Nitrogen is a nutrient. It's found in living things like plants and animals. Nitrogen is very important because it has DNA, RNA, and proteins. Nitrogen is the gas in the atmosphere, about 80% of nitrogen in air. Plants and animals are dependent on specific bacteria that can change the nitrogen in the nitrogen.
Phase One:
Nitrogen fixation: Unavailable nitrogen is converted into ammonia by nitrogen fixing bacteria. The ammonia combines with water to make ammonium ion. Ammonium ion is readily assimilated by plants. The bacteria that fixed nitrogen lives in certain plant roots. This step involves the biosphere, atmosphere, hydrosphere, and geosphere.
Phase Two:
Assimilation is the biologically available nitrogen. Plants are eaten by animals and animals take the nitrogen from the plants. This step is called assimilation and involves the biosphere and geosphere. This part of the nitrogen cycle can also involve humans. The nitrogen in plants, which animals eat, can also be eaten by humans, transferring the nitrogen into phase 3.
Phase Three:
Animal waste and tissue remains of dead plants and animals are decomposed by bacteria and fungi, which turned the organic nitrogen back into ammonium ion.This part of the cycle is called ammonification and is only in the biosphere.
Phase Four:
Ammonium ion is then converted into nitrate by nitrifying bacteria. This step is called nitrification and is in the biosphere.
Phase Five:
Some of this nitrate is back into dinitrogen by the nitrifying bacteria which completes the nitrogen cycle. The remaining nitrate can be taken up by organisms such as plants. This final step is in the biosphere and atmosphere.
