Chapter 21.3, Problem 1CR

The principal form of nitrogen on Earth is N₂, which can be used as a N source only by nitrogen-fixing bacteria. Ammonia produced by nitrogen fixation or by ammonification can be assimilated into organic matter or oxidized to ${\text{NO}}_3{}^{-}$. Denitrification and anammox cause major losses of fixed nitrogen from the biosphere.

Q    Compare and contrast the processes of nitrification and denitrification in terms of the organisms involved, the environmental conditions that favor each process, and the changes in nutrient availability that accompany each process.