IMPORTANT USER ALERT (2 July 2024): This past weekend, a storage server at NOAA's Center for Satellite Applications and Research, which delivers the NOAA Coral Reef Watch data, suffered a hardware failure. The issue is being addressed, and we hope to have the NOAA Coral Reef Watch data back up and running as soon as possible. (1) The most recent data will be made available first; historical data may take time to be restored. (2) If you need specific data that are not yet available, please contact us at (3) If you use code to pull data, please revise your code to use “…/socd/…” in lieu of “…/sod/…” in all relevant web addresses for all future needs. We apologize for any inconvenience this may cause.

Satellites & Bleaching

Coral Bleaching

previous page next page
Intro to Bleaching   |   What Is a Coral Reef?   |   Coral Bleaching   |
   Why Should We Care About Our Coral Reefs?
bleached coral

Close-up view of bleached coral polyps. Click the image for a larger view and more information.

Mass coral bleaching is caused by unusually high water temperatures that stress corals. Coral polyps will expel the symbiotic algae that live in their tissues, exposing the white skeleton underneath. Corals typically recover from mild bleaching, gradually recovering their color by repopulating their algae. However, if the bleaching is severe or prolonged, individual polyps or whole colonies will die. Please read on for more information about coral reefs, and the causes and consequences of coral bleaching.

previous page next page


NOS Web site footer