129I and 236U distribution in the subpolar North Atlantic unravels water mass provenance in AR7W and A25 lines
The subpolar North Atlantic (SPNA) is crucial in the global ocean circulation system and one of the few regions where deep convection occurs. The intermediate and deep waters formed in the SPNA have long been investigated, yet their sources and pathways are not fully understood. In this study, we em...
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Frontiers Media S.A.
2024-12-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2024.1470675/full |
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| author | Lisa G. T. Leist Maxi Castrillejo John Norton Smith Marcus Christl Christof Vockenhuber Antón Velo Pascale Lherminier Núria Casacuberta Núria Casacuberta |
| author_facet | Lisa G. T. Leist Maxi Castrillejo John Norton Smith Marcus Christl Christof Vockenhuber Antón Velo Pascale Lherminier Núria Casacuberta Núria Casacuberta |
| author_sort | Lisa G. T. Leist |
| collection | DOAJ |
| description | The subpolar North Atlantic (SPNA) is crucial in the global ocean circulation system and one of the few regions where deep convection occurs. The intermediate and deep waters formed in the SPNA have long been investigated, yet their sources and pathways are not fully understood. In this study, we employ a combination of two radionuclide tracers, namely, 129I and 236U, to understand water mass provenance and mixing in the SPNA. The concentrations measured between Portugal and Greenland and across the Labrador Sea in 2020/2021 agreed with previously observed tracer distributions. The highest tracer concentrations were measured in the East Greenland Current (EGC), Denmark Strait Overflow Water (DSOW), and, to a lesser extent, in the eastward-flowing Labrador Sea Water (LSW). In contrast, waters of southern origin such as the North East Antarctic Bottom Water and North East Atlantic Central Water (ENACW) carried comparably smaller amounts of 129I. By using a binary mixing model, we estimated that the EGC contains about 29%–32% of the Polar Surface Water outflowing the Fram Strait. DSOW was mainly derived from 20% to 35% Return Atlantic Water and mixed with LSW. The Iceland Scotland Overflow Water (ISOW) evolved into North East Atlantic Deep Water in the Irminger and Labrador seas primarily by mixing with LSW and, to a lesser extent, with DSOW. The 129I and 236U binary mixing approach was less conclusive for LSW, reaching the current limitation of the model. This study suggests potential benefits and limitations of using 129I and 236U to investigate the mixing and provenance of water masses in the SPNA. |
| format | Article |
| id | doaj-art-dce6d3bd10c049bbbc4e2ca5f0c6883c |
| institution | DOAJ |
| issn | 2296-7745 |
| language | English |
| publishDate | 2024-12-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj-art-dce6d3bd10c049bbbc4e2ca5f0c6883c2025-08-20T02:49:01ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452024-12-011110.3389/fmars.2024.14706751470675129I and 236U distribution in the subpolar North Atlantic unravels water mass provenance in AR7W and A25 linesLisa G. T. Leist0Maxi Castrillejo1John Norton Smith2Marcus Christl3Christof Vockenhuber4Antón Velo5Pascale Lherminier6Núria Casacuberta7Núria Casacuberta8Department of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, Eidgenössische Technische Hochschule (ETH) Zürich, Zurich, SwitzerlandInstitute of Earth Sciences, University of Lausanne, Lausanne, SwitzerlandBedford Institute of Oceanography, Fisheries and Oceans Canada, Dartmouth, NS, CanadaLaboratory of Ion Beam Physics, Department of Physics, ETH Zurich, Zurich, SwitzerlandLaboratory of Ion Beam Physics, Department of Physics, ETH Zurich, Zurich, SwitzerlandInstituto de Investigacións Mariñas, IIM-CSIC, Vigo, SpainLaboratoire d’Océanographie Physique et Spatiale (LOPS), University of Brest, CNRS, Ifremer, IRD, IUEM, Plouzané, FranceDepartment of Environmental Systems Science, Institute of Biogeochemistry and Pollutant Dynamics, Eidgenössische Technische Hochschule (ETH) Zürich, Zurich, SwitzerlandLaboratory of Ion Beam Physics, Department of Physics, ETH Zurich, Zurich, SwitzerlandThe subpolar North Atlantic (SPNA) is crucial in the global ocean circulation system and one of the few regions where deep convection occurs. The intermediate and deep waters formed in the SPNA have long been investigated, yet their sources and pathways are not fully understood. In this study, we employ a combination of two radionuclide tracers, namely, 129I and 236U, to understand water mass provenance and mixing in the SPNA. The concentrations measured between Portugal and Greenland and across the Labrador Sea in 2020/2021 agreed with previously observed tracer distributions. The highest tracer concentrations were measured in the East Greenland Current (EGC), Denmark Strait Overflow Water (DSOW), and, to a lesser extent, in the eastward-flowing Labrador Sea Water (LSW). In contrast, waters of southern origin such as the North East Antarctic Bottom Water and North East Atlantic Central Water (ENACW) carried comparably smaller amounts of 129I. By using a binary mixing model, we estimated that the EGC contains about 29%–32% of the Polar Surface Water outflowing the Fram Strait. DSOW was mainly derived from 20% to 35% Return Atlantic Water and mixed with LSW. The Iceland Scotland Overflow Water (ISOW) evolved into North East Atlantic Deep Water in the Irminger and Labrador seas primarily by mixing with LSW and, to a lesser extent, with DSOW. The 129I and 236U binary mixing approach was less conclusive for LSW, reaching the current limitation of the model. This study suggests potential benefits and limitations of using 129I and 236U to investigate the mixing and provenance of water masses in the SPNA.https://www.frontiersin.org/articles/10.3389/fmars.2024.1470675/fullradionuclidesI-129U-236tracerswater masses provenancesubpolar North Atlantic |
| spellingShingle | Lisa G. T. Leist Maxi Castrillejo John Norton Smith Marcus Christl Christof Vockenhuber Antón Velo Pascale Lherminier Núria Casacuberta Núria Casacuberta 129I and 236U distribution in the subpolar North Atlantic unravels water mass provenance in AR7W and A25 lines Frontiers in Marine Science radionuclides I-129 U-236 tracers water masses provenance subpolar North Atlantic |
| title | 129I and 236U distribution in the subpolar North Atlantic unravels water mass provenance in AR7W and A25 lines |
| title_full | 129I and 236U distribution in the subpolar North Atlantic unravels water mass provenance in AR7W and A25 lines |
| title_fullStr | 129I and 236U distribution in the subpolar North Atlantic unravels water mass provenance in AR7W and A25 lines |
| title_full_unstemmed | 129I and 236U distribution in the subpolar North Atlantic unravels water mass provenance in AR7W and A25 lines |
| title_short | 129I and 236U distribution in the subpolar North Atlantic unravels water mass provenance in AR7W and A25 lines |
| title_sort | 129i and 236u distribution in the subpolar north atlantic unravels water mass provenance in ar7w and a25 lines |
| topic | radionuclides I-129 U-236 tracers water masses provenance subpolar North Atlantic |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2024.1470675/full |
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