title: Measurement of denitrification in two freshwater sediments by an in situ acetylene inhibition method.
abstract: An acetylene inhibition method was satisfactorily used for the in situ measurement of denitrification in two sediment-water systems incubated for not more than 22 h. In the presence of added nitrate, denitrification acted as a source of nitrous oxide in a drainage pond, but acted as a sink in its absence. The averaged rates of nitrous oxide accumulation with nitrate enrichment in the absence and presence of acetylene were 0.15 and 0.30 mg of N mh, respectively. Acetylene reduction at an average rate of 0.07 mmol of C(2)H(4) formed mh was simultaneously measured in the absence of added nitrate. In a small eutrophic lake where nitrogen was nonlimiting, the in situ rates of sediment denitrification were 0.09 and 0.11 mg of N mh in the presence and absence of macrophytes, respectively, and no acetylene reduction activity was found.
authors.affiliation: Department of Microbiology, Macdonald Campus of McGill University, Ste Anne de Bellevue, Québec, Canada H9X 1C0.
authors.forename: Y K
authors.initials: YK
authors.lastname: Chan
authors.forename: R
authors.initials: R
authors.lastname: Knowles