中文摘要：

作者基于2011年9月（丰水期）和2012年1月（枯水期）粤西近岸30米以浅海域的调查资料，分析该海域浮游植物的种类组成、优势种、丰度及其群落结构多样性。结果表明，调查海域共鉴定浮游植物4门41属116种，硅藻为最主要优势类群。丰水期与枯水期共有种类40种，物种相似性指数为34.48%，表明2个调查季节种类组成变化较大，存在明显的季节性差异。枯水期优势种仅1种，为金藻门（Chrysophyta）的球形棕囊藻（Phaeoecystis globosa），优势度高达0.496；丰水期优势种有4种，其中以硅藻门的旋链角毛藻（Chaetoceros curvisetus）优势度较高（0.249）。浮游植物丰度表现出时间和空间异质性，丰度总体呈现近岸站位高于离岸站位，此外，丰水期浮游植物丰度湛江沿岸站位高于其他调查站位，枯水期浮游植物丰度则由西南部向东北部递减，总体而言，枯水期浮游植物丰度比丰水期高。群落结构多样性为枯水期西南部海域明显低于东北部海域，丰水期站位间多样性无明显变化规律，相比之下，丰水期群落物种多样性水平相对较高。相关分析表明：浮游植物丰度与 pH、悬浮物呈正相关，与丰水期水温和枯水期盐度呈负相关。

英文摘要：

Based on data collected during an ecological investigation of West Guangdong before 30 meters coastal waters during a wet （September 2011） and a dry season （January 2012）, the species composition, dominant species, abundance, and community diversity of phytoplankton were analyzed. A total of 116 species consisting of 41 genera belonging to 4 phyla were identified. Diatom was the predominant phyla group. Forty common species occurred in both wet and dry seasons, with a species similarity index between the two seasons of 34.48% suggesting significant seasonal variation in the species composition. Only one dominant species occurred during the dry season,Phaeo-cystis globosa, with a dominance of 0.496. During the wet season, there were four dominant species, the main one wasChaetoceros curvisetus with a dominance of 0.249. Phytoplankton abundance showed significant seasonal and regional differences and was higher in inshore waters than in offshore. During the wet season, the phytoplankton abundance in the Zhanjiang coastal waters was the highest. During the dry season, phytoplankton abundance de-creased from the southwest to northeast coastal waters. In general, the phytoplankton abundance during the dry season was higher than during the wet season. Community diversity indexes in the southwest waters during dry season were obviously lower than those in the northeast waters. Diversity indexes during the wet season were rela-tively higher than during the dry season, but there were no significant differences in diversity during the wet season. Correlation analysis demonstrated that the phytoplankton abundance was positively correlated to pH and suspended solids （SS）, and negatively correlated to water temperature during the wet season and salinity during the dry season.