water - carbon - nitrogen
The carbon cycle, however, can occur upon different triggers. Though, we will only cover one. Dead organisms and animal waste break down into mineral carbon (or "Fossil Fuels"), which buries itself beneath the soil. Upon being burnt, gaseous carbon dioxide is released into the atmosphere.
A type of bacteria called nitrogen fixing bacteria take in atmospheric nitrogen and produce ammonia (NH3). Other bacteria use this ammonia to produce nitrates and nitrites. These are used by plants to make amino acids which are then used to make plant proteins. Plants are consumed by other organisms which use the plant amino acids to make their own.
Decomposers convert the nitrogen found in other organisms into ammonia and return it to the soil. A few of these type of bacteria return nitrogen to the atmosphere by a process called denitrification, however this amount is little.