To further investigate the water quality in the Maqu-Linhe section of the Yellow River, which is an important water source, diatoms were collected from ten sites in spring and autumn of 2015. Based on the morphological identification method, 24 species belonging to 2 classes, 9 orders, 12 families, and 13 genera were characterized. The cell density and biomass of diatom were lower in spring than those in autumn, which was further proved by NMDS and ANOSIM analysis. Water quality assessment based on indicator diatoms revealed that Nitzschia palea indicating polysaprobic zone was detected in some sites such as Linhe, Qingtongxia, Lanzhou, and Maqu, which was consistent with the assessment from the Shannon diversity index (H). Water quality was characterized as slight-moderate pollution with low diatom diversity in the Maqu-Linhe section of the Yellow River. The water quality of this river section in spring (H=1.91±0.67) was slightly better than that in autumn (H=1.58±0.49), which might be related to the higher DNR in spring.

为深入了解黄河玛曲至临河段这一重要水源地的水质, 于2015年春季和秋季分别在10个采样断面采集硅藻群落样品。利用形态学鉴定方法, 共鉴定出硅藻2纲9目12科13属24种。NMDS和ANOSIM分析结果显示, 硅藻群落组成具有显著的季节差异, 春季硅藻的细胞密度和生物量均低于秋季。基于硅藻指示生物法和香农多样性指数(H)法进行水质评价, 发现指示多污带的Nitzschia palea在临河、青铜峡、兰州和玛曲等站点均有检出, 黄河玛曲至临河段的硅藻多样性较低, 整体水质为轻–中度污染。此外, 该河段春季的水质(H=1.91±0.67)稍好于秋季(H=1.58±0.49), 可能与春季更高的光照强度有关。