What is the process of converting nitrates into nitrogen gas called?

The process of converting nitrates (NO3-) into nitrogen gas (N2) is known as denitrification. This microbial process occurs primarily in anaerobic conditions, such as in waterlogged soils or deep sediments. Denitrifying bacteria, such as Paracoccus denitrificans and Pseudomonas species, play a crucial role in this transformation. During denitrification, these bacteria use nitrates as an electron acceptor for their respiration, ultimately resulting in the release of nitrogen gas back into the atmosphere. This process is significant for the nitrogen cycle, as it helps to close the loop by returning atmospheric nitrogen to its gaseous form after being taken up by plants and converted into organic matter.

The other processes listed, such as ammonification and nitrification, involve different transformations within the nitrogen cycle. Ammonification converts organic nitrogen into ammonia, while nitrification involves the conversion of ammonia into nitrites and then nitrates. Fermentation, on the other hand, primarily relates to the breakdown of organic compounds in the absence of oxygen, which is distinct from the denitrification process. Understanding denitrification is vital for managing nitrogen levels in ecosystems and mitigating issues related to eutrophication and nitrogen pollution.