The Nitrogen Cycle

1
The Nitrogen Cycle

• C. Doka
• A. Greenberg
• K. Guymon
• Z. Reidy

2
Nitrogen Fixation
90 of fixation is done by bacteria -Cyanobacteria
converts the nitrogen into ammonia and
ammonium N2 3N2 -gt 2NH3
3
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 - gt 2NO2 2H 2H2O2 NO2- O2 -gt
2NO3-
4
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 -gt ½ N2O CO2 1½ H2O
5
When plants are not able to nitrogen fixation
they use assimilation to absorb the ammonium and
nitrate
The atmosphere is the biggest reservoir of
nitrogen
We as humans do not directly consume nitrogen. We
have to consume plants or other plant consuming
animals