What is Nitrogen Cycle?

The circulation of nitrogen through the living and non-living components of the biosphere is called nitrogen cycle. Nitrogen cycle maintain the percentage of nitrogen in the atmosphere more or less at a constant. This involves the biogeochemical transformation of N and N compounds. The major source of nitrogen is air, which is about 78% N_2 by volume.

The nitrogen cycle is the most complex of the cycles of elements that make up biological systems. This is due to the importance and prevalence of N in cellular metabolism, the diversity of types of nitrogen metabolism and the existence of the element in so many forms. Atmospheric nitrogen must first be broken apart before the nitrogen atoms can combine with other elements to form proteins and nucleic acids.

Steps involved in nitrogen cycle:

1. Nitrogen fixation — is the conversion of gaseous nitrogen to ammonia means nitrogen is fixed into a form that organisms can use.
2. Nitrification — is conversion of ammonia formed when water reacts with it to nitrate, soil bacteria performs nitrification with energy.
3. Assimilation — animals consume plant tissues they assimilate nitrogen by taking in plant nitrogen compounds and converting them to animal compounds.
4. Ammonification — is the conversion of biological nitrogen compounds into ammonia and ammonium ions. It begins when organisms produce nitrogen containing waste products like urea and uric acid.
5. Denitrification — denitrifying bacteria reverse the action of nitrogen fixing and nitrifying bacteria by returning nitrogen to the atmosphere.