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A thiosulfate shunt in the sulfur cycle of marine sediments

Journal Article · · Science (Washington, D.C.); (USA)
The oxidation of sulfide, generated by bacterial sulfate reduction, is a key process in the biogeochemistry of marine sediments, yet the pathways and oxidants are poorly known. By the use of {sup 35}S-tracer studies of the S cycle in marine and freshwater sediments, a novel shunt function of thiosulfate (S{sub 2}O{sub 3}{sup 2{minus}}) was identified. The S{sub 2}O{sub 3}{sup 2{minus}} constituted 68 to 78% of the immediate HS{sup {minus}}-oxidation products and was concurrently reduced back to HS{sup {minus}}, oxidized to SO{sub 4}{sup 2{minus}}, and disproportionated to HS{sup {minus}} + SO{sub 4}{sup 2{minus}}. The small thiosulfate pool is thus involved in a dynamic HS{sup {minus}}-S{sub 2}O{sub 3}{sup 2{minus}} cycle in anoxic sediments. The disproportionation of thiosulfate may help account for the large difference in isotopic composition of sulfate and sulfides in sediments and sedimentary rocks.
OSTI ID:
6369636
Journal Information:
Science (Washington, D.C.); (USA), Journal Name: Science (Washington, D.C.); (USA) Vol. 249:4965; ISSN SCIEA; ISSN 0036-8075
Country of Publication:
United States
Language:
English