Key Laboratory of Geographic Information Science (Ministry of Education), East China Normal University, Shanghai 200241, China; School of Geographic Sciences, East China Normal University, 500 Dongchuan Road, Minhang District, Shanghai 200241, China.
Key Laboratory of Geographic Information Science (Ministry of Education), East China Normal University, Shanghai 200241, China; School of Geographic Sciences, East China Normal University, 500 Dongchuan Road, Minhang District, Shanghai 200241, China; State Key Laboratory of Estuarine and Coastal Research, Yangtze Delta Estuarine Wetland Ecosystem Observation and Research Station, Ministry of Education & Shanghai, East China Normal University, 500 Dongchuan Road, Minhang District, Shanghai 200241, China.
Water Res. 2024 Sep 1;261:122041. doi: 10.1016/j.watres.2024.122041. Epub 2024 Jul 3.
Acidification of coastal waters, synergistically driven by increasing atmospheric carbon dioxide (CO) and intensive land-derived nutrient inputs, exerts significant stresses on the biogeochemical cycles of coastal ecosystem. However, the combined effects of anthropogenic nitrogen (N) inputs and aquatic acidification on nitrification, a critical process of N cycling, remains unclear in estuarine and coastal ecosystems. Here, we showed that increased loading of ammonium (NH) in estuarine and coastal waters alleviated the inhibitory effect of acidification on nitrification rates but intensified the production of the potent greenhouse gas nitrous oxide (NO), thus accelerating global climate change. Metatranscriptomes and natural NO isotopic signatures further suggested that the enhanced emission of NO may mainly source from hydroxylamine (NHOH) oxidation rather than from nitrite (NO) reduction pathway of nitrifying microbes. This study elucidates how anthropogenic N inputs regulate the effects of coastal acidification on nitrification and associated NO emissions, thereby enhancing our ability to predict the feedbacks of estuarine and coastal ecosystems to climate change and human perturbations.
沿海水域酸化受大气二氧化碳（CO）不断增加和陆地营养物输入增强的协同驱动，对沿海生态系统的生物地球化学循环造成了重大压力。然而，人为氮（N）输入和水生酸化对硝化作用（氮循环的关键过程）的综合影响在河口和沿海生态系统中尚不清楚。在这里，我们表明，河口和沿海水中铵（NH）负荷的增加缓解了酸化对硝化速率的抑制作用，但加剧了强温室气体一氧化二氮（NO）的产生，从而加速了全球气候变化。宏转录组和天然 NO 同位素特征进一步表明，NO 的增强排放可能主要源自羟胺（NHOH）氧化，而不是硝化微生物的亚硝酸盐（NO）还原途径。本研究阐明了人为 N 输入如何调节沿海酸化对硝化作用及相关 NO 排放的影响，从而提高了我们预测河口和沿海生态系统对气候变化和人为干扰反馈的能力。
