AUSTRALIA: Global warming may be the leading cause of widespread coral bleaching threatening Great Barrier Reef, scientist says

The Great Barrier Reef in Australia is the world's largest natural feature, attracting nearly 2 million tourists each year. But over the last 20 years, the reef has experienced the worst ever coral bleaching observed, prompting scientists to warn of more severe bleaching to the reef due to global warming in the future. Professor Ove Hoegh-Guldberg leads a research team in Brisbane, Australia, which has been studying the effect of coral bleaching to the world's reefs, in particular to the Great Barrier Reef. His team has observed alarming intense and frequent coral bleachings to the reef in the past two decades which he says can be attributed to increased water temperatures. "Now when they become stressed, the little brown plant essentially gets kicked out of the coral and the result is that corals go from brown to white. Coral bleaching can occur for a number of different reasons. But more recently, it's been occurring because the seas in the tropical parts of the world are becoming too warm and because of that stress they've completely kicked out their plants out over hundreds of square kilometres of coral reef, turning white. Now without the symbiosis, the coral is very vulnerable to disease and death," Professor Hoegh-Guldberg told Reuters on Thursday (February 1). Professor Hoegh-Guldberg said half of the corals in the Western Indian Ocean died, triggering major concern for the coral living in the Great Barrier Reef. "Places like the Western Indian Ocean were affected far more severely in 1998 than the Great Barrier Reef and in that case, in the Western Indian Ocean, fifty per cent of the corals that were living in those regions died in the space of a few months. And of course it's that type of scenario, as we warm the world's oceans under a global warming world, that has a lot of us concerned about the Great Barrier Reef," he said. Another alarming concern for the corals is increased carbon dioxide levels in the atmosphere, which increase water acidity and affect carbon ions. These ions are important building blocks for coral structures, and Hoegh-Guldberg says only a tiny increase in carbon dioxide levels could stop coral production altogether, which can severely effect fisheries and tourism. "Climate change is clearly a threat to the corals and the tiny plants that live in the tissues. But the issues go far beyond corals. Corals build a structure in which thousands of species live. And of course those thousands of species include species that are important for fisheries, and for tourism. So without corals, you have a severely degraded habitat and as far as other species, start to affect things like tourism. And for Australia, which is earning 5.8 billion dollars a year from tourism, that's a huge issue", he said. The Great Barrier Reef is the world's largest natural feature on earth, stretching more than 2,300 kilometres (1430 miles) along the northeast coast of Australia from the northern tip of Queensland to just north of Bundaberg. The reef includes over one third of the world's soft coral species, more than 1,500 species of fish and is home to six of the world's seven species of marine turtle. The reef attracts 1.9 million tourists each year and is a major contributor to the local and Australian economy, according to the Great Barrier Reef Marine Park Authority.

ITN Source | February 2, 2007

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