Biosensor determination of the microscale distribution of nitrate, nitrate assimilation, nitrification, and denitrification in a diatom-inhabited freshwater sediment
- Univ. of Aarhus (Denmark). Dept. of Microbial Ecology
High-resolution NO{sub 3}{sup {minus}} profiles in freshwater sediment covered with benthic diatoms were obtained with a new microscale NO{sub 3}{sup {minus}} biosensor characterized by absence of interference from chemical species other than NO{sub 2}{sup {minus}} and N{sub 2}O. Analysis of the microprofiles obtained indicated no nitrification during darkness, high rates of nitrification and a tight coupling between nitrification and denitrification during illumination, and substantial rates of NO{sub 3}{sup {minus}} assimilation during illumination. Nitrification during darkness could be induced by purging the bulk water with O{sub 2} gas, indicating that the stimulatory effect on nitrification by illumination was caused by algal production of O{sub 2}. NH{sub 4}{sup +} addition did not stimulate nitrification during darkness when O{sub 2} was restricted to the upper 1-mm layer, and there was thus a low nitrification potential in the permanently oxic top 1 mm of the sediment.
- OSTI ID:
- 658979
- Journal Information:
- Applied and Environmental Microbiology, Vol. 64, Issue 9; Other Information: PBD: Sep 1998
- Country of Publication:
- United States
- Language:
- English
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