Composition of the lipids of the sphagnum and cotton grass peats in the forest steppe and southern and middle taigas of West Siberia

Resumo

The composition of the organic components of the lipids of sphagnum and cotton grass peats deposited in West Siberia in the limits of different natural climatic zones was studied by chromatography–mass spectrometry. A decrease in the temperature and an increase in the humidity of the environment northwards from the forest steppe to the middle taiga was accompanied by an increase in the concentration of steroids, tocopherols, and pentacyclic triterpenoids in sphagnum peats and by a decrease in the fraction of n-alkanes, n-alkan-2-ones, and carboxylic acids. The relative concentration of carboxylic acids and their methyl esters and also the fraction of n-aldehydes and steroids, in particular, sitosterol, in cotton grass peats were maximal in the zone of a reduced temperature and an excess humidity of air; the relative alkanone content was simultaneously lowered. In general, the peats of the forest-steppe zone were characterized by the decreased concentrations of all of the identified components of lipids other than n-aldehydes and n-alkan-2-ones; the peats of the southern taiga zone were enriched in branched acyclic structures, carboxylic acids and their esters, tocopherols, and cyclic sesqui- and diterpenoids, whereas the peats of the middle taiga zone were enriched in steroids and pentacyclic triterpenoids.