On calcium-to-alkalinity anomalies in the North Pacific, Red Sea, Indian Ocean and Southern Ocean
On calcium-to-alkalinity anomalies in the North Pacific, Red Sea, Indian Ocean and Southern Ocean
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DOI：
10.1016/j.gca.2021.03.027
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发表时间：
2021-04
影响因子：
5
通讯作者：
Z. Steiner;A. Sarkar;Xuewu Liu;W. Berelson;J. Adkins;E. Achterberg;P. Sabu;S. Prakash;P. N. Vinaychandran;R. Byrne;A. Turchyn
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文献类型：
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作者：
Z. Steiner;A. Sarkar;Xuewu Liu;W. Berelson;J. Adkins;E. Achterberg;P. Sabu;S. Prakash;P. N. Vinaychandran;R. Byrne;A. Turchyn
预测二氧化碳增加对未来海洋酸化影响的一个重要因素是正确理解控制碳酸钙矿物 (CaCO3) 产生和溶解的相互作用。海洋中 CaCO3 的产生和溶解可以通过测量海水钙浓度和总碱度 (AT) 在大空间尺度上进行评估，但过去的研究表明，北太平洋和印度洋 CaCO3 循环的钙和基于 AT 的平衡之间可能存在很大差异。在这里，我们分析了沿着北太平洋、南大洋、热带印度洋和红海横断面收集的水柱样本的钙、营养物和 AT 浓度。我们发现在热带印度洋水柱顶部 1000 米的 ATanomaly 上空存在过量的钙。这种异常现象的根源是红海地下石膏沉积物的溶解。与之前的研究相比，我们没有发现北太平洋钙超异常的证据。我们的结果表明，在大多数情况下，钙和 ATdata 吻合良好，可用于重建海洋 CaCO3 循环。
An important factor for predicting the effect of increased CO2on future acidification of the ocean is a proper understanding of the interactions controlling production and dissolution of calcium carbonate minerals (CaCO3). The production and dissolution of CaCO3in the ocean can be assessed over large spatial scales by measuring seawater calcium concentrations and total alkalinity (AT), yet past studies suggest that there could be large discrepancies between calcium and AT-based balances of the CaCO3cycle in the North Pacific and Indian Oceans. Here, we analyse water column samples collected along transects in the North Pacific, Southern Ocean, tropical Indian Ocean and Red Sea for their concentrations of calcium, nutrients, and AT. We find that there is an excess calcium over ATanomaly in the top 1000 m of the tropical Indian Ocean water-column. The source of this anomaly is the dissolution of subsurface gypsum deposits in the Red Sea. We find no evidence for calcium-over-ATanomalies in the North Pacific, in contrast to previous studies. Our results show that, in most cases, calcium and ATdata agree well and can be used to reconstruct the marine CaCO3cycle.