Carbon is a primary element that plays a central role in regulating the Earth's climate.
A buildup of carbon in the atmosphere in the form of carbon dioxide can contribute to global warming because it acts as a blanket that traps heat against the Earth. Of the some 100 billion tons of carbon dioxide removed from the atmosphere each year through the process of photosynthesis, roughly half is thought to be taken up by the large numbers of phytoplankton in the surface layer of the world's oceans. These microscopic plants, the organisms that feed on them, and their debris comprise the oceanic reservoir of particulate organic carbon. Some of this carbon eventually sinks to the deep ocean, where it is sequestered for long periods of time and cannot interact with the overlying atmosphere. To date, scientists have had little data about how much of this particulate organic carbon is actually present throughout the world's oceans because they have been forced to rely on sporadic sampling from ships.