NOAA Scientists Sound the Alarm on Coral Bleaching

coral bleaching
A partially bleached branching Acropora colony at Coconut Point, American Samoa. Credit: W. Cover, NOAA

NOAA scientists are warning that warm ocean temperatures in the equatorial Pacific and Indian Oceans could set the stage for major coral bleaching events across the globe in 2015.

Their warnings follow severe bleaching in 2014, and come with the release of the most recent outlook from NOAA's Coral Reef Watch, a weekly product that forecasts the potential for coral bleaching up to four months in the future.

Coral bleaching takes place when corals are stressed by changes in conditions such as temperature, light or nutrients. They expel the symbiotic algae living in their tissues, causing them to turn white or pale. Without the algae, the coral loses its major source of food and is more susceptible to disease.

February-May Coral Bleaching Outlook

The outlook shows the greatest threat for coral bleaching through May 2015 is in the western South Pacific and Indian oceans. In the Pacific, thermal stress has already reached levels that cause bleaching in the nations of Nauru, Kiribati, and the Solomon Islands, and is expected to spread to Tuvalu, Samoa, and American Samoa in the next few months. In the Indian Ocean, thermal stress may reach levels that cause bleaching around Madagascar, Mauritius, Seychelles, and parts of Indonesia and western Australia.

coral bleaching
The latest from NOAA Coral Reef Watch's newly-released four-month Bleaching Outlook indicates the greatest threat for coral bleaching through May 2015 is in the western Pacific and Indian Oceans in areas such American Samoa, Samoa, Western Australia, and Indonesia. Credit: NOAA

In another significant advance, NOAA's Coral Reef Watch program has refined its satellite observational capacity that provides near real-time information on coral reef environmental conditions. It now can focus on reef areas as small as five square kilometers, with an increase of as much as 50 times more data than before. This allows coral reef managers and scientists to accurately pinpoint bleaching thermal stress levels at coral reef scales and take actions to protect their coral reefs.

Partners include: NOAA's Climate Program Office, Coral Reef Conservation Program and National Centers for Environmental Prediction funded development of the outlook. NOAA Coral Reef Conservation Program and NASA's Biodiversity and Ecological Forecasting program funded development of the five-kilometer coral bleaching thermal stress products.

See NOAA's press release on this topic here. Visit Coral Reef Watch for more information.

Coral Bleaching in the News

Stay current on the latest news about coral bleaching and how NOAA is working to study and predict it.