2012年夏季北极浮冰生物群落结构及垂直分布特征研究

海冰生物群落是北极生态系统的重要组成部分，在北冰洋初级生产和碳循环中扮演着重要角色。本文利用荧光显微分析技术对2012年度夏季采集于北冰洋中心区的浮冰生物群落进行了分析，结果显示：柱总生物量平均为105.85±53.41 mgC ?m^-2，其中细菌占生物量的47.2%，而后依次是硅藻（26.7%），鞭毛虫（18.2%），鞭毛藻（6.9%）和纤毛虫（1.0%）。最高纬站位（123°43.454′E 87°39.598′N）出现冰底鞭毛藻藻华现象，生物量可达329.6 μg C?L^-1，该站位生物群落处于硅藻藻华后期，海冰上层存在较大程度的融冰作用，底部冰芯营养盐N/P比较高，可能形成有利于鞭毛藻生长的小生境。与已有研究结果的对比表明，近年来夏季北极海冰的快速融化对浮冰生物群落结构产生了明显影响，异养类群生物量升高，细菌取代硅藻成为优势类群。

PACK ICE COMMUNITY STRUCTURE IN THE ARCTIC OCEAN DURING SUMMER 2012

As a part of the Arctic Ocean ecosystem, the sea ice community plays important roles in primary production and the carbon cycle. In this study, we used the fluorescence microscopy technique to analyze samples of the pack ice community, collected from the central Arctic Ocean in summer 2012. The results showed that the average integrated biomass was （105.85±53.41） mg C?m^?2, of which heterotrophic bacteria comprised 47.2%, followed by diatoms (26.7%), heterotrophic flagellates (18.2%), autotrophic flagellates (6.9%), and ciliates (1.0%). An autotrophic flagellate bloom was observed at the bottom of the high-latitude station (87°39.598′N, 123°43.454′E). The community of this station was in the late period of diatom algal bloom and there was considerable melting of the upper sea ice layer, which could have led to a suitable habitat at the bottom for autotrophic flagellate growth (the higher ratios of N/P). It is suggested that the melting of sea ice in recent years has had obvious influence on the pack ice community in the Arctic Ocean. For example, the biomass of the heterotrophic taxa has increased and heterotrophic bacteria have replaced diatoms as the dominant group.