Global expansion of toxic and non-toxic cyanobacteria: effect on ecosystem functioning

The recent invasion and proliferation of toxic cyanobacteria in diverse aquatic habitats is a well-known worldwide phenomenon. The expansion of cyanobacterial blooms have the potential to significantly alter the structure of the native community and to modify ecosystem functioning. Public and scientific attention was primarily given to the effect on the water quality due to a variety of toxic compounds that some species produce. However, the expansion of toxic and non-toxic cyanobacteria to a wide geographic range may have an impact on the ecosystems, trophic cascades and geochemical cycles. Here we briefly summarize the geographic expansion of cyanobacteria species. We further deliberate the physiological advantages of the invading cyanobacterial species and the ecological effect of cyanotoxins. We discuss recent studies on the contribution of cyanotoxins to the invasion process and the impact toxin producing cyanobacteria have on their newly invaded habitats, the effect of alien cyanobacteria on zooplankton and fish and on the diversity and complexity of the microbial community.