Bleached Coral Is Not Dead, but It Is in Danger

White coral looks like a skeleton, but bleaching is not the same as death. NOAA’s National Ocean Service explains that when corals are stressed by changes in temperature, light or nutrients, they expel the symbiotic algae living in their tissues, which causes them to turn completely white. When a coral bleaches, NOAA says, it is not dead. If the stress is not severe, corals have been known to recover. If the loss of algae is prolonged and the stress continues, the coral eventually dies. Warm water is the usual cause, but not the only one. In January 2010, cold water in the Florida Keys caused a bleaching event that killed some coral. The damage can be large. NOAA reports that in 2005 the United States lost half of its coral reefs in the Caribbean in one year because of a massive bleaching event.