Washington, March 5, 1999 NOAA scientists
are working with two Australian groups to improve coral reef
monitoring and help promote
early warnings of future bleaching events. The scientists are
making extensive use of satellites and computerized expert systems.
The reefs are extremely important
and fragile ecosystems. They 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.
Current NOAA satellite and expert
system observations indicate that temperature conditions around
the Great Barrier Reef have been close to the bleaching threshold
temperatures since mid-January. But, scientists from the Australian
Institute of Marine Sciences (AIMS), the Great Barrier Reef Marine
Park Authority (GBRMPA), and reef users have not reported any
major bleaching so far.
Al Strong of NOAA's National
Environmental Satellite, Data, and Information Service uses
satellites to measure sea surface temperatures and identify HotSpots,
warmer- than-usual areas in the oceans where bleaching could
take place. Strong has been able to predict coral reef bleaching
events over large ocean areas since 1997.
Part of the collaboration with the Australians aims to see how
precisely satellites can predict the location of bleaching. Terry
Done, AIMS senior principal research scientist, said, "The
strength of the NOAA HotSpots is in locating the broad general
areas where one might look for bleaching. Our teams are seeing
great patchiness in bleaching within these broad areas, so with
NOAA, we are going to see how far we can push the satellite technology
to explain what we actually see on the reefs."
Jim Hendee of NOAA's Atlantic
Oceanographic and Meteorological Laboratory in Miami, Fla.,
has developed a suite of computerized "expert systems"
scan weather data from U.S. and Australian weather stations.
One system provides an alert via e-mail or the World Wide Web
when conditions are thought to be conducive to coral bleaching.
"Coral reefs -- the rainforests
of the sea -- are some of the oldest and most biologically diverse
ecosystems on earth," NOAA Administrator D.
James Baker said. Baker will address attendees at the second
Coral Reef Task Force meeting on Maui, Hawaii, later this week.
"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."
bleaching can be a sign that the coral is being stressed
by a number of factors, including pollution, sedimentation, high
light levels, reduced water levels, or changes in salinity. Increases
in water temperature of one degree or more for one month above
the summer maximum often result in extensive coral bleaching,
making coral reefs under these HotSpots prime candidates for
About 50 countries have reported
coral bleaching to some degree in their reefs since 1997, Strong
reports. He is among several authors who are publishing these
unprecedented results, primarily over the Eastern Hemisphere
coral reefs, in an upcoming issue of the scientific journal Ambio.
During the El Niño of 1982-83, large areas of coral reefs
around the world, including the Great Barrier Reef, were severely
damaged by high water temperatures associated with coral bleaching.
Bleaching and other problems
facing coral reefs were discussed at the first meeting of the
Coral Reef Task Force in Key Biscayne, Fla., last October. The
Coral Reef Task Force was created by an executive order signed
June 11, 1998, by President Clinton.
Editor's Note: Maps showing twice-weekly distributions of HotSpots
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
For information on NOAA's Coral
Health and Monitoring Program, go to:
For more information on NOAA's Coral Reef Initiative, please