Cyclone Yasi's blistering 290 kilometre per hour winds are likely to have harmed the Great Barrier Reef, but it's too soon to tell the full extent of the damage, said experts.
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SYDNEY: Hammered by a category five cyclone just weeks after floodwaters spewed toxic waste into its pristine waters, Australia's Great Barrier Reef could face a slow recovery due to climate change, according to experts.
Severe Tropical Cyclone Yasi, a top-category storm, ripped through Australia's north-east tourist coast, levelling houses and decimating crops as it hit land near the city of Cairns, gateway to the Reef.
Though it is too early to assess the extent of the damage, marine experts said the sprawling coral structure was bound to have been harmed by Yasi's blistering 290 kilometre per hour winds. "Cyclones do damage reefs," said Nick Graham, a senior research fellow at James Cook.
Shallow waters most vulnerable
"They tend to be particularly damaging in shallow waters, so they can break corals and kill areas of live coral, so you get a reduction of coral cover.... And that then can have a knock-on effect," Graham said.
The world's largest living organism, which stretches for 345,000 square kilometres off Australia's northeast coast, was already suffering after last month's record flooding washed a mucky cocktail of debris, sediment, pesticides and other run-off out to sea.
Storms such as Yasi have the power to reduce reefs to rubble and wreak severe damage on living corals.
Cyclones a part of a reef’s life
Smashed fragments have already begun washing up on Australian beaches, according to the Great Barrier Reef Marine Park Authority, who estimate that recovery could take 10 years. "Cyclones are regular events and do affect the coral reef ecosystem dramatically," said the authority's chairman Russell Reichelt.
"However, they tend to be localised to a specific area, compared to other large-scale effects such as mass coral bleaching caused by climate change."
Cyclones are a fact of life on the reef - there were 55 between 1969 and 1997 according to a recent study - but warming and acidification of the ocean linked to climate change have both increased their frequency and left corals more vulnerable.
Reefs not so resilient
"What normally would have recovered in the past in many other places in the world takes a long time because the reefs are not optimal; they don't have a lot of resilience," said Ove Hoegh-Guldenburg, director of Queensland University's Global Change Institute.
"The second thing that is happening is that as we heat the oceans through global warming, we are increasing the frequency of mega cyclones like Yasi.... which potentially, given (the) circumstances, can have really big impacts on coral reefs, reducing their ability to bounce back."
