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Updated: Sep 7, 2026

The Benthic Exchange of O2, N2 and Dissolved Nutrients Using Small Core Incubations
Published on: August 3, 2016
In situ distribution and activity of nitrifying bacteria in freshwater sediment
Dörte Altmann1, Peter Stief, Rudolf Amann
1Max Planck Institute for Marine Microbiology, D-28359 Bremen, Germany.
Abstract:
Nitrification was investigated in a model freshwater sediment by the combined use of microsensors and fluorescence in situ hybridization with rRNA-targeted oligonucleotide probes. In situ nitrification activity was restricted mainly to the upper 2 mm of the sediment and coincided with the maximum abundance of nitrifying bacteria, i.e. 1.5 x 107 cells cm-3 for ammonia-oxidizing Beta-proteobacteria (AOB) and 8.6 x 107 cells cm-3 for Nitrospira-like nitrite-oxidizing bacteria (NOB). Cell numbers of AOB decreased more rapidly with depth than numbers of NOB. For the first time, Nitrospira-like bacteria could be quantified and correlated with in situ nitrite oxidation rates in a sediment. Estimated cell-specific nitrite oxidation rates were 1.2-2.7 fmol NO2- cell-1 h-1.
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