Chemical and Biochemical Characteristics of Alpine Soils in the Tatra Mountains and their Correlation with Lake Water Quality

Abstract

Soils and lakes were sampled in fifteen catchments in the alpinezone of the Tatra Mountains (Slovak-Polish border) to evaluate the dependence of lake water chemistry on soil properties. The amount of soil in alpine meadows varied from 38 to 255 kg m-2 (dry weight soil <2 mm; average of 121 kg m-2). The average cation exchange capacity (CEC) was 12 eq m-2, average base saturation was 12%, and average $${\text{pH}}_{{\text{CaCl}}_{\text{2}} } $$ was 4.0. Moraine areas had, on average, 13 kg m-2 of <2 mm soil in small deposits between stones. Their chemical properties were similar to mineral horizons of alpine soils but had higher concentrations of P forms. Soil composition was spatially uniform, having coefficientsof variation of all parameters between 5 and 115%, and did not exhibit significant differences between the catchments or along the elevation gradient. Variation in pools of soil constituents was ∼2-fold higher. Soil organic matter concentration was theparameter that most strongly and positively correlated with N, P, S, CEC, exchangeable base cations, exchangeable acidity, and all biochemical parameters (C, N, and P in microbial biomass and C and N mineralisation rates). Lake water concentrations of organic C, N, and total P were positively correlated (P < 0.01) with the pool of soil organic matter in the catchments, while NO3 - concentrations were negatively correlated (P < 0.001). No correlations were found between C, N, and P concentrations in lakes and soil chemistry, indicating the dominant role of soil quantity over quality for surface water composition in the Tatra lakes. Relatively high concentrations of Ca2+, Na+, SO4 2-, reactive Si, and acid neutralising capacity in some lakes were not explained by soil characteristics, and were more probably related to bedrock composition and structure.