in which form is carbon stored in the ocean?

carbonate minerals in shells and coral reefs
carbon dioxide gas dissolved in sea water
organic matter in the form of dead organisms dissolved carbonic acid

All of the above forms of carbon can be found in the ocean. Carbonate minerals in shells and coral reefs are a primary form of carbon storage in the ocean. Carbon dioxide gas can also dissolve in seawater, forming carbonic acid. Lastly, organic matter in the form of dead organisms can also contribute to carbon storage in the ocean.