【摘要】 2003—2004年的调研结果显示,北京城市河湖(长河水系)总氮平均含量为1.667mg/L,总磷平均含量为0.144mg/L,浮游藻类平均细胞密度为41150×104/L,其中蓝藻占90.0%。浮游藻类的群落结构为蓝藻(Cyanophyta)-绿藻(Chlorophyta)型,河湖水体中营养盐与初级生产力的关系为浮游藻类响应型,连续两年发生以微囊藻(Microcystis)占优势的蓝藻水华。河湖水体5项指标(SD、TP、TN、CODMn、Chla)的TSIM值在57～87间,水体已达到富营养或重富营养程度。其主要原因是:1)营养盐和有机物的污染;2)北京市淡水资源紧缺,补给城市河湖水量少;3)在河湖水系治理中,底部硬化,两侧(或周围)衬砌,破坏了水体的自然生态系统,使其自净能力大大降低。更多还原

【Abstract】 The urban river and lakes in Beijing have important action on supplying water, controlling flood and city ecosystem. It was the window to reveal economic development and city construction of capital. Long River passed Beijing town and has very representative character. The research results to Long River system in 2003—2004 years indicates that total nitrogen was 1.667 mg/L, total phosphorus was 0.144 mg/L and COD_ Mn was 5.98 mg/L. The community structure of phytoplankton was of Cyanophyta-Chlorophyta type, with an average cell density of 41 150×104/L. The blue-green algae made up 90.0 per cent of the total cell density and Chlorophyta was 7.6%, Bacillariophyta was 1.4%.The nutrition characteristic belongs to responding type of phytoplankton. TSI_M of five targets (TN, TP, COD_ Mn, SD, Chla) were form 54 to 87 which showed that nutritive condition of Long River was from eutrophication to hypertrophy and water bloom of blue-green algae occurred frequently in summer and autumn. The principal factors to cause eutrophication of the urban river and lakes in Beijing were (1) the pollution of nutritive salts and organic matter. (2) the water quantity to supplying urban river and lakes was little. (3) the ecological system of river and lakes have destroyed and self-purification capacity of water body were a marked drop. The proposal to protect valley ecological environment and to harness pollution in converging water region were put forward in the paper.更多还原