Many factors determine the fate of carbon in the ocean.
Oceanographers have known for quite some time that the circulation and biology of the ocean play major roles in distributing carbon. Sinking of these surface waters to the deep drives an overturning ocean circulation that transfers heat, CO 2 and oxygen into the deep ocean. After several thousand years, deep water which has high levels of CO 2 returns to the surface in regions of upwelling such as the Equatorial Pacific. Photosynthesis in the ocean also acts to transfer carbon dioxide to the deep ocean. The fecal pellets of the animals that consume these plants and, ultimately, the phytoplankton's carcasses, or detritus, sink down to the deep ocean, where it stays for thousands of years.