[ASC-media] FW: Media release: reef health check finds problems inshore
julian.cribb at work.netspeed.com.au
julian.cribb at work.netspeed.com.au
Mon Aug 7 01:37:58 CEST 2006
Australian Research Council Centre of Excellence for Coral Reef Studies
August 7, 2006 - For Immediate Release
SCIENTISTS CHECK THE HEALTH OF THE REEF
In a major checkup of the health of the central Great Barrier Reef,
scientists report that while corals on the outer reef are in excellent
condition, coral health is in sharp decline close to the Queensland coast.
Inshore corals have been seriously affected by losing the competition for
space with seaweed. The increased competitiveness of seaweeds has been
triggered by increased nutrients and sediment moving off the land (over many
years) and now by coral bleaching caused by the hot summer, reports
Professor Ove Hoegh-Guldberg of the ARC Centre of Excellence for Coral Reef
A 9-day underwater survey by 14 researchers earlier this year covered a
150-kilometre transect of reef running due east from Mackay. They found the
effects of poor water quality and coral bleaching were plainly evident on
"Our results indicate that stresses to reef health occur along a gradient,"
says Guy Marion, a PhD researcher working on the project. "[Inshore] we
observed low coral and fish abundance, and consistent bleaching across all
reefs, however further offshore we observed intact, healthy reef structure
and virtually no bleaching from the stress we saw earlier this year," he
Guy Marion is also working on a novel method for assessing the condition of
the reef over the past 200 years.
His research involves drilling cores from long-lived corals using underwater
air tools, which are then analysed for trace metal elements and nitrogen
isotopic "signatures" within the skeleton.
The cores, which can be up to 2.5m long, can take over an hour of patient
drilling underwater to collect. They are then transported to the lab and
sliced into thin sections where analysis of the organic matter - just 0.01%
of the skeleton- begins.
Sections of the core showing an abnormal jump in the nitrogen "signature"
can pinpoint past flood events and changes in nutrient sources in the water
- a possible sign of man-made pollution.
Each section of the core can be dated, giving a timeline of water quality
for the region, in some cases extending back to the 1880s - prior to
European settlement. These changes in the GBR lagoon health can then be
matched to records on coastal development, temperature, rainfall and floods,
in order to identify the sources of pollution.
"The project is trying to put numbers on the steady, long-term change in GBR
water quality, in order to gauge current conditions relative to baseline,
pre-European water quality. We want to know how inshore reef health has
changed in response to coastal land clearing for city building and farming,"
Marion's work will be combined with the work of his supervisors and
colleagues, who are each using new techniques to provide fresh insights into
the historical relationship between water quality and reef health in the
GBR. "We hope that this approach of integrating multiple land, satellite,
and coral based techniques can become a blueprint study for reef studies
worldwide," says Marion.
The survey is part of a three year project which, on completion, will
provide a detailed diagnosis of aspects of the health of the central Great
Barrier Reef, both past and present, so that policies and practices can be
further developed to ensure that coastal development and reef use is
sustainable in the future.
The survey is part of a collaborative research project between leading
members of the ARC Centre of Excellence and Stanford University in
Guy Marion, CoECRS and The University of Queensland, 07 3365 3548;
g.marion at uq.edu.au
Ove Hoegh-Guldberg, CoECRS and The University of Queensland, 07 3365 1156
oveh at uq.edu.au
Jan King, UQ Communications Manager, 07 3365 1120
Jenny Lappin, CoECRS, 07 4781 4222
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