[Coral-List] Potential for severe bleaching in Australia and surrounding areas in 2009

Mark Eakin Mark.Eakin at noaa.gov
Tue Jan 6 16:55:50 EST 2009

It's that time of the year again and southern hemisphere waters are  
starting to warm for this year's bleaching season. Unfortunately, the  
bleaching potential for the Great Barrier Reef is high based on  
forecasts and analyses from NOAA and the Australian Government.  The  
area likely to experience the highest temperature anomalies and  
greatest potential for widespread bleaching during the next 12 weeks  
is a region extending southeast from Papua New Guinea to the Solomon  
Islands, the GBR, and New Caledonia.

Greater Barrier Reef:

Some warming has begun in this region, with HotSpots present for most  
reefs of the Great Barrier Reef (GBR) and mild accumulation of thermal  
stress (Degree Heating Weeks of around one degree-week) along the reef  
from Cairns northward.  All of Coral Reef Watch's Virtual Stations for  
the GBR reached their warmest month’s average temperature during  
December 2008.   Recently, local storms cooled the waters along much  
of the GBR, but our seasonal bleaching outlook suggests that it is  
likely that most of the GBR has the potential to experience moderate  
to severe thermal stress by the end of this month.  These conditions  
are expected to continue through February.  Stress levels of the  
magnitude shown by the bleaching outlook model are expected to be  
similar to those that have caused severe bleaching in the past,  
including 2002.  It should be noted that the bleaching potential is  
expected to peak around mid-February when both the bleaching outlook  
model reaches its peak and neap tides are expected along the GBR.   
Weak tidal currents limit the cooling of tidal circulation.  Observers  
already have noted some minor bleaching along the northern GBR.

Coral Triangle:

Ocean temperatures have begun to cool in the Coral Triangle (CT)  
region west of Torres Strait as the sun has moved southward.  HotSpot  
values are diminishing across Indonesia from Borneo to Papua.  HotSpot  
values are now zero in most of that area, so we do not anticipate any  
significant accumulation of thermal stress at this time.  This may  
change with renewed warming around March.

  Thermal stress continues to accumulate just east of Torres Strait  
and in the region between Papua-New Guinea and the Solomon Islands.   
As warming continues and is expected to expand in the Coral Sea,  
thermal stress may continue to accumulate.  Reef locations in the east  
of the Strait, the eastern-most islands of Papua New Guinea (Venema  
and Rossel Islands), and the western side of the southern Solomon  
Islands exceed DHW of 4 (Alert Level 1) and continue to warm.  The  
potential for thermal stress levels that can cause severe bleaching is  
expected to continue through February.

South Pacific:

Some warming with positive HotSpot values and mild accumulation of  
thermal stress has begun along a band from New Caledonia, past Fiji,  
to waters south of Raratonga.  The bleaching outlook model indicates  
that there is a potential for high thermal stress for New Caledonia  
and perhaps Fiji and Tonga, with less extreme warming in the southern  
Cook Islands and French Polynesia.  Warming of waters around New  
Caledonia is expected to continue through February; stress levels of  
the magnitude shown by the bleaching outlook model are similar to  
those that may cause bleaching in New Caledonia.

Indian Ocean:

Some warming with positive HotSpots and mild accumulation of thermal  
stress has begun in the western Indian Ocean around Madagascar.  The  
bleaching outlook model calls for continued low-level thermal stress  
until at least the end of the month.  The bleaching outlook model also  
shows the potential for some warming and threat of mild bleaching  
around Madagascar through January and in western Australia in March.

Our seasonal bleaching outlooks can be found at:


Current HotSpot and Degree Heating Week charts and data formatted for

HDF and Google Earth can be found at:


Time series graphics for index sites can be found at:




You can sign up for automated bleaching alerts at:


Please report bleaching events (or non-events) at:


The official coral bleaching forecast and status from the Great  
Barrier Reef Marine Park Authority can be found at:




C. Mark Eakin, Ph.D.
Coordinator, NOAA Coral Reef Watch
National Oceanic and Atmospheric Administration
Center for Satellite Applications and Research
Satellite Oceanography & Climate Division
e-mail: mark.eakin at noaa.gov
url: coralreefwatch.noaa.gov

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1335 East West Hwy
Silver Spring, MD 20910-3226
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"Now is the time to confront [the climate change] challenge once and  
for all. Delay is no longer an option.
Denial is no longer an acceptable response. The stakes are too high.  
The consequences, too serious."
President-Elect Barack Obama, Nov. 18 2008

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