Great Barrier Reef restoration technologies

Cosmos Investigation: Potential reef “saviours” (part 2 of 3)

What’s really happening on the reef? A special three part series. 

Robot-deployed supercorals are going to rescue the reef!  No, wait – it’s giant sea-spray canons that’ll save it!  Hang on – didn’t I just see an article in The Guardian about a pioneering coral nursery producing its first babies to help save the reef? 

Confusion reigns in the daily news cycle, with the Great Barrier Reef apparently being saved all over the place.  So how do you get your head around what actually has potential to help our imperilled reef – or whether these stories are at best false hope; at worst a greenwashing distraction, delaying action on emissions?

In this second part of my special investigation, I endeavour to sort through potential reef “saviours” – and I confess to getting one of my cynical pre-conceptions kicked over in the process.

The problem most reporting fails to come to grips with is scale; the sheer mind-blowing size of the Great Barrier Reef, which is as big as Italy. 

The problem most reporting fails to come to grips with is scale; the sheer mind-blowing size of the Great Barrier Reef, which is as big as Italy. 

Emblematic of the scale problem is recent press coverage of the not for profit Reef Restoration Program, which announced its coral nursery gave birth for the first time.  I’m not trying to single them out because they contribute something really important which I’ll come to later, but their beautiful milestone involved a few thousand corals hung on just – wait for it – 50 tree-shaped wire frames. 

Dr Terry Hughes, coral researcher “grandee” and one of the most outspoken critics of restoration programs as a dangerous distraction from emissions reduction, sums up the problem in a tweet:  (Nov 16) The #GreatBarrierReef is the size of 70 million football fields, and globally in the last 50 years we’ve restored maybe….two..      

“I really worry about the “clever scientists will fix this” narrative,” he tells me bluntly. “Because we can’t.”

So what do the “clever scientists” working on restoration technology think? 

“I don’t know any scientist who thinks we’re ok if we go past 2.0 degrees warming,” agrees Dr Dave Wachenfeld, Chief Scientist of the Great Barrier Reef Marine Park Authority.  “But we might succeed at 1.5 degrees – 2 degrees.  And that’s where the tools we are developing might make a difference.”

Dr Wachenfield triages their approach.  Number one is emissions reduction – unless we stabilise temperatures corals won’t survive.  Two – traditional management – protecting coral reef from other threats like water quality, overfishing and arch-nemesis Crown Of Thorns (covered in part 3 of this series in the next issue of Cosmos Weekly).  Three: emerging technologies and R and D. And that’s where the Reef Restoration and Adaptation Program, or RRAP, comes in. 

Jonica newby sitting on a rock at the beach
Jonica Newby. Credit: supplied

Involving more than 300 scientists and engineers across universities, research institutions and industry, RRAP was established in 2019 to develop cutting edge technologies with the potential to work at industrial scales.  “This is the globally leading program,  says Dr Wachenfeld, “hand on heart.”

After talking with a number of scientists, I’ve decided to focus on the top three technologies that Dr Wachenfeld and others think have real potential.

“Larval harvesting is most useful where local reef reproduction has collapsed.”

Professor Peter Harrison

First is Larval Harvesting.  I catch its instigator, Professor Peter Harrison, on his way to Hook island for the annual spectacular that is mass coral spawning.  As a young scientist Harrison helped discover the phenomenon back in the 80s. But soon after, he witnessed his first mass bleaching – and it made him wonder if we could harvest these spawn to restore dead corals.

His process involves scooping coral spawn into inflatable “nursery pools” moored temporarily near a reef.  The spawn develops into coral larvae, which, after 5 – 7 days are ready to settle and be deployed.  His largest experiments so far have been in the Philippines, where coral reproduction had completely collapsed, leaving degraded, algae covered rubble.  By seeding with larvae from coral that survived recent bleachings, they achieved new coral growth – potentially on a hectare wide scale.   Nine years on, they are on the fourth generation of reproduction from that first site.  He’s since trialled it on nine sites on the great Barrier Reef.

“Larval harvesting is most useful where local reef reproduction has collapsed,”  he says.

Harrison sees it being used in these extreme situations to create reproductive “hubs” which can seed coral larvae out into the surrounding areas.

“My dream is we train members of the community to do this,” he explains. “Even if just 1% of all the boats on the reef take it on, it can make a difference across the whole area.” 

Acropora tenuis colonies growing from larval harvesting on the great barrier reef.
Acropora tenuis colonies growing on a larval enhancement plot three years after settlement. *Indicates colonies grown from settled larvae, **indicates the large colony derived from fusion of 31 small colonies grown from settled larvae. Credit: Adapted from Cruz and Harrison, 2017, Scientific Reports, DOI: 10.1038/s41598-017-14546-y

“Larval survival is a bit hit and miss in nature”, he admits. “Many die. But those that survive are likely better adapted to the changing environment.  I see it as one tool in a toolbox.” 

This is where Dr Line Bay comes in, and the second of the potential solutions: Aquaculture

“We’ve overcome the bottleneck of larval survival,” Bay says, “but the other advantage is we can control the “who”.   We can select more heat tolerant larvae. Sure, we can’t grow the 600 plus species of coral on the wild reef, but we are aiming for 20 to 40 species to provide a good functional spread.”

The corals are grown in an aquaculture facility, then placed in special devices they’ve invented, which protects the little corals as they grow.  It’s analogous to aerial planting of seedlings for re-forestation.  Bay’s vision is that in 15 years there may be a network of coral breeding facilities up and down the coast.

But doesn’t this all sound rather – expensive?  Aren’t we back to that scale-ability problem?

“This has been designed with an industrial and automation lens. The devices come in flat sheets and stack well.  Our aim is to get to 10 to 100 million corals deployed per year at a cost of around $1 per surviving coral.”

“We don’t want to get to the point of the Caribbean or Florida where many corals completely collapsed.  We need to be preparing now.”

But I’m still struggling a bit mentally with the scale and the cost – even at $1 per coral.  The Great Barrier reef is much bigger than the Caribbean – Terry Hughes says we’d need trillions of coral.

“We don’t want to get to the point of the Caribbean or Florida where many corals completely collapsed.  We need to be preparing now.”

Dr Line Bay

“Call David Mead”, says Line, and gives me his phone number.

“A hundred million a year for the Great Barrier Reef is chump change,” says Mead, coming in strong.  “I’m used to dealing with projects in the billions! We spend that on a stretch of road – why wouldn’t we spend it on a structure as economically and psychologically important as the reef?”

David Mead led the establishment of RRAP.  He’s an engineer, who previously worked for the Snowy Hydro scheme and says, it’s too late in his life to bother with things that don’t have potential. 

To my surprise, the third top “tool” in the toolbox Mead nominates is one I originally dismissed as outlandish—Cloud Brightening—suggested by another engineer and colleague, Dr Dan Harrison.

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“When Dan first walked in my door I thought he was crazy,” says David Mead. “But when I looked it, I gradually thought this can work. And it’s the least risky of the strategies – the only thing that can prevent coral bleaching.”

As reported in Cosmos earlier this year, cloud brightening makes clouds subtly more milky so they reflect more light, reducing solar radiation by somewhere between five and ten percent.

It’s still very much experimental – ten years away from anything practical even if it survives the R and D process.   But essentially big spray guns, like snow-making machines, project nanoparticles of saltwater into the air. The particles are so small they float upwards, attracting tiny water droplets to form, which turn the clouds slightly milkier.

“My guess is we’d be deploying a hundred or so of these on pontoons across the reef, running full time several months of the year”, says David Mead. “I’m not betting the farm on it. But when we modelled whether it would have made a difference during previous bleaching events, it did.”

Some scientists are still sceptical.  But several I trust have real hope for this technology, and convinced me to put it in this article.

“We can’t “save” the reef. We can’t keep it the same. The deeper we go into climate change, the more dramatically it changes. But our role is to develop tools to preserve as much of the value and function of the Great Barrier Reef as possible.”

David Mead

So where does community reef restoration come in – the kind of small scale “coral gardening” practiced by the Reef Restoration Foundation? 

“It’s important you don’t belittle what they do because these community engagement groups are essential,” says Bay. “As we develop better and better tools, these are exactly the groups we need to deploy them. They’ll be the conduit.”

“We can’t “save” the reef,” says David Mead. “We can’t keep it the same. The deeper we go into climate change, the more dramatically it changes. But our role is to develop tools to preserve as much of the value and function of the Great Barrier Reef as possible.”

“It’s a fine line between giving false hope and giving enough hope not to fall into despair,” says Peter Harrison.

“Don’t let the people who say it can’t be done get in the way of those who are doing it,” adds Bay.  “If we fail, at least we tried!  At least we did everything for the reef that we could.”

Read the third and final part of this series in next week’s Cosmos Weekly on December 9.

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