In this study, we report our ocean general circulation model simulations of the global distribution of rare earth elements (REEs) in the ocean. As previously reported (Oka et al. in Glob Biogeochem Cycles 23:1–16, 2009), the vertical profiles of REEs in the North Pacific Ocean are strongly controlled by the reversible scavenging process, and the systematic differences between REEs can be reproduced in the model by selecting an appropriate model parameter which controls affinity to particles. We here demonstrate that the external REE input from the coastal regions also plays a role in controlling the vertical profiles of dissolved REE and their inter-basin differences. The role of the external inputs is especially important for light REEs, such as neodymium (Nd). The linear increase in Nd concentration in the North Pacific Ocean cannot be sufficiently reproduced by the reversible scavenging alone; rather, a combination of the reversible scavenging and the external inputs is necessary. On the other hand, the distribution of heavy REEs, such as lutetium (Lu), can be broadly reproduced without the external inputs, suggesting that Lu has similarity with conservative nutrient-like tracer. When compared with REE observations compiled from both the recently obtained GEOTRACES dataset and pre-GEOTRACES reported data, our simulations successfully reproduced the overall features of these observations. Observational data suggested that the vertical profiles of REEs are not the same among the basins; our model simulations demonstrate that this feature can be clearly reproduced by considering both the reversible scavenging and the external REE inputs from the coastal regions.

在这项研究中，我们报告了海洋中海洋稀土元素（REE）全球分布的海洋一般环流模型模拟。如先前的报道（Oka等人，在Glob Biogeochem Cycles 23：1–16，2009中），北太平洋REE的垂直剖面受到可逆清除过程的强烈控制，并且REE之间的系统差异可以在通过选择适当的模型参数来控制模型对模型的亲和力。我们在这里表明，来自沿海地区的外部REE输入在控制溶解REE的垂直剖面及其盆地间差异方面也起着作用。外部输入的作用对于轻稀土元素（例如钕（Nd））尤其重要。单靠可逆清除不能充分再现北太平洋Nd浓度的线性增加。相反，必须将可逆清除和外部输入结合起来。另一方面，重稀土元素的分布，例如（Lu），可以在没有外部输入的情况下广泛地复制，这表明Lu与保守的类似营养物的示踪剂具有相似性。当与从最近获得的GEOTRACES数据集和pre-GEOTRACES报告的数据中汇编的REE观测值进行比较时，我们的模拟成功地再现了这些观测值的整体特征。观测数据表明，各盆地之间的稀土元素垂直剖面不相同；