以浮游植物评价达赉湖水质污染及营养水平

AN EVALUATION OF WATER POLLUTION AND EUTROPHICATION IN THE DALAIHU LAKE USING PHYTOPLAKTON COMMUNITIES

1987-1988年在30个样点,四季采样,对达赉湖的浮游植物进行了种类组成,生物量、种群数量、优势种、污染指示种、硅藻指数、综合指数等群落生态学的初步研究,应用后五项参数对达赉湖水质污染及营养水平进行了评价。达赉湖浮游植物年均值达54.7×10~6个/L(细胞数,或个体数为2.3×10~6个/L),硅藻指数为149.3,综合指数为5.6。群落组成中污染指示种占65%,春季以绿藻的十字藻、卵囊藻为优势种,其它3个季节均以蓝藻中的微囊藻、鱼腥藻、腔球藻占优势,表明达赉湖已受到中等程度污染,属于蓝、绿藻型富营养湖。

The seasanal changes in the ecological features of phytoplankton community including species composition,population size,dominant species,saprobic indicators,diversity index, diatom biotic index,comprehensive index ect,were preliminarily studied at 30 sampling sta- tions in the Dalaihu Lake,Manzhouli.By using population densities(individuals and cells per litre),dominant species,saprobic indicators,diatom biotic indices and compre hensive index as the important biological parameters,the trophic level and saprobic degree were eva- luated for both the whole and subareas of the lake.In the Dalaihu Lake,the annual mean density of phytoplankton reached 54.7×10~cells per litre or 2.3×10~6 individuals per litre. The diatom biotic index was 149.3,the comprehensive index was 5.6 and the saprobic indica- tors comprised 65% of the total species in the community.In Spring,the dominant species of planktonic algae were almost entirely composed of green algae,especially Crucigenia quadrata and Oocystis.In Summer,Autumn and Winter,the dominant species of planktonic algae were almost entirely composed of blue-green algae,especially Microcystis(M.aeruginosa and M. flos-aquae)and Anabaena(A.spiroides and A.flos-aquae). All these features indicate that the lake has suffered from moderate pollution and can be regarded as a blue-green and green algae-eutrophic lake.