State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China; Shanghai Academy of Landscape Architecture Science and Planning, Shanghai 200232, China.
School of Geographic Sciences, East China Normal University, Shanghai 200241, China; Department of Urban Planning and Design, Faculty of Architecture, The University of Hong Kong, Hong Kong, China.
J Hazard Mater. 2024 Aug 15;475:134893. doi: 10.1016/j.jhazmat.2024.134893. Epub 2024 Jun 11.
Nitrite/nitrate-dependent anaerobic methane oxidation (n-DAMO) is an important methane (CH) consumption and nitrogen (N) removal pathway in estuarine and coastal wetlands. Antibiotic contamination is known to affect microbially mediated processes; however, its influences on n-DAMO and the underlying molecular mechanisms remain poorly understood. In the present study, using CH tracer method combined with molecular techniques, we investigated the responses of n-DAMO microbial abundance, activity, and the associated microbial community composition to sulfamethazine (SMT, a sulfonamide antibiotic, with exposure concentrations of 0.05, 0.5, 5, 20, 50, and 100 µg L). Results showed that the effect of SMT exposure on n-DAMO activity was dose-dependent. Exposure to SMT at concentrations of up to 5 µg L inhibited the potential n-DAMO rates (the average rates of nitrite- and nitrate-DAMO decreased by 92.9 % and 79.2 % relative to the control, respectively). In contrast, n-DAMO rates tended to be promoted by SMT when its concentration increased to 20-100 µg L (the average rates of nitrite- and nitrate-DAMO increased by 724.1 % and 630.1 % relative to the low-doses, respectively). Notably, low-doses of SMT suppressed nitrite-DAMO to a greater extent than nitrate-DAMO, indicating that nitrite-DAMO was more sensitive to SMT than nitrate-DAMO. Molecular analyses suggest that the increased n-DAMO activity under high-doses SMT exposure may be driven by changes in microbial communities, especially because of the promotion of methanogens that provide more CH to n-DAMO microbes. Moreover, the abundances of n-DAMO microbes at high SMT exposure (20 and 50 µg L) were significantly higher than that at low SMT exposure (0.05-5 µg L). These results advance our understanding of the ecological effects of SMT on carbon (C) and N interactions in estuarine and coastal wetlands.
亚硝酸盐/硝酸盐依赖型厌氧甲烷氧化（n-DAMO）是河口和沿海湿地中一种重要的甲烷（CH）消耗和氮（N）去除途径。已知抗生素污染会影响微生物介导的过程；然而，其对 n-DAMO 的影响及其潜在的分子机制仍知之甚少。在本研究中，我们使用 CH 示踪法结合分子技术，研究了磺胺甲噁唑（SMT，一种磺胺类抗生素，暴露浓度为 0.05、0.5、5、20、50 和 100 µg L）对 n-DAMO 微生物丰度、活性和相关微生物群落组成的响应。结果表明，SMT 暴露对 n-DAMO 活性的影响是剂量依赖性的。暴露于 SMT 的浓度高达 5 µg L 时，抑制了潜在的 n-DAMO 速率（相对于对照，亚硝酸盐和硝酸盐-DAMO 的平均速率分别降低了 92.9%和 79.2%）。相反，当 SMT 浓度增加到 20-100 µg L 时，n-DAMO 速率趋于被促进（相对于低剂量，亚硝酸盐和硝酸盐-DAMO 的平均速率分别增加了 724.1%和 630.1%）。值得注意的是，低剂量的 SMT 对亚硝酸盐-DAMO 的抑制作用大于硝酸盐-DAMO，表明亚硝酸盐-DAMO 对 SMT 的敏感性高于硝酸盐-DAMO。分子分析表明，高剂量 SMT 暴露下 n-DAMO 活性的增加可能是由微生物群落的变化驱动的，特别是由于促进了提供更多 CH 给 n-DAMO 微生物的产甲烷菌。此外，在高 SMT 暴露（20 和 50 µg L）下 n-DAMO 微生物的丰度明显高于低 SMT 暴露（0.05-5 µg L）。这些结果提高了我们对 SMT 对河口和沿海湿地碳（C）和 N 相互作用的生态影响的认识。
