1998/1999年南极夏季普里兹湾及北部海区叶绿素a和初级生产力的分布特征

THE DISTRIBUTION FEATURE OF CHLOROPHYLL A AND PRIMARY PRODUCTIVITY IN PRYDZ BAY AND ITS NORTH SEA AREA DURING THE AUSTRAL SUMMER OF 1998/1999

1998 /1 999年南极夏季 ,作者随“雪龙船”在南极普里兹湾及其北部海区 (63° - 69°1 2′S ,70°30′- 75°30′E) 3条断面 2 4个测站进行浮游生物现存量和初级生产力的现场观测 ,研究叶绿素a浓度和初级生产力的分布特征。测区表层叶绿素a浓度为 0 .1 6 - 3 .99μg/dm3,普里兹湾内和湾西部四女士浅滩海域浓度在 3 .5μg/dm3以上 ;平面分布趋势从湾内向西北方向递减 ,深海区浓度在 0 .5μg/dm3以下。从垂向看叶绿素a浓度的最大值大多出现于 2 5m或 50m层 ,50m以下更深层的浓度随深度的增加而降低 ,2 0 0m层叶绿素a浓度分布范围为 0 .0 1 - 0 .95μg/dm3。粒径分级叶绿素a浓度以微小型浮游生物的贡献占优势 (56 % ) ,微型浮游生物的贡献占2 4 % ,微微型浮游生物的贡献占 2 0 %。测区潜在初级生产力为 0 .1 1～ 1 1 .67mgC/(m3·h) ,平均值为 2 .0 0± 2 .80mgC/(m3·h)。高生产力区位于普里兹湾 ,平均现场生产力达到 0 .86gC/(m2 ·d) ;依次为陆架区、陆坡区 ,深海区生产力较低 ,平均现场生产力为 0 .1 7gC/(m2 ·d)。光合作用同化数较低 (1 .53± 1 .1 1mgC/(mgChla·h) )。粒径分级初级生产力以微小型浮游生物的贡献占优势 (58% ) ,微型浮游生物的贡献占 2 6 % ,微微型浮游生物的贡献占 1 6 %。浮游植?

The investigation of chlorophyll a and primary productivity were carried out in three longitudinal sections (70°30′E, 73°00′E and 75°30′E) at December 18-26,1998 and January 12 -18, 1999 in Prydz Bay and its north sea area. The results showed that surface chlorophyll a concentration were 0.16-3.99 μg/dm 3 . The high value of chlorophyll a concentration (more than 3.5 μg/dm 3 ) was in the bay and West Four Ladies Bank. The average chlorophyll a concentration at sub surface layer (25m) was higher than that at surface layer; its concentration at the deeper layers of over 50m decreased with increasing depth and that at 200m depth was only 0.01-0.95 μg/dm 3 . The results of size frationated chlorophyll a showed that the average contribution of netplankton to total chlorophyll a in surveyed area was 56%, those of nanoplankton and picoplankton were 24% and 20% respectively. The potential primary productivity at euphotic layer in investigated area was 0.11-11.67mgC/(m 3 ·h) and average value was 2.00±2.80 mgC/(m 3 ·h). The in situ productivity in the bay and continental shelf was higher and that in deep sea area was lower. The assimilation number of photosynthesis was 1.53±1.11 mgC/(mg Chl a ·h). The results of size frationated primary productivity showed that the average contribution of netplankton to total productivity in surveyed area was 58%, those of nanoplankton and picoplankton were 26% and 16% respectively. The cell abundance of phytoplankton was 1.6×10 3 -164.8×10 3 cell/dm 3 .