Microbiology: A microbial arsenic cycle in a salt-saturated, extreme environment

R.S. Oremland; T.R. Kulp; J.S. Blum; S.E. Hoeft; S. Baesman; L.G. Miller; J.F. Stolz

doi:10.1126/science.1110832

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Microbiology: A microbial arsenic cycle in a salt-saturated, extreme environment

R.S. Oremland·T.R. Kulp·J.S. Blum·S.E. Hoeft·S. Baesman·L.G. Miller·J.F. Stolz

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Abstract

Searles Lake is a salt-saturated, alkaline brine unusually rich in the toxic element arsenic. Arsenic speciation changed from arsenate [As(V)] to arsenite [As(III)] with sediment depth. Incubated anoxic sediment slurries displayed dissimilatory As(V)-reductase activity that was markedly stimulated by H2 or sulfide, whereas aerobic slurries had rapid As(III)-oxidase activity. An anaerobic, extremely haloalkaliphilic bacterium was isolated from the sediment that grew via As(V) respiration, using either lactate or sulfide as its electron donor. Hence, a full biogeochemical cycle of arsenic occurs in Searles Lake, driven in part by inorganic electron donors.

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R.S. Oremland, T.R. Kulp, J.S. Blum, S.E. Hoeft, S. Baesman, L.G. Miller, J.F. Stolz. 2005. Microbiology: A microbial arsenic cycle in a salt-saturated, extreme environment. https://doi.org/10.1126/science.1110832

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