We’ve all come to associate the increasing carbon dioxide in our atmosphere with warming and rising ocean waters. But the carbon dioxide we pump into the atmosphere has a less well-known consequence for the ocean: when mixed with sea water it forms carbonic acid and raises the acidity of the marine environment.
Calcium dissolves in acidic water, which makes life more difficult for the many intertidal creatures that extract calcium from the water to incorporate in their bodies. Altering the ocean’s acidity will have consequences for biodiversity and for the abundance, health, biochemistry, physiology, and even behavior of certain species. If carbon dioxide emissions continue to increase, we may see the results in the intertidal in just a few decades.
Mollusks such as the familiar California blue mussels, abalone, perwinkles, turban snails, and top snails may be unable to form shells, or their existing shells may become pitted and frail. Crustaceans such as barnacles and crabs will have difficulty extracting calcium to create their protective armor. Even a sea star’s body needs some calcium, and the consequences for sea urchins may be devastating.
During the 2010 United Nations Climate Change Conference in Cancun, Mexico, the United Nations Environment Programme (UNEP) issued a report on ocean acidification. The main thrust of the report is the probable impact to global food security. It makes an interesting and sobering read.