EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Tracing Ocean circulation at the AR7W and OVIDE lines using artificial radionuclides 

Lisa Gerlinde Thekla Leist1, Maxi Castrillejo2, John N. Smith3, Marcus Christl4, and Núria Casacuberta1,4
Lisa Gerlinde Thekla Leist et al.
  • 1ETH Zurich, Institute for Biogeochemistry and Pollutant Dynamics, D-USYS, Zurich, Switzerland (
  • 2Department of Physics, Imperial College London, London, United Kingdom
  • 3Bedford Institute of Oceanography, Fisheries and Oceans Canada, Dartmouth, NS, Canada
  • 4Laboratory of Ion Beam Physics, ETH Zürich, Switzerland

The Subpolar North Atlantic (SPNA) and Labrador Sea are key regions for deep and intermediate water mass formation and contribute to the southward return flow of the lower limb of the Atlantic Meridional Overturning Circulation (AMOC).

The origin and circulation pathways of these water masses can now be studied using the artificial radionuclides 129I and 236U. These tracers are mainly released to the Nordic seas by the European nuclear reprocessing plants of La Hague and Sellafield since the 1960s. This point like source provides a unique fingerprint for Atlantic waters entering the Arctic Ocean and recirculation to the western SPNA.

Here we will present results of the distribution of 129I and 236U in the Labrador Sea (AR7W Line) and the SPNA (OVIDE Line). The 129I concentrations and its temporal evolution is studied at 11 stations on a time series that started in 2014. In addition, first results of 236U  will also be  presented along the AR7W line.

At the timeseries the 129I concentration shows a general increase with time and from east to west, reaching its highest concentration in the deep overflow waters and along the Eastern and Western Greenland current.

The combination of the well-known tracer 129I with 236U allows to study the origin and mixing of different water masses in the SPNA.

How to cite: Leist, L. G. T., Castrillejo, M., Smith, J. N., Christl, M., and Casacuberta, N.: Tracing Ocean circulation at the AR7W and OVIDE lines using artificial radionuclides , EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-11459,, 2023.

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