The ebb and flow of carbon within Earth's systems are complex and ever-moving occurrences. Carbon is a nomadic element, traveling between the atmosphere, ocean, and the soil, rock, and ice of the planet, changing forms along the way. Much of this cycling takes place in the ocean, partially through a biological carbon pump (BCP). In the BCP, atmospheric carbon is fixed through phytoplankton growing at the surface of the sea. When the phytoplankton dies, carbon particles sink from the surface to deep ocean waters. This carbon can remain for hundreds or even thousands of years before returning to the atmosphere.