Linking a Latitudinal Gradient in Ocean Hydrography and Elemental Stoichiometry in the Eastern Pacific Ocean
Linking a Latitudinal Gradient in Ocean Hydrography and Elemental Stoichiometry in the Eastern Pacific Ocean
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DOI：
10.1029/2020gb006622
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发表时间：
2021-05-01
影响因子：
5.2
通讯作者：
Martiny, Adam C.
中科院分区：
文献类型：
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作者：
Lee, Jenna A.;Garcia, Catherine A.;Martiny, Adam C.
过去的全球海洋颗粒有机物（POM）的合成表明，表面碳（C）：氮（N）：磷（P）的比例的纬度变化。然而，这种综合依赖于汇编的数据集，可能会使观察到的模式产生偏差。为了证明表面C：N：P的纬向变化，我们结合了东太平洋（GO-SHIP线P18）从北纬28度到南纬69度的水文和POM观测。POM的浓度和比率都显示出明显的生物群系相关变化。在北太平洋副热带环流中，POM浓度相对较低，通过赤道太平洋增加，在南太平洋副热带环流中最低，通过南大洋增加。化学计量元素比系统高于Redfield比例在温暖的地区。然而，C：P和N：P逐渐减少整个南大洋，尽管丰富的宏观营养盐。在这里，POM的粒度分析将大型浮游生物比例的增加与比例的下降联系起来。次表层N* 值支持这一假设，即低C：P和N：P输出POM的累积矿化产物有助于维持深层营养盐的Redfield比率。最后，我们评估了化学计量模型对观察，以评估预测的准确性。我们将所有模型的失败归因于它们无法捕捉营养限制的特定性质的变化。我们的研究结果表明，多营养素限制和细胞资源分配之间的联系比目前在模型中参数化的更为复杂。这些结果表明，了解营养盐限制类型和浮游生物多样性之间的相互作用对于预测全球表层C：N：P的变化具有重要意义。
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 degrees N to 69 degrees 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.