北京四海浮游藻类叶绿素含量与水体营养水平的研究

1987年1-12月对北京四海叶绿素含量进行了逐月测定,结果表明,各海叶绿素含量明显不同。四海叶绿素含量年均变化在0.0075-0.0259mg/L之间,其中以前海为最低,北海为最高。叶绿素含量有明显的季节变化,冬季最低,夏、秋季最高。四海叶绿素a的含量随水温、色度、悬浮物、BOD5、COD、总磷、总氮、藻类数量的增加而增加,随水体透明度的上升而下降。用叶绿素含量作为指标对四海富营养程度评价结果为:西海、后海、前海为中略偏富营养,北海为富营养水体。  

A STUDY ON THE ALGAL CHLOROPHYLL CONTENTS AND TROPHIC LEVEL IN FOUR CONNECTED LAKES IN BEIJING

Measurements were made on the chlorophyll contents and trophic states in six connected small lakes in the central area of Beijing city, during January-December 1987. The results on the northern four lakes are presented in this paper. 1. Chlorophyll contents showed marked differences among the lakes, and were much lower in the northern three lakes than in the southern lake, Lake Beihai. 2. In Lake Beihai, chlorophyll contents showed marked seasonal variations, being highst in summer and lowest in winter. The same trend was observed, though to a less extent, in the other three lakes. The results indicated that the trophic level was much higher in Lake Beihai than in the other three lakes. 3. Regression analysis showed that the content of chlorophyll a increase with increased water temperature, water colour, total phosphoius and algal density, and decreased transparency. 4. Evaluation of water quality based on chlorophyll a content suggested that the northern three lakes were mesoeutrophic, and Lake Beihai was eutrophic. The results agreed well with those from a conprehensive evaluation based on several biological, physical and chemical variables. Thus the chlorophyll a content is a satisfactory biological index for the evaluation of trophic level of lakes.