What is denitrification and where does it occur?

Denitrification is a microbial process that converts nitrates in soil or water back into nitrogen gas.

Denitrification is a crucial part of the nitrogen cycle, which is a biological process that makes nitrogen available to living organisms and then returns it back to the atmosphere. This process is carried out by a variety of microorganisms, including bacteria and fungi, which are found in soil and water environments.

The process begins when nitrates, which are a form of nitrogen that plants can absorb and use, are converted into nitrites by bacteria. These nitrites are then further reduced to nitrogen gas, which is released back into the atmosphere. This is the opposite of nitrogen fixation, where nitrogen gas is converted into nitrates by bacteria.

Denitrification primarily occurs in environments where oxygen is limited, such as waterlogged soils or the bottom of lakes and oceans. This is because the bacteria that carry out denitrification are anaerobic, meaning they can survive in environments without oxygen.

In agricultural settings, denitrification can lead to the loss of nitrogen from the soil, which can reduce soil fertility and crop yields. However, it also plays a crucial role in reducing the amount of nitrate pollution in water bodies, which can cause problems such as algal blooms and 'dead zones' where nothing can live.

In summary, denitrification is a vital process in the nitrogen cycle, carried out by microorganisms in soil and water environments, converting nitrates back into nitrogen gas.