Abstract: Bacterial diversity in water and sediments of Daihai Lake was analyzed by culture method and metagenomic sequencing in this study. The bacteria isolated by culture method belonged to 4 phyla, 6 classes, 18 orders, 25 families, 47 genera, 77 species, including 20 potential novel species, the dominant phyla were Proteobacteria and Firmicutes. It was found that 0.22 μm filtration can remove most common bacteria and improve the detection of novel species. A total of 83 phyla were identified by metagenomic sequencing. Proteobacteria and Bacteroidetes were the dominant phyla. Metagenomic sequencing identified one unclassified phyla and 50 candidate phyla, of which 33 were candidate phyla radiation (CPR). The results showed that there are high abundance and diversity of bacteria, and abundant CPR strains in Daihai Lake. The results laid a foundation for further research on microbial resources mining and ecological functions in Daihai Lake.

Key words: Daihai Lake, bacterial diversity, metagenomic sequencing, culture, CPR