23
September 2004
Accentuate the positive
A long-term fertilization experiment in Alaskan arctic tundra has produced results that confound predictions of how nutrient-limited northern ecosystems will respond to climate warming. Previous predictions suggested that warmer soils should increase nutrient availability, stimulating plant production more than decomposition and increasing ecosystem carbon storage. But in this 20-year study, increased nutrient availability caused a net ecosystem loss of 2,000 grams of carbon per square metre. Decomposition was stimulated more than production. Increased nutrient availability, a likely result of warming, may therefore lead to substantial net transfer of carbon from these ecosystems to the atmosphere and a positive feedback to climate warming.
Ecosystem carbon storage in arctic tundra reduced
by long-term nutrient fertilization
MICHELLE C. MACK, EDWARD A. G. SCHUUR, M. SYNDONIA
BRET-HARTE, GAIUS R. SHAVER & F. STUART CHAPIN III
Nature 431, 440–443 (2004); doi:10.1038/nature02887
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Global change: Carbon conundrum on the tundra
WENDY M. LOYA & PAUL GROGAN
Vast amounts of carbon are locked into soils at northern high latitudes.
The vexed question of how these ecosystems will respond to global warming
is addressed by a long-term experiment in the Arctic.
Nature 431, 406–408 (2004); doi:10.1038/431406a
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