天目湖水体与沉积物中营养盐时空分布及成因

Spatial-temporal Distribution of Nutrients and Its Causation in Tianmu Lake,China

采用现场监测及实验室分析方法,2006年对天目湖水体和沉积物营养盐等进行了调查。结果发现,天目湖水体中营养盐浓度影响最大的是上游流域输入,冬季天目湖上游输入的颗粒物是导致水体营养盐尤其是TN水平升高的主要因素;而在夏季,水体中营养盐以溶解态为主,天目湖的营养类型是磷限制。表层沉积物营养盐含量最高的点位是下游靠近大坝取水口附近,表层沉积物N、P含量明显高于其下各层,尤其对于营养盐含量较高的点位。研究表明,作为一个兼顾饮用水源地和旅游功能的水库,上游区流域综合保护、水库渔业调控及旅游活动的进一步规范是控制天目湖富营养化的关键。

The concentrations of nutrients in water and sediment, such as nitrogen, phosphorus and organic matter, were investigated during 2006 in Tianmu Lake, a reservoir which was the main drink water resource and recreation place in Liyang City, Jiangsu Province, China. Up- stream input had strong influence on nutrients concentrations in the reservoir. On the other hand, contributions from the tourism and real-es- tate construction around the reservoir were also very significant. In winter, the particulate nutrients from upstream were the main sources of the nutrients in the lake. However, most of the N and P in lake were presented as dissolved form in summer, indicating the strong influence from fishery and tourism. The annual mean value of nitrogen/phosphorus ratio in water was 33, suggested that the eutrophication of the lake was phosphorus limited. Nutrients contents in top layer sediments were significantly higher than those in deeper layers, especially in the out- let area. The research suggested that environment protection in the catchments, fishery adjust, as well as tourism control were very important for the eutrophication control of Tianmu Lake.