Increased deep ocean carbon storage is often invoked as the major sink for lower atmospheric CO₂ concentrations during past ice ages. In order to improve the understanding of the changes in ocean dynamics facilitating such increased oceanic carbon storage, we assess the variability of deep water provenance in the Atlantic by reconstructing authigenic Nd isotopes from North Atlantic site U1313 over the past ∼100 kyr. Under consideration of these new constraints for the northern Nd isotope end-member, we find only limited long-term variations in the meridional and intra-basin water-mass gradients suggesting a prevalence of northern-sourced water (NSW) throughout the past 100 kyr. Tentative results suggest that during the glacial period of Marine Isotope Stage 4 NSW proportions even increased by additional ∼15% in the equatorial and Northeast Atlantic, calling into question the notion that cold climates promote the expansion of southern-sourced water.

中文翻译：

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冰川-间冰期时间尺度上稳定的大西洋深水质量来源

增加的深海碳储存量通常被称为大气中较低 CO ₂的主要汇过去冰河时期的浓度。为了提高对促进海洋碳储存增加的海洋动力学变化的理解，我们通过重建北大西洋站点 U1313 过去~100 kyr 的自生 Nd 同位素来评估大西洋深水来源的变异性。考虑到对北部 Nd 同位素端元的这些新限制，我们发现经向和盆地内水质量梯度的长期变化有限，表明在过去 100 kyr 中普遍存在北部源水 (NSW) . 初步结果表明，在海洋同位素第 4 阶段新南威尔士州的冰川期，赤道和东北大西洋的比例甚至增加了约 15%，