Seawater sulfate reduction and sulfur isotope fractionation in basaltic systems: Interaction of seawater with fayalite and magnetite at 200–350°C

Growth of Saccharomyces cerevisiae in minimal salts – glucose – SO42− medium with varying concentrations of pantothenate (0–1000 μg/L) produced changes in the cellular lipid content and in the ratio of saturated to unsaturated fatty acids. Substantial differences in SO42−diffusion were also observed with changes in pantothenate concentration. During sulfate reduction, the δ34S value of the evolved sulfide varied with the pantothenate concentration ranging from −31‰ in the absence of pantothenate to 0‰ at 400−1000 μg/L pantothenate. The isotope selectivity is related to the effect of pantothenate concentration on cellular metabolism.

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Diversity of Sulfur Isotope Fractionations by Sulfate-Reducing Prokaryotes

Applied and Environmental Microbiology ◽

10.1128/aem.67.2.888-894.2001 ◽

2001 ◽

Vol 67 (2) ◽

pp. 888-894 ◽

Cited By ~ 257

Author(s):

Jan Detmers ◽

Volker Brüchert ◽

Kirsten S. Habicht ◽

Jan Kuever

Keyword(s):

Sulfate Reduction ◽

Isotope Fractionation ◽

Sulfur Isotope ◽

Reduction Rate ◽

Sulfate Reduction Rate ◽

Dissimilatory Sulfate Reduction ◽

Systematic Effect ◽

Sulfate Reducers ◽

Sulfate Reducing ◽

Sulfur Isotope Fractionation

ABSTRACT Batch culture experiments were performed with 32 different sulfate-reducing prokaryotes to explore the diversity in sulfur isotope fractionation during dissimilatory sulfate reduction by pure cultures. The selected strains reflect the phylogenetic and physiologic diversity of presently known sulfate reducers and cover a broad range of natural marine and freshwater habitats. Experimental conditions were designed to achieve optimum growth conditions with respect to electron donors, salinity, temperature, and pH. Under these optimized conditions, experimental fractionation factors ranged from 2.0 to 42.0‰. Salinity, incubation temperature, pH, and phylogeny had no systematic effect on the sulfur isotope fractionation. There was no correlation between isotope fractionation and sulfate reduction rate. The type of dissimilatory bisulfite reductase also had no effect on fractionation. Sulfate reducers that oxidized the carbon source completely to CO2 showed greater fractionations than sulfate reducers that released acetate as the final product of carbon oxidation. Different metabolic pathways and variable regulation of sulfate transport across the cell membrane all potentially affect isotope fractionation. Previous models that explained fractionation only in terms of sulfate reduction rates appear to be oversimplified. The species-specific physiology of each sulfate reducer thus needs to be taken into account to understand the regulation of sulfur isotope fractionation during dissimilatory sulfate reduction.

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Primary productivity, sulfate reduction and sulfur isotope fractionation in algal mats and sediments of Hamelin Pool, Shark Bay, W.A.

Deep Sea Research Part B Oceanographic Literature Review ◽

10.1016/0198-0254(80)96069-0 ◽

1980 ◽

Vol 27 (12) ◽

pp. 896

Keyword(s):

Sulfate Reduction ◽

Primary Productivity ◽

Isotope Fractionation ◽

Sulfur Isotope ◽

Algal Mats ◽

Shark Bay ◽

Sulfur Isotope Fractionation

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Patterns of sulfur isotope fractionation during microbial sulfate reduction

Geobiology ◽

10.1111/gbi.12149 ◽

2015 ◽

Vol 14 (1) ◽

pp. 91-101 ◽

Cited By ~ 78

Author(s):

A. S. Bradley ◽

W. D. Leavitt ◽

M. Schmidt ◽

A. H. Knoll ◽

P. R. Girguis ◽

...

Keyword(s):

Sulfate Reduction ◽

Isotope Fractionation ◽

Sulfur Isotope ◽

Microbial Sulfate Reduction ◽

Sulfur Isotope Fractionation

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

Applied and Environmental Microbiology ◽

10.1128/aem.01842-12 ◽

2012 ◽

Vol 78 (23) ◽

pp. 8368-8376 ◽

Cited By ~ 33

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.

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