Effects and control of metal nutrients and species on Microcystis aeruginosa growth and bloom

The effects and control of typical metal nutrients, copper, iron, and zinc, on the growth and bloom of Microcystis aeruginosa were investigated with a series of flask-shaking tests. The optimal concentrations of copper, iron, and zinc for algal growth were 0.001, 3-12, and 0.05 mg/L, respectively. The order of toxicity to the alga was Cu > Zn > Fe. The effects of the species, for a trace metal at the same concentrations, on the growth of M. aeruginosa were relatively remarkable. Ionic and complexation species induced more algal growth than the carbonate and sulfide-bound species. Changes in copper concentration and iron species were adopted to adjust and control the bloom of M. aeruginosa. Increases in copper concentrations significantly suppressed the M. aeruginosa bloom. The growth rate of M. aeruginosa slowed signifi-candy when ionic iron was replaced with sulfide-bound iron, and the control of bloom was remarkable. (C) 2018 Water Environment Federation