2009年夏季南海北部的浮游植物群落

Phytoplankton community in the northern area of South China Sea in summer of 2009

根据2009年8月份对南海北部（1°～22N°，110°～117°E）水域22个采水站位的调查，分析夏季调查区浮游植物的群落结构特征。通过Uterm6hl方法共鉴定出浮游植物5门60属109种f不包括未定种），群落组成以硅藻为主，其次是甲藻。浮游植物生态类群以广温广布型种为主，调查区的优势种为柔弱伪菱形藻Pseudo—nitzschiadelicatissma，菱形海线藻Thalassionemanitzschioides，颗粒直链藻Melosiragrannulata，尖刺伪菱形藻Pseudo—nitzschiapungens，矮小短棘藻Detonulapumila，原多甲藻Protoperidiniumsp．，以及冰河拟星杆藻Asterionopsisglacialis。调查区细胞丰度介于0．009x100个／L到249．930×10。个／L，平均8．197×10。个／L。南海北部表层浮游植物细胞丰度由近岸向外海逐渐降低，高值区位于珠江口附近以及南部水域，甲藻在广东沿岸附近出现高值。调查区浮游植物丰度在垂直方向随着水深的增加而递减。Shannon．Wiener多样性指数和Pielou均匀度指数在珠江口南部和广东沿岸站住出现低值区，群落结构稳定性较差。

In this paper, phytoplankton samples were taken from the northern area of South China Sea （18°-22°N, 110°-117°E） in August 2009, and the phytoplankton species composition, community structure, diversity and its spatial distribution were reported. A total of 5 phyla 60 genera and 109 taxa were identified according the Uterm6hl method in the survey area. And the major groups were diatom and dinoflagellate. Most of the phytoplankton eco- types were temperate coastal species, while the warm-water species and oceanic species were rarely presented. The dominant species in the survey area were Pseudo-nitzschia delicatissma, Thalassionerna nitzschioides, Melosira grannulata, Pseudo-nitzschia pungens, Detonula pumila, Protoperidinium sp., and Asterionopsis glacialis. The cell abundance of phytoplankton ranged from 0.009× 10^3 to 249.930× 10^3cell/L, with an average of 8.197× 10^3cell/L. The highest cell abundance in surface layer was found in the Pearl River Estuary and southern part of the survey area. The high cell abundance of dinoflagellates was found in the coastal seawater of Guangdong Province. Vertically, the phytoplankton cell abundance were concentrated in surface water and decreased rapidly down to the bottom. The low values of Shannon-Wiener index and Pielou＇s evenness index were found in the southern Pearl River Estuary and the coastal water of Guangdong Province, indicating the rapid development of phytoplankton community.