南大洋和南极考察航线海表超微型浮游生物分布及影响因子

南极考察航线跨越全球多个大洋，对认识超微型浮游生物在全球尺度分布及变化具有重要意义。依托中国第33次南极考察，利用流式细胞仪对航线海表水样中的超微型浮游生物进行了现场测定。结果表明，在热带与温带海域，超微型浮游生物量可占总叶绿素a浓度的60%以上，在南大洋则集中在15%～40%；原绿球藻主要分布在40°S以北海域，聚球藻主要分布在50°S以北海域，而超微型真核藻类和异养细菌则在沿线各海域均有明显分布。在纬向上，原绿球藻、聚球藻、超微型真核藻类和异养细菌的平均丰度分别为(5.50±9.09)×10³ cells/mL、(13.56±20.33)×10³ cells/mL、(3.87±3.08)×10³ cells/mL和(6.39±4.78)×10⁵ cells/mL；南大洋海域，超微型真核藻类和异养细菌的平均丰度分别为(3.31±1.46)×10³ cells/mL和(4.68±4.39)×10⁵ cells/mL，在少数站位检测到较低丰度的聚球藻，平均值...

Distribution and environmental impact factors of ultraplankton abundance in the surface water of the Southern Ocean and Antarctic cruise routes

The Antarctic cruise routes across different regions of the global oceans, it is of great significance to understand the global distribution of ultraplankton. During 33rd Chinese Antarctic Expedition, we used flow cytometry to investigate large-scale latitudinal distribution of ultraplankton abundance and its effect factors in the surface water along the cruise routes. The results showed that picoplankton accounted for 60% of total chlorophyll a (Chl a) concentration in the tropic and temperate zones and the contribution of picoplankton to total Chl a concentration varied from 15% to 40% in the Southern Ocean. Prochlorococcus (Pro) were mainly distributed in the north of 40°S, Synechococcus (Syn) were distributed in the north of 50°S, while pico-eukaryotes (PEuk) and heterotrophic bacteria (HBac) were detected and distributed in the Southern Ocean and along the cruise routes. The average abundance of Pro, Syn, PEuk and HBac were (5.50±9.09)×103 cells/mL, (13.56±20.33)×103 cells/mL, (3.87± 3.08)×103 cells/mL and (6.39±4.78)×105 cells/mL respectively on the latitudinal routes. The average abundance of PEuk and HBac were (3.31±1.46)×103 cells/mL and (4.68±4.39)×105 cells/mL in the Southern Ocean. Syn cells were detected in a few stations of the Antarctic waters, the average abundance was (0.38±0.39)×103 cells/mL. The results of environmental factor correlation analysis showed that there was a distinct negative correlation between PEuk abundance and temperature, and a distinct positive correlation between Pro abundance and temperature. Salinity and nutrients did not have obvious influence on the distribution of ultraplankton along the latitudinal. There was a close negative correlation between ultraplankton abundance and nutrients in the Southern Ocean. Nitrate, phosphate and silicate were important factors in the Antarctic Peninsula. Nitrate and phosphate were main environmental factors in the Ross Sea.