4.4 Article

Little Change in Ice Age Water Mass Structure From Cape Basin Benthic Neodymium and Carbon Isotopes

期刊

出版社

AMER GEOPHYSICAL UNION
DOI: 10.1029/2021PA004281

关键词

Ocean circulation; Neodymium isotopes; Carbon isotopes

资金

  1. NSF [OCE-1831415]

向作者/读者索取更多资源

The study found that the circulation structure in the far South Atlantic underwent changes throughout the last glacial cycle, contradicting the common conception of the upper circulation cell in the Atlantic being shoaled at the Last Glacial Maximum. Despite little change in mid-depth ocean structure, greater stratification between mid-depth and abyssal sites developed, which may have contributed to glacial carbon storage in the deep ocean.
A common conception of the deep ocean during ice age episodes is that the upper circulation cell in the Atlantic was shoaled at the Last Glacial Maximum compared to today, and that this configuration facilitated enhanced carbon storage in the deep ocean, contributing to glacial CO2 draw-down. Here, we test this notion in the far South Atlantic, investigating changes in glacial circulation structure using paired neodymium and benthic carbon isotope measurements from International Ocean Discovery Program Site U1479, at 2,615 m water depth in the Cape Basin. We infer changes in circulation structure across the last glacial cycle by aligning our site with other existing carbon and neodymium isotope records from the Cape Basin, examining vertical isotope gradients, while determining the relative timing of inferred circulation changes at different depths. We find that Site U1479 had the most negative neodymium isotopic composition across the last glacial cycle among the analyzed sites, indicating that this depth was most strongly influenced by North Atlantic Deep Water (NADW) in both interglacial and glacial intervals. This observation precludes a hypothesized dramatic shoaling of NADW above similar to 2,000 m. Our evidence, however, indicates greater stratification between mid-depth and abyssal sites throughout the last glacial cycle, conditions that developed in Marine Isotope Stage 5. These conditions still may have contributed to glacial carbon storage in the deep ocean, despite little change in the mid-depth ocean structure.

作者

我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。

评论

主要评分

4.4
评分不足

次要评分

新颖性
-
重要性
-
科学严谨性
-
评价这篇论文

推荐

暂无数据
暂无数据