Deep-sea Hydrothermal Vent Ecosystems Research Articles

Genome sequence of a novel deep-sea vent epsilonproteobacterial phage provides new insight into the co-evolution of Epsilonproteobacteria and their phages

Epsilonproteobacteria are among the predominant primary producers in deep-sea hydrothermal vent ecosystems. However, phages infecting deep-sea vent Epsilonproteobacteria have never been isolated and characterized. Here, we successfully isolated a novel temperate phage, NrS-1, that infected a deep-sea vent chemolithoautotrophic isolate of Epsilonproteobacteria, Nitratiruptor sp. SB155-2, and its entire genome sequence was obtained and analyzed. The NrS-1 genome is linear, circularly permuted, and terminally redundant. The NrS-1 genome is 37,159 bp in length and contains 51 coding sequences. Five major structural proteins including major capsid protein and tape measure protein were identified by SDS-PAGE and mass spectrometry analysis. NrS-1 belongs to the family Siphoviridae, but its sequence and genomic organization are distinct from those of any other previously known Siphoviridae phages. Homologues of genes encoded in the NrS-1 genome were widely distributed among the genomes of diverse Epsilonproteobacteria. The distribution patterns had little relation to the evolutionary traits and ecological and physiological differentiation of the host epsilonproteobacterial species. The widespread occurrence of phage genes in diverse Epsilonproteobacteria supports early co-evolution between temperate phages and Epsilonproteobacteria prior to the divergence of their habitats and physiological adaptation.

Complete genome sequence of the aerobic, heterotroph Marinithermus hydrothermalis type strain (T1(T)) from a deep-sea hydrothermal vent chimney.

Marinithermus hydrothermalis Sako et al. 2003 is the type species of the monotypic genus Marinithermus. M. hydrothermalis T1T was the first isolate within the phylum “Thermus-Deinococcus” to exhibit optimal growth under a salinity equivalent to that of sea water and to have an absolute requirement for NaCl for growth. M. hydrothermalis T1T is of interest because it may provide a new insight into the ecological significance of the aerobic, thermophilic decomposers in the circulation of organic compounds in deep-sea hydrothermal vent ecosystems. This is the first completed genome sequence of a member of the genus Marinithermus and the seventh sequence from the family Thermaceae. Here we describe the features of this organism, together with the complete genome sequence and annotation. The 2,269,167 bp long genome with its 2,251 protein-coding and 59 RNA genes is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

海底熱水系の物理・化学的多様性と化学合成微生物生態系の存在様式

Deep-sea hydrothermal vents are among the habitats that host the most diverse microbial communities on the Earth. It is promised that hydrothermal vent microbial communities play a major role in the circulation of energy and materials in the global oceanic and suboceanic environments, and even provide important insights into the origin and early evolution of life on the Earth and extraterrestrial life on other planets and moons. Deep-sea hydrothermal vent ecosystems are strongly dependent on the primary production of symbiotic and free-living chemolithoautotrophic microorganisms that can obtain energy from inorganic substances such as H2S, CO2, H2, and CH4 derived from hydrothermal vent fluids. The diversity and abundance of these energy and carbon sources at hydrothermal vent fluids are, in turn, controlled by subseafloor physical and chemical processes such as fluid–rock interactions and phase-separation and -partition of fluids. Therefore, linkage between rock (magma), hydrothermal fluid, and ecosystem is a key to understanding how deep-sea hydrothermal ecosystems are generated and sustained. In this article, we approach this whole “Rock–Fluid–Ecosystem linkage” with the two separate sub-linkages of “Rock–Fluid linkage” and “Fluid–Ecosystem linkage”, which have not been addressed by the individual research fields of the Geochemistry of Hydrothermal Systems and Hydrothermal Vent Microbiology, respectively. Here, we overview the progress of understanding the “Rock–Fluid” and “Fluid–Ecosystem” linkages, both of which will establish the basis for an integrated “Rock–Fluid–Ecosystem linkage”. (View PDF for the rest of the abstract.)

Variation in Sulfur Speciation with Shellfish Presence at a Lau Basin Diffuse Flow Vent Site

Carbon fixation by sulfur-oxidizing chemosynthetic bacteria forms the base of the food chain in deep-sea (diffuse-flow) hydrothermal vent ecosystems. Temperature and the availability of oxygen and reduced sulfur are believed to be factors that contribute to the structure of hydrothermal vent communities. Sulfur concentration and speciation can change rapidly as highly reducing vent fluids mix with cold oxygenated seawater, thus the path followed by source water before passing over organisms hosting sulfur-oxidizing endosymbionts may have important implications for these animals. Here we show an apparent correlation between the zonation of symbiont-containing species and the sulfur chemical speciation (sulfide, polysulfides, thiosulfate) in the water bathing them. We also report in-situ measurements of thiosulfate (S2O3 2−) in hydrothermal fluids, predominantly in the area inhabited by the mussel, Bathymodiolus brevior. These results provide field evidence of environmental levels of thiosulfate that may be capable of supporting thiosulfate-utilizing symbionts at hydrothermal vents. The three dominant shellfish species were arranged concentrically in a distinct bull's eye pattern at our study site. Alviniconcha sp. 1 snails inhabited the central, most reducing sulfide-rich zone, Ifremeria nautilei snails formed a thin band surrounding the Alviniconcha, and B. brevior mussels were farthest away from the source fluid in the most oxidized region. After removal of many of the Alviniconcha, some I. nautilei moved into the vacated space, whereas the B. brevior remained around the extreme periphery of the area impacted by the diffuse flow. These results suggest that diffuse flow chemistry is one of the key parameters affecting organism distribution.

POM in macro-/meiofaunal food webs associated with three flow regimes at deep-sea hydrothermal vents on Axial Volcano, Juan de Fuca Ridge

Deep-sea hydrothermal vent ecosystems host both symbiotic and non-symbiotic invertebrates. The non-symbiotic vent fauna is generally assumed to rely on free-living chemoautotrophic bacteria as their main food source but other sources such as detritus have recently been suggested to be a part of the invertebrate diets. Little is known about how food availability influences the distribution of vent organisms on a small scale. In addition, the feeding ecology and role of small, often numerically dominant invertebrates, the meiofauna is poorly understood at vents. In this study, we used stable carbon and nitrogen isotopic analysis to investigate the role of particulate detritus in the diets of macro- and meiobenthic invertebrates within three vent assemblages at Axial Volcano, Juan de Fuca Ridge, and Northeast Pacific. Particulate organic matter of a detrital origin became more important in the diet of invertebrates in assemblages typically associated with low-hydrothermal flow intensities. Meiobenthic species occupied several different feeding guilds and trophic levels in the assemblages investigated. We conclude that small-scale spatial variability in food sources is an important feature of vent food webs and that spatial patterns observed here and elsewhere are shaped by variations in hydrothermal discharge.

Community structure of mussel beds at deep-sea hydrothermal vents

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 230:137-158 (2002) - doi:10.3354/meps230137 Community structure of mussel beds at deep-sea hydrothermal vents Cindy Lee Van Dover* Biology Department, College of William & Mary, Williamsburg, Virginia 23187, USA *E-mail: cindy_vandover@wm.edu ABSTRACT: Definition of biogeographic provinces, patterns of species distributions on local and regional scales, species richness, and relative abundances are all basic ecological measures, yet they are largely unknown for deep-sea hydrothermal vent ecosystems. Without an appreciation of biogeographic and biodiversity patterns, it is difficult to understand the evolutionary and ecological processes that underlie species distributions. To begin to address these issues, species composition, species richness, diversity, abundance, and recruitment patterns were studied within mussel beds at 3 remote hydrothermal fields on the southern East Pacific Rise (SEPR). Two closely spaced fields (within 1 km) were hydrothermally active and shared the most abundant taxa. The mussel bed communities at these fields could be differentiated primarily by the relative abundances of species rather than by species composition. A third field was in a waning stage of hydrothermal activity. Productivity, biomass, and abundance of invertebrates associated with mussel beds at this third field were low, and the species list was a small subset of that found at the active fields, subsidized by several non-vent deep-sea taxa. Based on abundances of smallest size classes, recruitment of mussels and of several other dominant invertebrate species was high at the active sites. At the waning vent field, no recruitment was observed, except within the population of ophiuroids. Most of the species found within the SEPR mussel beds belong to species previously described from vent sites north of the equator, indicating that there is a single hydrothermal biogeographic province extending along the East Pacific Rise for more than 30 degrees of latitude. There were no shared species between SEPR mussel beds and a Mid-Atlantic Ridge (MAR) vent mussel bed and species richness was more than twice as high at the active SEPR mussel beds than at the Mid-Atlantic Ridge mussel beds. As biogeographic provinces are defined and robust measures of species diversity accumulate for vent habitats on the East Pacific Rise and Mid-Atlantic Ridge, vent ecologists will be able to place the biogeography and biodiversity of vent faunas within the context of the regional and global biogeographic and diversity patterns observed in terrestrial and other marine ecosystems. KEY WORDS: Hydrothermal vent · Diversity · Mussels · Bathymodiolus · Biogeography · Community structure Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 230. Online publication date: April 05, 2002 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2002 Inter-Research.

Formula omitted] values of lipids from phototrophic zone microplankton and bathypelagic shrimps at the Azores sector of the Mid-Atlantic Ridge

The lipid composition and δ 13 C values of phototrophic zone microplankton, and species of bathypelagic shrimp that are not associated with hydrothermal vents, were determined for samples collected from the water column above the Mid-Atlantic Ridge. These analyses were compared with similar previously published data for vent bresiliid shrimp to address the hypothesis that deep-sea hydrothermal vent ecosystems are reliant on specific dietary nutrients produced by photosynthetic organisms. Microplankton (<200 μm) sampled from the surface layer (∼4 m deep) and from the region of maximum light scattering (LSM, 48–75 m deep) were analysed to determine δ 13 C values of individual fatty acids in particulate matter. The distributions of fatty acids in total lipid from the surface layer and from the LSM were very similar, with high levels (∼45% of the total) of saturated fatty acids, particularly 14 : 0, 16 : 0 and 18 : 0, and moderate amounts (∼31% of the total) of polyunsaturated fatty acids (PUFA), dominated by 22 : 6(n-3). δ 13 C values of fatty acids from the surface layer and LSM were also very similar (mean values of −27.6 and −28.8‰, respectively), with a range of values from −25.0 to −32.2‰ and PUFA being somewhat depleted in 13 C relative to saturated and monounsaturated fatty acids. Total lipid of abdominal muscle from three species of bathypelagic decapod shrimp, Ephyrina bidentata, Parapasiphaea sulcatifrons and Sergia japonicus collected from 2000 m contained 18 : 1(n-9), 16 : 0, 22 : 6(n-3) and 20 : 5(n-3) as major fatty acids in all cases. The fatty acids in total lipid from the wax ester-rich hepatopancreas of all three shrimps were dominated (∼50% of the total) by 18 : 1(n-9) and contained substantially lower levels of PUFA than muscle lipid. Total lipids from the hepatopancreas of E. bidentata and S. japonicus contained high levels of 22 : 1 alcohols and 16 : 0 alcohol, respectively, whereas total hepatopancreatic lipid from P. sulcatifrons contained mainly 18 : 1 alcohols and 16 : 0 alcohol. δ 13 C values for the fatty acids in the three species ranged from −22.4 to −30.7‰ for muscle (mean value −25.7‰) and from −23.9 to −31.9‰ for hepatopancreas (mean value −26.1‰), with PUFA again being depleted in 13 C relative to saturated and monounsaturated fatty acids. δ 13 C values for the fatty alcohols in the three species ranged from −25.7 to −29.5‰ (mean value −27.1‰). These lipid analytical and δ 13 C data are consistent with PUFAs in bathypelagic shrimps originating unmodified from PUFAs in the photic zone and wax esters in bathypelagic shrimps originating substantially from animal biosynthetic activity.