Washington, October 15 -- NOAA announced today that unprecedented coral bleaching and extremely warm waters occurred throughout the Tropics during the first half of 1998.
Coral reefs -- the "rainforests of the sea"
are some of the oldest and most biologically diverse ecosystems
on earth. Important assets to local and national economies, they
produce fisheries for food, materials for new medicines, and
income from tourism and recreation, as well as protect coastal
communities from storms.
Corals thrive as long as temperatures remain at or below certain temperatures for a given site. An increase of one or two degrees above the usual maximum temperatures can be deadly to these animals. The temperature range for corals to thrive varies from site to site by only a few degrees. While many corals normally recover from short bleaching events, long-term or frequent bleaching may severely weaken the corals leaving them more vulnerable to disease, damage or death.
Data from NOAA's satellites show that during the first half of 1998, more ocean area in the tropics experienced exceptionally high sea surface temperatures, or "hot spots," than observed in any full year since 1982. Approximately 50 countries have reported coral bleaching since 1997. During the El Niño of 1982-83, large areas of coral reef around the world were severely damaged by high water temperatures associated with coral bleaching. The previous annual record for high ocean temperature events was in 1988, which also followed an El Niño event the year before.
Using satellites to measure sea
surface temperatures and identify hot spots, NOAA has been able
to predict coral reef bleaching events in real time over large
ocean areas since 1997, reports NOAA oceanographer Al
Strong. Hot spots are identified when satellite-derived sea
surface temperatures exceed by 1.0 degree Celsius the monthly
average temperature expected during the warm season.
Coral bleaching charts: Florida,
Puerto Rico and Guam
Maps showing twice-weekly distributions
of hot spots are available at:
Movie/animations are posted at:
Maps showing the annual distribution of bleaching from 1969 through 1997 are posted at: http://www.fas.harvard.edu/~goreau
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