Influence of Phosphorus and Cell Geometry on the Fractionation of Sulfur Isotopes by Several Species of Desulfovibrio during Microbial Sulfate Reduction
Author(s)
Zaarur, Shikma; Wang, David T.; Ono, Shuhei; Bosak, Tanja
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We investigated the influence of organic substrates and phosphate concentration on the rates of dissimilatory microbial sulfate reduction and the 34 S/ 32 S isotopic fractionation produced by several Desulfovibrio species. Our experiments corroborate the previously reported species-specific correlation between sulfur isotope fractionation and cell-specific sulfate reduction rates. We also identify cell size as a key factor that contributes to the species-effect of this correlation. Phosphate limitation results in larger cells and contributes to a small decrease in sulfur isotope fractionation concomitant with an apparent increase in cell-specific sulfate reduction rates. Sulfur isotope fractionation in phosphate-limited cultures asymptotically approaches a lower limit of approximately 5% as cell-specific sulfate reduction rates increase to < 100 fmol cell -1 day -1 . These experimental results test models that link the reversibilities of enzymatic steps in dissimilatory sulfate reduction to sulfur isotope fractionation and show that these models can provide consistent predictions across large variations in physiological states experienced by sulfate reducing bacteria.
Date issued
2017-05Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary SciencesJournal
Frontiers in Microbiology
Publisher
Frontiers Research Foundation
Citation
Zaarur, Shikma et al. “Influence of Phosphorus and Cell Geometry on the Fractionation of Sulfur Isotopes by Several Species of Desulfovibrio During Microbial Sulfate Reduction.” Frontiers in Microbiology 8 (May 2017): 890 © 2017 Zaarur, Wang, Ono and Bosak
Version: Final published version
ISSN
1664-302X