Nitrification is the bacterial oxidation of ammonia (NH3) or ammonium (NH4+) to nitrate (NO3). It consists of two interconnected sub-processes: In the first step ammonia is oxidized to nitrite. In the second step, the nitrite is also converted to nitrate by oxidation. Both sub-processes provide the participating organisms with sufficient energy for their growth and other life processes. The nitrification plays a major role in the nitrogen cycle of ecosystems: it converts the ammonia released from dead biomass into nitrate – a nitrogenous mineral nutrient that is important for plants is created in this way.