Exchange of Short Chained Organic Acids between the Biosphere and the Atmosphere

We have investigated the exchange of short chain organic acids between the biosphere and the atmosphere. Emission from different tree species under laboratory as well as field conditions was studied in order to get an estimate of the contribution of the release of organic acids into the atmosphere by the vegetation. Additionally we gathered information about the correlation of the emission with several plant physiological parameters such as photosynthesis, respiration, transpiration and stomatal conductance. Furthermore, a one year study (1994) supported by micrometeorological measurements over an agricultural site will give some insight into the fluctuations of acids in the air as well as the emission/deposition processes. Investigations on the role of leaf litter were done to discuss the role of litter layers in forests, and first experiments on the determination of the apoplastic concentration of acids and ions will help to discuss production, transport and release phenomena within and from plant tissues.