A past global synthesis of marine particulate organic matter (POM) suggested latitudinal variation in the ratio of surface carbon (C): nitrogen (N): phosphorus (P). However, this synthesis relied on compiled datasets that may have biased the observed pattern. To demonstrate latitudinal shifts in surface C:N:P, we combined hydrographic and POM observations from 28°N to 69°S in the eastern Pacific Ocean (GO-SHIP line P18). Both POM concentrations and ratios displayed distinct biome-associated changes. Surface POM concentrations were relatively low in the North Pacific subtropical gyre, increased through the Equatorial Pacific, were lowest in the South Pacific subtropical gyre, and increased through the Southern Ocean. Stoichiometric elemental ratios were systematically above Redfield proportions in warmer regions. However, C:P and N:P gradually decreased across the Southern Ocean despite an abundance of macro-nutrients. Here, a size-fraction analysis of POM linked increases in the proportion of large plankton to declining ratios. Subsurface N* values support the hypothesis that accumulated remineralization products of low C:P and N:P exported POM helps maintain the Redfield Ratio of deep nutrients. We finally evaluated stoichiometric models against observations to assess predictive accuracy. We attributed the failure of all models to their inability to capture shifts in the specific nature of nutrient limitation. Our results point to more complex linkages between multinutrient limitation and cellular resource allocation than currently parameterized in models. These results suggest a greater importance of understanding the interaction between the type of nutrient limitation and plankton diversity for predicting the global variation in surface C:N:P.

中文翻译：

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链接东太平洋海洋水文学中的纬度梯度和元素化学计量学

过去对海洋颗粒有机物（POM）的全球综合研究表明，表面碳（C）：氮（N）：磷（P）的比例存在纬度变化。但是，此合成依赖于可能偏向观察模式的已编译数据集。为了证明表面C：N：P的纬度变化，我们结合了东太平洋从28°N到69°S的水文和POM观测结果（GO-SHIP行P18）。POM浓度和比率均显示出明显的生物群落相关变化。在北太平洋亚热带回旋中，表面POM浓度相对较低，在赤道太平洋中有所增加，在南太平洋亚热带回旋中最低，而通过南大洋则有所增加。在较暖的地区，化学计量元素比率系统地高于雷德菲尔德比率。但是，C：P和N：尽管有大量的养分，但整个大洋中的磷逐渐下降。在这里，链接的POM的尺寸分数分析表明，大浮游生物的比例与下降的比例增加了。地下N *值支持以下假设：低C：P和N：P出口POM的累积再矿化产物有助于维持深层营养物的Redfield比率。我们最终根据观察结果评估了化学计量模型，以评估预测准确性。我们将所有模型的失败归因于它们无法捕捉到养分限制的特定性质的变化。我们的结果表明，与当前模型中参数化设置相比，多种营养素限制与细胞资源分配之间的联系更为复杂。