VAAM-Jahrestagung 2011 Karlsruhe, 3.–6. April 2011

AMP035Diversity and Distribution of Fe(II)-oxidizing and Fe(III)-reducing microorganisms in salt lake sediments ofSouthern RussiaM. Emmerich*, S. Behrens, A. KapplerDepartment of Geomicrobiology, Center for Applied Geosciences,Tübingen, GermanyHypersaline environments challenge their inhabiting (micro)fauna with theirextreme hyperosmolaric conditions. These conditions result in the commonobservation that the metabolic diversity decreases with increasing salinity.Nonetheless, various microbial metabolisms have been found to occur athigh salt concentration [1]. Currently, information about microbial Fe(III)and Fe(II) metabolism in hypersaline environments is very scarce. Westudied Fe(II)-oxidizing and Fe(III)-reducing bacteria and archaea in fivedifferent salt lake sediments from the Kalmykien Steppe in Russia with acombination of culture-dependent and -independent techniques. Our goalswere 1) to identify and quantify anaerobic Fe(II)-oxidizing and Fe(III)-reducing microorganisms in the salt lake sediments and 2) to measure up towhich salinities microbial Fe(II) oxidation and Fe(III) reduction can bedetected.Results from enrichment and isolation experiments showed that Fe(III)-reducers were active and growing even at 5 M salinity while Fe(II)-oxidizing cultures only remained active for several transfers on 0.5 M NaCl.Results from most probable number (MPN) counts and quantitative PCR(qPCR) revealed that culturable Fe(III)-reducers and anaerobic Fe(II)-oxidizers represent