Figure 1.

(a) PCA-based grouping of lakes according to physicochemical parameters. The lakes marked in red are eutrophic (E), and lakes marked in green are meso-eutrophic (ME). (b) Principal component analysis (PCA) results. Projection of variables on the factor planes of PCA analyses of physicochemical variables. The variables in red squares are supplementary and have no influence on the principal components of the analysis. Cond.: conductivity [µscm⁻²], DOC: dissolved organic carbon [mgL⁻¹]. Chl a: chlorophyll a concentration [µgL⁻¹], HNF: heterotrophic nanoflagellates [cellmL⁻¹], TN: total nitrogen concentration [µgL⁻¹], Turbid: nephelometric turbidity [NTU], Temp.: temperature [°C], DO: dissolved oxygen concentration [mg O₂L⁻¹], TP: total phosphorus concentration [µgL⁻¹], PO₄³⁻: orthophosphate concentration [µgL⁻¹], mean TSI: mean trophic state index, BN: bacteria number [cellmL⁻¹].