From 2015 through 2016, a warm water event caused an unprecedented 10-month heat wave on the equatorial island of Kiritimati (Pronounced Ki-ris-mass). The largest coral atoll in the world by landmass and most of the archipelago nation of Kiribati (pronounced Ki-ri-boss), the island was twice used for nuclear explosion testing (By the UK in the 1950s and the US in 1962), but that didn’t do as much damage to the coral as did the rise in temperature.
The warm water event, known as an El Niño, triggered coral bleaching around the planet, but the effects of heat stress were worst at Kiritimati.
Coral bleaching is what happens when coral release the symbiotic algae that live in their bodies and produce food for them. This causes the coral to turn white, the color of its calcium-based “skeleton.” While not immediately fatal, prolonged bleaching (anything longer than a few weeks) starves the corals to death.
What some researchers are seeing now is that some corals around Kiritimati appear to be recovering from short-term bleaching without a reduction in sea temperatures, if they’re free of other stressors, such as water pollution or acidification.
“Observing corals recovering from bleaching while still baking in hot waters is a game changer,” says Julia Baum, a marine biologist for the University of Victoria, senior author of a study into post-bleaching recovery.
“Although this pathway to survival may not be open to all corals or in all conditions, it demonstrates an innovative strategy for survival that could be leveraged by conservationists to support coral survival,” said Danielle Claar, a postdoctoral researcher at the University of Washington, who led the above study while she was a doctoral student at UVic.
Coral reefs support fisheries that provide for hundreds of millions of people, mostly those in tropical island nations like Kiribati, and generate about US$7 million annually, but they can only do so as living, thriving eco-systems.