Quantifying the relationship between erosion and permafrost thaw in a changing Arctic environment

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Arctic environments are undergoing rapid change. The thawing of permafrost soils, for example, can release vast amounts of carbon to the atmosphere and cause widespread soil erosion. Erosion that exposes deep permafrost soil can in turn redistribute sediment and water across terrestrial and riverine systems. The investigators will take an integrative approach, analyzing paleoclimate fluctuations and watershed topography across space and time, to understand the relationship among climate, permafrost thaw, and soil erosion. Results will improve our ability to predict Arctic system change. Educational outreach to K-12 schools will involve designing hands-on experiments for a truck-based mobile science laboratory that visits schools in and around Pittsburgh, including those serving minorities and under-represented populations. Graduate and undergraduate students supported as part of this study will participate in both research and outreach activities, training a new generation of scientists. The influence of permafrost thaw on soil erosion is largely unquantified to date, as is the dependence of permafrost thaw and soil erosion on topographic attributes, latitudinal location, and climate. This study seeks to: (1) quantify the relationship between soil erosion and permafrost thaw in Arctic environments in the context of paleoclimate fluctuations; (2) explore the dependence of these processes on topographic attributes and latitudinal location; and (3) evaluate and improve the capability of landscape evolution models to simulate erosion in Arctic environments. To accomplish these objectives, the investigators will sample and analyze sediment cores from two clusters of lakes at different latitudinal locations in Alaska. They will integrate topographic analysis and geomorphologic modeling with the chemical signature of aged carbon that is sourced in thawed permafrost and preserved in lake sediments. This approach will improve and guide future modeling efforts to predict the response of the Arctic system to a changing environment.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.