The Nitrogen Cycle

C. Doka

A. Greenberg

K. Guymon

Z. Reidy

Nitrogen Fixation

90% of fixation is done by bacteria

-Cyanobacteria converts the nitrogen into ammonia and ammonium

N2+ 3N2 -> 2NH3

Nitrification

If the ammonia is not used directly by the plant, aerobic bacteria can use oxygen to convert nitrogen to nitrite and further to nitrate

2NH3 + 3O2 - > 2NO2 + 2H+ + 2H2O2 NO2- + O2 -> 2NO3-

Ammonification

Dead plants and animals leave nitrogen which bacteria converts the nutrients back to ammonium and ammonia. Then the anaerobic bacteria can convert it to nitrogen gas through the process of denitrification.

NO3- + CH2O + H+ -> ½ N2O + CO2 + 1½ H2O

The atmosphere is the biggest reservoir of nitrogen

When plants are not able to nitrogen fixation they use assimilation to absorb the ammonium and nitrate

We as humans do not directly consume nitrogen. We have to consume plants or other plant consuming animals