MULTIVARIATE ANALYSIS OF PLANKTONIC BLOOMS IN LAKE DONGHU, WUHAN

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.