Carbon is Absorbed by Plants
Plants absorb carbon (C), in the form of carbon dioxide (`~CO_2` ), into their cells from the atmosphere.
The plants then use the absorbed `~CO_2` in the chemical process of photosynthesis. During photosynthesis, plants use energy from the sun and combine `~CO_2` with water to form sugar (`~CH_2O` ) and oxygen (`~O_2` ), as shown in the reaction below:
`~CO_2 + ~H_2O + ` energy `-gt ~CH_2O + ~O_2`
Carbon is Released by Plants
Plants return carbon to the atmosphere in the form of carbon dioxide (`~CO_2)` . This can occur four ways:
- Plants break down the sugar for energy and release carbon dioxide.
- Animals eat plants, break down the sugar for energy, and release carbon dioxide.
- Plants die and decay. During the decay process, bacteria eat the dead plants, break down the sugar for energy, and release carbon dioxide .
- Plants are destroyed by fire. When plants are burned, the sugar combines with oxygen to release carbon dioxide. .
All four of these processes occur according to the chemical reaction below:
`~CH_2O + ~O_2 -gt ~CO_2 + ~H_2O +` energy
Once carbon dioxide is released back into the atmosphere, the carbon cycle begins again.