Assessing Eutrophication Vulnerability as an Indicator of Cyanobacteria Presence in Kejimkujik National Park

Abstract

Kejimkujik National Park (KNP) and National Historic Site (Nova Scotia, Canada) is home to numerous lakes that support a multitude of recreational activities and aquatic habitats. The park is comprised of camp sites, canoeing routes, and hiking trails, making it a popular tourist attraction during the summer months. Aquatic systems in the park not only support these recreational activities, but also support diverse organisms that are important to the park’s ecosystem. This thesis was the first study to assess the cyanobacterial populations within KNP. The objectives of this study were to identify lakes within the park that are susceptible to cyanobacteria blooms. Several factors could influence the proliferation of cyanobacteria in KNP, including nutrient abundance, light availability, water temperature, mixing regimes, and flushing rates. This study involves a phosphorus loading model, which uses publicly available spatial and water quality data, to characterize the lakes in KNP based on their eutrophication vulnerability, using the factors known to contribute to harmful cyanobacterial blooms. The results of the model were compared to information collected from a park-wide cyanobacteria sampling program and toxin survey conducted in 2023 to assess the applicability of this model for identifying lakes vulnerable to blooms. Next generation MiSeq illumina sequencing results indicate that cyanobacteria were present in small abundances in 10 of the 16 study lakes within the park, but little is known about whether these photosynthetic bacteria populations could proliferate and form blooms that could be harmful to humans and other animals. Three of the study lakes contained potentially toxin-producing cyanobacteria of the order Nostocales. Anatoxins and microcystins were detected in small quantities in several locations in the park. Water quality parameters collected from 2008 to 2021 indicate that cyanobacteria were primarily present in oligotrophic lakes. Cyanobacteria were additionally only shown to exist within certain thresholds of certain water quality parameters. Cyanobacteria were only found in lakes with a total phosphorus concentration between 4 to 10 μg/L, and a total organic carbon concentration between 2 to 5 mg/L. More research needs to be conducted to determine exactly what is driving the cyanobacteria proliferation in KNP.