Why is air almost 80% nitrogen? Where does it all come from and do any life forms use it?

Question

Why is air almost 80% nitrogen? Where does it all come from and do any life forms use it?

In: 7

Answer 1

Nitrogen gas, N2, is an incredibly stable molecule. Nitrogen trapped in other molecules will tend towards forming N2 if it can, and N2 will tend to remain N2 unless something very reactive comes to change it.

So we get a whole bunch of this inert gas all around our planet and, besides diluting the oxygen and contributing to atmospheric pressure, it doesn’t do a huge amount.

Because it is so stable, it is useless as a fuel source, unlike oxygen. However, it is a wonderful source of nitrogen, and some bacteria and plants can ‘fix’ nitrogen from the air back into molecules. Once in molecules, it is a very important part of biological processes in every living creature.