汉江上游浮游植物的群落结构及周年变化

Structure and annual variation of phytoplankton community at upstream of Hanjiang River

【目的】研究汉江上游浮游植物的群落结构,为汉江上游水环境保护和水产养殖提供基础资料。【方法】在汉江上游汉中市境内的烈金坝、梁西渡、南柳渡、蒙家渡和黄金峡5个采样点,于2011年1,3,5,7,9,11月份分别采样,统计各样点浮游植物的种类数、细胞密度和Margalef多样性指数,分析浮游植物的群落结构及周年变化规律。【结果】从汉江上游5个采样点,共鉴定到浮游植物108种(包括变种),隶属于6门43属。其中,硅藻门种类最多,共16属48种;绿藻门次之,共12属23种;蓝藻门6属12种;裸藻门3属10种;甲藻门3属8种;金藻门3属7种。优势种为简单舟形藻(Navicula simplex)、尖针杆藻(Synedra acus)、普通等片藻(Diatoma vulgare)、颗粒直链藻(Melosira granulata)、卵形衣藻(Chamydomonas ovalis)、纤细新月藻(Closterium gracile)和棒形鼓藻(Gonatozygon monotaenium)。浮游植物细胞密度周年变化为48.53×104~121.13×104 L-1,Margalef多样性指数周年变化为3.01~4.10。【结论】汉江上游浮游植物的群落结构属于硅藻型群落,其种类数和细胞密度周年变化动态都呈现单峰型。

【Objective】Structure of phytoplankton community at upper Hanjiang River was investigated to provide information for environmental protection and aquaculture.【Method】Water samples were collected at five stations in Hanzhong city(Liejinba,Liangxidu,Nanliudu,Mengjiadu and Huangjinxia)in January,March,May,July,September,and November 2011.Annual variation of phytoplankton community was analyzed using number of species,cell density and Margalef index.【Result】A total of 108phytoplankton species(including variants)belonging to 43genera in 6phyla were identified from the samples.Bacillariophyta(48species of 16genera)dominated the phytoplankton community,followed by Chlorophyta(23species of 12genera),Cyanophyta(12species of 6genera),Euglenophyta(10species of 3genera),Dinoflagellate(8species of 3genera),and Chrysophyta(7species of 3genera).Dominant species were Navicula simplex,Synedra acus,Diatoma vulgare,Melosira granulata,Chamydomonas ovalis,Closterium gracile,and Gonatozygon monotaenium.The density of phytoplankton increased from 48.53×104 to 121.13×104 L-1.The Margalef index of the phytoplankton community ranged from 3.01to 4.10.【Conclusion】Structure of phytoplankton community at upstream of Hanjiang River was diatom type,and the annual variation patterns of both species abundance and density were in single-peak shape.