Soil moisture-dependent tire wear particles aging processes shift soil microbial communities and elevated nitrous oxide emission on drylands

Tire wear particles (TWPs) have been an emerging threat to the soil ecosystem, while impact of the TWPs aging on soil microbial communities remains poorly understood. This study investigated the dynamic responses of soil microbial communities to the TWPs aging under both wet and flooded conditions. We found that different soil moisture conditions resulted in distinct microbial community structures. Soil bacteria were more sensitive to wet conditions, while soil fungi were more sensitive to flooded conditions. The family Symbiobacteraceae was predominant in the TWP-sphere under both wet and flooded conditions after 60 days, followed by Brevibacillaceae. Notably, we observed that TWPs input significantly increased nitrous oxide (N₂O) emission from dryland soil. Several taxa including Cyanobacteriales, Blastocatellaceae and Pyrinomonadaceae were identified as TWP-biomarkers in soils and potentially played significant roles in N₂O emissions from drylands. Their responses to the TWPs input correlated closely with changes in the relative abundance of genes involved in ammonia oxidation (amoA/B), nitrite reduction (nirS/K) and N₂O reduction (nosZ) in drylands. Our results demonstrate that soil moisture-dependent TWP aging influences N₂O emission by altering both the associated microbial communities and the relevant genes.