微塑料（MPs；< 5 mm）已成为全球最突出的环境污染问题之一。微塑料可通过大气迁移扩散至高海拔地区，然后随着降雨或降雪沉积到地表，对自然生态系统的结构和功能造成潜在威胁。陆地和水生生态系统中的微塑料会改变生物体的生长和功能特征。然而，全球气候变暖的背景下，沉积在雪中的微塑料带来的潜在危害却很少引人关注。本文对内蒙古高原地表积雪中采集的微塑料进行了定性和定量分析。结果表明，沉积雪样品中的微塑料相关浓度约为(68 ± 10)~(199 ± 22) MPs∙L^-1，最常见的形态为纤维状，且聚合物组成种类多样，而微塑料的丰度和组成在很大程度上受人类活动的影响。高通量测序结果表明，不同微塑料污染特征的沉积雪样本中细菌和真菌的组成及丰度也不相同，同时微生物功能多样性方面也存在较大差异。微塑料可能对沉积雪中微生物的个体生长和功能表达会产生干扰作用。此外，研究结果还表明，城市中的功能生活区（如垃圾填埋场和郊区）的微塑料污染存在区域差异性。例如，来自发电厂的沉积雪样本中的微塑料丰度最高，而来自郊区的样本中微塑料丰度明显较低。因此，沉积雪中的微塑料会改变微生物的结构和功能，进而可能对生态系统健康构成潜在威胁。

Microplastics (MPs; < 5 mm) have become one of the most prominent global environmental pollution problems. MPs can spread to high altitudes through atmospheric transport and can be deposited by rainfall or snowfall, potentially threatening the structure and function of natural ecosystems. MPs in terrestrial and aquatic ecosystems alter the growth and functional characteristics of organisms. However, little attention has been given to the possible harm associated with MPs deposited in snow, particularly in the context of global climate warming. MPs collected from surface snow in the Inner Mongolia Plateau, China, were used for quantitative analysis and identification. The results showed that MPs were easily detected, and the related concentration was approximately (68 ± 10)-(199 ± 22) MPs·L⁻¹ in snow samples. Fibers were the most common morphology, the polymer composition was largely varied, and the abundance and composition of MPs were linked to human activity to a great extent. High-throughput sequencing results showed that the composition and abundance of microorganisms also differed in snow samples from areas with different MP pollution characteristics, indicating a considerable difference in microbial functional diversity. MPs may have an interference effect on the individual growth and functional expression of microorganisms in snow. In addition, the results showed that functional living areas (e.g., landfills and suburban areas) in cities play an important role in the properties of MPs. For instance, the highest abundance of MPs was found in thermal power plants, whereas the abundance of polymers per sample was significantly lower in the suburban area. The MP contaminants hidden in snow can alter microbial structure and function and are therefore a potential threat to ecosystem health.

• Substantial accumulation of MPs was observed in snow of the Mongolian Plateau, China.

• The pollution characteristics of MPs are influenced by the urban functional areas.

• The plastic residues may change the microbial community structures in snow.

• Alterations in the microbial function may be the result of changes in the microbial populations.