长江口及邻近海域浮游植物色素分布与群落结构特征

Phytoplankton Pigment Patterns and Community Structure in the Yangtze Estuary and Its Adjacent Areas

根据2009年5月、11月和2010年6月对长江口及邻近海域调查结果,利用反相高效液相色谱技术(RP-HPLC)对该海域浮游植物特征色素组成和分布进行了研究,并应用CHEMTAX软件研究了浮游藻类群落组成.结果表明,在长江口及邻近海域分离鉴定了21种浮游植物色素,主要的色素种类为叶绿素a、多甲藻黄素、岩藻黄素、19'-丁酰基氧化岩藻黄素、19'-已酰基氧化岩藻黄素、叶绿素b、硅甲藻黄素、别黄素和玉米黄素,以叶绿素a的含量最高,其次是岩藻黄素,其他色素对总色素含量贡献较低.2009年5月和2010年6月航次期间通过对色素的分析检测到甲藻和硅藻藻华.主要特征色素的含量及分布特征与盐度、营养盐等环境因子关系密切.特征色素组成和分布特征表明,研究海域浮游植物种类主要存在硅藻、甲藻、隐藻、绿藻、蓝藻、定鞭藻、金藻和青绿藻等8个类群.CHEMTAX分析结果表明,2009年5月硅藻、甲藻和绿藻是最主要的类群;2009年11月硅藻在群落结构中处于绝对优势;2010年6月,硅藻、甲藻和隐藻贡献了62.5%的叶绿素a生物量,蓝藻所占的比重明显有所上升.浮游植物群落结构在空间分布上有着明显差异,呈现区域性特征,硅藻、绿藻和隐藻在近岸海域所占比重较高,而定鞭藻、金藻和蓝藻在外海区域的站位对生物量的贡献明显上升.

Three cruises were carried out in the Yangtze Estuary and its adjacent areas in May,November,June during 2009-2010.The spatial variations of phytoplankton community structure were investigated based on RP-HPLC analysis of pigments and CHEMTAX processing of the pigment data.21 kinds of pigments were detected,among which chlorophyll a,peridinin,fucoxanthin,19＇butanoyloxyfucoxanthin,19＇-hexanoyloxyfucoxanthin,chlorophyll b,diadinoxanthin,alloxanthin and zeaxanthin were the major pigments in the Yangtze Estuary and its adjacent areas.Chlorophyll a was the most abundant in all pigments,followed by fuxoxanthin.Other pigments generally contributed a minor proportion to the total pigments.High concentrations of fucoxanthin and peridinin were observed in May 2009 and June 2010,indicating blooms of diatoms and dinoflagellates.The results showed that the composition and distribution of phytoplankton pigments were influenced by environmental factors.The phytoplankton community,as determined by biomarker pigment concentration using HPLC and CHEMTAX,was composed mainly of diatoms,dinoflagellates,cryptophytes,chlorophytes,cyanobacteria,prymnesiophytes,chrysophytes and prasinophytes.The dominant algal groups were diatoms,dinoflagellates and chlorophytes in May 2009.The phytoplankton community was characterized by high contribution of diatoms in November 2009.Diatoms,dinoflagellates and cryptophytes accounted for 62.5% of chlorophyll a in June 2010,and the relative abundance of cyanobacteria was higher in this cruise.The spatial variations of phytoplankton community structure featured distinct regionality.Diatoms,chlorophytes and cryptophytes were the main groups in the inshore waters,and the abundances of prymnesiophytes,chrysophytes and cyanobacteria were increasing from inshore to the open sea.