[Coral-List] GBR Bleaching Conditions Update - 29 Jan 2004

Paul Marshall p.marshall at gbrmpa.gov.au
Thu Jan 29 18:58:53 EST 2004

The Great Barrier Reef Marine Park Authority Climate Change Program is
dedicated to observing, understanding and reporting coral bleaching events
and other climate change impacts on the Great Barrier Reef. The Climate
Change Program provides regular reports on conditions on the Reef throughout
summer and publishes early warnings of increases in levels of stress or
widespread bleaching of corals. This is the fourth Current Conditions Report
for the summer of 2003/04.

Updated 29 January 2004

On the basis of current conditions and climate predictions for the summer of
2004, the threat of widespread coral bleaching for the Great Barrier Reef
(GBR) region is currently rated as HIGH. Although weather and sea
temperatures have decreased toward seasonal averages at most locations over
recent weeks, conditions are showing signs of warming again and reports of
minor or patchy bleaching have now been received from several locations.

Sea temperatures remain above average at most monitoring sites on the Great
Barrier Reef. Satellite monitoring of sea temperatures by the U.S. National
Oceanic and Atmospheric Administration (NOAA) indicates an alarming increase
in sea surface temperatures in the Coral Sea, reaching levels 1-2 degrees C
above what would be expected for this time of year. Sea surface temperatures
over the Great Barrier Reef region have also increased over the last week,
with anomalies of 0.5 to 1 degree C over much of the GBR region.
Recent conditions on the GBR region over recent weeks suggest that the
recent respite to the warming trend may be short lived. Temperatures remain
close to levels known to cause stress to corals and associated reef
organisms. Critical thresholds that are known to trigger widespread coral
bleaching have not yet been exceeded, however significant coral bleaching
can be expected if the warming trend is resumed over coming months.
Reports received through our BleachWatch program indicate that minor
bleaching of susceptible corals is occurring at locations off Port Douglas,
Cairns, Townsville, Airlie Beach, Orpheus Island and Heron Island. At some
locations, notably off Port Douglas and Cairns, the severity of bleaching
has increased over the last week. The bleaching reports received to date
indicate mostly light or patchy bleaching, although there is an indication
that stress levels are increasing at some sites. These reports do not
necessarily indicate the onset of a mass bleaching event. However more
severe bleaching could develop if sea temperatures continue to rise.

The Great Barrier Reef Marine Park Authority will continue to closely
monitor the situation with the support of BleachWatch participants and in
conjunction with AIMS and NOAA.

The GBRMPA welcomes any reports of coral bleaching. If you regularly visit a
reef site, or if you have seen bleaching on the reef, we would be grateful
for your input to our BleachWatch Program.

For the full current conditions report, for information on how to join
BleachWatch, and for background information on climate change, coral
bleaching and the Great Barrier Reef, visit the GBRMPA web site:

Paul Marshall, PhD
Climate Change Program
Great Barrier Reef Marine Park Authority
Townsville, Australia
phone +61 7 4750 0771
fax +61 7 4772 6093
email p.marshall at gbrmpa.gov.au

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