Global warming won't boost carbon storage in tundra.The notion that warmer tundra tundra (tŭn`drə), treeless plains of N North America and N Eurasia, lying principally along the Arctic Circle, on the coasts and islands of the Arctic Ocean, and to the north of the coniferous forest belt. ecosystems will capture additional carbon dioxide--a favorite argument among skeptics of global warming--isn't supported by new field data. For more than 20 years, researchers have been adding plant nutrients to patches of tundra near Toolik Lake, Alaska. Since 1981, each square meter Noun 1. square meter - a centare is 1/100th of an are centare, square metre area unit, square measure - a system of units used to measure areas of soil in the research plots received 10 grams of nitrogen and 5 g of phosphorous phos·pho·rous adj. Of, relating to, or containing phosphorus, especially with a valence of 3 or a valence lower than that of a comparable phosphoric compound. per year, says Michelle C. Mack, an ecologist at the University of Florida University of Florida is the third-largest university in the United States, with 50,912 students (as of Fall 2006) and has the eighth-largest budget (nearly $1.9 billion per year). UF is home to 16 colleges and more than 150 research centers and institutes. in Gainesville. Those dosages are roughly equivalent to the additional amounts of these nutrients that decaying organic matter in the soil would release if temperatures in the region were to rise around 5[degrees]C, the temperature increase predicted for the region over the next half-century by some climate models. As expected, the nutrient nutrient /nu·tri·ent/ (noo´tre-int) 1. nourishing; providing nutrition. 2. a food or other substance that provides energy or building material for the survival and growth of a living organism. applications led to denser growth of grasses and shrubs, which in turn, sopped up more carbon dioxide carbon dioxide, chemical compound, CO2, a colorless, odorless, tasteless gas that is about one and one-half times as dense as air under ordinary conditions of temperature and pressure. . Between 1981 and 2001, this aboveground carbon storage increased by 1.5 kilograms per square meter. However, the carbon content of the soil dropped by 3.5 kg/[m.sup.2] over the same period, says Mack. The math indicates that every square meter of tundra could lose 2 kg of stored carbon. The finding, reported by Mack and her colleagues in the Sept. 23 Nature, suggests that temperature increases in arctic regions could spur the release of massive amounts of planet-warming carbon dioxide. More than one-third of the carbon in the world's soils is now stored in those high-latitude areas, she notes.--N.S |
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