2.The Nitrogen Cycle氮循环 Nitrification NO2 Oxidation reactions Assimilation NH2 groups Assimilation of protein Nitrogen NO3 fixation are represented DRNA mmonification Oxic by yellow NH3 Anoxic arrows and NH2 groups Assimilation reductions NO2 of protein Ammonification Nitrogen in red. fixation NO, N20 Anammox N2 5 Denitrification 2012 Pearson Education,Inc.5 Microbiology, Shanghai Jiao Tong University 2. The Nitrogen Cycle氮循环 Oxidation reactions are represented by yellow arrows and reductions in red