南大洋环极表层水浮游植物分级生物量、初级生产力和颗粒有机碳的分布

198 9/1 990年夏季作者在中国第六次南极考察环极航行中 ,对南大洋不同海区的浮游植物细胞大小分级叶绿素 a和初级生产力、颗粒有机碳及有关环境参数进行了测定。结果表明 ,在南极水域中以南大西洋最为肥沃 ,叶绿素 a浓度平均超过 2 μg/dm3 ,POC的平均浓度也最高 (>1 0 0 μg/dm3 ) ,而德雷克海峡和南印度洋较低。叶绿素 a和 POC的空间变异具有同步的波动。分级叶绿素 a结果表明 ,在肥沃的南大西洋以细胞 >2 0 μm的绢滤浮游生物 (主要是小型浮游生物 )所占比重最高 (6 5 %) ,而在较贫瘠的南印度洋则以微微型浮游生物 (<2 μm)最高 (47%)。分级初级生产力的结果表明 ,在南大西洋和德雷克海峡对总初级生产力的贡献以微微型浮游生物为最大 ,微型浮游生物和小型浮游生物的贡献大致相当。微微型浮游生物相对高的光合作用生理活性显示了它们在南大洋海洋生态系中的重要性。与南极水域相比 ,亚南极和亚热带水域较为贫瘠。

SIZE-FRACTIONATED BIOMASS AND PRODUCTIVITY OF PHYTOPLANKTON AND PARTICULATE ORGANIC CARBON IN THE SURFACE ON THE ROUTINE ENCIRCLING THE ANTARCTICA

During the austral summer of 1989/1990,cell size-fractionated biomass and productivity of phytoplankton,particulate organic carbon(POC) and the relevant environmental parameters in the surface of a large scale sea area encircling the Antarctic continent were observed.The results showed that,in the Antarctic waters,the Southern Atlantic Ocean is the most fertile,chlorophyll a concentration averaged over 2 μg/dm 3;average POC concentration was also the highest (>100μg/dm 3),while being lower in the Drake Passage and the Southern Indian Ocean.The results of size-fractionated chlorophyll a showed that netplankton with cell >20μm in the Southern Atlantic Ocean having abundant nutrients accounted for the highest proportion(65%),while in infertile Southern Indian Ocean,picoplankton accounted for the highest proportion,for example,averagely accounting for 47% in the Southern Indian Ocean.The results of size-fractionated productivity showed that the contribution of picoplankton to total productivity was the largest in the Southern Atlantic ocean and Drake Passage,that of nanoplankton and netplankton were approximate.The relative high photosynthesis assimilation number of picoplankton menifests their importance in marine ecosystems of the Antarctic water.In comparison with the Antarctic water,the Subantarctic and Subtropical waters are infertile.