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1.
Geobiology ; 20(6): 823-836, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35993193

RESUMO

Recent studies have reported up to 1.9 × 1029 bacterial endospores in the upper kilometre of deep subseafloor marine sediments, however, little is understood about their origin and dispersal. In cold ocean environments, the presence of thermospores (endospores produced by thermophilic bacteria) suggests that distribution is governed by passive migration from warm anoxic sources possibly facilitated by geofluid flow, such as advective hydrocarbon seepage sourced from petroleum deposits deeper in the subsurface. This study assesses this hypothesis by measuring endospore abundance and distribution across 60 sites in Eastern Gulf of Mexico (EGM) sediments using a combination of the endospore biomarker 2,6-pyridine dicarboxylic acid or 'dipicolinic acid' (DPA), sequencing 16S rRNA genes of thermospores germinated in 50°C sediment incubations, petroleum geochemistry in the sediments and acoustic seabed data from sub-bottom profiling. High endospore abundance is associated with geologically active conduit features (mud volcanoes, pockmarks, escarpments and fault systems), consistent with subsurface fluid flow dispersing endospores from deep warm sources up into the cold ocean. Thermospores identified at conduit sites were most closely related to bacteria associated with the deep biosphere habitats including hydrocarbon systems. The high endospore abundance at geological seep features demonstrated here suggests that recalcitrant endospores and their chemical components (such as DPA) can be used in concert with geochemical and geophysical analyses to locate discharging seafloor features. This multiproxy approach can be used to better understand patterns of advective fluid flow in regions with complex geology like the EGM basin.


Assuntos
Sedimentos Geológicos , Petróleo , Bactérias , Sedimentos Geológicos/microbiologia , Golfo do México , Hidrocarbonetos/análise , RNA Ribossômico 16S/genética , Esporos Bacterianos/química , Esporos Bacterianos/genética
2.
Nat Commun ; 10(1): 1816, 2019 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-31000700

RESUMO

The lack of microbial genomes and isolates from the deep seabed means that very little is known about the ecology of this vast habitat. Here, we investigate energy and carbon acquisition strategies of microbial communities from three deep seabed petroleum seeps (3 km water depth) in the Eastern Gulf of Mexico. Shotgun metagenomic analysis reveals that each sediment harbors diverse communities of chemoheterotrophs and chemolithotrophs. We recovered 82 metagenome-assembled genomes affiliated with 21 different archaeal and bacterial phyla. Multiple genomes encode enzymes for anaerobic oxidation of aliphatic and aromatic compounds, including those of candidate phyla Aerophobetes, Aminicenantes, TA06 and Bathyarchaeota. Microbial interactions are predicted to be driven by acetate and molecular hydrogen. These findings are supported by sediment geochemistry, metabolomics, and thermodynamic modelling. Overall, we infer that deep-sea sediments experiencing thermogenic hydrocarbon inputs harbor phylogenetically and functionally diverse communities potentially sustained through anaerobic hydrocarbon, acetate and hydrogen metabolism.


Assuntos
Archaea/metabolismo , Bactérias/metabolismo , Sedimentos Geológicos/microbiologia , Microbiota/fisiologia , Petróleo/metabolismo , Acetatos/metabolismo , Archaea/genética , Archaea/isolamento & purificação , Bactérias/genética , Bactérias/isolamento & purificação , Sedimentos Geológicos/química , Hidrocarbonetos/metabolismo , Hidrogênio/metabolismo , Metagenoma , Metagenômica/métodos , México , Interações Microbianas/fisiologia
3.
ISME J ; 12(8): 1895-1906, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29599524

RESUMO

Dormant endospores of thermophilic bacteria (thermospores) can be detected in cold marine sediments following high-temperature incubation. Thermospores in the cold seabed may be explained by a dispersal history originating in deep biosphere oil reservoir habitats where upward migration of petroleum fluids at hydrocarbon seeps transports viable cells into the overlying ocean. We assessed this deep-to-shallow dispersal hypothesis through geochemical and microbiological analyses of 111 marine sediments from the deep water Eastern Gulf of Mexico. GC-MS and fluorescence confirmed the unambiguous presence of thermogenic hydrocarbons in 71 of these locations, indicating seepage from deeply sourced petroleum in the subsurface. Heating each sediment to 50 °C followed by 16S rRNA gene sequencing revealed several thermospores with a cosmopolitan distribution throughout the study area, as well as thermospores that were more geographically restricted. Among the thermospores having a more limited distribution, 12 OTUs from eight different lineages were repeatedly detected in sediments containing thermogenic hydrocarbons. A subset of these were significantly correlated with hydrocarbons (p < 0.05) and most closely related to Clostridiales previously detected in oil reservoirs from around the world. This provides evidence of bacteria in the ocean being dispersed out of oil reservoirs, and suggests that specific thermospores may be used as model organisms for studying warm-to-cold transmigration in the deep sea.


Assuntos
Sedimentos Geológicos/microbiologia , Esporos Bacterianos/isolamento & purificação , Temperatura , Golfo do México , Hidrocarbonetos/análise , Petróleo
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