潜流湿地净化技术对池塘循环水养殖系统浮游植物群落变化的影响

The study about the change of phytoplankton community based on undercurrent wetland purification technics water circulation of farming systems

构建"潜流湿地+生态池"的湿地生态系统,并以纯生态池净化系统作为对照区,对实验区与对照区内的浮游植物群落结构进行分析,评价该系统的运行效果。结果表明:循环水养殖工程正式运行后,体系中的养殖池塘浮游植物种类数由多到少的顺序为养殖池塘(对照区)>养殖池塘(实验区)>外河。养殖池塘的浮游植物密度、生物量及生物多样性指数高于外河。经过3级净化后水体浮游植物种类由高到低的顺序为外河>净化系统(对照区)>净化系统(实验区),密度与生物量迅速下降。生物多样性指数也低于外河,但随着运行时间的增加,其生物多样性指数持续增加。同时,实验区浮游植物多样性均小于对照区,水体营养盐去除更彻底,水质净化效率更高。

A wetland ecological system composing of subsurface flow wetland and biological purification process was constructed and a purification system by single biological treatment was used as contrast area in this study. In order to assess the operation effects of the wetland ecological system, the differences in yields, aquaculture benefits and phytoplankton community structures between test area and control area were comparatively analyzed. The main results were summarized as follows： After discharged water-recirculating aquaculture engineering was practiced, the highest number of phytoplankton species occurred in fish farming ponds in control area,followed by those in test area, and by outside river,in descending order. The densities and biomass of phytoplankton species, and species diversity index in farming ponds were higher than those in outside river. By 3 sequential purification procedures, the outside river had the highest number of phytoplankton species, followed by control area, and the last one was test area respectively. The densities and biomass decreased rapidly, and the species diversity index was also lower than that in the outside river. Subsequently,the species diversity index continuously increased with the running time of the system. In addition, the phytoplankton species diversity in test area was lower than that in control area, nutrient salts were removed more thoroughly in test area, indicating higher water-purifying efficiency.