汉江中下游后生浮游动物群落结构及其与环境因子的关系

Metazooplankton community structure and its relationship with environmental factors in the middle and lower reaches of Hanjiang River

在汉江中下游江段干流丹江口等7个点位开展了4次后生浮游动物群落结构和水环境特征调查,使用主成分分析、Spearman相关分析和冗余分析等统计分析方法研究了后生浮游动物群落和环境因子的关系。结果表明:汉江中下游干流江段共检出后生浮游动物51种,包括枝角类16种,桡足类16种,轮虫19种。其中汉江干流汉川段丰度最高为1500.1 ind.·L^(-1),丹江口丰度最低为31.3 ind.·L^(-1);汉江干流生物量汉川段最高为1.80 mg·L^(-1)(2018年7月),丹江口的生物量最低为0.05 mg·L^(-1)(2017年11月)。汉江中下游后生浮游动物丰度、生物量总的趋势是沿水流方向均呈升高趋势。与过去监测资料相比后生浮游动物丰度、生物量呈急剧增加和种类下降趋势。PCA分析结果显示,氮、磷等环境因子对2018年1月站点的影响明显,而温度与7月份站位成正相关关系;通过冗余分析显示环境因子对后生浮游动物群落的影响规律性不明显,考虑后生浮游动物群落变化不仅仅受沿江水质污染影响,还可能受其他未调查因子的影响。

Four investigations on the community structure and water environment characteristics of metazooplankton were carried out at seven points such as Danjiangkou,the main stream of the middle and lower reaches of the Hanjiang River.The relationship between metazooplankton community and environmental factors was studied by using statistical analysis methods such as principal component analysis,Spearman correlation analysis and redundancy analysis.The results showed that 51 species of metazooplankton were detected in the middle and lower reaches of the Hanjiang River,including 16 species of cladocerans,16 species of copepods and 19 species of rotifers.The highest abundance in Hanchuan section of the main stream of Hanjiang River was 1500.1 ind.·L^(-1),and the lowest abundance in Danjiangkou was 31.3 ind.·L^(-1);The highest biomass in Hanchuan section of Hanjiang River was 1.80 mg·L^(-1)(July 2018),and the lowest biomass in Danjiangkou was 0.05 mg·L^(-1)(November 2017).The abundance and biomass of metazooplankton in the middle and lower reaches of Hanjiang River increased along the flow direction.Compared with the previous monitoring data,the abundance and biomass of metazooplankton increased sharply and the species decreased.The results of PCA analysis showed that environmental factors such as nitrogen and phosphorus had an obvious impact on the station in January 2018,and the temperature had a positive correlation with the station in July;Redundancy analysis showed that the impact of environmental factors on metazooplankton community was not obvious.Considering that the change of metazooplankton community was not only affected by water pollution along the river,but also affected by other factors not investigated.