Steps of the Nitrogen Cycle

Nitrogen fixation

1. conversion of atmospheric nitrogen into ammonia, performed by bacteria in the roots of legumes or lightning. N2 --> NH3

Nitrification

2. conversion of ammonia to nitrite to nitrate performed by bacteria. NH3 --> NO2 --> NO3-

Assimilation

3. inorganic nitrogen is uptaken by the roots of plants and becomes part of the food chain. NO3- --> organic nitrogen (proteins and nucleic acids)

Ammonification

4. conversion of organic nitrogen into ammonia. Performed by decomposers (bacteria, fungus) to return nitrogen to the soil. Organic nitrogen --> NH3

Dentrification

5. nitrates are returned to the atmosphere by anaerobic bacteria. NO3- --> N2

1.Nitrogen Fixation
2. Nitrification
3. Assimilation
4. Ammonification
5. Denitrification

Nitrogen Cycle Steps in Order