Colloquium: Jessica Tierney

"From molecules to climate models: Fossil lipid insights into tropical paleoclimate."

Abstract: The tropics are home to the majority of Earth's water vapor - an important greenhouse gas - and rapid climate reorganization within the tropics affects climate worldwide. Understanding how tropical climate has behaved throughout Earth History is critical to improve our understanding of - and ability to model - tropical climate dynamics. Here I show how we can use molecular biomarkers - fossil molecules preserved in sediments and in the rock record - to learn about past changes in tropical climate. I will focus in particular on the use of the hydrogen isotopic composition of leaf wax lipids as a proxy for the isotopes of precipitation, and will show how we can integrate proxy-inferred isotopic changes with isotope-enabled modeling experiments to illuminate past changes in precipitation amount and atmospheric processes. I will also discuss application of the TEX86 paleothermometer - a proxy based on the relative cyclization of archaeal glycerol dialkyl glycerol tetraether membrane lipids -  towards reconstructing temperature change in lacustrine environments.

Jessica Tierney, NOAA/UCAR Postdoctoral Fellow
Department of Biology and Paleoenvironment, Lamont-Doherty Earth Observatory, Columbia University