Microplastic-Induced Alterations in Soil Aggregate-Associated Carbon Stabilization Pathways: Evidence from δ¹³C...

Area of Science:

• Soil Science
• Environmental Chemistry
• Ecology

Background:

• Microplastics (MPs) are pervasive environmental contaminants impacting soil ecosystems.
• The specific mechanisms by which MPs affect soil organic carbon (SOC) stability within soil aggregates are not fully understood.

Purpose of the Study:

• To investigate the impact of persistent (polyethylene, PVC) and biodegradable (PLA, PHA) microplastics on soil aggregate stability and carbon dynamics.
• To elucidate the mechanisms by which different types of MPs influence soil organic carbon flow and microbial activity.

Main Methods:

• A one-year field experiment was conducted in an arid agricultural region.
• Stable isotope techniques (δ13C) were employed to trace soil organic carbon flow.
• RFP and PLS-PM analyses were used to differentiate the influence of MPs on abiotic and biotic factors.

Main Results:

• Persistent MPs (PE, PVC) reduced soil aggregate stability, while biodegradable MPs (PLA, PHA) maintained it.
• PE and PVC treatments altered organic carbon distribution within aggregates, whereas PLA and PHA enhanced it.
• MPs modified carbon flow direction, reduced carbon flux, and increased carbon emissions; persistent MPs acted via abiotic factors, and biodegradable MPs via biotic factors.

Conclusions:

• Microplastic type significantly influences soil aggregate stability and carbon cycling.
• Biodegradable MPs show potential for mitigating the negative impacts of persistent MPs on soil carbon.
• Understanding MP-soil interactions is crucial for assessing and managing soil ecosystem services.