Animals of the coral reef need calcium carbonate to build their skeletons. In this activity, students compare the formation of coral reefs today when there is still an abundance of carbonate present in the ocean to bond with the calcium to coral reefs built in a possible future ocean where there is not enough carbonate available. Calcium carbonate is the combination of two ions dissolved in sea water, Calcium which is Ca+2 and carbonate which is CO3 -2 to form CaCO3.
“With ocean acidification, corals cannot absorb the calcium carbonate they need to maintain their skeletons and the stony skeletons that support corals and reefs will dissolve. Already, ocean acidification has lowered the pH of the ocean by about 0.11 units (SCOR 2009). Moving the ocean's pH from 8.179 to a current pH of 8.069, which means the ocean is about 30% more acidic now than it was in 1751 (SCOR 2009). If nothing is done to reduce carbon dioxide emissions into the atmosphere, ocean acidification will increase and more and more corals will be damaged or destroyed.” See How Does Climate Change Affect Coral Reefs?