For years it was thought that carbon dioxide absorption into the oceans would benefit the environment as it reduced the amount of greenhouse gasses present in the atmosphere. It became clear after careful observation of the oceans over time that excess carbon dioxide created a chemical reaction in the water that resulted in the release of free hydrogen in larger-than-average quantities. This led to a dramatic increase in oceanic acidity levels and became highly damaging to marine life, the chemistry of which is explained below.
It is estimated that 30 to 40% of all anthropogenic carbon emitted into the atmosphere is absorbed by oceans. When CO2 reacts with water molecules, it produces carbonic acid (H2CO3). Hydrogen ions (H+) detach from carbonic acid, leaving bicarbonate molecules (HCO3-) free to float. High amounts of CO2 dissolving in the oceans results in a higher concentration of the free hydrogen ions, reducing the pH of the water and creating a more acidic solution. The chemical equation of carbon dioxide and water is as follows:
CO2 + H2O H2CO3 HCO3- + H+
Shelled marine life like oysters, crabs, and shrimp rely on carbonate (CO3-2) present in the water, to bind with calcium ions (CA+2) to form calcium carbonate (CaCO3). The equation is as follows:
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CO3-2 + 2H+ 2HCO3-
Thus when the oceans become more acidic, the free hydrogen ions block marine life from creating the protective shelter that they need; the shells become porous and more energy is required to complete anabolic processes. This marine life not only relies on calcium but also forms of calcium that are indicative of a more alkaline