Describe How Carbon Dioxide Acts as a Buffer in Seawater

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The Answer is The proportion of carbon dioxide gas in the ocean is greater than that in the atmosphere; however CO₂ still readily dissolves into seawater because it reacts with H₂O to change chemical forms. In the ocean, CO₂ combines chemically with water to form carbonic acid, (H₂ CO₃), which can further break down into bicarbonate (HCO₃^-) and carbonate (CO₃^2-). While carbonic acid will lower pH (more acidic), formation of bicarbonate and carbonate increase pH (more alkaline). These chemical changes help to balance pH and hence act as a buffer. This chemical equilibrium is important for marine organisms because the carbonate ions are an important component of calcium carbonate (CaCO₃), the compound that forms the skeletal material of many marine organisms (sponges, corals, snails, sea stars, etc.). An increase in CO₂ ultimately reduces the amount of carbonate available to organisms for building their skeleton, another threat to their survival.

Describe How Carbon Dioxide Acts as a Buffer in Seawater

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