In the last decades, the cyanobacterium Dolichospermum lemmermannii showed an increasing spread to Southern Europe, raising serious concerns due to its ability to produce cyanotoxins. The widening of its geographic distribution and the observation of strains showing high optimum temperature underline its ecological heterogeneity, suggesting the existence of different ecotypes. To investigate its biogeography, new isolates from different European water bodies, together with strains maintained by the Norwegian Institute for Water Research Culture Collection of Algae, were genetically characterised for the 16S rRNA gene and compared with strains obtained from public repositories. Geographic distance highly influenced the differentiation of genotypes, further suggesting the concurrent role of geographic isolation, physical barriers and environmental factors in promoting the establishment of phylogenetic lineages adapted to specific habitats. Differences among populations were also examined by morphological analysis and evaluating the toxic potential of single strains, which revealed the exclusive ability of North European strains to produce microcystins, whereas the populations in Southern Europe tested negative for a wide range of cyanotoxins. The high dispersion ability and the existence of toxic genotypes indicate the possible spread of harmful blooms in other temperate regions.

在过去的几十年中，蓝单胞菌蓝单胞菌表现出越来越多的扩散到南欧，由于其产生氰毒素的能力而引起了人们的严重关注。其地理分布的扩大和最佳温度的菌株的观察强调了其生态异质性，表明存在着不同的生态类型。为了研究其生物地理学，对来自欧洲不同水体的新分离株，以及由挪威水藻研究所水藻培养物保藏中心保存的菌株，进行了16S rRNA基因的遗传鉴定，并与从公共资源库获得的菌株进行了比较。地理距离在很大程度上影响了基因型的分化，进一步表明了地理隔离的同时作用，物理障碍和环境因素，以促进建立适应特定栖息地的系统谱系。还通过形态分析和评估单个菌株的毒性潜力检查了种群之间的差异，这揭示了北欧菌株产生微囊藻毒素的排他性能力，而南欧的人群对多种氰毒素测试为阴性。高分散能力和有毒基因型的存在表明有害水华可能在其他温带地区传播。而南欧的人群对多种氰毒素的检测结果均为阴性。高分散能力和有毒基因型的存在表明有害水华可能在其他温带地区传播。而南欧的人群对多种氰毒素的检测结果均为阴性。高分散能力和有毒基因型的存在表明有害水华可能在其他温带地区传播。