Effect of the biota diversity on the composition of low-molecular-weight water-soluble organic compounds in southern tundra soils

Abstract

Water extracts from the organic horizons of southern-tundra loamy permafrost-affected soils (a surface-gleyed tundra soil, a surface-gleyed soddy tundra soil (Haplic Stagnosols (Gelic)), and a peaty tundra soil (Histic Cryosol (Reductaquic)) and their undecomposed moss layers have been analyzed. The total weight concentration of the cations (Ca2+, Mg2+, K+, and Na+) determined by the atomic absorption method reaches 20 mg/dm3 in the organic horizons and 40–90 mg/dm3 in the undecomposed moss layers. Potassium and calcium ions dominate in all the organic horizons (80–90% of the total weight); potassium ions prevail in the mosses (about 70%). The weight concentration of carbon in the water-soluble organic compounds is 0.04–0.07 g/dm3 in the organic horizons and 0.20–0.40 g/dm3 in the undecomposed moss layers. The content of low-molecular-weight organic compounds (alcohols, carbohydrates, and acids) identified by gas chromatography and chromatomass spectrometry is 1–30 mg/dm3 in the organic horizons of the soils and 80–180 mg/dm3 in the mosses, which does not exceed 26% of the total organic carbon in the extracts.