上海市滩涂夏季底栖硅藻初步研究

Benthic Diatoms from the Tidal Flat of Shanghai, China, during 2005 Summer

摘要:

报道了上海市夏季滩涂底栖硅藻的种类组成和生态分布的情况。样品于2005年8月从7个站点中采集，经处理、镜检观察，从中鉴定出硅藻98个分类单位，包括种、变种和变型，分别隶属于2纲7目10科31属。舟形藻（Navicula）最多，共发现15个分类单位；其次为菱形藻（Nitzschia），有10个分类单位。其中Cyclotella meneghiniana, Gyrosigma spencerii, Surirella ovata为优势种，Fragilaria capucina, Gyrosigma attenuatum, Naicula acceptata等为常见种，Melosira italica, Coscinodiscus wittianus , Navicula pygmaea等只在个别站点采到。数量分析表明，硅藻总细胞丰度变化为7.0×10⁶-28.5×10⁶ cells m^-2，平均为17.39×10⁶ cells m^-2，在径流入海口处硅藻数量相对较多，其中淡水种比海生种多，这主要是因为长江口近岸河口水域是多种水系相混合的水体，淡水入海带来较多的淡水种类。

Abstract:

The species composition and ecological distribution of benthic diatoms were investigated in the tidal flat of Shanghai, China. Benthic samples were collected from 7 sites in August, 2005. Ninety-eight taxa including 31 genera and 10 families were identified. Navicula (15 taxa) was the most abundant followed by Nitzschia (10 taxa). The dominant species were Cyclotella meneghiniana, Gyrosigma spencerii, Surirella ovata and the common ones were Fragilaria capucina, Gyrosigma attenuatum, Naicula acceptata, etc.. The occasional species were Melosira italica, Coscinodiscus wittianus and Navicula pygmaea. Quantitative analysis showed that the total diatom cell density ranged from 7.0×10⁶-28.5×10⁶ cells m^-2, with an average of 17.39×10⁶ cells m^-2. More diatoms were found at the convergence of runoff and seawater, and freshwater species were more abundant than saltwater ones, mainly because Yangtze River estuary waters are composed of various waters, into which freshwater brings many freshwater species.