Nitrogen in the air
Nitrogen is required by all living organisms for the synthesis of proteins, nucleic acids and other nitrogen containing compounds. The Earth’s atmosphere contains almost 80 % nitrogen gas. It cannot be used in this form by most living organisms until it has been fixed, that is reduced (combined with hydrogen), to ammonia.
The nitrogen cycle is a series of processes that convert nitrogen gas to organic substances and back to nitrogen in nature. It is a continuous cycle that is maintained by the decomposers and nitrogen bacteria. The nitrogen cycle can be broken down into four types of reaction and micro-organisms play roles in all of these.
Where has that carbon atom been? The carbon cycle is a complex cyclical process through which all of the carbon atoms in existence rotate.
All living things depend on each other to live. Find out where microbes are in the food chain.