The process mainly due to the metabolism of a gas from anaerobic bacteria producing nitrogen gas that is released into the atmosphere is called?

• A. Nitrification
• B. Filtration
• C. Denitrification
• D. Anaerobics

Answer: (C)

Denitrification is the microbial process that uses nitrate as the terminal electron acceptor under low-oxygen conditions and reduces it all the way to nitrogen gas, which is released into the atmosphere. This happens in environments like sediments or waterlogged soils and completes a part of the nitrogen cycle by returning fixed nitrogen back to the air as N2. Nitrification is the aerobic conversion of ammonia to nitrate, which is the opposite direction in terms of oxygen use. Filtration is a physical/separation process, not a gas-producing microbial process. “Anaerobics” isn’t the standard term for this specific mechanism.