Table 1.
Morphological and physical characteristics for the three study lakes.
Figure 1.
Concentration of nutrients (μM) from April to October in the three study lakes.
A) TP, B) SRP, C) TN, D) DON, E) NH4+, and F) NO3−+NO2−. BRO INT, integrated samples from the epilimnion of lake Bromont; BRO META, samples from the metalimnion of lake Bromont; PSF, Petit Lac St. François; WAT, Lake Waterloo.
Figure 2.
Cyanobacterial biomass and microcystin concentrations from May to October in the three study lakes.
A) Cyanobacterial biomass (μg·L−1); and total microcystin concentration expressed as B) μg·L−1 and C) μg·g−1 dry weight.
Table 2.
Average biomass (μg·L−1) and mean percent of total cyanobacterial biomass (% cyano) of the dominant cyanobacterial taxa observed in the three study lakes across all sampling dates.
Figure 3.
Temporal variation of total MC concentration measured by ELISA (full squares) and MC congeners measured by HPLC (stacked bars), from May to October in the three study lakes.
A) Lake Bromont, B) Waterloo, and C) Petit Lac St. François.
Figure 4.
Principal component analysis (PCA) (scaling 1) of environmental variables, cyanobacteria species and MC congeners.
The length of a vector is proportional to the importance of the descriptor to the sites. (IB; Bromont integrated epilimnion, MB; Bromont metalimnion, PSF; Petit Lac St. François, WAT; Waterloo). Cyanobacterial species are in italics, MC variants are in bold. A. cra; Anabaena crassa, A. pla; Anabaena planktonica, A. smi; Anabaena smithii, A. spi; Anabaena spiroïdes, A. flo; Aphanizomenon flos-aquae, M. aer; Microcystis aeruginosa, M. wes; Microcystis wesenbergii, M. spp.; Microcystis spp., P. aga; Planktothrix agardhii, S. spp.; Spirulina spp.
Figure 5.
Redundancy analysis (RDA) of environmental variables, cyanobacteria species and MC congeners.
RDA performed with forward selection by permutation (n-perm = 999) on A) Species biomass as explanatory variables for MC congener composition (R2adj. = 0.40, p = 0.001) where combined Microcystis aeruginosa, Microcystis wesenbergii and Aphanizomenon flos-aquae explain 40% of the variation in MC congener concentration; and B) Environmental factors as explanatory variables for cyanobacterial species biomass (R2adj. = 0.28, p = 0.001) where combined TN and DON explain 28% of the variation in species composition (for species abbreviations, see legend in Figure 4).