Nitrogen Cycle

Percentage of atmosphere that nitrogen occupies

78%

Nitrogen fixation

bacteria convert N2 (atmospheric nitrogen) into NH3 (ammonia)

Nitrification

NH3 →NO2- (nitrite) → NO3- (nitrate)

Assimilation

plants root take up NH3, NH4+ (ammonium ion) and NO3- and convert into complex organic molecules

Ammonification

decomposers break down complex organisms into NH3 and NH4+

Dentrification

bacteria convert NH3 and NH4+ into NO2- and NO3- and then into N2 and N2O (nitrous oxide)