Every time one organism consumes another, organic carbon changes hands. The organic carbon from food is used to build tissue, or is broken down to give the animal energy. The carbon in the food is returned to the atmosphere as carbon dioxide.
Carnivores get their carbon from the bodies of other animals. Herbivores get theirs from plants. This means that all land consumers ultimately depend on photosynthesis.
Insects too are prodigious consumers. They turn over more carbon than all the larger land animals put together, although individually their lives are very short.
Where do you find the carbon?
What form of carbon?
How long will the carbon remain?
Less than one year on average
How much carbon is there?
About 1 x 1012 kg