Leaf waxn-alkanes in leaves, litter, and surface soil in a low diversity, temperate deciduous angiosperm forest, Central Missouri, USA

The leaf waxn-alkanes in modern ecosystems serve as proxies for assessing the ecologic and climatic conditions in soils, sediments and other geologic archives, and potentially as baselines for future ecological changes. In this study, the concentrations and distributions of long-chain (C-25-C-35)n-alkanes in fresh mature leaves, leaf litter fall, and surface soil (0-5 cm) from 0.4 ha, low diversity (oak-hickory-maple), deciduous angiosperm forest are quantified. Owing to degradation and dilution, leaf litter (350 +/- 227 mu g/g dw) and soil (13 +/- 13 mu g/g dw) each contain significantly lower concentrations of long-chainn-alkanes than fresh mature leaves (574 +/- 291 mu g/g dw). The average chain length and odd-even predominance (OEP) of fresh mature leaves increased and decreased, respectively, in leaf litter and soil indicating preferential and progressive degradation of the more abundant C(27)and C(29)homologues relative to less abundant C(31)and C(33)homologues. A poor relationship between OEP and a normalisedn-alkane ratio(s) demonstrates the large potential effects of inter- and inner-species variability and/or varying effects of degradation on leaf waxn-alkanes, and highlights the potential limitations of the endmember modelling in paleo reconstructions.