中文摘要：

于2011年12月至2012年11月采集了大亚湾海域9个站位表层水样,对大亚湾海域的浮游植物群落结构进行了周年调查。本次调查共鉴定出浮游植物93种,其中硅藻门40属55种,甲藻14属33种。秋季浮游植物种类较为丰富,春季和夏季较低。浮游植物细胞密度为41-396个/mL,年平均值为72.5个/mL。浮游植物细胞密度夏季较高,春季较低。硅藻是浮游植物优势类群,年均占浮游植物总细胞密度的83.6%,优势硅藻主要有拟菱形藻（Pseudo-nitzschia spp.）、丹麦细柱藻（Leptocylindrus danicus）、中肋骨条藻（Skeletonema costatum）等。甲藻细胞密度一般较低,各季节甲藻的百分比含量为1.5%-32.6%,春季血红哈卡藻（Akashiwo sanguinea）大量出现,最大细胞密度高达82.3个/m L。浮游植物种类多样性指数（H′）和均匀度（J）在冬季和秋季较高,夏季较低;远岸站点较高,近岸站点较低。研究结果说明虽然大亚湾浮游植物群落结构仍以硅藻占据优势,但甲藻种类与数量及百分比具有明显上升的趋势,同时近岸海域的富营养化导致了浮游植物种类多样性的下降。

英文摘要：

An annual survey of the phytoplankton community was conducted at nine stations in Daya Bay in the South China Sea between December 2011 and November 2012. A total of 93 taxa were identified in this survey, in which 55 taxa of 40 genera were diatoms and 33 taxa of 14 genera were dinoflagellates. Species numbers were higher in autumn and lower in spring and summer. Cell densities ranged between 41 and 396 cells/m L, with the annual mean being 72.5 cells/m L. Cell densities were higher in summer and lower in spring. Diatioms dominated the phytoplankton community, which contributed 83.6% to the total phytoplankton average. The predominant diatoms included Pseudo-nitzschia spp., Leptocylindrus danicus, and Skeletonema costatum ect. Dinoflagellates generally occurred in low numbers, with seasonal average proportions of approximately 1.5% to 32.6%. However, high densities of Akashiwo sanguinea were recorded in spring samples, with amaximum cell number of 82.3 cells/m L. The Shannon–Weaver species diversity index（H′） and Pielou＇s evenness（J） were higher in winter and autumn and lower in summer. H′ and J values were higher in the offshore stations and lower in the inshore stations. These results suggest that both species and cell numbers of dinoflagellates have been clearly increased in Daya Bay, though the phytoplankton community is dominated by diatoms up till now. The high nutrient levels in the inshore areas resulted in a decrease of the species diversity of phytoplankton.