Transport zonation limits coupled nitrification-denitrification in permeable sediments.
Transport zonation limits coupled nitrification-denitrification in permeable sediments.
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DOI：
10.1021/es403318x
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发表时间：
2013-11
影响因子：
11.4
通讯作者：
Adam J. Kessler;R. Glud;M. Cardenas;Perran L. M. Cook
中科院分区：
文献类型：
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作者：
Adam J. Kessler;R. Glud;M. Cardenas;Perran L. M. Cook
渗透性沉积物（包括潜流带）中复杂的多维平流输运过程，使其地球化学过程的测量变得困难。对于氮循环尤其如此，其涉及几个耦合的氧化还原敏感性反应。为了提供详细的洞察氨化作用，硝化作用和反硝化作用之间的耦合在静止的沙波纹，我们结合了扩散平衡薄层（DET）凝胶技术与计算反应传输地球化学模型。前者提供了高分辨率的二维分布的NO3（-）和（15）N-N2气体。测量的二维配置文件与计算模型模拟，显示了深池的氮气形成，并平流到涟漪峰下方的表面。这些数据的进一步同位素配对计算表明，耦合硝化反硝化作用是严重限制在可渗透的沉积物，因为流动和运输场限制好氧和缺氧孔隙水之间的相互作用。该方法允许新的详细了解地下反硝化区在复杂的渗透性沉积物。
Measurement of biogeochemical processes in permeable sediments (including the hyporheic zone) is difficult because of complex multidimensional advective transport. This is especially the case for nitrogen cycling, which involves several coupled redox-sensitive reactions. To provide detailed insight into the coupling between ammonification, nitrification and denitrification in stationary sand ripples, we combined the diffusion equilibrium thin layer (DET) gel technique with a computational reactive transport biogeochemical model. The former approach provided high-resolution two-dimensional distributions of NO3(-) and (15)N-N2 gas. The measured two-dimensional profiles correlate with computational model simulations, showing a deep pool of N2 gas forming, and being advected to the surface below ripple peaks. Further isotope pairing calculations on these data indicate that coupled nitrification-denitrification is severely limited in permeable sediments because the flow and transport field limits interaction between oxic and anoxic pore water. The approach allowed for new detailed insight into subsurface denitrification zones in complex permeable sediments.