Response of microbial communities and biogeochemical cycling functions to sediment physicochemical properties and microplastic pollution under damming and water diversion projects

Microbial community succession mediated by planting patterns in the Loess Plateau, China: Implications for ecological restoration

Microbial community succession plays a key role in restoring fragile ecosystems and mitigating ecological degradation. However, the mechanisms by which vegetation restoration promotes ecological restoration and microbial community reconstruction in degraded soils remain unclear. This study utilized metagenomic high-throughput sequencing technology to analyze microbial community dynamics in soil samples collected from eight different planting patterns in the ecologically degraded areas of the Chinese Loess Plateau. The results indicated significant effects of terrain location and restorative cropping patterns on soil microbial abundance and function. In particular, soil C and N nutrient abundance was highest in mixed forest soils, and the total number of microorganisms was highest and more diverse. Therefore, through vegetation restoration, mixed forests significantly enhanced regional ecological functions. Notably, creating mixed forests with both trees and shrubs resulted in optimal ecological functions, providing a valuable direction for vegetation construction and structural optimization in the region.

Microbial Dynamics on Different Microplastics in Coastal Urban Aquatic Ecosystems: The Critical Roles of Extracellular Polymeric Substances

Microplastics (MPs) serve as carriers for microbial community colonization, forming unique ecosystems known as plastispheres in urban aquatic ecosystems. However, interactions among microbes, extracellular polymeric substances (EPS), and MPs remain poorly understood. This study investigates microbial consortia and their EPS secretion behaviors across various plastispheres at two representative coastal urban water sites. Permutational multivariate analysis of variance revealed that MP type significantly influenced microbial community structures in reservoir environments (R2 = 0.60, p < 0.001), highlighting the pronounced impact of MP types in high-quality urban waters. Specific microbial phyla and genera were identified as key contributors to EPS compositional variations across different plastispheres. Hierarchical partitioning results identified Acidobacteria, Nitrospirae, and Planctomycetes as influential phyla positively affecting EPS composition. Spearman correlation analysis pinpointed Robiginitialea (positive correlation) and Fimbriiglobus (negative correlation) as critical genera influencing EPS dynamics. Moreover, EPS-related gene abundance corresponded closely with observed EPS compositional differences. Dominant genes associated with protein biosynthesis included xapD in reservoirs and glnA in bays, while glmS and eno were predominant for polysaccharide biosynthesis in bays. This research advances our understanding of microbial-EPS-MP interactions in urban water systems, offering critical insights into ecological remediation and risk assessment of MP pollution.