Microbial community analysis and correlation with 2-methylisoborneol occurrence in landscape lakes of Beijing

The microbial community is an important factor influencing the health of the water ecosystem in landscape lakes; in particular, proliferation of some cyanobacteria could cause odor problems. Exploring the microbial community is important for water quality management. In this study, focusing on seven landscape lakes in Beijing, the microbial communities were investigated based on 16S rRNA gene amplicon sequencing, and typical odor-causing compounds and interfering factors were identified. The results showed that 2-methylisoborneol (MIB) was the major odor-causing compound responsible for the earthy/musty odor in landscape lakes. For algal communities, Chlorella and Diatoms were the main eukaryote algae in the water. The bacterial community was dominated by Proteobacteria at the phylum level, and then Cyanobacteria, Actinobacteria, and Firmicutes, etc., most of which were the major phyla of the heterotrophic bacterial population. The richness and diversity of bacteria in natural-water-source lakes were higher than those in reclaimed-water-source lakes. Synechococcus (Cyanobacteria) and GKS98 (Proteobacteria) in reclaimed-water-source lakes were higher than those in natural-water-source lakes, however, CL500-29 (Actinobacteria) in natural-water-source lakes was higher than that in reclaimed-water-source lakes. These bacteria also had significantly positive correlations with MIB. Cyanobacteria and Actinobacteria were the main MIB compound contributors to the variability of MIB in the landscape lakes in Beijing.