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.
Publication types
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Aerobiosis
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Anaerobiosis
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Arsenates / metabolism*
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Arsenites / metabolism*
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Bacteria, Anaerobic / classification
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Bacteria, Anaerobic / growth & development
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Bacteria, Anaerobic / isolation & purification*
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Bacteria, Anaerobic / metabolism*
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Bicarbonates / metabolism
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California
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Ecosystem
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Electron Transport
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Genes, rRNA
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Geologic Sediments / microbiology*
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Hydrogen-Ion Concentration
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Lactic Acid / metabolism
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Molecular Sequence Data
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Oxidation-Reduction
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Phylogeny
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Salts*
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Sodium Chloride
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Sulfides / metabolism
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Water / chemistry
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Water Microbiology*
Substances
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Arsenates
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Arsenites
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Bicarbonates
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Salts
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Sulfides
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Water
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Lactic Acid
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Sodium Chloride
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arsenite
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arsenic acid