Impact of turbidity, temperature, and total nitrogen on cyanobacterial blooms in Lake Ypacaraí (Paraguay)

Lake Ypacaraí faces a severe pollution problem, resulting in frequent cyanobacterial blooms. This study focused on identifying the physicochemical parameters positively correlated with these blooms during the 2015–2016. Six sampling points were selected in the lake, and measurements were taken for cyanobacteria and six physicochemical parameters: transparency, turbidity, water temperature, pH, total Kjeldahl nitrogen (TKN), and total phosphorus (TP). Nine species of cyanobacteria were identified, Microcystis aeruginosa being the most frequent and dense. The maximum concentrations of TKN (3.51 mg L−1) and TP (1.04 mg L−1) indicated an advanced state of eutrophication in the lake. Canonical multivariate analysis revealed that TKN and temperature significantly positively correlated with M. aeruginosa blooms. These results suggest that water quality management in the lake must focus on reducing nitrogen load to mitigate cyanobacterial blooms and support the ecosystem's recovery.