Leaf waxes in litter and topsoils along a European transect

Lipid biomarkers are increasingly used to reconstruct past environmental and climate conditions. Leaf-wax-derived long-chain n-alkanes and n-alkanoic acids may have great potential for reconstructing past changes in vegetation, but the factors that affect the leaf wax distribution in fresh plant material, as well as in soils and sediments, are not yet fully understood and need further research. We systematically investigated the influence of vegetation and soil depth on leaf waxes in litter and topsoils along a European transect. The deciduous forest sites are often dominated by the n-C-27 alkane and n-C-28 alkanoic acid. Conifers produce few n-alkanes but show high abundances of the C-24 n-alkanoic acid. Grasslands are characterized by relatively high amounts of C-31 and C-33 n-alkanes and C-32 and C-34 n-alkanoic acids. Chain length ratios thus may allow for distinguishing between different vegetation types, but caution must be exercised given the large species-specific variability in chain length patterns. An updated endmember model with the new n-alkane ratio (n-C-31 + n-C-33)/(n-C-27 + n-C-31 + n-C-33) is provided to illustrate, and tentatively account for, degradation effects on n-alkanes.