Arctic tundra: A source or sink for atmospheric carbon dioxide in a changing environment?

Intact cores from the wet coastal arctic tundra at Barrow, Alaska, were used as microcosms in the measurement of CO2 fluxes between peat, vegetation, and atmosphere under controlled conditions. Net ecosystem CO2 uptake was almost twice as high at present summer temperatures (4° C) than at 8°. Lowering the water table from the soil surface to -5 cm also had a pronounced effect in decreasing net ecosystem carbon storage. Warming of the tundra climate could change this ecosystem from a sink for atmospheric CO2 to a source.