All living things contain carbon What happens to the carbon in their bodies when they die?

Answer 1

Most of it ends up as carbon dioxide in the atmosphere. Most dead bodies are decomposed by various types of microbe, which means they are used for respiration to release energy: carbon compounds + oxygen = carbon dioxide plus water.

This is an oversimplification of the complex changes that go on. The carbon dioxide is then absorbed by vegetation and sea algae and turned back into large, carbon based molecules, releasing oxygen. The (very rare) exception is when a large amount of dead forest was buried (such as after the Carboniferous period) and oxygen was excluded, so instead of bacteria eating it, it fossilised into coal. Carbon is also stored in the form of oil when most microscopic sea life died and sank to the bottom, and was buried. Much of this stored carbon has been burned in the last 2 centuries (a very short time) and this, together with deforestation, has shifted the equilibrium of the carbon cycle.

Answer 2

When a living thing dies, the carbon in its body can undergo decomposition by microorganisms, releasing carbon dioxide back into the atmosphere. In some cases, the carbon can also be preserved in the form of fossils or organic matter in soil.