利用大型浮游动物控制浮游植物过量生长的研究

Studies on Control of Excessive Phytoplankton Growth by Macrozooplankton

本文通过受控生态系统试验研究了大型浮游动物对浮游植物的控制作用。试验结果表明，在适当的富营养条件下，通过合理的生物操纵，使得大型渴、平突船卵、等大型植食性浮游动物达到和维持足够的密度，浮游动物在夏秋季能够有效地控制浮游植物的过量生长，改善水质。

Several enclosure experiments,which combined various factors such as season , nutrient concentration , macrozooplankton species and density , were conduct-ed to examine the control effect of macrozooplankton on excessive growth of phyto-plankton At total P-concentrations between 039 and119mg/L,total N-concentrations between 1. 01 and 1. 78mg/L ,mega-herbivorous zooplankton such as Daphnia magna can effectively control the overgrowth of phytoplankton in summer and autumn(June-Oct. ),resulting in improving of the water quality. Community response such as chlorophyll a concentration can be depressed by macrozooplankton. At the population level ,not only the net growth rate of green al-gae speciessuch as Ankistrodesmus angustus Bern.,Pediastrum simplex(Mey)Lemm. ,Selenastrum minutum(Nag. ) Coll. and Scenedesmus ) can be reduced by Dmagna,but also that of diatoms species(such as Melosira )and blue-green algae species(eg. Merismopedia elegans A. Br.)can be decreased. Biomanipulation is regarded as an effective method to control excessive phyto-plankton growth;Introducing mega-herbivorous zooplankton into lakes and(or)re-ducing grazing pressure of fish or producing shelters are proposed o achieve suffi-cient density of macrozooplankton.