1. Studies on prokaryotic populations and processes in subseafloor sediments – an update

Parkes, RJ; Sass, Henrik; Cragg, Barry A.; Webster, Gordon; Roussel, Erwan G.; Weightman, Andrew J.

doi:10.1515/9783110300130.1

Cited by 6 publications

(4 citation statements)

References 61 publications

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“…With total cell counts of 10 3 –10 7 cells g −1 sediment, the microbial abundances of both submarine permafrost cores were within the range of cell counts found in terrestrial long‐term cryogenic formations such as frozen ground and buried soils [ Gilichinsky, ]. Cell numbers of C2 were comparable with microbial abundances from subseafloor sediments (10 6 –10 7 cells mL −1 sediment) [ Parkes et al, ]. The depth profiles of total DNA concentration, bacterial gene copy numbers, and total cell counts in both cores followed a similar trend.…”

Section: Discussionmentioning

confidence: 57%

The development of permafrost bacterial communities under submarine conditions

Mitzscherling

Winkel

Winterfeld

et al. 2017

J. Geophys. Res. Biogeosci.

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Submarine permafrost is more vulnerable to thawing than permafrost on land. Besides increased heat transfer from the ocean water, the penetration of salt lowers the freezing temperature and accelerates permafrost degradation. Microbial communities in thawing permafrost are expected to be stimulated by warming, but how they develop under submarine conditions is completely unknown. We used the unique records of two submarine permafrost cores from the Laptev Sea on the East Siberian Arctic Shelf, inundated about 540 and 2500 years ago, to trace how bacterial communities develop depending on duration of the marine influence and pore water chemistry. Combined with geochemical analysis, we quantified total cell numbers and bacterial gene copies and determined the community structure of bacteria using deep sequencing of the bacterial 16S rRNA gene. We show that submarine permafrost is an extreme habitat for microbial life deep below the seafloor with changing thermal and chemical conditions. Pore water chemistry revealed different pore water units reflecting the degree of marine influence and stages of permafrost thaw. Millennia after inundation by seawater, bacteria stratify into communities in permafrost, marine‐affected permafrost, and seabed sediments. In contrast to pore water chemistry, the development of bacterial community structure, diversity, and abundance in submarine permafrost appears site specific, showing that both sedimentation and permafrost thaw histories strongly affect bacteria. Finally, highest microbial abundance was observed in the ice‐bonded seawater unaffected but warmed permafrost of the longer inundated core, suggesting that permafrost bacterial communities exposed to submarine conditions start to proliferate millennia after warming.

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Section: Discussionmentioning

confidence: 57%

The development of permafrost bacterial communities under submarine conditions

Mitzscherling

Winkel

Winterfeld

et al. 2017

J. Geophys. Res. Biogeosci.

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“…It is well-established that microbes inhabiting deep-sea sediments represent a significant proportion of the biosphere (Danovaro et al, 2016). Their abundance and diversity are largely dependent on environmental conditions such as OM content and sediment texture (Parkes et al, 2014). Table 1A, summarizes the spatial variation of environmental characteristics of deep-sea in the three study locations.…”

Section: Environmental Factors and Heavy Metal Distribution In Deep-seamentioning

confidence: 99%

Exploring the hidden treasures: Deep-sea bacterial community structure in the Bay of Bengal and their metabolic profile

Verma,

Pandey,

Seleyi

et al. 2024

Front. Mar. Sci.

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Deep sea bacterial communities demonstrate remarkable adaptability to high-pressure environments coupled with low temperatures which has sparked curiosity about their diversity and exceptional metabolic pathways. Additionally, bacteria in the deep sea exert a substantial influence over various biogeochemical processes. To date, we have relatively very little information about the deep-sea bacterial communities and, they remain largely unexplored. We investigated the variability in the physicochemical conditions, heavy metals and their influence on deep-sea bacterial community structure across three different depths in the Bay of Bengal. The structural and metabolic diversity of deep-sea sediment microbial communities were examined through culture-based sequencing of 16S rRNA genes, ecto-enzymatic studies, and community-level physiological profiling. Bacillota was the most dominant phylum representing 61% of the cultured bacterial isolates, while the remaining belonged to Actinomycetota and Pseudomonodata. Five potential novel species belonging to the genera Fictibacillus, Lysinibacillus, Salinicola, Robertmurraya and Blastococcus were identified. The extracellular enzymatic activity was positive for >50% of the bacterial isolates, wherein the genera Bacillus and Micromonospora exhibited versatile profiles. High metabolic diversity was recorded through the carbon substrate utilization profiles indicating that microbial communities are active participants in biogeochemical cycles in the deep sea. The most prominently utilized carbon substrates were α-cyclodextrin, glucose-1-phosphate, D-xylose, glycogen, and 2-hydroxy benzoic acid which serve as organic substrates for microbial metabolism, facilitating the decomposition of organic matter and, recycling carbon in deep-sea ecosystems. Multivariate statistical analyses confirmed that the environmental variables had a profound influence on the bacterial community. The findings shed light on spatial variability in the bacterial community structure, enzyme activity and metabolic profiles, and enhance our understanding of Bay of Bengal deep-sea sedimentary microbial ecology.

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“…0.3 mbsf) have generally low numbers of prokaryotic cells, except Porto MV at 0.9 mbsf which had exceptionally high numbers (Supplementary Figures S6). Based on 16S rRNA gene sequences, microbial populations were dominated by methanogenic archaea (Methanosarcinales), anaerobic methaneoxidizing archaea (ANME), Bathyarchaeota, Lokiarchaeaota and bacteria such as, Atribacterota, Chloroflexota, Bacillota and Deltaproteobacteria (Supplementary Figures S2, S4, and S6) frequently found in other methane-rich sediments (Inagaki et al, 2006;Parkes et al, 2014;Vigneron et al, 2015;Katayama et al, 2016;Teske et al, 2021). Similar groups of archaea and bacteria have also been identified at submarine MVs from other locations including Håkon Mosby, Amsterdam, Napoli, Kazan, Chefren, Ryukyu Trench and Beaufort Sea MVs (Niemann et al, 2006b;Heijs et al, 2007;Omoregie et al, 2008;Lazar et al, 2011bLazar et al, , 2012Pachiadaki and Kormas, 2013;Hoshino et al, 2017;Lee et al, 2019) and from the Gulf of Cádiz (Captain Arutyunov MV, Niemann et al, 2006a;Mercator MV, Maignien et al, 2013).…”

Section: Mud Volcano Microbial Diversitymentioning

confidence: 99%

Methanogen activity and microbial diversity in Gulf of Cádiz mud volcano sediments

et al. 2023

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The Gulf of Cádiz is a tectonically active continental margin with over sixty mud volcanoes (MV) documented, some associated with active methane (CH4) seepage. However, the role of prokaryotes in influencing this CH4 release is largely unknown. In two expeditions (MSM1-3 and JC10) seven Gulf of Cádiz MVs (Porto, Bonjardim, Carlos Ribeiro, Captain Arutyunov, Darwin, Meknes, and Mercator) were analyzed for microbial diversity, geochemistry, and methanogenic activity, plus substrate amended slurries also measured potential methanogenesis and anaerobic oxidation of methane (AOM). Prokaryotic populations and activities were variable in these MV sediments reflecting the geochemical heterogeneity within and between them. There were also marked differences between many MV and their reference sites. Overall direct cell numbers below the SMTZ (0.2–0.5 mbsf) were much lower than the general global depth distribution and equivalent to cell numbers from below 100 mbsf. Methanogenesis from methyl compounds, especially methylamine, were much higher than the usually dominant substrates H2/CO2 or acetate. Also, CH4 production occurred in 50% of methylated substrate slurries and only methylotrophic CH4 production occurred at all seven MV sites. These slurries were dominated by Methanococcoides methanogens (resulting in pure cultures), and prokaryotes found in other MV sediments. AOM occurred in some slurries, particularly, those from Captain Arutyunov, Mercator and Carlos Ribeiro MVs. Archaeal diversity at MV sites showed the presence of both methanogens and ANME (Methanosarcinales, Methanococcoides, and ANME-1) related sequences, and bacterial diversity was higher than archaeal diversity, dominated by members of the Atribacterota, Chloroflexota, Pseudomonadota, Planctomycetota, Bacillota, and Ca. “Aminicenantes.” Further work is essential to determine the full contribution of Gulf of Cádiz mud volcanoes to the global methane and carbon cycles.

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1. Studies on prokaryotic populations and processes in subseafloor sediments – an update

Abstract: A g u lh a s R id g e M e te o r R is e Agulhas Basin Cape Basin AFRICA av er ag e wi nt er se a ice ed ge Southwest Indian Ridge 1092 703 0

Cited by 6 publications

References 61 publications

The development of permafrost bacterial communities under submarine conditions

The development of permafrost bacterial communities under submarine conditions

Exploring the hidden treasures: Deep-sea bacterial community structure in the Bay of Bengal and their metabolic profile

Methanogen activity and microbial diversity in Gulf of Cádiz mud volcano sediments

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