Abstract
In the present study, we investigated the feasibility of preventing cyanobacterial dominance using the anti-cyanobacterial allelopathic effect of the submerged macrophyte Myriophyllum spicatum. When the cyanobacterium Microcystis aeruginosa and the green alga Scenedesmus obliquus were cultivated at 25°C and 30°C in a mixed culture system, M. aeruginosa dominated; however the addition of eight allelochemicals equivalent to 288 g dry wt·m-3 M. spicatum specifically inhibited the growth of M. aeruginosa and maintained it at less than that of S. obliquus, thereby confirming the prevention of M. aeruginosa dominance. As for the factors affecting the anti-cyanobacterial allelopathic effect, the competition with S. obliquus was the factor magnifying the inhibition of M. aeruginosa growth by the eight allelochemicals. Comparing the inhibitory effects observed at 25°C and 30°C, a lower temperature was preferable for the inhibition of M. aeruginosa growth by the eight allelochemicals.
