东海聚球蓝细菌(Synechococcus)的分布特点及在微食物环中的作用

DISTRIBUTION OF SYNECHOCOCCUS AND ITS ROLE IN THE MICROBIAL FOOD LOOP IN THE EAST CHINA SEA

利用荧光显微镜技术研究了东海 ( 2 7°— 32°N ,1 2 2°— 1 30°E)中聚球蓝细菌 (Syne chococcus)的数量。结果表明 ,冬季 ( 1 997年 2— 3月 )聚球蓝细菌生物量是 7.2 1— 0 0 1 1mgC/m3(平均为 0 82mgC/m3) ,夏季 ( 1 998年 7月 )聚球蓝细菌生物量是 5 78— 0 1 9mgC/m3(平均为1 43mgC/m3)。夏季聚球蓝细菌的平均值是冬季的 1 7倍。冬季受黑潮水的影响 2 0m层和表层中的聚球蓝细菌数量自东南向西北递减。聚球蓝细菌生物量在总浮游植物生物量 (CB/PB)中占的比例冬季平均是 1 0 % ( 0 5 %— 91 8% ) ,夏季平均是 3% ( 0 6%— 1 0 6% ) ,冬季是夏季的 3 3倍。微型浮游动物 (nanozooplankton)是东海聚球蓝细菌的主要捕食者 ,对聚球蓝细菌捕食率为 0 2 1 8— 0 75 9/d。

In the East China Sea was measured by epifluorescence microscopy in winter (Feb —Mar , 1997) and summer (July, 1998) Cyanobacterial biomass (CB) varied from 7 21—0 011mgC/m 3 (mean = 0 82mgC/m 3) in the winter and 5 78—0 19mgC/m 3 (mean = 1 43mgC/m 3) in the summer The average of CB was higher in summer than that in winter CB decreased from southeast to northwest in the surface and 20m in winter Kuroshio water was an important factor that affects the horizontal distribution of CB in winter The ratio of cyanobacterial biomass to phytoplankton biomass (CB/PB) was 0 05—0 92 (mean = 0 10) in winter and 0 06—0 11 (mean = 0 03) in summer The high value of CB/PB was in mesotrophic and oligotrophic waters (<5μmol/L NO 3) Experimental investigations showed that cyanobacterial population was grazed by nanozooplankton in the East China Sea Grazing rates varied between 0 218—0 759/d in summer