三亚湾近岸浮游纤毛虫群落的昼夜变化特征

Diel variation of community structure of planktonic ciliates in coastal ecosystem of Sanya Bay

浮游纤毛虫广泛分布于海洋环境中,是连接微食物环和经典食物链的关键环节,在生态系统的物质传递和能量流通中占据重要地位。为深入认识纤毛虫在热带海区的分布特征及其生态功能,于2014年4月在三亚湾近岸海区设置昼夜连续监测站点,分早晨(6:00)、中午(12:00)、傍晚(18:00)和夜晚(24:00)四个时间点分别采集浮游纤毛虫及环境因子检测样品,并用分子生物学方法分析了表层水体浮游纤毛虫群落结构的昼夜变化特征。结果显示:1)表层浮游纤毛虫多样性高,共获得79条不同代表序列;2)不同时间表层海水中浮游纤毛虫多样性差异显著,表现为白天降低,夜晚升高,其多样性高低依次为:早晨[48个操作分类单元(operational taxonomic unit,OTU)]>夜晚(37个OTU)>傍晚(32个OTU)>中午(29个OTU)。浮游纤毛虫群落结构表现出昼夜变化现象,可能是因为不同类群纤毛虫具有不同的空间分布规律。

Planktonic ciliates are widespread micro-zooplankton in marine ecosystem and are considered as a key link between microbial loop and classic food chain as they play important roles in transfer processes of material and energy in the ecosystem.To better understand the distribution and ecological function of planktonic ciliates in tropical ecosystem,ciliate samples were collected in the coastal waters of Sanya Bay at6:00,12:00,18:00and24:00,respectively,in April2014.Species diversity and community structure of ciliate from different times were analyzed by molecular detection based on species-specific primers.The results were as follows.1)Planktonic ciliate showed high diversity,with about79operational taxonomic units(OTUs)detected.2)Significant variation of species diversity was uncovered at different times during a day,showing a decrease trend in day time but increase trend at night time and the order was morning[48OUTs(operational taxonomic units)]>night(37OTUs)>evening(32OTUs)>midday(29OTUs).The reason may be that different ciliate populations have different distribution modes.