Photo by NOAA/David Burdick
Ocean acidification is a process in which Carbon Dioxide reacts with water in the air and during precipitation falls as carbonic acid. This reduces the pH of the sea and also means carbonate becomes less readily available making it more difficult for the corals to lay down their calcium carbonate skeletal structure. In every coral reef the corals build their structure as fast as they can to try and compete with bio-erosion through parts being knocked off or eaten along with gentle erosion from the sea. This is especially prominent in a sea that has a high level of carbon dioxide as not only can the corals not grow as fast but they are weaker. This amounts to them being weaker and not as able to cope with the causes of bleaching leading to destruction and ultimately because of this the coral reefs will shrink. Although acidification does not directly bleach the corals it leaves them more susceptible to bleaching through other causes.