在洋河水库设置 6 个采样点, 对浮游植物进行了周年研究, 并在夏季进行了每周一次的加密采样, 以揭示水华期间藻类优势种演替规律.结果表明洋河水库全年共检测到浮游植物8门41属49种, 群落季节变化与温度密切相关.春季隐藻门的啮齿隐藻(Cryptomonas erosa)为优势,夏季初期表层水温在25℃以下时,绿藻门的波吉卵囊藻(Oocystis borgei)占主要优势;当表层水温升至25℃以上,微囊藻(Microcystisspp.)迅速取代其成为绝对优势.秋季硅藻门的克洛脆杆藻(Fragiaria crotomensis)和隐藻门的啮齿隐藻(C. erosa)为优势.空间分布上水库北部浅水区域隐藻和硅藻生物量普遍高于南部; 受东南风影响, 蓝藻生物量在西洋河口S2点位最大.CCA分析表明夏季水华主体微囊藻的生物量与氮浓度正相关, 螺旋鱼腥藻在夏季仅作为第二优势种短暂出现于西洋河口处, 其出现与否受到磷营养盐的限制.%The Yanghe Reservoir is an important drinking water source for Qinhuangdao City. In recent years, severe blooms of cyanobacteria in this reservoir have become a growing threat to the water safety. To study the temporal and spatial patterns of the phytoplankton growth in Yanghe Reservoir, we continuously collected water samples from six sites throughout one year with a higher sampling frequency during the summer. We identified 49 phytoplankton species that belonged to 41 genera and 8 phyla. The seasonal variation of community structure was closely related to the tem-perature.Cryptomonas erosa of Cryptophyta was the dominant species in the spring.Oocystis borgeiof Chlorophyta was the dominant species in the early summer when the temperature of surface water was below 25℃.Microcystis spp. of Cyanophyta later became dominant when the water temperature rose above 25℃.Fragiaria crotomensis of Bacil-lariophyta andC. erosa were the dominant species in the autumn. The total biomass of both Cryptophyta and Diatom in the north part of the reservoir was higher than that in the south part. Due to the impact of southeast wind, the biomass of cyanobacteria in the west river mouth (S2) was the highest. CCA analysis showed positive correlation between the bio-mass ofMicrocystis spp. and the nitrogen level.Anabaena spiroides was only found in west river mouth and was short-lived. The appearance ofAnabaena spiroides could depend on the phosphorus level.
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