CLIMEX project: Response of runoff chemistry after 2 years of elevated CO2 and temperature

Abstract

CLIMEX is an integrated, whole-ecosystem research project studying the response of entire forested catchments to increased CO2 and temperature. KIM catchment receives clean rain, elevated CO2 and elevated air temperature. EGIL catchment receives ambient acid rain and soil warming. During the first 2 years of treatment (April 1994 - April 1996) runoff from both catchments had increased concentrations of nitrate and ammonium relative to undtreated reference catchments and to pre-treatment period. Increased loss of nitrogen from the systems may be due to increased decomposition of soil organic matter induced by the higher temperatures. This increase might lead to acidification in acid-sensitive freshwaters.