Developing a GDGT-Temperature calibration for lake sediment paleoclimate reconstructions across a gradient of Canadian ecozones.

Glycerol dialkyl glycerol tetraethers are a class of lipid biomarkers that in recent decades have been show to act as paleoclimate indicators in lake sediment. New research and recent methodological advances have shown that the 5’ methyl branched tetraether index (MBT5’­­Me ) correlates well with temperature, however its use as a paleoclimate marker requires the development of calibration estimates for the areas under investigation. Efforts are underway to generate global, regional, and lake-specific temperature calibrations for the MBT5’Me index, however none have been made for Canadian regions, and particularly the Arctic, where climate warming is particularly pronounced and is relatively understudied. This study analyzed two transects in Canada, one using lacustrine surface sediment from lakes on the Western coast of Canada, and the other from the Eastern Coast of Canada through Quebec and along the Hudson Bay to create two separate temperature calibrations for use in Canadian ecozones. Preliminary modelling of the Western transect demonstrates that the MBT5’Me index is inversely correlated with latitude, showing promising results for its use as a paleoclimate indicator in lake sediments from these regions.