深圳红树林区浮游植物时空变化与水质要素的关系

在探讨深圳福田红树林区浮游植物群落结构及种群数量变化规律的基础上,对红树林区不同水质环境中浮游植物时空变化进行了研究,初步分析主要水质因子与浮游植物密度时空变化的相关关系。分析表明,福田红树林区浮游植物有5门28属51种(含未知9种),以硅藻门种类为主,优势种为微小小环藻(Cyclotella caspia)和诺氏海链藻(Thalassiosira nordenskiöldi)等,蓝藻、绿藻能发展成为优势类群,优势种为小颤藻(Oscillatoria minima)和小球藻(Chlorella vulgaris)等。浮游植物种类组成季节变化明显,空间变化显著。浮游植物密度空间变化明显,季节差异不大。各季度的浮游植物密度较高,达到106cells·L^-1的级别。由于接纳生活污水、工业废水、养殖废水等陆源污水,5个站位的主要水质因子受污水排放影响明显,站位受陆源污水影响的顺序依次为:Ⅳ>Ⅱ>Ⅴ>Ⅰ>Ⅲ,污水排放进入红树林区的水域水质显著区别于完全海水水域。陆源污水输入对浮游植物密度时空变化造成显著影响,浮游植物密度与总氮浓度、盐度相关性较好,与总氮成显著负相关,与盐度成显著正相关。

Seasonal and spatial variation of phytoplankton and relationship with water-quality factors in Futian Mangroves of Shenzhen

Phytoplankton community were studied at 5 sites in Futian Mangrove Reserves of Shenzhen from Oct.2005 to Sep.2006.The species composition,densities and distribution of phytoplankton,in seasonal and spatial scale,were studied.Main water-quality factors were preliminary examined for their relations to phytoplankton densities.As result a total of 51 taxa (including 1 variety and 9 unidentified taxa) belonging to 28 genera in 5 phyta were identified.It showed that diatoms,such as Cyclotella caspia and Thalassiosira nordenskiöldi dominated in 4 seasons in most sites.Among the others,species of Cyanobacteria and Chlorophyta,such as Oscillatoria minima and Chlorella vulgaris,only dominated at a few sites.In contrast to a remarkable seasonal and spatial variation of species compositions,the phytoplankton densities changes little in season though they alternated with sites in spatial.Phytoplankton density was high reaching 10⁶ cells·L^-1 in 4 seasons.Water qualities changed with seasons in 5 sites due to the influence of domestic and industrial wastewater.The sites contaminated by the sewage are in sequence of Ⅳ>Ⅱ>Ⅴ>Ⅰ>Ⅲ,the pollution made water quality quite different with that of seawater in the open sea.Correlations of phytoplankton density with total nitrogen and salinity were found.It showed that the phytoplankton density changed positively with salinity but negatively with the total nitrogen.