东印度洋南部春季网采浮游植物群落特征及长期变化

于2013年3月至5月采集了东印度洋南部（10.0°S－4.0°N，83.0°E－102.0°E）浮游植物样品，分析了其种类组成、生态类型、优势种类和细胞丰度等群落结构特征参数。为探寻全球气候变化影响下的热带印度洋浮游生态系统的长期变化，收集整理了该相近区域1960年、2016年的浮游植物数据，综合分析了其浮游植物种类组成和优势种的变化规律。结果表明:本研究共鉴定浮游植物4门350种（含变种、变型），其中，硅藻48属162种，甲藻24属183种，金藻2属4种。生态类型以热带外洋性种、暖水性种为主。优势种组成中硅藻种类占明显优势，如美丽漂流藻Planktoniella formoa、菱形藻Nitschia spp、角毛藻Chaetoceros spp.、佛朗梯形藻Climacodium frauenfeldianum和距端假管藻Pseudosolenia calcaravis，甲藻有夜光梨甲藻Pyrocystis noctiluca和波状新角藻Neoceratium trichoceors。细胞丰度分布不均，调查区东南部细胞丰度较高为140.3×103 cells/m3，低值区的细胞丰度多在103cells/m3，赤道临近水域在104 cells/m3。与60 a前相比，浮游植物种类总数、甲藻和硅藻种类数均有所上升，甲藻种类数均高于硅藻；几次研究均显示硅藻类群是东印度洋海域的优势类群，角毛藻属的优势种类明显增加。

Phytoplankton assemblage and their inter-annual variation in the south sector of Eastern Indian Ocean in spring

Phytoplankton net samples were collected in the south sector of Eastern Indian Ocean (10.0°S-4.0°N, 83.0°E-97.5°E) from March 13 to May 7, 2013.Phytoplankton community structure features were analyzed, including species composition, ecotypes, cell abundance, dominant species, and diversity.To understand the inter-annual variation of phytoplankton community under the context of climate change, we also compiled previous phytoplankton community data in the 1960s and 2013, and compared with present study.Of the 350 taxa (including variation, form and unidentified taxa), 162 taxa of 48 genera in Bacillariophyta, 183 taxa of 24 genera in Dinophyta and 4 taxa of 2 genera in Chrysophyta were recorded.The dominant phytoplankton ecotypes were tropical oceanic species and warm oceanic species.The dominant species were mostly Bacillariophyta, such as Planktoniella formoa, Nitschia spp.Chaetoceros spp., Climacodium frauenfeldianum and Pseudosolenia calcaravis, while the others belonged to Dinophyta (Pyrocystis noctiluca and Neoceratium trichoceors).The highest cell abundance of 140.3×103 cells/m3 were recorded in the southeast of surveyed area, and intermediate level of 104 cells/m3 were found around the equator.In the last 60 years, the taxa number of phytoplankton community, including both Bacillariphyta and Dinophyta, increased.Dinophyta had higher species number than Bacillariophyta.However, Bacillariophyta always dominated phytoplankton community in the Eastern Indian Ocean, and the number of dominant species belonging to Chaetoceros spp. increased remarkably in the last several decades.