Date of Award
Master of Science (MS)
Catherine M. O'Reilly
Urban stream ecosystems are faced with high input levels of nitrogen (N) and phosphorus (P) from anthropogenic activities. N and P are important to plant growth and stream health; however, high levels can lead to algal blooms and eutrophication, a harmful effect to both aquatic life and water quality. Common urban sources of N and P include fertilizer, atmospheric deposition, stormwater outfall, and leaf-litter decomposition. Common urban stream features such as a flashier hydrograph, altered channel stability and morphology, increase in nutrient output (such as N and P), and heat retention, have been shown to result in an overall decrease in stream biodiversity. High input levels of N are seen within the Mississippi River Basin in the form of nitrate. In urban systems, estimates of loading of N and P into the Mississippi River Basin range from 7-9% for total N and 12-16% for P.
This study focused on urban stream nutrient uptake along concrete-lined channels. Tributaries of Sugar Creek in Bloomington-Normal, IL, served as the study area. I hypothesized that concrete-lined channels limit nutrient uptake and maintain higher concentrations of N and P uptake. Measuring nutrient uptake involved short-term N and P additions. Samples tested for nitrate were analyzed on a Dionex ion chromatograph, while samples tested for dissolved reactive phosphate were analyzed following the molybdate method using spectrophotometry. Both N and P uptake velocities measured higher along urban concrete streams as compared to studies conducted in other environments such as deserts and forested areas. In addition, monthly uptake velocities were compared across the study sites, resulting in greater P uptake velocities over N uptake velocities.
Many urban streams were modified to manage for hydrology, potentially altering nutrient processing. Thus, quantifying nutrient uptake along a modified streambed will identify how N and P are retained within a stream ecosystem and have implications for stream system restoration.
Sheffield, Nicolette A., "Nitrogen and Phosphorus Uptake in an Urban Stream Ecosystem" (2019). Theses and Dissertations. 1111.