Acid killing off coral reefs: 18-10-2007
Tourists who have not yet had the pleasure of seeing the world's coral reefs may not have a chance in the future, as scientists warned that greenhouse gases are causing a build-up of acids in the ocean, which could destroy the marine organisms.
Australia's Great Barrier Reef could be affected by the problem, which occurs when there is too much carbon dioxide in the air and it dissolves in the waters, becoming carbolic acid. The presence of the acid makes it difficult for corals and other marine life made up of chalk to calcify.
Corals and plankton are at the bottom of the marine food chain, which if they decrease in numbers, could in turn affect the creatures which rely on feeding on them for survival.
Presenting their findings at a scientific forum in Canberra Thursday, Prof. Malcolm McCulloch of the Australian National University, said: "It appears this acidification is now taking place over decades, rather than centuries as originally predicted."
"It is happening even faster in the cooler waters of the Southern Ocean than in the tropics," he said. "It is starting to look like a very serious issue."
"Analysis of coral cores shows a steady drop in calcification over the last 20 years," added Professor Ove Hoegh-Guldberg of the University of Queensland. "When CO2 levels in the atmosphere reach about 500 parts per million, you put calcification out of business in the oceans."
He said: "It isn't just the coral reefs which are affected - a large part of the plankton in the Southern Ocean, the coccolithophorids, are also affected. These drive ocean productivity and are the base of the food web which supports krill, whales, tuna and our fisheries."
In conclusion, he said: "The risk is that this may begin to erode the Barrier of the Great Barrier Reef at a grand scale.
"As an issue it's a bit of a sleeper. Global warming is incredibly serious, but ocean acidification could be even more so."
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