'We’re just on the knife’s edge': Scientists say Great Barrier Reef mass bleaching could be imminent

Scientists are warning the Great Barrier Reef could experience its third mass coral bleaching event in five years.

Great Barrier Reef

Source: Climate Council

With patches of stark-white bleached coral popping up around Magnetic Island - off the coast of Townsville - the Australian Institute of Marine Science warns that if conditions don’t improve soon, the Great Barrier Reef could experience its third mass coral bleaching event in five years.

AIMS Senior Principal Research Scientist, Dr Katharina Fabricius lives on Magnetic Island and said the situation on the island has deteriorated in the past four days, from moderate coral bleaching to the first coral mortalities.

“[We had] massive bleaching in 2016 and 2017 and now we’re just on the knife’s edge and it depends on the weather now whether or not we’re going to see another bleaching event,” Dr Fabricius said.
Bleached clam.
Bleached clam. Source: Dr Leon Zann
Widespread rain and cloud cover have brought a brief reprieve for the Great Barrier Reef, but multiple scientists have told SBS News they still hold concerns.

“It is still localised, it is still patchy bleaching but it is starting and if the weather clears up again the heat stress will continue and I’m really concerned that we could get another bleaching event,” Dr Fabricius said.

The Great Barrier Reef Marine Park Authority is also watching the reef closely.

GBRMPA confirmed it has observed moderate to severe bleaching in parts of Cleveland and Halifax Bays, including Magnetic Island.

“Due to the weekend widespread rain and cloud cover in this area, we don’t have current satellite information but these weather conditions did bring some much-needed cooling,” a spokesperson for GBRMPA said.

“The Reef is at a critical point in terms of thermal stress and local weather conditions over the next few weeks will play a key role in determining outcomes”.
Retired marine biologist Dr Leon Zann has lived on Magnetic Island on-and-off-again since 1971.

He said this is the worst coral bleaching he’s seen on the island in that time.

Dr Zann was so concerned about the rapid decline of the reef’s health, he started posting videos of the damage to YouTube.
His most recent video, posted on Tuesday, shows bleached giant clams in Nelly Bay.

“The NOAA (National Oceanic and Atmospheric Administration) scientists and marine scientists in Australia have been telling us for some months there’s a very large heatwave that will occur in the Great Barrier Reef, it seems to have arrived,” Dr Zann said.

“Water temperature, the ocean temperature off [Magnetic Island] was around 30C to 32C, pretty warm. And in the shallows here up to 33, 34, 35 even in the shallows”.

SBS News visited Magnetic Island in December 2019 to report on the health of the Great Barrier Reef.

At the time, James Cook University PhD candidate Blanche d’Anastasi said she was concerned about the health of the reef in the island’s waters.

Today, she says she’s devastated.

“It’s really confronting because these corals, the fact that they’re bleaching it means they’ve been hotter than they’ve been before so they’re getting really stressed,” Ms d’Anastasi said.

“With the hot, still conditions and the marine heatwave the water has heated up to an uncomfortable bath water temperature and you just know that it’s too hot for the corals, so it’s not surprising that they’re bleaching but it’s heartbreaking and I really hope that the cloud cover that’s come over Magnetic Island is enough reprieve for them”.

AIMS said it’s also received reports of localised bleaching at Heron and Lizard Island.


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4 min read
Published 25 February 2020 8:46pm
By Rachel Cary


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