bio

Denitrification

The chain of microbial reactions in oxygen-poor settings that returns nitrate to nitrogen gas, closing the loop that fixation opened. Without it, reactive nitrogen would accumulate indefinitely in soils and waters until ecosystems suffocated on their own fertility. The chain leaks at one intermediate step: some nitrogen escapes as N₂O, a potent greenhouse gas that also attacks the ozone layer — so the very mechanism that keeps the nitrogen cycle balanced is a serious emission source in modern agriculture.