Authors: Asia Dowtin*, Michigan State University, Delphis Levia, University of Delaware, Afton Clarke-Sather, University of Minnesota Duluth
Topics: Environmental Science, Water Resources and Hydrology
Keywords: atmospheric deposition, throughfall, nutrient cycling, urban forestry
Session Type: Paper
Start / End Time: 4:30 PM / 6:10 PM
Room: Congressional A, Omni, West
Presentation File: No File Uploaded
Atmospheric deposition serves as a primary source of nutrients and pollutants to urban forested ecosystems. Although spatial variability in atmospheric deposition to forests is generally considered within the context of the urban-to-rural gradient, spatial heterogeneities often exist in land use within heavily developed sectors of a metropolitan region, which may yield notable differences in the quantity and spatial distribution of nutrient loads deposited to and cycled within remnant urban woodlots. In the current study, event-based in situ sampling of throughfall was conducted in suburban and urban remnant woodlots in metropolitan Wilmington, Delaware and utilized to characterize spatial differences in solute flux within urban forests. Throughfall elemental fluxes were quantified for nitrate-nitrogen (NO3-N), calcium, potassium, sulfur, magnesium, manganese (Mn), and zinc (Zn) between April 2016 and August 2017. Observations indicate that throughfall solute fluxes within the suburban site were significantly higher than those within the urban sites for NO3-N, Zn, and Mn, with Mn throughfall fluxes at the suburban woodlot exceeding those at the urban sites by as much as a factor of five. Higher throughfall flux observations at the suburban site are likely attributable to proximity to multiple forms of urban land use, including rail lines and high-volume roadways. Results suggest the underlying importance of considering the distance of an urban woodlot to various forms of land use (and thus emissions), rather than solely referencing its location along an urban-to-rural gradient, as a means by which to improve our understanding of nutrient and pollutant cycling within urban forested ecosystems.