Press Release

NOAA Satellites Track Extensive Climate-related Coral Bleaching Event on Australia’s Great Barrier Reef

By SpaceRef Editor
February 25, 2002
Filed under , ,

U.S. Reefs Also Face Increasing Threats

Corals are bleaching
over extensive portions of Australia’s
Great Barrier Reef
, a sign that the reef is being seriously
stressed during current record-breaking warm water conditions.
Conditions have worsened since the widespread bleaching reported
several weeks ago, scientists at the Commerce
National Oceanic
and Atmospheric Administration
and their colleagues in Australia
reported today.

NOAA’s Coral Reef Watch Program
provided early warning of the bleaching conditions by using sea
surface temperature data from NOAA’s
polar-orbiting satellites
. Data from the Australian
Institute of Marine Science
, the Great Barrier Reef Marine
Park Authority and the University of Queensland show a vast section
of the Coral Sea and Great Barrier Reef where temperatures are
much higher than normal due to hot, clear summer conditions.

"Reports just in from our
friends at AIMS and GBRMPA tell of a worsening condition,"
said Al Strong, NOAA satellite oceanographer and coordinator
of NOAA’s Coral Reef
Watch Program
. "Our colleagues have compared this bleaching
event to the previous record event during the 1998 El
, noting that the present episode began earlier
in their summer and shows no signs of easing its grip. My colleagues
are casting their eyes seaward for a cyclone to bring cooler
waters to the surface."

"At this stage all the bleaching
observed is still fairly mild, with little visible signs of significant
mortality, but this is certainly just a matter of time if conditions
do not improve dramatically and persistently," said Paul
Marshall of GBRMPA.

AIMS and GBRMPA, having just
concluded a workshop with NOAA on the Great Barrier Reef, are
about to launch a structured survey program that aims to document
extent and severity of bleaching over most of the Great Barrier
Reef. NOAA scientists of the Coral Reef Watch Program have been
assisting GBR scientists with automating several in situ
monitoring sites (towers/buoys) to provide information on reef
conditions as part of a sophisticated coral reef early warning
system that provides real-time alerts via the Internet of possible
coral bleaching events to scientists and managers worldwide.

NOAA satellite data reveal sea
surface temperature anomalies and "HotSpots,"
or areas of the ocean with unusually warm temperatures where
bleaching is likely to occur. Scientists and coral reef managers
world-wide use the NOAA’s Coral Reef Watch information to better
forecast, track and understand coral bleaching events, and participate
in CRW by providing on-the-reef observations. CRW is part of
NOAA’s Coral Reef Program.

NOAA reports that among domestic
reefs, the northwest Hawaiian region around Midway has seen an
increase in sea surface temperatures over the past two decades
of nearly +0.4 deg C/decade much during the past six or seven

Notable sea surface temperature
increases in the Caribbean are larger toward the south but approach
+0.07 deg C/decade near Puerto Rico and the U.S. Virgin Islands
and Bahamas. In the Northern Hemisphere tropics (Equator to 35N
– globally) sea surface temperatures have been inching upwards
at nearly +0.15 deg C/decade (increasing rates toward higher
latitudes). In the Southern Hemisphere tropics (Equator to 35S
– globally), sea surface temperatures have been more slow to
rise, averaging only a third of the Northern Hemisphere increase,
or +0.05 deg C/decade.

Coral reefs are important to our future because they are one
of the earth’s most diverse living ecosystems harboring millions
of animals and plant species that play a key role in the global
food web. They are full of new and undiscovered biomedical resources
and serve as a buffer for coastal communities from storms, wave
damage and erosion.

Coral reefs also attract hundreds
of thousands of divers, snorkelers and other tourists to tropical
coasts every year. This recreation and travel supports a significant
tourism industry dependent on clean water and healthy coral
reefs. Corals live on the upper edge of their temperature tolerance.
Abnormally high water temperatures combined with low winds and
still water can cause destructive bleaching of coral reefs. NOAA
monitors this threat with satellite-derived sea surface temperatures,
ocean surface winds, HotSpots, Degree Heating Weeks (accumulations
of HotSpots) and on-site monitoring stations.

For more information, see:

For coral bleaching indices of the tropical ocean, see:

For HotSpots:

For accumulations of Thermal Stress see:

For information on NOAA’s Coral Reef Program:

GBRMPA Web Site (updates bleaching information regularly)

AIMS Web site:

SpaceRef staff editor.