Nitrogen Cycle

Ammonia that is not taken up by plants may undergo nitrification. In this process, specialized soil bacteria such as the Rhizobium bactera convert most of the NH3, and NH4+ in the soil to nitrate ions (NO3-), which are easily taken up by the roots of plants. The plants then use these forms of nitrogen to produce various amino acids, proteins, nucleic acids, and vitamins. Animals that eat plants eventually consume these nitrogen containing compounds, as do detritus feeders and decomposers.