基于时空分布的阳澄湖营养化进程及其趋势

A spatiotemporal eutrophication process and the changing trends in Yangcheng Lake

目的:研究阳澄湖营养状态变化.方法:基于2002-2012年的水质监测数据,以生态学指标(叶绿素a)、营养盐指标(总氮、总磷)及理化指标(高锰酸盐指数、透明度)作为评价因子,运用综合营养状态指数法和ArcGIS反距离权重插值法对时空分布下的阳澄湖营养程度进行了定量判别,并用spearman秩相关系数检验法对其变化趋势进行分析.结果:阳澄湖总体呈轻度富营养状态,TLI值西湖>中湖>东湖.年际间各湖区TLI值波动平稳,最大TLI值为60.7,出现在2008年的西湖.结论:整体变化大致可以分为直线上升、缓慢波动和水质转好3个阶段;空间上由西湖向东湖递减,南侧水质略优于北侧;湖泊营养状况总体得到好转,SD呈显著上升趋势,TN、TP和COD_(Mn)呈高度显著下降趋势,TLI呈显著下降趋势.

Aim：Study on changes in the nutritional status of Yangcheng Lake,phased on water quali-ty monitoring data from.Methods：The eutrophication levels of Yangcheng Lake were quantitatively dis-criminated by the Comprehensive Trophic State Index method and inverse distance weighted interpolation method of ArcGIS,and Spearman＇s rank correlation coefficient test was applied to analyze change trend, in which series of the environmental factors were considered including the ecological indicator of Chl-a, the nutrient indicator of TN and TP,the physical and chemical indicator of SD and CODMn .Results：O-verall Yangcheng Lake was in mild eutrophication level,TLI value of West Lake is the largest,East Lake is the smallest.The fluctuation of TLI value in each lake area was the same,the maximum value ap-peared in West Lake in 2008,and the TLI value was 60.7.Conclusion：The whole change can be divid-ed into three stages：straight line,slow wave and water quality improvement.On the space,water quality is better from West Lake to East Lake and from.The trophic state of the lake has been improved in recent years.The SD shows a significant upward trend,and the TP,CODMn and TN are highly decreased,and＆amp;nbsp;TLI decreased significantly.