Associations of invasive cyanobacterial species and phytoplankton community structure with abiotic influences in post-glacial temperate lakes under climate change

This study conducted in Mazurian and Suwałki Lakelands (Poland), investigated the composition and distribution of phytoplankton species, currently existing invasive Cyanobacteria, and their linkages with various environmental parameters. Water and phytoplankton samples were collected from twenty-five lakes in the summer of 2023 to achieve the aims. In the study, crucial ecological influences such as pH, conductivity, dissolved oxygen, nutrient concentrations, and water temperature values were measured and their associations with phytoplankton community structure were described. In addition, the Shannon diversity index, Pielou’s evenness, Euclidean distance analysis, frequency analysis, and redundancy analysis have been applied to interpret the obtained data. In total 325 phytoplankton species were recorded, with the most abundant class being Cyanophyceae represented by 170 taxa. Although they had relatively low biomass, all of the investigated invasive cyanobacterial species ( Raphidiopsis raciborskii , Chrysosporum bergii , and Sphaerospermopsis aphanizomenoides ) have been identified in several water bodies. The Shannon diversity index showed that the highest diversity was found in one of the most eutrophic lake (Rekąty). Euclidean distance analysis described the highest similarity between two lakes with similar trophic status in Suwałki Lakeland (Przerośl and Hołny). RDA analysis revealed the positive correlations between Chlorophyceae and pH; Cyanophyceae and dissolved oxygen concentration.