作 者 ：杨清良,林更铭
期 刊 ：生态学报 2007年 27卷 2期 页码：465~476
Keywords:phytoplankton, distribution variation, red tide, multivariate analysis, Xiamen seas,
摘 要 ：根据2000年6月至7月夏季藻华期在11个监测站10个航次获取的表层浮游植物和现场测定的理化参数数据，采用多元分析方法揭示浮游植物聚群在污染胁迫下的动态特征。结果表明：(1）该区调查期间浮游植物群落的物种多样性时空变异显著，各站多样性指数值(H′)变动在0.45～4.23之间；(2）聚类分析和多维排序（MDS）结果显示，浮游植物聚群可分为3个与浮游植物阶段性演替以及各水域间不同的理化特征相关联的群落。群落Ⅰ系2000年6月赤潮暴发时主要出现于西海域的低盐港湾群落，由微型（nano-）浮游植物组成，包括硅藻门的角毛藻、骨条藻等属种类以及金藻门的单鞭金藻属种类等，如中肋骨条藻（Skeletonema costatum ）、聚生角毛藻（Chaetoceros socialis ）等和一种单鞭金藻（Chromulina sp.）(未鉴定到种，藻径3～5μm)，它们是赤潮原因种。群落Ⅱ和群落Ⅲ都以小型（micro-）浮游植物占优势。群落Ⅱ为赤潮前后广泛出现于调查区各水域的亚热带近岸广布群落，代表种有具槽帕拉藻（Paralia sulcata）、翼鼻状藻（Proboscia alata）、菱形海线藻（Thalassionema nitzschioides）和冰河拟星杆藻（Asterionellopsis glacialis）. 群落Ⅲ主要分布于本海区东-东北部，由我国东南沿海常见的近海广布性种类组成，包括旋链角毛藻（Chaetoceros curvisetus ）、地中海细柱藻（Leptocylindrus mediterraneus）、尖刺伪菱形藻（Pseudo-nitzschia pungens）、优美施罗藻（Schroederella delicatula）和斯氏几内亚藻（Guinardia striata）等; (3)丰度-生物量曲线（ABC）分析结果显示，当微藻赤潮出现时，数值丰度的K-优势曲线位于生物量K-优势曲线上方，而无赤潮时2条曲线大体上重叠。其模式可指示厦门海区西部海域污染严重以及东-东北部中度污染的状况；(4) 根据各航次全部调查数据所作的PCA分析得到的前3个最主要成分，包括浮游植物丰度和溶解氧，铵氮和磷酸盐，盐度和温度等，大约解析本调查总差异的78.5%。
Abstract:Algal blooms have been increasing in frequency in recent years in Xiamen seas, primarily in the western Xiamen Harbour, with occurrence in the spring and summer almost every year. There have been extensive reports on the phytoplankton in Xiamen seas，but few deals with the characterization of population dynamics of the blooms. The present study analyzes the community structure of the phytoplankton collected on 10 cruises from 11 stations during the summer red tide of 2000 (June to July) in order to understand the dynamics of phytoplankton assemblages under pollution stress conditions. The results show that: (1)the spatial and temporal variations of the phytoplankton diversity index (H′) are large during the survey period，ranging from 0.45 to 4.23; (2) based on the results of the multivariate analysis (cluster analysis and multi-dimensional scaling), the phytoplankton assemblages can be divided into three groups associated with the specific stages of phytoplankton succession and with the different physic-chemical features associated with each sampling region. Group I was composed of the samples collected from the low salinity stations in western Xiamen Harbour in June, 2000. The community was consisted of nanophytoplankton flora including the Bacillariophyta (such as Chaetoceros socialis, Skeletonema costatum) and the Chrysophyta (such as Chromulina sp.). These species were responsible for the red tide. Groups Ⅱ and Ⅲ were both dominated by microphytoplankton assemblages. Group II was represented by the subtropical coastal eurytopic species commonly found in the studied area before and after red tide blooms, such as Paralia sulcata，Proboscia alata，Thalassionema nitzschioides and Asterionellopsis glacialis. Group Ⅲ included mainly the samples collected from the stations in the eastern-northeastern Xiamen seas，represented by neretic species that are ubiquitous in the coastal areas of southeast China, including Chaetoceros curvisetus，Leptocylindrus mediterraneus，Pseudo-nitzschia pungens，Schroederella delicatula and Guinardia striata; (3) in the Abundance-Biomass Comparison analysis, the K-dominant curve for numerical abundance lies below that for the biomass when the nanophytoplankton bloom occurred, while both curves largely coincided during non-bloom periods. Such a pattern may indicate the heavily polluted condition in the western waters and the moderately polluted conditions in the eastern-northeastern waters in the Xiamen seas; 4) based on the results of principal component analysis, the first three components accounted for 78.5% of the total variance and the most important factor loadings include species richness, dissolved oxygen, NH+4-N and PO-4-P, salinity, and temperature.