九寨沟国家级自然保护区长海夏季浮游植物群落结构及生态评价

高山湖泊对于全球气候变化及人类影响是一个极为敏感的参照系统.九寨沟国家级自然保护区长海作为一个独特的高山湖泊,研究其浮游植物群落结构及其与环境的关系,评估其水质现状及影响因素,有着重要的意义.本文于2014年7月对长海浮游植物群落结构进行了研究.全湖共布设12个采样点,并在中心采样点进行了垂直分层采样.本次调查共发现浮游植物6门38属63种,平均丰度为6.98×10⁵cells/L,平均生物量为0.31 mg/L.浮游植物的水平分布差异不大;在垂直分布上,浮游植物的丰度从表层0.5 m至水下50 m呈现先增加后减少的趋势,在20 m水深处达到最大.长海浮游植物的优势种是长海小环藻(Cyclotella changhai)和飞燕角甲藻(Ceratium hirundinella),长海小环藻数量较多,飞燕角甲藻生物量较大.长海浮游植物多样性指数较低,综合各类水质评价方法,可以得出九寨沟长海处于贫-中营养状态.

Phytoplankton community structure and ecological evaluation in summer, Lake Changhai of Jiuzhaigou National Nature Reserve

Alpine lakes are sensitive reference systems of global climatic change and other human impacts. As a unique alpine lake, Lake Changhai of Jiuzhaigou National Nature Reserve has important significance in studying its phytoplankton community structure and it''s relationship with the environment. It is also important to assess the status of water quality and its influencing factors. In order to understand the phytoplankton community structure, 12 sites were selected to collect phytoplankton samples in July 2014. Vertical stratified sampling was performed at the central sampling point. The 63 taxa of phytoplankton belonging to 38 genera in 6 phyla were identified, the average phytoplankton abundance was 6.98×10⁵ cells/L, the average phytoplankton biomass was 0.31 mg/L. There is no significant difference in the horizontal distribution of the phytoplankton. In the vertical distribution, the abundance of phytoplankton increased first and then decreased from 0.5 m to 50 m, and reached the maximum at the depth of 20 m. Cyclotella changhai and Ceratium hirundinella were the dominant species. Cyclotella changhai were higher amounts, Ceratium hirundinella were higher biomass. The phytoplankton diversity index was low. Synthesizing all kinds of methods to evaluate water quality, Lake Changhai was in a poor-medium pollution state.