Acid in the Seas

"Worldwide emissions of carbon dioxide from fossil fuel burning are dramatically altering ocean chemistry and threatening marine organisms, including corals, that secrete skeletal structures and support oceanic biodiversity. A landmark report released today summarizes the known effects of increased atmospheric carbon dioxide on these organisms, known as marine calcifiers, and recommends future research for determining the extent of the impacts."

"The report, "Impacts of Ocean Acidification on Coral Reefs and Other Marine Calcifiers," warns that oceans worldwide absorbed approximately 118 billion metric tons of carbon between 1800 and 1994. Oceans are naturally alkaline, and they are expected to remain so, but the interaction with carbon dioxide is making them less alkaline and more acidic. The increased acidity lowers the concentration of carbonate ion, a building block of the calcium carbonate that many marine organisms use to grow their skeletons and create coral reef structures."

Slowing skeletal growth
"Experimental studies, such as those conducted by one of the report's authors, Chris Langdon at the University of Miami, show that coral calcification consistently decreases as the oceans become more acidic. This means that these organisms will grow more slowly, or their skeletons will become less dense, a process similar to osteoporosis in humans. As a result, reef structures are threatened because corals may be unable to build reefs as fast as erosion wears away the reefs."

Threats to major ecosystems

"Several other major ecosystems that are supported by marine calcifiers may be particularly threatened by ocean acidification. These include cold-water reefs, which are extensive structures that provide habitat for many important fish species, particularly in the coastal waters of Alaska."