Modern observations indicate that variations in marine phytoplankton stoichiometry correlate with the boundaries of major surface waters. For example, phytoplankton in the oligotrophic subtropical gyres typically have much higher C:N:P ratios (i.e., higher C:P and higher N:P ratios) than those in eutrophic upwelling regions and polar regions. Such a spatial pattern points to nutrient availability as a key environmental driver of stochiometric flexibility. Environmental dependence of phytoplankton C:N:P opens unexplored possibilities for modifying the strength of the biological pump under different climate conditions. Here we present a power law formulation of C:N:P flexibility that is driven by nutrients, temperature, and light. We embed the formulation in a global ocean carbon cycle model with multiple phytoplankton types and explore biogeochemical implications under glacial conditions. We find three key controls on export C:N:P ratio: phytoplankton physiology and community structure as well as the balance in regional production at the global level. Glacial inputs of iron and sea ice expansion are important modifiers of these three controls. We also find that global export C:N:P increases substantially under glacial conditions, and this strongly buffers global carbon export against decrease and draws down approximately 20 μatm of atmospheric CO₂. These results point to the importance of including phytoplankton C:N:P flexibility in a mix of mechanisms that drive atmospheric CO₂ over glacial‐interglacial time scale. Finally, our simulations indicate decoupling of nutrients, which may provide a resolution to the longstanding disagreement regarding nutrient utilization in the glacial Southern Ocean derived from different nutrient proxies.

中文翻译：

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冰川条件下柔性浮游植物C：N：P的碳出口缓冲和CO2吸收

现代观测表明，海洋浮游植物化学计量的变化与主要地表水的边界相关。例如，贫营养亚热带回旋中的浮游植物通常比富营养化上升区和极地区的浮游植物具有更高的C：N：P比（即更高的C：P和更高的N：P比）。这样的空间格局表明养分的可利用性是化学计量灵活性的关键环境驱动因素。浮游植物C：N：P对环境的依赖性为在不同气候条件下改变生物泵的强度提供了未探索的可能性。在这里，我们介绍由营养素，温度和光线驱动的C：N：P柔性的幂律公式。我们将制剂嵌入具有多种浮游植物类型的全球海洋碳循环模型中，并探索在冰川条件下的生物地球化学意义。我们发现出口C：N：P比率的三个关键控制因素：浮游植物的生理和群落结构以及全球范围内区域生产的平衡。铁和海冰膨胀的冰川投入是这三个控制的重要调节器。我们还发现，在冰河条件下，全球出口C：N：P显着增加，这极大地缓冲了全球碳出口的下降，并减少了约20μatm的大气CO 铁和海冰膨胀的冰川投入是这三个控制的重要调节器。我们还发现，在冰河条件下，全球出口C：N：P显着增加，这极大地缓冲了全球碳出口的下降，并减少了约20μatm的大气CO 铁和海冰膨胀的冰川投入是这三个控制的重要调节器。我们还发现，在冰河条件下，全球出口C：N：P显着增加，这极大地缓冲了全球碳出口的下降，并减少了约20μatm的大气CO₂。这些结果表明，将浮游植物C：N：P的灵活性包括在冰川-冰川间时间尺度内驱动大气CO ₂的各种机制中非常重要。最后，我们的模拟表明养分的脱钩，这可能为长期以来关于来自不同养分代理的冰川在南大洋中养分利用的分歧提供了解决方案。