CHANGE OF THE CONTENT OF ORGANIC COMPOUNDS GROUPS AS A RESULT OF THE SPHAGNUM PEAT DECOMPOSITION

Different groups of organic compounds were specified in hexane-chloroform extract of fuscum peat and Sphagnum hollow peat retrieved in Bakcharsky bog that is situated in Tomsk region. Organic components were identified in native peats taken from a depth of 40-60 cm in elevated (pine-shrub-Sphagnum bog) and low (sedge-Sphagnum lawn) mire landscapes, and after their field decomposition in the same ecosystems during 16 months above and below the water table, at depths of 5-10 cm and 25-30 cm. The analysis of peat extractive compounds was carried out by gas chromatography-mass spectrometry. The total content of all extractives was 309 μg/g abs. dry matter in Sphagnum hollow peat and 281 μg/g abs. dry matter in fuscum peat. After the decomposition, the total content of compounds 2-fold increased in aerobic zone and slightly decreased in the anaerobic zone in fuscum peat, and their content in Sphagnum hollow peat were almost 2 times lower at both depths. These changes were accompanied by a relative increase in content of cetane, as well as some n-alkanes with an even number of carbon atoms in the molecule, carboxylic acids, and C26-ketone (in the aerobic zone of fuscum peat deposit), C25- ketone and alkanes of isoprenoid structure (in the Sphagnum hollow peat). Simultaneously it was observed the relative reduction of content of palmitic acid and isoprenoid alkanes (in the anaerobic zone of fuscum-peat), some alkanes with an odd number of carbon atoms in the molecule, C29-ketone (in Sphagnum hollow peat at both depths) and C27-ketone (at a depth of 25-30 cm in hollow). These results indicate various ways of organic mass transforming during decomposition in elevated (pine-shrub-Sphagnum bogs, ryams, ridges) and low (grass-Sphagnum lawns, hollows) mire ecosystems.