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02/28/2006:

"Acid Seas Kill Off Coral Reefs"

THE world’s coral reefs could disappear within a few decades along with hundreds of species of plankton and shellfish, according to new studies into man’s impact on the oceans.

Researchers have found that carbon dioxide, the gas already blamed for causing global warming, is also raising the acid levels in the sea. The shells of coral and other marine life dissolve in acid. The process is happening so fast that many such species, including coral, crabs, oysters and mussels, may become unable to build and repair their shells and will die out, say the researchers.

“Increased carbon dioxide emissions are making the world’s oceans more acidic and could cause a mass extinction of marine life similar to the one that occurred on land when the dinosaurs disappeared,” said Professor Ken Caldeira of the Carnegie Institution’s global ecology department.

When CO2 produced by burning fossil fuels dissolves in the ocean, it forms carbonic acid. A little of this can benefit marine life by providing carbonate ions — a vital constituent in the biochemical process by which sea creatures such as corals and molluscs build their shells.

Caldeira found, however, that the huge volumes of carbon dioxide being released by humans are dissolving into the oceans so fast that sea creatures can no longer absorb it. Consequently, the levels of carbonic acid are rising and the oceans are “turning sour."
commondreams.org