Role of chemical and physical variables in regulating microcystin-LR concentration in phytoplankton of eutrophic lakes

• Published in: Canadian journal of fisheries and aquatic sciences Vol. 57; no. 8; pp. 1584 - 1593
• Main Authors: Kotak, Brian G, Lam, Angeline K-Y, Prepas, Ellie E, Hrudey, Steve E
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 01.08.2000; National Research Council of Canada; Canadian Science Publishing NRC Research Press
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Bacteria; Biological and medical sciences; Canada, Alberta; Cyanophyta; Environmental aspects; Environmental factors; Eutrophic lakes; Eutrophication; Fresh water ecosystems; Fundamental and applied biological sciences. Psychology; Lakes; microcystin-LR; Microcystins; Microcystis aeruginosa; Phytoplankton; Plankton; Synecology; Toxins; Water pollution; Canada; Alberta; North America; America; Alberta Canada; Microcystis aeruginosa; Environmental factor; Phosphorus; Trophic status; Biomass; Nitrogen; Eutrophication; Freshwater environment; Concentration measurement; Toxin; Microbial origin; Cyanobacteria; Lakes; Bacteria; Phytoplankton
• ISSN: 0706-652X; 1205-7533
• DOI: 10.1139/f00-091

A survey of eutrophic to hypereutrophic hardwater lakes in central Alberta was conducted to test the hypotheses that the concentration of the cyanobacterial toxin microcystin-LR (MC-LR) in phytoplankton is regulated by environmental factors that affect both the biomass of the main producer of the toxin, Microcystis aeruginosa, and the concentration of the toxin in the cells. Of all environmental factors examined, total phosphorus was the strongest correlate of both M. aeruginosa biomass and cellular MC-LR (expressed as micrograms per gram of M. aeruginosa). Microcystis aeruginosa biomass was also strongly negatively related to the total nitrogen to total phosphorus ratio (TN:TP) and inorganic nitrogen (NO 2 - + NO 3 - , NH 4 + ). A univariate regression model of TN:TP explained the most variation in MC-LR concentration (expressed as nanograms of cellular toxin per litre) in mixed phytoplankton communities. This study indicated that MC-LR dynamics in phytoplankton of lakes was related to changes in the concentration and ratio of phosphorus and nitrogen.