INTERANNUAL VARIATION OF THE CO_2 BALANCE IN A SUBARCTIC FEN

摘要

The CO_2 flux between the atmosphere and a natural wetland ecosystem was determined using the micrometeorological eddy covariance technique. The eddy covariance technique is a powerful tool for assessing the annual CO_2 balances as it offers the means for continuous flux measurements on an ecosystem scale. The annual CO_2 balance in the mesotrophic flark fen Kaamanen ranged from -15 to -192 gCO_2 m~(-2) in 1997-2002. The interannual variation in the balances originates mainly from variations during the growing season, especially from the differences in the phenological phases in spring and autumn. The efflux during the wintertime contributes markedly to the annual CO_2 budget, but the interannual variation of the winter efflux is small.