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Factors affecting nitrification in situ in a heated stream
Applied and Environmental Microbiology
|April 1, 1977
Summary
Nitrification occurs in streams only when temperatures exceed 28°C. Ammonium oxidation rates are higher than nitrite oxidation, leading to nitrite accumulation, especially in warmer months.
Area of Science:
- Environmental microbiology
- Aquatic chemistry
Background:
- Nitrification is a key microbial process in nitrogen cycling.
- Previous studies indicated nitrification in the studied stream.
Purpose of the Study:
- To investigate the conditions affecting nitrification in a stream.
- To quantify ammonium and nitrite oxidation rates.
- To understand factors influencing nitrification dynamics.
Main Methods:
- Measuring nitrification rates at different temperatures.
- Quantifying ammonium and nitrite oxidizer populations.
- Assessing ammonium and nitrite oxidation rates.
- Monitoring dissolved oxygen and temperature.
Main Results:
- Nitrification was significant above 28°C and negligible below 17°C.
- Ammonium oxidizers outnumbered nitrite oxidizers significantly (43:1 to 1,113:1).
- Ammonium oxidation rate (0.50 mg NH4-N/L/h) exceeded nitrite oxidation rate (0.29 mg NO2-N/L/h), causing nitrite accumulation.
- Nitrification rates increased with dissolved oxygen and were highest in summer.
Conclusions:
- Stream nitrification is highly temperature-dependent.
- Dominance of ammonium oxidizers and higher ammonium oxidation rates lead to nitrite accumulation.
- Dissolved oxygen and seasonal variations influence nitrification rates.