Chemical Denudation in a Geoecosystem in Acid Immision Conditions / Denudacja Chemiczna W Geoekosystemie W Warunkach Kwaśnej Imisji

There is an analysis of the physico-chemical properties and the chemical composition of precipitation in a forest geoecosystem in acid immision conditions. The data used in the analysis was collected between 2000 and 2010. In that period, a drop in the immision scale of S-SO₂ in the atmospheric air had been observed, which consequently was one of the reasons for a drop in the precipitation acidity. The conclusion was that rainwater, after penetrating treetops and trunks, undergoes a significant transformation whose intensity depends on species composition of the forest stand. Statistically relevant differences were found in coniferous stands, in which a substantial drop in pH was noted, in addition to an increase in the load of components accumulated in the soil in relation to atmospheric precipitation. The calculated indicators of the eco-chemical state of waters (Ma%) have revealed that throughfall waters in coniferous stands and fir and beech stemflow contain significant amounts of aluminium, manganese, iron and hydrogen ions in the sum of cations. Also the indicator of acid-neutralizing capacity (ANCaq) shows that these waters are more enriched with sulfate, nitrate and chloride ions than bulk precipitation. The recorded variation eventuates from processes related to dry and humid deposition, as well as ion-exchange processes occurring within the stand. The obtained results point to an intensification of chemical denudation within the trunks, triggering disadvantageous changes in both biotic and abiotic part of the ecosystem. The effects of the increased inflow of souring agents to the soil through stemflow are significant acidification of the top mineral soil horizon and an increase in the hydrolytic acidity.