Microcystis

Summary

The chapter focuses on features of Microcystis influencing its success in forming water blooms world-wide. The topics covered included its life strategy, life cycle, cell structure and function, together with the environmental variables especially important at different stages in its life cycle. A polyphasic approach to its taxonomy has shown the complexity of the situation in nature and in the laboratory. While the genus is distinct enough to be recognized, we suggest using “morphospecies” for descriptions of species. The increasing literature on the benthic phase of the life cycle in temperate regions is reviewed, together with the subsequent reinvasion of colonies to the plankton. Temperature and bioperturbation appear to be among the most important factors influencing the latter stage and there is no evidence for any sort of time clock. There has been a shift during recent years from considering extracellular and intracellular peptides, alkaloids and other biologically active compounds largely with respect to their human impact, especially toxicity, to a broader one of understanding their ecological role. Partly associated with this the process of colony formation has become an important area of study. Morphological, ecophysiological approaches combined with molecular genetic and sensitive instrumental methods can open a new view on signal transduction and intercellular communication within individual colonies and whole populations. Such information will not only aid the understanding of colony formation, but also bloom formation, populations dynamic and the competitive advantages of various “morphospecies”.