CAREER: From the forest to the stream: Exploring forest land cover controls on dissolved organic matter character and aquatic ecosystem respiration in headwater streams

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Although inland waters comprise only ~1% of Earth’s surface, they play a central role in the global carbon cycle. Large amounts of carbon are delivered to inland waters as terrestrial dissolved organic matter (DOM) in headwater streams. The type and amount of DOM in these streams controls whether that carbon is released to the atmosphere (i.e. stream respiration) or removed from the carbon cycle (i.e. transported downstream and buried). This project will determine the role of forest harvesting, and specifically clear cutting, in controlling carbon cycling and stream respiration in headwater streams. The results from this project will be used to develop predictive models that guide future research and inform management of forested headwater systems. This project will provide training for at least 2 PhD and 9 undergraduate student researchers who will gain interdisciplinary expertise in the hydrologic and biogeochemical sciences, solving problems of societal concern. Data and understanding gained in this project will be used as university class examples to discuss the linkages between land management, carbon cycling, and hydrologic response of forested ecosystems. This project will develop educational materials on watershed science that will reach nearly 6,000 K-12 students, 48 science teachers, and 40 pre-service students to enhance understanding of land cover-ecosystem interactions and knowledge of their local watersheds.Inland waters have recently been highlighted for their importance in global carbon pools and fluxes relative to terrestrial and marine systems. Dissolved organic matter (DOM) represents the largest fraction of organic carbon transported through stream networks, and much of this DOM enters streams in headwater forest locations. This project answers the call to ‘focus on better identifying human impacts on the transport and biogeochemical cycling of carbon by inland waters’ as outlined in the Second State of the Carbon Cycle Report, by: 1) Determining the role of forest harvesting in regulating DOM character in headwater streams; 2) Quantifying the influence of DOM character on stream ecosystem respiration; and 3) Identifying how components 1 and 2 interact to regulate spatial and temporal patterns of ecosystem respiration across forested headwater stream networks. This information will be used to create predictions that will then be confronted with data to improve models, and expose gaps in understanding to guide future field and lab experimentation. This project will develop a vertically integrated program of mentorship, education, and provide training for undergraduate and PhD students who will gain exposure to research, outreach, and professional development activities. Through collaboration with the College of Natural Science Education and Outreach Center, this project will develop a STEM kit on watershed science specifically targeted at K-12 schools with a high percentage of underrepresented students, and encourage these groups to pursue STEM pathways.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.