灞河城市段浮游生物群落结构时空变化及其与环境因子的关系

为了解灞河城市段浮游生物群落结构及其与环境因子之间的关系,于2016年9月至2017年7月每2个月进行一次采样分析。调查期间共鉴定出浮游植物7门63属,其中绿藻门种类数最多(34.9%),其次为硅藻门(30.2%);浮游动物4类45种,以轮虫(48.9%)和原生动物(24.4%)为主。浮游植物和浮游动物的丰度分别为0.73×10~4—98.5×10~4个/L和20—1084个/L,在时空分布上均呈现下游高于上游的趋势,峰值均出现在夏季。根据水体透明度、溶解氧、总磷、总氮、高锰酸盐指数和重金属等理化指标、浮游生物丰度、Shannon-Wiener多样性指数和Margalef丰富度指数对灞河城市段水质状况进行综合评价,结果显示,所研究流域总体为中污状态,上游景观河道内的水生植物对水体具有一定的修复能力。典范对应分析表明,水温、总氮、pH、溶解氧和汞是浮游植物群落分布的主要影响因子;影响浮游动物群落分布的主要因子为水温、总氮、总磷、叶绿素a和汞。

Spatial and temporal variation of the plankton community and its relationship with environmental factors in the city section of the Ba River

To evaluate the relationship between plankton community composition and environmental factors in a city section of the Ba River, the samples were collected and analyzed every two months from September 2016 to July 2017. In the study, 7 phyla and 63 genera of phytoplankton were identified, with the most abundant species of Chlorophyta (34.9%), followed by Bacillariophyta (30.2%). A total of 45 zooplankton species from 4 classes were identified, dominated by Rotifera (48.9%) and Protozoa (24.4%). The abundances of phytoplankton and zooplankton were 0.73×10⁴ to 98.5×10⁴ ind/L and 20 to 1084 ind/L, respectively. The spatial and temporal distribution of abundances of both phytoplankton and zooplankton showed a decreasing trends from the downstream to the upstream, with the peaks in summer. The water quality was comprehensively evaluated using plankton abundance, Shannon diversity index, Margalef abundance index, and physicochemical indexes including transparency, dissolved oxygen, total phosphorus, total nitrogen, permanganate index, and heavy metal content. The results showed that the city section of the Ba River was moderately polluted and that the aquatic plants in the river bed of the upstream landscape river have the ability to remove the pollutants. Canonical correspondence analysis indicated that water temperature, total nitrogen, pH, dissolved oxygen,and mercury are the key factors in phytoplankton community distribution, and that water temperature, total nitrogen, total phosphorus, chlorophyll-a, and mercury are the key factors in zooplankton community distribution.