Why Global Citizens Should Care
Coral reefs, like forests, are integral to the health of ecosystems and human communities. The United Nations calls on countries to protect at least 30% of marine and land environments by 2030. You can join us in taking action on related issues here

The bacteria in our gut help us think, digest food, regulate hormones, and expel pathogens.

Shouldn’t the same go for animals and plants? 

A team of coral reef researchers at the Red Sea Research Center in the King Abdullah University of Science and Technology (KAUST) has been exploring this question for the past several years. They recently tested whether optimizing the bacteria of coral could protect it against the stress of rising temperatures.

What they found could transform coral reef conservation worldwide. 

In fact, the team discovered that increasing the presence of native Beneficial Microorganisms for Corals (BMCs) improves the survival rate of coral suffering from coral bleaching by 40%. These coral are also better able to recover from bleaching events and develop future heat tolerance that could potentially allow them to better survive in the years ahead.

“We’re making super corals for thermal stress,” Raquel S. Peixoto, the lead researcher on this project, told Global Citizen. “In all of these cases, we’re trying nature based solutions — things nature has been doing for thousands of years — and we’re trying to speed up the process. We’re accelerating the process of selecting the best [coral].” 

Her team is literally in a race against time. Already, coral are dying at an alarming rate because of rising ocean temperatures and marine heat waves. By 2050, scientists estimate that 90% of current coral will be wiped out or threatened

The ocean absorbs the majority of the heat trapped in the atmosphere by greenhouse gas emissions. As this heat gets distributed, fish migration patterns are changing and plant life is being disrupted. Coral, in particular, are highly sensitive to temperature spikes. 

Prolonged exposure to heat can stress coral so much that they expel the symbiotic algae that give them color and nourishment. This is known as coral bleaching. Across the ocean, once vibrant reefs are turning bone white. Recovering from a bleaching event is an arduous process that can take years — think of a community recovering from a devastating hurricane. The problem, however, is that reefs are being exposed to bleaching events on a nearly annual basis. So just as a reef begins to recover from the previous season’s heat wave, another arrives to erase the progress that has been made. 

That’s one of the reasons why the coral in the Red Sea are uniquely capable of yielding secrets that can help conservationists. Because the region is unusually warm, the native coral are abnormally heat tolerant, Peixoto said. 

“We think it’s an evolutionary process,” she said. “These coral have been selected for going through some thermal impact and exposure to higher temperatures. This process and the local conditions have selected coral that are quite remarkable in their ability to cope with stress. They’re more adapted and react better to these impacts.”

But even these coral are reaching their breaking point, she said. 

Peixoto, who got her PhD in microbiology, decided to study the microbial population of coral in the Red Sea because of the profound capabilities of bacteria. Her team found that naturally-occurring microbes help coral withstand and recover from heat stress. So the team increased the amount of these microbes on select coral in a laboratory setting and found that they acted as a sort of armor.

While coral with enhanced microbiomes haven’t been released into the ocean, Peixoto said that doing so wouldn’t cause adverse effects. After all, the bacteria that’s being maximized is naturally found on reefs in the Red Sea. 

“What I think is overlooked is we’re not looking at pristine ecosystems anymore,” she said. “The first thing people ask is, ‘Aren’t you going to change the natural diversity of bacteria?’ What I say is, it’s already been changed by impacts and in the wrong way."

“These reefs are severely affected and it’s common to see some pathogens overgrowing the beneficial microbes,” she said. “We are not talking about changing something that is good and pristine, but something that has been changed in a bad way. We want to restore the original microbiome or replace it with a beneficial microbiome that is more beneficial to this environment.”

Her colleagues in Brazil have found similar results with local coral. Other coral researchers are trying to isolate and propagate coral that survive bleaching events, while others are genetically modifying coral to improve heat tolerance. Peixoto said that her technique can theoretically be applied to coral in different ecosystems facing other kinds of threats. 

“We’ve been developing personalized medicine [for humans],” Peixoto said, referring to the growing field of immunotherapy. “It has to be very tailored, and depending on your age and diet, you have better options.”

“We’ve been thinking about customized medicine for coral,” she added. “Depending on the reef, there will be different impacts. It’s not just about CO2, it’s also overfishing and oil spills, and you can think of tailored solutions [for these threats]. It sounds complicated but it’s not.”

Perhaps microbes that protect against heat stress can be introduced to coral in other parts of the world, she said, or different coral reefs can be studied for their own blend of super microbes. These kinds of intervention can even be extended to other forms of wildlife, she said. 

“By using this type of technology, by testing it, we’re acquiring knowledge about it,” she said. “We can share this knowledge with other researchers, and they can come up with their own local microbial solutions.”

But she stressed that this approach is simply a stop-gap measure to prevent mass extinction. The best way to save coral — and all biodiversity for that matter — is for humans to stop causing so much harm to the planet, she said. 

Phasing out fossil fuels will reduce greenhouse gases in the atmosphere, which will prevent ocean temperatures from rising exponentially. Stronger fishing regulations can prevent overfishing, bycatch, and ghost fishing. Regulations around pollution, meanwhile, can stop dangerous chemicals from entering the ocean. 

Without these transformations, then it doesn’t matter if certain bacteria improve coral resilience; there won’t be any coral reefs left to protect. 

“We are dealing with the local impacts and the global impacts,” she said. “Together they are like a bomb. We have a closing window of opportunity, only about 10 years, to protect them or not, and, now, it's about making all the efforts we can.”


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