瓯江干流丽水段浮游生物群落特征的时空变化研究

Temporal and Spatial Variations of Plankton Community Structure Characteristics in Lishui District of Oujiang River Main Stream Area

根据2009年春(3月)、夏(6月)、秋(9月)、冬(12月)四个季节瓯江干流丽水段(28°16′47.03″-28°24′42.66″N、119°42′31.41″-119°57′13.03″E)的浮游生物调查资料,对瓯江干流丽水段浮游植物和浮游动物群落的种类、数量、多样性指数等群落结构特征的时空变化进行了分析。结果表明:瓯江干流丽水段共发现浮游植物55种,隶属于8门55种(属),调查区域内浮游植物以绿藻和硅藻为主,浮游植物细胞丰度介于0.2×104~4.88×104 cells·L^(-1)之间,平均为1.16×104 cells·L^(-1),生物量介于0.005 1~0.104 mg·L^(-1)之间,平均为0.043 mg·L^(-1),浮游植物细胞丰度和生物量最高点出现在夏季的9#采样点,四季变化趋势为夏季(1.63×104 cells·L^(-1)和0.078 mg·L^(-1))>春季(1.09×104 cells·L^(-1)和0.034 mg·L^(-1))>秋季(1.05×104 cells·L^(-1)和0.027 mg·L^(-1))>冬季(0.92×104 cells·L^(-1)和0.023 mg·L^(-1));生物多样性指数中Margalef指数(D)介于2.20~3.71之间,ShannonWiener指数(H′)介于1.39~2.52之间,Pielou均匀度指数(J′)介于0.27~0.46之间,Simpson指数(d)介于0.68~0.80之间,其中H′、J′和d最高值均出现春季,而D最高值均出现夏季。浮游动物共发现4大类22种,优势种为砂壳虫;浮游动物细胞丰度介于8.25~246 ind·L^(-1)之间,平均密度为73.53 ind·L^(-1),生物量介于0.01~3.10 mg·L^(-1)之间,平均为0.49 mg·L^(-1);浮游动植物细胞丰度和生物量最高值出现在夏季的9#,细胞丰度四季变化趋势为夏季(19.26 ind·L^(-1))>秋季(5.54 ind·L^(-1))>春季(3.14 ind·L^(-1))>冬季(0.58 ind·L^(-1)),生物量四季变化趋势为冬季(0.98 mg·L^(-1))>夏季(0.81 mg·L^(-1))>秋季(0.13 mg·L^(-1))>春季(0.05 mg·L^(-1));生物多样性指数中Margalef指数(D)介于2.20~6.26之间,Shannon-Wiener指数(H′)介于1.40~1.92之间,Pielou均匀度指数(J′)介于0.29~0.38之间,Simpson指数(d)介于0.61~0.83之间,其中四种多样性指数的最高值均出现春季。浮游动植物数量及群落多样性指数显示,瓯江干流丽水段水质已受到中度污染,处于贫-中营养化状态。

Studies on the spatio-temporal variations of plankton species ,quantity, diversity index and communities structure are conducted, based on data from plankton resource surveys in four seasons of 2009 in Lishui district of Oujiang River main stream area. The result showed that 55 species of phytoplankton were identified, which belongs to 8 orders and 55 genus. The dominant species were Bacillariophyceae and Chlorophyceae. The cell abundance of phytoplankton ranged from 0.2×10^4 cell ·L-1 to 4.88×10^4 cell·L-1, averaging 1.16×10^4 cell ·L-1. The biomass ranged from 0.005 1 mg·L-1 to 0.104 mg·L-1, averaging 0.043 mg·L-1. The highest cell abundance and biomass were in the ninth sampling site in summer. Seasonal change of cell abundance and biomass of the phytoplankton was the maximum appeared in summer （1.63×10^4 cells·L-1 and 0.078 mg·L-1）, followed by spring （1.09×10^4 cells·L-1 and 0.034 mg·L-1）, autumn （1.05×10^4 cells·L-1 and 0.027 mg· L-1） and winter （0.92×10^4 cells·L-1 and 0.023 mg·L-1）. The range of Margalef index（D）, Shannon-Wiener index （H＇）, Pielou index （J＇） and Simpson index （d） were from 2.20 to 3.71, from 1.39 to 2.52, from 0.27 to 0.46 and from 0.68 to 0.80 respectively, of which the maximum of H＇, J＇ and d appeared in spring, while maximum of D appeared in summer. 22 kinds of zooplanktons were identified, and the dominant species was Difflugia.. The cell abundance of zooplankton ranged from 8.25 ind·L-1 to 246 ind· L-1, averaging 75.53 ind·L-1. The biomass ranged from 0.01 mg·L-1 to 3.10 mg·L-1, averaging 0.49 mg·L-1. The highest cell abundance and biomass were in the ninth sampling site. Seasonal change of cell abundance and biomass of the zooplankton was the maximum appeared in summer （19.26 ind·L-1）, followed by autumn （5.54 ind·L-L）, spring （3.14ind·L-t） and winter （0.58 ind·L-1）, while seasonal change of the biomass was the maximum appeared in winter （0.98 mg·L-1）, fol- lowed by summer （0.81 mg＇L-I）, autumn （0.13 mg·L-1） and spring （0.05 mg·L-1）. The changing range of Mar- galef index（D）, Shannon-Wiener index（H＇）, Pielou index （J＇） and Simpson index （d） were from 2.20 to 6.26, from 1.40 to 1.92, from 0.29 to 0.38 and from 0.61 to 0.83 respectively, of which the maximum of D, H＇, J＇ and d appeared in spring. Based on evaluation results of plankton community structure and diversity index, the water quality of Lishui district of Oujiang River main stream area was oligo-mesotrophic.