A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...

Carbon balance and seasonal patterns via eddy covariance measurements in an old-growthAmazon foreestScott R. Saleska 1 , J. William Munger 1 , Daniel M. Matross 1 , Bruce C. Daube 1 ,V.W.J.H. Kirchhoff 2 , Plinio B. de Camargo 3 , Steven C. Wofsy 11 Harvard University, Earth and Planetary Sciences20 Oxford St.Cambridge, MA 02138 USAsrs@io.harvard.edu2 INPE3 CENA/USP, Piracicaba, SPTo assess the role of Amazon forests as a source or a sink for atmospheric CO 2 , we used groundbasedbiometry measurements together with whole-system CO 2 fluxes (via eddy covariance) toexplore the ecological and climatic controls on the carbon balance at an old-growth Amazonforest (Tapajos National Forest, Santarem, Para, Brazil). The initial year (April 2001 – April2002) of eddy covariance measurements suggest that the forest was a modest source to theatmosphere during this period (net ecosystem exchange, NEE = +0.9 Mg C ha -1 yr -1 to theatmosphere, after correcting for “lost flux” during periods of weak mixing when friction velocitywas