Great Barrier Reef is expected to undergo a new “bleaching event”, say scientists

ABC News, Australia, reports 19th December 2015: Marine biologists studying the Great Barrier Reef are preparing for widespread coral bleaching early next year with an El Nino weather event predicted to turn many of the animals white.

Earlier this year, scientists predicted that the world’s third mass coral bleaching will happen in early 2016 and damage about 38 per cent of the world’s coral reefs.

Bleaching is a phenomenon that turns coral white or fades their colour and is caused by consistently warmer than average ocean temperatures.

The first mass coral bleaching event occurred in 1998, when about 16 per cent of the world’s reefs were affected. Up to 10 per cent of the corals on Queensland’s Great Barrier Reef died.

Australian Institute of Marine Science (AIMS) senior research scientist Dr Line Bay said they were “very concerned about the forecasts for this summer. The El Nino is as strong as it was in 1998 so the likelihood of marine heatwaves is high,” she said.

Dr Bay is currently breeding baby corals in her lab near Townsville to test their resilience to warm conditions. “Lots of people are surprised to hear that corals are animals but what we’re learning is that in fact they’re individuals too and some coral individuals are more tolerant than others,” she said.

“What we’re looking at is whether tolerant individuals will have tolerant babies and if so, if we can identify genetic markers.”

That resilience could prove important with bleaching events expected to occur more frequently in the future, reducing the reef’s recovery time.

‘We have to focus on the longer term strategies’

There have been three bleaching events on the Great Barrier Reef in the past two decades.
Dr David Wachenfeld, director of the Great Barrier Reef Marine Park Authority, said in every case, specific conditions combined to create the perfect storm.

“[The conditions are] very clear skies with lots of sunshine hitting the reef and very still water,” he said. “That does two things, it heats the water faster and it also causes stress to the corals from UV radiation.”

While researchers will closely monitor bleaching early next year to better understand the phenomenon, they cannot do anything to stop it.

“What that means is we have to focus on the longer term strategies,” Dr Wachenfeld said.

“What the reef needs for a healthy future is strong, concerted action on climate change. Simultaneously to have strong local action to fix up water quality, coastal development and unsustainable fishing practices.”

Source: ABC News (Australian Broadcasting Corporation), 19th December 2015. For the full text, see
www.abc.net.au/news/2015-12-19/scientists-brace-coral-bleaching-great-barrier-reef-2016/7042658

Note: In an interview in The Guardian, 21st December 2015, David Attenborough observes: The reef is only roughly 10,000 years old, so if it was slowly changed, the natural world would change but it wouldn’t be catastrophic because it would evolve. But if it changed in 50 years, from an increase of 2°C in the sea temperature, which would kill the coral, that would be catastrophic. And we are heading for that — the next decade or two you could see real disaster.

Source: The Guardian : www.theguardian.com/travel/2015/dec/21/david-attenborough-great-barrier-reef-australia


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