Harmful algal blooms (HABs) have increasingly become a problem in Lake Erie and the Saginaw Bay of Lake Huron since the 1990s. While problematic within the Great Lakes, algal blooms also occur in streams, rivers, and coastal regions around the globe. These blooms occur when the cyanobacterium Microcystis reaches a high density and begins producing a toxin known as microcystin. When ingested, this toxin imposes a risk to human health and thus, to coastal communities reliant on the lakes as their primary water source.

The ultimate goal of our project is to improve the reliability of the HAB forecasting model of NOAA and CIGLR within Lake Erie and Saginaw Bay and to enhance system usability among water utility managers. To achieve this overarching goal, we will address four related objectives:

1. How much nutrient reduction is required to control growth of harmful algae, and which forms of nutrients are responsible for triggering the onset of severe blooms?

2. Do invasive mussels exacerbate HABs by recycling nutrients that favor growth of harmful algae or by selectively consuming competitor species of phytoplankton?

3. Do harmful algae regulate their buoyancy in response to the ecological conditions of Saginaw Bay?

4. What information do public water systems need about harmful algal bloom toxicity to support continued delivery of high-quality drinking water during a bloom?

This research project will inform existing modeling efforts at CIGLR and GLERL by addressing key gaps in our understanding and improving their effectiveness in meeting the needs of their relative communities. It will provide early comparisons of the algal blooms of Saginaw Bay and Lake Erie which may be useful in making predictions and may also help inform future research and management efforts.