SOP 4. Analysis of picocyanobacteria abundance in epifluorescence microscopy

Picocyanobacteria, the smallest cyanobacteria in the size range 0.2-2.0âEUR?μm, are both numerous and ubiquitous in freshwater, brackish, and marine environments. Their contribution to primary production decreases with the increase of trophic level; however, they were shown to form persisting blooms in some eutrophicated coastal lagoons. These findings suggest that picocyanobacteria can be a new potential, and until now overlooked, source of cyanotoxins and other bioactive compounds in freshwaters and marine environments and that microcystin occurrence in marine environments may be more common than recognized so far.