New laboratory studies have shed light on corals’ ability to withstand rising ocean temperatures in the Red Sea’s Gulf of Aqaba.
When corals are exposed to extreme heat, the algae that feed them and give them their vivid colors flee.The phenomenon known as coral bleaching has spread through Australia’s, the Maldives’, and the Caribbean’s reefs.
However, corals in the northern Red Sea, where temperatures are already high, have shown to be relatively resistant to coral bleaching.Researchers were able to gather coral samples from the Gulf of Aqaba to better understand their resilience and expose them to a range of extreme conditions. The physiological and genetic reactions of corals were measured at each of the stress tests.
The results of the experiments were published in the newspaper PNAS this week.
“We already knew that corals in the Gulf of Aqaba, at the northern tip of the Red Sea, were particularly resistant to higher temperatures,” lead study author Romain Savary said in a press release.
“But we wanted to study the full molecular mechanism behind this resistance,” said Savary, a postdoctoral researcher at EPFL’s Laboratory for Biological Geochemistry in Switzerland.
Currently, the temperatures Aqaba corals experience during any given top out at 27 degrees Celsius, or roughly 80 degrees Fahrenheit.At the laboratory, researchers exposure the coral samples to 29.5, 32 and 34.5 degree water temperatures. Three hours at a time and later for a whole week, the researchers turned up the water temperature.
The experiments showed both the corals and the symbiotic algal accompanying scientists’ gene-expression. The results of their tests reveal that corals in the Northern Red Sea are extremely resilient and unlike the most dramatic scenarios of sea warming, they will not lose colour.
“The main thing we found is that these corals currently live in temperatures well below the maximum they can withstand with their molecular machinery, which means they’re naturally shielded against the temperature increases that will probably occur over the next 100 or even 200 years,” Savary said.
“Our measurements showed that at temperatures of up to 32 degrees Celsius, the corals and their symbiotic organisms were able to molecularly recover and acclimate to both short-term and long-term heat stress without any major consequences,” Savary said.
The results of the test showed a complex combination of genetic changes in response to rising water temperatures among corals and their algeal residents.
“Romain’s research gives us insight into the specific genetic factors that allow corals to survive,” said study co-author Anders Meibom, head of the LGB.
“His study also indicates that an entire symphony of genetic expression is at work to give corals this extraordinary power,” Meibom said.
Although the new research can help scientists identify “super corals,” which are especially resistant to sea thermal waves and coral blanking, and potentially contribute to the conservation effort, the best way to protect coral reefs is to reduce emission of greenhouse gases and slow climate change.
The reef with coral from the northern red sea will not be an option if the planet keeps warming.
“Corals are highly dependent on their surroundings,” said Meibom. “They can adapt to new environments only after a long, natural colonization process. What’s more, the Great Barrier Reef is the size of Italy — it would be impossible to repopulate it artificially.”