Coral reefs are among the most diverse ecosystems in the world. This biodiversity makes them a high priority for conservation. The brilliant corals of Sogod Bay, above, live in one of more than 400 marine protected areas (MPAs) in the Philippines.
MPAs help to conserve biodiversity by preventing practices like coral harvesting and dynamite fishing. Unfortunately, there are also global dangers facing coral reef habitats that cannot be withheld by MPA boundaries.
The impact of ocean acidification on corals is one of these dangers. Oceans absorb carbon dioxide (CO2) from the atmosphere. Carbon dioxide reacts with seawater to form carbonic acid. Due to increases in carbon emissions, more CO2 is entering the world’s oceans, which creates additional carbonic acid in the water.
The more acidic seawater becomes, the less calcium carbonate it can hold. Many marine species, including coral, need calcium carbonate to build their protective shells and exoskeletons. Without it, shells grow slowly and become weak. Coral reefs with breakable, slow-growing corals erode more quickly than they accrete. Reefs can disappear, and the extinction of entire species is possible.
Efforts are being made in the Philippines to increase awareness of the potential impacts of ocean acidification. However, it will take global action to decrease our carbon emissions and help to protect the world’s fragile coral reef ecosystems.
National Geographic Education. Web site.
