三峡水库坝前水域浮游植物群落时空动态研究

THE SPATIO-TEMPORAL DYNAMICS OF PHYTOPLANKTON COMMUNITY STRUCTURE IN THE HEAD REGION OF THE THREE GORGES RESERVOIR

于2012—2013年对三峡水库坝前水域浮游植物组成、优势种、密度、生物量及多样性进行了周年季度调查,共鉴定浮游植物151种属,其中绿藻门71种,硅藻门47种,蓝藻门20种,隐藻门和甲藻门各4种,裸藻门和金藻门各2种,黄藻门1种。浮游植物优势种的季节更替明显,夏季和秋季优势种类为硅藻和绿藻,冬季为硅藻、蓝藻和绿藻,春季为绿藻、硅藻和隐藻。浮游植物年均密度和生物量分别为3.95×106 ind./L和4.078 mg/L,空间差异表现为支流和库湾远高于干流,季节动态表现为夏季最高,春季和冬季次之,秋季最低。三峡水库坝前水域浮游植物多样性指数偏低,水体污染类型属于α-中污染。研究为客观了解三峡水库坝前水域浮游植物群落的空间分布与季节变化特征提供一定的参考依据。

In this study, we explored the seasonal change in the structure of the phytoplankton community in the head region of the Three Gorges Reservoir （TGR）. Field sampling was carried out in August （summer） and November （au- tumn） of 2012 and in January （winter） and April （spring） of 2013. Eight phyla and 151 genera and species were identi- fied, including 71 species of Chlorophyta, 47 species of Bacillariophyta, 20 species of Cyanophyta, 4 species of Pyrro- phyta and Cryptophyta, 2 species of Chrysophyta and Euglenophyta, and 1 species of Xanthophyta. Bacillariophyta and Chlorophyta were the most abundant phyla. There were remarkable seasonal variations in the composition of the domi- nant phytoplankton species. The dominant species in summer were Cyclotella sp., Pandorina morum, Chlamydomonas sp., Chlamydomonas conica, and Eudorina elegans. The dominant species in autumn were Cyclotella sp., Melosira sp., and Chlorella vulgaris. In winter, the dominant species were Cyclotella sp., Aphanizomenon sp., Phormidium sp., Me- rismopedia tenuissima, Pseudanabaenaceae sp., and Lyngbya sp. In spring, the dominant species were Chlamydomonas sp., Cyclotella sp. and Chroomonas acuta. The abundance of phytoplankton peaked in summer and reached the lowest in autumn. The annual density and biomass were 3.950× 10^6 ind./L and 4.078 mg/L respectively. The abundance of phyto- plankton in the bay and the tributary was higher than that in the mainstream. The water body in the head of region TGR was lonsidered to be α-mesosaprobic according to the diversity index of the phytoplankton community. Our study pro- vided insights into the spatial and temporal dynamics of the phytoplankton community structure and will helpus develop strategies to improve the water quality in the TGR.