Question

Which organisms play a role in nitrogen fixation and denitrification?

Answer 1

Leguminous plants have root nodules in which there is rhizobium, bacteria which fixes nitrogen to the soil for the plant.

Answer 2

These organisms convert nitrogen in the soil to ammonia, which can then be taken up by plants. This process also occurs in aquatic ecosystems, where cyanobacteria participate. After nitrogen has been fixed, other bacteria convert it into nitrate, in a process known as nitrification.