During denitrification, nitrate is converted to which gas?

Denitrification is a crucial microbial process in the nitrogen cycle, where nitrate (NO3-) is converted into nitrogen gas (N2) or, in some cases, into nitrous oxide (N2O), which can then escape into the atmosphere. The primary pathway of denitrification involves a series of reductions where nitrate is first transformed into nitrite (NO2-), then to nitric oxide (NO), followed by nitrous oxide (N2O), and finally, completed with the formation of nitrogen gas (N2).

The conversion to nitrogen gas is vital for reducing nitrate levels in various environments, like soils and water systems, thus helping to mitigate issues related to nitrogen pollution, such as eutrophication in aquatic systems. By understanding this pathway and the products formed during denitrification, one can appreciate the role of microorganisms in maintaining ecological balance.

Other options represent different stages of nitrogen transformations but do not capture the final product of the denitrification process. Ammonium relates to ammonification rather than denitrification, nitrous oxide is an intermediate in denitrification, and carbon dioxide is a product of organic matter decomposition, not directly involved in the denitrification pathway. Understanding the complete cycle of nitrogen transformations is essential for