2009年初夏长江口及毗邻海区表层浮游植物群落结构的色素表征

Phytoplankton community structures revealed by pigment signatures in Changjiang River Estuary and its adjacent sea areas in summer 2009

2009年6月对东海表层海水光合色素进行了高效液相色谱(HPLC)分析,通过藻类色素化学分类分析软件Chemical Taxonomy(CHEMTAX)获得了不同浮游植物对叶绿素a的贡献,研究了表层浮游植物群落结构的组成。结果表明:表层浮游植物的生物量与群落组成受温度、悬浮物质量浓度、营养盐等环境因素的影响,在水平分布上有着明显差异,具有区域性特征。长江河口区生物量不高,硅藻占绝对优势。长江冲淡水羽状锋是生物活动最为活跃的区域,Chla、硅藻特征色素Fuco和甲藻特征色素Peri等的高值均位于羽状锋附近,其中硅藻为优势种,其优势地位从近岸向外海逐渐降低,沿着长江冲淡水保持至123.5°E,在舟山群岛海域优势最明显。Chla的另一高值和金藻特征色素19’BF的高值位于浙闽沿岸,定鞭藻特征色素19’HF高值位于外陆架北部附近海域,而蓝藻特征色素Zea高值则位于台湾暖流控制区域,但生物量较低。东海中陆架海区,除个别站位以甲藻为优势种外,其余站位无明显的优势类群。

Based on the supplementary investigation for the Comprehensive Survey and Evaluation of the Coastal Seas of China in June 2009,HPLC analysis of the photosynthetic pigments were made for the water column of East China Sea and contributions of different phytoplanktons to chlorophyll a were obtained with chemical taxonomy（CHEMTAX）,and thus resulted in composition of the phytoplankton community structure.The mass concentration of surface Chl a ranged from 0.42 to 5.29 μg/dm3,with the highest value at the plume front area of Changjiang River.Except for 19＇HF,19＇BF,Zea and Allo,the high content areas of the characteristic pigments were all located to the northeast of the Changjiang diluted water plume,where is the most active area of biological activity in the estuary.The peak value of Chrysophytes characteristic pigment 19＇BF and another peak value of Chl a were located in coastal waters of Zhejiang and Fujian,while that of Prymnesiophytes characteristic pigment 19＇HF near the Cheju Island,and that of Cyanobacteria characteristic pigment Zea in the control area of the Taiwan Warm Current.Surface phytoplankton biomass and community composition were affected by the concentration of suspended solids,nutrients content and the ratio of key trophic elements.There were clear horizontal differences with a regional characteristic.The biomass in Changjiang River Estuary was low,and Diatoms accounted for an absolute advantage.Diatoms＇ dominance decreased gradually from the shore seawards,and kept along the Changjiang diluted water plume till 123.5°E,and the dominance was the most obvious in waters of Zhoushan Archipelago.Changjiang diluted water plume was the most active region of biological activities,where Diatoms were dominant.Except for Chrysophytes and Cyanobacteria,the rest of algae all distributed in certain contents.In waters near Cheju Island,Prymnesiophytes were the most abundant,while other algae distributed in a small amount.In the area of East China Sea continental shelf,there were no obvious dominant groups except for few stations where Dinoflagellates were dominant.The biomass in the areas affected by Taiwan Warm Current was lower,and Prymnesiophytes were the dominant group and Cyanobacteria were more abundant compared to other sea areas.