Competitive exclusion of toxic cyanobacterial species by an allelopathic strain of Phormidium

Blooms of freshwater toxic cyanobacteria are a growing environmental health problem, enhanced by anthropogenic eutrophication and climate change. A variety techniques were tested for their remediation, from physical methods using artificial mixing or flocculation, to chemical employing synthetic natural compounds, as well constructed wetlands. In this work, we conducted an evaluation at microcosm scale the usefulness allelochemicals produced strain filamentous Phormidium sp. bioremediation proliferations four strains (Cylindrospermopsis raciborskii, Chrysosporum ovalisporum, Anabaena Nodularia sp.). Allelochemicals belong portoamides compounds family. Their effect was in bioassays cell-free filtrate, results showing that all sensitive. addition, performed phosphate-limited long-term competition experiments continuous cultures, which co-cultured with each cyanobacterial strains. The purpose these later demonstrate allelopathy not resource responsible ecological exclusion strains, also employ higher population abundances test effectiveness allelochemicals. Before that, needed estimate competitive ability species limit employed (phosphate). clearly better competitor phosphate than sp., worse very similar C. raciborskii ovalisporum. Only case could caused allelopathy. However, rapid shown our suggests main cause cases. An inter-specific model including only allelopathic interaction able accurately describe patterns dynamics observed experiments.