The accumulation of Ag₂S in agricultural soil via application of Ag-containing sludge potentially affects the functioning of soil microorganisms and earthworms (EWs) due to the strong antimicrobial properties of Ag. This study examined the effects of Ag₂S nanoparticles (Ag₂S-NPs) on the EW-mediated (Eisenia fetida and Pontoscolex corethrurus) soil N cycle. We used 16S rRNA gene-based sequencing and quantitative polymerase chain reaction to examine the bacterial community and nitrification/denitrification-related gene abundance. The presence of either EWs or Ag significantly increased denitrification and N₂O emissions. However, the addition of Ag₂S to EW-inhabited soil reduced N₂O emissions by 14–33%. Furthermore, Ag₂S caused a low-dose stimulation but a high-dose inhibition to N₂O flux from the EW gut itself. Accordingly, an increase in Ag in the EW gut caused a decrease in the relative abundance of denitrifiers in both the soil and the gut, especially for the dominant genus Bacillus. Ag₂S also decreased the copy numbers of nitrification gene (nxrB) and denitrification genes (napA, nirS, and nosZ) in EW gut, leading to the observed decrease in N₂O emissions. Collectively, applying Ag₂S-containing sludge disturbs the denitrification function of the EW gut microbiota and the cycling of N in soil-based systems.

中文翻译：

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硫化银纳米颗粒通过抑制worm肠中的反硝化作用来减少一氧化二氮的排放。

由于银的强抗菌特性，通过施用含银污泥在农业土壤中积累的Ag ₂ S可能会影响土壤微生物和earth（EWs）的功能。这项研究检查了Ag ₂ S纳米颗粒（Ag ₂ S-NPs）对EW介导的（Eisenia fetida和Pontoscolex corethrurus）土壤N循环的影响。我们使用了基于16S rRNA基因的测序和定量聚合酶链反应来检查细菌群落和硝化/反硝化相关的基因丰度。EW或Ag的存在显着增加了反硝化作用和N ₂ O排放。但是，添加Ag ₂从S到EW居住的土壤可使N ₂ O排放减少14–33％。此外，Ag ₂ S引起低剂量刺激，但对EW肠自身对N ₂ O通量的抑制作用较大。因此，EW肠道中Ag的增加导致土壤和肠道中反硝化剂的相对丰度降低，特别是对于优势芽孢杆菌属而言。Ag ₂ S还降低了EW肠道中硝化基因（nxrB）和反硝化基因（napA，nirS和nosZ）的拷贝数，从而导致N ₂ O排放量减少。集体施用Ag ₂含S的污泥会扰乱EW肠道菌群的反硝化功能以及基于土壤的系统中N的循环。