Australian weather local cause of coral reef bleaching

31 October 2017
Study instrumentation to understand the controls on the thermal environment of coral reefs, deployed at Heron Reef, Great Barrier Reef, Australia.  Image credit:  Melissa Saunders.

Local weather patterns cause more extensive coral bleaching on Australia’s Great Barrier Reef than the El Niño effect, a new University of Queensland study has found.

UQ Atmospheric Observations Research Group members Professor Hamish McGowan and Dr Alison Theobald said  that the study examined changes in weather patterns during El Niño events and concluded that local meteorology has been the primary cause of coral bleaching on the Great Barrier Reef during El Niño events over at least the past 34 years.

“Historically, it was believed that  El Niño-driven change in sea surface temperatures caused the most devastating mass coral bleaching on the Great Barrier Reef,” said Professor McGowan of UQ’s School of Earth and Environmental Sciences.

“However we found that changes in meteorology which result in light winds, high surface air temperatures and humidity, and clear skies over the Great Barrier Reef are linked to anomalously warm waters over individual coral reefs that experience bleaching.”

Professor McGowan said it was essential to understand the energy balance of individual coral reefs at scales of tens of square kilometres under different climate states such as El Niño and La Niña in a warming climate.

El Niño is the extensive warming of sea surface temperatures in the central and eastern tropical Pacific every three to seven years that leads to a major shift in weather patterns across the Pacific, while its opposite event is known as La Niña.

Professor McGowan said the research could inform predictions of coral bleaching, and help in developing environmental management policy to ensure coral reefs such as on the World Heritage-listed Great Barrier Reef  were protected for future generations.

The study, ENSO Weather and Coral Bleaching on the Great Barrier Reef, Australia, is published in Geophysical Research Letters (doi: 10.1002/2017GL074877).

Media:  Professor Hamish McGowan, h.mcgowan@uq.edu.au, +61 7 336 56651

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