Chemical Characteristics of Atmospheric Precipitation and Their Effects on Microbial Diversity in Baotou, China

Lili Wang¹Yupin Yang¹Li Gao^1*Zhichun Gao^2*

• ¹College of Ecology and Environment, Baotou Teacher’s College, Baotou, China
• ²Baotou Branch, Inner Mongolia Environmental Monitoring Center, Baotou, China

To address the critical knowledge gap in understanding the coupling of atmospheric precipitation chemistry and microbial communities in arid/semi-arid industrial cities—where existing studies have long focused on humid regions but overlooked the unique "sand-dust-agriculture-industry" compound pollution—this study systematically explored the interactive mechanisms, assembly processes, and ecological/health implications of precipitation microbes in Baotou, a typical heavy-industry hub in northern China. By integrating high-throughput sequencing, chemical analysis, and environmental modeling, three core innovations were identified: (1) Baotou’s precipitation, characterized by neutral pH but abnormally high ion loading (dominated by Ca²⁺, NH₄⁺, SO₄²⁻), forms a unique chemical microenvironment shaped by combined sand-dust input, agricultural fertilization, and coal combustion—distinct from the pollution-driven patterns in humid regions. (2) Microbial community assembly is predominantly governed by stochastic processes (drift and dispersal limitation accounting for >79% in bacteria and >86% in fungi), with fungi exhibiting significantly broader niche width and overlap than bacteria (p<0.05). This contrasts sharply with humid regions where deterministic selection (e.g., nutrient availability) typically dominates, highlighting adaptive strategies of microbes under compound stress. (3) Functional differentiation reveals novel ecological and health insights: bacteria primarily drive carbon/nitrogen cycling (supporting potential atmospheric pollutant biodegradation), while fungi show balanced saprotrophic (48.03%) and pathogenic (48.24%) traits—with fungal pathogens (e.g., Cladosporium, Alternaria) exhibiting higher abundance than bacterial pathogens, forming a "fungal-dominated" health risk pattern unique to arid industrial atmospheres. This study provides a pioneering framework for deciphering precipitation chemistry-microbe interactions in complex polluted arid regions, offering actionable guidance for atmospheric pollution control and public health risk assessment in similar industrial cities globally.