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Carbon dioxide exchange in a high‐arctic fen estimated by eddy covariance measurements and modelling
Author(s) -
Soegaard Henrik,
Nordstroem Claus
Publication year - 1999
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1365-2486.1999.00250.x
Subject(s) - eddy covariance , carbon dioxide , environmental science , arctic , covariance , atmospheric sciences , climatology , oceanography , ecosystem , geology , statistics , chemistry , ecology , mathematics , biology , organic chemistry
Summary The high‐arctic environment is an environment where the consequences of global warming may be significant. In this paper we report on findings on carbon dioxide and water vapour fluxes above a sedge‐dominated fen at Zackenberg (74°28′N, 20°34′ W) in The National Park of North and East Greenland. Eddy covariance measurements were initiated at the start of the growing season and terminated shortly before its end lasting 45 days. The net CO 2 flux during daytime reaches a high of 10 μmol m –2 s –1 , and around the summer solstice, net CO 2 assimilation occurred at midnight, resulting in net carbon gain during the night. The measured carbon dioxide fluxes compare well to estimates based on the photosynthesis model byCollatz et al . (1991). The total growing‐season net ecosystem CO 2 exchange was estimated to be 96 g C m –2 based on the carbon dioxide model and micrometeorological data. Finally, the combined CO 2 assimilation and soil respiration models are used for examining the dependence of the carbon dioxide budget on temperature. The ecosystem is found to function optimally given the present temperature conditions whereas either an increase or a decrease in temperature would reduce the ecosystem CO 2 accumulation. An increase in temperature by 5 °C would turn the ecosystem into a carbon dioxide source.