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13 Jul 07
Barrier Reef `can adapt to warming'
Yahoo News 13 Jul 07
Coral "shuffle" helps reefs survive warmer world: study
Australia's Great Barrier Reef might be able to survive warming sea temperatures, as a result of global warming, better than first thought because some coral algae are more heat tolerant, Australian scientists said.
Coral geneticists from the Australian Institute of Marine Science have found that many corals store several types of algae, which can improve their capacity to cope with warmer water.
"This work shatters the popular view that only a small percentage of corals have the potential to respond to warmer conditions by shuffling live-in algal partners," said institute marine scientist Madeleine van Oppen.
"Simply, when conditions warm the more heat-tolerant algae provide back-up, become more abundant. Some algal types impart greater resistance to environmental extremes," van Oppen said in a statement received on Friday.
Since the 1980s, reefs around the world have been devastated by coral bleaching, where temperature increases of just 1 degree Celsius can cause coral animals to expel the photosynthetic algae that keep them supplied with nutrients.
Numerous scientific studies have warned that global warming of the ocean was threatening the very existence of reefs, such as the Great Barrier Reef.
The Australian scientists said their study had found that coral has the ability to " shuffle" the algae, maximizing nutrients depending on water temperature. They discovered heat-resistant algae by examining the DNA of different types of coral.
But many marine scientists have argued that "back-up" algae were infrequent because of the small number of corals that were shown to host several types of algae.
"The potential for this hidden back-up type (algae) to step in and provide nutrition to coral during heat stress is far greater than currently thought," said Jos Mieog, a PhD student involved in the coral study.
The Australian scientists said this "shuffle" ability might explain why coral reefs have been able to survive for thousands of years during various climate changes.
"This flexibility discovered in our research is important in understanding the past evolutionary success of these coral species and their future survival capacity in the face of a changing climate," said van Oppen.
news.com.au 13 Jul 07
Barrier Reef `can adapt to warming'
THE Great Barrier Reef may be much better suited to surviving climate change and warmer conditions than previously thought. Researchers in north Queensland have found many corals contain microscopic algae that protect them from temperature fluctuations.
The study by the Australian Institute of Marine Science in Townsville, which clashes with the work of many coral experts who have long claimed the reef is doomed by climate change, used DNA analysis to show many corals stored several types of algae that kicked in to provide nutrients at higher temperatures.
Reefs a 'touchstone' for environmentalists
The future of the reef has become a touchstone for environmentalists, some of whom say the reef could be gone within 20 years.
Last year, Nicholas Stern, the author of Britain's Stern Review into climate change, said the reef would die because of global warming. Greenpeace and the World Wild Fund for Nature claim the reef is threatened by global warming.
The latter has called for a reduction of CO2 emissions specifically to save the reef, which it estimates contributes $5.8 billion to the economy.
"Overfishing, land-based pollution and coral bleaching exacerbated by increased sea temperatures due to global warming are all impacting upon (the reef's) natural wealth," the WWF website says.
Coral may be suited to climate change
The new research suggests coral is suited to climate change and that species have survived temperature changes in the past. Researcher Jos Mieog said that when conditions warmed, the more heat-tolerant algae provided back-up, becoming more abundant.
Some algal types imparted greater resistance to environmental extremes.
The research shows coral has the ability to "shuffle" the algae, maximising nutrients depending on water temperature. The AIMS team discovered the heat-resistant algae by examining the DNA of different types of coral.
"The potential for this hidden back-up algae to provide nutrition to coral during heat stress is far greater than previously thought," said lead researcher Madeleine van Oppen.
New research 'controversial'
She acknowledged the work was viewed as controversial.
The research team believes bleaching, widely associated with the death of coral, is part of coral's natural cycle of life. Dr van Oppen said the research helped to explain how coral had survived over thousands of years.
"This flexibility discovered in our research is important in understanding the past evolutionary success of these coral species and their future survival capacity in the face of changing climate," she said.
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