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Denitrification in san francisco bay intertidal sediments.
R S Oremland1, C Umberger, C W Culbertson
1U.S. Geological Survey, Menlo Park, California 94025.
Applied and Environmental Microbiology
|May 1, 1984
Summary
Denitrification rates in estuarine sediments vary seasonally. Nitrate addition stimulates this process, but acetylene can interfere with measurements, especially at low nitrate levels.
Area of Science:
- Environmental Microbiology
- Estuarine Biogeochemistry
- Nitrogen Cycling
Background:
- Denitrification is a key microbial process in nitrogen cycling.
- Intertidal estuarine sediments are important sites for denitrification.
- Understanding denitrification is crucial for managing estuarine water quality.
Purpose of the Study:
- To investigate denitrification rates and kinetics in intertidal estuarine sediments.
- To assess the impact of seasonal variations on denitrification.
- To evaluate the effectiveness of the acetylene block technique.
Main Methods:
- Acetylene block technique for measuring denitrification.
- Sediment slurry incubations under varying conditions.
- Kinetic analysis using Michaelis-Menten models.
- Measurement of ambient nitrate and nitrite concentrations.
Main Results:
- Denitrification was stimulated by nitrate addition.
- Seasonal differences in ambient nitrate influenced kinetic measurements.
- Denitrification activity was present throughout the sediment profile, with higher rates in slurries.
- Observed N(2)O loss was attributed to incomplete acetylene blockage of N(2)O reductase at low nitrate concentrations.
Conclusions:
- Denitrification in intertidal sediments is influenced by nitrate availability and seasonal changes.
- The acetylene block technique requires careful consideration of conditions, particularly nitrate concentration.
- Estuarine sediments play a significant role in nitrogen removal, with potential activity extending to deeper layers.