13 July 2007The AustrianPadraic Murphy
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 when temperatures increased.
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.
The new research suggests coral is suited to climate change and 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.
Before the research was released this week, many scientists believed only a few coral species harboured the algae, but it has now been shown to be much more widespread. The research shows coral has the ability to "shuffle" the algae, maximising life-sustaining 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 the study's lead researcher, Madeleine van Oppen.
She acknowledged the work was viewed as controversial in coral reef sciences.
The research team believes bleaching, widely associated with the death of coral, is part of coral's natural cycle of life.
The presence of the heat-resistant algae had been missed by other researchers, Dr van Oppen said, because their techniques could not detect it at low abundance.
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," Dr van Oppen said.
