It is a part of the Nitrogen Cycle. The bacterias can convert ammonia into nitrite and nitrate, these compounds are fundamentally important for all life. They are used for the creation of proteins and amino acids.
Nitrification is the process by which bacteria will convert ammonia into nitrates! Keep in mind that this is only the middle step in the Nitrogen Cycle. First comes Fixation, then Nitrification, then Dentrification.
