Oxidation of As(III) by the Bacterial Community of a Marine Sediment Monitored by Microcalorimetry

Abstract

Oxidation of arsenic(III) by the bacterial community of a contaminated sediment (from the Estaque marina, Marseille, France) was studied using microcalorimetry. A low, but reproducible, heat output was detectable during microbial As(III) oxidation. The heat produced was of the same order of magnitude as the heat value calculated from the standard molar enthalpy change for the As(III) oxidation by oxygen. Parameters associated with the biogeochemical cycles of arsenic, iron and carbon were studied in parallel. Amendment with arsenite delayed CO2 production and increased the rate of Fe(II) oxidation in the sediment. These results suggest a correlation between arsenic and iron biogeochemical cycles and mineralization of organic matter. Supplemental materials are available for this article. Go to the publisher's online edition of Geomicrobiology Journal to view the supplemental file.