The Truly Wild Life Around Chernobyl
Many animals are in evolutionary overdrive
At first glance, the glistening marshes of Glebokye Lake in Ukraine appear to be paradise. Wild boars stomp by, roe deer leap through the waist-high grass and myriad herons and swans feed in the shallows. Look on the horizon, though, and the skyline of Pripyat, a ghost city abandoned by 45,000 people, is visible. So is the red-and-white-striped tower of the Chernobyl nuclear power station's infamous Reactor 4, which exploded nine years ago. Paradise? Not even close. Glebokye is one of the most radioactive lakes in the world.
There is no disputing that the worst nuclear disaster in history was a human tragedy. But paradoxically, it is providing scientists with a unique opportunity to study how life adapts to extreme adversity. For more than two years, researchers affiliated with the University of Georgia's Savannah River Ecology Laboratory--armed with respirators, dosimeters and protective clothing--have gone to Ukraine to study Chernobyl's flourishing wildlife. On a recent trip, they allowed a U.S. News reporter unprecedented access to observe their work. "All your life you're told of the dangers of radiation, and here are all these organisms living with it," says team leader Ronald Chesser. "How are they managing to survive?"
One clue is being revealed this week at a meeting of the Society for the Study of Evolution in Montreal. Robert Baker of Texas Tech University in Lubbock, and a member of Chesser's group, is presenting startling evidence that Chernobyl field mice are undergoing an extremely rapid rate of evolution. Indeed, he says the amount of evolutionary change in some animal species since the accident is greater than would normally occur in 10 million years.
Life altering. Investigating how small creatures such as Chernobyl field mice are adapting and evolving is part of an emerging scientific discipline called evolutionary toxicology--the study of how radioactive and chemical pollutants alter the life course of species. "Man is deflecting the path of evolution; 200 years from now, we may be living with organisms that are genetically quite different from today's," says John Bickham of Texas A&M University at College Station.
Few predicted a swift comeback of wildlife around the Chernobyl plant. Flaws in the reactor's design combined with judgment errors by the operators caused an explosion on April 26, 1986, which belched into the atmosphere at least 10 times the amount of radiation released by the atomic bomb dropped on Hiroshima in 1945. More than 5 million acres of prime farmland were contaminated, and more than 160,000 people were forced to abandon their homes. The accident also caused nearly 1,500 acres of the surrounding forest to die almost immediately. (Pine trees have large chromosomes that are particularly sensitive to radiation.) Soviet researchers noted steep declines in wild animals and die-offs of small insects and worms living in the forest litter. Cattails with two and three "heads" became common.
Today, much of the original radioactivity has disappeared. Contaminants with short half-lives, such as radioiodine, have completely decayed and longer-lived ones, such as plutonium, radiocesium and radiostrontium, have settled deep into soils, says Richard Wilson, a physicist at Harvard University and a Chernobyl expert. However, high surface radioactivity remains in patches, and contaminants still circulate within the food chain. Mushrooms and berries set Geiger counters screaming. And boars, deer and mice captured in the zone have taken up radiocesium in their muscles and radiostrontium in their bones.
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