As coral reefs suffer due to the climate crisis, scientists in Israel have discovered some hope: corals in the Red Sea that are highly resistant to heat. Coral reefs are some of the most diverse ecosystems in the world. Right now, the effects of climate change are devastating the world’s reefs. Experts estimate that half of the world’s coral reefs have died within the past three decades, and that all existing reefs may be eliminated by the end of the century.
However, coral reefs in the Red Sea seem to be “content” with the increasing temperatures, as Anders Meibom, a researcher with the Institute of Earth Sciences at the University of Lausanne, puts it. His team conducted an experiment to test the heat resilience of the coral. “We were heating the water one degree above the summer maximum temperature,” said Meibom. “On the Great Barrier Reef, after a couple of weeks of that [the coral would] start dying.”
But the coral reefs taken from the Gulf of Aqaba, a trench of water surrounding Jordan, Israel, Saudi Arabia, and Egypt, did not. Even when the marine scientists continued to raise the temperature, the coral in the experiment at the University of Eilat survived as much as 7℃ past the summer maximum. Some coral actually appeared to do better in the warmer waters. In stylophora pistillata, the symbiotic algae that provides coral with oxygen and waste removal showed a 51 percent increase in productivity.
These results confirmed many reports from divers in the Gulf of Aqaba and the Red Sea. Despite temperatures in the area rising at the same rate as the rest of the globe, coral species there have never suffered a bleaching event. Coral bleaching occurs due to abnormally high ocean-surface temperatures and increased acidification, both consequences of global warming. Coral turning white — the result of symbiotic algae leaving the coral — is a clear sign that corals have become severely vulnerable to heat and disease.
Scientists believe evolution contributes greatly to Red Sea coral’s heat tolerance. “This population of corals [in the northern part of the Gulf of Aqaba] migrated into the Red Sea system from the south where the temperature of the water is — and always was — high,” Meibom said. Over thousands of years, some of these corals migrated north to where they now live at lower temperatures, but they kept their capacity to live at higher temperatures.
More research has led scientists to determine that a large range of corals along the 2,500-mile stretch of the Red Sea reef are uniquely resistant to the climate crisis. At the current rate the Earth is heating up, the Red Sea reef may have a chance at withstanding the rising temperatures of the next few decades.
As one of the last coral reefs to survive, the Red Sea reefs could potentially “form a refuge where it becomes one of the few remaining reefs with full ecosystem function,” said Andréa Grottoli, a professor in the School of Earth Sciences at Ohio State University. “It could serve as a model for restoration once climate change stress is mitigated and we start being able to actually reintroduce coral…[serving] as a model for what a normal reef might look like.”
But in order for it to serve as a possible model in the future, the reef will need to be protected from pollution, overpopulation, fish farming and agricultural runoff. When Fine introduced excess nutrients and heavy metals to the corals in the experiment, the coral became compromised and lost its resilience. This led scientists to determine that the coral’s heat resilience may not be enough. “If we are to secure the Gulf of Aqaba and the northern Red Sea as a coral reef refuge, we have to remove the local stress,” said Fine.
Fine, Meibom and several other scientists and diplomats are calling on UNESCO to declare the Red Sea reef as a Marine World Heritage Site to guarantee its protection from local threats. However, lack of funding, travel restrictions as a result of COVID-19 and the region’s tense politics are slowing down progress. Protecting the coral reefs from threats will require at least four Middle Eastern governments — some which do not recognize each other’s existence — to work together. “No one country can protect it alone,” said Olivier Küttel from the Swiss Federal Institute of Technology in Lausanne. “Egypt can do well, but if Saudi Arabia, Israel or Jordan do poorly, they can very rapidly destroy the whole ecosystem,” he said.
The strained relations between the countries and COVID-19 have also delayed an ambitious research expedition. Fine, Meibom and their team plan on sailing from the north to the south of the Red Sea to investigate further reasons behind the coral’s resilience and a glimpse into warmer waters. “When you move south in the Red Sea, you’re essentially sailing into the future in terms of coral resilience to climate change,” Meibom said, “Everything gets warmer and warmer.”
The expedition would require research permits from countries that border the Red Sea, including Djibouti, Egypt, Eritrea, Israel, Jordan, Saudi Arabia, Sudan and Yemen. The countries share a common interest in corals, and if the reef is harmed, so are the ecosystems and economies that depend on it. Fine and Meibom are optimistic that people across the region can put politics aside and band together to protect the Red Sea reefs. “Reefs recognize no political borders,” said Fine. “What happens in one reef will affect the rest of the reef on the other side of the border.”
“This is probably our last chance [globally] at saving a major reef ecosystem that could be well-functioning 50, 60, 100 years from now,” Meibom said. “It’s a treasure. And it has enormous impacts on the region. So everybody has a common interest in preserving it — not only in the Red Sea, but for humanity.”