Results of Redundancy Analysis on the relationships between environmental explanatory variables (vectors) and phytoplankton variables (responses), considering (A) the total phytoplankton cell density and (B) the mean phytoplankton cell volume data during the decade 2006–2015 in Bidighinzu Lake in summer. Eigenvalues of the first two axes are indicated by λ1 and λ2. Asterisks indicate statistical significance (*p < 0.05; **p < 0.01; ***p < 0.001) of environmental variables. WEMOi, Western Mediterranean Oscillation index; AirTem, air temperature; Rain, rainfall; Zmix/Zeu, mixing zone and euphotic zone ratio; WatTem, water temperature; Si-SiO4, silicate; P-PO4, orthophosphate; TP, total phosphorous; N-NO3, nitrate; N-NO2, nitrite; N-NH4, ammonia; DIN, dissolved inorganic nitrogen; TN, total nitrogen; TON, total organic nitrogen; Bac, Bacillariophyceae; Chl, Chlorophyceae; Chr, Chrysophyceae; Con, Conjugatophyceae; Cry, Cryptophyceae; Cya, Cyanophyceae; Dino, Dinophyceae; Eug, Euglenophyceae; TotDens, total phytoplankton density; MeanVol, mean cell volume of the whole phytoplankton community.