Explain how nitrogen cycles in the earths system

The nitrogen cycle consists of 4 major steps:

When living organisms die on the earth surface or the seabed, their bodies decompose bringing the nitrogen into soil on land or into water in the ocean.  Special bacteria convert the nitrogen gas (N2 ) to ammonia (NH3) which the plants can use. This process is called Nitrogen fixation. After that a process called nitrification occurs in which some other types of bacteria are able to change nitrogen dissolved in waterways into a form that allows it to return to the atmosphere in the form of atmospheric nitrogen.