Biogenic Elements of Atmospheric Fallout and Impact of Sub-Mediterranean Forest Communities of Downy Oaks on Changes in the Chemical Composition of Atmospheric Precipitation

Abstract

In this work, a study of the biogenic composition of atmospheric precipitation and its change during the passage through the crowns of trees of a downy oak forest was carried out. First of all, the content of rainwater-soluble compounds of all the considered elements in rainwater under the forest canopy was higher than in rainwater in an open area. It was revealed that the main forms of nitrogen in the atmospheric fallout were nitrates and ammonium. The average concentrations of nitrogen anions in rainwater collected under the canopy were higher than in rainwater collected in the open area. The proportion of nitrite nitrogen in rainwater under the canopy was 6% higher than in rainwater collected in the open area. Simultaneously with the increase in the proportion of nitrite nitrogen, nitrate nitrogen decreased. For all considered biogenic substances, an increase in their content was observed in the warm period of the year. We found an inverse relationship between the concentration of inorganic nitrogen and phosphorus in precipitation and the relative air humidity and wind speed. It was established that the pH of precipitation falling under the crowns of trees was lower than the pH of precipitation in the open area. It was revealed that the increase in the concentration of biogenic elements was in accordance with the phase of plant development during the growing season.