海珠国家湿地公园浮游植物群落结构时空变化

浮游植物是湿地生态系统的重要组成成分,其数量及群落结构变化会对湿地生态系统的结构和功能产生重要影响。为了解海珠国家湿地公园浮游植物群落结构及时空动态变化特征,于2017年冬、2018年夏两季分别进行了调查。结果表明:海珠国家湿地公园共检到浮游植物171种,隶属7门64属,其中绿藻门、硅藻门和蓝藻门种类分别占总种类的44%、26%和13%;广州平裂藻(Merismopedia cantonensis)和细小平裂藻(Merismopedia minima)在两季均为优势种,冬季啮蚀隐藻(Cryptomonas erosa)也较多;浮游植物群落结构、丰度与生物多样性指数具有明显季节变化,冬季硅藻和绿藻占优,分别占藻类总丰度的32%和29%;夏季蓝藻占绝对优势,占68%;夏季浮游植物平均丰度达(25.58±18.47)×10^6cells·L^-1,约为冬季的3倍;Shannon物种多样性指数和Pielou均匀度指数冬季分别为4.38和0.77,夏季分别为2.92和0.51;从空间上看,海珠湖浮游植物种类、多样性指数均较低,而丰度较高;塘涌和西江涌硅藻丰度最大,其他位点均以蓝藻占优;水体总氮和温度是影响浮游植物群落结构变化的重要因素。本研究可为海珠国家湿地公园的管理和保护提供参考。

Spatial and temporal dynamics of phytoplankton community structure in Haizhu National Wetland Park.

Phytoplankton is an important component of wetland ecosystems.Changes in the quantity and community structure of phytoplankton may affect the structure and function of wetlands.The spatial and temporal dynamics of phytoplankton in Haizhu National Wetland Park in winter(2017)and summer(2018)were investigated.Results showed that 171 species belonging to 64 genera in seven phyla were recorded.Chlorophyta,Bacillariophyta and Cyanophyta accounted for 44%,26%and 13%of all the species,respectively.The dominant species were Merismopedia cantonensis and Merismopedia minima in both seasons,with Cryptomonas erosa being also among the dominant species in winter.The community structure,cell density and biodiversity index of phytoplankton varied significantly between seasons.In winter,the community was dominated by bacillariophyta and chlorophyta,accounting for 32%and 29%of the phytoplankton;whereas in summer,the community was dominated by cyanophyta,with a 68%contribution.The abundance of phytoplankton in summer was(25.58±18.47)×10^6 cells·L^-1,about three times high as that in winter.The Shannon index and Pielou index showed similar trends,being high in winter(4.38 and 0.77)and low in summer(2.92 and 0.51).Spatially,species richness and diversity index were low,but abundance was high in Haizhu Lake.The abundance of bacillariophyta was the highest in the wetland of Tang River and Xijiang River,while other sites were dominated by cyanobacteria.Total nitrogen and temperature were important factors affecting the phytoplankton community structure.Our results are useful for management and protection of Haizhu National Wetland Park.