达里湖水体营养状况探索性分析

Exploratory Analysis of Nutrient Condition in Dali Lake

根据2005年6、8、9、12月达里湖水质调查结果,选择10个影响湖泊营养状况的特征参数,包括pH、DO、CODMn、NH4+、NO3-、NO2-、PO43-、TN、TP和浮游植物生物量。应用探索性数据分析方法对该湖泊营养状况进行研究。主成分分析表明(主成分F1主要反映氮营养盐和有机质含量,主成分F2主要反映磷营养盐和酸碱度情况,主成分F3主要体现浮游植物生物量的特征):8月F1在河流入口附近较高,其高低受河流径流量及水源的影响,12月F1在鱼群聚集的中部和西南部较高,说明冬季生物活动是影响湖水氮营养盐和有机质含量的主要原因。主成分F2、F3在秋季最高,即秋季磷营养盐最高,浮游植物生物活动较强。F1与盐度和碱度之间有较好的线性关系,在一定程度上可根据盐碱度变化来预测主成分F1,即氮营养盐和有机质含量。TN、pH和浮游植物生物量等是控制达里湖营养状况时空变化的主要驱动因素。

Four cruises were carried out in Dali Lake in June, August, September and December 2005. 10 variables including pH,DO,CODMn,NH4^＋,NO3^-,NO2^-,PO4^3-,TN,TP and the biomass of phytoplankton were analyzed with exploratory data analysis. Three principal eomponents（Fs）are extracted with principal component analysis： N nutrients and CODMn for FI, pH value and P nutrients for F2 and the biomass of phytoplankton for F3. Influenced by groundwater runoff and resources, F1 neare four rives is higher than other stations in August. Influenced by fish swimming, F1 in center and southwest is higher than other stations in December. P nutrients and the biomass of phytoplankton are the highest in autumn. A good linear relationship between F1 and salinity and alkalinity exists so N nutrients and organic content are predicted to a good extend on the basis of a linear model in which salinity and alkalinity is the independent variable. TN, pH value and the biomass of phytoplankton are dominating factors in assessing the variation of Nutrient Status in the Dali Lake.