Interactions between dissolved organic matters and microbial community is regulated by microplastics and heat waves

The relationship between dissolved organic matter (DOM) cycling and microbial communities is complex and bidirectional, which is crucial to delineate the global carbon cycling process. The effects of microplastic (MP) pollution and heatwaves (HWs) on the association between DOM and microbial community composition and diversity remains poorly characterized. Here we found that DOM could explain 43.17% of the variation of microbial community. Humic acid-like DOM with high molecular weight and aromatic properties produced a highly diverse microbial community. MPs could affect microbial community succession and inhibit the bioavailability of DOM. HWs promoted the utilization of MPs-derived DOM by microorganisms and drove the effective utilization of refractory carbon in rivers. Overall, our findings advance our biological understanding of aquatic carbon biogeochemical cycling in the context of climate change.