Recent increases in anthropogenic N fixation in relation to “natural” N fixation. Modified from Vitousek, P. M. and P. A. Matson (1993). Agriculture, the global nitrogen cycle, and trace gas flux. The Biogeochemistry of Global Change: Radiative Trace Gases. R. S. Oremland. New York, Chapman and Hall: 193-208.
Nitrogen Mineralization (decay) Organic N NH 4 +
Nitrification NH 4 + NO 2 - NO 3 - Nitrosomonas Nitrobacter Aerobic Autotrophs Energy obtained?
Denitrification NO 3 - N 2 + N 2 O Denitrification is an anaerobic process that is carried out by denitrifying bacteria, which convert nitrate to dinitrogen (gas) in the following sequence: NO 3 - NO 2 - NO N 2 O N 2