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Tracing the Three Atlantic Branches Entering the Arctic Ocean With 129 I and 236 U
Author(s) -
Casacuberta N.,
Christl M.,
Vockenhuber C.,
Wefing A.M.,
Wacker L.,
Masqué P.,
Synal H.A.,
Rutgers van der Loeff M.
Publication year - 2018
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2018jc014168
Subject(s) - oceanography , arctic , seawater , north atlantic deep water , gulf stream , arctic dipole anomaly , transect , the arctic , geology , thermohaline circulation , arctic ice pack , drift ice
This study presents the data on 129 I and 236 U concentrations in seawater samples and sea ice cores obtained during two expeditions to the Arctic Ocean that took place onboard R/V Polarstern (PS94) and R/V Lance (N‐ICE2015) in summer 2015. Carbon‐14 was also measured in the deep water samples from the Nansen, Amundsen, and Makarov Basins. The main goal was to investigate the distribution of 129 I and 236 U in a transect from the Norwegian Coast to the Makarov Basin to fully exploit the potential of combining 129 I and 236 U as a dual tracer to track Atlantic waters throughout the Arctic Ocean. The use of the 129 I/ 236 U and 236 U/ 238 U atom ratios allowed identifying a third Atlantic branch that enters the Arctic Ocean (the Arctic Shelf Break Branch) following the Norwegian Coastal Current that carries a larger proportion of the European reprocessing plants signal compared to Fram Strait Branch Water and Barents Sea Branch Water. The combination of 129 I and 236 U also allowed quantifying the different proportions of the La Hague stream, the Scottish stream, and Atlantic waters forming the three Atlantic branches of the Arctic Ocean Boundary Current. The results show that the 129 I/ 236 U atom ratio can now be used to identify the different Atlantic branches entering the Arctic Ocean. New input functions for 129 I, 236 U, and 129 I/ 236 U have also been described for each branch, which can be further used for calculation of transit time distributions of Atlantic waters.