The plastic-carbon-climate nexus: Carbon sequestration, microbial adaptation, and land use solutions for a warming microplastics-contaminated world

Microplastics (MPs) affect biogeochemical cycles, but the mechanisms remain unclear due to uncertainties in soil properties and microbial interactions. This paper reviews the latest advances in how increasing MPs pollution alters soil carbon pool stability and microbial community phylogeny, thereby regulating the carbon cycle. In addition to the direct microbial utilization of MPs derivatives, changes in the oxygen environment and electron transport facilitate the mineralization of primary organic matter in soil. Complex agglomerates of MPs, minerals, and organic matter help mitigate this priming effect. Moreover, the plastisphere ecology enriches carbon-turnover microorganisms and regulates functional gene expression involved in carbon cycling, possibly inducing microbial adaptive evolution through different mechanisms. This leads to ecological niche reconstruction and further regulation of carbon turnover interactions within communities. Climate warming and MPs pollution form a positive feedback loop, posing substantial ecological risks. Meta-analysis indicates that targeted land-use management can effectively mitigate these risks by reducing MPs pollution. Future research should focus on MPs ecological risk classification, carbon turnover response thresholds, microbial interactions, the ecological risks of degradable plastics, and in situ monitoring techniques to promote sustainable soil management and support global carbon neutrality goals.