Record levels of heat in the ocean are causing a worldwide mass bleaching event on coral reefs. It's the second one this decade, where the delicate skeletons of corals turn a ghostly white.
With mass bleaching only expected to get worse as the climate keeps warming, coral scientists are urgently searching for ways to help reefs endure. Bleaching can kill corals, putting some of the most diverse ecosystems in the world at risk. So scientists are homing in on how bleaching happens.
