reacts with CO3 - 2 in water to form bicarbonate ions). (realclimate.org)
These reactions are fully reversible and the basic thermodynamics of these reactions in seawater are well known, such that at a pH of approximately 8.1 approximately 90 % the carbon is in the form of bicarbonate ion, 9 % in the form of carbonate ion, and only about 1 % of the carbon is in the form of dissolved CO2. (metlink.org)
They looked for those that were triggered to release oxygen by bicarbonate ions, and found that human haemoglobin behaved like its counterpart in crocodiles if it contained a particular sequence of just 12 amino acids from the crocodile's haemoglobin. (newscientist.com)