1 Department of Systems Biology, Technical University of Denmark2 Department of Chemical and Biochemical Engineering, Technical University of Denmark3 Ecosystems Programme, Department of Chemical and Biochemical Engineering, Technical University of Denmark4 University of Sheffield5 National Research Council of Italy6 Consiglio per la Ricerca e la sperimentazione in Agricoltura7 University of Antwerp8 Department of Environmental Engineering, Technical University of Denmark
Tropospheric O-3 is a strong oxidant that may affect vegetation and human health. Here we report on the O-3 fluxes from a poplar plantation in Belgium during one year. Surprisingly, the winter and autumn O-3 fluxes were of similar magnitude to ones observed during most of the peak vegetation development. Largest O-3 uptakes were recorded at the beginning of the growing season in correspondence to a minimum stomatal uptake. Wind speed was the most important control and explained 44% of the variability in the nighttime O-3 fluxes, suggesting that turbulent mixing and the mechanical destruction of O-3 played a substantial role in the O-3 fluxes. The stomatal O-3 uptake accounted for a seasonal average of 59% of the total O-3 uptake. Multiple regression and partial correlation analyses showed that net ecosystem exchange was not affected by the stomatal O-3 uptake. (C) 2013 The Authors. Published by Elsevier Ltd. All rights reserved.