黄河玛曲至临河段硅藻群落组成及水质评价

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.