The microplastics in nature water are important for the environmental fate of nitrous oxide (N₂O). This study investigated the influence and microbial mechanism of microplastic abundance to the N₂O flux in typical inflow rivers of Taihu lake. The microplastic abundance were in a range of 160–700 particles/m³ surface water, and 514–3018 particles/kg dry sediment. The highest percentage of microplastic color was transparent, significantly higher than other color (p<0.0001) in both surface water and sediment. The dominant microplastic size was 500–5000 μm in surface water, while size lower than 1000 μm was dominant in sediment. The microplastic abundance in sediment was negatively correlated with the concentration of suspended sediments (SPS) (p<0.05), Chl-a (p<0.05), NH₄⁺-N (p<0.05) and TP (p<0.01) in inflow river surface water. The dissolved N₂O concentration were 45.71–132.42 nmol/L, and the N₂O fluxes were 29.85–276.60 μmol/m²/d. The dissolved N₂O concentration was significantly correlated with the nirK abundance and nirK/nosZI ratio negatively (p<0.05), revealed that sediment nirK-type denitrification was the main driver of dissolved N₂O. Meanwhile, the N₂O flux (water-air interface) was significantly correlated with nosZI, napA, narG and nirS negatively, implied that nitrification and denitrification interaction in sediment is the main influence factor. The denitrification process in sediment was the main driven factor of N₂O releasing. Mantel-test shows that microplastic abundance in surface water was significantly correlated with nitrification (p = 0.001∼0.01) and denitrification (p = 0.01∼0.05) genera in water. The dominant denitrification microorganism was Dechloromonas in sediment and Flavobacterium in surface water. These results provided new insight into the fact that plastisphere which comprises microbial community on microplastic could affect the N₂O emission in aquatic system.

自然界水中的微塑料对一氧化二氮 (N ₂ O) 的环境归宿很重要。本研究探讨了微塑料丰度对太湖典型流入河流N _{2 O通量的影响及其微生物机制。}微塑料丰度在 160–700 个颗粒/m ³地表水和 514–3018 个颗粒/kg 干沉积物中。微塑料颜色透明比例最高，显着高于其他颜色（p<0.0001) 在地表水和沉积物中。地表水中占主导地位的微塑料尺寸为 500-5000 μm，而沉积物中小于 1000 μm 的尺寸占优势。沉积物中微塑料丰度与悬浮沉积物（SPS）（p <0.05）、Chl-a（p <0.05）、NH ₄ ⁺ -N（p <0.05）和TP（p <0.01）浓度呈负相关。流入河流地表水。溶解的N ₂ O浓度为45.71~132.42 nmol/L，N ₂ O通量为29.85~276.60 μmol/m ² /d。溶解的 N ₂ O 浓度与nirK丰度和nirK / nosZI比值负（p <0.05），表明沉积物nirK型反硝化是溶解 N ₂ O 的主要驱动力。同时，N _{2 O 通量（水-空气界面）与}nosZI、napA、narG显着相关和nirS 为负，暗示沉积物中硝化和反硝化相互作用是主要影响因素。沉积物反硝化过程是N ₂ O释放的主要驱动因素。Mantel 检验表明，地表水中的微塑料丰度与硝化作用（p  = 0.001∼0.01）和反硝化作用（p = 0.01∼0.05) 属在水中。主要的反硝化微生物是沉积物中的脱氯单胞菌和地表水中的黄杆菌。这些结果提供了新的认识，即在微塑料上包含微生物群落的塑料圈可能会影响水生系统中的 N ₂ O 排放。