The biogeochemistry of Ellesmere Lake, U.K.—I: source correlation of leaf wax inputs to the sedimentary lipid record

Abstract

Analyses of the free lipid distributions from Ellesmere Lake sediments taken from two depths, and comparison with leaf-wax lipid distributions from six deciduous tree species around the lake were made in order to assess lipid sources. Close correlations of aliphatic lipid distributions in the carbon number range C 20C 50 were seen. C 28 and C 29 sterols were observed in both sediment and leaf waxes, but C 27 sterols were only present in the sediments and were thus assigned a nonleaf-wax source. Unsaturated steroidal ketones were observed both in the sediment and in certain leaf waxes and were assigned specific sources. Alkan-2-ones were not present in the leaf waxes, but were present in the sediment samples, with an almost identical distribution to the sediment n-alkanes indicating a microbially mediated source. C 20C 30 n-aldehydes which have not previously been widely reported in free lipid distributions of freshwater lacustrine sediments, were prominent in the surface sediment and in the leaf-waxes examined.