2005年夏末渤海网采浮游植物群落结构

The Net-phytoplankton Community Structure of the Bohai Sea in Late Summer,2005

利用2005年8月渤海4个断面共计42站位的综合外业调查所获资料，分析了浮游植物群落的结构特征。调查共鉴定出浮游植物5门48属114种．其中硅藻31属81种，甲藻13属29种，金藻1属1种．绿藻1属1种，裸藻1属1种（未鉴定到种），还包括1种分类地位不明确的三裂醉藻。渤海各近岸水域的浮游植物物种的分布具有较为明显的分散性，优势种多为硅藻，主要有中肋骨条藻、拟旋链角毛藻、菱形海线藻和旋链角毛藻；甲藻中又角藻成为优势种。与历史资料比较发现主要优势种发生了演替现象。浮游植物细胞丰度值为5．4×10^4～23843．8×10^4个／m^3，平均为1083．4×10^4个／m^3，与同期历史资料相比，细胞丰度值较往年偏高；各调查断面细胞丰度值大小依次为秦皇岛附近海域〉辽东湾〉黄河口附近海域〉渤海湾。香农-威纳指数为0．54～4．18，平均为2．60，渤海湾和秦皇岛附近海域处于较高的多样性水平．而黄河口附近海域次之，辽东湾最低。另外，网采浮游植物群落的多样性随细胞丰度值的对数增加而降低；

Features of phytoplankton community structure are analysed, using the data obtained during the comprehensive investigation at the 42 stations along the 4 sections in the Bohai Sea in later summer 2005. Totally 114 species of phytoplankton are found, which belong in 48 generas of 5 phylas, and there are 81 species of diatom in 31 generas, 29 species of pyrrophyta in 13 generas, 1 species of chrysophyta in 1 genera, 1 species of chlorophyta in 1 genera, and 1 species （undetermined） of euglenophyta in 1 genera. There is also 1 species of ebria tripartitus which systematic status is undetermined. The species compositions in the near-shore waters of the Bohai Sea are not identical but the dominant species are of diatom such as skeletonema costatum, chaetoceros pseudocurvisetus, thalassionema nitzschioides, and chaetoceros curvisetus. Among phrrophyta, ceratium furca is dominant. It is found from comparison with historical data obtained in the same seasons that the dominant specics are changed in some area. Phytoplankton cell abundance ran- ges from 5.4× 10^4 to 23 843.8 × 10^4 cells/ma with an average about 1 083.4 ×10^4 cells/ma and becomes higher than that in the historical data of the same seasons. If the aundance depending upon locations in the survey area is put in an order from the high to the low, it follows that the waters adjacent to Qinhuangdao ）the Liaodong Bay）the Yellow River estuary）the Bohai Bay. The Shannon wiener index ranges from 0.54 to 4.18 with an average of 2.60. The biodiversity becomes higher in the Bohai Bay and the waters adjacent to Qinhuangdao, the next comes the Yellow River Estuary, and it becomes the lowest in the Liaodong Bay. The biodiversity of the net-phytoplankton community decreases with the increase of logrithm of the cell abundance value.