Blue-green algae mitigation strategies for urban lakes

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Cyanobacteria, commonly known as blue-green algae, are naturally occurring microscopic organisms that may release cyanotoxins into freshwater systems. These toxins pose a serious public health risk as exposure through skin contact, ingestion of lake water, or contaminated drinking water or food may cause symptoms impacting both animals (livestock and pets) and humans. These risks range from minor irritation to more serious illness and, in worst case scenarios, can be fatal.Cyanobacteria occur worldwide, in calm, nutrient-rich waters, allowing algal blooms. These blooms may occur at any time of year but are more common during summer and early fall, creating bad odors, water discoloration, accumulate as a scum on the surface of the water, and releasing toxins that may be harmful to humans and aquatic biota. The expectations are that blooms will increase in frequency and duration in urban lakes due to warming temperatures associated with climate change.With the increasing incidence of cyanotoxins, interest is focusing on understanding the pathways of factors which contribute to formation of cyanotoxins and ultimately, opportunities to manage urban lakes and hence insights to decrease the potential for algal blooms to occur (e.g. manage/decrease nutrient loads, consider physical and chemical activities to reduce the blooms, and develop scientific knowledge using modern techniques such as microbial source tracking, and create tools to assess their magnitude and potential). Currently, models to specifically predict harmful algal composition and toxicity are lacking and improved knowledge of the effectiveness of possible control measures are needed.This research will focus on a case study application to Fairy Lake, a 26 ha Provincially Significant Wetland in the Town of Halton, Ontario where the algal growths are substantial and a considerable history of data are available. Fairy Lake is ideal for this research, given the interested parties, the proximity allowing relatively easy access, and the expertise within the proposed research team.