Infographic Transcript: The Effect of Increasing Water Temperature on Zooxanthellae and Coral Bleaching
Healthy corals have a symbiotic relationship with microscopic algae called zooxanthellae that live in their tissue. These algae produce the coral's primary food source and give them their color. When ocean water is too warm, corals expel their algae, rendering the coral tissue translucent and making the animal's white skeleton clearly visible. These events are called coral bleaching because its now stark white appearance makes it look as the coral has been “bleached” of color (in addition to having lost its main food source). Corals can survive a bleaching event and recruit new algae, but repeated events cause stress and decrease colony healthy, leading to coral death.
The NOAA Coral Reef Conservation Program was established in 2000 by the Coral Reef Conservation Act. Headquartered in Silver Spring, Maryland, the program is part of NOAA's Office for Coastal Management.