LDPE microplastic films alter microbial community composition and enzymatic activities in soil

Area of Science:

• Environmental Science
• Soil Science
• Microbiology

Background:

• Microplastic contamination is a growing concern, extending from aquatic to terrestrial ecosystems.
• The impact of microplastics on soil ecosystems, particularly enzymatic activities and microbial communities, remains under-investigated.

Purpose of the Study:

• To investigate the effects of polyethylene (PE) microplastics on soil enzymatic activities.
• To analyze the impact of PE microplastics on soil bacterial community structure and diversity.
• To characterize the microbiota colonizing PE microplastics in soil.

Main Methods:

• Soil amendment with PE microplastics (2000 fragments/kg).
• Measurement of soil enzymatic activities (urease, catalase, invertase).
• High-throughput sequencing of 16S rRNA for bacterial community analysis.
• Analysis of microbial diversity and taxonomic composition on microplastics and in soil.

Main Results:

• Significant increase in urease and catalase activities after 15 days; no change in invertase.
• No significant alteration in soil bacterial alpha diversity, but lower diversity on microplastics.
• Distinct bacterial community composition in amended soil and on PE microplastics after 90 days.
• Higher abundance of plastic-degrading bacteria and pathogens on microplastics.
• Enriched amino acid metabolism and xenobiotics biodegradation pathways on microplastics.

Conclusions:

• PE microplastics can alter soil enzymatic activities and bacterial community structure.
• Microplastics serve as a distinct microbial habitat in soil, differing from aquatic environments.
• These alterations suggest potential impacts on soil ecological functions.