基于模拟数据分析长江调水对棘洪滩水库的影响

Assessment of Effects of Yangtze River Water Transfer on the Jihongtan Reservoir Based on Simulated Data

目前南水北调东线调水工程水源复杂多变,显著影响了受水水体的水质与浮游藻类。为量化与评估这一影响,本研究在调水周期内采集不同季节的供水(长江水)、受水(棘洪滩水库水)水样,同时开展室内藻类生长潜力试验,比较分析了不同比例的供、受水体混合处理后的理化因子、浮游藻类细胞密度与群落结构的变化情况。结果显示,春、秋季长江水的引入一定程度上削弱了棘洪滩水库的营养负荷;pH在季节间均表现为下降的趋势;秋季长江水的引入导致棘洪滩水体浮游藻类密度峰值显著增加(P<0.05),而在春季,仅当长江调水比例高于40%时,藻类密度峰值才随调水量的增加而显著增大(P<0.05)。群落结构方面,春、秋季长江与棘洪滩水体浮的游藻类均以蓝藻为主要优势,不同的是,春季以色球藻属(Chroococcus)的种类占主要优势,秋季则以假鱼腥藻属(Pseudanabaena)、尖头藻属(Raphidiopsis)与细鞘丝藻属(Leptolyngbya)的种类为优势。随长江水引入比例的增加,春季调水进一步增加了色球藻属的优势度;秋季调水则削弱了尖头藻属优势度同时增加了假鱼腥藻属的优势度。综合表明,不同季节长江调水对棘洪滩水库的浮游藻类生长影响存在差异,浮游藻类群落结构显著受到供水水体与季节的综合影响。

Currently,the water sources of the east route of the South-to-North Water Diversion Project are complex and variable,significantly affecting the water quality and phytoplankton of the receiving water bodies.To quantify and evaluate this impact,samples of the suppling water(Yangtze River)and receiving water(Jihongtan reservoir)were collected in different seasons during the water transfer cycle in this study.At the same time,the algae growth potential(AGP)test was conducted in the laboratory to compare and analyze the changes in physical and chemical factors,phytoplanktonic cell density and community structure after mixing of suppling and receiving water bodies in different proportions.The results indicated that the introduction of Yangtze River water in spring and autumn had reduced the nutrient load of Jihongtan reservoir to a certain extent.pH showed a downward trend across seasons.The introduction of Yangtze River water during autumn resulted in a significant increase(P<0.05)in the peak of phytoplanktonic density in the Jihongtan reservoir water.While in spring,only when the proportion of water diversion from the Yangtze River was higher than 40%,the peak of algal density increased significantly(P<0.05)with the increase in water diversion.Regarding community structure,the species of Cyanobacteria dominated both the Yangtze River and Jihongtan water bodies in spring and autumn.The difference was that in spring,species of the genus Chroococcus were dominant,while in autumn,species of the genera Pseudanabaena,Raphidiopsis and Leptolyngbya were dominant.With the increase in the proportion of Yangtze River water,the dominance of Chroococcus sp.was further increased in spring,while water transfer in autumn weakened the dominance of Raphidiopsis sp.but increased the dominance of Pseudanabaena sp..The comprehensive results showed that there were differences in the impact of Yangtze River water diversion on the growth of phytoplankton in Jihongtan reservoir in different seasons,and the phytoplanktonic community structure was significantly affected by the combined effects of suppling water and seasons.