Click the buttons to learn about the important role the ocean plays in Earth's Climate
The movement of carbon between the land, atmosphere, and ocean is called the carbon cycle. On land, plants absorb carbon dioxide and sunlight to make food, and are then consumed by animals—or they die and decay, releasing carbon back into the atmosphere. In the ocean, marine plants are part of a complex food chain in which carbon dioxide is transported to the deep ocean, locking it away for centuries or millennia. This biological carbon pump, in addition to carbon-trapping physical and chemical processes, makes the ocean a powerful “carbon sink.”
The biological carbon pump moves carbon from the surface ocean to deeper waters through the food web. Tiny plant-like organisms called phytoplankton use photosynthesis to turn sunlight and carbon dioxide into energy. They’re consumed by zooplankton, which are, in turn, eaten by animals that migrate from the twilight zone at night. The migrators’ poop sinks through the water as marine snow, effectively moving carbon to deep water, where it remains for centuries or more. Gelatinous salps are “super poopers'' that turn marine snow into dense particles that sink more rapidly.
Turbulent seas, driving wind, pouring rain—these are all physical processes that mix carbon dioxide from the atmosphere into the ocean. Carbon dioxide gas is soluble—meaning it can dissolve in seawater—but how much can be dissolved depends on the temperature and salinity of the water. Colder, less salty water absorbs more carbon dioxide while warmer, saltier water absorbs less. Other physical processes—upwelling and downwelling currents—then mix these carbon-rich waters vertically, distributing them throughout the ocean.
WHOI scientists have developed new technologies to help them learn how twilight zone life stores carbon in the deep sea. One such tool is called a MINION. Press PLAY to learn how it works.