Microplastics distribution and impacts on soil microbial communities in alpine area.

Area of Science:

• Environmental Science
• Microbiology
• Ecotoxicology

Background:

• Microplastic (MP) contamination is a growing global concern, with significant impacts on terrestrial ecosystems.
• Understanding MP effects on soil microbial communities is crucial, especially in sensitive alpine environments.
• Limited data exists on MP distribution and ecological consequences in high-altitude regions like Lhasa.

Purpose of the Study:

• To investigate the distribution characteristics of microplastics in alpine soils.
• To analyze the impact of microplastics on soil microbial community structure and composition.
• To identify key environmental and soil factors influencing microplastic presence and microbial diversity.

Main Methods:

• Field sampling of 63 soil samples across 7 counties in the Lhasa area.
• Microplastic isolation using density separation and identification via Fourier-transform infrared spectroscopy (FTIR).
• Microbial community analysis using high-throughput sequencing for bacteria and fungi.

Main Results:

• Microplastic abundance averaged 244.65 items/kg, with films and fragments <500 μm being dominant.
• Polyethylene (PE) and Polypropylene (PP) were the most common polymer types, often black or green.
• Microplastic abundance significantly altered soil microbial communities, decreasing sensitive taxa (e.g., Kribbella) and increasing tolerant ones (e.g., Sulfurifustis), particularly affecting fungi.

Conclusions:

• Alpine soils in the Lhasa region are contaminated with microplastics, primarily small films and fragments.
• Microplastic abundance directly influences soil microbial community structure, favoring tolerant species.
• Environmental factors (temperature, radiation) and soil properties (SOC, TN) drive spatial variations in microbial communities and microplastic distribution.