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Climate change appears to be awakening a toxic Rip van Winkle in North America's northern peatlands. A new study concludes that more frequent fires promoted by the warming atmosphere are releasing mercury sequestered in the soils at levels up to 15 times greater than previous estimates.
Peatlands are boreal forest ecosystems rich in thick organic soil layers. Because of their chemical makeup, they are efficient at binding and storing mercury. That helps keep the chemical from accumulating in animals such as fish, where high levels can cause nervous system damage in humans who eat them.
Forest fires threaten peat's ability to protect. Between 1960s and the 1990s, the annual area burned in western Canada and Alaska doubled, a result consistent with global climate change, which researchers believe causes more frequent droughts. Previous studies have shown that forest fires release nearly all the mercury stored in ground litter and soils and inject it into the atmosphere.
