舟山群岛海域网采浮游植物分布与多样性

Distribution and diversityof net-collected phytoplankton in the waters nearbyZhoushan Islands

于2014年夏、秋两季在舟山海域进行了浮游植物拖网采集和环境理化因子测定,共鉴定浮游植物6门92属184种,其中硅藻门127种,甲藻门30种,为调查海域主要浮游植物类群。夏季骨条藻Skeletonemaspp.为绝对优势种,秋季优势种由琼氏圆筛藻Coscinodiscus jonesianus、虹彩圆筛藻Coscinodiscus oculus-iridis、蛇目圆筛藻Coscinodiscus argus、星脐圆筛藻Coscinodiscus asteromphalus、骨条藻Skeletonemaspp.、尖刺伪菱形藻Pseudo-nitzschia pungens、并基角毛藻Chaetoceros decipiens、伏氏海毛藻Thalassiothrix frauenfeldii及中间肋缝藻Frustulia interposita等9种硅藻构成。调查海域夏季浮游植物平均丰度(1 713.58×104个/m3)高于秋季(1 430.30×104个/m3)。冗余分析表明,温度、盐度、悬浮物、溶解无机磷及溶解无机氮等环境因子对夏、秋两季浮游植物群落影响较大。结合历史数据分析可知,舟山海域近30a来富营养化程度严重且日益加剧,富营养化指数明显升高;同时浮游植物群落变化也十分显著,主要体现为细胞丰度增加和优势种更替。

The net-collected phytoplankton community and physicochemical properties of the waters nearby Zhoushan Islands during summer and autumn of 2014 were investigated.A total of 6phyla,including 92 genera and 184 species were indentified,of which 127 diatom and 30 dinoflagellat species were found in this survey area.The species Skeletonema spp.is dominant in summer,while the dominant species in autumn consists of nine diatom species（i.e.,Coscinodiscus jonesianus,Coscinodiscus oculus-iridis,Coscinodiscus argus,Coscinodiscus asteromphalus,Skeletonema spp.,Pseudo-nitzschia pungens,Chaetoceros decipiens,Thalassiothrix frauenfeldii and Frustulia interposita）.The phytoplankton abundance in summer（1 713.58×10^4ind/m3）is higher than that in autumn（1 430.30×10^4ind/m3）.According to the results of Redundancy Analysis,the temperature,salinity,suspended particulate matter,dissolved inorganic phosphorus and nitrogen are the main environmental factors affected on the phytoplankton community in summer and autumn.Based on the analysis of the integrated historical data,the eutrophication index at the research area has increased clearly since 1996,and the structure of phytoplankton community has also changed significantly.It reflects on the cells abundance increase and the dominant species substitution.