scholarly journals Arsenic binding to organic and inorganic sulfur species during microbial sulfate reduction: a sediment flow-through reactor experiment

2013 ◽  
Vol 10 (4) ◽  
pp. 285 ◽  
Author(s):  
Raoul-Marie Couture ◽  
Dirk Wallschläger ◽  
Jérôme Rose ◽  
Philippe Van Cappellen
Keyword(s):  
Organic Matter ◽  
Sulfate Reduction ◽  
Iron Concentration ◽  
Labile Organic Matter ◽  
Sulfur Species ◽  
Sulfate Reducing ◽  
Arsenic Mobility ◽  
Microbial Sulfate Reduction ◽  
Reducing Conditions ◽  
Flow Through

Environmental context The use of water contaminated with arsenic for drinking and irrigation is linked to water and food borne diseases throughout the world. Although reducing conditions in soils and sediments are generally viewed as enhancing arsenic mobility in subsurface environments, we show they can actually promote As sequestration in the presence of reduced sulfur species and labile organic matter. We propose that sulfurisation of organic matter and subsequent binding of As to thiol groups may offer an innovative pathway for As remediation. Abstract Flow-through reactors (FTRs) were used to assess the mobility of arsenic under sulfate reducing conditions in natural, undisturbed lake sediments. The sediment slices in the FTRs were supplied continuously with inflow solutions containing sulfate and soluble AsIII or AsV and, after 3 weeks, also lactate. The experiment ran for a total of 8 weeks. The dissolved iron concentration, pH, redox potential (Eh), as well as aqueous As and sulfur speciation were monitored in the outflow solutions. In FTRs containing surface sediment enriched in labile organic matter (OM), microbial sulfate reduction led to an accumulation of organically bound S, as evidenced by X-ray absorption spectroscopy. For these FTRs, the inflowing dissolved As concentration of 20μM was lowered by two orders of magnitude, producing outflow concentrations of 0.2μM monothioarsenate and 0.1μM arsenite. In FTRs containing sediment collected at greater depth, sulfide and zero-valent S precipitated as pyrite and elemental S, while steady-state outflow arsenite concentrations remained near 5μM. The observations thus suggest that As sequestration is enhanced when sediment OM buffers the free sulfide and zero-valent S concentrations. An updated conceptual model for the fate of As in the anoxic As–C–S–Fe system is presented based on the results of this study.

scholarly journals Complex Microbial Communities Drive Iron and Sulfur Cycling in Arctic Fjord Sediments

2019 ◽  
Vol 85 (14) ◽  
Author(s):  
J. Buongiorno ◽  
L. C. Herbert ◽  
L. M. Wehrmann ◽  
A. B. Michaud ◽  
K. Laufer ◽  
...  
Keyword(s):  
Organic Matter ◽  
Primary Production ◽  
Sulfate Reduction ◽  
The Arctic ◽  
Sulfur Cycling ◽  
Glacial Retreat ◽  
Sulfate Reducing ◽  
Glacial Runoff ◽  
Sulfate Reduction Rates ◽  
Fjord Sediments

ABSTRACTGlacial retreat is changing biogeochemical cycling in the Arctic, where glacial runoff contributes iron for oceanic shelf primary production. We hypothesize that in Svalbard fjords, microbes catalyze intense iron and sulfur cycling in low-organic-matter sediments. This is because low organic matter limits sulfide generation, allowing iron mobility to the water column instead of precipitation as iron monosulfides. In this study, we tested this with high-depth-resolution 16S rRNA gene libraries in the upper 20 cm at two sites in Van Keulenfjorden, Svalbard. At the site closer to the glaciers, iron-reducingDesulfuromonadales, iron-oxidizingGallionellaandMariprofundus, and sulfur-oxidizingThiotrichalesandEpsilonproteobacteriawere abundant above a 12-cm depth. Below this depth, the relative abundances of sequences for sulfate-reducingDesulfobacteraceaeandDesulfobulbaceaeincreased. At the outer station, the switch from iron-cycling clades to sulfate reducers occurred at shallower depths (∼5 cm), corresponding to higher sulfate reduction rates. Relatively labile organic matter (shown by δ13C and C/N ratios) was more abundant at this outer site, and ordination analysis suggested that this affected microbial community structure in surface sediments. Network analysis revealed more correlations between predicted iron- and sulfur-cycling taxa and with uncultured clades proximal to the glacier. Together, these results suggest that complex microbial communities catalyze redox cycling of iron and sulfur, especially closer to the glacier, where sulfate reduction is limited due to low availability of organic matter. Diminished sulfate reduction in upper sediments enables iron to flux into the overlying water, where it may be transported to the shelf.IMPORTANCEGlacial runoff is a key source of iron for primary production in the Arctic. In the fjords of the Svalbard archipelago, glacial retreat is predicted to stimulate phytoplankton blooms that were previously restricted to outer margins. Decreased sediment delivery and enhanced primary production have been hypothesized to alter sediment biogeochemistry, wherein any free reduced iron that could potentially be delivered to the shelf will instead become buried with sulfide generated through microbial sulfate reduction. We support this hypothesis with sequencing data that showed increases in the relative abundance of sulfate reducing taxa and sulfate reduction rates with increasing distance from the glaciers in Van Keulenfjorden, Svalbard. Community structure was driven by organic geochemistry, suggesting that enhanced input of organic material will stimulate sulfate reduction in interior fjord sediments as glaciers continue to recede.

scholarly journals Effects of Iron and Nitrogen Limitation on Sulfur Isotope Fractionation during Microbial Sulfate Reduction

2012 ◽  
Vol 78 (23) ◽  
pp. 8368-8376 ◽  
Author(s):  
Min Sub Sim ◽  
Shuhei Ono ◽  
Tanja Bosak
Keyword(s):  
Nitrogen Fixation ◽  
Sulfate Reduction ◽  
Isotope Fractionation ◽  
Sulfur Isotope ◽  
Isotope Effects ◽  
Reducing Power ◽  
Sulfate Reducing ◽  
Microbial Sulfate Reduction ◽  
Sulfur Isotope Fractionation ◽  
S Isotope

ABSTRACTSulfate-reducing microbes utilize sulfate as an electron acceptor and produce sulfide that is depleted in heavy isotopes of sulfur relative to sulfate. Thus, the distribution of sulfur isotopes in sediments can trace microbial sulfate reduction (MSR), and it also has the potential to reflect the physiology of sulfate-reducing microbes. This study investigates the relationship between the availability of iron and reduced nitrogen and the magnitude of S-isotope fractionation during MSR by a marine sulfate-reducing bacterium, DMSS-1, aDesulfovibriospecies, isolated from salt marsh in Cape Cod, MA. Submicromolar levels of iron increase sulfur isotope fractionation by about 50% relative to iron-replete cultures of DMSS-1. Iron-limited cultures also exhibit decreased cytochromec-to-total protein ratios and cell-specific sulfate reduction rates (csSRR), implying changes in the electron transport chain that couples carbon and sulfur metabolisms. When DMSS-1 fixes nitrogen in ammonium-deficient medium, it also produces larger fractionation, but it occurs at faster csSRRs than in the ammonium-replete control cultures. The energy and reducing power required for nitrogen fixation may be responsible for the reverse trend between S-isotope fractionation and csSRR in this case. Iron deficiency and nitrogen fixation by sulfate-reducing microbes may lead to the large observed S-isotope effects in some euxinic basins and various anoxic sediments.

scholarly journals Microbial methanogenesis in the sulfate-reducing zone of surface sediments traversing the Peruvian margin

2015 ◽  
Vol 12 (17) ◽  
pp. 14869-14910 ◽  
Author(s):  
J. Maltby ◽  
S. Sommer ◽  
A. W. Dale ◽  
T. Treude
Keyword(s):  
Sulfate Reduction ◽  
Surface Sediments ◽  
Carbon Export ◽  
Labile Organic Matter ◽  
Methanogenic Activity ◽  
Sulfate Reducing ◽  
Hydrogenotrophic Methanogenesis ◽  
Minimum Zone ◽  
Shelf Station ◽  
The Relationship

Abstract. We studied the concurrence of methanogenesis and sulfate reduction in surface sediments (0–25 cm below sea floor, cmbsf) at six stations (70, 145, 253, 407, 770 and 1024 m) along the Peruvian margin (12° S). This oceanographic region is characterized by high carbon export to the seafloor, creating an extensive oxygen minimum zone (OMZ) on the shelf, both factors that could favor surface methanogenesis. Sediments sampled along the depth transect traversed areas of anoxic and oxic conditions in the bottom-near water. Net methane production (batch incubations) and sulfate reduction (35S-sulfate radiotracer incubation) were determined in the upper 0–25 cmbsf of multicorer cores from all stations, while deep hydrogenotrophic methanogenesis (> 30 cmbsf, 14C-bicarbonate radiotracer incubation) was determined in two gravity cores at selected sites (78 and 407 m). Furthermore, stimulation (methanol addition) and inhibition (molybdate addition) experiments were carried out to investigate the relationship between sulfate reduction and methanogenesis. Highest rates of methanogenesis and sulfate reduction in the surface sediments, integrated over 0–25 cmbsf, were observed on the shelf (70–253 m, 0.06–0.1 and 0.5–4.7 mmol m−2 d−1, respectively), while lowest rates were discovered at the deepest site (1024 m, 0.03 and 0.2 mmol m−2 d−1, respectively). The addition of methanol resulted in significantly higher surface methanogenesis activity, suggesting that the process was mostly based on non-competitive substrates, i.e., substrates not used by sulfate reducers. In the deeper sediment horizons, where competition was probably relieved due to the decline of sulfate, the usage of competitive substrates was confirmed by the detection of hydrogenotrophic activity in the sulfate-depleted zone at the shallow shelf station (70 m). Surface methanogenesis appeared to be correlated to the availability of labile organic matter (C / N ratio) and organic carbon degradation (DIC production), both of which support the supply of methanogenic substrates. A negative correlation of methanogenesis rates with dissolved oxygen in the bottom-near water was not obvious, however, anoxic conditions within the OMZ might be advantageous for methanogenic organisms at the sediment–water interface. Our results revealed a high relevance of surface methanogenesis on the shelf, where the ratio between surface to deep (below sulfate penetration) methanogenic activity ranged between 0.13 and 105. In addition, methane concentration profiles indicate a partial release of surface methane into the water column as well as a partial consumption of methane by anaerobic methane oxidation (AOM) in the surface sediment. The present study suggests that surface methanogenesis might play a greater role in benthic methane budgeting than previously thought, especially for fueling AOM above the sulfate-methane transition zone.

scholarly journals Expanded Genomic Sampling of the Desulfobulbales Reveals Distribution and Evolution of Sulfur Metabolisms

2021 ◽  
Author(s):  
Lewis M. Ward ◽  
Emma Bertran ◽  
David T. Johnston
Keyword(s):  
Sulfate Reduction ◽  
Sulfur Metabolism ◽  
Phylogenetic Analyses ◽  
Genomic Diversity ◽  
Test Case ◽  
Sulfur Disproportionation ◽  
Sulfate Reducing ◽  
Relative Contribution ◽  
Microbial Sulfate Reduction ◽  
Reducing Bacteria

AbstractThe reconstruction of modern and paleo-sulfur cycling relies on understanding the long-term relative contribution of its main actors; these include microbial sulfate reduction (MSR) and microbial sulfur disproportionation (MSD). However, a unifying theory is lacking for how MSR and MSD, with the same enzyme machinery and intimately linked evolutionary histories, perform two drastically different metabolisms. Here, we aim at shedding some light on the distribution, diversity, and evolutionary histories of MSR and MSD, with a focus on the Desulfobulbales as a test case. The Desulfobulbales is a diverse and widespread order of bacteria in the Desulfobacterota (formerly Deltaproteobacteria) phylum primarily composed of sulfate reducing bacteria. Recent culture- and sequence-based approaches have revealed an expanded diversity of organisms and metabolisms within this clade, including the presence of obligate and facultative sulfur disproportionators. Here, we present draft genomes of previously unsequenced species of Desulfobulbales, substantially expanding the available genomic diversity of this clade. We leverage this expanded genomic sampling to perform phylogenetic analyses, revealing an evolutionary history defined by vertical inheritance of sulfur metabolism genes with numerous convergent instances of transition from sulfate reduction to sulfur disproportionation.

scholarly journals Evaluating zinc isotope fractionation under sulfate reducing conditions using a flow-through cell and in situ XAS analysis

2017 ◽  
Vol 203 ◽  
pp. 1-14 ◽  
Author(s):  
Julia H. Jamieson-Hanes ◽  
Heather K. Shrimpton ◽  
Harish Veeramani ◽  
Carol J. Ptacek ◽  
Antonio Lanzirotti ◽  
...  
Keyword(s):  
Isotope Fractionation ◽  
Sulfate Reducing ◽  
Zinc Isotope ◽  
In Situ Xas ◽  
Reducing Conditions ◽  
Flow Through

Microbial Sulfate Reduction Enhances Arsenic Mobility Downstream of Zerovalent-Iron-Based Permeable Reactive Barrier

2016 ◽  
Vol 50 (14) ◽  
pp. 7610-7617 ◽  
Author(s):  
Naresh Kumar ◽  
Raoul-Marie Couture ◽  
Romain Millot ◽  
Fabienne Battaglia-Brunet ◽  
Jérôme Rose
Keyword(s):  
Sulfate Reduction ◽  
Permeable Reactive Barrier ◽  
Zerovalent Iron ◽  
Arsenic Mobility ◽  
Reactive Barrier ◽  
Microbial Sulfate Reduction ◽  
Iron Based

Arsenic Mobility during Flooding of Contaminated Soil: The Effect of Microbial Sulfate Reduction

2014 ◽  
Vol 48 (23) ◽  
pp. 13660-13667 ◽  
Author(s):  
Edward D. Burton ◽  
Scott G. Johnston ◽  
Benjamin D. Kocar
Keyword(s):  
Sulfate Reduction ◽  
Contaminated Soil ◽  
Arsenic Mobility ◽  
Microbial Sulfate Reduction

scholarly journals Inhibition of microbial sulfate reduction in a flow-through column system by (per)chlorate treatment

2014 ◽  
Vol 5 ◽  
Author(s):  
Anna Engelbrektson ◽  
Christopher G. Hubbard ◽  
Lauren M. Tom ◽  
Aaron Boussina ◽  
Yong T. Jin ◽  
...  
Keyword(s):  
Sulfate Reduction ◽  
Column System ◽  
Microbial Sulfate Reduction ◽  
Flow Through

scholarly journals U(VI) Reduction in Sulfate-Reducing Subsurface Sediments Amended with Ethanol or Acetate

2013 ◽  
Vol 79 (13) ◽  
pp. 4173-4177 ◽  
Author(s):  
Brandon J. Converse ◽  
Tao Wu ◽  
Robert H. Findlay ◽  
Eric E. Roden
Keyword(s):  
Sulfate Reduction ◽  
Electron Donor ◽  
National Laboratory ◽  
Oak Ridge ◽  
Sulfate Reducing ◽  
Reducing Conditions ◽  
Subsurface Sediments ◽  
Oak Ridge National Laboratory ◽  
Microbiological Analyses

ABSTRACTAn experiment was conducted with subsurface sediments from Oak Ridge National Laboratory to determine the potential for reduction of U(VI) under sulfate-reducing conditions with either ethanol or acetate as the electron donor. The results showed extensive U(VI) reduction in sediments supplied with either electron donor, where geochemical and microbiological analyses demonstrated active sulfate reduction.

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