The characteristics of phytoplankton community structure and its relationship with environmental factors of a large reservoir in subtropic of Southern China: A case study of Xinfengjiang Reservoir

Abstract

为了解亚热带大型深水贫营养水库的浮游植物群落特征及生态现状，2019年9月至2020年8月对新丰江水库的浮游植物群落结构和水体理化指标进行了周年调查.结果表明，新丰江水库水质达到《地表水环境质量标准》（GB 3838—2002）Ⅰ类标准，综合营养状态指数（TLI（∑））在15~28之间，整体上处于贫营养状态.共检出浮游植物8门89属189种，其中绿藻门94种、蓝藻门36种、硅藻门33种、裸藻门10种和甲藻门9种，分别占总种数的49.74%、19.05%、17.46%、5.29%和4.76%.浮游植物群落结构冬季和春季为绿藻-硅藻型、夏秋季为绿藻-蓝藻型；浮游植物丰度范围为0.33×10⁶~11.78×10⁶ cells/L，均值为3.75×10⁶ cells/L.其时间变化特征为2019年9月至2020年3月呈下降趋势，此后至2020年7月又呈缓慢上升.浮游植物生物量变化范围为0.26~2.49 mg/L，均值为1.19 mg/L，其时间分布与丰度基本一致，其中绿藻门和硅藻门为生物量主要贡献类群；相关分析和典型对应分析（CCA）结果表明，水温是影响新丰江水库浮游植物群落结构的关键因素，其次为透明度和电导率.该研究对于深入认识贫营养水体藻类生态学特征，拓展湖沼学研究范围与思路具有重要意义.;To understand the characteristics of the phytoplankton community structure and its relationship with environmental factors, an investigation was carried out monthly from September 2019 to August 2020 in Xinfengjiang Reservoir, a large oligotrophic reservoir in Southern China. The results showed that the water quality indexes of Xinfengjiang Reservoir met the CriterionⅠaccording to the Surface Water Environmental Quality Standard (GB 3838-2002). A total of 189 phytoplankton species were identified, belonging to 8 phyla and 89 genera. Among these species, 94 were members of Chlorophyta, 36 Cyanophyta, 33 Bacillariophyta, 10 Euglenophyta and 9 Pyrrophyta, accounting for 49.74%, 19.05%, 17.46%, 5.29% and 4.76% of the total phytoplankton species, respectively. The phytoplankton community structure was Chlorella-Diatom form in winter and spring 2020, and Chlorella-Cyanophyta form in summer and autumn 2019. The abundance of phytoplankton ranged from 0.33×10⁶ to 11.78×10⁶ cells/L with an average range of 3.75×10⁶ cells/L. it was higher in autumn and winter in 2019 than that of spring and summer in 2020. The phytoplankton biomass has a range of 0.26-2.49 mg/L with an average of 1.19 mg/L. The temporal trend of biomass was as similar as that of abundance with dominated groups of Cyanophyta and Chlorophyta as well as Chlorophyta and Diatoms Correlation and canonical correspondence analysis showed that water temperature was the key factor affecting phytoplankton community structure in Xinfengjiang Reservoir, followed by water transparency and electrical conductivity. The present study had great significance for further understanding the ecological characteristics of phytoplankton in the oligotrophic reservoir, as well as expanding the study scope of limnology.