Isotope fractionation by sulfate-reducing natural populations and the isotopic composition of sulfide in marine sediments

Research Article| June 01, 2001 Isotope fractionation by sulfate-reducing natural populations and the isotopic composition of sulfide in marine sediments Kirsten S. Habicht; Kirsten S. Habicht 1Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany, and Danish Center for Earth System Science (DCESS), Institute of Biology, University of Southern Denmark, Odense University, Campusvej 55, 5230 Odense M, Denmark Search for other works by this author on: GSW Google Scholar Donald E. Canfield Donald E. Canfield 2Danish Center for Earth System Science (DCESS), Institute of Biology, University of Southern Denmark, Odense University, Campusvej 55, 5230 Odense M, Denmark Search for other works by this author on: GSW Google Scholar Geology (2001) 29 (6): 555–558. https://doi.org/10.1130/0091-7613(2001)029<0555:IFBSRN>2.0.CO;2 Article history received: 30 Oct 2000 rev-recd: 26 Feb 2001 accepted: 03 Mar 2001 first online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Kirsten S. Habicht, Donald E. Canfield; Isotope fractionation by sulfate-reducing natural populations and the isotopic composition of sulfide in marine sediments. Geology 2001;; 29 (6): 555–558. doi: https://doi.org/10.1130/0091-7613(2001)029<0555:IFBSRN>2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Isotope fractionations during sulfate reduction by natural bacterial populations were measured in seven different marine sediments and compared with the isotopic composition of solid-phase sulfides in the same sediments. The measured fractionations during sulfate reduction could explain only between 41% and 85% of the 34S depletion in the sedimentary sulfides. This result directly demonstrates that the depletion of 34S in solid sulfides is an expression of the combined activity of sulfate-reducing organisms with additional fractionations accumulated during the oxidative part of the sulfur cycle. The only known process to significantly augment the fractionations created during sulfate reduction is the microbial disproportionation of the intermediate sulfur compounds: elemental sulfur, thiosulfate, and sulfite. In a simple model, we show how important each of these disproportionation processes could be in generating the isotopic composition of sedimentary sulfides. The sulfate reduction rates in the sediments studied varied by a factor of 1000 and did not correlate with the fractionation during sulfate reduction. By contrast, a correlation was observed between sulfate- reduction rate and the extent of 34S depletion into sedimentary sulfides, the most 34S-depleted sulfides found in sediments supporting the lowest rates of sulfate reduction. Thus, the fractionations imposed during the disproportionating processes are better expressed in sediments with low sulfate-reduction rates. The direct phototrophic oxidation of sulfide to sulfate, with minimal fractionation, may have been important in the sediments that had a high sulfate-reduction rate. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.