Cyclone Yasi likely to have ravaged Great Barrier Reef

Scientists fear the storm has pulverised coral into rubble and left a swath of destruction
James Woodford guardian.co.uk 4 Feb 11;

On its way to ravaging cities and towns in north Queensland, severe tropical cyclone Yasi will almost certainly have left a swath of destruction on the Great Barrier Reef off Townsville.

Early last month, as floods struck southern Queensland, I accompanied a team of divers from the Australian Institute of Marine Science on an expedition to a 300-mile part of the reef – a fifth of the 1,400-mile-long World Heritage Area.

The researchers dived 13 reefs – from Myrmidon, which is 75 miles out to sea, to areas around the inshore Palm Island group, just off the mainland. Much of what we saw was spectacular and showed the reef recovering from a decade of devastation caused by coral bleaching and crown-of-thorns starfish, both of which have been responsible for large areas of coral mortality.

It may be weeks or months before scientists can fully survey and assess the damage from cyclone Yasi but, based on the effect of previous large cyclones, they will not be optimistic. Tropical cyclones generate huge waves, which pulverise coral reefs into rubble.

In March 2009, category four tropical cyclone Hamish travelled in an unusual path from north to south, tracking parallel to the coast and not making landfall. It is estimated to have affected a quarter of the Great Barrier Reef.

A year later I was able to dive in one of the areas hit by cyclone Hamish, also with scientists from the Australian Institute of Marine Science. Much of what we saw at the Swains, at the southern end of the Great Barrier Reef, was denuded of life. Numerous coral bommies, many the size of big cars, had been lifted up on to the reef flat by the force of the storm. It can take years, or even decades, for such a coral ecosystem to recover fully.

Scientists fear that as climate change tightens its grip devastating storms such as cyclones Yasi and Hamish will become more frequent and intense. However, it is not just the direct impacts of these storms that can damage the reef.

In the wake of the Queensland flooding, a coral ecologist at the Australian Institute of Marine Science, Dr Katharina Fabricius, warned that floodwaters carrying high nutrient loads from agricultural and urban catchments could lead to outbreaks of crown-of-thorns starfish. The starfish feed on coral, quickly denuding entire reefs.

Last year Fabricius and her colleagues published new evidence that nutrients in floodwaters provide food to the starfish larvae, increasing their survivability.

These are nervous days for the marine biologists who study the Great Barrier Reef and the authorities responsible for its good health.

James Woodford is the author of The Great Barrier Reef (Pan Macmillan)

Yasi does 10yrs damage to Barrier Reef
ABC News 5 Feb 11;

Authorities say hundreds of kilometres of the Great Barrier Reef hit by Cyclone Yasi will take up to 10 years to recover.

It is still too early for the Great Barrier Reef Marine Park Authority to send divers out to do a full assessment, but coral from the reef has been washing up on nearby shores.

The damage is expected to be similar to that of Cyclone Larry five years ago.

The authority's chief executive, Russell Reichelt, says all the progress the reef has made since then will now be destroyed.

"We can expect to see smashed coral beds, movements of coral boulders, sand and rubble moved around," he said.

"If there's any sand islands there and importantly sea grass beds, when they get disturbed - which they do by cyclones - then animals like dugong get affected."

Mr Reichelt says cyclones are not as damaging to reefs as the effects of climate change.

But he says Yasi will have still caused major destruction.

"Coral will begin regenerating immediately and be visibly restored in five to 10 years, but it changes the shape of the reef for very long periods - islands can be formed, boulders can be thrown up," he said.

Cyclone adds to Barrier Reef's flood woes
Matt Siegel (AFP) Google News 6 Feb 11;

SYDNEY — Hammered by a monster cyclone just weeks after flooding spewed toxic waste into its pristine waters, Australia's Great Barrier Reef could face a slow recovery due to climate change, experts warn.

Severe Tropical Cyclone Yasi, a top-category storm, ripped through Australia's northeast tourist coast Thursday, 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 (180 mile) per hour winds.

"Cyclones do damage reefs," Nick Graham, a senior research fellow at James Cook University, told AFP.

"They tend to be 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 (133,000 square miles) 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.

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.

"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 Professor 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."

Coral growth has slowed markedly on the reef since 1990 and parts of it have suffered severe bleaching due to rising sea temperatures and acidity that kill its plant-like organisms, leaving just the white limestone skeleton.

Overall, both this and cyclone damage are symptoms of worsening and dangerous climate change, said John Merson, from the University of New South Wales.

"I think probably more damage is being done (to the reef) by the rising temperature in the ocean which is causing the cyclone, as well as the reef to be damaged," said Merson.

"The other question is the complete lack of attention being given to the fact that we have a category five cyclone because we have climate change, yet we completely ignore this factor in the whole thing.

"The same thing -- the heating of the water -- is going to increase coral bleaching which will knock out the reef in the long term anyway."