太湖梅梁湾水体中胶体对铜绿微囊藻生长的促进效应

The bioeffect of natural colloids on the growth of Microcystis aeruginosa in Lake Taihu, China

为探讨太湖水体中胶体对铜绿微囊藻生长的影响,在太湖藻型湖区梅梁湾采集水样,采用常规过滤与切向流超滤(CFF)相结合的方法,得到胶体浓缩液(1nm^1μm).分别将胶体浓缩液、灭菌的胶体浓缩液与纯水配制成体积百分比为5%、10%、25%的培养液,接种处于指数生长期的铜绿微囊藻.结果表明,添加天然胶体浓缩液或灭菌胶体浓缩液可以促进铜绿微囊藻的生长,灭菌胶体对铜绿微囊藻生长的促进作用更显著.胶体促进铜绿微囊藻生长的主要原因是胶体态有机磷促进了铜绿微囊藻对溶解性无机磷的摄取,胶体所吸附的营养盐的补充是另一个有利因素.此外,胶体作为微量元素载体也是胶体促进铜绿微囊藻生长的原因之一.

To study the effect of natural colloids on the growth ofMicrocystis aeruginosa, water samples were collected from Meiliang Bay in Tahu Lake. Colloid concentrates were obtained by employing a cross-flow filtration system to ultrafilter the pre-filtrated（by 1μm membrane） water samples, with a 1 kDa membrane. Natural and sterilized colloid concentrates together with pure water were mixed in the ratios of 5%, 10%, 25%, then inoculated with Microcystis aeruginosa and cultivated in exponential phase. The added of natural colloids and sterilized colloids could stimulate the growth ofMicrocystis aeruginosa, and the stimulation of sterilized colloids on Microcystis aeruginosa was greater than natural colloids. The added colloidal organic phosphorus accelerating the absorption of dissolvable inorganic phosphorus was the main reason of stimulating effect, and the supplement of nutrient adsorbed on colloid was a another favorable factor. Besides, colloid being the carrier of trace elements also was a reason of stimulating effect of colloid on Microcystis aeruginosa.