Geographic Variation in Microbes and Water Quality in Urban Lakes Restored with Submerged Plants: Migration of Microbial Communities Across Habitats

Abstract As an important component of urban ecology, the water quality in urban lakes directly affects the stability of the entire ecosystem. However, with the acceleration of urbanization, the eutrophication of urban lakes has become increasingly serious, exacerbated by the disappearance and destruction of submerged plants. Therefore, protecting and restoring submerged plants and improving lake water quality using bioremediation have become focal points of contemporary research. This study of a treated urban lake that relies on the reconstruction of submerged plants as the objective, revealed a strong correlation between the physicochemical properties of lake water and microbial communities. The bacterial community fluctuated in species richness among different sites, but the composition of the bacterial community in different water layers at the same site was consistent. The bacterial community movement between water, submerged plants, and sludge, with species migration between water and submerged plants exceeding 70% of all movements. Microorganisms such as Methylobacterium (Methylobacterium spp.), Cloacibacterium, and Sphingomonas colonized the surface of submerged plants, enhancing the transformation of nitrogenous compounds and reducing COD levels in the lake. These findings provide a significant foundation for a deeper understanding of the microbial ecological characteristics of lake ecosystems and their purification mechanisms. Overall, this study not only provides the scientific basis and technical support for the management and restoration of eutrophic lakes but also helps to understand better and protect urban lake ecosystems and promote the sustainable development of lake ecosystems.