Methane (CH₄) emissions from wetland ecosystems are controlled by redox conditions in the soil, which are currently underrepresented in Earth system models. Plant-mediated radial oxygen loss (ROL) can increase soil O₂ availability, affect local redox conditions, and cause heterogeneous distribution of redox-sensitive chemical species at the root scale, which would affect CH₄ emissions integrated over larger scales. In this study, we used a subsurface geochemical simulator (PFLOTRAN) to quantify the effects of incorporating either spatially homogeneous ROL or more complex heterogeneous ROL on model predictions of porewater solute concentration depth profiles (dissolved organic carbon, methane, sulfate, sulfide) and column integrated CH₄ fluxes for a tidal coastal wetland. From the heterogeneous ROL simulation, we obtained 18% higher column averaged CH₄ concentration at the rooting zone but 5% lower total CH₄ flux compared to simulations of the homogeneous ROL or without ROL. This difference is because lower CH₄ concentrations occurred in the same rhizosphere volume that was directly connected with plant-mediated transport of CH₄ from the rooting zone to the atmosphere. Sensitivity analysis indicated that the impacts of heterogeneous ROL on model predictions of porewater oxygen and sulfide concentrations will be more important under conditions of higher ROL fluxes or more heterogeneous root distribution (lower root densities). Despite the small impact on predicted CH₄ emissions, the simulated ROL drastically reduced porewater concentrations of sulfide, an effective phytotoxin, indicating that incorporating ROL combined with sulfur cycling into ecosystem models could potentially improve predictions of plant productivity in coastal wetland ecosystems.

湿地生态系统的甲烷 (CH ₄ ) 排放受土壤中的氧化还原条件控制，目前在地球系统模型中代表性不足。植物介导的径向氧损失（ROL）可以增加土壤 O ₂ 的有效性，影响局部氧化还原条件，并导致根部氧化还原敏感化学物质的不均匀分布，从而影响 CH ₄ 通量。通过非均相 ROL 模拟，与均相 ROL 或无 ROL 的模拟相比，我们在生根区获得的柱平均 CH ₄ 浓度高出 18%，但总 CH ₄ 通量低 5% 。这种差异是因为较低的 CH ₄ 浓度发生在相同的根际体积中，这与植物介导的 CH ₄ 从生根区到大气的运输直接相关。敏感性分析表明，在ROL通量较高或根系分布更加不均匀（根密度较低）的条件下，非均质ROL对孔隙水氧和硫化物浓度模型预测的影响将更为重要。 尽管对预测的 CH ₄ 排放影响很小，但模拟的 ROL 大大降低了孔隙水中硫化物（一种有效的植物毒素）的浓度，表明将 ROL 与硫循环结合到生态系统模型中可能会改善对沿海植物生产力的预测湿地生态系统。