1999/2000年夏季环南极表层海水叶绿素a和初级生产力

中国第 1 6次南极考察期间 ,作者随雪龙船于 1 999年 1 1月 2 2日至 2 0 0 0年 1月 1 8日从澳洲西南部到达东南极普里兹湾 ,后经南印度洋 -南大西洋 -德雷克海峡 -南大西洋 -南印度洋返回普里兹湾。航渡中定时采集表层海水 ,进行水温、盐度、营养盐、浮游生物现存量和光合作用速率的现场观测 ,研究环绕南极海域表层水叶绿素 a和初级生产力的分布特征。结果表明 ,南大洋表层水营养物质、浮游生物现存量和初级生产力分布具明显的区域性特征 ,南极辐合带以南的南极水营养盐浓度高于亚南极水和亚热带水。叶绿素 a浓度与营养物质的分布趋势一致 ,南极水、亚南极水和亚热带水的平均叶绿素 a浓度分别为 1 .77、1 .40和 0 .2 1 μg/dm3。在环绕南极的大洋中 ,南大西洋海域营养物质丰富 ,海水最为肥沃 ,叶绿素 a浓度和初级生产力高于南印度洋和德雷克海峡。在短期往返东南极 -西南极 -东南极的航渡观测中 ,由于南极夏季水温的升高 ,陆缘冰融化 ,冰藻释放 ,长城湾至普里兹湾的西 -东向航渡中观测的初级生产力、浮游植物细胞丰度、叶绿素 a浓度和光合作用同化数分别比普里兹湾至长城湾的东 -西向航渡中高 1 45%、1 1 3%、68%和 1 8%。与 1 0年前的观测结果比较 ,南大西洋仍为高生物量和高生产力海区 ;1 999/2 0 0 0

PRIMARY PRODUCTIVITY AND CHLOROPHYLL A IN THE SURFACE WATER ON THE ROUTE ENCIRCLING THE ANTARCTICA DURING AUSTRAL SUMMER OF 1999/2000

WT5BZ]During the austral summer of 1999/2000 (CHINARE 16), the seawater temperature, salinity, nutrients, potential primary productivity and chlorophyll a of phytoplankton in the surface water were observed. That was a large scale sea area encircling the Southern Indian Ocean, Prydz Bay, the Southern Atlantic Ocean and the Drake Passage. The results showed that there was marked spatial feature in the sea areas surveyed. In the Antarctic surface water, temperature was lower, the nutrients and chlorophyll a were higher than the Subantarctic water and Subtropical water. The chlorophyll a were (1.77±1.48), (1.40±0.14), (0.21±0.09)μg·dm -3 in the Antarctic, Subantarctic and Subtropical surface water, separately. In the Antarctic water, the Southern Atlantic Ocean is the most fertile, where chlorophyll a concentration and potential primary productivity were more than those in the Drake Passage and the Southern Indian Ocean. Because the temperature rose, floe ice melted and ice algae were released into the seawater, the biological parameters observed from the Great Wall Bay to the Prydz Bay at austral summer were higher than that from the Prydz Bay to the Great Wall Bay at early summer. It is still a sea area with high biomass and high productivity in the Southern Atlantic Ocean according to the result observed during CHINARE VI, IX; the value of primary productivity from the Great Wall Bay to Prydz Bay and chlorophyll a in the Southern Indian Ocean in 1999/2000 were obviously higher than that in former years, this might relate to that the survey stations were in the high latitude region and some stations lied in the polynya. [WT5HZ]