武汉东湖夏冬两季浮游动物物种多样性及群落结构研究

SPECIES DIVERSITY AND COMMUNITY STRUCTURE OF ZOOPLANKTON IN SUMMER AND WINTER IN THE EAST LAKE, WUHAN

  • 摘要: 2018年7月、8月、12月及2019年1月, 对武汉东湖沿岸带的浮游动物群落分夏冬两季进行了调查研究。共鉴定出浮游动物35属50种, 其中轮虫22属37种、枝角类10属10种、桡足类3属3种。夏季优势物种为跨立小剑水蚤(Microcyclops varicans)、裂足臂尾轮虫(Brachionus diversicornis)和微型裸腹溞(Moina micrura); 冬季优势物种为长肢多肢轮虫(Polyarthra dolichoptera)、疣毛轮虫(Synchaeta spp.)、角突臂尾轮虫(Brachionus angularis)和犀轮虫(Rhinoglena sp.)。将观察到的浮游动物进行了图像信息采集, 并确定了部分物种SSU rRNA序列, 为淡水浮游动物的研究提供了参考资料。参考武汉东湖浮游动物研究的历史文献数据, 东湖数十年来浮游动物物种数逐渐下降, 轮虫优势物种由寡污型转为β-中污型甚至α-中污型。夏冬两季东湖浮游动物群落结构具有明显差异, 夏季轮虫平均密度(56.2 ind./L)和生物量(0.22 mg/L)低于冬季(476.3 ind./L、0.44 mg/L), 而甲壳类密度(137.8 ind./L)和生物量(2.88 mg/L)高于冬季(53.1 ind./L、1.12 mg/L)。夏季浮游动物群落Margalef丰富度指数、Shannon-Wiener多样性指数和Simpson多样性指数均高于冬季, 夏冬两季Pielou均匀度指数差异不大, 水质评价表明东湖夏季(中污染)优于冬季(重污染)。夏冬两季温度、溶解氧、pH、盐度和ORP五种环境因子均存在极显著差异, RDA分析表明, 其中温度对浮游动物群落结构的影响最大。

     

    Abstract: This study investigated the zooplankton community in the East Lake in July, August, December 2018 and January 2019 and identified a total of 50 species of the zooplankton belonged to 35 genera, including 37 Rotifera belonged to 22 genera, 10 Cladocera belonged to 10 genera, and 3 copepoda belonged to 2 genera. The dominant species were Microcyclops varicans, Brachionus diversicornis, and Moina micrura in summer and Polyarthra dolichoptera, Synchaeta spp., Brachionus angularis, and Rhinoglena sp. in winter. The image information of all observed zooplankton was collected, and the SSU rRNA gene sequences of dominant species were determined to provide reference data for the identification of freshwater zooplankton. According to the historical data about zooplankton in Wuhan East Lake, the number of zooplankton species in the East Lake has decreased gradually in the past few decades, and the dominant species of rotifers have changed from oligosaprophyte to beta-mesosaprobity or even alpha-mesosaprobity. The zooplankton community structure in East Lake was significantly different in summer and winter. The rotifer density (56.2 ind./L) and biomass (0.2188 mg/L) in summer were lower than those in winter (476.3 ind./L, 0.4415 mg/L), while the crustacean density (137.8 ind./L) and biomass (2.8831 mg/L) were higher than those in winter (53.1 ind./L, 1.1187 mg/L). The Margalef richness index, Shannon-Wiener diversity index and Simpson diversity index of the zooplankton community in summer were higher than those in winter. The Pielou evenness index is not different between summer and winter. The water quality evaluation showed that the water quality in summer (moderately polluted) was better than that in winter (heavily polluted). There were significant differences in temperature, dissolved oxygen, pH, salinity and ORP between summer and winter. Redundancy Analysis (RDA) indicated that temperature had the greatest influence on zooplankton community structure.

     

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