Role of microplastics in microbial community structure and functions in urban soils

Evidence from the laboratory suggests that microplastics (MPs) can harm soil microorganisms, affecting the structures and functions of microbial communities. The impact of soil MPs on microbes in actual urban environments with high human activity levels, however, has not been well reported. To investigate the MP effect on urban soil microorganisms under complex scenarios, we analyzed 42 soil samples from standardized plots of 7 urban functional zones. We report that urban green spaces are important for studying microbial diversity in the study area, and they also contribute to the global homogenization of soil microbes and genes. Bacterial communities in soils enriched with various MPs showed greater differences in OTUs than fungi. Compared to low-MP soils, most ARGs and nutrient cycling genes had similar or slightly lower abundances in soils with high levels of MPs. The coupling of pollutant factors with MPs as independent variables had significant explanatory power for both positive and negative correlations in PLS-PM analysis. Specifically, PET and PP MPs explained 3.54% and 6.03%, respectively, of the microbial community and functional genes. This study fills knowledge gaps on the effects of MPs on urban soil microbial communities in real environments, facilitating better management of urban green spaces.