亚热带和热带环境下夜光藻的摄食压力

Grazing pressure of Noctiluca in subtropical and tropical seas

2015年以广西三娘湾海域为亚热带海区,三亚海域为热带海区,利用稀释法开展了现场培养实验,测定热带和亚热带海区夜光藻对浮游植物、微型浮游动物对浮游植物的摄食压力,研究了夜光藻对不同粒径的浮游生物的摄食作用.结果表明:两个海区都有比较高的生长率和摄食率,其中细菌有最高的生长率和摄食死亡率;夜光藻的摄食率,从总浮游植物、微微型浮游植物到聚球藻、细菌逐渐增高.亚热带海区与热带海区相比,微型浮游动物的摄食压力更小,表明低温影响了浮游动物的摄食活性;而营养盐是引起亚热带海区高生长率的主要因素.

The growth and mortality rates of phytoplankton due to microzooplankton grazing and Noctiluca grazing were estimated at Guangxi( subtropical area) and Sanya( tropical area) in 2015. Results showed that the phytoplankton growth rates and mortality rates were high in both seas. The highest growth rates and mortality rates occurred along with bacteria. The ingestion rate of Noctiluca decreased gradually from bacteria,Synechococcus,picoeukaryotes and total phytoplankton. The grazing pressure of the microzooplankton on phytoplankton in the subtropical area is smaller than in the tropical area,indicating that the low temperature affects the feeding activity of the zooplankton. The nutrients are the major factor that causes the high growth rate.