Open AccessResponse of sediment microbial community structure in a freshwater reservoir to manipulations in oxygen availability
Author(s) -
Bryant Lee D.,
Little John C.,
Bürgmann Helmut
Publication year - 2012
Publication title -
fems microbiology ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.377
H-Index - 155
eISSN - 1574-6941
pISSN - 0168-6496
DOI - 10.1111/j.1574-6941.2011.01290.x
Subject(s) - biogeochemical cycle , hypolimnion , sediment , biology , biomass (ecology) , environmental chemistry , abiotic component , microbial population biology , ecology , oxygen , anoxic waters , bacteria , chemistry , nutrient , eutrophication , paleontology , genetics , organic chemistry
Hypolimnetic oxygenation systems ( HO x) are being increasingly used in freshwater reservoirs to elevate dissolved oxygen levels in the hypolimnion and suppress sediment–water fluxes of soluble metals (e.g. F e and M n) which are often microbially mediated. We assessed changes in sediment microbial community structure and corresponding biogeochemical cycling on a reservoir‐wide scale as a function of HO x operations. Sediment microbial biomass as quantified by DNA concentration was increased in regions most influenced by the HO x. Following an initial decrease in biomass in the upper sediment while oxygen concentrations were low, biomass typically increased at all depths as the 4‐month‐long oxygenation season progressed. A distinct shift in microbial community structure was only observed at the end of the season in the upper sediment near the HO x. While this shift was correlated to HO x‐enhanced oxygen availability, increased TOC levels and precipitation of F e‐ and M n‐oxides, abiotic controls on F e and M n cycling, and/or the adaptability of many bacteria to variations in prevailing electron acceptors may explain the delayed response and the comparatively limited changes at other locations. While the sediment microbial community proved remarkably resistant to relatively short‐term changes in HO x operations, HO x‐induced variation in microbial structure, biomass, and activity was observed after a full season of oxygenation.