Red Sea coral reefs at risk of bleaching if the temperature drops – study

Corals living in the North Red Sea and Aqaba Bay are at risk of bleaching if the water temperature drops, new research shows. A joint collaboration between Bar-Ilan Mina University and the Everard Goodman Faculty of Life Sciences and the Eilat Interuniversity Institute for Marine Science and published in the journal PeerJ, tested corals at a lower temperature in controlled experiments to determine if they would be affected. . Whitening is the process by which coral, one of the most diverse ecosystems on the planet, is affected by a change in temperature and expels the algae that live in their tissue, making them white. Previous research by Professor Maoz Fine of Bar-Ilan University and his team has shown that coral reefs on the shores of Israel have shown a high tolerance to rising seawater temperatures compared to other reefs around the world, which could have valuable consequences with global warming and rising sea temperatures. Sea Simulator System exposes coral to higher temperatures that are expected to occur with global warming, Fine and his team initially discovered that coral did well with warmer water. However, experts predict that the Red Sea will enter a colder period, the results show how much only a slight decline can cause damage to a vast ecosystem.

“While we have repeatedly demonstrated the high temperature tolerance of coral on shallow reefs in Eilat, we wanted to test the possibility that this exceptional heat tolerance would come with the compromise of being sensitive to cold,” said Dr. Jessica Bellworthy, who did her doctoral research in the Fine department.

“Indeed, we have found that exposure to periods of cold water causes a physiological response similar to bleaching.” The team demonstrated after a particularly cold winter in Israel that even a drop in average temperature of 1 ° C can lead to a physiological response to similar stress. This proved how close the Red Sea corals are to the lower temperature threshold. Research has shown that the damaged and colder coral did not die and, in fact, returned to their previous state. They were then tested again at a higher temperature to see if the cold stress had any effect. “It was an important discovery for us to understand that even those individuals who have suffered from the cold of winter have not yet bleached at high temperatures,” Bellworthy said. Scientists have estimated that between 70 and 90% of all coral reefs will disappear by the middle of the century, mainly due to climate change and pollution, so the unique properties of Aqaba Bay coral could provide vital information to help to the conservation of other reefs around the world.