CAREER: The Legacy of Wildfire on Carbon Watershed Biogeochemistry

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Wildfires occur more regularly and with greater severity throughout the western United States. In addition to threatening our safety, these fires also change ecosystems. Severe fires release large amounts of carbon into the atmosphere, contributing to climate change. Wildfires also change the way carbon and water move and are stored within ecosystems. This project aims to understand how severe fire alters the movement and fate of carbon from land to water over multiple timescales and forest types. Field observations, laboratory experiments, and computer models will quantify the size and fate of terrestrial and aquatic carbon pools. Results will improve our ability to understand the feedbacks between a changing climate, increasing wildfires, and forest carbon cycling. In addition, this project will create a partnership between Colorado College, a small liberal arts school, and two large research focused universities: University of Utah and Texas A&M University. This partnership will provide increased opportunities for undergraduates, providing research experiences both within and outside the classroom. The project will train more than 75 undergraduate students and two postdoctoral scholars. Results from this project will be shared with the Colorado Springs community through an outreach-oriented exhibit at the Fine Arts Center at Colorado College via a partnership with an artist. Severe fire results in large shifts in terrestrial ecosystem carbon (C) stocks and alters watershed hydrology, shifting flow paths and thus the sources and processing of organic matter to aquatic ecosystems. Currently, terrestrial ecosystem C models do not adequately incorporate inland waterways, resulting in a significant overestimate of net ecosystem production, i.e. the size of the terrestrial C sink. The overarching goal of this research is to better understand how disturbance alters C processing along flow paths within the terrestrial environment and the fate of C within aquatic ecosystems. The project will leverage field campaigns, seasonal and year-round precipitation and stream water collection, controlled laboratory experiments, and modeling efforts at four sites across Colorado that form a “natural experiment”. Project study sites include two subalpine sites and two montane sites, each consisting of one landscape with tree reestablishment and one with few to no established seedlings or saplings, almost 20 years post fire. C stocks and processes will be quantified and characterized across these gradients to better identify causal relationships that will help predict how ecosystems will respond to ongoing and future disturbance. Further, project results will have important implications for incorporating disturbance and aquatic systems into ecosystem C models, with the potential to inform paleoecological reconstructions of fire’s impact on ecological processes.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.