Carbon cycle diagram

Credit: UCAR

This fairly basic carbon cycle diagram shows how carbon atoms 'flow' between various 'reservoirs' in the Earth system. This depiction of the carbon cycle focusses on the terrestrial (land-based) part of the cycle; there are also exchanges with the ocean which are only hinted at here. Note that carbon atoms are incorporated into various molecules as they flow around the cycle; for example, photosynthesis in plants captures carbon atoms in sugar molecules and atmospheric carbon is contained in molecules such as carbon dioxide and methane.