Feedbacks between N2 fixation and denitrification in a non-Redfield Earth system model and impacts on the oceanic fixed-N inventory in a changing climate

海洋氮气固定和反硝化作用如何以及有多强相互耦合，是理解和预测气候变化中海洋3号清单和生物泵的关键。虽然目前的模拟工作预测了氮气固定和反硝化之间的强耦合，但最近开发的基于最优化的非Redfield生态系统模型(OPEM)与UVic-ESCM耦合显示它们之间的耦合要弱得多。该项目旨在确定控制这种耦合的因素和机制，并了解这种耦合在不同气候环境下可能发生的变化。新模型将应用于工业化前、最后一次冰川最大值和现在的条件，以海洋氮清单和生物碳泵对不同气候状态的敏感度来评估该模型。最终目标是更好地了解对海洋氮清单的控制，并改进对未来海洋生物地球化学及其对大气二氧化碳的影响的预测。

How and how strongly marine N2 fixation and denitrification are coupled to each other is key to understanding and projecting the oceanic NO3 – inventory and biological pump in a changing climate. While current modeling works predict a strong coupling between N2 fixation and denitrification, the recently developed optimality-based non-Redfield ecosystem model (OPEM) coupled to the UVic- ESCM shows much weaker coupling between them. This project aims to identify those factors and mechanisms that control the coupling, and to understand how the coupling might change in different climate settings. The new model will be applied to pre-industrial, the last glacial maximum and present-day conditions to evaluate the model in terms of the sensitivity of the oceanic nitrogen inventory and the biological carbon pump to different climate states. The ultimate goal is to better understand the controls on the oceanic nitrogen inventory and to provide improved projections of future marine biogeochemistry and its impacts on atmospheric pCO2.