武汉东湖浮游植物水华的多元分析

MULTIVARIATE ANALYSIS OF PLANKTONIC BLOOMS IN LAKE DONGHU, WUHAN

应用多元分析中的fuzzy聚类分析、Fisher判别分析和逐步回归分析,对武汉东湖1983至1985年浮游植物水华进行一系列分析处理,得到其Ⅰ、Ⅱ两站的水华判别函数,分析了判断水华形成的主要指标:Ⅰ站为初级生产量和氨氮浓度,Ⅱ站为温度、硝酸盐浓度、叶绿素a浓度和COD,此外,本文还就Ⅰ、Ⅱ两站浮游植物的两个因子(chl a和初级生产量)分别对不同形态的营养元(氨氮、亚硝酸盐、硝酸盐、总氮、磷酸盐、总磷和硅酸盐)进行了回归分析;结果指出,现在东湖浮游植物不是以磷为限制因子而是氮限制。

By using multivariate analysis for 14 parameters obtainded in 1983 to 1985 at the two sampiing stations (Ⅰ, Ⅱ) in Lake Donghu, Wuhan, the relationships between water-blooms and relevant ecological parameters were analysed, and the discriminant function of water-blooms at each station was yielded. The principal factor in relation to water-blooms are gross primary production and concentration of ammonia-N at station Ⅰ, and water temperature, nitrate con centration, chlorophyll a and COD at station Ⅱ. Regression analysis of phytoplankton indexes (chl a and pG) against several nutrients (ammonia-N, nitrite, nitrate, total-N, phosphate, to tal-P and silicate) demenstrate that the principal limiting factor for phytoplankton in Lake Donghu at present is nitrogen instead of phosphorus.