EAR-PF: Controls on weathering, solute fluxes, and geologic carbon cycling in glacierized catchments

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Dr. Anna Bergstrom has been awarded an NSF EAR Postdoctoral Fellowship to work at Colorado State University to study chemical weathering and its role in biogeochemical cycles on glacierized watersheds. Depending on geologic properties and other characteristics of the watershed, watersheds have the potential to be major contributors to the geologic carbon cycle though consumption or release of carbon dioxide. However, the role of glacierized watersheds in the global carbon cycle is unknown because hydrology and solute flux from these systems is poorly understood. This research will unify hydrologic theory and geochemistry in a novel way to understand the controls on weathering-derived impacts in glacierized watersheds of costal Alaska, an area currently seeing rapid glacier mass loss with very large ecologic and economic implications. This understanding will then be applied to a global dataset to evaluate the role of glacierized watersheds in the global carbon cycle. A series of teaching modules for high schools and undergraduate classes will be designed to introduce students to these watersheds and concepts. The postdoc will also give public talks and collaborate with citizen science projects.This research brings together two closely related but not fully integrated theories to understand processes driving weathering-derived solute flux and the strength of carbon sink or source from glacierized watersheds. In watershed hydrology, concentration-discharge relationships are used to infer a process understanding of solute generation mechanisms, with little exploration of the solute fate. In geochemical weathering estimates of flux, this knowledge of varying relationships has not been fully integrated into our understanding of solute flux estimates and carbon cycling. Coupling these two approaches is a powerful way to advance our understanding of the role of glacierized watersheds in global biogeochemical cycles, and the dominant controls on chemical weathering rates more generally. This integrated research framework will be developed for the Wolverine Glacier watershed located on the Kenai Peninsula of Southcentral Alaska using continuous water quality monitoring and regular water sampling for solute chemistry. This will then be applied to, and tested with, a global dataset of glacierized watersheds to understand the dominant processes and watershed characteristics determining the magnitude and nature of weathering-derived solute flux. This research will improve our understanding of hydrologic processes within glacierized watersheds and the role of these watersheds in the global carbon cycle and will provide a large publicly available global dataset of solute flux and landscape characteristics from high solute flux watersheds.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.