series of flows in an ecosystem which move nitrogen between various stores and allow it to perform functions essential for life. At its simplest level, nitrogen in the form of nitrates is taken in by plant roots and built into proteins which then enter herbivores. Excretion and decay then return the nitrogen to the soil as ammonia, which is converted back to nitrate by bacteria.
Geography Dictionary & Glossary for Students \\ ITS Tutorial School (ITS) - Hong Kong.