EAR-PF: Biomass burning in the terrestrial Arctic during past warm periods: New insights from organic biomarkers in Lake El'gygytgyn (Siberia)

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Dr. William Daniels has been granted an NSF EAR Postdoctoral Fellowship to carry out research and education plans at the University of Massachusetts Amherst. The research will use geologic records of past wildfires to investigate factors that might impact future fire prevalence in the Arctic tundra. Wildfires play an important role in forest ecology, contribute to the global carbon cycle, and can interfere with human activities. In the Arctic, wildfires are historically rare, but their frequency is increasing as climate warms. This recent trend is surprising given that existing paleofire records demonstrate that a cold and dry climate is more conducive to burning then a warm and wet climate. Ancient lake sediments from the Siberian Arctic will be analyzed for evidence of past wildfires during time periods that span a wide range of climatic conditions to better understand climate-wildfire linkages. The study will test the ideas that permafrost, aridity, and vegetation can influence the relationship between temperature and tundra wildfires. The research will be coupled with community education activities, including teaching environmental science camps for local youth in Massachusetts and Arctic Alaska.The proposed research will use organic geochemical proxies in a Lake El'gygytgyn sediment core covering 3.6 million years to reconstruct variations in Arctic biomass burning over the Plio-Pleistocene. Levoglucosan and polycyclic aromatic hydrocarbons, molecular byproducts of biomass burning, will be compared with independently-derived paleoclimate reconstructions during the mid-Pliocene Warm Period (3.02-3.26 Ma; a key analog for future global climate) and during the Superinterglacial Marine Isotope Stage 31 (1.06-1.08 Ma). Results will provide a direct comparison of glacial-interglacial variability during the Pliocene versus the Pleistocene to test if permafrost and vegetation shifts under prolonged warming could lead to profoundly different fire systematics. The study will further develop and test molecular fire proxies needed to generate additional paleofire records.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.