ABSTRACT
Nitrogen is a fairly inert gas. About 78% of the air we breathe is nitrogen. A variety of algae, bacteria, and fungi can "fix" inert nitrogen gas into chemicals that they can use (or that organisms that associate with them or feed on them can use) to manufacture their proteins. When an organism dies, the nitrogen in its decomposing protein is released to the environment in various chemical forms, including nitrogen gas. The sum of processes involving fixation and release of nitrogen gas is called the "nitrogen cycle." Detailed descriptions of cycle processes can be found elsewhere.1
