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School of Environment and Natural Resources


Graduate Exit Seminar - Katherine Gaffney

Plan to join Katherine Gaffney's graduate exit seminar on April 1, 2024, at 9:30 am in Kottman Hall 370 or via Zoom. Katherine will present, "Spatial and Seasonal Variability of Dissolved Organic Matter and Nitrogen in Lake Erie Tributaries."

Abstract: It is important to understand how environmental factors drive variability in aquatic nutrient cycling in streams. Controls on variability in production and transformation of dissolved organic matter (DOM), a carbon-based nutrient, are not well understood on spatial scales spanning many streams. This knowledge gap leaves questions as to how environmental factors influence DOM characteristics. In water year 2023, we investigated nitrogen and carbon chemistry seasonally in 80 tributaries on the United States side of Lake Erie. Watershed area and modeled discharge had no clear effect on total dissolved nitrogen (TDN) or DOM concentrations. Land use was a significant factor influencing stream chemistry; watersheds with different dominant land uses produced different seasonal chemistry patterns and had different environmental factors influencing stream chemistry. In watersheds dominated by agricultural land use, nitrate was the dominant form of nitrogen contributing to high TDN concentrations, likely driven by fertilizer use. DOC concentration and chemistry varied moderately with season and had slightly different seasonal trends in watersheds with different dominant land covers, likely due to differences in DOM sources and transformations.

Advisor: Dr. Rachel Gabor