Global CO2 and Temperature Balances

The oceans also serve as a buffer for carbon dioxide. On average, the oceans hold 60 times more CO2 than the atmosphere. When dissolved in water, CO2 forms carbonic acid (H2CO3), bicarbonate (HCO3 ) and carbonate (COs ). Sea water is slightly alkaline, with a surface pH of 8.2, so it readily reacts with H2CO3. However, rapid exchange with the atmosphere only occurs in the upper wind-mixed layer, which is about 300 feet (100 meters) thick. This layer contains roughly one atmosphere equivalent of CO2. 

CO2 in its various forms is removed from the sea by foraminifera, coral reefs, and other marine organisms, which produce solid calcium carbonate. 

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