Continental margin sediments are important sites of marine nitrogen cycling and potential contributors to atmospheric N₂O emissions. We employed trace‐level N₂O microsensors to measure vertical N₂O profiles at submillimeter resolutions in intact cores from outer continental margin sediments underlying the NE Pacific oxygen minimum zone. We used mathematical modeling to estimate depth‐dependent rates of N₂O production and fluxes to the overlying water along a transect of diminishing bottom water oxygen concentrations. Net sediment efflux was observed at all sites on the outer continental margin, with a mean value of 524 nmol m⁻² d⁻¹. N₂O efflux increased with decreased oxygen penetration depth in sediments. Enhanced N₂O production and efflux were obtained when outer continental shelf sediments were experimentally exposed to lower bottom‐water O₂ concentrations, to simulate upwelling conditions. Our results underline the need for further investigation of the drivers of N₂O production in continental margin sediments, and the relative importance of these environments to the global N₂O budget.

中文翻译：

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NE太平洋最低氧区下方的大陆边缘沉积物是水柱中一氧化二氮的来源

大陆边缘沉积物是海洋氮循环的重要场所，并且是大气中N ₂ O排放的潜在贡献者。我们采用了痕量N ₂ O微传感器，以亚毫米级分辨率测量了东北太平洋最小含氧量区域外大陆边缘沉积物的完整岩心中的垂直N ₂ O剖面。我们使用数学模型来估算随着深度不断减小的底部氧气浓度的横断面，N ₂ O产量和通向上层水的通量的深度依赖性速率。在外大陆边缘的所有位置均观测到净沉积物外排，平均值为524 nmol m ^-2 d ^-1。N ₂O流量随着沉积物中氧气渗透深度的减小而增加。当将外部大陆架沉积物实验性地暴露于较低的底部水O ₂浓度以模拟上升流条件时，可以提高N ₂ O的产生和流出。我们的结果强调需要进一步调查大陆边缘沉积物中N ₂ O产生的驱动因素，以及这些环境对全球N ₂ O预算的相对重要性。