中文摘要：

根据2013年5月的大面调查资料,对三门湾海域网采浮游植物的群落特征进行了初步研究。调查海域共检出浮游植物9门253种,以硅藻为主,占总种数的71.5%,其次是甲藻,占总种数的16.6%,其余藻类所占比率较低。浮游植物细胞丰度平均值为（2 227±3 883）×103个/m3,高值区分布在湾口东北部。优势种主要有短角弯角藻Eucampia zoodiacus、中华盒形藻Biddulphia sinensis、卡氏角毛藻Chaetoceros castracanei、整齐圆筛藻Coscinodiscus concinnus、中肋骨条藻Skeletonema costatum、琼氏圆筛藻Coscinodiscus jonesianus和弯菱形藻Nitzschia sigma。受水温和盐度等环境因素的影响,浮游植物优势种在湾口、湾中和湾顶部形成区域分布差异。对比历史资料可知,该海域网采浮游植物细胞丰度增加,而硅藻占总种数百分比则呈下降趋势。

英文摘要：

Based on the survey in Sanmen Bay in May 2013,apreliminary research on the net-phytoplankton community characteristics was carried out.The results show that a total of 9 phyla’ 253 species are found in the survey area,and the community is mainly composed of Bacillariophyta（71.5%）,followed by Dinophyta（16.6%）,and other phyla occupy low ratio.The average value of cell abundance is（2 227±3 883）×103个/m3,and the highest value appears in the northeastern area near the mouth of the bay.The dominant species are Eucampia zoodiacus, Biddulphia sinensis, Chaetoceros castracanei, Coscinodiscus concinnus,Skeletonema costatum,Coscinodiscus jonesianus and Nitzschia sigma. Because the effect of water temperature,salinity or other environmental factors,the dominant species distribution demonstrates spatial difference among the mouth,the middle and the top of the bay.Besides,comparing with the historical data,it is find that the phytoplankton cell abundance increases and the diatom species declines in percentage of the total species.