Defense Date

2026

Document Type

Thesis

Degree Name

Master of Science

Department

Biology

First Advisor

Paul Bukaveckas

Abstract

Lakes are an integral part of urban and suburban communities, providing ecological, recreational, and public health benefits. Many of these lakes are located in densely populated areas and are subject to urban influences on water quality. Algal toxins and Escherichia coli are two common recreational concerns. Algal toxins come from harmful algal blooms that are influenced by nutrient availability and temperature, while bacteria are often introduced through run-off and animal waste. Sampling every 3-4 weeks from May-October 2025 allowed for the assessment of seasonal patterns and site-specific differences across nine lakes in the Richmond area. The highest bacterial concentrations appeared on the dates with the highest average rainfall, indicating a strong stormwater run-off influence. Four of the nine (44%) lakes have median concentrations at, or above, the recreational safety threshold established by the Virginia Department of Health. Chlorophyll-a varied widely among lakes and throughout the warm season, with anthropogenic recreational disturbance of bottom sediments consistently increasing chlorophyll-a, total nitrogen, and total phosphorus. Microcystin levels remained below recreational safety levels at all sites throughout the entire season. The relationship between chlorophyll-a and microcystin strengthened under disturbed conditions, which suggests that benthic sources contribute to toxin production. Presently, E .coli poses the most immediate public health concern in Richmond’s urban lakes, but disturbance’s impact on algal biomass in the water column and sediment/nutrient dynamics underscores the importance of regular monitoring to identify and mitigate harmful algal blooms and protect community health in these urban freshwater systems.

Rights

© The Author

Is Part Of

VCU University Archives

Is Part Of

VCU Theses and Dissertations

Date of Submission

5-8-2026

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