Australia: Marine scientists planning for 'one of the worst' coral bleaching events

Erin Parke ABC News 26 Nov 15;

Scientists across Australia are preparing for what could be the most damaging coral bleaching event in history.

It is feared rising sea temperatures, and this year's strong El Nino, could combine to damage delicate reef systems on both sides of the continent.

WA Department of Parks and Wildlife marine scientist Shaun Wilson said the signs were not good.

"At the moment what's building up, it looks like one of the strongest El Nino events on record, and previously when we've had those sorts of events, we've had extensive bleaching, so that's our concern," he said.

"It could be really bad, it could be one of the worst events we've seen, but it's hard to know yet."

Bleaching occurs when stress, such as heat, causes algae to be ejected from the coral in which it lives.

The loss of the food-finding algae strips the coral of its colour, and starves it of nutrients.

The result is albino reefs, and a loss of habitat for fish, with a trickle-down effect on tourism and fishing industries.

Water temperatures being monitored

Preparations are being made across Australia to monitor the water temperature and assess the damage as quickly as possible.

Marine scientists from several different institutions and agencies held a planning workshop in Perth this week.

Australian Institute of Marine Science research scientist James Gilmour said plans were being made to inspect some northern offshore reefs in January.

"We think the most important thing to do now is document how widespread and severe the bleaching is, and also understanding the physical conditions which have caused that bleaching events," Dr Gilmour said

"So we'll be mobilising teams together before the event in January, to try to do some surveys and deploy some oceanographic equipment.

"Then after the event, should it happen - probably in April - we'll be going back to the sites, to look at how much coral has or hasn't died, and also pulling the oceanographic instruments to understand the conditions that caused the mortality."

Coral can recover from bleaching, but it takes years for the algae to restore.

Dr Gilmour said there was concern that over the next decade, warming waters would increase the number of bleaching events and push the reefs to breaking point.

"What we've learned from work we've already done in places in north-western Australia is following a severe bleaching event, some reefs can recover, but it takes a takes a good 10 years to recover," he said.

"So the concern is that if we start to see multiple bleaching events happening within ten years, then the reefs just won't have the capacity to recover."