Bleached coral can be seen at the Keppel Islands on the southern Great Barrier Reef in Queensland in this May 2006 handout photograph. The reef, and possibly the $5.8 billion ($4.5 billion) tourist industry it underpins, will be "functionally extinct" by 2050, a draft report by the Intergovernmental Panel on Climate Change (IPCC) warned this week.  (Xinhua/Reuters Photo)

    BEIJING, May 9 (Xinhuanet) -- Warmar sea temperatures are blamed for the severity of a coral disease, according to a study on Australia's Great Barrier Reef published on Tuesday in the online journal PLoS Biology.

    The study tracked the relationship between water temperature and the frequency of a coral disease called white syndrome, an ailment that turns corals white, across more than 1,800 kilometer of the world's largest coral reef.

    In the study, scientists found white syndrome flourished when the sea temperature rose. In 2002, for example, the frequency of the disease increased 20-fold after a year in which the region saw its second warmest summer.

    In another case, two years ago, unusually hot water across the Caribbean Sea was blamed for a massive surge of coral bleaching, a different phenomenon from white syndrome, and a subsequent wave of deadly diseases that attacked reefs across the region.

    In some locations, scientists found a 25 to 30 percent loss of coral and centuries-old corals were killed.   

    The study found that the effect of temperature was "highly dependent" on the density of the coral cover. Outbreaks of white syndrome followed unusually warm temperature on reefs with greater than 50 percent coral cover.    

    Reefs are undersea rock formations built by tiny animals called coral polyps. They are important habitats and nurseries for fish and other sea creatures.

    Scientists estimate about a quarter of the world's coral has been permanently lost and another 30 percent could disappear over the next 30 years.

(Agencies)