为了揭示微塑料类型和剂量对微生物群落的反馈和调节机制,用两种不可降解的微塑料[聚乙烯(PE)和聚氯乙烯(PVC)]和四种可生物降解的微塑料[聚(丁二酸丁二醇酯)(PBS)进行了微观实验,聚羟基链烷酸酯(PHA),聚(己二酸丁二醇酯-共对苯二甲酸酯)(PBAT),和不同水平的聚碳酸亚丙酯(PPC)](1%,7%,和28%)。因此,总碳含量(TC),土壤有机碳(SOC),和微生物生物量碳(MBC)(预计PBS土壤中的MBC)随着微塑料剂量的增加而增加,并以最低的PE剂量率增加。与不可降解的微塑料相比,可生物降解的微塑料创造了更活跃的生态位,同时丰富了更多的病原体。结构方程模型表明,微生物多样性处于类型依赖的集合中,而微生物成分受到微塑料剂量的影响更大,最终。微塑料类型对细菌和真菌多样性的标准化总效应系数分别为-0.429和-0.282,剂量对细菌和真菌成分的标准化总效应系数分别为0.487和0.336。微塑料类型和剂量都显着影响pH值,电导率,总氮,TC,SOC,还有MBC,随后抑制微生物多样性和刺激具有特定途径的微生物组合物。该结果为评估微塑料的潜在风险提供了全面的理解。
To reveal the feedbacks and regulating mechanisms of microplastic types and doses on microbial community, a microcosm experiment was carried out with two non-degradable microplastics [polyethylene (PE) and polyvinyl chloride (PVC)] and four biodegradable microplastics [poly(butylene succinate) (PBS), polyhydroxyalkanoates (PHA), poly(butyleneadipate-co-terephthalate) (PBAT), and polypropylene carbonate (PPC)] at different levels (1 %, 7 %, and 28 %). As a result, the content of total carbon (TC), soil organic carbon (SOC), and microbial biomass carbon (MBC) (expect MBC in PBS soil) increased with increasing doses of microplastics, and increased at the lowest PE dose rate. Biodegradable microplastics created a more active ecological niche while enriching more pathogens than non-degradable microplastics. Structural equation modeling indicated that microbial diversities were in a type-dependent assembly, whereas microbial compositions were more profoundly affected by the microplastic doses, ultimately. The standardized total effect coefficient of microplastic types on bacterial and fungal diversities was - 0.429 and - 0.282, and that of doses on bacterial and fungal compositions was 0.487 and 0.336, respectively. Both microplastic types and doses significantly impacted pH, electrical conductivity, total nitrogen, TC, SOC, and MBC, subsequently inhibiting microbial diversities and stimulating microbial compositions with particular pathways. The results provide a comprehensive understanding for evaluating the potential risk of microplastics.