Great little article on ABC Science website. Bernie says, ” ‘Cycle’ is a generous description for the movement of carbon around the planet. Festival of double-headed arrows and maths is more like it.”
Bernie goes on, “Like most elements, carbon atoms are constantly being recycled from one molecular form to another, thanks to chemical reactions. We’re still dealing with the same roll call of atoms we had when the planet was formed (radioactive decay aside) — they just constantly get reorganised. So a quick background check of the carbon inside you might reveal atoms that have done a tour of duty in the sea floor, a dinosaur or any number of trees, pets and petrol tanks.
It’s carbon’s unique chemistry that gives it a finger in every biological, geological and geographical pie that’s going. There are gigatonnes (literally billions of tonnes) of the stuff dissolved in oceans, waiting to be incorporated into sea-shells. From there it’s a slow, high-pressure trip to the mother lode of carbon stashes: carbonate rocks like limestone.”