Although diatom has been widely used in biological or ecological monitoring of rivers, there is little information on diatom communities in most of Chinese rivers. In this study, we reported periphytic diatoms on artificial substrata( tile) in the Huizhou section of the Dongjiang River. We analyzed seasonal variations of the species composition and the relationship between the relative abundance and seasonal environmental factors at five sampling stations in 2010. A total of 153 periphytic diatom species, belonging to 40 genera, were identified. Dominant genera included Achnanthidium, Gomphonema, Melosira, Navicida, Nitzschia and Syne-dra. Gomphonema parvulum and Nitzschia palea were the common species in all the sampling sites with relative abundance > 1% . However, the relative abundance of the two species varied largely in seasons. Chi. a concentrations of the periphytic algae were positively correlated with the temperature. Redundancy analysis showed that water temperature, DO, NH4+ -N, PO4 ~ -P, conductivity and pH were the major factors influencing the community structure of periphytic diatoms. Furthermore, hydrographic condition was crucial to some mobile species such as Nitzschia palea, whose relative abundance was low in summer mainly due to flushing in flood season.%硅藻群落结构特征是反映河流水生态状态的重要生物指标,但我国多数河流中还缺少硅藻种类组成与季节变化的基本数据.2010年用瓷砖片作为人工基质研究东江惠州河流段附着硅藻群落结构的季节性变化,共鉴定出附着硅藻40属153种(包括亚种和变种),主要的优势属有曲壳藻属(Achnanthidium)、异极藻属(Gomphonema)、直链藻属(Melosira)、舟形藻属(Navicula)、菱形藻属(Nitzschia)、脆杆藻属(Synedra)等.Gomphonema parvulum和Nitzschia palea为该河流段的广泛性藻种,且相对丰度的季节性变化明显.RDA分析表明,水温、DO、NH4+-N、PO43--P、电导率、pH值等对附着硅藻群落结构有重要影响.在丰水期,水量对于运动能力较强的N.palea的相对丰度具有明显的影响.
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