formbloom_conestogo-2017HAB

Abstract

\1. The increasing prevalence of cyanobacteria-dominated harmful algal blooms is strongly associated with nutrient loading and changing climatic patterns. Changes to precipitation frequency and intensity, as predicted by current climate models, are likely to affect bloom development and composition through changes in nutrient fluxes and water column mixing. However, few studies have directly documented the effects of extreme precipitation events on cyanobacterial composition, biomass, and toxin production.

\2. We tracked changes in a eutrophic reservoir following an extreme precipitation event, describing an atypically early toxin-producing cyanobacterial bloom, successional progression of the phytoplankton community, toxins, and geochemistry.

\3. An increase in bioavailable phosphorus by more than 27-fold in surface waters preceded notable increases in Aphanizomenon flos-aquae throughout the reservoir approximately 2 weeks post flood and ~5 weeks before blooms typically occur. Anabaenopeptin-A and three microcystin congeners (microcystin-LR, -YR, and -RR) were detected at varying levels across sites during the bloom period, which lasted between 3 and 5 weeks.

\4. Synthesis and applications: These findings suggest extreme rainfall can trigger early cyanobacterial bloom initiation, effectively elongating the bloom season period of potential toxicity. However, effects will vary depending on factors including the timing of rainfall and reservoir physical structure. In contrast to the effects of early season extreme rainfall, a mid-summer runoff event appeared to help mitigate the bloom in some areas of the reservoir by increasing flushing.

citation: Megan L. Larsen, Helen M. Baulch, Sherry L. Schiff, Dana F. Simon, Sébastien Sauvé, and Jason J. Venkiteswaran. Extreme rainfall drives early onset cyanobacterial bloom. FACETS. 5(1): 899-920. https://doi.org/10.1139/facets-2020-0022

Co-authors

Megan L. Larsen, Wilfrid Laurier University, mlarsen@wlu.ca, ORCID 0000-0002-4155-1293

Helen M. Baulch, University of Saskatchenwan, hbaulch@usask.ca, ORCID 0000-0001-9018-4998

Sherry L. Schiff, University of Waterloo, ORCID 0000-0002-7704-7304

Dana Simon, Université de Montréal

Sebastien Sauve, Université de Montréal

Jason Venkiteswaran, Wilfrid Laurier University, jvenkiteswaran@wlu.ca, ORCID 0000-0002-6574-7071

Data sources

Figshare Project DOI: https://doi.org/10.6084/m9.figshare.7811963.v1

Grand River Conservation Authority (GRCA): https://waterdata.grca.ca

Funding sources

• Global Water Futures: FORecasting tools and Mitigation options for diverse BLOOM-affected lakes (FORMBLOOM)
• Genome Canada and Genome Quebec: Algal Blooms, Treatment, Risk Assessment, Prediction and Prevention through Genomics (ATRAPP)

Keywords

cyanobacterial bloom, harmful algal bloom, Ontario, reservoir, extreme rainfall

Geographic Coverage

• Geo Bounding Box (west): -80.804541
• Geo Bounding Box (east): -80.680523
• Geo Bounding Box (north): 43.741943
• Geo Bounding Box (south): 43.665381

Additional information and support

• Sensitive Data Flag - Human Participants: NO
• Sensitive Data Flag - Indigenous Partnerships: YES
• Sensitive Data Flag - Government Partnerships: NO
• Sensitive Data Flag - Industry Partnerships: YES
• Access Restrictions

Repo content information

data

data used for production of this work

code

Scripts for processing raw data into cleaned data, outside derived code, and user derived code.

src

source code for themes and interpolation plots

output

Figures and tables produced from analysis.