College of Environmental Science and Engineering, Zhejiang Gongshang University, Hangzhou, 310018, China.
Key Laboratory of Pollution Exposure and Health Intervention of Zhejiang Province, Interdisciplinary Research Academy (IRA), Zhejiang Shuren University, Hangzhou, 310015, China.
Chemosphere. 2022 Dec;309(Pt 1):136642. doi: 10.1016/j.chemosphere.2022.136642. Epub 2022 Oct 3.
Graphene oxide (GO) has been widely used in many applications due to its excellent properties. Given the extensive production and use of this nanomaterial, its release into the environment is inevitable. However, little is known about the effects of GO on microbial nitrogen transformation and the related processes after GO enters the soil environment. The present study showed that GO significantly reduced soil microbial biomass and caused a decline in microbial diversity after the soils were subjected to various GO concentrations (10, 100, and 1000 mg kg) for 4 months. Among them, the abundances of nitrogen transformation related bacteria such as Firmicutes, Nitrospirota, Proteobacteria, Planctomycetota, and Cyanobacteria were significantly decreased with GO incubation. Among the enzymes that are related to nitrogen transformation, nitrate reductase was the most sensitive even at low concentrations of GO, followed by ammonia monooxygenase and urease, which were reduced by 13-31%, 5-26%, and 9-19% respectively, than those of the control. We found that high concentrations of GO significantly increased the retention of soil urea by 32-59%, and the contents of ammonium and nitrate were 22-28% and 55-69% lower compared to those of the control, respectively. Moreover, the response of most of the indicators in the above process to multilayer GO was more significant than that to single layer GO. Overall, this study provides new insights into the comprehensive understanding of GO's impacts on the soil nitrogen cycle.
氧化石墨烯（GO）由于其优异的性能而被广泛应用于许多领域。鉴于这种纳米材料的广泛生产和使用，其释放到环境中是不可避免的。然而，对于 GO 进入土壤环境后对微生物氮转化及其相关过程的影响知之甚少。本研究表明，GO 在土壤中经过 4 个月的不同浓度（10、100 和 1000 mg/kg）处理后，显著降低了土壤微生物生物量，导致微生物多样性下降。其中，Firmicutes、Nitrospirota、Proteobacteria、Planctomycetota 和 Cyanobacteria 等氮转化相关细菌的丰度随着 GO 的孵育而显著降低。在与氮转化相关的酶中，硝酸盐还原酶对 GO 的敏感性最高，即使在低浓度的 GO 下，其活性也降低了 13-31%，而氨单加氧酶和脲酶的活性分别降低了 5-26%和 9-19%。我们发现，高浓度的 GO 显著增加了土壤尿素的保留量，分别增加了 32-59%，而铵和硝酸盐的含量分别比对照降低了 22-28%和 55-69%。此外，上述过程中大多数指标对多层 GO 的响应比单层 GO 更显著。总的来说，本研究为全面了解 GO 对土壤氮循环的影响提供了新的见解。
