Measurement of nitrous oxide reductase activity in aquatic sediments
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Abstract
Denitrification in aquatic sediments was measured by an N2O reductase assay. Sediments consumed small added quantities of N2O over short periods (a few hours). In experiments with sediment slurries, N2O reductase activity was inhibited by O2, C2H2, heat treatment, and by high levels of nitrate (1 mM) or sulfide (10 mM). However, ambient levels of nitrate (<100 μM) did not influence activity, and moderate levels (about 150 μM) induced only a short lag before reductase activity began. Moderate levels of sulfide (<1 mM) had no effect on N2O reductase activity. Nitrous oxide reductase displayed Michaelis-Menten kinetics in sediments from freshwater (Km = 2.17 μM), estuarine (Km = 14.5 μM), and alkaline-saline (Km = 501 μM) environments. An in situ assay was devised in which a solution of N2O was injected into sealed glass cores containing intact sediment. Two estimates of net rates of denitrification in San Francisco Bay under approximated in situ conditions were 0.009 and 0.041 mmol of N2O per m2 per h. Addition of chlorate to inhibit denitrification in these intact-core experiments (to estimate gross rates of N2O consumption) resulted in approximately a 14% upward revision of estimates of net rates. These results were comparable to an in situ estimate of 0.022 mmol of N2O per m2 per h made with the acetylene block assay.
Study Area
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | Measurement of nitrous oxide reductase activity in aquatic sediments |
| Series title | Applied and Environmental Microbiology |
| DOI | 10.1128/aem.51.1.18-24.1986 |
| Volume | 51 |
| Issue | 1 |
| Year Published | 1986 |
| Language | English |
| Publisher | American Society for Microbiology |
| Contributing office(s) | San Francisco Bay-Delta, Toxic Substances Hydrology Program, Pacific Regional Director's Office |
| Description | 7 p. |
| First page | 18 |
| Last page | 24 |
| Country | United States |
| State | California |
| Other Geospatial | San Francisco Bay |
| Online Only (Y/N) | N |
| Additional Online Files (Y/N) | N |
| Google Analytic Metrics | Metrics page |