Spatiotemporal Distribution and Its Influence Factors of Diatoms in the Middle and Lower Reaches of Hanjiang River

LIU Qingxiang1,2, WANG Ting1,2, XU Xuming1,2, NI Jinren1,2,†

1. School of Environment and Energy, Peking University Shenzhen Graduate School, Shenzhen 518055; 2. Key Laboratory of Water and Sediment Sciences (MOE), Department of Environmental Engineering, Peking University, Beijing 100871; † Corresponding author, E-mail: nijinren@iee.pku.edu.cn

Abstract To study the temporal and spatial distribution and its influence factors of diatoms in the middle and lower reaches of Hanjiang River, diatom in water and sediment were sampled from 5 monitoring sites in Spring and Fall, 2014. Based on 18S RRNA Illumina Miseq high-throughput sequencing technology, 160 species belonging to 111 genuses, 49 families, 28 orders and 3 classes were identified, of which sediment diatom genuses accounted for 98.6%. The species abundance was higher than that of the previous studies, suggesting the significant advantage of high-throughput sequencing technology in diatom identification. The community composition and dominant species in water and sediment were remarkably different, i.e., Pinnularia, Cyclotella and Nitzschia were the dominant species in water, while the dominant species in sediment were Pinnularia, Nitzschia and Navicula. Meanwhile, there exists obvious difference in temporal and spatial distribution of diatom community, due to the fact that Shannon diversity index displayed apparent spatial heterogeneity and diatom species in sediment were higher than that in water; from the view of season changes, the Shannon diversity index in fall were higher than that in spring. Furthermore, total nitorgen, ammonia nitrogen, nitrate and total phosphorus displayed great impact on diatom community composition. As results, controlling nitrogen and phosphorus concentration in the middle and lower reaches of Hanjiang River will be of great importance to avoid diatom blooms. Key words high-throughput sequencing; Hanjiang River; diatom; temporal and spatial distribution; environmental factor