Mass coral bleaching events are getting increasingly frequent as the oceans continue to warm, endangering coral reefs all over the world. The damage to Australia’s Great Barrier Reef has been enormous and in 2015, nearly half of Hawaii’s coral reefs were affected by a severe bleaching event.
Not all coral bleaching is permanent. Corals can sometimes recover. Some corals even seem to resist bleaching altogether. Researchers from the University of Pennsylvania studied these resilient corals to see just how effective they are in resisting the effects of climate change.
Their experiments sought to determine whether corals that seem to resist bleaching can be moved to other locations and used as the seed stock to repopulate degraded reefs.
The researchers identified coral colonies that resisted bleaching during the 2015 Hawaiian bleaching event and collected samples from them. They transplanted some of them to a second reef as well as putting other samples in laboratory tanks and simulating a bleaching event by raising the water temperature over a period of several days.
Careful tracking of the corals’ health showed that the bleaching-resistant corals stayed that way even in a new environment and under additional stress. They also studied how well the corals reproduced and found that the corals that spent time in a favorable new site before being subjected to stress demonstrated greater fitness and improved reproduction.
The study indicates that coral transplantation using colonies known to be resistant to bleaching may be an effective way to buy some time in preserving the world’s coral reefs. But global action on climate change is essential because even bleaching-resistant corals aren’t going to survive forever if ocean warming keeps increasing.
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Climate change-resistant corals could provide lifeline to battered reefs
Photo, posted November 29, 2012, courtesy of Robert Linsdell via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio.
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