Phylogenetic and physiological diversity of dissimilatory ferric iron reducers in sediments of the polluted Scheldt Estuary, northwest Europe
Lin, B.; Hyacinthe, C.; Bonneville, S.; Braster, M.; Van Cappellen, P.; Roling, W.F.M. (2007). Phylogenetic and physiological diversity of dissimilatory ferric iron reducers in sediments of the polluted Scheldt Estuary, northwest Europe. Environ. Microbiol. 9(8): 1956-1968. dx.doi.org/10.1111/j.1462-2920.2007.01312.x In: Environmental Microbiology. Blackwell Scientific Publishers: Oxford. ISSN 1462-2912; e-ISSN 1462-2920, more |  |
| Keywords | Phylogenetics
Brackish water; Fresh water |
| Authors | | Top | - Lin, B., more
- Hyacinthe, C.
- Bonneville, S.
| - Braster, M.
- Van Cappellen, P., more
- Roling, W.F.M.
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| Abstract | The potential for dissimilatory ferric iron [Fe(III)] reduction in intertidal sediments of the polluted Scheldt estuary, Northwest Europe, was assessed by combining field-based geochemical measurements with laboratory experiments on the associated microbiology. Microbial communities at a freshwater and brackish location were characterized by culture-independent 16S rRNA gene analysis, as well as enrichments, strain isolation and physiological screening. Dilution-to-extinction batch enrichments using a variety of Fe(III) sources were performed. The dilution factor of the inoculum in the enrichments had a more determining effect on the Fe(III)-reducing microbial community structure than the Fe(III) source. Well-known Fe(III) reducers, including members of the family Geobacteraceae and the genus Shewanella, constituted only a small fraction (= 1%) of the in situ microbial community. Instead, facultative anaerobic Ralstonia and strictly anaerobic, spore-forming Clostridium species dominated Fe(III) reduction. These species were able to utilize a variety of electron acceptors. This flexibility may help the organisms to survive in the dynamic estuarine environment. The high diversity and abundance of culturable Fe(III) reducers (4.6 × 105 and 2.4 × 104 cells g-1 sediment at the freshwater and brackish site respectively), plus the high concentrations of chemically reducible solid-phase Fe(III) at the sites, implied a high potential for dissimilatory Fe(III) reduction in the estuarine sediments. Pore water chemical data further supported in situ dissimilatory Fe(III) reduction. |
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