The surface ocean is a thin, warm, well-lit layer of water. Carbon dioxide dissolves into the surface ocean from the air above.
In addition, a small amount of dissolved carbon comes from rivers. Much of the dissolved carbon will be hoovered up by the phytoplankton and recycled in and out of the bodies of other ocean creatures.
Herbivores, carnivores and decomposers depend on plankton, so life in the ocean is concentrated in this top one hundred metres or so of the sea.
All these organisms release carbon dioxide when they respire. Wind and currents ensure the water, the organisms and the dissolved carbon in the surface ocean are mixed together.
Where do you find the carbon?
The warm, well-mixed top 100-200 metres of the world's oceans
What form of carbon?
How long will the carbon remain?
About 8 years on average
How much carbon is there?
about 1000 x 1012 kg