Radium isotopes across the Arctic Ocean show time scales of water mass ventilation and increasing shelf inputs
© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Oceans 123 (2018): 4853-4873, doi:10.1029/2018JC013888. The first full transarctic section of 228Ra in surface wate...
Published in: | Journal of Geophysical Research: Oceans |
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Format: | Article in Journal/Newspaper |
Language: | English |
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2018
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Online Access: | https://hdl.handle.net/1912/10556 |
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/10556 2023-05-15T13:22:45+02:00 Radium isotopes across the Arctic Ocean show time scales of water mass ventilation and increasing shelf inputs Rutgers van der Loeff, Michiel M. Kipp, Lauren Charette, Matthew A. Moore, Willard S. Black, Erin E. Stimac, Ingrid Charkin, Alexander Bauch, Dorothea Valk, Ole Karcher, Michael Krumpen, Thomas Casacuberta, Nuria Smethie, William M. Rember, Robert 2018-07-13 https://hdl.handle.net/1912/10556 en_US eng John Wiley & Sons https://doi.org/10.1029/2018JC013888 Journal of Geophysical Research: Oceans 123 (2018): 4853-4873 https://hdl.handle.net/1912/10556 doi:10.1029/2018JC013888 Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ CC-BY-NC-ND Journal of Geophysical Research: Oceans 123 (2018): 4853-4873 doi:10.1029/2018JC013888 Radium‐228 Thorium‐228 Arctic Ocean Transpolar drift GEOTRACES Article 2018 ftwhoas https://doi.org/10.1029/2018JC013888 2022-05-28T23:00:28Z © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Oceans 123 (2018): 4853-4873, doi:10.1029/2018JC013888. The first full transarctic section of 228Ra in surface waters measured during GEOTRACES cruises PS94 and HLY1502 (2015) shows a consistent distribution with maximum activities in the transpolar drift. Activities in the central Arctic have increased from 2007 through 2011 to 2015. The increased 228Ra input is attributed to stronger wave action on shelves resulting from a longer ice‐free season. A concomitant decrease in the 228Th/228Ra ratio likely results from more rapid transit of surface waters depleted in 228Th by scavenging over the shelf. The 228Ra activities observed in intermediate waters (<1,500 m) in the Amundsen Basin are explained by ventilation with shelf water on a time scale of about 15–18 years, in good agreement with estimates based on SF6 and 129I/236U. The 228Th excess below the mixed layer up to 1,500 m depth can complement 234Th and 210Po as tracers of export production, after correction for the inherent excess resulting from the similarity of 228Ra and 228Th decay times. We show with a Th/Ra profile model that the 228Th/228Ra ratio below 1,500 m is inappropriate for this purpose because it is a delicate balance between horizontal supply of 228Ra and vertical flux of particulate 228Th. The accumulation of 226Ra in the deep Makarov Basin is not associated with an accumulation of Ba and can therefore be attributed to supply from decay of 230Th in the bottom sediment. We estimate a ventilation time of 480 years for the deep Makarov‐Canada Basin, in good agreement with previous estimates using other tracers. U.S. National Science Foundation Grant Numbers: OCE‐1458305, OCE‐1458424; US NSF Grant Number: OCE‐1433922 Article in Journal/Newspaper amundsen basin Arctic Arctic Ocean canada basin Central Arctic makarov basin Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Amundsen Basin ENVELOPE(74.000,74.000,87.000,87.000) Arctic Arctic Ocean Canada Makarov Basin ENVELOPE(170.000,170.000,87.000,87.000) Journal of Geophysical Research: Oceans 123 7 4853 4873 |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
English |
topic |
Radium‐228 Thorium‐228 Arctic Ocean Transpolar drift GEOTRACES |
spellingShingle |
Radium‐228 Thorium‐228 Arctic Ocean Transpolar drift GEOTRACES Rutgers van der Loeff, Michiel M. Kipp, Lauren Charette, Matthew A. Moore, Willard S. Black, Erin E. Stimac, Ingrid Charkin, Alexander Bauch, Dorothea Valk, Ole Karcher, Michael Krumpen, Thomas Casacuberta, Nuria Smethie, William M. Rember, Robert Radium isotopes across the Arctic Ocean show time scales of water mass ventilation and increasing shelf inputs |
topic_facet |
Radium‐228 Thorium‐228 Arctic Ocean Transpolar drift GEOTRACES |
description |
© The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Geophysical Research: Oceans 123 (2018): 4853-4873, doi:10.1029/2018JC013888. The first full transarctic section of 228Ra in surface waters measured during GEOTRACES cruises PS94 and HLY1502 (2015) shows a consistent distribution with maximum activities in the transpolar drift. Activities in the central Arctic have increased from 2007 through 2011 to 2015. The increased 228Ra input is attributed to stronger wave action on shelves resulting from a longer ice‐free season. A concomitant decrease in the 228Th/228Ra ratio likely results from more rapid transit of surface waters depleted in 228Th by scavenging over the shelf. The 228Ra activities observed in intermediate waters (<1,500 m) in the Amundsen Basin are explained by ventilation with shelf water on a time scale of about 15–18 years, in good agreement with estimates based on SF6 and 129I/236U. The 228Th excess below the mixed layer up to 1,500 m depth can complement 234Th and 210Po as tracers of export production, after correction for the inherent excess resulting from the similarity of 228Ra and 228Th decay times. We show with a Th/Ra profile model that the 228Th/228Ra ratio below 1,500 m is inappropriate for this purpose because it is a delicate balance between horizontal supply of 228Ra and vertical flux of particulate 228Th. The accumulation of 226Ra in the deep Makarov Basin is not associated with an accumulation of Ba and can therefore be attributed to supply from decay of 230Th in the bottom sediment. We estimate a ventilation time of 480 years for the deep Makarov‐Canada Basin, in good agreement with previous estimates using other tracers. U.S. National Science Foundation Grant Numbers: OCE‐1458305, OCE‐1458424; US NSF Grant Number: OCE‐1433922 |
format |
Article in Journal/Newspaper |
author |
Rutgers van der Loeff, Michiel M. Kipp, Lauren Charette, Matthew A. Moore, Willard S. Black, Erin E. Stimac, Ingrid Charkin, Alexander Bauch, Dorothea Valk, Ole Karcher, Michael Krumpen, Thomas Casacuberta, Nuria Smethie, William M. Rember, Robert |
author_facet |
Rutgers van der Loeff, Michiel M. Kipp, Lauren Charette, Matthew A. Moore, Willard S. Black, Erin E. Stimac, Ingrid Charkin, Alexander Bauch, Dorothea Valk, Ole Karcher, Michael Krumpen, Thomas Casacuberta, Nuria Smethie, William M. Rember, Robert |
author_sort |
Rutgers van der Loeff, Michiel M. |
title |
Radium isotopes across the Arctic Ocean show time scales of water mass ventilation and increasing shelf inputs |
title_short |
Radium isotopes across the Arctic Ocean show time scales of water mass ventilation and increasing shelf inputs |
title_full |
Radium isotopes across the Arctic Ocean show time scales of water mass ventilation and increasing shelf inputs |
title_fullStr |
Radium isotopes across the Arctic Ocean show time scales of water mass ventilation and increasing shelf inputs |
title_full_unstemmed |
Radium isotopes across the Arctic Ocean show time scales of water mass ventilation and increasing shelf inputs |
title_sort |
radium isotopes across the arctic ocean show time scales of water mass ventilation and increasing shelf inputs |
publisher |
John Wiley & Sons |
publishDate |
2018 |
url |
https://hdl.handle.net/1912/10556 |
long_lat |
ENVELOPE(74.000,74.000,87.000,87.000) ENVELOPE(170.000,170.000,87.000,87.000) |
geographic |
Amundsen Basin Arctic Arctic Ocean Canada Makarov Basin |
geographic_facet |
Amundsen Basin Arctic Arctic Ocean Canada Makarov Basin |
genre |
amundsen basin Arctic Arctic Ocean canada basin Central Arctic makarov basin |
genre_facet |
amundsen basin Arctic Arctic Ocean canada basin Central Arctic makarov basin |
op_source |
Journal of Geophysical Research: Oceans 123 (2018): 4853-4873 doi:10.1029/2018JC013888 |
op_relation |
https://doi.org/10.1029/2018JC013888 Journal of Geophysical Research: Oceans 123 (2018): 4853-4873 https://hdl.handle.net/1912/10556 doi:10.1029/2018JC013888 |
op_rights |
Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_rightsnorm |
CC-BY-NC-ND |
op_doi |
https://doi.org/10.1029/2018JC013888 |
container_title |
Journal of Geophysical Research: Oceans |
container_volume |
123 |
container_issue |
7 |
container_start_page |
4853 |
op_container_end_page |
4873 |
_version_ |
1766366769666064384 |