The Ocean’s Silent Crisis: Acidification Explained

It is a natural process and part of the carbon cycle that carbon is exchanged between the sinks of the atmosphere and the ocean via diffusion (and occasionally processes such as photosynthesis and respiration by aquatic phytoplankton). In the atmosphere, carbon exists in the form of carbon dioxide. When the ocean and the atmosphere come in contact, and carbon dioxide in the atmosphere can dissolve (react with water) in the ocean to form carbonic acid.

However, when humans have added excessive amounts of CO2 into the atmosphere, more carbonic acid would end up in oceans. The ocean will be “taking up” the extra carbon in the atmosphere, as mentioned in the last paragraph. But this sudden increase of acid concentration in the ocean will cause ocean acidification. The large amount of carbonic acid in the ocean will react with carbonate ions to form bio carbonate, which leaves shell-building marine animals less carbonate ions for the building of their shells. The shells of these animals then evolve to become thinner and more fragile. Also, the ocean water, which is becoming acidic, can easily dissolve the carbonate shells of the shell-building animals. Both the acidifying of the water and the thinning of the carbonate shells cause shell-building animals to be more vulnerable in the ocean environment.