High-resolution Cd isotope systematics in multiple zones of the Southern Ocean from the Antarctic Circumnavigation Expedition
High-resolution Cd isotope systematics in multiple zones of the Southern Ocean from the Antarctic Circumnavigation Expedition
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南极环球航行南大洋多个区域的高分辨率镉同位素系统学
DOI：
10.1016/j.epsl.2019.115799
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发表时间：
2019
影响因子：
5.3
通讯作者：
D. Vance
中科院分区：
文献类型：
--
作者：
M. Sieber;T. Conway;G. D. de Souza;C. Hassler;M. Ellwood;D. Vance
摘要南大洋在决定镉等痕量金属的全球分布中起着重要作用。在这里，我们提出了17个高深度分辨率的剖面溶解镉及其稳定同位素组成（δ 114镉）的顶部1000米的太平洋和大西洋部门的南大洋，收集在南极环航考察。我们的数据集加强了这样一种观点，即镉及其同位素在该地区的浅层生物循环占主导地位。仔细检查在南大洋的不同区域的镉循环的变化揭示了如何吸收和再生，季节性混合，和上升流之间的相互作用控制在这一地区的镉和δ 114镉。这些系统学的唯一偏差是由于当地过程的影响，如大陆的影响或铁施肥，靠近默茨冰川和Balleny群岛，分别。冬季深对流将南大洋Cd同位素特征纳入亚南极模态水和南极中层水在水团形成。通过对已发表的数据的分析，我们首次完整地描述了Cd在整个太平洋中的循环，揭示了南大洋控制Cd和δ 114 Cd全球循环的方式;类似于Si或Zn，我们提出南大洋过程，与全球海洋环流相结合，导致分为两个单独的Cd制度，在富含镉的深海环之上的贫镉表层海洋。因此，全球范围内Cd和PO 4之间的关系主要是南大洋这些过程的结果，而不是两种元素之间的局部相关性。
Abstract The Southern Ocean plays a major role in determining the global distribution of trace metals such as cadmium (Cd). Here, we present 17 high-depth-resolution profiles of dissolved Cd and its stable isotope composition (δ 114 Cd) over the top 1000 m of the Pacific and Atlantic sectors of the Southern Ocean, collected during the Antarctic Circumnavigation Expedition. Our dataset reinforces the view that Cd and its isotopes are dominated by shallow biological cycling in this region. A close examination of variations in Cd cycling across the different zones of the Southern Ocean reveals how the interplay between uptake and regeneration, seasonal mixing, and upwelling controls both Cd and δ 114 Cd in this region. The only deviations from these systematics are due to the influence of local processes such as continental influence or Fe-fertilization, close to the Mertz Glacier and the Balleny Islands, respectively. Deep convection during winter incorporates the Southern Ocean Cd isotope signatures into Subantarctic Mode Water and Antarctic Intermediate Water during water mass formation. Incorporating published data, we present the first complete picture of how Cd is cycled through the entire Pacific Ocean, revealing the manner in which the Southern Ocean controls the global cycling of Cd and δ 114 Cd; analogous to Si or Zn, we propose that Southern Ocean processes, in combination with global ocean circulation, cause a division into two separate Cd regimes, a Cd-depleted surface ocean above a Cd-rich deep ocean loop. Therefore, the relationship between Cd and PO 4 on a global scale is largely a result of these processes in the Southern Ocean, rather than a local correlation between the two elements.