Is the ocean a carbon sink or a carbon source

Explanation:

The Carbon CycleChanges to The Carbon CycleThe Ocean and CarbonBiological Pump

The ocean plays an important part in the carbon cycle. Overall, the ocean is called a carbon ‘sink’ because it takes up more carbon from the atmosphere than it gives up.Carbon dioxide from the atmosphere dissolves in the surface waters of the ocean. Some of the carbon dioxide stays as dissolved gas, but much of it gets turned into other things. Photosynthesis by tiny marine plants (phytoplankton) in the sunlit surface waters turns the carbon into organic matter

the ocean is a carbon sink

i believe it would be c: tons.