C). New isolate is strictly anaerobic with sulfur-type of respiration. A limited number of compounds are utilized as electron donors, including peptone, becto-tryptone, casamino-acids, and yeast extract but does not grow with separate amino acids. Sulfur and Iron can be used as electron acceptors; but not sulfate, sulfite, thiosulfate or nitrate. Strain OGL-20P is resistant to chloramphenicol, kanamycin, and gentamycin. Growth of str. OGL20P is inhibited by tetracyclin but not by Na2MoO4. The G+C content of DNA is 57.2 mol%. The 16S ribosomal RNA sequence analysis allows one to classify strain OGL-20P as a representative of a now species of Thermococcus genus. The name Thermococcus sulfurophilus op. nov., was suggested for the new isolate, type strain OGL-20P (sup T) (= ATCC BAA_394 (sup T) = DSM...(supT)).

Pikuta, Elena V.; Hoover, Richard B.; Whitman, William B.; Marsic, Damien; Garriott, Owen; Six, N. Frank (Technical Monitor)

2002-01-01

355

Zeta-Proteobacteria dominate the formation of microbial mats in low-temperature hydrothermal vents at Loihi Seamount  

NASA Astrophysics Data System (ADS)

Loihi Seamount is Hawaii's youngest volcano and one of the earth's most active. Loihi is located 30 km SE of the big island of Hawaii and rises over 3000m above the sea floor and summits at 1100m below sea level. An eruption in 1996 of Loihi led to the formation of Pele's Pit, a 300 meter deep caldera. The current observations have revealed diffuse hydrothermal venting causing low to intermediate temperatures (10 to 65C). The elevated temperatures, coupled with high concentrations of Fe(II) (ranging from 50 to 750 ?M) support conditions allowing for extensive microbial mat formation. The focus of this study was to identify the colonizing populations of bacteria generated by the microbial mats at Loihi Seamount. Twenty-six microbial growth chambers were deployed and recovered after placement in the flow of hydrothermal vents for 3 to 8 days from within Loihi's caldera. Genomic DNA was extracted from samples and analyzed by Terminal-Restriction Fragment Length Polymorphism (T-RFLP) using eight restriction enzyme treatments to generate fingerprints from bacterial amplicons of small subunit rRNA genes (SSU rDNAs). Pearson product-moment coupled with UPGMA cluster analysis of these T-RFLP fingerprints showed that these communities bifurcated into two primary clusters. The first (Group 1) had an average vent effluent temperature of 44C, and the second (Group 2) had an average vent effluent temperature of 64C. Representative samples from within the two clusters (or groups) were chosen for further clone library and sequencing analysis. These libraries revealing a dominance of the recently discovered zeta- Proteobacteria in the lower temperature group (Group 1) indicating that they were the dominant colonizers of the microbial mats. These microaerophilic, obligately lithotrophic, Fe-oxidizing bacteria are most closely related to Mariprofundus ferrooxydans. The higher temperature group (Group 2) was dominated by epsilon- Proteobacteria primarily of the genus Sulfurimonas, which are sulfur- and thiosulfate-oxidizing bacteria.

Rassa, A. C.; McAllister, S. M.; Safran, S. A.; Moyer, C. L.

2007-12-01

356

Thermococcus peptonophilus sp. nov., a fast-growing, extremely thermophilic archaebacterium isolated from deep-sea hydrothermal vents  

Microsoft Academic Search

Two extremely thermophilic archaebacteria, strains OG-1 and SM-2, were isolated from newly discovered deep-sea hydrothermal\\u000a vent areas in the western Pacific ocean. These strains were cocci, obligately anaerobic Archaea about 0.72 ?m in diameter.\\u000a Optimum growth conditions for OG-1 and SM-2 were at 8590?C (range 60100?C), pH 6 (range pH 48), a NaCl concentration of\\u000a 3% (range 15%), and a

Juan M. Gonzlez; Chiaki Kato; Koki Horikoshi

1995-01-01

357

Evidence of Chemolithoautotrophy in the Bacterial Community Associated with Alvinella pompejana, a Hydrothermal Vent Polychaete  

PubMed Central

The deep-sea polychaete Alvinella pompejana colonizes tubes on the sides of black smoker chimneys along the East Pacific Rise. A diverse, yet phylogenetically constrained episymbiotic community is obligately associated with its dorsal surface. The morphologically and phylogenetically distinct dominant episymbionts have not yet been cultured, and there are no clearly defined roles for these bacteria in this symbiosis. A large insert fosmid library was screened for the presence of the two dominant phylotypes. Two fosmids, 35.2 and 38 kb, containing phylotype-specific 16S ribosmal DNA sequences were fully sequenced. Each fosmid had a gene encoding ATP citrate lyase, a key enzyme in the reverse tricarboxylic acid (rTCA) cycle, a CO2 fixation pathway. A selection of episymbiont communities from various geographic locations and vent sites were screened for the presence, diversity, and expression (via reverse transcription-PCR) of the ATP citrate lyase gene. Our results indicate that the ATP citrate lyase gene is not only a consistent presence in these episymbiont communities but is also expressed. Phylogenetically distinct forms of ATP citrate lyase were also found associated with and expressed by bacteria extracted from the tubes of A. pompejana. Utilizing PCR with degenerate primers based on a second key enzyme in the rTCA cycle, 2-oxoglutarate:acceptor oxidoreductase, we also demonstrated the persistent presence and expression of this gene in the episymbiont community. Our results suggest that members of both the episymbiont and the surrounding free-living communities display a chemolithoautotrophic form of growth and therefore contribute fixed carbon to other organisms in the vent community. PMID:12957888

Campbell, Barbara J.; Stein, Jeffrey L.; Cary, S. Craig

2003-01-01

358

Integrated Fe- and S-isotope study of seafloor hydrothermal vents at East Pacific Rise 9-10N  

USGS Publications Warehouse

In this study, we report on coupled Fe- and S-isotope systematics of hydrothermal fluids and sulfide deposits from the East Pacific Rise at 910N to better constrain processes affecting Fe-isotope fractionation in hydrothermal environments. We aim to address three fundamental questions: (1) Is there significant Fe-isotope fractionation during sulfide precipitation? (2) Is there significant variability of Fe-isotope composition of the hydrothermal fluids reflecting sulfide precipitation in subsurface environments? (3) Are there any systematics between Fe- and S-isotopes in sulfide minerals? The results show that chalcopyrite, precipitating in the interior wall of a hydrothermal chimney displays a limited range of ?56Fe values and ?34S values, between ? 0.11 to ? 0.33 and 2.2 to 2.6 respectively. The ?56Fe values are, on average, slightly higher by 0.14 relative to coeval vent fluid composition while ?34S values suggest significant S-isotope fractionation (? 0.6 0.2) during chalcopyrite precipitation. In contrast, systematically lower ?56Fe and ?34S values relative to hydrothermal fluids, by up to 0.91 and 2.0 respectively, are observed in pyrite and marcasite precipitating in the interior of active chimneys. These results suggest isotope disequilibrium in both Fe- and S-isotopes due to S-isotopic exchange between hydrothermal H2S and seawater SO42? followed by rapid formation of pyrite from FeS precursors, thus preserving the effects of a strong kinetic Fe-isotope fractionation during FeS precipitation. In contrast, ?56Fe and ?34S values of pyrite from inactive massive sulfides, which show evidence of extensive late-stage reworking, are essentially similar to the hydrothermal fluids. Multiple stages of remineralization of ancient chimney deposits at the seafloor appear to produce minimal Fe-isotope fractionation. Similar affects are indicated during subsurface sulfide precipitation as demonstrated by the lack of systematic differences between ?56Fe values in both high-temperature, Fe-rich black smokers and lower-temperature, Fe-depleted vents.

Rouxel, O.; Shanks, W. C., III; Bach, W.; Edwards, K.J.

2008-01-01

359

Field distribution and sulphide tolerance of Capitella capitata (Annelida: Polychaeta) around shallow water hydrothermal vents off Milos (Aegean Sea). A new sibling species?  

Microsoft Academic Search

The cosmopolitan polychaete Capitella capitata, known as a complex of opportunistic sibling species, usually dominates the macrobenthos of polluted or unpredictable environments.\\u000a A population of C. capitata, termed Capitella sp. M, was found in a shallow water hydrothermal vent area south of Milos (Greece). Here, this population occurs close to\\u000a vent outlets (termed the transition zone), an environment with steep

I. Gamenick; M. Abbiati; O. Giere

1998-01-01

360

Identifying Martian Hydrothermal Sites: Geological Investigation Utilizing Multiple Datasets  

NASA Technical Reports Server (NTRS)

Comprehensive geological investigations of martian landscapes that may have been modified by magmatic-driven hydrothermal activity, utilizing multiple datasets, will yield prime target sites for future hydrological, mineralogical, and biological investigations.

Dohm, J. M.; Baker, V. R.; Anderson, R. C.; Scott, D. H.; Rice, J. W., Jr.; Hare, T. M.

2000-01-01

361

Dual symbiosis with co-occurring sulfur-oxidizing symbionts in vestimentiferan tubeworms from a Mediterranean hydrothermal vent.  

PubMed

Vestimentiferan Tws colonize hydrothermal vents and cold seeps worldwide. They lack a digestive system and gain nutrition from endosymbiotic sulfur-oxidizing bacteria. It is currently assumed that vestimentiferan Tws harbour only a single endosymbiont type. A few studies found indications for additional symbionts, but conclusive evidence for a multiple symbiosis is still missing. We investigated Tws from Marsili Seamount, a hydrothermal vent in the Mediterranean Sea. Molecular and morphological analyses identified the Tws as Lamellibrachia anaximandri. 16S ribosomal RNA clone libraries revealed two distinct gammaproteobacterial phylotypes that were closely related to sequences from other Lamellibrachia symbionts. Catalysed reporter deposition fluorescence in situ hybridization with specific probes showed that these sequences are from two distinct symbionts. We also found two variants of key genes for sulfur oxidation and carbon fixation, suggesting that both symbiont types are autotrophic sulfur oxidizers. Our results therefore show that vestimentiferans can host multiple co-occurring symbiont types. Statistical analyses of vestimentiferan symbiont diversity revealed that host genus, habitat type, water depth and geographic region together accounted for 27% of genetic diversity, but only water depth had a significant effect on its own. Phylogenetic analyses showed a clear grouping of sequences according to depth, thus confirming the important role water depth played in shaping vestimentiferan symbiont diversity. PMID:24552661

Zimmermann, Judith; Lott, Christian; Weber, Miriam; Ramette, Alban; Bright, Monika; Dubilier, Nicole; Petersen, Jillian M

2014-12-01

362

Martian Magmatic-Driven Hydrothermal Sites: Potential Sources of Energy, Water, and Life  

NASA Technical Reports Server (NTRS)

Magmatic-driven processes and impact events dominate the geologic record of Mars. Such recorded geologic activity coupled with significant evidence of past and present-day water/ice, above and below the martian surface, indicate that hydrothermal environments certainly existed in the past and may exist today. The identification of such environments, especially long-lived magmatic-driven hydrothermal environments, provides NASA with significant target sites for future sample return missions, since they (1) could favor the development and sustenance of life, (2) may comprise a large variety of exotic mineral assemblages, and (3) could potentially contain water/ice reservoirs for future Mars-related human activities. If life developed on Mars, the fossil record would presumably be at its greatest concentration and diversity in environments where long-term energy sources and water coexisted such as at sites where long-lived, magmatic-driven hydrothermal activity occurred. These assertions are supported by terrestrial analogs. Small, single-celled creatures (prokaryotes) are vitally important in the evolution of the Earth; these prokaryotes are environmentally tough and tolerant of environmental extremes of pH, temperature, salinity, and anoxic conditions found around hydrothermal vents. In addition, there is a great ability for bacteria to survive long periods of geologic time in extreme conditions, including high temperature hydrogen sulfide and sulfur erupted from Mount St. Helens volcano. Our team of investigators is conducting a geological investigation using multiple mission-derived datasets (e.g., existing geologic map data, MOC imagery, MOLA, TES image data, geophysical data, etc.) to identify prime target sites of hydrothermal activity for future hydrological, mineralogical, and biological investigations. The identification of these sites will enhance the probability of success for future missions to Mars.

Anderson, R. C.; Dohm, J. M.; Baker, V. R.; Ferris, J. C.; Hare, T. M.; Tanaka, K. L.; Klemaszewski, J. E.; Skinner, J. A.; Scott, D. H.

2000-01-01

363

Modeling the hydrothermal circulation and the hydrogen production at the Rainbow site with Cast3M  

NASA Astrophysics Data System (ADS)

On the Mid-Atlantic Ridge, the Rainbow venting site is described as an ultramafic-hosted active hydrothermal site and releases high fluxes of methane and hydrogen [1, 2]. This behavior has first been interpreted as the result of serpentinization processes. But geochemical reactions involving olivine and plagioclase assemblages, and leading to chlorite, tremolite, talc and magnetite assemblages, could contribute to the observed characteristics of the exiting fluid [2]. The predominance of one of these geochemical reactions or their coexistence strongly depend on the hydrothermal fluid circulation. We developed and validated a 2D/3D numerical model using a Finite Volume method to simulate heat driven fluid flows in the framework of the Cast3M code [3, 4]. We also developed a numerical model for hydrogen production and transport that is based on experimental studies of the serpentinization processes [5-6]. This geochemical model takes into account the exothermic and water-consuming behavior of the serpentinization reaction and it can be coupled to our thermo-hydrogeological model. Our simulations provide temperatures, mass fluxes and venting surface areas very close to those estimated in-situ [7]. We showed that a single-path model [8] was necessary to simulate high values such as the in-situ measured temperatures and estimated water mass fluxes of the Rainbow site [7]. This single-path model will be used to model the production and transport of hydrogen at the Rainbow hydrothermal site. References [1]Charlou et al. (2010) AGU Monograph series. [2]Seyfried et al. (2011) Geochim. Cosmochim. Acta 75, 1574-1593. [3]http://www-cast3m.cea.fr. [4]Martin & Fyfe (1970) Chem. Geol. 6, 185-202. [5] Marcaillou et al. (2011) Earth and Planet. Sci. Lett. 303, 281-290. [6]Malvoisin et al. (2012) JGR, 117, B01104. [7]Perez et al. (2012) submited to Computational Geosciences. [8]Lowell & Germanovich (2004) AGU, Washington DC, USA.

Perez, F.; Mgler, C.; Charlou, J.; Jean-baptiste, P.

2012-12-01

364

Spatial Variation in the Population Structure and Reproductive Biology of Rimicaris hybisae (Caridea: Alvinocarididae) at Hydrothermal Vents on the Mid-Cayman Spreading Centre  

PubMed Central

The dynamics and microdistribution of faunal assemblages at hydrothermal vents often reflect the fine-scale spatial and temporal heterogeneity of the vent environment. This study examined the reproductive development and population structure of the caridean shrimp Rimicaris hybisae at the Beebe and Von Damm Vent Fields (Mid-Cayman Spreading Centre, Caribbean) using spatially discrete samples collected in January 2012. Rimicaris hybisae is gonochoric and exhibits iteroparous reproduction. Oocyte size-frequency distributions (21-823 m feret diameters) varied significantly among samples. Embryo development was asynchronous among females, which may result in asynchronous larval release for the populations. Specimens of R. hybisae from the Von Damm Vent Field (2294 m) were significantly larger than specimens from the Beebe Vent Field. Brooding females at Von Damm exhibited greater size-specific fecundity, possibly as a consequence of a non-linear relationship between fecundity and body size that was consistent across both vent fields. Samples collected from several locations at the Beebe Vent Field (49444972 m) revealed spatial variability in the sex ratios, population structure, size, and development of oocytes and embryos of this mobile species. Samples from the Von Damm Vent Field and sample J2-613-24 from Beebe Woods exhibited the highest frequencies of ovigerous females and significantly female-biased sex ratios. Environmental variables within shrimp aggregations may influence the distribution of ovigerous females, resulting in a spatially heterogeneous pattern of reproductive development in R. hybisae, as found in other vent taxa. PMID:23555955

Nye, Verity; Copley, Jonathan T.; Tyler, Paul A.

2013-01-01

365

CAREER: Hydrothermal vent flow and temperature fluctuations: exploring long-term variability through an integrated research and education program  

NASA Astrophysics Data System (ADS)

An acoustic scintillation system was built in partnership with ASL Environmental Sciences (Sidney BC Canada), which provided a unique opportunity for two engineering undergraduate students to live and work abroad. The acoustic instrumentation was tested in coastal waters and then deployed to study deep-sea hydrothermal plume dynamics. Undergraduate students were involved in the deployment of instrumentation and the development of processing software to give vertical velocities and temperature fluctuations from a vigorous hydrothermal vent. A graduate student thesis has yielded insights into the vertical and azimuthal dependence of entrainment and into plume bending and rise height. Teachers and Ocean Science Bowl students also participated in research cruises describing physical oceanography of estuaries, coastal waters, and deep-sea hydrothermal vents and participated in data collection, processing and analysis. Teachers used the knowledge they gained to develop creative educational curricula at their schools, to present their experiences at national conferences and to publish an article in the National Science Teachers Association - The Science Journal. One of the teachers was recently recognized with the Presidential Award for Excellence in Mathematics and Science Teaching. Working with the ocean bowl team at Oconee County High School has led to top ten placements in the national championships in 2005 (fourth place) and 2006 (sixth place). In order to increase quantitative methods in an undergraduate class, students acquire data from an ocean observatory and analyze the data for specific quantities of interest. One such project led to the calculation of the upper ocean heat content for the Greenland Sea using 7 years of Argo profiles, which showed a 0.04oC/year trend. These results were then published in JGR.

Di Iorio, D.

2011-12-01

366

Free-living bacterial communities associated with tubeworm (Ridgeia piscesae) aggregations in contrasting diffuse flow hydrothermal vent habitats at the Main Endeavour Field, Juan de Fuca Ridge  

PubMed Central

We systematically studied free-living bacterial diversity within aggregations of the vestimentiferan tubeworm Ridgeia piscesae sampled from two contrasting flow regimes (High Flow and Low Flow) in the Endeavour Hydrothermal Vents Marine Protected Area (MPA) on the Juan de Fuca Ridge (Northeast Pacific). Eight samples of particulate detritus were recovered from paired tubeworm grabs from four vent sites. Most sequences (454 tag and Sanger methods) were affiliated to the Epsilonproteobacteria, and the sulfur-oxidizing genus Sulfurovum was dominant in all samples. Gammaproteobacteria were also detected, mainly in Low Flow sequence libraries, and were affiliated with known methanotrophs and decomposers. The cooccurrence of sulfur reducers from the Deltaproteobacteria and the Epsilonproteobacteria suggests internal sulfur cycling within these habitats. Other phyla detected included Bacteroidetes, Actinobacteria, Chloroflexi, Firmicutes, Planctomycetes, Verrucomicrobia, and DeinococcusThermus. Statistically significant relationships between sequence library composition and habitat type suggest a predictable pattern for High Flow and Low Flow environments. Most sequences significantly more represented in High Flow libraries were related to sulfur and hydrogen oxidizers, while mainly heterotrophic groups were more represented in Low Flow libraries. Differences in temperature, available energy for metabolism, and stability between High Flow and Low Flow habitats potentially explain their distinct bacterial communities. PMID:23401293

Forget, Nathalie L; Kim Juniper, S

2013-01-01

367

Hydrothermal methane venting between 12N and 26N along the Mid-Atlantic Ridge  

Microsoft Academic Search

Hydrographic surveys along the Mid-Atlantic Ridge (MAR) between 12N and 26N, carried out from 1984 to 1990, show a variable pattern of CH4-rich water column plumes. The vertical distribution of CH4 at stations located every 20-40 km is presented along this 1200-km-long section of the MAR. CH4 venting is clearly demonstrated. CH4-enriched fluids rise from vents as plumes; spreading is

Jean-Luc Charlou; Jean-Pierre Donval

1993-01-01

368

Getting the bigger picture: Using precision Remotely Operated Vehicle (ROV) videography to acquire high-definition mosaic images of newly discovered hydrothermal vents in the Southern Ocean  

NASA Astrophysics Data System (ADS)

Direct visual observations from submersible vehicles at hydrothermal vents typically only reveal a fraction of the vent environment at any one time. We describe the use of precision Remotely Operated Vehicle (ROV) videography to produce extensive mosaic images of hydrothermal vent chimneys and surrounding seafloor areas (c. 250 m2), with sufficient resolution to determine distributions of macro- and megafauna. Doppler velocity log navigation (DVLNAV) was used to follow overlapping vertical survey lines in a fixed plane facing a vent chimney, while acquiring high-definition video imagery using a forward-looking camera. The DVLNAV also enabled the vehicle to follow overlapping horizontal survey lines while acquiring seafloor imagery from a downward-looking video camera and mapping variations in seawater temperature. Digital stills images extracted from video were used to compile high-resolution composite views of the surveyed areas. Applying these image acquisition techniques at vent fields on the East Scotia Ridge, Southern Ocean, revealed consistent patterns of faunal zonation around vent sources, variations in proportions of faunal assemblage types on different faces of a vent chimney, and differences in proportions of faunal assemblages between two different vent fields. The technique can therefore be used to determine the composition and spatial distribution of fauna across complex areas of topography, such as vent fields, where mosaic images of vertical structures cannot currently be acquired using other platforms such as autonomous underwater vehicles (AUVs). These image acquisition techniques, demonstrated here in the first ROV dives at newly discovered vent fields, may offer an appropriate technology for rapid baseline studies required by the potential mining of seafloor massive sulfides (SMS).

Marsh, Leigh; Copley, Jonathan T.; Huvenne, Veerle A. I.; Tyler, Paul A.; Isis ROV Facility

2013-08-01

369

Distribution, activity and function of short-chain alkane degrading phylotypes in hydrothermal vent sediments  

NASA Astrophysics Data System (ADS)

Global geochemical analyses suggest that C2-C4 short chain alkanes are a common component of the utilizable carbon pool in deep-sea sediments worldwide and have been found in diverse ecosystems. From a thermodynamic standpoint, the anaerobic microbial oxidation of these aliphatic hydrocarbons is more energetically yielding than the anaerobic oxidation of methane (AOM). Therefore, the preferential degradation of these hydrocarbons may compete with AOM for the use of oxidants such as sulfate, or other potential oxidants. Such processes could influence the fate of methane in the deep-sea. Sulfate-reducing bacteria (SRB) from hydrocarbon seep sediments of the Gulf of Mexico and Guaymas Basin have previously been enriched that anaerobically oxidize short chain alkanes to generate CO2 with the preferential utilization of 12C-enriched alkanes (Kniemeyer et al. 2007). Different temperature regimens along with multiple substrates were tested and a pure culture (deemed BuS5) was isolated from mesophilic enrichments with propane or n-butane as the sole carbon source. Through comparative sequence analysis, strain BuS5 was determined to cluster with the metabolically diverse Desulfosarcina / Desulfococcus cluster, which also contains the SRB found in consortia with anaerobic, methane-oxidizing archaea in seep sediments. Enrichments from a terrestrial, low temperature sulfidic hydrocarbon seep also corroborated that propane degradation occurred with most bacterial phylotypes surveyed belonging to the Deltaproteobacteria, particularly Desulfobacteraceae (Savage et al. 2011). To date, no microbes capable of ethane oxidation or anaerobic C2-C4 alkane oxidation at thermophilic temperature have been isolated. The sediment-covered, hydrothermal vent systems found at Middle Valley (Juan de Fuca Ridge, eastern Pacific Ocean) are a prime environment for investigating mesophilic to thermophilic anaerobic oxidation of short-chain alkanes, given the elevated temperatures and dissolved hydrocarbon species characteristic of these metalliferous sediments. These systems are also characterized by sharp physicochemical gradients that have been shown to have a pronounced effect on microbial ecology and activity. Sediments were collected from a Middle Valley field with relatively high concentrations of short-chain alkanes and incubated in anaerobic batch reactors with each individual alkane (C1, C2, C3 and C4, respectively) at a range of temperatures (25, 55 and 75 C) to mimic environmental physico-chemical conditions in a closed system. Stable carbon isotope ratios and radiotracer incubations provide clear evidence for C2-C4 alkane oxidation in the sediments over time. Upon identifying sediments with anaerobic alkane oxidation activity, microbial communities were screened via 16S rRNA pyrosequencing, and key phylotypes were then quantified using both molecular and microscopic methods. There were shifts in overall community composition and putative alkane-oxidizing phylotypes after the incubation period with the alkane substrates. These are the first evidence to date indicating that anaerobic C2-C4 alkane oxidation occurs across a broad range of temperatures in metalliferous sediments.

Adams, M. M.; Joye, S. B.; Hoarfrost, A.; Girguis, P. R.

2012-12-01

370

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

Microsoft Academic Search

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

B. J. Murton; D. P. Connelly; J. T. Copley; K. L. Stansfield; P. A. Tyler

2010-01-01

371

Beryllium 10 in hydrothermal vent deposits from the East Pacific Ridges: Role of sediments in the hydrothermal processes  

NASA Astrophysics Data System (ADS)

Beryllium 10 concentrations were determined for 31 handpicked hydrothermal sulfides, six oxyhydroxides, seven basalts, and five sediments collected from the hydrothermally active areas of the East Pacific ridges. The samples include specimens from the East Pacific Rise (EPR) at 21N and 13N, the Galapagos Rift, the Guaymas Basin, and the Gorda and the Juan de Fuca ridges. Additional samples from massive sulfides associated with the Oman ophiolites were studied. In all samples, we obtained values ranging from 0.04 106 atoms/g to 125 106 atoms/g, with the lowest values being very close to our blank (0.015 106 atoms/g). The data show systematic variations with sample location and type. The 10Be concentrations measured for the mid-ocean basalts are of the order of 0.3 10 atoms/g and reach 3800 106 atoms/g for the pelagic deep-sea sediments collected near the EPR 21N. Based on their 10Be concentrations, we can clearly distinguish two categories of sulfides: sulfides containing low 10Be concentration (<106 atoms/g) sitting directly on the mid-ocean basalt (EPR or Juan de Fuca), and sulfides with high 10Be concentration (>106 atoms/g) located atop of a thick pile of young sediments (Guaymas Basin or Gorda Ridge). The oxy-hydroxides, collected on some of the Juan de Fuca chimneys, are always very rich in 10Be with concentrations reaching 125 106 atoms/g. We propose three mechanisms to explain these data: (1) mechanical entrapment of sediments in the hydrothermal chimneys as observed in the Gorda Ridge sulfides, (2) leaching of 10Be from the ocean crust sediments, transport by hydrothermal fluids, and coprecipitation with heavy metals as hypothesized to explain the Be concentrations observed in the Guaymas Basin, and (3) passive adsorption of 10Be from seawater, preferred hypothesis oxy-hydroxides of the areas with no sediment cover.

Vallet-Silver, J. N.; Tera, F.; Klein, J.; Middleton, R.

1987-10-01

372

Thermococcus fumicolans sp. nov., a New Hyperthermophilic Archaeon Isolated from a Deep-sea Hydrothermal Vent in the North Fiji Basin  

Microsoft Academic Search

An extremely thermophilic archaeon, strain ST557T (T = type strain), was isolated from a deep-sea hydrothermal vent in the North Fiji Basin. This strain is a strictly anaerobic coccus whose cells are about 0.8 to 2 pm in diameter. The optimum temperature, pH and sea salt concentration for growth are 85\\

ANNE GODFROY; JEAN GUEZENNEC; FRANCOISE LESONGEUR; GERARD RAGUENES; ALAIN RIMBAULT

373

Effect of cadmium, copper and mercury on antioxidant enzyme activities and lipid peroxidation in the gills of the hydrothermal vent mussel Bathymodiolus azoricus  

Microsoft Academic Search

Metals are known to influence lipid peroxidation and oxidative status of marine organisms. Hydrothermal vent mussels Bathymodiolus azoricus live in deep-sea environments with anomalous conditions, including high metal concentrations. Although B. azoricus are aerobic organisms they possess abundant methano and thioautotrophic symbiotic bacteria in the gills. The enzymatic defences (superoxide dismutase (SOD), catalase (CAT), total glutathione peroxidase (Total GPx) and

A. Serafim; M. J. Bebianno; R. Cosson; B. Shillito; A. Fiala-Mdioni

2004-01-01

374

Draft Genome Sequence of Defluviimonas indica Strain 20V17T, Isolated from a Deep-Sea Hydrothermal Vent Environment in the Southwest Indian Ocean  

PubMed Central

Here, we present the draft genome sequence of Defluviimonas indica 20V17T, which was isolated from a deep-sea hydrothermal vent chimney sample in the southwest Indian Ocean. The draft genome sequence contains 4,268,338bp, with a G+C content of 66.33%. PMID:24903865

Jiang, Lijing; Long, Minnan

2014-01-01

375

Morphology of cone-fields in SW Elysium Planitia - Traces of hydrothermal venting on Mars?  

NASA Astrophysics Data System (ADS)

Introduction Small cone-shaped features with summit pits can be found in several regions on Mars; mainly in Isidis Planitia; Elysium Planitia; Amazonis Planitia; Acidalia Planitia; in the Cydonia Region; in Cerberus Planum; the Phlegra Montes and on several volcanic flanks. They vary greatly in size and morphology and have been compared to terrestrial features of various origins; namely (1) cinder cones (e.g. [1]), (2) tuff cones or tuff rings (e.g. [2]), (3) rootless cones (pseudocraters) (e.g. [3], [4]), (4) pingos (e.g. [5], [6]) and (5) mud volcanoes (e.g. [7]). They are often found near volcanic centers and large lava fields or cluster in regions where the volatile content of the Martian regolith was/is supposedly high. This has led to the assumption that (ground-) water or ground ice was a trigger or driving force of cone formation. They could therefore, be an important indicator of the history of water on the planet. We have studied an area in western Elysium Planitia, bordering the Aeolis Planum plateau, which exhibits a large number of pitted cones, ridges and dome-like structures. Their distribution and morphology differs strongly from pitted cones elsewhere in Elysium Planitia, which have mainly been interpreted as hydrovolcanic rootless cones, and from other regions on Mars. Based on our observations, we present an alternative model for cone formation in the study