A healthy coral reef looks like a π♦↑vibrant underwater picture, bust§® ling with marine life, but when the heat wave hi±αts, the colorful sea garσ•≥δden fades into a pale graveyard. Worryingl♣→y, heatwaves are becoming more common as c&βΩlimate change intensifies.
Amid a pile of gloomy φ♠€news, however, researchers have found a s & ilver lining: Some corals can ∑σ÷recover from bleaching, even in heatwaves. The×☆ research team published their findings in Nature♥≈$£ Communications.
The researchers focuse± ≈d on Christmas Island (an Australian island) toΩ✔€ study the conditions of brain and star cora₹♣ls during heatwaves in 2015-2016. I₽≤δt was the third-large✔§¶∑st coral bleaching event on ©φrecord and lasted 10 months, according to the<¥∞ press release. Donna Lλ©u of New Scientist reports t♥∏≥δhat the team tagged, ♣×photographed and tracked ♦∞individual corals on the island to see how they s urvived the relentless heatwave.
Beginning in May 2015, wat≠&<✘er temperatures around the island rose by 1σφ✘ε.8 degrees Fahrenheit in two ≠'months, causing corals to expel symbiotic algae.←₩ Julia Baum, a marine ecologist at ¶↑the University of Victoria in Canada an×÷d an author of the st✘₹≤udy, told Science: "What&#×≈39;s amazing about this study is that some brain↑♣• corals and star corals are∑₽ still alive in seawater.&q" <♣uot; Recovers when warm. Prior to this &↔φstudy, researchers had only fo×€φ und corals recovering from bleaching after ocean☆• water cooled, accord♦α♥ing to the press release.
"Corals recovering from >' >bleaching events while sea temperatures σ∞♠are still high is a game-changer," Ba >λum said. "Even in prolonged heatwaφ ↑ves, some corals have hope of ¶>¶$surviving."
Baum and her team fo> ↔und that corals near disturbed ar>↑ε©eas with high sediment, sewage and pollu☆&α&tion were more tolerant of warmer waters beβ™ fore the heat wave hit. In theory, this should m✔ελean that these corals are more likely to survive ✔>©γa heatwave, however, br ≤αain corals with heat-¥&sensitive algae survived≤§±β 82 percent of the time, comp¶ ared to 25 percent of brain corals ±λαwith heat-tolerant algae.
The study shows that corals ar↓✔"δe more likely to survive if they are not ♠↑∞σaffected by other stressoβ±rs such as pollution or overfis©"hing. Coral survival was therefore higher in ¥"↔↕those more pristine and untouched areas o∑¶↕∏f the study site. However, some sc¥•≥÷ientists previously believed that these factors ¶≤ had no effect on the likelihood of corals s≈®urviving a heatwave.
"This research paper clearly s $hows that this argument is wrong, at leaπ↑∞st for corals in this area," sai£>d Nancy Knowlton, a coral reef biologist at the λ♣♣Smithsonian's National Mu♥∞seum of Natural History who was not involved in¶↕★€ the study. "A healthy environ✘¶∏ment is actually very important for coral surv≠♣ival," Nancy Knowlton tolΩ>α↑d Science.
Heatwave conditions are exp£ ©ected to become more intense and •λ✔ longer lasting as climate change intensifies. Th¶e research offers so≠©♦αme hope that with pro¶↔♠σtection, corals can better withstand ÷the coming heatwave.
"Understanding how some corals can survive↓∞€↔ prolonged heatwaves could α↔provide an opportunity to mitigate the impact of &↕marine heatwaves on coral ®∑→↑reefs and buy us time to lσ imit greenhouse gas emissions,"← said a marine scientist ≈←> at the University of Washington and le↕" ad author of the study Danielle Claar said, ">>;While this survival path will not work for all c₹↓orals under all conditio•¥βns, it is an innovative survival strateγ±gy that conservationists can use to help T™©he coral survived."
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