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5 December 2013 11:26 am ,
Vol. 342 ,
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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3 October 2001 7:00 pm
Intense cyclones pummel Australia's northeastern coast 10 times more often than previously believed, according to a new analysis of piles of destroyed coral. As a result, reefs, tropical forests, and even towns in Queensland may face devastation from storms every 200 to 300 years. The finding, published in the 3 October issue of Nature, echoes earlier studies of the history of hurricanes in the southeastern U.S.
Because written records usually go back just a century or two, researchers must use detective work to discover how often storms strike. Fortunately, the strongest hurricanes--called cyclones in the southern hemisphere--leave telltale remains. The signs include layers of sand driven far inland and massive ridges of debris near the beach, such as shattered chunks of coral reefs. The latter are especially visible along the shore of the Great Barrier Reef, which graces 2000 kilometers of the Queensland coast.
To decipher Queensland's cyclone history, coastal geologists Jonathan Nott of James Cook University in Cairns and Matthew Hayne of the Australian Geological Survey in Canberra measured parallel ridges of broken coral at seven of the reef's islands and bays. Most deposits were a few meters high, and radiocarbon dating showed that they ranged in age from a few dozen years old to more than 5 millennia. Nott and Hayne then devised a model to estimate the intensity of each cyclone. The severest storms, they reasoned, broke off the most chunks of coral and created the biggest surges of water, thus building the highest ridges. They found that "category 5" cyclones, the most destructive storms, ravaged some part of the reef every 2 to 3 centuries, on average. Previous estimates were once every several thousand years. "This is something no one predicted or expected," Nott says. Urban planners, emergency response coordinators, and insurers are "very concerned" by the finding, he notes, because their plans and rates are based on a far lower perceived risk of catastrophic storm damage.
Category 4 and 5 hurricanes appear to bombard the Atlantic and Gulf of Mexico coasts in the U.S. with the same frequency, says biogeographer Kam-biu Liu of Louisiana State University in Baton Rouge. "I welcome the addition of a new indicator for reconstructing storm histories," says Liu, who bases his own research on sand buried in coastal lagoons. But Nott's beach-ridge approach, he says, might be harder to apply elsewhere in the tropics, because it may depend on Australia's unique coastal geology.