Investigation of relationships between throughfall and bulk depositions in different stands of Western Blacksea forests

This study was carried out to determine atmospheric precipitation and soil loads in the Western Black Sea Region between 31 October 2019 and 1 November 2020. Bulk and troughfall samples were collected during 23 weeks in Uludağ fir stand of Bolu, 26 weeks in the black pine stand of Araç (Kastamonu), and 27 weeks in the oriental beech stand of Ayancık (Sinop). Collected samples were analyzed for the major cations and anions and their fluxes in throughfall and rainfall events were determined. The pH and the electrical conductivities of the precipitation samples were determined, and monthly and seasonal differences were examined. Throughfall samplers were established as twenty in total and bulk samplers as three rain samplers on the open area closest to the throughfall precipitation collection area. Monthly changes in the ionic compositions were tested by using One-way ANOVA. Significantly higher fluxes were determined for all the base cations in troughfall samples compared to bulk samples. Compared to bulk precipitation, significantly higher fluxes of base cations were found in measured throughfall precipitation samples (except calcium in all stand types and ammonium nitrogen in Larch and eastern beech stands) indicating that significant amounts of cations were deposited by the canopy in all stand types. Both throughfall and bulk precipitation pH levels showed weak acid or neutral characters. It was observed that the average electrical conductivity values of the precipitation waters in all stands during the measurement period were below 250 µS cm-1 belonging to the low saline water class. Sulfate sulfide and chloride precipitation fluxes were the highest in throughfall and bulk samples at all three stations. In cations, calcium and potassium precipitation fluxes were found at high levels in throughfall samples, while calcium and potassium precipitation fluxes were observed at the highest levels in Aladağ, calcium and ammonium nitrogen in Araç, and calcium and sodium precipitation fluxes in Ayancık. KEYWORDS: Bulk Precipitation, Anion, Cation, Troughfall, Electrical Conductivity