ECOLOGY AND TOXICITY OF CYANOBACTERIA HARMFUL ALGAL BLOOMS IN MINNESOTA LAKES

Though cyanobacteria are a natural component of phytoplankton communities, increased monitoring continues to convey the importance of understanding physical, chemical, and biological drivers of toxigenic genera. Cyanobacteria harmful algal blooms (cHABs) continue to cause concerns related to human and ecological health despite mitigation efforts. To better understand cHAB ecology and toxicity, we sampled six Minnesota lakes, part of the MN Sentinel Lakes Program, with varying latitudes, land uses, mixing types, and trophic states to determine lake-specific drivers of cyanobacteria phenology. A multidisciplinary approach was taken by integrating traditional microscopy techniques, metagenomic analyses, and nutrient quantification (including nitrogen fixation rates) to determine genera abundance and toxin production capabilities. Sampling surveys occurred from May through October 2020 and 2021. Cyanobacteria genera were ubiquitous among sample lakes, including northern, oligotrophic systems; and regular, nuisance blooms occurred in a southern, eutrophic lake, Peltier. Lakes showed divergent nutrient deficiency statuses (nitrogen vs phosphorus limited or balanced growth), variability in nitrogen fixation rates and microcystin concentrations, and strain-specific toxin production capabilities. We will present a comprehensive overview of the project’s findings and the implications of understanding the importance of cHAB community composition and strain-specific adaptations on toxin production capabilities across varying lake systems.

Primary Presenter: Leah Schleppenbach, Natural Resources Research Institute (egan0133@d.umn.edu)

Authors:

Leah Schleppenbach, Natural Resources Research Institute, University of Minnesota Duluth  (egan0133@d.umn.edu)

Kaela Natwora, Large Lakes Observatory, University of Minnesota Duluth  (natwo001@umn.edu)

Cody Sheik, Large Lakes Observatory, University of Minnesota Duluth  (cssheik@d.umn.edu)

Chris Filstrup, Natural Resources Research Institute, University of Minnesota Duluth  (filstrup@d.umn.edu)