Phytoplankton diversity and assessment of trophic state in Futian Mangroves in Shenzhen

通过监测深圳福田红树林水体浮游植物,掌握浮游植物多样性组成和时空分布特征,并利用浮游植物群落多样性指数结合生物量、数量,对水体营养状态进行评价。结果表明,浮游植物种类少,数量大。硅藻分布广泛,在种类和数量上占主导地位,优势种为微小小环藻(CyClOTEllA CASPIA)和诺氏海链藻(THAlASSIOSIrA nOrdEnSkI ldI)等,一些耐污染的藻类,如小颤藻(OSCIllATOrIA MInIMA)、裸藻(EuglEnASPP.)在特定季节成为一些站位的优势种。浮游植物种类组成时空变化显著,而数量的空间变化明显,季节差异不大。检测出富营养化指示种15种,中营养化指示种11种,贫营养化指示种9种。浮游植物的生物评价指数显示,深圳红树林水体处于中--富营养化状态,有向富营养化过渡的趋势,水体遭受严重污染,应注意加强对内陆径流和污水排放进入红树林的严格控制和管理。An investigation of phytoplankton diversity was carried out at sampling stations in Futian Mangrove Reserves,Shenzhen from Oct.2005 to Sep.2006.Based on four diversity indices(Shannon-Weaver diversity index,Pielou evenness index,Margalef abundance index and Dominant index),combined with the phytoplankton biomass and quantity,the assessment on the trophic state of water in Futian Mangrove Reserves was made.The results showed that the phytoplankton diversity of 51 taxa(including 1 variety and 9 unidentified taxa) belonging to 28 genera in 5 phyta were identified.The phytoplankton quantity in each season was high up to 106/L.Diatom was dominant in phytoplankton community in terms of species and quantity.Dominant taxa were diatoms such as Cyclotella caspia and Thalassiosira nordenskildi.While other pollution-tolerance taxa such as Oscillatoria minima and Euglena spp.became dominant in some stations in certain season.In contrast to a remarkable seasonal and spatial variation of species compositions,the phytoplankton quantities was changed little in season though they alternated with the sites in spatial.15 eutrophication indicators,11 mesotrophication indicators and 7 dystrofication indicators were identified.The relation to four diversity indices,phytoplankton biomass and quantity value,the trophic state of water health quality in Futian Mangrove Reserves were varied from mesotrophic to eutrophic as a whole.The water health quality tended to be eutrophication,in the state of extremely contamination.So the management and seriously control of the discharged wastewater should be enhanced.国家908项目(908-01-ST06;908-02-03-09

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

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 nordenskildi)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。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 nordenski?ldi 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.中国近海海洋综合调查与评价项目908-01-ST06和908-02-03-0