State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, PR China.
Sci Total Environ. 2011 Sep 1;409(19):3820-8. doi: 10.1016/j.scitotenv.2011.06.041. Epub 2011 Jul 12.
Reservoirs can provide suitable conditions for cyanobacterial bloom development, which may impact on water quality and biological communities. Weekly surveys in a cyanobacterial bloom process were carried out in the mainstream and Xiangxi Bay of the Three Gorges Reservoir (China), from June 6 to July 18 in 2008. By application of the phytoplankton functional group approach, the spatiotemporal pattern, impact factors, and the ecological status based on Q index (assemblage index) were analyzed. The depth of euphotic layer was apparently the key factor driving the phytoplankton functional group variations. Longitudinal patterns of phytoplankton distribution were detected during this bloom: in the beginning phase, groups D (mainly Stephanodiscus hantzschii) and B (Cyclotella stelligera) dominated in the mainstream of the Three Gorges Reservoir and the mouth area of Xiangxi Bay, group Y (Cryptomonas species) dominated in the upper area, while groups J (mainly Pediastrum duplex), F (mainly Sphaerocystis schroeteri) and G (Pandorina morum and Eudorina elegans) were important in other areas; in the mid phase, group M became absolutely dominant in the whole region; and in the ending phase, besides groups M and Y, groups X2 (Chroomonas acuta, Pyramimonas nanella, etc.) and Lo (Ceratium hirundinella) became more important in the lower and upper area respectively. Generally the ecological status was bad, temporally varied with the bloom process. No spatial difference of ecological status was found in the mainstream, while longitudinal patterns in Xiangxi Bay were detected for different phases: firstly a few sites had relatively better status than the others, then nearly all the sites were in the bad condition, and at last the status in the downstream was better than that in the upstream. The longitudinal patterns of ecological status were related to phytoplankton distribution, disturbed by jacking from the downstream and flood from the upstream of Xiangxi Bay.
在 2008 年 6 月 6 日至 7 月 18 日期间，对三峡水库主流和香溪河湾进行了为期一周的蓝藻水华过程调查。应用浮游植物功能群方法，分析了时空格局、影响因素以及基于 Q 指数（组合指数）的生态状况。透光层深度显然是驱动浮游植物功能群变化的关键因素。在水华过程中检测到浮游植物分布的纵向格局：在起始阶段，群体 D（主要是 Stephanodiscus hantzschii）和 B（Cyclotella stelligera）在三峡水库主流和香溪河湾口区域占主导地位，群体 Y（Cryptomonas 种）在上游区域占主导地位，而群体 J（主要是 Pediastrum duplex）、F（主要是 Sphaerocystis schroeteri）和 G（Pandorina morum 和 Eudorina elegans）在其他区域也很重要；在中期，群体 M 绝对占主导地位；在结束阶段，除了群体 M 和 Y 之外，群体 X2（Chroomonas acuta、Pyramimonas nanella 等）和 Lo（Ceratium hirundinella）在下游和上游区域变得更加重要。总体而言，生态状况较差，随水华过程而变化。在主流区域未发现生态状况的空间差异，而在香溪河湾则检测到不同阶段的纵向格局：首先，少数站点的状况相对较好，然后几乎所有站点的状况都较差，最后下游站点的状况优于上游站点的状况。生态状况的纵向格局与浮游植物分布有关，受到香溪河湾下游顶托和上游洪水的干扰。
