Algal bloom is a serious environmental problem in dam reservoirs and lakes, but methods for their prediction have low precision and current mitigation measures are insufficient for the prevention of algal bloom. Previous studies have shown that Fe is an essential nutrient for the growth of phytoplankton. Our previous studies have shown that Mn is an important nutrient for the growth of M. aeruginosa. Here, we examined the effects of five different metals, Fe, Mn, Zn, Co, and Mo, on the growth of M. aeruginosa, using water samples from dam reservoirs. The growth tests of M. aeruginosa were conducted with 32 patterns of media with different combinations of the five metals. The results demonstrated that M. aeruginosa hardly grew in media without Fe. In the case of media with Fe plus Mn, Co, or both, the growth of M. aeruginosa was promoted. On the other hand, the growth of M. aeruginosa was inhibited in the media with Zn. These findings suggest that Fe, Mn, and Co are important nutrients for the occurrence of algal bloom in dam reservoirs. |