Significant role of organic sulfur in supporting sedimentary sulfate reduction in low-sulfate environments

Fakhraee, Mojtaba; Li, Jiying; Katsev, Sergei

doi:10.1016/j.gca.2017.07.021

Cited by 51 publications

(50 citation statements)

References 87 publications

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“…Additionally, the source of sulphate and its isotopic signature are important to know, in order to derive fractionation values. While most sulphate in marine settings comes from bottom water sulphate, some fraction comes from the oxidation of organic sulphur compounds in particulate organic matter 47 . A lot of work has gone into elucidating the cryptic nature of the marine sulphur cycle, but it remains difficult to determine a quantitative relationship between oxygen concentration and sulphur isotope fractionation on a global scale, due to the nature of this cycling, which may have also changed over geologic time.…”

Section: Resultsmentioning

confidence: 99%

Stepwise oxygenation of the Paleozoic atmosphere

et al. 2018

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Oxygen is essential for animal life, and while geochemical proxies have been instrumental in determining the broad evolutionary history of oxygen on Earth, much of our insight into Phanerozoic oxygen comes from biogeochemical modelling. The GEOCARBSULF model utilizes carbon and sulphur isotope records to produce the most detailed history of Phanerozoic atmospheric O2 currently available. However, its predictions for the Paleozoic disagree with geochemical proxies, and with non-isotope modelling. Here we show that GEOCARBSULF oversimplifies the geochemistry of sulphur isotope fractionation, returning unrealistic values for the O2 sourced from pyrite burial when oxygen is low. We rebuild the model from first principles, utilizing an improved numerical scheme, the latest carbon isotope data, and we replace the sulphur cycle equations in line with forwards modelling approaches. Our new model, GEOCARBSULFOR, produces a revised, highly-detailed prediction for Phanerozoic O2 that is consistent with available proxy data, and independently supports a Paleozoic Oxygenation Event, which likely contributed to the observed radiation of complex, diverse fauna at this time.

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Section: Resultsmentioning

confidence: 99%

Stepwise oxygenation of the Paleozoic atmosphere

et al. 2018

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“…Organosulfur compounds can be particularly abundant in coastal marine environments ( Glockner et al, 2003 ) and genes encoding sulfatases are frequently found in marine sediment metagenomes ( Quaiser et al, 2011 ). Organic sulfur can be a significant source of sulfate especially in low sulfate sediment environments ( King and Klug, 1980 ; Fakhraee et al, 2017 ) and can fuel up to 50% of sulfate reduction in marine sediments by in situ production of sulfate ( Fakhraee et al, 2017 ). Abundant marine subsurface Dehalococcoidia, which are well represented in Aarhus Bay sediments ( Wasmund et al, 2014 ; Starnawski et al, 2017 ) also encode sulfatases in their genome ( Wasmund et al, 2014 ) suggesting that utilization of sulfonated organic compounds is a common feature among abundant subsurface microorganisms.…”

Section: Resultsmentioning

confidence: 99%

Single-Cell Genomics Reveals a Diverse Metabolic Potential of Uncultivated Desulfatiglans-Related Deltaproteobacteria Widely Distributed in Marine Sediment

et al. 2018

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Desulfatiglans-related organisms comprise one of the most abundant deltaproteobacterial lineages in marine sediments where they occur throughout the sediment column in a gradient of increasing sulfate and organic carbon limitation with depth. Characterized Desulfatiglans isolates are dissimilatory sulfate reducers able to grow by degrading aromatic hydrocarbons. The ecophysiology of environmental Desulfatiglans-populations is poorly understood, however, possibly utilization of aromatic compounds may explain their predominance in marine subsurface sediments. We sequenced and analyzed seven Desulfatiglans-related single-cell genomes (SAGs) from Aarhus Bay sediments to characterize their metabolic potential with regard to aromatic compound degradation and energy metabolism. The average genome assembly size was 1.3 Mbp and completeness estimates ranged between 20 and 50%. Five of the SAGs (group 1) originated from the sulfate-rich surface part of the sediment while two (group 2) originated from sulfate-depleted subsurface sediment. Based on 16S rRNA gene amplicon sequencing group 2 SAGs represent the more frequent types of Desulfatiglans-populations in Aarhus Bay sediments. Genes indicative of aromatic compound degradation could be identified in both groups, but the two groups were metabolically distinct with regard to energy conservation. Group 1 SAGs carry a full set of genes for dissimilatory sulfate reduction, whereas the group 2 SAGs lacked any genetic evidence for sulfate reduction. The latter may be due to incompleteness of the SAGs, but as alternative energy metabolisms group 2 SAGs carry the genetic potential for growth by acetogenesis and fermentation. Group 1 SAGs encoded reductive dehalogenase genes, allowing them to access organohalides and possibly conserve energy by their reduction. Both groups possess sulfatases unlike their cultured relatives allowing them to utilize sulfate esters as source of organic carbon and sulfate. In conclusion, the uncultivated marine Desulfatiglans populations are metabolically diverse, likely reflecting different strategies for coping with energy and sulfate limitation in the subsurface seabed.

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“…Another important, yet largely overlooked component of the sulfur cycle involves the utilisation and formation of organo-sulfur molecules (OSM). These labile metabolites including sulfonate (compounds with a R-SO 3 − functional group) and sulfonium such as dimethylsulphoniopropionate (DMSP) are produced by macroand micro-algae and may represent an important source of sulfur for certain microorganisms in freshwaters [12,13] and oceans, where genetic potential for transformation of OSM is widespread in marine bacteria [14].…”

Section: Page 3/26mentioning

confidence: 99%

Sulfur intermediates as new biogeochemical hubs in an aquatic model microbial ecosystem

Vigneron

Cruaud

Culley

et al. 2020

Preprint

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BackgroundThe sulfur cycle encompasses a series of complex aerobic and anaerobic transformations of S-containing molecules, and plays a fundamental role in cellular and ecosystems level-processes, influencing biological carbon transfers and other biogeochemical cycles. Despite their importance, the microbial communities and metabolic pathways involved in these transformations remain poorly understood, notably for inorganic sulfur compounds of intermediate oxidation states (thiosulfate, tetrathionate, sulfite, polysulfides). Isolated and highly stratified, the extreme geochemical and environmental contexts of the meromictic ice-capped Lake A, in the Canadian High Arctic, provides an outstanding model ecosystem to resolve the distribution and metabolism of aquatic sulfur cycling microorganisms along redox and salinity gradients. ResultsApplying complementary molecular approaches, we identified sharply contrasting microbial communities and metabolic potentials among the distinct water layers of the Lake A, with homologies to diverse fresh, brackish and saline water microbiomes. Sulfur cycling genes were abundant at all depths, with oxidative processes in the oxic freshwater layers, reductive reactions in the anoxic and sulfidic bottom waters and genes for both transformations at the chemocline, and co-varied with bacterial abundance. Up to 154 different genomic bins with potential for sulfur transformation were recovered, revealing a panoply of taxonomically diverse microorganisms with complex metabolic pathways for biogeochemical sulfur reactions. Metabolism of sulfur cycle intermediates was widespread throughout the water column, co-occurring with sulfate reduction or sulfide oxidation pathways. The genomic bin composition suggested that in addition to chemical oxidation, these intermediate sulfur compounds were likely produced by the predominant sulfur chemo- and photo-oxidizers at the chemocline and by diverse microbial organic sulfur molecule degraders. ConclusionsThe Lake A microbial ecosystem provided an ideal opportunity to identify new features of the biogeochemical sulfur cycle. Our detailed metagenomic analyses across the broad physico-chemical gradients of this highly stratified lake extend the known diversity of microorganisms and metabolic pathways involved in sulfur transformations over a wide range of environmental conditions. The results identify the importance of sulfur cycle intermediates and organic sulfur molecules as major sources of electron donors and acceptors for aquatic and sedimentary microbial communities in association with the classical sulfur cycle.

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Significant role of organic sulfur in supporting sedimentary sulfate reduction in low-sulfate environments

Cited by 51 publications

References 87 publications

Stepwise oxygenation of the Paleozoic atmosphere

Stepwise oxygenation of the Paleozoic atmosphere

Single-Cell Genomics Reveals a Diverse Metabolic Potential of Uncultivated Desulfatiglans-Related Deltaproteobacteria Widely Distributed in Marine Sediment

Sulfur intermediates as new biogeochemical hubs in an aquatic model microbial ecosystem

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