View article

We determined hydrogen isotope ratios of modern lake-waters and individual lipids from surface sediments of 36 lakes in the eastern North America. The lakes selected lie on two transects (south–north transect from Florida to Ontario and east–west transect from Wisconsin to South Dakota) and encompass large temperature and moisture gradients, and a wide range of lake water δD values (>100‰). The study allows a rigorous test of the applicability of using δD values of sedimentary lipids as paleoclimatic and paleoenvironmental proxies. We examined a range of lipids including C₁₇ n-alkane, straight chain fatty acids, phytol and sterols in both free extracts and ester-bound fractions in the solvent extracted sediments. Useful isotopic indicators are expected to show a linear correlation and constant fractionation factor between their δD values in surface sediments and modern lake water. Our results …