西沙宣德群岛海域浮游植物群落及其影响因子

为了解西沙宣德群岛海域浮游植物群落结构特征，于2019年2月和11月对该海域进行采样调查，分析浮游植物群落组成及环境影响因素。两个航次共发现109种浮游植物，其中硅藻门最多，有81种。冬秋季节优势种不尽相同，冬季优势种为铁氏束毛藻(Trichodesmium thiebautii)、红海束毛藻(T. erythraeum)和标志星杆藻(Asterionella notata)等，秋季优势种为菱形海线藻(Thalassionema nitzschioides)、丹麦细柱藻(Leptocylindrus danicus)和劳氏角毛藻(Chaetoceros lorenzianus)。冬季浮游植物平均丰度[(5.27±6.14)×10⁷ cells/L]显著高于秋季[(1.56±1.40)×10⁵ cells/L]。浮游植物群落分布主要受亚硝酸盐、盐度等环境因子影响。冬秋季各站位浮游植物群落的多样性指数、均匀度指数和丰富度指数平均值分别为3.15、0.71、1.36和3.28、0.75、1.77。因此，宣德群岛海域冬秋季节浮游植物群落多样性较高，物...

Phytoplankton Community and Its Influencing Factors in Xuande Islands of Xisha Sea Area

In order to understand the characteristics of phytoplankton community structure in Xisha Xuande Islands, the phytoplankton community composition and environmental factors sampled in February and November 2019 were analyzed. The results showed that 109 species of phytoplankton were found during the two voyages, among which Bacillariophyta were the most with 81 species. The dominant species varied between winter and autumn, Trichodesmium thiebautii, T. erythraeum, Asterionella notata, etc. were the dominant in winter, and did Thalassionema nitzschioides, Leptous danicus and Chaetoceros lorenzianus were in autumn. The average abundance of phytoplankton in winter[(5.27±6.14)×10⁷ cells/L] was significantly higher than that in autumn[(1.56±1.40)×10⁵ cells/L]. The structure of phytoplankton community was mainly affected by nitrite, salinity and other environmental factors. The average of Shannon-Wiener diversity index (H''), Pielou evenness index (J'') and Margalef richness index (d'') in winter and autumn were 3.15, 0.71, 1.36 and 3.28, 0.75, 1.77, respectively. As a whole, these indicated that phytoplankton community in Xuande Islands had high diversity and rich species, as well as complex and stable community structure in winter and autumn.