Deep Biosphere of the Oceanic Deep Sea

Encyclopedia of Geobiology - Encyclopedia of Earth Sciences Series ◽

10.1007/978-1-4020-9212-1_66 ◽

2011 ◽

pp. 317-322

Author(s):

Kristina Rathsack ◽

Nadia-Valérie Quéric ◽

Joachim Reitner

Keyword(s):

Deep Sea ◽

Deep Biosphere

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Comparative Metagenomic Analysis of a Microbial Community Residing at a Depth of 4,000 Meters at Station ALOHA in the North Pacific Subtropical Gyre

Applied and Environmental Microbiology ◽

10.1128/aem.00473-09 ◽

2009 ◽

Vol 75 (16) ◽

pp. 5345-5355 ◽

Cited By ~ 153

Author(s):

Konstantinos T. Konstantinidis ◽

Jennifer Braff ◽

David M. Karl ◽

Edward F. DeLong

Keyword(s):

Microbial Community ◽

Deep Sea ◽

Sea Water ◽

Sequence Data ◽

Deep Biosphere ◽

North Pacific Subtropical Gyre ◽

Selfish Genetic Elements ◽

The North ◽

Metabolic Versatility ◽

Station Aloha

ABSTRACT The deep sea (water depth of >2,000 m) represents the largest biome on Earth. Yet relatively little is known about its microbial community's structure, function, and adaptation to the cold and deep biosphere. To provide further genomic insights into deep-sea planktonic microbes, we sequenced a total of ∼200 Mbp of a random whole-genome shotgun (WGS) library from a microbial community residing at a depth of 4,000 m at Station ALOHA in the Pacific Ocean and compared it to other available WGS sequence data from surface and deep waters. Our analyses indicated that the deep-sea lifestyle is likely facilitated by a collection of very subtle adaptations, as opposed to dramatic alterations of gene content or structure. These adaptations appear to include higher metabolic versatility and genomic plasticity to cope with the sparse and sporadic energy resources available, a preference for hydrophobic and smaller-volume amino acids in protein sequences, unique proteins not found in surface-dwelling species, and adaptations at the gene expression level. The deep-sea community is also characterized by a larger average genome size and a higher content of “selfish” genetic elements, such as transposases and prophages, whose propagation is apparently favored by more relaxed purifying (negative) selection in deeper waters.

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Pathways for abiotic organic synthesis at submarine hydrothermal fields

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1506295112 ◽

2015 ◽

Vol 112 (25) ◽

pp. 7668-7672 ◽

Cited By ~ 146

Author(s):

Jill M. McDermott ◽

Jeffrey S. Seewald ◽

Christopher R. German ◽

Sean P. Sylva

Keyword(s):

Organic Compounds ◽

Organic Synthesis ◽

Deep Sea ◽

Hot Springs ◽

Hydrothermal Systems ◽

Deep Biosphere ◽

Shallow Subsurface ◽

Microbial Life ◽

Abiotic Organic Synthesis ◽

Life On Earth

Arguments for an abiotic origin of low-molecular weight organic compounds in deep-sea hot springs are compelling owing to implications for the sustenance of deep biosphere microbial communities and their potential role in the origin of life. Theory predicts that warm H2-rich fluids, like those emanating from serpentinizing hydrothermal systems, create a favorable thermodynamic drive for the abiotic generation of organic compounds from inorganic precursors. Here, we constrain two distinct reaction pathways for abiotic organic synthesis in the natural environment at the Von Damm hydrothermal field and delineate spatially where inorganic carbon is converted into bioavailable reduced carbon. We reveal that carbon transformation reactions in a single system can progress over hours, days, and up to thousands of years. Previous studies have suggested that CH4 and higher hydrocarbons in ultramafic hydrothermal systems were dependent on H2 generation during active serpentinization. Rather, our results indicate that CH4 found in vent fluids is formed in H2-rich fluid inclusions, and higher n-alkanes may likely be derived from the same source. This finding implies that, in contrast with current paradigms, these compounds may form independently of actively circulating serpentinizing fluids in ultramafic-influenced systems. Conversely, widespread production of formate by ΣCO2 reduction at Von Damm occurs rapidly during shallow subsurface mixing of the same fluids, which may support anaerobic methanogenesis. Our finding of abiogenic formate in deep-sea hot springs has significant implications for microbial life strategies in the present-day deep biosphere as well as early life on Earth and beyond.

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Deep Sea Microbes Probed by Incoherent Neutron Scattering Under High Hydrostatic Pressure

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2014-0547 ◽

2014 ◽

Vol 228 (10-12) ◽

Cited By ~ 13

Author(s):

Judith Peters ◽

Nicolas Martinez ◽

Grégoire Michoud ◽

Anaïs Cario ◽

Bruno Franzetti ◽

...

Keyword(s):

High Pressure ◽

Hydrostatic Pressure ◽

Neutron Scattering ◽

Deep Sea ◽

High Hydrostatic Pressure ◽

Deep Biosphere ◽

Incoherent Neutron Scattering ◽

Incoherent Neutron ◽

High Pressure Environment ◽

Marine Biosphere

AbstractThe majority of the biosphere is a high pressure environment. Around 70% of the marine biosphere lies at depths below 1000 m, i.e. at pressures of 100 bars or higher. To survive in these environments, deep-biosphere organisms have adapted to life at high pressure.

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Geological processes mediate a subsurface microbial loop in the deep biosphere

10.1101/2021.10.26.465990 ◽

2021 ◽

Author(s):

Daniel Gittins ◽

Pierre-Arnaud Desiage ◽

Natasha Morrison ◽

Jayne E Rattray ◽

Srijak Bhatnagar ◽

...

Keyword(s):

Deep Sea ◽

Thermophilic Bacteria ◽

Microbial Loop ◽

Deep Biosphere ◽

Ecological Processes ◽

Petroleum Systems ◽

Environmental Selection ◽

Geological Processes ◽

Bacterial Endospores ◽

Migration Pathways

The deep biosphere is the largest microbial habitat on Earth and features abundant bacterial endospores1,2. Whereas dormancy and survival at theoretical energy minima are hallmarks of subsurface microbial populations3, the roles of fundamental ecological processes like dispersal and selection in these environments are poorly understood4. Here we combine geophysics, geochemistry, microbiology and genomics to investigate biogeography in the subsurface, focusing on bacterial endospores in a deep-sea setting characterized by thermogenic hydrocarbon seepage. Thermophilic endospores in permanently cold seabed sediments above petroleum seep conduits were correlated with the presence of hydrocarbons, revealing geofluid-facilitated cell migration pathways originating in deep oil reservoirs. Genomes of thermophilic bacteria highlight adaptations to life in anoxic petroleum systems and reveal that these dormant populations are closely related to oil reservoir microbiomes from around the world. After transport out of the subsurface and into the deep-sea, thermophilic endospores re-enter the geosphere by sedimentation. Viable thermophilic endospores spanning the top several metres of the seabed correspond with total endospore counts that are similar to or exceed the global average. Burial of dormant cells enables their environmental selection in sedimentary formations where new petroleum systems establish, completing a geological microbial loop that circulates living biomass in and out of the deep biosphere.

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