State Key Laboratory of Environmental Criteria and Risk Assessment, and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China; School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou 730070, PR China.
State Key Laboratory of Environmental Criteria and Risk Assessment, and State Environmental Protection Key Laboratory of Simulation and Control of Groundwater Pollution, Chinese Research Academy of Environmental Sciences, Beijing 100012, PR China.
Environ Int. 2021 Apr;149:106398. doi: 10.1016/j.envint.2021.106398. Epub 2021 Jan 24.
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）会改变土壤团聚体稳定性。然而，目前的研究还尚未确定这些改变是否会进一步影响不同土壤团聚体中的微生物群落结构和多样性，以及它们是否会影响土壤微生物结构和多样性对不同团聚体分数中 MPs 的响应。在这项研究中，我们结合长期土壤培养实验和土壤分级，研究了聚乙烯微塑料（PE-MPs）对不同粒径土壤团聚体中土壤团聚体性质和微生物群落的影响。结果表明，PE-MPs 的存在显著降低了土壤团聚体的理化性质，抑制了土壤酶的活性，并改变了细菌和真菌群落的丰富度和多样性。这种变化在土壤团聚体水平上产生了显著差异。在粉砂和粘土部分中，细菌的响应敏感性高于大团聚体部分，而真菌在大团聚体部分的响应敏感性高于粉砂和粘土部分。提出了添加 PE-MPs 后土壤团聚体性质和微生物群落之间的关系和路径分析。PE-MPs 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。酸杆菌门、芽单胞菌门、拟杆菌门、担子菌门、毛霉门和球囊霉门的相对丰度与理化性质和土壤酶活性显著相关。酶活性是影响土壤微生物群落结构的直接因素，理化性质（即溶解有机碳、土壤有效磷）可以通过作用于土壤酶活性间接影响这些结构。我们的研究结果有助于从不同土壤团聚体的角度提高对土壤微生物结构和多样性对 MPs 响应的理解。
