连云港邻近海域网采浮游植物分布特征及其影响因素

Community composition of net-collected phytoplankton and its relation to environmental factors near Lianyungang sea area

根据2014年8月(夏季)、2014年11月(秋季)、2015年1月(冬季)和2015年5月(春季)对连云港邻近海域的网采浮游植物的调查,共鉴定出浮游植物8门68属155种(含变种、变型),主要由硅藻(115种)和甲藻(30种)组成.冬季细胞丰度(230.13×10~4cells/m^3)显著高于春(24.67×10~4cells/m^3)、夏(119.78×104cells/m^3)、秋(90.25×10~4cells/m^3)三季,优势种主要有密连角毛藻(Chaetoceros densus)、中肋骨条藻(Skeletonema costatum)、三叶原甲藻(Prorocentrum triestinum)、卡氏角毛藻(Chaetoceros castracanei)和微小细柱藻(Leptocylindrus minimus)等.浮游植物群落参数(种类数、细胞丰度、Shannon-Wiener多样性、Margalef丰富度、Pielou均匀度等指数)和环境因子(温度、盐度、p H值、DO、COD和营养盐)均存在季节显著差异.聚类、多维尺度和相似性分析结果也表明,浮游植物群落组成季节差异显著.冗余分析表明,浮游植物群落的主要影响因子为营养盐、悬浮物、盐度和COD.结合历史数据分析表明,浮游植物优势种由硅藻占主要优势演替为硅藻和甲藻联合占优势.营养盐结构已有较大变化:硝酸盐浓度急剧升高,由20世纪80年代的1.30μmol/dm^3升至2014~2015年的24.58μmol/dm^3;磷酸盐浓度也由20世纪80年代的0.19μmol/dm^3升至2014~2015年的0.48μmol/dm^3;N/P由8.3升高至91.9.

This paper presents the seasonal community composition of net-collected phytoplankton near the sea area of Lianyungang. The samples were collected in January（ winter）,April（ spring）,August（ summer） and November（ autumn） in 2014 2015. A total of 8 phyla,68 genera,and 155 species were recorded including 115 diatom species and 30 dinoflagellate species,and other rare species such as Euglenophyta,Chrysophyta,Cryphophyta,Cyanophyta,Chlorophyta and Xanthophyta. The phytoplankton abundances in winter（ 230. 13 × 104cells/m3） was significantly higher than those in spring（ 24. 67 × 104cells/m3）,summer（ 119. 78 × 104cells/m3） and autumn（ 90. 25 × 104cells/m3）. Chaetoceros densus,Skeletonema costatum,Prorocentrum triestinum,C. castracanei,and Leptocylindrus minimus were the main dominant species. Both the phytoplankton community parameters（ abundance,species number,Shannon-Wiener diversity,Pielou evenness,and Margalef richness index） and the environmental variables（ temperature,salinity,p H value,DO,suspended solids,COD,DIN,and PO43--P levels） are seasonally different. The seasonal and spatial distributions of net-collected phytoplankton community are significantly different according to the results of cluster,multidimensional scaling and similarity analysis. Redundancy analysis shows that nutrition（ DIN and PO43--P）,salinity,DO,and COD are the main factors influencing phytoplankton community in turn. Since 1980 s,the environmental factors in the study area had changed obviously： concentrations of NO3--N dramatically increased from 1. 30 μmol/dm3 in 1983 1984 to 24. 58 μmol/dm3 in 2014 2015; and N∶ P ratio also increased from 8. 3 in 1983 1984 to 91. 9 in 2014 2015. The community structure has also experienced variation since 1980 s. Combined with the historical data,we found that the dominant species of phytoplankton are shifting from diatoms alone to dinoflagellates and diatoms.