We began by discussing What Contains Carbon?
Turns out, a whole lot of things do! (See here for an explanation of some of the items listed in the Bellringer.)
All living things contain carbon.
In fact, living things are often referred to as "carbon-based lifeforms." There's even a whole branch of chemistry dedicated to studying only those molecules containing carbon! It's called "organic" chemistry, as in the word "organism." (The fruits and vegetables at the supermarket labeled "organic" mean they're all natural. They contain no artificial chemicals or preservatives).
Most carbon is stored in the oceans.
Storage areas, or reservoirs, are called carbon sinks. The majority of carbon is stored in the ocean, with only a small amount in the atmosphere. (<1%) Carbon dioxide gas diffuses into the water, meaning it dissolves in the same way that salt or sugar would. The gas can re-enter the atmosphere through the decomposition of dead and decaying organic matter (living things) or through the combustion, meaning burning, of fossil fuels.
The big concern of scientists right now is that human beings are burning a lot more fossil fuels than ever before because of all our factories, power plants, and automobiles (powered by internal combustion engines). Those fossil fuels come from decayed organic matter, and still contain much of the organism's carbon inside of them. When we burn coal or oil, we release the carbon back into the atmosphere where it adds to global warming through the greenhouse effect.
We'll talk much more about that tomorrow. Tonight, check out some of the Carbon Cycle links on the Resources page.