长江口中华鲟自然保护区附近水域浮游植物分布

DISTRIBUTION OF PHYTOPLANKTON AROUND YANGTZEESTURINE NATURE RESERVE FOR CHINESE STURGEON

根据2004年5月至2005年8月4个航次的调查数据,对长江口中华鲟自然保护区附近水域浮游植物分布进行调查分析。结果表明,调查水域物种丰富,共记录浮游植物6门68属132种,硅藻门的物种最多(37属93种),其次为绿藻(17属20种),甲藻、蓝藻、黄藻和裸藻相对较少;物种群落结构多样,有近海低盐性、外海高盐性、河口半咸水性和淡水性四大类群,浮游植物年平均丰度为305.28×104ind/m3,平水期(5、11月)>丰水期(8月)>枯水期(2月),中肋骨条藻(Skeletonema costatum)对物种之间细胞丰度分配比例和浮游植物细胞总丰度起关键性支配作用。长江径流、外海水系季节性消长直接影响到浮游植物物种组成与种群结构变化,浮游植物河口生态特征明显。

According to the data acquired from the 4 navigations from May 2004 to August 2005 ,the phytoplankton distribution around Yangtze Esturine Nature Reserve For Chinese Sturgeon was analyzed. The results showed there plenty of phytoplankton species were observed,wherein 132 species belonging to 6 phyla and 68 genera were recorded. Among the species observed,diatoms was most dominant（93 species belonging to 37 genera）,followed by chlorophytas（20 species belonging to 17 genera）,and dinoflagellates,cyanophytas, xanthophytas and cotaciums were relative low. The species number sequences of seasons was sping 〉winter〉summer〉autumn. There various communitie types mainly included low-salinity-offshore, highsalinity-outshore,sub-brackish water-estuary and fresh water. The annual mean density of phytoplanktonwas 305.28 × 10^4 ind./ma , and present flow period（May, Novermber） 〉high-flow period（Auguest） 〉 low flow period（February）. Sleeletonema costatum, was the key species, which dominated total biomass and cell density proportion among different phyla. The seasonal continuously change of outoshore water system and the Yangtze runoff influenced the species composition and community structure directly around the investigation area. Thus the phytoplankton community around Yangtze Esturine Nature Reserve For Chinese Sturgeon represented evident estuarine character.