The Southern Ocean silicon trap: Data-constrained estimates of regenerated silicic acid, trapping efficiencies, and global transport paths
The Southern Ocean silicon trap: Data-constrained estimates of regenerated silicic acid, trapping efficiencies, and global transport paths
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DOI：
10.1002/2013jc009356
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发表时间：
2014-01-01
影响因子：
3.6
通讯作者：
Matear, Richard
中科院分区：
文献类型：
--
作者：
Holzer, Mark;Primeau, Francois W.;Matear, Richard
我们分析了嵌入数据同化稳定海洋环流中的全球硅循环的优化模型。通过有条件地将透光带中的硅酸恢复到观测浓度来模拟生物吸收，其中模拟浓度超过观测气候学。制定了等效线性模型，应用基于格林函数的传输诊断。我们发现模型在 133 m 深度的蛋白石输出量为 16624 Tmol Si/年，其中南大洋 (SO) 提供了该输出量的大约 70%，其中大约 50% 在 2000 m 深度以上溶解。蛋白石溶解速率的全球尺度梯度主要是经向的，而磷酸盐再矿化的全球尺度梯度主要是垂直的。 SO 中与温度相关的硅酸再生的平均深度达到 2300 m，而磷酸盐再矿化的平均深度为 600 m。硅酸从透光区中剥离的效率远高于磷酸盐，仅占全球硅酸库存的 (345)%，而磷酸盐的 (617)% 则被提取。亚南极和热带水域提供了大部分海洋再生硅酸，而南极水域提供了大部分预制硅酸。全球大约一半的硅酸库存被困在连接连续 SO 使用的运输路径中，最后在 SO 中使用的硅酸只有 (52)% 的机会下次在 SO 之外使用。这种捕集消耗了亚南极模式水中的硅酸（相对于磷酸盐），其有 (44 +/- 2)% 的概率逃脱连续的 SO 使用。要点数据约束模型量化蛋白石输出和硅酸运输路径估计来自关键来源区域的预制和再生成分硅酸平均经历 20$\pm$8 连续南洋利用
We analyze an optimized model of the global silicon cycle embedded in a data-assimilated steady ocean circulation. Biological uptake is modeled by conditionally restoring silicic acid in the euphotic zone to observed concentrations where the modeled concentrations exceed the observational climatology. An equivalent linear model is formulated to which Green-function-based transport diagnostics are applied. We find that the models' opal export through 133 m depth is 16624 Tmol Si/yr, with the Southern Ocean (SO) providing approximate to 70% of this export, approximate to 50% of which dissolves above 2000 m depth. The global-scale gradients of the opal dissolution rate are primarily meridional, while the global-scale gradients of phosphate remineralization are primarily vertical. The mean depth of the temperature-dependent silicic-acid regeneration reaches 2300 m in the SO, compared to 600 m for phosphate remineralization. Silicic acid is stripped out of the euphotic zone far more efficiently than phosphate, with only (345)% of the global silicic-acid inventory being preformed, compared to (617)% for phosphate. Subantarctic and tropical waters contribute most of the ocean's regenerated silicic acid, while Antarctic waters provide most of the preformed silicic acid. About half of the global silicic-acid inventory is trapped in transport paths connecting successive SO utilizations, with silicic acid last utilized in the SO having only a (52)% chance of being next utilized outside the SO. This trapping depletes subantarctic mode waters of silicic acid relative to phosphate, which has a (44 +/- 2)% probability of escaping successive SO utilization.Key PointsA data-constrained model quantifies opal export and silicic acid transport paths Preformed and regenerated components from key source regions are estimated Silicic acid undergoes 20$\pm$8 successive S.-Ocean utilization on average