Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085, China; University of Chinese Academy of Science, Beijing, 100049, China.
Key Laboratory of Geographic Information Science (Ministry of Education), School of Geographic Sciences, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China; State Key Laboratory of Estuarine and Coastal Research, East China Normal University, 500 Dongchuan Road, Shanghai, 200241, China.
Water Res. 2024 Jul 1;258:121761. doi: 10.1016/j.watres.2024.121761. Epub 2024 May 9.
Anthropogenic activities significantly impact the elemental cycles in aquatic ecosystems, with the N-cycling playing a critical role in potential nutrient turnover and substance cycling. We hypothesized that measures to prevent COVID-19 transmission profoundly altered the nitrogen cycle in riverine ecosystems. To investigate this, we re-analyzed metagenomic data and identified 60 N-cycling genes and 21 host metagenomes from four urban reaches (one upstream city, Wuhan, and two downstream cities) along the Yangtze River. Our analyses revealed a marked decrease in the abundance of bacterial ammonia monooxygenase genes, as well as in the host, ammonia-oxidizing autotrophic Nitrosomonas, followed by a substantial recovery post-pandemic. We posited that discharge of sodium hypochlorite (NaOCl) disinfectant may be a primary factor in the reduction of N-cycling process. To test this hypothesis, we exposed pure cultures of Nitrosomonas europaea to NaOCl to explore the microbial stress response. Results indicated that NaOCl exposure rapidly compromised the cell structure and inhibited ammonia oxidation of N. europaea, likely due to oxidative stress damage and reduced expression of nitrogen metabolism-related ammonia monooxygenase. Using the functional tagging technique, we determined that NaOCl directly destroyed the ammonia monooxygenase protein and DNA structure. This study highlights the negative impacts of chlorine disinfectants on the function of aquatic ecosystems and elucidates potential mechanisms of action.
人为活动显著影响水生生态系统的元素循环，其中氮循环在潜在养分转化和物质循环中起着关键作用。我们假设，预防 COVID-19 传播的措施会深刻改变河流生态系统的氮循环。为了研究这一点，我们重新分析了宏基因组数据，并从长江四个城市河段（一个上游城市武汉和两个下游城市）中鉴定出 60 个氮循环基因和 21 个宿主宏基因组。我们的分析表明，细菌氨单加氧酶基因以及宿主氨氧化自养硝化菌的丰度明显下降，随后在大流行后出现了大量恢复。我们假设次氯酸钠（NaOCl）消毒剂的排放可能是氮循环过程减少的一个主要因素。为了验证这一假设，我们将纯培养的硝化单胞菌暴露于次氯酸钠中，以探索微生物的应激反应。结果表明，次氯酸钠暴露迅速破坏了硝化单胞菌的细胞结构，并抑制了其氨氧化，这可能是由于氧化应激损伤和与氮代谢相关的氨单加氧酶表达减少。使用功能标记技术，我们确定次氯酸钠直接破坏了氨单加氧酶的蛋白质和 DNA 结构。本研究强调了氯消毒剂对水生生态系统功能的负面影响，并阐明了其潜在的作用机制。
