Tire microplastics rather than polystyrene microplastics reduce soil microbial diversity and network complexity and...

Area of Science:

• Environmental Science
• Soil Science
• Microbiology

Background:

• Microplastic (MP) pollution threatens soil biodiversity, with impacts on microbial communities poorly understood.
• Assessing MP risks requires understanding their effects on soil microbial structure, stability, and assembly processes.

Purpose of the Study:

• To investigate the effects of polystyrene (PS) and tire particle (TP) MPs on soil microbial communities in a maize-planted system.
• To evaluate shifts in microbial diversity, network architecture, and assembly processes under different MP concentrations.

Main Methods:

• Soil samples from a maize system were treated with varying concentrations (0, 1%, 5% w/w) of PS and TP MPs.
• Bacterial and fungal diversity, network complexity, and community assembly processes were analyzed.
• Soil physicochemical properties were correlated with microbial community shifts.

Main Results:

• High-concentration PS MPs (5%) enhanced bacterial diversity and network complexity.
• High-concentration TP MPs (5%) reduced bacterial and fungal diversity, destabilized networks, and homogenized communities.
• TP MPs shifted assembly towards deterministic processes and altered soil stoichiometry (e.g., nutrients, pH, carbon).

Conclusions:

• Polystyrene and tire particle MPs exert divergent impacts on soil microbial communities and functions.
• Tire particle MPs pose significant ecological risks, altering soil chemistry and microbial assembly, necessitating urgent mitigation in agroecosystems.
• Understanding these differential effects is crucial for comprehensive MP risk assessment and management.