洞庭湖湿地系统氮磷时空分布特征及环境效应

Spatial-Temporal Distribution Characteristics and Environmental Effects of N and P in Wetland System of Dongting Lake

湖泊水体中氮磷超标是引起富营养化问题的重要因素,研究湿地系统地下水中氮磷的时空分布特征对于解决湖泊富营养化问题具有重要意义。本文以西洞庭湿地为研究对象,在澧水和沅水入湖口湿地进行了为期一年的地表水和地下水环境监测,探讨了西洞庭湿地演替带氮磷时空分布特征及其环境效应。研究结果表明:西洞庭湿地演替带水体中不同形态氮和磷的时空分布均呈现出非均一性特点,以农业为主的澧水演替带地下水中氮磷浓度普遍高于非农业区的沅水演替带。氮磷在水体中相伴而生,且水体中磷酸盐浓度与三氮浓度( NO-3、NO-2和NH+4-N)存在显著的线性正相关关系。在不同季节演替带存在地表水和地下水的交替补给作用,地水体中氮磷浓度超标会影响地下水环境质量,甚至危害饮用水安全。

Excessive nitrogen (N) and phosphorus (P) are the key elements to cause the eutrophication problem in the lake. Therefore studying the spatial and temporal distribution characteristics of nitrogen and phosphorus in the groundwater of wetland system has the vital significance to solve the eutrophication problem. In this paper, the West Dongting Lake was taken as the research object, and the surface water and groundwater environmental monitoring were made at two repre-sentative reaches of Dongting Lake, within the riparian zones of the Li River and Yuan River. Ulti-mately, the spatial and temporal distribution characteristics of nitrogen and phosphorus and its environmental effects in the west Dongting wetland succession zones were studied. The research results showed that the spatial-temporal distribution of N and P in Dongting Lake is heterogeneous, with the concentrations of nitrogen and phosphorus in agricultural Li succession zones higher than that of non-agricultural Yuan succession zones. The existence of nitrogen and phosphorus is accompanied in water body, and the concentrations of  significantly correlated with those of N species ( ,  and  ).There exists the alternate replenishment effect of surface water and groundwater in succession with the season. The over-standard concentrations of nitrogen and phosphorus have some contaminated effect on groundwater quality, further endangering the safety of drinking water.