Gong Jiang-Chen, Li Bing-Han, Hu Jing-Wen, Li Pei-Feng, Liu Qian, Yang Gui-Peng, Liu Chun-Ying
Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China; Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266237, China.
Frontiers Science Center for Deep Ocean Multispheres and Earth System, Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, and College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100, China.
Water Res. 2023 Dec 1;247:120770. doi: 10.1016/j.watres.2023.120770. Epub 2023 Oct 21.
Intertidal wetland sediments are an important source of atmospheric nitrogen oxides (NO), but their contribution to the global NO budget remains unclear. In this work, we conducted year-round and diurnal observations in the intertidal wetland of Jiaozhou Bay to explore their regional source-sink patterns and influence factors on NO emissions (initially in the form of nitric oxide) and used a dynamic soil reactor to further extend the mechanisms underlying the tidal pulse of nitric oxide (NO) observed in our investigations. The annual fluxes of NO in the vegetated wetland were significantly higher than those in the wetland without vegetation. Their annual variations could be attributed to changes in temperature and the amount of organic carbon in the sediment, which was derived from vegetated plants and promoted the carbon-nitrogen cycle. Anaerobic denitrifiers had advantages in the intertidal wetland sediment and accounted for the major NO production (63.8 %) but were still limited by nitrite and nitrate concentrations in the sediment. Moreover, the tidal pulse was likely a primary driver of NO emissions from intertidal wetlands over short periods, which was not considered in previous investigations. The annual NO exchange flux considering the tide pulse contribution (8.93 ± 1.72 × 10 kg N ha yr) was significantly higher than that of the non-pulse period (4.14 ± 1.13 × 10 kg N ha yr) in our modeling result for the fluxes over the last decade. Therefore, the current measurement of NO fluxes underestimated the actual gas emission without considering the tidal pulse.
潮间带湿地沉积物是大气氮氧化物（NO）的重要来源，但其对全球NO收支的贡献仍不清楚。在本研究中，我们在胶州湾潮间带湿地进行了全年和昼夜观测，以探究其区域源汇模式及NO排放（初始形式为一氧化氮）的影响因素，并使用动态土壤反应器进一步拓展我们在调查中观测到的一氧化氮（NO）潮汐脉冲背后的机制。植被覆盖湿地中NO的年通量显著高于无植被湿地。其年变化可归因于温度和沉积物中有机碳含量的变化，这些有机碳来自植被植物，促进了碳氮循环。厌氧反硝化菌在潮间带湿地沉积物中具有优势，是NO产生的主要贡献者（63.8%），但仍受沉积物中亚硝酸盐和硝酸盐浓度的限制。此外，潮汐脉冲可能是潮间带湿地短期内NO排放的主要驱动因素，而这在以往的调查中未被考虑。在我们对过去十年通量的模拟结果中，考虑潮汐脉冲贡献的年NO交换通量（8.93±1.72×10 kg N ha yr）显著高于非脉冲期（4.14±1.13×10 kg N ha yr）。因此，当前对NO通量的测量在未考虑潮汐脉冲的情况下低估了实际气体排放。
