Isoprenoid emissions by the Mediterranean vegetation in Castelporziano

Abstract

Isoprenoids (isoprene, monoterpenes, and sesquiterpenes), represent an important category of volatile organic compounds (VOC) naturally emitted into the atmosphere by a multitude of plant species in response to light and temperature. Mediterranean regions are active photochemical reactors due to the high temperatures and solar radiation. Under these conditions, fast reactions triggered by isoprenoids in the low troposphere lead to ozone and aerosol production. On the other side, isoprenoids have been shown to protect plants from oxidative stress. The Presidential Estate of Castelporziano has been a key Mediterranean test site to investigate isoprenoid emissions from a large variety of Mediterranean forest ecosystems. Field studies in Castelporziano in the last two decades highlighted a predominant role of the vegetation as monoterpene emitter while isoprene, the major VOC emitted by plants on a global basis, is emitted in much lower amount. This finding must be taken into account when parameterizing biogenic emission models to predict dynamics of atmospheric chemistry at regional and global scale.