On Kiritimati Island, Canadian scientist Julia Baum has seen much devastation. Within a year, 90 per cent of the coral reefs she studies around the island completely died after ten months of enduring warmer water temperatures.

“The corals here had been sitting in essentially a hot water bath for ten months,” says Baum. “So, they had been stressed out more than any coral on the planet.”

But as Baum investigated the dead reefs, she found some corals that looked perfectly healthy, even after the extended bleaching event. “I couldn’t believe that any coral could survive that amount of heat stress,” she says. “What is it that’s so special, that’s so unique about these corals that healed themselves?”

To find out, Baum and her team took samples of symbiotic algae growing within the healthy corals and ran DNA testing to determine their species.

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Incredibly, the surviving corals took in different algae during the bleaching event — ones that are more heat-resistant. Baum’s discovery could have global implications on the survival of coral reefs in our rapidly warming world.

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