太湖流域源头溪流富营养化特征及影响因素

为研究太湖流域源头溪流水体富营养化特征及其影响因素,以2013年南苕溪主要河流四季水质数据为基础,探讨了环境因子与藻类的变化规律及其相互作用机制.结果表明：水环境中TN、TP、Chl-a平均含量分别为2.81 mg/L、0.11 mg/L、16.70 mg/L,氮素含量较高.自上游源头林区至下游城镇区,营养盐、Chl-a含量和营养状态都明显上升,说明流域富营养化状况受人为活动影响显著.与上游源头林区相比,其他区域藻类群落对Chl-a贡献比例的变化主要表现为硅藻比例的下降以及蓝藻和绿藻比例的上升.相关性分析表明,水温、浊度、电导率、流速以及营养盐中的TP和PO34--P与Chl-a含量显著相关.水温是影响蓝绿藻生长的重要因素,硅藻的数量与浊度和营养盐含量存在明显正相关,水体流动对藻类的生长具有抑制作用.

Characteristics of Eutrophication and Its Response Factors in Headwater Streams of Taihu Lake

In order to explore the relationships between eutrophication and environmental factors in headwater streams of Taihu Lake.Variations of environmental factors and algae as well as their interaction mechanisms were studied.The results indicated that the concentrations of total nitrogen （TN）,total phosphrous （TP） and Chl-a were 2.81 mg/L,0.11 mg/L,16.70 mg/L,respectively.Moreover,nutrient content,Chl-a and trophic state followed a space pattern,increased significantly from upstream to downstream.The proportion of diatom decreased with the increasing proportions of cyanobacteria and chlorophyta from upstream to downstream.Although water temperature,turbidity,conductivity,flow velocity,TP and PO34--P had significant correlations with algal biomass,the relationships between algal community and environmental factors were different.Water temperature was the main factor of promoting growth of cyanobacteria and chlorophyta ; diatom was related to nutrients and the turbidity; surface flow inhibited the phytoplankton growth.