围垦对椒江口夏季浮游植物群落结构和多样性的影响

通过对椒江口(28.67°~28.69°N,121.45°~121.62°E)浮游植物进行的3次采样调查(2007年7月、2008年7月和2010年8月),并与历史数据进行比较,共鉴定出浮游植物5门,167种,三个年份分别为101、96和117种;浮游植物细胞丰度分别为20.34×10~3个/L、266.94×10~3个/L和66.94×10~3个/L;Shannon-Wiener指数(H')分别为1.95、0.60和0.40.围垦前和围垦结束后优势种包括硅藻(Bacillariophyta)和甲藻(Pyrrophyta),如琼氏圆筛藻(Coscinodiscusjonesianus)、辐射圆筛藻(Coscinodiscus radiatus)、中肋骨条藻(Skeletonema costatum)和柔弱根管藻(Rhizosolenia delicatula)等;围垦中只有硅藻,如洛氏角毛藻(Chaetoceros lorenzia—nus)和布氏双尾藻(Ditylum brightwellii).围垦促进了浮游植物细胞丰度的大幅度提升,但改变了浮游植物群落结构,降低了其稳定性和均衡性.CCA分析表明,pH、温度、氮/磷/硅营养盐、溶解氧和化学需氧量是影响浮游植物群落结构的水质参数;影响绿藻(Chlorophyta)、硅藻、蓝藻(Cyanophyta)和甲藻的主要水质参数分别为溶解氧、石油、温度和化学需氧量.长时间尺度与短时时间尺度分析得出相似的结论,围垦前后椒江口水质、浮游植物群落结构及生物多样性均发生相应变化.

Effects of reclamation on phytoplankton community structure and biodiversity in Jiaojiang Estuary

Investigations on phytoplankton of Jiaojiang Estuary（28.67°~28.69°N, 121.45°~121.62°E） were carried out in July 2007, July 2008, and August 2010, and compared with historical data. 5 Phylums and 167 species were identified in the three investigations which were 101, 96 and 117 respectively before，inning and after reclamation. Cell abundance of phytoplankton were 20.34×10³ cell /L, 266.94×10³ cell /L and 66.94×10³ cell /L, and Shannon-Wiener Index of phytoplankton were 1.95, 0.60 and 0.40 respectively. Dominant species of phytoplankton included Bacillariophyta and Pyrrophyta before and after reclamation, such as Coscinodiscus jonesianus, Coscinodiscus radiatus, Skeletonema costatum, Rhizosolenia delicatula, but only Bacillariophyta existed inning reclamation, such as Chaetoceros lorenzianus and Ditylum brightwellii. Reclamation promoted the enhancement of cell abundance but reduced the stability and balance of phytoplankton community structure. CCA analysis showed that pH, temperature, nitrogen/phosphorus/silicon nutrients, dissolved oxygen and chemical oxygen demand were the main water quality parameters affecting community structure of phytoplankton. The main water quality parameters affecting Chlorophyta, Bacillariophyta, Cyanophyta and Pyrrophyta were dissolved oxygen, oil, temperature and chemical oxygen demand respectively. Long time scale and short time scale analysis come to similar conclusions that water quality , community structure and biodiversity of phytoplankton have changed before and after reclamation of Jiaojiang Estuary.