Microplastics Generate Less Mineral Protection of Soil Carbon and More CO2 Emissions

Microplastic pollution in terrestrial ecosystems threatens to destabilize large soil carbon stocks that help to mitigate climate change. Carbon-based substrates can release from microplastics and contribute to terrestrial carbon pools, but how these emerging organic compounds influence carbon mineralization and sequestration remains unknown. Here, microcosm experiments are conducted to determine the bioavailability of microplastic-derived dissolved organic matter (MP-DOM) in soils and its contribution to mineral-associated carbon pool. The underlying mechanisms are identified by estimating its spectroscopic and molecular signatures and comparing its sorption properties on model minerals with natural organic matter (NOM). The results show that MP-DOM leads to 21-576% higher CO