疏浚后杭州西湖的桡足类

本文调查了疏浚后杭州西湖(小型、浅水、富营养化湖泊)四个采样站(Ⅰ-Ⅳ)桡足类的密度、生物量和多样性指数,并对桡足类生物量与水质理化因子之间进行了相关分析．共发现桡足类9种,其中哲水蚤3种,剑水蚤6种．疏浚后,桡足类群落密度随着引水水流路程的加大而逐渐增大,多样性指数逐渐下降．桡足类群落丰度夏秋季明显大于冬春季．汤匙华哲水蚤(Sinocalanus dorrii)成体在营养水平较低的Ⅰ站(TLI=55．3)具有较大的密度和生物量,其分市沿着引流方向逐渐下降,而哲水蚤的桡足幼体则沿引流方向逐渐增加;粗壮温剑水蚤(Thermocyclops dybowskii)成体在营养水平较高的Ⅱ-Ⅳ站(TLI=62．7-63．5)具有较大的密度和生物量;疏浚使底柄种类猛水蚤(Harpacticoida)消失了.疏浚对哲水蚤密度分布分异的影响较大,对剑水蚤密度分布分异的影响较小．桡足类群落Ⅱ-Ⅲ站桡足类生物量随水体叶绿素a、高锰酸盐指数和总磷含量的升高而显著增加,随水体透明度的增大而显著下降．

A Study on the Copepoda community in West Lake, Hangzhou after dredging

Based on the data of the species abundance, biomass, diversity index of Copepoda and regression analysis between its biomass and factors of the water quality were studied at stations (from I to IV ) of West Lake Hang-zhou.a shallow eutrophic lake after dredging treatment. During the survey in 2003 , 9 species of Copepoda (3 Cal-anoida and 6 Cyclopoida) were identified from the quantitative samples. The density of Copepoda community increased after the drawing water current, but diversity index decreased. The abundance of Copepoda was much higher in Summer-Autumn than that in Winter - Spring season. Sinocalanus dorrii adults was more abundant at Station I with relatively lower trophic status. (TLI =55.3) , decreased along drawing water current, and Calanoida copep-odids density increased following the water current, while Thermocyclops dybouiskii adults was more abundant at Stations II - IV with relatively higher trophic status (TLI =62. 7 -63.5), Harpacticoida disappeared after dreding treatment. The effect of dreding treatment on Calanoida community heterogeneity of distribution was much stronger than that on Cyclopoida community. The biomass of Copepoda was positively correlative with Chlorophyll-a, CODMn and total phosphorus, while negatively with water transparency at Stations II -III.