EAR-PF: Abrupt climate change in the alpine: Glacial and ecological responses to the Younger Dryas climate oscillation in the Teton Range, Wyoming

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Dr. Sarah Crump has been granted an NSF EAR Postdoctoral Fellowship to carry out research and professional development activities at the University of California Santa Cruz and Occidental College. Her project is aimed at assessing environmental changes in the western US during and after the Younger Dryas, an abrupt climate change event that occurred approximately 12,000 years ago. She will analyze sediment cores from an elevational transect of lakes in the Teton Range, Wyoming, to investigate how glaciers and montane ecosystems responded to a long cold interval followed by rapid warming. Key questions in both the earth sciences and biological sciences will be addressed, including: 1) how do alpine glaciers respond to rapid climate oscillations? 2) how quickly can treeline elevation and species' ranges shift in response to warming at rates comparable to the modern? and 3) how do coupled glacial-ecological systems co-evolve under rapid climate change? Dr. Crump will engage broad audiences in this paleo-example of abrupt climate change through popular science articles and accessible public talks. This project will provide research opportunities for undergraduates at UCSC and Occidental, as well as field-based educational experiences for high school groups, with a focus on broadening participation in the earth sciences. The Younger Dryas was an abrupt ~1200-year return to glacial conditions during the latest Pleistocene that was likely caused by a temporary collapse of Atlantic Meridional Overturning Circulation. While this event is widely recognized as an archetypal example of abrupt climate change driven by a mechanism that may come into play in the near future, its impacts on distal terrestrial environments remain sparsely documented. Leveraging high-resolution lacustrine sediment records from a network of lakes spanning a bioclimate gradient in the Teton Range, Dr. Crump will use elemental data from scanning x-ray fluorescence to constrain glacier extent before, during, and after the Younger Dryas. She will then analyze sedimentary ancient DNA in the lake cores to reconstruct plant communities through time, thereby constraining the rate of treeline response to a rapid climate oscillation. This project takes advantage of recent developments in genetic techniques to answer essential earth science questions and advance the growing field of molecular paleoecology. The resulting paleoenvironmental constraints on the spatial scale and magnitude of ocean circulation changes driving abrupt climate change will be relevant to multiple scientific communities spanning the geological and life sciences. This project is supported through programs in the Directorates for Biological Sciences and Geological Sciences.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.