When the rocks reach the bottom they are placed under heat and pressure which then will lead to a volcanic eruption releasing carbon back into the atmosphere
First the ocean will absorb carbon from the atmosphere diffusing - mixing atmosphere subjects with the surface of the ocean - and dissolving.
Notes: Diffusion does depend on variables including wind, ocean temperature, sea surface mixtures, and carbon concentrations
How is the ocean a carbon reservoir?
This chalky substance will then fall to the seafloor and it will attach it self to animals with shells. When those animals die they fall to the ocean floor creating rocks lying on the seafloor
Once the carbon is fully absorbed, the ions, that were once released from rocks, will combine with bicarbonate creating an antacid leads to a chalky white substance.