meta

Escalating microplastics (MPs) pollution poses an emerging threat to soil carbon storage. However, the feedback loops between MPs, microbial communities, and climate change remain poorly resolved. In this study, we conducted a global meta-analysis of 508 observations from 51 publications, systematically quantifying the response of soil organic carbon (SOC) fractions and microbial traits to MPs under diverse climate stressors (e.g., drought, warming). The resultsreveal a critical carbon trade-off: while MPs served as exogenous carbon source, expanding SOC pools by 50.4%, they simultaneously destabilized these pools by accelerating respiratory losses (CO2+49.5%). This "accumulation-mineralization"paradox was most pronounced with biodegradable MPs, which acted as labile carbon source triggering intense microbial priming effects, particularly under high-dose and short-term exposure scenarios. Microbiologically, MPs exerted strong environmental filtering pressures, reducing α diversity and the fungal/bacterial ratio (F/B -10.3%), while significantly increasing community heterogeneity (β diversity+21.6%). Crucially, among climate drivers, warming emerged as the dominant amplifier, synergistically magnifying both MP-driven soil carbon accretion and respiratory turnover. Overall, this study elucidates the response patterns of the soil carbon-microbial system to MPs and climate change, offering an integrated perspective for understanding the carbon cycle under combined stressors and assessing related ecological risks.