Microplastics (MPs) alter soil aggregation stability. However, studies have yet to determine whether these alterations further affect microbial community structures and diversities within different soil aggregates and whether they influence the responses of soil microbial structures and diversities to MPs in different aggregate fractions. In this study, long-term soil incubation experiments and soil fractionation were combined to investigate the effects of polyethylene microplastics (PE-MPs) on soil aggregate properties and microbial communities in soil aggregates with different particle sizes. Results showed that the existence of PE-MPs significantly reduced the physicochemical properties of soil aggregates, inhibited the activities of soil enzymes, and changed the richness and diversity of bacterial and fungal communities. Such variations exerted notable differences in soil aggregate levels. The response sensitivity of bacteria in the silt and clay fraction was higher than that in the macroaggregate fraction, but the response sensitivity of fungi in the macroaggregate fraction was higher than that in the silt and clay fraction. Relationships and path analysis between soil aggregate properties and microbial communities after PE-MPs addition were proposed. PE-MPs affected microbial community structures by directly and indirectly influencing soil microenvironmental conditions. The relative abundances of Acidobacteria, Gemmatimonadetes, Bacteroides, Basidiomycota, Chtridiomyota, and Glomeromycota were significantly correlated with physicochemical properties and soil enzyme activities. Enzyme activities were direct factors influencing soil microbial community structures, and physicochemical properties (i.e., dissolved organic carbon, soil available phosphorus) could indirectly affect these structures by acting on soil enzyme activities. Our findings helped improve our understanding of the responses of soil microbial structures and diversities to MPs through the perspective of different soil aggregates.

微塑料（MPs）会改变土壤的团聚稳定性。然而，尚未确定这些改变是否进一步影响不同土壤聚集体中微生物群落结构和多样性，以及它们是否影响土壤微生物结构和多样性对不同聚集体组分中MPs的响应。在这项研究中，结合长期的土壤培养实验和土壤分馏，以研究聚乙烯微塑料（PE-MPs）对不同粒径的土壤团聚体中土壤团聚体特性和微生物群落的影响。结果表明，PE-MPs的存在显着降低了土壤团聚体的理化特性，抑制了土壤酶的活性，改变了细菌和真菌群落的丰富性和多样性。这种变化在土壤团聚体水平上产生了显着差异。淤泥和黏土中细菌的响应敏感性高于大骨料中的细菌，但真菌对巨骨料中细菌的响应敏感性高于淤泥和黏土中的细菌。提出了添加PE-MPs后土壤团聚体性质与微生物群落的关系和通径分析。PE-MP通过直接和间接影响土壤微环境条件来影响微生物群落结构。的相对丰度 但真菌在大骨料级分中的响应敏感性高于粉砂和黏土级分。提出了添加PE-MPs后土壤团聚体性质与微生物群落的关系和通径分析。PE-MP通过直接和间接影响土壤微环境条件来影响微生物群落结构。的相对丰度 但真菌在大骨料级分中的响应敏感性高于粉砂和黏土级分。提出了添加PE-MPs后土壤团聚体性质与微生物群落的关系和通径分析。PE-MP通过直接和间接影响土壤微环境条件来影响微生物群落结构。的相对丰度酸杆菌门，芽单胞菌门，拟杆菌属，担子菌门，Chtridiomyota，和球囊菌门与理化性质和土壤的酶活性显著相关。酶的活性是影响土壤微生物群落结构的直接因素，理化特性（即溶解的有机碳，土壤有效磷）可以通过影响土壤酶的活性而间接影响这些结构。我们的发现有助于从不同土壤团聚体的角度增进对土壤微生物结构和多样性对MP响应的理解。