Ecological Roles and Shared Microbes Differentiate the Plastisphere from Natural Particle-Associated Microbiomes in...

Area of Science:

• Environmental Microbiology
• Ecotoxicology
• Riverine Ecology

Background:

• Microplastics (MPs) are prevalent in urban rivers, forming a "plastisphere" of associated microbes.
• The ecological role of the plastisphere compared to natural particle-associated microbes remains poorly understood.
• Urban rivers exhibit varying levels of microplastic pollution, necessitating comparative studies.

Purpose of the Study:

• To compare microbiomes associated with microplastics (MPs) and natural particles (NPs) in urban rivers.
• To investigate the functional potential and ecological impacts of the plastisphere.
• To assess microbial exchange between MPs and river water (RW).

Main Methods:

• Comparative metagenomic analysis of microbes on MPs, NPs (100-5000 μm), and in RW.
• Sampling across 10 urban river systems with diverse MP pollution levels.
• Analysis of taxonomic and functional gene profiles.

Main Results:

• Plastisphere and NP-associated microbiomes showed taxonomic and functional similarities but distinct specialized taxa.
• The plastisphere exhibited enhanced potential for complex carbohydrate/plastic degradation, nitrate reduction, and antibiotic resistance.
• MPs facilitated the sharing of microbes with RW, possessing enhanced horizontal gene transfer capabilities.

Conclusions:

• The plastisphere plays distinct ecological roles in riverine ecosystems.
• Microplastic pollution uniquely impacts riverine ecosystem function and health.
• Shared microbes may disperse plastisphere-associated traits into the wider river environment.