A Second Major Coral Reef System Is Hit by Large-Scale Bleaching

The extensive coral reefs of the Chagos Archipelago, a collection of more than 60 small islands in the Indian Ocean, have been badly damaged by coral bleaching events over the past two years that have killed roughly 90 percent of the corals to a depth of 90 feet, according to a new survey.

The widespread reef bleaching in the Chagos Archipelago, which contains the Diego Garcia military base used by U.S. and the U.K., comes on the heels of reports that coral bleaching driven by rising ocean temperatures has caused severe damage to roughly two-thirds of Australia’s Great Barrier Reef.

John Turner, a professor at Bangor University in Wales, told the Washington Post that back-to-back bleaching events in 2015 and 2016 had severely impacted reefs across the Chagos Archipelago. He said that a recent strong El Niño weather pattern had probably contributed to coral bleaching in the region, which even damaged corals at depths of greater than 50 feet. The Chagos Archipelago is the site of a major marine reserve, and the lack of human activity in the area, other than the Diego Garcia base, has helped preserve the reefs there in a largely pristine state. Turner said  that the corals can regenerate if they are not subjected to repeated bleaching events caused by excessively warm waters.