Coral bleaching: what is it and why should we care?
Like the rest of the world, much of the Western Indian Ocean is currently experiencing coral bleaching. Coral bleaching reports have already been received in Seychelles, including Cousin Island Special Reserve. On April 15, the United States’ National Oceanic and Atmospheric Administration (NOAA) confirmed that we are in the midst of the fourth global coral bleaching event. Mass events are declared when extensive bleaching occurs at a regional or global level. In this two-part series, Charlotte Dale, a member of Nature Seychelles’ Reef Rescuers explains what coral bleaching is, its impacts, and what scientists are doing in response to the current event.
What is coral bleaching and why is it a concern?
Coral bleaching occurs when these aquatic animals expel their photosynthetic and symbiotic algae known as zooxanthellae that provide them with nutrients and pigments. Without these algae, they become white or pale. Corals expel the algae when they become stressed as result of increased sea temperatures, pollution, or other environmental factors. Coral reefs are especially vulnerable to predicted climate change because they bleach rapidly in response to increased sea surface temperatures. These mass coral bleaching events we have experienced recently are primarily triggered by abnormal increases in water temperature, often associated with intense El Niño activity.
Image: The fourth global coral bleaching event has been declared (Photo: Seychelles Coral Bleaching - Hugo Bret)