Intensity of Th and Pa scavenging partitioned by particle chemistry in the North Atlantic Ocean
The natural radionuclides 231Pa and 230Th are incorporated into the marine sediment record by scavenging, or adsorption to various particle types, via chemical reactions that are not fully understood. Because these isotopes have potential value in tracing several oceanographic processes, we investig...
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ftunivrhodeislan:oai:digitalcommons.uri.edu:gsofacpubs-1629 2023-07-30T04:05:28+02:00 Intensity of Th and Pa scavenging partitioned by particle chemistry in the North Atlantic Ocean Hayes, Christopher T. Anderson, Robert F. Fleischer, Martin Q. Vivancos, Sebastian M. Lam, Phoebe J. Ohnemus, Daniel C. Huang, Kuo-Fang Robinson, Laura F. Lu, Yanbin Cheng, Hai Edwards, R. Lawrence Moran, S. Bradley 2015-01-01T08:00:00Z application/pdf https://digitalcommons.uri.edu/gsofacpubs/655 https://doi.org/10.1016/j.marchem.2015.01.006 https://digitalcommons.uri.edu/context/gsofacpubs/article/1629/viewcontent/Moran_IntensityofTh_2015.pdf unknown DigitalCommons@URI https://digitalcommons.uri.edu/gsofacpubs/655 doi:10.1016/j.marchem.2015.01.006 https://digitalcommons.uri.edu/context/gsofacpubs/article/1629/viewcontent/Moran_IntensityofTh_2015.pdf http://creativecommons.org/licenses/by-nc-nd/4.0/ Graduate School of Oceanography Faculty Publications text 2015 ftunivrhodeislan https://doi.org/10.1016/j.marchem.2015.01.006 2023-07-17T18:58:21Z The natural radionuclides 231Pa and 230Th are incorporated into the marine sediment record by scavenging, or adsorption to various particle types, via chemical reactions that are not fully understood. Because these isotopes have potential value in tracing several oceanographic processes, we investigate the nature of scavenging using trans-Atlantic measurements of dissolved (< 0.45 μm) and particulate (0.8–51 μm) 231Pa and 230Th, together with major particle composition. We find widespread impact of intense scavenging by authigenic Fe/Mn (hydr)oxides, in the form of hydrothermal particles emanating from the Mid-Atlantic ridge and particles resuspended from reducing conditions near the seafloor off the coast of West Africa. Biogenic opal was not found to be a significant scavenging phase for either element in this sample set, essentially because of its low abundance and small dynamic range at the studied sites. Distribution coefficients in shallow (< 200 m) depths are anomalously low which suggests either the unexpected result of a low scavenging intensity for organic matter or that, in water masses containing abundant organic-rich particles, a greater percentage of radionuclides exist in the colloidal or complexed phase. In addition to particle concentration, the oceanic distribution of particle types likely plays a significant role in the ultimate distribution of sedimentary 230Th and 231Pa. Text North Atlantic University of Rhode Island: DigitalCommons@URI Mid-Atlantic Ridge Marine Chemistry 170 49 60 |
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University of Rhode Island: DigitalCommons@URI |
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ftunivrhodeislan |
language |
unknown |
description |
The natural radionuclides 231Pa and 230Th are incorporated into the marine sediment record by scavenging, or adsorption to various particle types, via chemical reactions that are not fully understood. Because these isotopes have potential value in tracing several oceanographic processes, we investigate the nature of scavenging using trans-Atlantic measurements of dissolved (< 0.45 μm) and particulate (0.8–51 μm) 231Pa and 230Th, together with major particle composition. We find widespread impact of intense scavenging by authigenic Fe/Mn (hydr)oxides, in the form of hydrothermal particles emanating from the Mid-Atlantic ridge and particles resuspended from reducing conditions near the seafloor off the coast of West Africa. Biogenic opal was not found to be a significant scavenging phase for either element in this sample set, essentially because of its low abundance and small dynamic range at the studied sites. Distribution coefficients in shallow (< 200 m) depths are anomalously low which suggests either the unexpected result of a low scavenging intensity for organic matter or that, in water masses containing abundant organic-rich particles, a greater percentage of radionuclides exist in the colloidal or complexed phase. In addition to particle concentration, the oceanic distribution of particle types likely plays a significant role in the ultimate distribution of sedimentary 230Th and 231Pa. |
format |
Text |
author |
Hayes, Christopher T. Anderson, Robert F. Fleischer, Martin Q. Vivancos, Sebastian M. Lam, Phoebe J. Ohnemus, Daniel C. Huang, Kuo-Fang Robinson, Laura F. Lu, Yanbin Cheng, Hai Edwards, R. Lawrence Moran, S. Bradley |
spellingShingle |
Hayes, Christopher T. Anderson, Robert F. Fleischer, Martin Q. Vivancos, Sebastian M. Lam, Phoebe J. Ohnemus, Daniel C. Huang, Kuo-Fang Robinson, Laura F. Lu, Yanbin Cheng, Hai Edwards, R. Lawrence Moran, S. Bradley Intensity of Th and Pa scavenging partitioned by particle chemistry in the North Atlantic Ocean |
author_facet |
Hayes, Christopher T. Anderson, Robert F. Fleischer, Martin Q. Vivancos, Sebastian M. Lam, Phoebe J. Ohnemus, Daniel C. Huang, Kuo-Fang Robinson, Laura F. Lu, Yanbin Cheng, Hai Edwards, R. Lawrence Moran, S. Bradley |
author_sort |
Hayes, Christopher T. |
title |
Intensity of Th and Pa scavenging partitioned by particle chemistry in the North Atlantic Ocean |
title_short |
Intensity of Th and Pa scavenging partitioned by particle chemistry in the North Atlantic Ocean |
title_full |
Intensity of Th and Pa scavenging partitioned by particle chemistry in the North Atlantic Ocean |
title_fullStr |
Intensity of Th and Pa scavenging partitioned by particle chemistry in the North Atlantic Ocean |
title_full_unstemmed |
Intensity of Th and Pa scavenging partitioned by particle chemistry in the North Atlantic Ocean |
title_sort |
intensity of th and pa scavenging partitioned by particle chemistry in the north atlantic ocean |
publisher |
DigitalCommons@URI |
publishDate |
2015 |
url |
https://digitalcommons.uri.edu/gsofacpubs/655 https://doi.org/10.1016/j.marchem.2015.01.006 https://digitalcommons.uri.edu/context/gsofacpubs/article/1629/viewcontent/Moran_IntensityofTh_2015.pdf |
geographic |
Mid-Atlantic Ridge |
geographic_facet |
Mid-Atlantic Ridge |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
Graduate School of Oceanography Faculty Publications |
op_relation |
https://digitalcommons.uri.edu/gsofacpubs/655 doi:10.1016/j.marchem.2015.01.006 https://digitalcommons.uri.edu/context/gsofacpubs/article/1629/viewcontent/Moran_IntensityofTh_2015.pdf |
op_rights |
http://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_doi |
https://doi.org/10.1016/j.marchem.2015.01.006 |
container_title |
Marine Chemistry |
container_volume |
170 |
container_start_page |
49 |
op_container_end_page |
60 |
_version_ |
1772817397834579968 |