Radioisotope constraints of Arctic deep water export to the North Atlantic

• Published in: Nature Communications
• Main Authors: Kipp, Lauren E., McManus, Jerry F., Kienast, Markus
• Other Authors: Canada First Research Excellence Fund Lamont-Doherty Earth Observatory Climate Center, National Science Foundation
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Science and Business Media LLC 2021
• Subjects: General Physics and Astronomy; General Biochemistry, Genetics and Molecular Biology; General Chemistry; Arctic; Arctic Ocean; Central Basin; Fram Strait; Nordic Seas; North Atlantic Deep Water; North Atlantic
• Online Access: http://dx.doi.org/10.1038/s41467-021-23877-4; http://www.nature.com/articles/s41467-021-23877-4.pdf; http://www.nature.com/articles/s41467-021-23877-4

Abstract The export of deep water from the Arctic to the Atlantic contributes to the formation of North Atlantic Deep Water, a crucial component of global ocean circulation. Records of protactinium-231 ( 231 Pa) and thorium-230 ( 230 Th) in Arctic sediments can provide a measure of this export, but well-constrained sedimentary budgets of these isotopes have been difficult to achieve in the Arctic Ocean. Previous studies revealed a deficit of 231 Pa in central Arctic sediments, implying that some 231 Pa is either transported to the margins, where it may be removed in areas of higher particle flux, or exported from the Arctic via deep water advection. Here we investigate this “missing sink” of Arctic 231 Pa and find moderately increased 231 Pa deposition along Arctic margins. Nonetheless, we determine that most 231 Pa missing from the central basin must be lost via advection into the Nordic Seas, requiring deep water advection of 1.1 – 6.4 Sv through Fram Strait.