The Effect of Arsenate on the Growth Rate of Microcystis aeruginosa

Exposure of arsenate on Microcystis aeruginosa FACHB905 preconditioned to phosphate starvation was performed under different phosphate regimes.It was designed to explore the effects of arsenate and phosphate on the growth rate of M.aeruginosa FACHB905 isolated from Dianchi Lake when the extracellular phosphate or arsenate concentration was changeable.The results showed that the growth rates increased along with the increase additional amount of phosphate in the medium when the phosphate concentration lower than 40 μg/L,was the limited factor for the cyanobacterial growth.It was shown that the extracellular phosphate concentration had no reference to the threshold doses of M.aeruginosa FACHB905 to arsenate,and the threshold doses was 106.5μg/L,however,the EC50,48h value increased along with the increase phosphate concentration.In this study,arsenate had no effect on the parameters of phosphate uptake kinetics,which gave some evidence indirectly that M.aeruginosa FACHB905 had the ability of discriminating between phosphate and arsenate.It was found most helpful on complete understanding of microcystis bloom formation in Dianchi Lake with high environmental background values of arsenic.