The fate of organic carbon in marine sediments - New insights from recent data and analysis

Earth-Science Reviews, Journal Year: 2020, Volume and Issue: 204, P. 103146 - 103146

Published: Feb. 29, 2020

Language: Английский

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Enigmatic persistence of dissolved organic matter in the ocean

Nature Reviews Earth & Environment, Journal Year: 2021, Volume and Issue: 2(8), P. 570 - 583

Published: June 30, 2021

Language: Английский

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Trace gas oxidizers are widespread and active members of soil microbial communities

Nature Microbiology, Journal Year: 2021, Volume and Issue: 6(2), P. 246 - 256

Published: Jan. 4, 2021

Language: Английский

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Sediment oxygen consumption: Role in the global marine carbon cycle

Earth-Science Reviews, Journal Year: 2022, Volume and Issue: 228, P. 103987 - 103987

Published: March 12, 2022

The seabed plays a key role in the marine carbon cycle as a) terminal location of aerobic oxidation organic matter, b) greatest anaerobic bioreactor, and c) repository for reactive on Earth. We compiled data oxygen uptake sediments with objective to understand constraints mineralization rates deposited matter their relation environmental parameters. database includes nearly 4000 O2 is available supplementary material. It also information bottom water concentration, penetration depth, geographic position, full sources. present different situ ex approaches measure total (TOU) diffusive (DOU) discuss robustness towards methodological errors statistical uncertainty. transport through benthic boundary layers, diffusion- fauna-mediated uptake, coupling respiration processes. Five regional examples are presented illustrate diversity seabed: Eutrophic seas, minimum zones, abyssal plains, mid-oceanic gyres, hadal trenches. A multiple correlation analysis shows that primarily controlled by ocean depth sea surface primary productivity. scales DOU according power law breaks down under gyres. developed model was used draw global map rates. Respiratory coefficients, differentiated regions ocean, were convert oxidation. resulting budget an 212 Tmol C yr−1 5-95% confidence interval 175-260 yr−1. comparison flux particulate (POC) from photic waters deep sea, determined sediment trap studies, suggests deficit sedimentation at 2000 m about 70% relative turnover underlying seabed. At margins, rivers vegetated coastal ecosystems contributes greatly may even exceed phytoplankton production inner continental shelf.

Language: Английский

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Long-term organic carbon preservation enhanced by iron and manganese

Nature, Journal Year: 2023, Volume and Issue: 621(7978), P. 312 - 317

Published: Aug. 2, 2023

Abstract The balance between degradation and preservation of sedimentary organic carbon (OC) is important for global oxygen cycles 1 . relative importance different mechanisms environmental conditions contributing to marine OC preservation, however, remains unclear 2–8 Simple molecules can be geopolymerized into recalcitrant forms by means the Maillard reaction 5 , although kinetics at temperatures are thought slow 9,10 More recent work in terrestrial systems suggests that catalysed manganese minerals 11–13 but potential promotion formation uncertain. Here we present incubation experiments find iron ions abiotically catalyse up two orders magnitude relevant continental margins where most occurs 4 Furthermore, chemical signature products closely resembles dissolved total found margin sediments globally. With aid a pore-water model 14 estimate iron- manganese-catalysed transformation simple complex macromolecules might generate on order approximately 4.1 Tg C yr −1 sediments. In context perhaps only about 63 variation over past 300 million years 6 propose variable inputs ocean could exert substantial hitherto unexplored impact geological time.

Language: Английский

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Hydrogen and dark oxygen drive microbial productivity in diverse groundwater ecosystems

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: June 13, 2023

Abstract Around 50% of humankind relies on groundwater as a source drinking water. Here we investigate the age, geochemistry, and microbiology 138 samples from 95 monitoring wells (<250 m depth) located in 14 aquifers Canada. The geochemistry show consistent trends suggesting large-scale aerobic anaerobic hydrogen, methane, nitrogen, sulfur cycling carried out by diverse microbial communities. Older groundwaters, especially with organic carbon-rich strata, contain average more cells (up to 1.4 × 10 7 mL −1 ) than younger challenging current estimates subsurface cell abundances. We observe substantial concentrations dissolved oxygen (0.52 ± 0.12 mg L [mean SE]; n = 57) older groundwaters that seem support metabolisms ecosystems at an unprecedented scale. Metagenomics, isotope analyses mixing models indicate dark is produced situ via dismutation. ancient sustain productive communities highlight overlooked present past Earth.

Language: Английский

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Preservation of organic carbon in marine sediments sustained by sorption and transformation processes

Nature Geoscience, Journal Year: 2025, Volume and Issue: 18(1), P. 78 - 83

Published: Jan. 1, 2025

Abstract Controls on organic carbon preservation in marine sediments remain controversial but crucial for understanding past and future climate dynamics. Here we develop a conceptual-mathematical model to determine the key processes of carbon. The considers major involved breakdown carbon, including dissolved hydrolysis, mixing, remineralization, mineral sorption molecular transformation. This allows redefining burial efficiency as efficiency, which both particulate mineral-phase We show that is almost three times higher than conventionally defined reconciles predictions with global field data. Kinetic transformation are dominant controls preservation. conclude synergistic effect between kinetic (geopolymerization) creates shuttle protected from remineralization surface sediment released at depth. results explain why transformed persists over long timescales increases

Language: Английский

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Chemosynthetic and photosynthetic bacteria contribute differentially to primary production across a steep desert aridity gradient

The ISME Journal, Journal Year: 2021, Volume and Issue: 15(11), P. 3339 - 3356

Published: May 25, 2021

Abstract Desert soils harbour diverse communities of aerobic bacteria despite lacking substantial organic carbon inputs from vegetation. A major question is therefore how these maintain their biodiversity and biomass in resource-limiting ecosystems. Here, we investigated desert topsoils biological soil crusts collected along an aridity gradient traversing four climatic regions (sub-humid, semi-arid, arid, hyper-arid). Metagenomic analysis indicated vary capacity to use sunlight, compounds, inorganic compounds as energy sources. Thermoleophilia, Actinobacteria, Acidimicrobiia were the most abundant prevalent bacterial classes across both biocrusts. Contrary classical view that taxa are obligate organoheterotrophs, genome-resolved suggested they metabolically flexible, with also atmospheric H2 support respiration often fixation. In contrast, Cyanobacteria patchily distributed only certain Activity measurements profiled oxidation, chemosynthetic CO2 fixation, photosynthesis varied aridity. Cell-specific rates consumption increased 143-fold gradient, correlating abundance high-affinity hydrogenases. Photosynthetic primary production co-occurred throughout dominant biocrusts chemosynthesis arid hyper-arid soils. Altogether, findings suggest lineages inhabiting hot deserts different strategies for acquisition depending on resource availability. Moreover, highlight previously overlooked roles Actinobacteriota producers trace gases critical sources supporting productivity resilience

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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Hydrogen-Oxidizing Bacteria Are Abundant in Desert Soils and Strongly Stimulated by Hydration

mSystems, Journal Year: 2020, Volume and Issue: 5(6)

Published: Nov. 16, 2020

How the diverse bacterial communities inhabiting desert soils maintain energy and carbon needs is much debated. Traditionally, most bacteria are thought to persist by using organic synthesized photoautotrophs following transient hydration events. Recent studies focused on Antarctic have revealed, however, that some use atmospheric trace gases, such as hydrogen (H

Language: Английский

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