Vast stretches of Great Barrier Reef coral killed by bleaching

SYDNEY — Mass bleaching has killed more than a third of the coral in the northern and central parts of Australia’s Great Barrier Reef, though corals to the south have escaped with little damage, scientists reported Monday. Researchers who conducted aerial and underwater surveys of the 1,400-mile reef off Australia’s east coast found that around 35 percent of the coral in the northern and central sections of the reef are dead or dying, said Terry Hughes, director of the ARC Centre of Excellence for Coral Reef Studies at James Cook University in Queensland state. Though bleached corals that haven’t died can recover if the water temperature drops, older corals take longer to bounce back and likely won’t have a chance to recover before the next bleaching event occurs, he said. Experts say the bleaching has been triggered by global warming and El Nino, a warming of parts of the Pacific Ocean that changes weather worldwide.