NSF Award
2326437
Forested watersheds have historically provided pristine sources of water to address approximately 50% of the Nation’s need for drinking water. However, the increased frequency and severity of wildfires in forested watersheds are adversely impacting downstream water quality due to the exports of sediments, nutrients, and dissolved organic matter. Heat from wildfires initiates and catalyzes a series of chemical reactions in soil organic matter that result in the formation of pyrogenic organic matter (PyOM). In a wildfire impacted watershed, PyOM has the potential to impact surface water quality, aquatic biogeochemical processes, and the operation of downstream water treatment plants. The overarching goal of this project is to evaluate the chemical composition, environmental fate and reactivity, and timing of PyOM release from a wildfire impacted watershed. To advance this goal, the Principal Investigators (PIs) propose to carry out an integrated laboratory and field research program to 1) characterize the chemical composition of PyOM using optical spectroscopy and ultra-high resolution mass spectrometry, 2) evaluate the environmental fate of PyOM during photodegradation and biodegradation, and 3) monitor the timing of PyOM export from a wildfire-impacted watershed with in-situ optical sensors. The successful completion of this project will benefit society through the generation of new fundamental knowledge and data to advance the assessment and evaluation of the environmental fate and transport of PyOM in forested watersheds and its potential impact on downstream water quality. Additional benefits to society will be achieved through outreach and education activities including the mentoring of one graduate student at Texas A&M University and one graduate student at Washington State University.<br/><br/>Wildfires can drastically change the quantity and quality of dissolved organic matter (DOM) that is exported from burned watersheds to downstream surface water systems due to the formation of pyrogenic organic matter (PyOM). The presence of PyOM in wildfire-impacted watersheds has the potential to impact aquatic biogeochemical processes and the removal of organic matter during drinking water treatment. The goal of this project is to evaluate the chemical composition, environmental stability, and timing of dissolved PyOM export from wildfire-impacted watersheds. The specific objectives of the research are to: (1) Evaluate the differences in chemical compositions between background DOM and PyOM; (2) Assess the fate of PyOM during biodegradation, photodegradation, and photobiodegradation; and (3) Evaluate the timing of PyOM release from a wildfire-impacted watershed using in situ optical sensors. PyOM generated from water leaching experiments of laboratory-heated soils will be characterized by elemental composition, optical measurements, and ultra-high resolution mass spectrometry. A multi-year field campaign will evaluate the temporal dynamics of PyOM release from a wildfire-impacted watershed using in situ optical sensors. The successful completion of this research has the potential for transformative impact through the generation of new insight and data from both lab and field studies to advance the fundamental understanding of the fate and transport of PyOM in forested watersheds as climate change exacerbates the frequency and severity of wildfires. To implement the educational and training goals of this project, the PIs will leverage existing programs at their respective institutions to integrate the findings from this research into a K-12 teacher training program (Spark! PK-12 Outreach) at Texas A&M University and a field training program (Science at the Site) at Washington State University designed to attract and engage students from underrepresented groups.<br/><br/>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.
