夏季北冰洋楚科奇海微微型、微型浮游植物和细菌的丰度分布特征及其与水团的关系

本文利用2008年我国第三次北极科学考察的机会，分析了夏季楚科奇海微微型、微型浮游植物和细菌丰度的分布特征，并探讨了它们与楚科奇海水团之间的关系。结果表明：与北冰洋的其它海域相比，楚科奇海的微型浮游植物丰度相对较高（0.03~10.23×103 cells/mL），微微型浮游植物则大致相同（0.01~2.21×103 cells/mL），而浮游细菌丰度明显较高（0.21~9.61×106 cells/mL）。白令海陆架水与海冰融化混合水和阿纳德尔水浮游植物群落结构不同，夏季随着太平洋水入流水对楚科奇海的日益影响，其水体本身的群落结构可能被外来群落替代。

SPATIAL DISTRIBUTION OF PICO- AND NANO- PHYTOPLANKTON AND BACTERIA IN THE CHUKCHI SEA IN RALATION TO WATER MASSES

Based on the Third Chinese Arctic Expedition cruise in the summer of 2008, the distribution patterns of pico-, nano-plankton and bacteria abundance in the Chukchi Sea were studied. Pico- and nano-phytoplankton abundances ranged from 0.01×103 to 5.51×103 cells/mL and from 0.01×103 to 5.51×103 cells/mL, respectively. The lowest numbers of bacteria in the entire water column was recorded at station R17 at 100 m depth (0.21×106 cells/mL), and the highest concentration was observed at station R09 at 10 m depth (9.61×106 cells/mL). Our results demonstrated that melting sea ice is affecting affects the physical characteristics of the Chukchi Sea by causing reductions in the salinity of the surface mixed layer, which in turn results in greater hydrodynamic stability of the water column. These changes were accompanied by increasing bacterial concentrations. The Pacific warm water brought high nutrients into the Chukchi Sea, which led to higher abundance of bacteria and nano-phytoplankton in the Chukchi Sea comparing to other regions of the Arctic Ocean. However, the number of picophytoplankton in the Anadyr Water with notably relation to chlorophyll a was larger than the other two water masses. The structure of pico- and nanoplankton communities coupled with the water masses in the Chukchi Sea was can be considered to act as asindicators of the variability the inflow of Pacific warm water into the Chukchi Sea.