Denitrification in San Francisco Bay intertidal sediments

Applied and Environmental Microbiology
By: , and 

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Abstract

The acetylene block technique was employed to study denitrification in intertidal estuarine sediments. Addition of nitrate to sediment slurries stimulated denitrification. During the dry season, sediment-slurry denitrification rates displayed Michaelis-Menten kinetics, and ambient NO3 + NO2 concentrations (≤26 μM) were below the apparent Km (50 μM) for nitrate. During the rainy season, when ambient NO3 + NO2 concentrations were higher (37 to 89 μM), an accurate estimate of the Km could not be obtained. Endogenous denitrification activity was confined to the upper 3 cm of the sediment column. However, the addition of nitrate to deeper sediments demonstrated immediate N2O production, and potential activity existed at all depths sampled (the deepest was 15 cm). Loss of N2O in the presence of C2H2 was sometimes observed during these short-term sediment incubations. Experiments with sediment slurries and washed cell suspensions of a marine pseudomonad confirmed that this N2O loss was caused by incomplete blockage of N2O reductase by C2H2 at low nitrate concentrations. Areal estimates of denitrification (in the absence of added nitrate) ranged from 0.8 to 1.2 μmol of N2 m−2 h−1 (for undisturbed sediments) to 17 to 280 μmol of N2 m−2 h−1 (for shaken sediment slurries).

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Denitrification in San Francisco Bay intertidal sediments
Series title Applied and Environmental Microbiology
Volume 47
Issue 5
Year Published 1984
Language English
Publisher American Society for Microbiology
Contributing office(s) Pacific Regional Director's Office, San Francisco Bay-Delta
Description 7 p.
First page 1106
Last page 1112
Online Only (Y/N) N
Additional Online Files (Y/N) N