coral reef

At first, Dan Harrison didn’t think the idea would be taken seriously. But as situations become dire, crazy-sounding ideas can start to sound … pretty good. His plan is “cloud brightening,” and frankly, it reads like the premise of a sci-fi movie.

A geo-engineering concept that could literally change sunny skies to overcast ones sounds far-fetched, but to save the Great Barrier Reef, weather hacks like his may be required. It’s just one of the creative methods scientists are trying in order to save some of the world’s most sensitive and important living organisms.

Harrison, a research fellow at the Sydney Institute of Marine Science, saw that the Great Barrier Reef was still suffering from the one-two punch of back-to-back mass bleaching events in 2015 and 2016. Warm water kills coral polyps, leaving behind a white skeleton that’s been stripped of living tissue, so mass die-offs are often called “bleaching” events.

The massive coral system off the coast of Queensland, Australia, covers an area of 133,000 square miles and is a wonder of the natural world, but warming water temperatures and other factors that remove organic life have killed large portions of the Great Barrier Reef, as Australian researchers reported in the journal Nature last year.

And while the situation may look dire, Harrison is part of a growing movement of scientists who are working on creative, innovative solutions for the crisis facing the world’s coral reefs.

Bleached Coral reefs dead

“It’s absolutely shocking to dive on a reef that you know well and to see it turn white in the space of a week.”

The past few years have not been kind to the world’s coral reefs. Climate change is warming the world’s oceans, creating more mass bleaching events. A single heat wave in 2016 killed more than two-thirds of the corals in 29 percent of the reefs that make up the Great Barrier reef. In the analysis of the die-offs, scientists found a clear correlation between water temperature and bleached coral.

Climate change is just one threat facing coral reefs, though. Boats — large yachts and cruise ships — regularly damage reefs with their anchors and chains, and chemical residues in the water also threaten the health of coral. The chemicals oxybenzone and octinoxate (sometimes also called octyl methoxycinnamate), which are commonly found in sunscreen, are also thought to contribute to coral bleaching. In July, the state of Hawaii banned sunscreen that contains a oxybenzone, chemical harmful to coral reefs.

Despite the demonstrated harm caused by these chemicals, scientists still aren’t exactly sure how they hurt the coral.

“The response of corals may be related to disrupting a specific signaling system, or it may be a more general stress response,” Ann Tarrant, Ph.D., a biologist at Woods Hole Oceanographic Institution who studies the effects of stress on coral physiology, told Inverse in July. But even without knowing exactly what’s going on, scientists are certain enough that Hawaii imposed the ban. Donna Mercado Kim, a Hawaii state senator who co-sponsored the bill, called it “a first step to help our reef and protect it from deterioration,” reported The Spokesman-Review.

While we’ve heard a lot more about the challenges facing coral reefs in recent years, the issue has been building steam for decades. And it’s not just limited to the Great Barrier Reef.

Scientists and politicians have to get inventive to preserve the reefs if they want to save them against overwhelming odds. Here are three ideas being executed now.

A before and after image of coral bleaching and later dying in March / May 2016, at Lizard Island on the Great Barrier Reef, captured by The Ocean Agency / XL Catlin Seaview Survey / Richard Vevers & Christophe Bailhache.

1. D.I.Y. Clouds

Harrison’s cloud brightening idea sounds incredibly simple: Create clouds to block the sun above the reef to keep water temperatures from getting too hot. The execution is slightly more complicated: Large nozzles spray sea water into the air, and large fans propel the water even higher. As the water rises, it evaporates, and the salt remains in the stratosphere. Water vapor condenses around those salt particles, forming clouds, and the Great Barrier Reef receives human-made cloud cover.

The project has now gained momentum, as well as the attention of the Australian government.

Needed first are feasibility studies, government funding, and bespoke equipment. Harrison and his colleagues are undeterred: They’re pushing forward, as they have been for the last few years.

“We can show that if cloud-brightening works, then you can really cool the waters of the reef down enough to mitigate nearly all the bleaching at the moment, but obviously progressively less as climate change becomes worse,” Harrison tells Inverse.

The group is also consulting with other teams working on cloud brightening, but the project is still in its feasibility phase. The Australian government has included the project in its Reef Restoration and Adaptation Program (RRAP), a multi-institution project, the mission of which is to preserve the Great Barrier Reef for the future.

The Australian government has granted $6 million to the RRAP for a “scoping phase” that will inform how an additional $100 million will be allocated in 2019. If that sounds like a lot of money, just remember that the Great Barrier Reef provides irreplaceable ecosystem services and contributes $6.4 billion to Australia’s economy. And it’s not alone in facing serious threats.

This diagram makes cloud brightening look as simple as assembling Ikea furniture.
This diagram makes cloud brightening look as simple as assembling Ikea furniture.
Dan Harrison
Erinn Muller in her lab.

Coral researcher Erinn Muller, Ph.D. says coral reefs don’t easily bounce back from loss events like disease outbreaks or bleaching from hot water. As the program manager and science director of the Elizabeth Moore International Center for and Restoration in the Florida Keys, she says the decline has gone on for decades.

“We’ve seen coral cover loss being well-documented for the last 50 years or so,” tells Inverse. “Transitioning from 50 percent of the reef being covered by living corals, now we’re down to about five percent coral cover.”

A disease outbreak is wreaking havoc on reefs in the Florida Keys, sloughing the living tissue off the coral and leaving behind bare skeletons in a matter of weeks. It’s been occurring for about four years now, gradually spreading throughout the reefs surrounding the Keys.

“It’s hard to take,” she says. “There’s so many threats the reefs have to deal with on a daily basis that adding another very large, very detrimental effect to the reef has been really hard to stomach.”

“Hopefully we are setting a precedent that whenever there’s an outbreak, instead of just monitoring and studying it to death, as a group of scientists and collaborators, we’re taking action to try and stop it.”

Despite the grim situation, Muller is heartened by cooperation to solve the problem: A consortium of experts in Florida has assembled to share information on pathology, how the disease is spreading, and active interventions. In 15 years of research, she’s never seen people mobilize like this.

“We literally talk once a week to provide everybody with updates on what we’re all studying,” she says. “I’m happy and grateful to be a part of that in this disease outbreak, as well as in being a model for anything that happens in the future.

Muller, though, is looking for a solution that can be applied on a much larger scale, one that would benefit the entire ecosystem.

This video B-Roll was taken in the Lagoon of Ermitage, Réunion Island, in the Indian Ocean during the coral bleaching event in April 2016

This past April, an article published in the journal PLOS Genetics illustrated how a team of researchers found that corals in the Great Barrier Reef may actually be adapting to keep up with warming waters — and they could continue to do so in the future.

Mikhail Matz, Ph.D., an associate professor of coral genomics at the University of Texas, led the research.

Matz and his colleagues demonstrated in a 2015 paper in Science that heat tolerance is a genetic trait that can be passed down from generation to generation.

Since coral populations carry so many variations of genes, some genes will inevitably help the coral withstand new and strange environmental conditions.

Computer modeling suggests those genes that can adapt to heat could spread throughout an entire population in just a few generations.

“People do not typically realize that evolution can be efficient and rapid,” Matz tells Inverse.

If the genetic models turn out to be accurate, coral’s adaptation could keep pace with climate change through the rest of the century. It’s even possible that the corals in the Florida Keys could develop a resistance to the diseases that are threatening them.

Mikhail Matz

“It looks like every prediction about the future will almost entirely depend on how much corals will be able to adapt,” Matz says.

2. Genetically Modifying Coral to Survive a Hotter World

Matz’s research on the natural adaptive abilities of corals leads to the obvious question of genetically modifying corals, or at least speeding up the process of evolution. Enter so-called “assisted evolution,” in which lab-grown corals are subjected to harsh conditions like warm or acidic waters.

The corals that survive harsh conditions considered promising sources of future stock for revitalizing depleted reefs. Many researchers aren’t ruling it out — but Matz isn’t convinced it’s necessary.

“Everybody’s asking this question, but the main message from other papers is that you don’t need to do this,” says Matz.

Based on his research, Matz believes that assisted evolution, or CRISPR-Cas9 genome editing, or any other method that would speed up the rate at which coral adapts to warming and acidifying waters is unnecessary because of coral’s immense capacity for rapid and efficient natural evolution.

“It’s already there, it just needs to play out,” he says. “You don’t need to create anything new. There are resilient corals already out there, they just need to spread their genes to other populations.”

Erinn Muller

Matz says it could take decades to perfect the process of genetically modifying coral so it can stand up to hotter, more polluted waters:

“We don’t know which genes to modify, we don’t know which traits to modify. Everybody thinks it’s resistance to heat, but what if it’s not? What if it’s resistance to temperature range between winter and summer? What if it’s resistance to disease, despite being heated up a little bit? You can not really guess this stuff.”

Despite the ease with which CRISPR-Cas9 allows scientists to edit DNA, they still need to know what they’re editing. Research has shown that finding a suitable gene editing target is not so simple. Most traits don’t have a single gene associated with them. Instead, there’s usually a set of genes that encode for specific characteristics.

In other words, scientists can’t just go into the genetic code for coral and switch out a “Dies in Hot Water” gene for a “Loves Hot Water” gene. Matz and his team found this out the hard way.

Their paper published in April in the Proceedings of the National Academy of Sciences, shows that even though it’s possible to genetically modify coral using the versatile CRISPR-Cas9 gene editing tool, some traits are encoded by multiple genes, making it much trickier to alter even simple physical traits.

The traits that were successfully altered persisted through several cell cycles, but without creating persistent genetic changes to populations, the changes would not stick around long enough to alter future generations of wild corals.

is coral a plant or animal

3. Microsoft Artificial Intelligence Makes Coral Mapping Lightning Fast

Off the coast of Indonesia’s Sulawesi Island, a Microsoft-backed project that uses 360-degree cameras and artificial intelligence to survey reefs is helping scientists map and analyze corals more quickly.

“The use of A.I. to rapidly analyze photographs of coral has vastly improved the efficiency of what we do,” Emma Kennedy, PhD., a benthic marine ecologist at the University of Queensland, said in a statement. “What would take a coral reef scientist 10 to 15 minutes now takes the machine a few seconds.

“The machine learns in a similar way to a human brain, weighing up lots of minute decisions about what it’s looking at until it builds up a picture and is confident about making an identification.”

The project is only in its early stages, but the researchers involved hope it will yield new insights into better reef management and preservation practices.

In fact, the project already showed that their survey areas bounced back more quickly than expected from a mass bleaching event.

Coral Reef A.I. Artificial Intelligence

Save the Future!

The future for corals depends on our ability to slow the pace of climate change. The incredible capacity of coral to evolve and adapt to changing ecological conditions may be the only thing allowing reefs to hold on at the moment.

Scientists like Harrison, Muller, and Matz who are working to help stem the worst effects of coral reef loss are making progress, but without curbing the rate of carbon emissions, they’re just slowing down the inevitable result of climate change and environmental degradation. It’s going to take more scientists like them who are willing to go out on a limb to pursue inventive ideas.

“I’m very confident that corals will not be extinct within the next hundred years, but I have no confidence at all that they will be able to hold on if we don’t do anything about climate change,” says Matz.

“We just need to reduce carbon emissions and stop the global warming trend. If we do this within 100 years, corals will be saved.”

This slow-growing Porites coral colony is one that bleaching has hit particularly hard. Slow-growers like this will have a harder time recovering under rising sea temperatures.