ABSENCE OF CARBON-ISOTOPE FRACTIONATION OF INDIVIDUAL N-ALKANES IN A 23-YEAR FIELD DECOMPOSITION EXPERIMENT WITH CALLUNA-VULGARIS

Distributions and carbon isotope compositions of individual n-alkanes have been monitored during a 23-year decomposition experiment using li tter-bags of Calluna vulgaris shoots buried in a peat bog in the Moor House Nature Reserve. After 23 years, up to 90% of weight loss had occ urred for both bulk litter and for the C-23-C-35 n-alkane fractions. H owever, such extensive degradation was not accompanied by molecular ca rbon isotope fractionation - the delta(13)C values of individual n-alk anes remained virtually unchanged. Biomarker n-alkane delta(13)C value s are thereby further validated as proxies for palaeoenvironmental rec onstruction and as tracers of carbon flow in soils and sediments. (C) 1997 Elsevier Science Ltd.