回用景观水菌藻群落结构及环境响应

Community Structure and Environmental Response for Landscape Water with Reclaimed Water Reuse

浮游藻类和浮游细菌是水环境食物网的重要组成部分,然而,目前对于再生水回用景观水中浮游藻类及浮游细菌的群落结构特征及其对水质变化响应的研究较少。该项目分析了浮游细菌、藻类群落结构特征,并探究了浮游细菌及藻类对水质的响应关系。结果表明,再生水作为水源补给景观水可改善水体水质及营养状态,再生水回用湿地、河道水质分别满足地表水环境质量标准Ⅲ类、Ⅴ类标准,营养状态分别为中营养、轻度富营养化。再生水的回用可使浮游藻类的密度和生物量维持在较低水平,各采样点藻类密度在1.08×106~4.37×10^(6)L^(-1),生物量在0.82~4.82 mg/L,且回用后氮磷营养盐与蓝藻密度相关性较强,而与硅藻密度的相关性不明显。回用水体浮游细菌主要优势门为变形菌门、放线菌门、拟杆菌门、蓝细菌门;再生水回用降低了水体微生物多样性,浮游细菌多样性由高至低依次为藻江河西支、湿地公园、东风大沟;靠近回用水量最大的检测点位,其浮游细菌丰度与氮、磷营养盐相关关系并不显著,随着补水路径延长,微生物丰度与氮磷营养盐相关关系加强。

Phytoplankton and bacterioplankton are important components of the water environment food web.However,there are few studies on the community structure characteristics of phytoplankton and bacterioplankton and their response to water quality changes after reclaimed water reuse.This project analyzed the community structure characteristics of planktonic bacteria and algae,and explored the response relationship between planktonic bacteria and algae to water quality.The results showed that the reclaimed water as a water source to supply landscape water could improve the water quality and nutritional status.The reclaimed water reuse wetland and river water quality met the surface water environmental quality standards III and standards V,respectively,and the nutritional status were medium nutrition and mild eutrophication,respectively.The reuse of reclaimed water could maintain the density and biomass of phytoplankton at a low level.The algae density at each sampling point was from 1.08×10^(6)L^(-1)to 4.37×10^(6)L^(-1),and the biomass was from 0.82 mg/L to 4.82 mg/L.After reuse,the correlation between nitrogen and phosphorus nutrients and Cyanobacteria density was strong,but the correlation with diatom density was not obvious.The main dominant phyla of planktonic bacteria in reclaimed water were Proteobacteria,Actinobacteria,Bacteroidetes and Cyanobacteria.The reuse of reclaimed water reduced the microbial diversity of water body,and the diversity of planktonic bacteria from high to low was the west branch of Zaojiang River,Wetland Park and Dongfeng Dagou.Near the detection point with the largest amount of reclaimed water,the correlation between the abundance of planktonic bacteria and nitrogen and phosphorus nutrients was not significant.With the extension of the water replenishment path,the correlation between microbial abundance and nitrogen and phosphorus nutrients was strengthened.