Mass coral bleaching is occurring on the Great Barrier Reef for the second consecutive year, Australia’s lead management agency for the Reef confirmed yesterday (10 March).
Experts from the Great Barrier Reef Marine Park Authority spent six hours flying over the Reef between Townsville and Cairns, alongside researchers from the Australian Institute of Marine Science.
The aerial survey of the Reef, the first for 2017, found severe bleaching in offshore reefs from north of Ingham to the northern extent of the survey near Cairns.
This year more bleaching is being observed in this central part of the Reef, which last year escaped widespread severe bleaching.
Marine Park Authority Director of Reef Recovery Dr David Wachenfeld said the survey confirmed anecdotal reports from visitors and reef surveys of bleaching from marine park rangers and commercial operators.
‘Mass bleaching is occurring on the Great Barrier Reef for the second consecutive year.
‘How this event unfolds will depend very much on local weather conditions over the next few weeks.
‘Importantly, not all bleached coral will die. As we saw last year bleaching and mortality can be highly variable across the 344,000 square kilometre Marine Park — an area bigger than Italy.’
DR DAVID WACHENFELD
Great Barrier Reef Marine Park Authority Director of Reef Recovery
Dr Neal Cantin from the Australian Institute of Marine Science (AIMS) said the recurrence of widespread coral bleaching in back-to-back summers indicated there was not enough time between last year’s extreme heat event for the corals to fully recover.
‘We are seeing a decrease in the stress tolerance of these corals. This is the first time the Great Barrier Reef has not had a few years between bleaching events to recover.
‘Many coral species appear to be more susceptible to bleaching after more than 12 months of sustained above-average ocean temperatures.’
DR NEAL CANTIN
Australian Institute of Marine Science
Marine Park Authority experts and scientists from the ARC Centre of Excellence for Coral Reef Studies will take to the sky again next week to resurvey 1150 reefs along the entire Great Barrier Reef.
‘I’ve been photographing this area of the reef for several years now and what we’re seeing is unprecedented.
‘In these photos nearly 100% of the corals are bleaching, and who knows how many will recover. Algae is already beginning to overgrow many of the corals.
‘Just a few months ago, these corals were full of colour and life. Now, everywhere you look is white. The corals aren’t getting the chance to bounce back from last year’s bleaching event. If this is the new normal, we’re in trouble.’
BRETT MONROE GARNER
Conservation photographer and marine biologist
In 2015, UNESCO placed the Great Barrier Reef on its watchlist due to concerns about the Australian government’s management of the World Heritage Area.
Despite this, the Australian government is considering giving AU$1 billion (US$700 million) to the biggest coal mine ever built in the country. The Carmichael mine in the state of Queensland is set to be a climate bomb that endangers the reef and defies the Paris climate agreement.
‘Climate change is fuelling warmer waters, cooking the reef alive. Once a coral is dead, it’s gone forever.
‘We have on our doorstep the clearest signal that climate change is happening, and that governments aren’t moving fast enough to stop it. We can still stop the Reef’s destruction if we dramatically reduce global emissions.
‘While the reef is fighting for its life, the Australian government is funding its destruction. Tackling climate change is the only real solution here, and that starts by stopping public funding for climate-killing coal projects.’
ALIX FOSTER VANDER ELST
Campaigner for Greenpeace Australia Pacific
The appetite for coal in markets such as India and China is also stalling; India has said it won’t need to import Australian coal after 2020 – yet Australia’s government continues to subsidise the industry while one of its greatest natural wonders vanishes before its eyes.
When water is too warm, corals expel the algae (zooxanthellae) living in their tissues causing the coral to turn completely white. If water temperatures don’t return to normal within six to eight weeks of the bleaching, the coral dies. Reef ecosystems live near the surface of the water, where the rise in ocean temperature is strongest.
Corals can survive a bleaching event, but it puts them under severe stress. In 2016, 93% of the corals of the Great Barrier Reef bleached and 22% of the entire Reef died.
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