1999年夏季南海北部和北部湾海域粒度分级叶绿素a和初级生产力的分布特征

DISTRIBUTION CHARACTERISTICS OF SIZE-FRACTIONATED CHLOROPHYLL A AND PRODUCTIVITY OF PHYTOPLANKTON IN THE NORTHERN SOUTH CHINA SEA AND BEIBU GULF DURING AUGUST 1999

南海是一个半封闭的边缘海,与中国和东南亚大陆相毗连。以往对南海海域物理海洋学的研究较多,对浮游植物生物量和生产力的研究较少,且大多研究均集中于西沙和南沙群岛(杨嘉东,1993;陈兴群等,1989),对南海北部海域的研究较少(黄良民,1992)。

The distribution of the abundance of phytoplankton, chlorophyll a concentration and primary productivity in the northern South China Sea and the Beibu Gulf were observed in August, 1999. The results showed that there were marked features of spatial zonation in the surveyed area due to the differences between the geographic environment and the hydrological conditions. Chlorophyll a value were higher near the Zhujiang (Pearl) River and lower near the eastern Hainan Island and southeastern Hong Kong at the northern South China Sea. Chlorophyll a in the surface decreased from nearshore to the mouth of the Beibu Gulf and the mean value in the water column were low at the center and mouth of the Beibu Gulf. The average concentration of chlorophyll a , primary productivity , and abundance of phytoplankton in the northern South China Sea and the Beibu Gulf were (2.03±1.18) and (0.69±0.39) mg/m3, 88.7 and 233.7 mgC/(m2·d), 0. 38 × 106- 1233.18 ×106 and 2. 10 × 106 - 47. 88 × 106 cell/m3, respectively. The results of the size-fractionation showed that the contribution of picoplankton (< 2μm) to total chlorophyll a and total primary productivity were in dominant position in phytoplankton community biomass and production of the northern South China Sea and Beibu Gulf. Nanoplankton (2-20μm) were less, and netplankton (>20μm) the least.