THE BIOGEOCHEMISTRY OF ELLESMERE LAKE, UK .1. SOURCE CORRELATION OF LEAF WAX INPUTS TO THE SEDIMENTARY LIPID RECORD

Analyses of the free lipid distributions from Ellesmere Lake sediments taken from two depths, and comparisons 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 C20-C50 were seen. C28 and C29 sterols were observed in both sediment and leaf waxes, but C27 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. C20-C30 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.