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Global warming-fueled storms could devastate coral reefs

Global-warming weakened reefs could suffer more storm damage

Global-warming weakened reefs could suffer more storm damage
mongabay.com
November 23, 2006

Australia’s Great Barrier Reef and other coral ecosystems could suffer from increasingly powerful storms brought about by global warming according to computer models published by a team of Australian scientists in the journal Nature.

Researchers from the ARC Center of Excellence for Coral Reef Studies (CoECRS) at James Cook University produced the first engineering model to predict how much damage a reef is likely to suffer from violent wave action.

“Coral reef experts have long had a general sense of which coral shapes are more vulnerable during storms than others,” said lead author, Dr. Joshua Madin, who now works at the National Center for Ecological Analysis and Synthesis (NCEAS) in California. “However, to really predict how these events impact the dynamics of coral reefs we needed a way to quantify these vulnerabilities. “Our study offers a solution to this longstanding problem by factoring in the shape of different coral colonies, the strength of the sea-bed to which they attach and the change in force of the waves as they move across the reef. This enables us to predict the likely changes in composition of the coral in response to present and future storms or tsunamis.”



According to the scientists, their research “introduces a new concept — colony shape factor (CSF) — to translate the myriad shapes and sizes of coral colonies onto a simple scale that measures their vulnerability to dislodgment. Any severe event, like a cyclone, imposes a threshold that can be scored on the same scale, allowing scientists to determine which corals will live and which will die.”


Great Barrier Reef in Australia

The researchers say that reefs in the future will become more vulnerable due not so much to stronger storms but to changes in their structure caused by growing levels of carbon dioxide in the atmosphere, which are expected to simultaneously increase sea temperatures, putting reefs at risk of “bleaching”, and ocean acidity, affecting their ability to build their calcium carbonate support structure. These changes will likely reduce the stability of reefs and their capacity to withstand storms.



Reef conservation tool

The researchers say their new model will can serve as a reef management tool.



“The predictive tool we have developed allows managers to assess the vulnerability of their reefs to extreme wave events,” said Dr. Madin. “The ability to estimate the potential damage on a reef for different disaster scenarios could help managers plan for economic losses as well as promote strategies that help the reef recover.”



“Regardless of whether we think of more severe storms as a looming threat or just the ramping up of a natural cycle, one thing is certain,” says Dr Sean Connolly, a CoECRS researcher and professor at James Cook University. “To predict how coral reefs will look under different future scenarios, and to plan accordingly, we needed to know exactly how wave forces impact who lives and who dies on the reef. These new models provide us with that essential tool.”




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This article is based on a news release from the ARC Centre of Excellence for Coral Reef Studies.