不同营养水平调水对贡湖湾湖区水质及浮游藻类影响的模拟研究

Simulated Study of Water Diversion with Different Trophic Levels Effects on the Water Quality and Phytoplankton Community in Gonghu Bay

为探究“引江济太”工程调水给受水湖区水体带来的生态效应,采用水生微宇宙模型进行为期11 d的室内模拟实验,以太湖贡湖湾湖区为受水水体,引入3组设定好的不同营养盐水平(贫营养水平O、中营养水平M、富营养水平E)的望虞河河水,研究在不同营养盐水平调水影响下,受水水体水生态环境的动态响应过程。结果表明:整个实验过程中,中营养和贫营养调水组的水体TN、NO_(3)^(-)-N、NH4_(+)-N、TP、SRP、TOC含量下降明显,富营养调水组影响效果较中营养和贫营养调水组差;调水提高了受水水体生态系统的多样性和均匀度水平,硅藻等非蓝藻细胞密度增加,蓝藻细胞生长受到竞争胁迫,中营养和贫营养调水的影响作用效果好于富营养水平。RDA分析结果表明,受水水体的pH、DO、SiO_(3)^(2-)-Si、TDS、NO_(3)^(-)-N、SRP是本实验水体影响藻类群落结构的主要环境驱动因子。

To explore the ecological effects of“water diversion project from Yangtze River to Taihu Lake”on the water bodies in the receiving lake area,the simulated indoor experiment was constructed using an aquatic microcosm model in a period of 11 days.The Gonghu Bay area of Taihu Lake was used as the receiving water body,and three groups of Wangyu River water with different nutrient levels O,M,E(Oligotrophic group,Mesotrophic group,Eutrophic group)were introduced to study the dynamic response process of the water ecological environment of the receiving water body under the influence of water diversion at different nutrient levels.The purpose is to provide a basis for the rational formulation of water diversion scheduling plans and the optimization of the scheduling effect of the“water diversion project from Yangtze River to Taihu Lake”.The results showed that:during the experiment,total nitrogen(TN),nitrate nitrogen(NO_(3)^(-)-N),ammonia nitrogen(NH_(4)^(+)-N),total phosphorus(TP),soluble reactive phosphate(SRP)and total organic carbon(TOC)in oligotrophic group and mesotrophic group decreased significantly.The effect of eutrophic water diversion group was worse than that of oligotrophic group and mesotrophic group.Water diversion increased the Shannon-Wiener diversity and Pielou’s evenness index in this water ecosystem.Density of diatoms and other non-cyanobacteria increased.Meanwhile,the growth of cyanobacteria was under competitive stress.The effect of oligotrophic group and mesotrophic group was better than that of eutrophic group.Simultaneously,the results of redundancy analysis showed that:pH,DO,SiO_(3)^(2-)-Si,TDS,NO_(3)^(-)-N,and SRP of the receiving water body were the main environmental factors influencing the distribution of phytoplankton community in this experiment.