Losing Nemo: Scientists Mourn Great Barrier Losses
April 21, 2016
Scientists surveying the mass coral bleaching on the Great Barrier Reef say only 7 per cent of Australia’s environmental icon has been left untouched by the event.
The final results of plane and helicopter surveys by scientists involved in the National Coral Bleaching Taskforce has found that of the 911 reefs they observed, just 68 had escaped any sign of bleaching.
Overall, severe bleaching of between 60 and 100 per cent of coral was recorded on 316 reefs, almost all of them in the northern half of the barrier reef. Reefs in central and southern regions of the 2300 kilometre Great Barrier Reef have experienced more moderate to mild affects.
The mass bleaching event has been driven by significantly higher than average sea temperatures as a result of the current El Nino event, coupled with a long-term warming of the oceans due to climate change.
While the barrier reef has experienced mass coral bleaching events in the past – notably in 1998 and 2002 – Professor Terry Hughes, convenor of the bleaching taskforce, said the current event was by far the biggest.
Professor Andrew Baird, from the Centre of Excellence for Coral Reef Studies, said north of Port Douglas, “we’re already measuring close to 50 per cent mortality of bleached corals”.
“At some reefs, the final toll is likely to exceed 90 per cent.”
But in the southern regions corals have largely escaped damaging levels of bleaching due to cooler sea temperatures, Professor Hughes said, and it is expected most will survive and regain their normal colour in coming months.
The damage on the barrier reef is part of a global mass bleaching event that has hit corals hard in many places including Hawai, Fiji and New Caledonia. It is only the third global event in recorded history, with the other two occurring in 1998 and 2010.
Stretching for half a kilometre or so, Loomis Reef is the place where the alarm bells started going off.
Prof Justin Marshall has been diving this reef, about 270km north of Cairns, for 30 years. Right now he is, to say the least, angry.
“My veil is down,” he says, no longer bothering with the kind of polite niceties common among academics.
“I have cried. I have broken down in front of cameras. This is the most devastating, gut-wrenching fuck up,” says Marshall, of the University of Queensland.
Back in November, researchers and staff on the Australian Museum’s Lizard Island Research Station started to see the early signs of coral bleaching – faded colours, odd fluorescent hues and chunks of white.
The Great Barrier Reef, of which Loomis is just one of 3,000 reefs, is in the death throes of its worst ever coral bleaching event – part of the third global mass bleaching since 1998.
Latest figures show that 93% of the reef has been impacted by bleaching. The worst affected areas are in the reef’s north.
“Loomis Reef was an amazingly diverse, beautiful little reef about 500 metres long – covered in lots of different coral. Now it’s going to be a big ball of slime,” Marshall says. The past tense, it seems, is deliberate.
“It’s in an area that tourists use – you can pretty much snorkel there right from the shore. You don’t need a boat.
“At the closer end on Loomis there is a nice Porites coral – they can be thousands of years old. The one on Loomis would be maybe hundreds.”
“This is, by far, the worst bleaching they’ve seen on the Great Barrier Reef,” said Mark Eakin, head of the National Oceanic and Atmospheric Administration’s Coral Reef Watch, which partners with the Australian National Coral Bleaching Taskforce. “Our climate model-based Four Month Bleaching Outlook was predicting that severe bleaching was likely for the [Great Barrier Reef] back in December. Unfortunately, we were right and much of the reef has bleached, especially in the north.”