Palau’s idyllic waters hide an experiment that scientists hope will save the world’s reefs from climate change-induced collapse.<\/p>\n
At an outer reef, ceramic cribs are holding thousands of baby corals growing underwater.<\/p>\n
They’re “super corals”, selectively bred to survive hotter ocean temperatures.<\/p>\n
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Star-shaped ceramic devices holding baby corals were planted last month on a section of reef damaged by a typhoon in Palau. (Supplied: PICRC)<\/p>\n
And they’re providing hope in global efforts to stop marine heatwaves from wiping out reefs.<\/p>\n
Like humans, corals are genetically diverse and some have stronger immune systems, giving them a natural advantage in surviving bleaching events.<\/p>\n
Palau’s corals appear to have those genetic gifts, having emerged relatively unscathed from marine heatwaves that have devastated reefs worldwide.<\/p>\n
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About 10 baby corals grow on each ceramic device planted on the reef.\u00a0 (Supplied: PICRC)<\/p>\n
So researchers there are selectively breeding heat tolerant corals from different species and multiple generations.<\/p>\n
They’re planting them on reefs to help ecosystems survive rising sea temperatures.<\/p>\n
“Hopefully they’ll be able to grow and we’ll be able to tell if they’re able to withstand the next coral bleaching event here in Palau,” Lauren Piot, a French-American researcher at the Palau International Coral Reef Centre (PICRC), says.<\/p>\n
A haven from climate change devastation<\/p>\n
The world’s corals have suffered through the fourth \u2014 and worst \u2014 mass bleaching event on record.<\/p>\n
The most recent bleaching event that began in 2023 has since impacted 84 per cent of reefs in 83 countries, according to the United States government’s Coral Reef Watch.<\/p>\n
But Palau, a Pacific Island nation in the western Pacific, has been a sanctuary.<\/p>\n
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Palau’s coral reefs remain in good health despite the impacts of climate change. (Supplied: Peter Mumby)<\/p>\n
Scientists see it as a glimmer of hope amid predictions that up to 90 per cent of coral reefs worldwide could disappear by 2050, if average global temperatures warm by 1.5 degrees Celsius above pre-industrial levels.<\/p>\n
While reefs overseas bear all the signs of climate change-related stress, Palau’s “have never looked healthier than they do now”, according to University of Queensland professor Peter Mumby, who has studied the country’s reefs for 20 years.<\/p>\n
“There are very few places in the world where you can say that,” he says.<\/p>\n
There are varying theories on why Palau’s corals appear to be more tolerant of rising ocean temperatures.<\/p>\n
“It’s a debate that’s still open”, says Cinzia Alessi, an Italian coral eco physiologist at PICRC.<\/p>\n
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Cinzia Alessi has studied Palau’s reefs. (ABC News: Hugo Hodge)<\/p>\n
Research suggests the corals have some ability to adapt through natural selection.<\/p>\n
In fact, Palau hasn’t experienced a mass bleaching event since 1998, while the Great Barrier Reef has experienced at least seven in that time \u2014 leaving coral cover at a 40-year low.<\/p>\n
Watch the episode<\/a><\/p>\n Journey to Palau with The Pacific where scientists are racing to use the nation’s reefs to save corals around the world from climate change.<\/p>\n Coral bleaching happens when the water gets too warm and stressed coral expel the algae living in their tissue.<\/p>\n They usually recover, but more frequent and severe heatwaves are killing entire reefs.<\/p>\n Palau’s ‘super corals’ raise hope<\/p>\n As Palau’s corals have emerged as climate change survivors, the PICRC has become a leader in global efforts to help reefs adapt to warming temperatures.<\/p>\n It uses a method called “coral assisted-evolution” \u2014 where scientists breed heat-resistant “super corals” and plant them on the reefs.<\/p>\n Multiple generations of selectively bred, heat-tolerant corals grow in a nursery off Palau’s coast.\u00a0 (Supplied: Lauren Piot)<\/p>\n They use different species of coral from multiple generations to maximise genetic diversity, which gives them the best chance at surviving warming ocean temperatures.<\/p>\n The PICRC recently planted 1,600 of them with funding from the Great Barrier Reef Foundation, after years of ground-breaking research led by Newcastle University.<\/p>\n “Seeing those corals actually be heat resilient is going to be really incredible and hopefully we’ll see that soon,” Ms Piot says.<\/p>\n Lauren Piot looks forward to seeing the results of the coral-assisted evolution project. (ABC News: Hugo Hodge)<\/p>\n For Palau’s 18,000 people, the ocean is more than a resource to exploit.<\/p>\n It’s a living thing that forms part of their identity, and most children grow up playing in the country’s coral reefs.<\/p>\n Like many Palauans, conservationist Ann Singeo can’t remember when she learned to swim.<\/p>\n Palau conservationist Ann Singeo leads coral restoration efforts across the country.\u00a0 (ABC News: Hugo Hodge)<\/p>\n “You’re basically thrown into the water as you start to walk,” she says.<\/p>\n Now she leads coral restoration efforts up and down the country, monitoring the “super reefs”.<\/p>\n “We think of the ocean as an entity with a spirit,” she says.<\/p>\n Palau’s corals have escaped the bleaching events that have harmed reefs around the world. (Supplied: Peter Mumby)<\/p>\n Spread over 300 islands, Palau has a unique geography and vast atolls that create the perfect conditions for biodiverse marine life.<\/p>\n The country has strong environmental regulations and its small population helps limit pollution, while international visitors entering the country must sign a pledge to protect the rich ecosystems.<\/p>\n “Palau is really a place where scientists want to come because it’s quite pristine and you can take out some of the disturbances that you can observe in other reefs,” Dr Alessi, from the PICRC, says.<\/p>\n A section of reef in Nikko Bay, Palau. (ABC News: Hugo Hodge)<\/p>\n But 4,000 kilometres away, on Australia’s north-west coast, another so-called “lucky reef” bears a warning for Palauans looking to conserve their marine environment.<\/p>\n Molecular ecologist Kate Quigley is running coral-assisted evolution experiments on Ningaloo Reef, which until recently had also escaped many of the worst impacts of climate change.<\/p>\n WA’s ‘catastrophic’ bleaching event<\/a><\/p>\n In Western Australia, the damage to coral reefs including the World Heritage-listed Ningaloo has eclipsed any previous bleaching events.\u00a0<\/p>\n Ningaloo’s reefs have much in common with those in Palau.<\/p>\n “They are in environmental conditions that are buffering some of that heat,” she says.<\/p>\n “We thought that Ningaloo was a reef like that.”<\/p><\/blockquote>\n But it fell victim to the recent global marine heatwave, suffering a “catastrophic” bleaching event, its worst on record and the first in more than a decade.<\/p>\n “Ningaloo shows us this year that it’s only a matter of time for even those lucky reefs,” Dr Quigley says.<\/p>\n Australia is now investing big in coral-assisted evolution to help its reefs survive marine heatwaves.<\/p>\n “This kind of selective breeding work has really started to ramp up in the last few years, mostly because people have seen their [other] restoration efforts fail,” Dr Quigley says.<\/p>\n Buying time for the world’s reefs<\/p>\n The work is slow going, and PICRC’s corals take as many as six to eight years to grow into big colonies.<\/p>\n Their research shows it is feasible to use selectively-bred “super corals” for conservation.<\/p>\n However, there are doubts they’re being deployed fast enough and can withstand increasingly severe marine heatwaves into the future.<\/p>\n “When I talk with other scientists we know that we are not there yet,” Dr Alessi says.<\/p>\n “It is feasible, it’s a lot of work, but we need more people doing this because we are running out of time.”<\/p><\/blockquote>\n Coral reef managers are focused now on scaling up these methods and making it more cost effective to address the urgent crisis.<\/p>\n In Australia, the Great Barrier Reef Foundation has an ambitious goal of planting 10 million heat tolerant corals annually across 100 priority reefs by 2030.<\/p>\n A coral spa at the Palau International Coral Reef Centre, which is leading efforts to breed “super corals”. (ABC News: Hugo Hodge)<\/p>\n Modelling from Newcastle University and the University of Queensland shows natural selection could save corals if global warming is limited to a maximum of 2C.<\/p>\n But last year was the hottest on record with temperatures exceeding 1.5C<\/a> and the world has already lost 30 to 50 per cent of its coral reefs.<\/p>\n It’s not science fiction to imagine a future where Palau’s corals are transplanted onto reefs around the world.<\/p>\n<\/p>\n
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