Cu2+对栅藻和鱼腥藻增殖的影响

通过藻类增长潜力(AGP)实验,研究了铜离子浓度对2种淡水浮游藻类增殖的影响.结果显示,当Cu2 质量浓度为0.001～0.100 mg·L-1时,能促进斜生栅藻增殖; Cu2 质量浓度为1.000～100.000 mg·L-1时,对斜生栅藻产生不同程度的毒性效应.当Cu2 质量浓度为0.001～0.010 mg·L-1时,会促进鱼腥藻增殖; Cu2 质量浓度为0.100～100.000 mg·L-1时,会对鱼腥藻产生不同程度的毒性效应.当Cu2 浓度为0.001～0.100 mg·L-1时,斜生栅藻和鱼腥藻细胞经过2 d的调整期,从生理上适应了新环境并进入对数增长期; Cu2 浓度达到1.000 mg·L-1时则需经4 d的调整期才能进入对数增长期,到14 d时2种藻细胞的密度仍在增加.对栅藻和鱼腥藻细胞密度的平均比增长率比较显示,斜生栅藻对Cu2 毒性效应的耐受力大于鱼腥藻.结果表明,在淡水水体中,微量的Cu2 有利于浮游藻类增殖,能够增进水体的富营养程度; Cu2 浓度超过1.000 mg·L-1时对浮游藻类的繁殖与生长有抑制或毒害作用; 过量的Cu2 还可能会导致食物链的破坏与水源的污染.因此,在使用硫酸铜杀藻时应注意其用量与使用次数可能会对水体造成的影响.

Effects of Cu2+ on the cell multiplication of Scenedesmus and Anabaena at different concentrations

Copper, as one of microelements existing in the life of plants, is necessary for their growth to some extent. The present paper intends to introduce our study on the effect of copper molecule Cu2+ on the cell multiplication of two species of phytoplankton in fresh water through algal growth potential test. The experimental results of our study have shown that the speed of the cell growth and multiplication of Scenedesmus obiquus would increase when the concentrations of Cu2+ get from 0.001 to 0.100 mg/L. Cu2+, which is likely to promote eutrophication of water body to reach its optimal concentration. But, at the same time, it may also result in toxic effects to different degrees at the concentrations of Cu2+ from 1.000 to 100.000 mg/L. The experimental results also show that the optimum concentration of Cu2+ for cell growth and multiplication of Anabaena sp. gets to 0.0010.010 mg/L. The process can also aggravate eutrophication of water body. However, the cell multiplication of Anabaena sp. would be inhibited at the concentration of Cu2+ from 0.100 to 100.000 mg/L. The tolerance of Scenedesmus obiquus would be larger than that of Anabaena sp. Since copper sulfate is an efficient algaecide, optimal use of copper sulfate helps to inhibit the cell multiplication of phytoplankton. Moreover, iteration and excessive use of copper sulfate to kill the algae can be expected to cause accumulation of Cu2+ in the water body. However, when the concentration of Cu2+ is above 1.000 mg/L, it would induce secondary pollution and even infect aquatic ecosystem and safety of drinking water.