上海市中心城区河道浮游动物群落结构的周年变化

Annual variations of zooplankton community structure in Shanghai downtown rivers

于2007年11月—2008年10月,对上海市中心城区的午潮港、横港、朝阳河、曹杨环浜等4条河道中浮游动物的群落结构及其相关水环境指标进行了调查。共鉴定浮游动物63种,其中轮虫44种(69%),枝角类13种(21%),桡足类6种(10%),优势种主要为转轮虫(Rotaria rotatoria)、长足轮虫(R.neptunia)、萼花臂尾轮虫(Brachionus calyciflorus)、螺形龟甲轮虫(Keratella cochlearis)、前节晶囊轮虫(Asplanchna priodonta)、长肢多肢轮虫(Pol-yarthra dolichoptera)、大型溞(Daphnia magna)、发头裸腹溞(Moina irrasa)和广布中剑水蚤(Microcyclops leuckarti)。4条河道浮游动物的平均密度变动范围为726～2571ind.L-1;平均生物量为12.04～44.27mg·L-1。相关分析结果显示,浮游动物种群密度、生物量与溶解氧呈显著正相关(P<0.05),水体中的磷酸盐、硝酸盐氮和亚硝酸盐氮对浮游动物的群落结构有一定的影响。对河道中浮游动物群落结构的周年变化进行分析,发现不同河道中的浮游动物无明显的季节变化规律,总体上,浮游动物的种类组成和密度正在恢复和增加,表明城区河道水生态系统的初步治理已取得了一定的效果。

From November 2007 to October 2008,a monthly investigation was conducted to study the annual variations of zooplankton community structure and water environmental factors in the Wuchaogang River,Henggang River,Chaoyang River,and Caoyanghuanbang River of Shanghai downtown. A total of 63 species were identified,including 44 Rotifera （69%）,13 Cladocera （21%）,and 6 Copepoda （10%）. The dominant species were Rotaria rotatoria,R. neptunia,Brachionus calyciflorus,Keratella cochlearis,Asplanchna priodonta,Polyarthra dolichoptera,Daphnia magna,Moina irrasa,and Microcyclops leuckarti. In the four rivers,the zooplankton＇s average abundance ranged from 726 to 2571 ind·L^-1,and the biomass ranged from 12.04 to 44.27 mg·L^-1. Both the zooplankton community density and the biomass were significantly positively correlated with dissolved oxygen （P〈 0.05）,and the water body＇s phosphate,nitrate,and nitrite contents had definite effects on the zooplankton abundance and biomass. Based on the analysis on the annual variations of zooplankton community structure in the four downtown rivers,no significant seasonal variations were found. Overall,the zooplankton community structure and density were in recovering,suggesting that a better aquatic ecosystem was being constructed in the four downtown rivers.