Abstract：
Although pervasive microplastics (MPs) pollution in terrestrial ecosystems invites increasing global concern, impact of MPs on soil microbial community assembly and ecosystem multifunctionality received relatively little attention. Here, we manipulated a mesocosm experiment to investigate how polyethylene MPs (PE MPs; 0, 1%, and 5%, w/w) influence ecosystem functions including plant production, soil quality, microbial community diversity and assembly, enzyme activities in carbon (C), nitrogen (N) and phosphorus (P) cycling, and multifunctionality in the maize-soil continuum. Results showed that PE MPs exerted negligible effect on plant biomass (dry weight). The treatment of 5% PE MPs caused declines in the availability of soil water, C and P, whereas enhanced soil pH and C storage. The activity of C-cycling enzymes (α/β-1, 4-glucosidase and β-D-cellobiohydrolase) was promoted by 1% PE MPs, while that of β-1, 4-glucosidase was inhibited by 5% PE MPs. The 5% PE MPs reduced the activity of N-cycling enzymes (protease and urease), whereas increased that of the P-cycling enzyme (alkaline phosphatase). The 5% PE MPs shifted soil microbial community composition, and increased the number of specialist species, microbial community stability and networks resistance. Moreover, PE MPs altered microbial community assembly, with 5% treatment decreasing dispersal limitation proportion (from 13.66% to 9.96%). Overall, ecosystem multifunctionality was improved by 1% concentration, while reduced by 5% concentration of PE MPs. The activity of α/β-1, 4-glucosidase, urease and protease, and ammonium-N content were the most important predictors of ecosystem multifunctionality. These results underscore that PE MPs can alter soil microbial community assembly and ecosystem multifunctionality, and thus development and implementation of practicable solutions to control soil MPs pollution become increasingly imperative in sustainable agricultural production.
摘要：
尽管陆地生态系统中普遍存在的微塑料（MPs）污染引起了全球越来越多的关注，MPs对土壤微生物群落组装和生态系统多功能性的影响受到的关注相对较少。这里,我们操纵了一个中观实验，以研究聚乙烯MPs(PEMPs；0，1%，5%,w/w)影响生态系统功能，包括植物生产，土壤质量,微生物群落多样性和组装，碳（C）中的酶活性，氮（N）和磷（P）循环，玉米-土壤连续体中的多功能性。结果表明，PEMPs对植物生物量（干重）的影响可忽略不计。5%PEMPs处理导致土壤水分有效性下降，C和P,而土壤pH值和碳储量增强。1％PEMPs可促进C循环酶（α/β-1，4-葡萄糖苷酶和β-D-纤维二糖水解酶）的活性，而β-1，4-葡萄糖苷酶被5%的PEMPs抑制。5％的PEMPs降低了N循环酶（蛋白酶和脲酶）的活性，而P循环酶（碱性磷酸酶）的增加。5%PEMPs改变了土壤微生物群落组成，增加了专业物种的数量，微生物群落稳定性和网络抗性。此外，PEMP改变了微生物群落组装，5%处理降低了扩散限制比例(从13.66%降至9.96%)。总的来说,生态系统多功能性提高了1%的浓度，同时降低5%浓度的PEMPs。α/β-1,4-葡萄糖苷酶的活性,脲酶和蛋白酶，氨氮含量是生态系统多功能性的最重要预测因素。这些结果强调了PEMPs可以改变土壤微生物群落组装和生态系统多功能性，因此，在可持续农业生产中，开发和实施控制土壤MP污染的可行解决方案变得越来越重要。
