Severe coral bleaching worsens in most pristine parts of Great Barrier Reef

Expert blames global warming, as coral bleaches when water temperatures go above a certain threshold for an extended period of time
Michael Slezak The Guardian 14 Mar 16;

Damage to parts of the Great Barrier Reef has worsened, leading authorities to raise the alert to the second-highest level, indicating severe local coral bleaching.

The bleaching is worst in the most pristine and remote parts of the reef north of Cairns, according to Terry Hughes, convenor of the National Coral Taskforce. “It’s the jewel in the crown of the Great Barrier Reef and it’s now getting a quite a serious impact from this bleaching event,” he said. “The northern reefs are bleaching quite badly now.”

Hughes said it appeared there was some coral death occurring in northern reefs.

Russell Reichelt, the chairman of the Great Barrier Reef Marine Park Authority said the area around Lizard Island, 250km north of Cairns, and sites further north, had fared the worst.

The US National Oceanographic and Atmospheric Administration predicts bleaching conditions to worsen over the coming weeks.

The world is currently in the grips of the third global coral bleaching event. Coral bleaches when water temperatures are raised above a certain threshold for an extended period of time.

Hughes, director of the ARC centre of excellence for coral reef studies at James Cook University, said although the strong El Niño occurring now is partly to blame for the bleaching event, the real culprit is global warming caused by carbon emissions.

“These massive thousand-kilometer bleaching events didn’t happen thirty years ago,” he said. “No-one ever recorded a mass bleaching event in the 40s, 50s, 60s, 70s, until the middle of the 1980s … and the Great Barrier Reef didn’t bleach until 1998 for the first time.”

“The baseline temperature on the barrier reef has gone up between a half a degree and a full degree depending where you are on the great barrier reef. Bleaching happens once coral sits in water a degree or two above the normal summer maximum for a month or so.”

Moreover, Reichelt said climate change is expected to increase the severity El Niño weather patterns.

We're heading to a point where the Great Barrier Reef might bleach during every El ​​Niño, risking its very existence.

Hughes says we are heading towards a future where the Great Barrier Reef might bleach during every El Niño , which will put its existence at risk.

Based on the severity of bleaching reports, the Great Barrier Reef Marine Park Authority has lifted its bleaching warning from Response Level 1, which means mild and widespread bleaching, to Response Level 2 (severe and local).

The silver lining in the announcement is cloud cover and cooler temperatures have created safer conditions for two thirds of the reef – most areas south of Cairns.

“In the last couple of weeks we’ve had a lot of cloud cover in the middle and the south, so the danger period has basically passed for the reef south of Cairns.”

But the announcement has led to calls for immediate action from conservation groups around Australia.

Greenpeace called for Queensland to limit its coal exporting. “In the two weeks since the level 1 response plan began, the Queensland government has allowed some 8m tonnes of coal to be exported straight through this delicate ecosystem. This coal will be burnt overseas, driving climate change, warming our oceans and contributing to coral bleaching,” said Shani Tager, Greenpeace Reef Campaigner.

Society said: “As the bleaching on the Reef continues to intensify we need an urgent response from the Turnbull government to avoid widespread bleaching happening repeatedly in the future.”

“This bleaching event has revealed the true cost of approving more coal mines, more coal export port terminals and refusing to listen to the warnings ... The solutions are clear, we must make a rapid transition from mining and burning coal to 100% renewable energy.”

WWF-Australia called for an injection of $1m in federal funding for coral monitoring.

“GBRMPA is clearly concerned and is being proactive in lifting its response level and we support them in taking this action,” said WWF spokesperson Richard Leck.

“Surveying the impact of this bleaching event requires significant additional funds because of the challenges of getting scientists into the field over enormous distances.”


Coral bleaching threat level increased by Great Barrier Reef Marine Park Authority
Stephanie Smail ABC News 14 Mar 16;

Authorities monitoring the Great Barrier Reef Marine Park Authority have increased the coral bleaching threat level after divers found widespread loss of coral.

Great Barrier Reef Marine Park Authority (GBRMPA) chairman Dr Russell Reichelt said the area around Lizard Island, north of Cairns, and sites further north, had been hit hardest.

It warned there was a high risk of mass coral bleaching on the reef this month due to the hot, dry conditions associated with the El Nino weather system and high sea surface temperatures.

"This is the result of sea surface temperatures climbing as high as 33 degrees Celsius during February," Dr Reichelt said.

"In the far north, the surveys found severe bleaching on inshore reefs, along with moderate bleaching on mid-shelf reefs."

Bleaching dramatically increased in past two weeks

Since earlier today, divers from the GBRMPA have been working with the Queensland Parks and Wildlife Service and other scientists to survey the extent and severity of bleaching.

Dr Reichelt said GBRMPA would ramp up monitoring of the mass bleaching event in the coming days.

Lyle Vail, who runs the Australian Museum's Lizard Island Research Station north of Cairns, said bleaching had increased dramatically in the past two weeks, especially among shallow water corals.

"A couple of weeks ago you'd look around in the Lizard Island lagoon and see at least 50 per cent of corals were stressed to some level, but none had died," he said.

"Now you look around and see all the corals are highly stressed and a couple of colonies have died."

Earlier this month, Mr Vail said the bleaching was the worst to hit the island in more than 15 years.

Bleaching reported up to 30kms away from Lizard Island

He said it would take time for the coral to recover when cooler air and sea temperatures eventually arrived.

"Corals aren't going to miraculously recover. It takes them time, if they're going to survive, to get over such a stressful event," he said.

"It will take many weeks for the coral to get as close as it can to previous condition.

"The problem with having these high levels of stress is it will affect their growth and reproductive output in the future."

Mr Vail said other researchers monitoring corals in the area had reported bleaching up to 30 kilometres away from the island.

He said there were signs the worst weather was over.

"We're starting to see the sea temperatures go down gradually after a week of cloud cover and cooler air temperatures," he said.

Director of the ARC Centre of Excellence for Coral Reef Studies Professor Terry Hughes said the mass bleaching was a "real tragedy".

"After months of El Nino conditions, we had hoped that cloudy weather in the past few weeks would quench the overheating of the Great Barrier Reef along its entire length," said Professor Hughes.

He said extensive aerial surveys would begin this week, similar to those done during mass bleaching events in 1998 and 2002.

No comments:

Post a Comment