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Factors regulating nitrification in aquatic sediments: Effects of organic carbon, nitrogen availability, and pH

Canadian Journal of Fisheries and Aquatic Sciences

By:
, ,
DOI: 10.1139/f02-032

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Abstract

We investigated the response in nitrification to organic carbon (C) availability, the interactive effects of the C: nitrogen (N) ratio and organic N availability, and differing pH in sediments from several streams in the upper midwestern United States. In addition, we surveyed 36 streams to assess variability in sediment nitrification rates. Labile dissolved organic carbon (DOC) additions of 30 mg C??L-1 (as acetate) to stream sediments reduced nitrification rates (P < 0.003), but lower concentration additions or dilution of ambient DOC concentration had no effect on nitrification. C:N and organic N availability strongly interacted to affect nitrification (P < 0.0001), with N availability increasing nitrification most at lower C:N. Nitrification was also strongly influenced by pH (P < 0.002), with maximum rates occurring at pH 7.5. A multiple regression model developed from the stream survey consisted of five variables (stream temperature, pH, conductivity, DOC concentration, and total extractable NH4+) and explained 60% of the variation observed in nitrification. Our results suggest that nitrification is regulated by several variables, with NH4+ availability and pH being the most important. Organic C is likely important at regulating nitrification only under high environmental C:N conditions and if most available C is relatively labile.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Factors regulating nitrification in aquatic sediments: Effects of organic carbon, nitrogen availability, and pH
Series title:
Canadian Journal of Fisheries and Aquatic Sciences
DOI:
10.1139/f02-032
Volume
59
Issue:
3
Year Published:
2002
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
554
Last page:
563
Number of Pages:
10