How do bacteria contribute to the nitrogen cycle?

Bacteria play a crucial role in the nitrogen cycle by converting nitrogen into various forms that plants and animals can use.

Bacteria are the primary drivers of the nitrogen cycle, a process that is essential for life on Earth. Nitrogen is a vital component of amino acids, proteins, and DNA, but the majority of nitrogen on Earth is in the form of nitrogen gas (N2), which most organisms cannot use. Bacteria, however, have the unique ability to convert nitrogen gas into forms that other organisms can utilise.

There are several types of bacteria involved in the nitrogen cycle. Nitrogen-fixing bacteria, found in the soil and in the root nodules of leguminous plants, convert nitrogen gas into ammonia (NH3) in a process called nitrogen fixation. This ammonia is then converted into nitrites (NO2-) and nitrates (NO3-) by nitrifying bacteria. These nitrates can be absorbed by plants and used to make proteins.

Denitrifying bacteria, on the other hand, convert nitrates back into nitrogen gas, which is released back into the atmosphere. This process, known as denitrification, helps to complete the nitrogen cycle.

In addition to these, there are also bacteria that facilitate the process of ammonification. When plants and animals die, decomposer bacteria break down the proteins in their bodies into ammonia, which can then be converted into nitrites and nitrates by nitrifying bacteria.

In summary, bacteria are essential in the nitrogen cycle as they facilitate the conversion of nitrogen into various forms that can be used by plants and animals. Without these bacteria, the nitrogen in the atmosphere would remain inaccessible to most life forms, disrupting the balance of the ecosystem.