The Great Barrier Reef bears third mass bleaching in five years

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According to Science News Magazine, the Great Barrier Reef has once again been bleached. This bleaching is the third major bleaching this region has faced in five years, the last being in 2016 and 2017. Results from a flyover show that sixty percent of the coral in the area were affected. Twenty-five percent of coral are severely damaged while the other thirty-five percent of affected coral have less extensive bleaching. “This is the second most severe event we have seen, but it is by far the most widespread,” says marine biologist Terry Hughes, director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University in Australia. The bleaching spread through all areas of the Great Barrier Reef, affecting the northern, middle, and southern parts. ~

According to the National Ocean Service, “when corals are stressed by changes in conditions such as temperature, light, or nutrients, they expel the symbiotic algae living in their tissues, causing them to turn completely white.” The specific cause for this bleaching would be the increase of the surface temperature of the ocean this year. Australia’s Bureau of Meteorology claimed that February had been the warmest temperature for the surface of the ocean since records began in 1900. This increase of temperature caused the corals to eject most of the symbiotic algae that give the reef nutrition and its color. This ejection of the algae will cause some of the corals to die, Science News Magazine claims. ~

These bleachings are taking place more often and leaving less time for the reef to recover in between. “Those gaps [between bleachings] are important because that’s the opportunity for corals to rebound and make a recovery…. It takes about a decade for the fastest-growing corals to fully rebound,” claimed Hughes. According to predictions by Hoegh-Guldberg, who studies coral reefs at the University of Queensland in Brisbane, Australia, if this trend continues, in about ten years there will not be much left of the Great Barrier Reef. Hughes claimed, “Optimistically, if temperatures don’t rise too much more, we’ll still have a reef, but it’s going to look very different” (Science News Magazine). ~ 

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