杭州湾滩涂湿地浮游生物群落特征及与环境因子的关系

Characteristics of plankton community and their relationships with environmental factors in mudflat wetland of Hangzhou Bay,East China

为探明杭州湾滩涂湿地浮游生物群落特征及其与环境因子的关系,于2010年4月—2011年1月,逐季对杭州湾南岸滩涂湿地5个断面(S1—S3为排水区,S4—S5为非排水区)的高潮位和中潮位分别进行浮游生物群落结构的周年调查。结果表明:湿地浮游植物年平均密度(3278 ind·L^(-1))以颤藻(Oscillatoria)(69.2%)和丝藻(Ulothrix)(17.2%)为主;生物量(0.039 mg·L^(-1))以圆筛藻(Coscinpdoscus)(66.2%)和菱形藻(Nitzschia)(23.5%)为主;浮游动物年平均密度(54.4 ind·L^(-1))以轮虫(68.1%)和桡足类(29.5%)为主,生物量(0.268 mg·L^(-1))以桡足类(61.2%)和轮虫(23.9%)为主;浮游生物各类群的第一优势种分别为颤藻、萼花臂尾轮虫(Brachionus calyciflorus)、短尾秀体溞(Diaphanosoma brachyurum)、汤匙华哲水蚤(Sinocalanus dorrii)和线虫;S2—S3断面水体营养盐浓度、群落生物量明显大于其他断面,且中潮位明显高于高潮位。水体中NH4_^+-N含量与浮游植物生物量和浮游动物生物量之间均有显著的线性回归关系;污染指数与轮虫生物量之间呈极显著正相关(P<0.001);滩涂湿地的中潮位区受内陆排水污染严重,而轮虫生物量显著上升和浮游动物种类丰度下降是群落的重要特征。

A seasonal investigation was conducted on the plankton community structure at five sampling profiles （S1-S3 for discharge area and S4-S5 for non-discharge area） in the areas with high and medium tide levels of the mudflat wetland of Hangzhou Bay in April （spring）, July （summer）, October （autumn）, 2010 and January （winter）, 2011, aimed to understand the characteristics of the plankton community and their relationships with environmental factors. In the wetland, the annual average density of phytoplankton was 3278 ind·L-1, being dominated by Oscillatoria （69.2%） and Ulothrix （17.2%）, and the biomass was 0.039 mg·L-1, being dominated by Coscinpdoscus （66.2%） and Nitzschia （23.5%）. The annual average density of zooplankton was 54.4 ind·L-1, being dominated by Rotifera （68.1%） and Copepoda （29.5%）, and the biomass was 0.268 mg·L-1, being dominated by Copepoda （61.2%） and Rotifera （23.9%）. The dominant species of each group of plankton were Oscillatoria, Brachionus calyciflorus, Diaphanosoma brachyurum, Sinocalanus dorrii, and Nematodes, respectively. The water nutrient concentrations and the biomass of plankton community were much higher at the profiles S2-S3 than at the other profiles, and much higher in the areas with medium tide level than with high tide level. The water NH4＋-N concentration was significantly linearly correlated with phytoplankton biomass and zooplankton biomass, and the pollution index had a significant positive correlation with rotifers biomass （P〈0.001）. The areas with medium tide level were seriously polluted by inland discharge, whereas the significant increase of rotifer biomass and the decline of zooplankton species richness were the important characteristics of the plankton community.