National Geographic: The iconic reef depends on protective pulses of warm water to boost its heat tolerance. Climate change may eliminate these "practice runs."
This panoramic image reveals coral bleaching at Lizard Island on the Great Barrier Reef in March 2016. The current bleaching is the worst the reef has experienced in its history.
When waters get too hot, corals stress out and turn a ghostly white, and to survive, they must complete a marathon-like feat of endurance. Now, for the first time, new research...