南亚热带湖泊-星湖后生浮游动物群落特征研究

CHARACTERISTICS OF THE METAZOAN ZOOPLANKTON COMMUNITY IN XINGHU LAKE-A SOUTHERN SUB2TROPICAL LAKE

  • 摘要: 星湖位于广东省境内,是一个南亚热带浅水自然湖泊,由5个子湖组成,是典型的富营养化湖泊。为了解这一典型南亚热带富营养湖泊的后生浮游动物群落特征,于2002年对该湖的轮虫和浮游甲壳动物进行了研究。星湖的后生浮游动物基本上为广温种类,兼具一些嗜暖种。轮虫在种类数、数量和生物量上均占优势,其优势种为臂尾轮虫。在4个子湖中,波海湖的臂尾轮虫数量最高,与该子湖营养水平较高相对应。桡足类为第二优势类群,在数量上以无节幼体和桡足幼体为主,并且在7、8月份数量较高,优势种为温中剑水蚤和台湾温剑水蚤;枝角类优势种则是长额象鼻溞和颈沟基合溞。两类浮游甲壳动物成体的数量均比较低。与20世纪90年代相比,星湖后生浮游动物的数量和生物量均下降,两类甲壳动物均向小型种类演替。和我国北亚热带的富营养化湖泊相比,星湖后生浮游动物的数量和生物量都明显偏低,这可能反映了南亚热带浅水湖泊的特征。

     

    Abstract: Xinghu Lake is a typical shallow lake located in the southern sub2tropical region of Guangdong Province, South China, and it comprises five basins, namely, Bohai, Li, Zhongxin, Xiannü and Qinglian1It has been eutrophic since the late 1990’s1In order to understand the response of zooplankton community structure to eutrophication, metazoan zooplankton, including rotifers, cladocerans and copepods, were investigated in 2002 in the lake177 taxa of metazoan zooplankton were observed1The metazoan zooplankton species were mainly composed of eurythermal ones and only a few thermophil ones were also found1The abundance of zooplankton ranged from 7152 ind1/L to 1505 ind1/L, and it was the highest in Bohai, namely 814199 ind1/L on aver2 age1Among three groups, rotifers dominated in the number of species, abundance and biomass, and the dominant genus was Brachionus1The abundance of rotifers in Bohai, reached 360124 ind1/L, was the highest in the four investigated basins, corre2 sponding to its highest trophic status1Copepods were the second dominant group1Nauplii and copepodites contributed more than 85% to the total abundance of copepods, and they had higher abundance in July and August1The dominant species were Mesocyclops thermocyclopoides and Thermocyclops taihokuensis1 Cladocerans were mainly composed of Bosmina longirostris and Bosminopsis deitersi1 The very low abundance of cladocerans and adults of copepods in the four basins was probably related to fish predation1In comparison with the data about zooplankton in the lake in 1996-1997, the abundance and biomass of metazoan zooplankton decreased significantly in 2002, and the crustacean changed into smaller2sized species1In contrast to the other lakes with similar trophic status in the northern sub2tropical region of China, the abundance and biomass of rotifers, cladocerans and copepods were much lower in this southern sub2tropical shallow lake1Although the lake is located far from the Equator, its meta2 zoan zooplankton community is similar to those typical lakes near the Equator1

     

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