Which term describes the conversion of nitrate to nitrogen gas in the nitrogen cycle?

Denitrification is the term that refers to the conversion of nitrate (NO3-) into nitrogen gas (N2) in the nitrogen cycle. This process is crucial for returning nitrogen to the atmosphere, thus maintaining the balance of nitrogen within ecosystems. Denitrification is primarily carried out by specific bacteria that utilize nitrate as an electron acceptor in anaerobic conditions.

In this process, nitrates are reduced and ultimately released as nitrogen gas, which can escape into the atmosphere. This is important for preventing the accumulation of nitrates in soil and water, which can lead to problems such as water pollution and eutrophication.

Other terms, such as ammonification, nitrification, and immobilization, refer to different processes within the nitrogen cycle. Ammonification involves the conversion of organic nitrogen back to ammonia, nitrification is the oxidation of ammonia to nitrite and then nitrate, and immobilization is the process in which inorganic nitrogen is converted into organic forms by microbes or plants. Understanding these distinctions helps clarify the unique role of denitrification in the overall nitrogen cycle.