Autecology of Cylindrospermopsis raciborskii (Woloszynska) Seenayya et Subba Raju

Aim: Cylindrospermopsis raciborskii (Woloszynska) Seenayya and Subba Raju, also called Raphidiopsis raciborskii, is a diazotrophic and filamentous cyanobacterium with terminal heterocytes, belonging to the order Nostocales. It has been the focus of several studies due to its toxicity and wide geographic distribution. Methods: To understand its autecology and to identify the key factors that control its dominance, the present review discusses, based on recent publications, whether the expansion of this species is a result of a high metabolic plasticity or the existence of distinct ecotypes. Results: Among the factors influencing C. raciborskii growth are its ability to survive in wide temperature, light intensity and pH ranges; to dominate in both stratified and mixed environments; to tolerate oligohaline conditions; to produce and secrete allelopathic substances; suffer little herbivore pressure; and although associated with a eutrophic environment, to tolerate low concentration of phosphorus and nitrogen with a high affinity for ammonia. Conclusions: Due to these differences in the environmental conditions of growth and development found in various studies, we suggest the existence of different ecotypes that will predominate under specific environmental conditions as the most appropriate hypothesis.