Characteristics of bacterial community in the water and surface sediment of the Yellow River, China, the largest turbid river in the world

Purpose: Few studies have described the bacterial community structures of turbid rivers. In this paper, the characteristics of the bacterial community in the water and surface sediment of the Yellow River, China, the largest turbid river in the world, were studied. Materials and methods: Water and sediment samples were collected from six sites along the river. Bacterial community composition was determined using the 16S ribosomal RNA (rRNA) gene clone library technique. The relationship between environmental parameters and bacterial diversity was analyzed. Results and discussion: A total of 1,131 gene sequences were obtained and clustered into 639 operational taxonomic units (at the 97 % identity level), with Proteobacteria as the predominant phylum. The Shannon index for water samples ranged from 3.39 to 4.40 and was generally higher than that in other rivers; this was probably due to the high suspended particulate sediment (SPS) concentration in the Yellow River, which can provide more habitats for both aerobic and anaerobic bacteria. Also, the bacterial diversity of the water samples was slightly higher than that of the surface sediment samples. The bacterial diversity of water increased along the river in the downstream direction, while there was no trend for the sediment. Redundancy analysis indicated that pH, dissolved organic carbon (DOC), and SPS were the main factors controlling the water bacterial community in the Yellow River, and pH, nitrate–nitrogen, and water content were the main factors for the surface sediment bacterial community. Conclusions: This study indicated that the bacterial diversity of the Yellow River is generally higher than that in other rivers, suggesting that SPS plays an important role in regulating bacterial diversity and community structure in aquatic environments.