2010年秋季北部湾广西沿岸表层浮游植物分布特征

Phytoplankton distribution characteristics of Guangxi Beibu Gulf coast in the autumn of 2010

2010年9月5～15日对广西沿岸46个站位进行了浮游植物群落结构的凋查。调查结果表明:共鉴定出浮游植物59属,130种(含变种、变型),其中硅藻42属101种,占所有物种数的77.69%,占总细胞丰度的94.13%;甲藻12属24种,占物种数的18.46%,占总细胞丰度的3.56%。浮游植物平均细胞数量为(15.16±22.70)×104/L,变化范围为(0.43～114.89)×104/L,硅藻的平均细胞数量为(14.27±22.72)×104/L,变化范围为(0.12～114.48)×104/L;甲藻类的平均细胞数量为(0.54±0.82)×104/L,变化范围为(0.11～5.40)×104/L。浮游植物高值区主要位于防城港湾及钦州港外海处,在茅尾海、大风江附近海域、北海海域丰度较小,总体分布趋势为由西向东逐渐递减。主要优势种为拟旋链角毛藻、菱形海线藻、中肋骨条藻、环纹娄氏藻和斯托根管藻。调查海区浮游植物的多样性指数和均匀度指数的平面分布特征相似,均为外海高于沿岸海域,生物多样性和均匀度指数较高,浮游植物群集较成熟稳定。应用典范对应分析(CCA)发现磷酸盐和总氮是影响广西北部湾浮游植物物种分布格局最重要的因素;COD和透明度也起一定的作用。

We investigated the abundance and species composition of phytoplankton community in the coastal water of Guangxi from 5 to 15 in September 2010.A total of 130 species belonging to 59 genera were identified.Diatoms contributed to 77.69% of the total phytoplankton species number and 94.13%of the total phytoplankton cell abundance;followed by dinoflage1lates,which accounted for 18.46%of total phytoplankton species number and 3.56%of the total phytoplankton cell abundance.Phytoplankton abundance varied from 0.43×10^4/L to 114.89×10^4/L,the average density was 15.16×10^4/L,the average density of diatom was 14.27×10^4/L,the average density of dinoflagellate was 0.54×10^4/L,Phytoplankton abundance had a lower value in Maowei Sea,adjacent waters of Dafengjiang and Beihai sea area,the quantitative distributions of phytoplankton,presented a reduced tendency from east to west.The dominant species were Chaetoceros pseudocurvisetuss Mangin,Thalassionema nitzschioides Grunow,Skeletonema costatum Cleve,Lauderia annulata Cleve and Rhizosolenia stolterfothii Peragallo.The Shannon-Wiener diversity indices and Pielou＇s evenness of phytoplankton community with a similar plane distribution were higher off the coast than on the coastal area,the phytoplankton assemblage was comparatively stabilizing.Canonical correspondence analysis（CCA） was applied to explore the relationship between phytoplankton species and environmental parameters,the results showed that phosphate concentration and the total nitrogen were the most important factors,nitrate,COD and transparency were secondary important factors,which influencing the phytoplankton species distribution patterns.