The oceans make up two thirds of the Earth’s surface, and nearly all animal sea-life ultimately depends on green plants. So what are these plants? In sun-drenched shallow seas seaweeds are an important source of food for many marine animals.
But the basis for most animal life in the ocean is invisible to the naked eye. In the sunny surface waters of the oceans, tiny photosynthesisers drift around with the currents. They are so small that one litre of water can contain more than five hundred million of these minute organisms. These phytoplankton are short-lived, but they reproduce rapidly when conditions are good. Some make shelly hard parts of calcium carbonate.
Phytoplankton are a food for many other organisms - including the whale. - although the major whale food, krill, is an animal (zooplankton).
Where do you find the carbon?
Phytoplankton, seaweed and algae in the ocean
What form of carbon?
Organic carbon and calcium carbonate
How long will the carbon remain?
Only weeks, on average
How much carbon is there?
About 2 x 1012 kg C