HgCl_2对太湖不同季节优势藻生长的影响

Effects of HgCl_2 on Growth of Dominant Algae of Taihu Lake in Different Seasons

为探讨HgCl2对不同季节湖泊生态系统的影响,以太湖不同季节优势藻——舟形藻(冬季)和惠氏微囊藻(夏季)为对象,研究不同浓度的HgCl2对2种优势藻生长的影响以及2种藻对HgCl2的吸附能力.结果表明:舟形藻对HgCl2暴露刺激比惠氏微囊藻更为敏感,在c(HgCl2)为1×10-9～1×10-7molL的范围内,HgCl2对惠氏微囊藻的生长表现出低浓度促进、高浓度抑制的效应;而对舟形藻则表现出明显的抑制作用,并且抑制作用随着c(HgCl2)的升高而更加明显.吸附试验结果表明,惠氏微囊藻对HgCl2的吸附率为88.4%～98.8%,舟形藻为87.1%～97.5%,并且吸附率和吸附量均随着c(HgCl2)的升高而逐渐增大,说明这2种藻对HgCl2都有极高的吸附效应.吸附了HgCl2的藻成为一个潜在的汞蓄积库,可对水环境产生危害.

The effects of HgCl2 on lake ecosystems in different seasons were studied by investigating the influence of HgCl2 with different concentrations on the growth of two algal species and their adsorption capacities to HgCl2.The two species,Navicula and Microcystis wesenbergii,have growth advantages in winter and summer,respectively.The results showed that Navicula was more sensitive than Microcystis wesenbergii to the mercury exposure.When the concentration of HgCl2 was in the range of 1×10-9-1×10-7 mol/L,the growth of Microcystis wesenbergii was promoted in low concentrations and inhibited in high concentrations,while the growth of Navicula was inhibited in the whole range and the inhibitory effect was more obvious along with the concentration increase.The adsorption experiments showed that the adsorption rate of Microcystis wesenbergii and Navicula on HgCl2 were in the range of 88.4%-98.8% and 87.1%-97.5%,respectively.Moverover,the adsorption rate and absorption amount of the two species gradually increased with the concentration increases.This demonstrated that both Microcystis wesenbergii and Navicula had strong adsorption effects on HgCl2,and algae adsorbing mercury from aqueous phase would be harmful to water environment due to their potential mercury accumulations.