Date of Award

9-1-2025

Degree Type

Thesis

Degree Name

Master of Science (M.S.)

Department

Agricultural and Environmental Sciences

First Advisor

Reginald Archer

Abstract

Toxic algal blooms are an expanding issue for aquatic ecosystems because they are hazardous to human and environmental health. Algal blooms naturally occur from the combination of warm temperatures, sunlight, and abundant nutrients in water, but what triggers them to become harmful algal blooms (HABs) and begin synthesizing toxin is not well understood, and their threat to freshwater sources was not heavily researched until recently. Microcystin (MC), a freshwater algal toxin, is a HABs toxin which targets the liver and causes sickness and death in humans and animals (pets, livestock, and wildlife). Urban freshwater wetlands are among the most HAB threatened ecosystems due to their shallow depth, occurrence near anthropogenic nutrient runoff, and increasing global temperatures. This study collected water-quality, nutrient, and MC data from the Tennessee State University wetland from March 2022 through February 2024 from 8 monitoring locations to characterize the distribution of nutrients and MC, identify water quality conditions and/or nutrient concentrations present during MC detections, and determine whether specific conditions may influence HAB occurrence and toxicity in the wetland. Data from this study showed that MC occurrence has a positive correlation with temperature and phosphate and a negative correlation with dissolved oxygen and water level; and toxicity is likely primarily influenced by available nitrate during the growing season. These findings provide a better understanding of the conditions surrounding HABs and insight on their triggers to enable better preparation for toxic blooms and/or potential preventative action prior to occurrences.

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