Microbial dormancy in the marine subsurface: Global endospore abundance and response to burial

Science Advances, Journal Year: 2019, Volume and Issue: 5(2)

Published: Feb. 1, 2019

Bacterial endospores are dominant members of the marine deep biosphere.

Language: Английский

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New Microbial Biodiversity in Marine Sediments

Annual Review of Marine Science, Journal Year: 2020, Volume and Issue: 13(1), P. 161 - 175

Published: Aug. 4, 2020

Microbes in marine sediments represent a large portion of the biosphere, and resolving their ecology is crucial for understanding global ocean processes. Single-gene diversity surveys have revealed several uncultured lineages that are widespread whose ecological roles unknown, advancements computational analysis increasingly genomic data sets made it possible to reconstruct individual genomes from complex microbial communities. Using these metagenomic approaches characterize transforming our view communities on floor biodiversity planet. In recent years, been prominent source new tree life. The incorporation into existing phylogenies has many belong distinct phyla, including archaeal phyla advancing origins cellular complexity eukaryotes. Detailed comparisons metabolic potentials clear bacteria archaea capable mediating key previously undescribed steps carbon nutrient cycling.

Language: Английский

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Mars Extant Life: What's Next? Conference Report

Astrobiology, Journal Year: 2020, Volume and Issue: 20(6), P. 785 - 814

Published: May 29, 2020

On November 5–8, 2019, the "Mars Extant Life: What's Next?" conference was convened in Carlsbad, New Mexico. The gathered a community of actively publishing experts disciplines related to habitability and astrobiology. Primary conclusions are as follows: A significant subset attendees concluded that there is realistic possibility Mars hosts indigenous microbial life. powerful theme permeated key search for martian extant life lies identifying exploring refugia ("oases"), where conditions either permanently or episodically significantly more hospitable than average. Based on our existing knowledge Mars, participants highlighted four potential refugium (not listed priority order): Caves, Deep Subsurface, Ices, Salts. group did not attempt reach consensus prioritization these candidate environments, but instead felt defensible would require future competitive process. Within context we identified variety geological strategies could narrow space. Additionally, summarized number measurement techniques be used detect evidence (if present). Again, it within scope prioritize techniques—that best left We specifically note sensitivity detection methods implemented if samples were returned Earth greatly exceed methodologies at Mars. Finally, important lessons guide processes can derived both from experiments carried out terrestrial laboratories analog field sites theoretical modeling.

Language: Английский

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Microbial Communities Involved in Methane, Sulfur, and Nitrogen Cycling in the Sediments of the Barents Sea

Microorganisms, Journal Year: 2021, Volume and Issue: 9(11), P. 2362 - 2362

Published: Nov. 15, 2021

A combination of physicochemical and radiotracer analysis, high-throughput sequencing the 16S rRNA, particulate methane monooxygenase subunit (pmoA) genes was used to link a microbial community profile with methane, sulfur, nitrogen cycling processes. The objects study were surface sediments sampled at five stations in northern part Barents Sea. content upper layers (0–5 cm) ranged from 0.2 2.4 µM increased depth (16–19 9.5 µM. rate oxidation oxic varied 2 23 nmol CH4 L−1 day−1 decreased 0.3 anoxic zone 16–19 cm. Sulfate reduction rates much higher, 2.8 µmol day−1. In sediments, ammonia-oxidizing Nitrosopumilaceae abundant; subsequent nitrite nitrate can be carried out by Nitrospira sp. Aerobic could performed uncultured deep-sea cluster 3 gamma-proteobacterial methanotrophs. Undetectable low levels methanogenesis consistent near complete absence methanogens. Anaerobic deeper likely ANME-2a-2b ANME-2c archaea consortium sulfate-reducing Desulfobacterota. Sulfide oxidized nitrate-reducing Sulfurovum Thus, sulfur cycle linked anaerobic cycle, which included ammonium denitrification coupled sulfide sediments. Methane concentrations biogeochemical processes Sea noticeably higher than oligotrophic areas Arctic Ocean, indicating that an increase concentration significantly activates

Language: Английский

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Sulfur Biogeochemical Cycle of Marine Sediments

Geochemical Perspectives, Journal Year: 2021, Volume and Issue: unknown, P. 145 - 307

Published: Oct. 1, 2021

Complex interactions between microbial communities and geochemical processes drive the major element cycles control function of marine sediments as a dynamic reservoir organic matter. Sulfate reduction is globally dominant pathway anaerobic mineralisation main source sulfide. The effective re-oxidation this sulfide at direct or indirect expense oxygen prerequisite for aerobic life on our planet. Although largely hidden beneath oxic sediment surface, sulfur cycle therefore critical Earth’s redox state. This Geochemical Perspectives begins with brief primer description my own scientific journey through nearly fifty years studies geochemistry microbiology. Among objectives these were to quantify identify behind them. Radiotracers in combination chemical analyses have thereby been used extensively laboratory experiments, supported by diverse molecular microbiological methods. following sections discuss sulfate reduction, oxidation disproportionation inorganic intermediates, especially elemental thiosulfate. experimental approaches enable analysis how environmental factors such substrate concentration temperature affect process rates concurrent cryptic cycle. energy chemolithotrophic bacteria, including fascinating big bacteria cable supports their dark CO2 fixation, which produces new biomass. During burial aging sediments, predominant change cascade reactions, rate matter degradation drops continuously over many orders magnitude. pathways age turnover are discussed. In deep methanic zone, only few percent entire remains, provides small boost methane oxidation. stable isotopes provide an additional tool understand diagenetic processes, whereby isotope fractionation open system diagenesis generate differential diffusion flux isotopes. relation carbon seabed contribution methane, paper discusses global budget role different depth regions ocean – from coast sea. published estimates parameters evaluated compared. Finally, looks future perspectives respect gaps current understanding need further studies.

Language: Английский

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