Latest forecast shows coral on a knife-edge as
waters heat up
Researchers at the Australian Institute of Marine Science (AIMS)
have identified early warning signs that could predict a coral
bleaching event several months ahead of a deadly heat wave.
A world authority on coral bleaching, Dr Ray Berkelmans of AIMS
said patterns have emerged over 12 years of tracking sea temperatures.
Until now Researchers and managers have so far only been able to
"nowcast" bleaching conditions using tools such as automatic weather
stations and satellite "Hotspot" maps.
"In our search for indicators to help us "forecast" bleaching
events, we’ve found that persistent westerly wind bursts off PNG
leading into summer and unusually intense cold water upwelling at the
edge of the continental shelf signal a change in tropical ocean
currents and weather patterns which are then usually followed by
bleaching." These unusually large upwelling events seem be associated
with persistent westerly wind bursts off PNG leading into summer."
Dr Berkelmans coordinates the Sea Temperature Monitoring Program,
which covers 50 different sites at multiple depths on and adjacent to
the Great Barrier Reef (GBR). The program was initiated in 1992 and
has become the largest and most comprehensive regional sea temperature
monitoring program in the world, clocking over 10-million data points.
Currently conditions in the Coral Sea and the western Pacific are
teetering on a knife-edge with temperatures and current patterns
dangerously close to those that have preceded bleaching in the past.
"The Equatorial temperatures are unusually warm for this time of
year. We’re also seeing those westerly wind bursts and a slowing down
of the south equatorial current over the past few months. If these
conditions continue through December we’ll be very concerned, "," he
said. "We haven’t seen any unusual upwelling activity yet, but we are
watching closely for this over the next few weeks."
Sea temperature is the most important environmental parameter
governing the distribution, abundance and physiological function of
marine life. Using data from the monitoring program scientists have
been able to establish heat tolerance thresholds of coral in different
regions of the GBR.
The information has also enabled scientists to tackle a wide range
of other problems, including risk assessments for ballast water and
invasive pests at Queensland ports, sea grass expansion and dieback,
and numerous other marine ecological studies.
The Program operates on a shoestring with the help of tourist
operators, other researchers, volunteer dive groups, and consultants
who exchange the temperature loggers every 6-12 months. "Without their
support this program would not exist," said Steve Neale, the man
charged with the day-to-day operations of the program over the last 6
years.
With the expertise of AIMS spatial analyst Stuart Kininmonth the
monitoring data has been made available ‘live’ via a new
web site on the World Wide Web.
"The logger data at this site are linked with data from automatic
weather stations to help reef managers and users monitor the current
conditions that can indicate state of coral stress and ensure human
induced pressures on vulnerable reefs are kept to a minimum," said Mr
Kininmonth.
The Sea Temperature Monitoring Program is co-funded funded by the
CRC Reef, Great Barrier Reef Marine Park Authority and the Queensland
Ports Corporation.
