Molecular organic geochemical peculiarities of lacustrine core sediments in Fildes Peninsula, King George Island, Antarctica

Abstract

The peculiarities of lipids in lacustrine core sediments from Fildes Peninsula, King George Island, Antarctica, are reported. The origin of high-molecular-weight n-alkanes, alkenes, fatty acids, alcohols Is supposed to be related to the abundant moss occurring in the sediments. Abundantiso- andanteiso-fatty acids that occur in the sediments indicate a relatively strong bacterial activity in non-ice-cover zone than in other regions in Antarctica. The C18:2 unsaturated fatty acids mainly originate from autochthonous algae in the sediment pool, and the C18:2C18:0 ratios in the profile are controlled more by paleotemperatures than source assemblies. Long-chain alkenones were identified in freshwater lacustrine sediment in Antarctica for the first time, of whichPrymnesiophyceae is assumed to be the source organism. High relative abundance of C37:4 homologue in long-chain alkenone well correlates to the severely cold climate in Antarctica.