The study of bacterial community diversity and metabolic function in lake water is of great significance to the healthy development of the urban landscape lake water environment. In this study, Hancheng Lake, Nanhu Lake, Xingqing Lake, and Taohuatan Lake were selected as the study area. Illumina Nova high-throughput sequencing technology was used to study the composition and structure of bacterial communities in four different types of lakes. The correlation between bacterial communities and environmental factors was analyzed using the RDA method. Tax4Fun was used to predict the metabolic function of bacterial communities. The results showed that the diversity of bacterial communities was different in different lakes. The α diversity of Taohuatan Lake was the highest, and that of Xingqing Lake was the lowest. The bacterial community structure of the same lake had a trend of aggregation. The dominant phyla of bacteria in the four lakes were similar, mainly Proteobacteria, Bacteroidetes, and Actinobacteria. The difference was only in the proportion of bacteria. Additionally, the distribution of bacterial communities at the genus level in the four lakes was quite different. The physical and chemical properties of lakes were significantly correlated with bacterial community, and the most critical factor was nitrogen and phosphorus nutrients(P<0.05). Tax4Fun function prediction showed that the metabolic function of bacterial communities in the four lakes was similar, and the relative abundance of amino acid metabolism and carbohydrate metabolism was the highest. In addition, the potential drug-resistant bacterial pollution and the possibility of human infectious diseases were higher. These results are helpful for understanding the current situation of bacteria in urban lakes in Xi'an and providing a theoretical basis for the management and sustainable development of urban lakes.
Keywords: bacterial community; diversity; environmental factors; metabolic function; urban lake.