2009年夏季东海浮游植物群集

Phytoplankton Assemblages in the East China Sea in Summer 2009

2009-08-18—29在东海海域(25°00′～32°00′N,120°30′～127°30′E)52个站位进行水文、化学和生物的综合调查,对调查海域的浮游植物群集运用Utermhl方法进行分析,共鉴定出浮游植物5门68属198种(含13个未定种)。浮游植物群集主要由硅藻和甲藻组成,还有少量的蓝藻、金藻和绿藻,优势物种为菱形海线藻(Thalassionemanitzschioides)、尖刺伪菱形藻(Pseudo-nitzschia pungens)、伏氏海线藻(Thalassionema foluenfeldii)、骨条藻(Skeletonemaspp.)、锥状斯克里普藻(Scrippsiella trochoidea)、柔弱伪菱形藻(Pseudo-nitzschia delicatissima)、简单裸甲藻(Gymnodinium simplex)、微小原甲藻(Prorocentrum minimum)、具槽帕拉藻(Paralia sulcata)和矮小短棘藻(Detonula pumila)等。浮游植物物种以广温广布型为主,长江口近岸海域出现少数半咸水种,台湾暖流流经海域和外侧黑潮水海域出现部分暖水性种。调查海域浮游植物细胞丰度为0.296×103～2 135.200×103个.L-1,平均值为58.031×103个.L-1;硅藻占浮游植物细胞丰度的比例最大,为0.296×103～2 112.000×103个.L-1,平均值为52.833×103个.L-1;其次为甲藻,细胞丰度为0.296×103～527.644×103个.L-1,平均值为11.271×103个.L-1。浮游植物细胞丰度表层分布以硅藻为代表,高值区出现在长江冲淡水影响的长江口近岸和闽浙沿岸海域及受上升流影响的台湾岛东北部海域,甲藻只在长江口东北部即南黄海南部海域出现丰度高值。细胞丰度在水体中的垂直分布变化为随水深增加逐渐降低。细胞丰度的断面分布基本呈近岸高于远岸趋势,E断面和F断面远岸站位也有丰度高值区出现。调查区Shannon-Wiener多样性指数和Pielou均匀度指数均在长江口近岸出现低值,其中Shannon-Wiener多样性指数高值区出现在调查区南部海域,Pielou均匀度指数高值区出现在调查区东南部海域。调查区浮游植物优势物种与环境因子的典范对应分析结果显示,伏氏海线藻、骨条藻、尖刺伪菱形藻和矮小短棘藻等硅藻优势物种与磷酸盐呈正相关性,锥状斯克里普藻、简单裸甲藻和微小原甲藻等甲藻优势物种和各环境因子相关性不明显。

A comprehensive survey was carried out in the area （25°00＇--32°00＇N, 120°30＇- 127°30＇E）of the East China Sea from 18th to 29th of August 2009 and the phytoplankton assemblages collected in the surveyed area were analyzed by means of Utermohl method. Totally 198 taxa, which belong to 68 genera of 5 phyla, have been identified. The phytoplankton community is mainly composed of Bacillariophyta and Di nophyta, with a few species of Cyanophyta, Chrysophyta and Chlorophyta being present. The dominant species are Thalassionema nitzschioides, Pseudo-nitzschia pungens, Thalassionema frauenf eldii, Skeletonema spp. , Scrippsiella trochoidea , Pseudo-nitzschia delicatissima , Gymnodinium simpleac , Prorocentrum minimum, Paralia sulcata, Detonula pumila. Most of the phytoplankton ecotypes are neritic cosmo politan species and some warm and oceanic species are also present in the surveyed area as a result of the influence of Taiwan Warm Current and Kuroshio Current. The cell abundance of phytoplankton ranges from 0. 296 ×10^3 cells· L-1 to2 135. 200×10^3 cells. L -1, with an average being 58.031×10^3 cells. L-1, of which Bacillariophyta ranks the first and ranges from 0. 296 × 10^3 cells · L-1 to 2 112. 000 × 10^3 cells · L -1 with an average of 52. 833 ×10^3 cells · L-1, followed by Dinophyta, ranging from 0.296×10^3 cells · L -1 to 527.644×10^3 cells· L-1 with an average of 11. 271×10^3 cells· L -1 Horizontally, the cell abundance is mainly dominated by Bacillariophyta and its high values occur in the Changjiang estuary and the sea northeast of Taiwan Island, and Dinophyta is only concentrated in the area northeast of Changjiang estuary. Vertically, the cell abundance of phytoplankton is concentrated in the surface water and decreases gradually downwards. In the transectional direction, the cell abundance tends to be higher in the inshore area than in the offshore area, except for the stations in the offshore area of Section D and F, where the value of cell abundance is high due to the upwelled subsurface Kuroshio Current. The canonical correspondence analysis shows that the dominant species of Bacillariophyta correlate positivly well to phosphate, whereas the dominant species of Dinophyta shows little correlation to the environmental parameters.