GEOC 138 |
| Kristina L. Straub, Fakultät für Biologie, Fakultät für Biologie, Universität Konstanz, 78457 Konstanz, Germany |
| Three different strains (BrG1, BrG2, and BrG3) of ferrous iron-oxidizing, nitrate-reducing bacteria were isolated from freshwater sediments. All three strains were facultative anaerobes and utilized a variety of organic substrates or molecular hydrogen with nitrate as electron acceptor. Analyses of 16S rDNA sequences showed that strain BrG1 was affiliated with the genus Acidovorax, strain BrG2 was a representative of the genus Aquabacterium, and strain BrG3 was related to the genus Thermomonas. Bacteria similar to these three strains were detected with molecular techniques in different sediments. Further molecular analyses of cultures from most-probable-number dilutions indicate that the ability to oxidize ferrous iron with nitrate seems to be widespread amongst the Proteobacteria. In co-cultures of iron-oxidizing and iron-reducing bacteria an anaerobic cycling of iron was shown, indicating that iron can be cycled between its oxidation states +II and +III by microbial activities in anoxic zones of sediments. |
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Microbially Mediated Manganese and Iron Oxidation in the Biosphere
8:00 AM-12:15 PM, Wednesday, March 31, 2004 Marriott -- Marquis NE, Oral
Division of Geochemistry |