Drivers of Spatiotemporal Patterns in Cyanobacterial Fluorescence in Callander Bay, Lake Nipissing

Session: 41a. - Great Lakes Harmful Algal Blooms Research from Watershed Influence to Ecosystem Effects

Joel Harrison, North Bay-Mattawa Conservation Authority, [email protected]
Dan Walters, Nipissing University, [email protected]
April James, Nipissing University, [email protected]
Sue Miller, North Bay-Mattawa Conservation Authority, [email protected]

Abstract

Callander Bay is a large (~1200 ha), polymictic, meso-eutrophic (avg. TP = 21 µg/L) embayment of Lake Nipissing that is the municipal water source for Callander, Ontario.  The bay has a relatively-long water residence time (~0.7 yr), exhibits limited hydrological exchange with the greater lake, and periodically experiences toxic cyanobacterial blooms that have been designated a significant threat to source water under the Clean Water Act.  Significant contributors of phosphorus to the bay include the Wasi River, a littoral wetland receiving discharge from municipal sewage lagoons, and (presumably) the bay’s sediments.  A multi-wavelength submersible fluorometer (bbe FluoroProbe) was used to quantify temporal and spatial patterns in phytoplankton biomass and community composition within the bay in 2017.  This talk (1) discusses the seasonal transition of the phytoplankton community from a state of chromophyte (diatom, chrysophyte, and/or dinoflagellate) dominance to one of cyanobacterial dominance, (2) characterizes variation in the magnitude and spatial distribution of cyanobacterial biomass within the bay, and (3) examines the linkages between these patterns in the phytoplankton community and possible explanatory factors such as variation in phosphorus concentrations, phosphorus sources, and meteorological factors.

1. Keyword
phytoplankton

2. Keyword
harmful algal blooms

3. Keyword
drinking water

4. Additional Keyword
fluorescence