2009年冬季南海北部网采浮游植物群落结构

Community structure of netz-phytoplankton in northern South China Sea in winter, 2009

根据2010年1月6～30日对南海北部的调查取样，作者对该海域网采浮游植物的分布和群落结构特征等进行了分析。共鉴定浮游植物4门52属155种（包括变形及变种），主要以温带近岸和广布性种为主，其中硅藻有38属94种，占总种数的60．6％；甲藻有12属58种，占总种数的37．4％；浮游植物平均细胞丰度为36．46×10^4个／m^3，硅藻平均细胞丰度为13．77×10^4个／m^3，甲藻平均细胞丰度为1．39×10^4个／m^3，铁氏束毛藻（Trichodesmium thiebautii）平均细胞丰度为21．30×10^4个／m^3。粤东近岸区域是浮游植物高密集区，珠江口及其西南沿岸其次，而浮游植物稀疏区主要在调查区的中部海域，呈现出沿远岸区域逐渐降低的平面分布格局。除铁氏束毛藻为绝对优势种外，主要优势种有：菱形海线藻（Thalassionema nitzschioides）、短刺角毛藻（Chaetoceros messanensis）、圆筛藻（Coscinodiscus spp．）、粗根管藻（Rhizosolenia robusta）及角毛藻（Chaetoceros spp．）等。浮游植物群落香农．威纳物种多样性指数（H’）平均值为4．50，Peilou均匀度指数（J）平均值为0．81。浮游植物多样性程度较高，与细胞丰度平面分布基本呈相嵌分布，仅在近岸出现低值。

Based on the cruise in northern South China Sea （SCS） from 6th January to 30th, 2010, we analyzed the characteristics of netz-phytoplankton distribution and community structure in this area. The majority of species ecotype were neritic and cosmopolitan in temperate coastal seas. One hundred and fifty-fie species were identified （including variety and form） belonging to 4 phyla with 52 genera, in which 60.6% were diatoms （38 genera and 94 species） and 37.4% were dinoflagellates （12 genera and 58 species）. The average cell abundance of phytoplankton Bacllariophyta or Pyrrophyta was 36.46× 10^4cells/m^3, 13.77× 10^4cells/m^3 or 1.39× 10^4cells/m^3, respectively. In addition, the average cell abundance of Trichodesmium thiebautii was 21.30× 10^4cells/m^3. It was found that the coastal water of Eastern Guangdong was the area of highest phytoplankton abundance, followed by the Pearl River estuary and the coastal waters southwestward. Phytoplankton abundance decreasing from coastal area to far-shore area, the central area of the northern South China Sea was the area of lowest phytoplankton abundance. The dominant species included Thalassionema nitzschioides, Chaetoceros messanensis, Coscinodiscus spp., Rhizosolenia robusta, and Chaetoceros spp. besides Trichodesmium thiebautii. The average diversity index （H＇） and evenness （J） values were 4.50 and 0.81, respectively. The diversity level of phytoplankton community in survey area was high, the horizontal distribution of diversity index was contrary to phytoplankton cell abundance, with a low area in the inshore area.