Coral Reef Bleaching Found In Belize For The First Time
Coral bleaching caused by environmental stresses is threatening the Western Hemisphere's longest and most pristine barrier reef in Belize, as well as other areas of the western Caribbean and Gulf of Mexico, according to scientists at the Commerce Department's National Oceanic and Atmospheric Administration.
The same warm waters that spawned or strengthened hurricanes in the western Atlantic this year also are associated with this occurence of coral bleaching. From August through October, NOAA satellites detected elevated sea surface temperatures spanning much of the Gulf of Mexico and the western Caribbean basin from Belize to Jamaica, Honduras and Venezuela.
Coral reef bleaching occurs when stress, such as high ocean temperatures, cold ocean temperatures, elevated ultraviolet light, sedimentation and toxic chemicals, causes zooxanthellae, a symbiotic algae living within the corals' tissues, to be expelled from coral, leaving it a ghostly white. Corals need this symbiotic relationship with zooxanthellae for nutrition, health, and survival. Although most corals survive infrequent bleaching episodes, repeated or sustained bleaching events kill corals.
Coral bleaching triggered by warm temperatures became a frequent problem in the 1980's to early 1990's. In 1983, increased ocean temperatures related to the El Nino resulted in widespread bleaching, mortality and even extinction of corals in the eastern Pacific and bleaching at many sites in the western Atlantic/Caribbean. Subsequent El Nino events have been connected with bleaching in the Pacific and Atlantic, and may be related to the current bleaching episodes. However, reefs in Belize and many neighboring nations in the western Caribbean/ Gulf of Mexico region had been spared from this disturbance.
NOAA's preliminary climate predictions indicate that after the current (1995-1996) cold period ends, another El Nino, perhaps a strong one, may be on the horizon for 1996-1997.
In addition to remote sensing and climate predictions, NOAA has been a leader with other federal agencies and internationally in the development of the International Coral Reef Initiative.
The Initiative's priorities include support for the establishment of a global coral reef monitoring network, launched by the Intergovernmental Oceanographic Commission, to be able to definitively tie coral reef events such as bleaching to their environmental causes.
Reports of recent widespread bleaching of corals in the western Caribbean were published in the Nov. 10 issue of Science Magazine.