Carbon Cycle

The Chemical Cycles

The Carbon Cycle
The Carbon Cycle describes the flow of carbon between living organisms and the non-living environment. Carbon cycles through the environment in the form of a gas, carbon dioxide (CO₂). The atmosphere of Earth contains .04 percent CO₂.

Illustration of the Carbon Cycle

Living organisms provide two important steps in the carbon cycle:

Plants absorb CO₂ from the atmosphere to use during photosynthesis.
Other organisms release CO₂ into the air during respiration.

In addition, there are several important non-organic storage areas of carbon in the environment:

A large portion of the Carbon on the Earth is stored in rocks.
The Earth's oceans hold a large amount of CO₂ because it easily dissolves in water.
Coal, oil, and limestone store carbon that once formed ancient organisms. Burning fossil fuels, like coal and oil, will release CO₂ into the atmosphere.