When peatlands and permafrost lose moisture, huge amounts of carbon sequestered there can oxidize and return to the atmosphere as carbon dioxide, a greenhouse gas (SN: 12/16/00, p. 396). Now, researchers in Wales, where peat is common, suggest the key that unlocks the carbon is an oxygen-stimulated chemical reaction catalyzed by a single enzyme.
Up to 30 percent of the carbon in the world's soil is locked into the Northern Hemisphere's peatlands, and many peatlands have been stockpiling carbon since the last ice age. In these areas, moss and other vegetation grow atop water-saturated, oxygen-poor, and partially decomposed vegetation layers from previous years, says Chris Freeman, a biogeochemist at the University of Wales in Bangor.
The release of carbon dioxide from peat turns out to be a complicated process. Hydrolase enzymes often help break down vegetation and liberate carbon dioxide. Despite their efficiency in many other oxygen-poor environments, these enzymes don