<P> The Earth's oceans contain a large amount of CO in the form of bicarbonate and carbonate ions--much more than the amount in the atmosphere . The bicarbonate is produced in reactions between rock, water, and carbon dioxide . One example is the dissolution of calcium carbonate: </P> <Dl> <Dd> CaCO 3 + CO + H 2O ⇌ Ca 2 + + 2 HCO − </Dd> </Dl> <Dd> CaCO 3 + CO + H 2O ⇌ Ca 2 + + 2 HCO − </Dd> <P> Reactions like this tend to buffer changes in atmospheric CO . Since the right side of the reaction produces an acidic compound, adding CO on the left side decreases the pH of sea water, a process which has been termed ocean acidification (pH of the ocean becomes more acidic although the pH value remains in the alkaline range). Reactions between CO and non-carbonate rocks also add bicarbonate to the seas . This can later undergo the reverse of the above reaction to form carbonate rocks, releasing half of the bicarbonate as CO . Over hundreds of millions of years, this has produced huge quantities of carbonate rocks . </P>

What is the approximate atmospheric life of co2