Date of Award

Spring 5-9-2022

Document Type

Thesis

Degree Name

Bachelor of Arts

Department

Biology

First Advisor

Ruth Heindel

Abstract

Due to the potential negative ecosystem impacts from increased atmospheric nitrogen (N) and dust deposition, there has been a vast amount of research on the topic. However, many questions remain about the spatial variation in N and dust deposition, as well as ecosystem impacts, across land-use gradients, especially agricultural-to-urban gradients. To address this knowledge gap, we measured bulk atmospheric N deposition, dust deposition, and ecosystem impacts along an agricultural-to-urban transect at four sites in Ohio, U.S., during the summer of 2021 (for nine weeks). We found no significant differences in N deposition from agricultural to urban sites during the summer period of this study, but average weekly total inorganic N loads varied from 0.167 kg ha-1 at the agricultural/suburban site to 0.199 kg ha-1 at the urban site. Dust flux was significantly elevated at the urban site (20.48 +/- 9.52 mg m-2 day-1) compared to two of the other sites (11.11 +/- 6.11 to 11.19 +/- 5.20 mg m-2 day-1), and we found evidence for the ‘urban scrubber effect’ causing elevated bulk deposition pH at the urban site. N concentrations in two plants (Solidago canadensis and Andropogon gerardii) and in the soil were all highest at the most urban site, and C:N ratios were lowest at the most urban site for both plants and soil. Our results indicate that agricultural and urban areas in Ohio possibly have similar N deposition loads; however, future work should explore this hypothesis further. Ecosystem impacts varied from agricultural to urban sites even though no significant differences in N deposition were observed, indicating that even small changes in N deposition can have significant impacts and these impacts can differ among species. Our results suggest S. canadensis may have a competitive advantage in environments with excess N, which implies that elevated N deposition could decrease species biodiversity in Ohio, especially in urban areas.

Rights Statement

All rights reserved. This copy is provided to the Kenyon Community solely for individual academic use. For any other use, please contact the copyright holder for permission.

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