Habitat Influence on the Molecular, Carbon and Hydrogen Isotope Compositions of Leaf Wax n-Alkanes in a Subalpine Basin, Central China

Abstract

Epidermal leaf waxes of terrestrial higher plants have been widely utilized for the reconstructions of paleoenvironment and paleoclimate in peat deposits. In this study, specimens of four plant species growing in both peatland and non-peatland habitats were retrieved to compare their molecular, carbon (δ13C) and hydrogen (δ2H) isotopic compositions of leaf wax n-alkanes from a closed subalpine basin in Central China. Three of the four species show quite higher total concentrations of n-alkanes in the relatively dry non-peatland setting than in the peatland. In addition, the δ2H values of long-chain n-alkanes are generally less depleted in the peatland and are comparable among different plant species, which is interpreted as the influence of inundation condition and the possible limited supply of photosynthetic products. This study reveals different patterns of plant wax molecular and isotopic compositions between peatland and the surrounding non-peatland conditions, and confirms the paleoenvironmental potential of leaf wax ratios on the peat sequences.