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

C values of PE- and PVC-treated aggregates ranged from -25.34 to -20.85‰, while those of PLA and PHA ranged from -16.29 to -9.26‰. Notably, MPs altered the direction of carbon flow between aggregates, reduced carbon flux, and accelerated carbon emissions. RFP and PLS-PM analyses revealed that persistent MPs affected carbon flow primarily via abiotic factors, whereas biodegradable MPs influenced it via biotic factors. These findings provide insights into the mechanisms by which MPs impact aggregate-associated carbon, highlighting their effects on soil ecosystem services.