Recent spread of Raphidiopsis raciborskii in the lake district south of the Alps

In recent years, there has been a rise in cyanobacterial blooms, and climate warming is believed to be a key driver sustaining these changes. Climate change may affect the geographic distribution of potentially toxigenic species and cyanobacteria, leading to the appearance of new threats in previously unexposed areas. Recently, the potentially toxic cyanobacterium Raphidiopsis (Cylindrospermopsis) raciborskii, known for forming blooms, has increased its presence, particularly in temperate regions. In this work, we expanded the knowledge about the distribution of R. raciborskii in Northern Italy. Specifically, we reported new observations recorded during the last decade based on investigations carried out in the framework of scientific and government monitoring and large biogeographical surveys carried out on the whole Alpine Space area. The detection of R. raciborskii in Northern Italy highlights the importance of closely monitoring freshwater quality and implementing measures to prevent the spread of harmful organisms