Dissolved and Particulate Barium Distributions Along the US GEOTRACES North Atlantic and East Pacific Zonal Transects (GA03 and GP16): Global Implications for the Marine Barium Cycle
Processes controlling dissolved barium (dBa) were investigated along the GEOTRACES GA03 North Atlantic and GP16 Eastern Tropical Pacific transects, which traversed similar physical and biogeochemical provinces. Dissolved Ba concentrations are lowest in surface waters (∼35–50 nmol kg⁻¹) and increase...
Published in: | Global Biogeochemical Cycles |
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Main Authors: | , , , , , , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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American Geophysical Union
2022
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Subjects: | |
Online Access: | https://authors.library.caltech.edu/114949/ https://authors.library.caltech.edu/114949/4/Global%20Biogeochemical%20Cycles%20-%202022%20-%20Rahman%20-%20Dissolved%20and%20Particulate%20Barium%20Distributions%20Along%20the%20US%20GEOTRACES%20North.pdf https://authors.library.caltech.edu/114949/1/2022gb007330-sup-0001-supporting%20information%20si-s01.docx https://authors.library.caltech.edu/114949/2/2022gb007330-sup-0002-table%20si-s01.xlsx https://resolver.caltech.edu/CaltechAUTHORS:20220526-391435000 |
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Caltech Authors (California Institute of Technology) |
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English |
description |
Processes controlling dissolved barium (dBa) were investigated along the GEOTRACES GA03 North Atlantic and GP16 Eastern Tropical Pacific transects, which traversed similar physical and biogeochemical provinces. Dissolved Ba concentrations are lowest in surface waters (∼35–50 nmol kg⁻¹) and increase to 70–80 and 140–150 nmol kg⁻¹ in deep waters of the Atlantic and Pacific transects, respectively. Using water mass mixing models, we estimate conservative mixing that accounts for most of dBa variability in both transects. To examine nonconservative processes, particulate excess Ba (pBa_(xs)) formation and dissolution rates were tracked by normalizing particulate excess ²³⁰Th activities. Th-normalized pBa_(xs) fluxes, with barite as the likely phase, have subsurface maxima in the top 1,000 m (∼100–200 μmol m⁻² year⁻¹ average) in both basins. Barite precipitation depletes dBa within oxygen minimum zones from concentrations predicted by water mass mixing, whereas inputs from continental margins, particle dissolution in the water column, and benthic diffusive flux raise dBa above predications. Average pBa_(xs) burial efficiencies along GA03 and GP16 are ∼37% and 17%–100%, respectively, and do not seem to be predicated on barite saturation indices in the overlying water column. Using published values, we reevaluate the global freshwater dBa river input as 6.6 ± 3.9 Gmol year⁻¹. Estuarine mixing processes may add another 3–13 Gmol year⁻¹. Dissolved Ba inputs from broad shallow continental margins, previously unaccounted for in global marine summaries, are substantial (∼17 Gmol year⁻¹), exceeding terrestrial freshwater inputs. Revising river and shelf dBa inputs may help bring the marine Ba isotope budget more into balance. |
format |
Article in Journal/Newspaper |
author |
Rahman, Shaily Shiller, Alan M. Anderson, Robert F. Charette, Matthew A. Hayes, Christopher T. Gilbert, Melissa Grissom, Karen R. Lam, Phoebe J. Ohnemus, Daniel C. Pavia, Frank J. Twining, Benjamin S. Vivancos, Sebastián M. |
spellingShingle |
Rahman, Shaily Shiller, Alan M. Anderson, Robert F. Charette, Matthew A. Hayes, Christopher T. Gilbert, Melissa Grissom, Karen R. Lam, Phoebe J. Ohnemus, Daniel C. Pavia, Frank J. Twining, Benjamin S. Vivancos, Sebastián M. Dissolved and Particulate Barium Distributions Along the US GEOTRACES North Atlantic and East Pacific Zonal Transects (GA03 and GP16): Global Implications for the Marine Barium Cycle |
author_facet |
Rahman, Shaily Shiller, Alan M. Anderson, Robert F. Charette, Matthew A. Hayes, Christopher T. Gilbert, Melissa Grissom, Karen R. Lam, Phoebe J. Ohnemus, Daniel C. Pavia, Frank J. Twining, Benjamin S. Vivancos, Sebastián M. |
author_sort |
Rahman, Shaily |
title |
Dissolved and Particulate Barium Distributions Along the US GEOTRACES North Atlantic and East Pacific Zonal Transects (GA03 and GP16): Global Implications for the Marine Barium Cycle |
title_short |
Dissolved and Particulate Barium Distributions Along the US GEOTRACES North Atlantic and East Pacific Zonal Transects (GA03 and GP16): Global Implications for the Marine Barium Cycle |
title_full |
Dissolved and Particulate Barium Distributions Along the US GEOTRACES North Atlantic and East Pacific Zonal Transects (GA03 and GP16): Global Implications for the Marine Barium Cycle |
title_fullStr |
Dissolved and Particulate Barium Distributions Along the US GEOTRACES North Atlantic and East Pacific Zonal Transects (GA03 and GP16): Global Implications for the Marine Barium Cycle |
title_full_unstemmed |
Dissolved and Particulate Barium Distributions Along the US GEOTRACES North Atlantic and East Pacific Zonal Transects (GA03 and GP16): Global Implications for the Marine Barium Cycle |
title_sort |
dissolved and particulate barium distributions along the us geotraces north atlantic and east pacific zonal transects (ga03 and gp16): global implications for the marine barium cycle |
publisher |
American Geophysical Union |
publishDate |
2022 |
url |
https://authors.library.caltech.edu/114949/ https://authors.library.caltech.edu/114949/4/Global%20Biogeochemical%20Cycles%20-%202022%20-%20Rahman%20-%20Dissolved%20and%20Particulate%20Barium%20Distributions%20Along%20the%20US%20GEOTRACES%20North.pdf https://authors.library.caltech.edu/114949/1/2022gb007330-sup-0001-supporting%20information%20si-s01.docx https://authors.library.caltech.edu/114949/2/2022gb007330-sup-0002-table%20si-s01.xlsx https://resolver.caltech.edu/CaltechAUTHORS:20220526-391435000 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://authors.library.caltech.edu/114949/4/Global%20Biogeochemical%20Cycles%20-%202022%20-%20Rahman%20-%20Dissolved%20and%20Particulate%20Barium%20Distributions%20Along%20the%20US%20GEOTRACES%20North.pdf https://authors.library.caltech.edu/114949/1/2022gb007330-sup-0001-supporting%20information%20si-s01.docx https://authors.library.caltech.edu/114949/2/2022gb007330-sup-0002-table%20si-s01.xlsx Rahman, Shaily and Shiller, Alan M. and Anderson, Robert F. and Charette, Matthew A. and Hayes, Christopher T. and Gilbert, Melissa and Grissom, Karen R. and Lam, Phoebe J. and Ohnemus, Daniel C. and Pavia, Frank J. and Twining, Benjamin S. and Vivancos, Sebastián M. (2022) Dissolved and Particulate Barium Distributions Along the US GEOTRACES North Atlantic and East Pacific Zonal Transects (GA03 and GP16): Global Implications for the Marine Barium Cycle. Global Biogeochemical Cycles, 36 (6). Art. No. e2022GB007330. ISSN 0886-6236. doi:10.1029/2022gb007330. https://resolver.caltech.edu/CaltechAUTHORS:20220526-391435000 <https://resolver.caltech.edu/CaltechAUTHORS:20220526-391435000> |
op_rights |
cc_by |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1029/2022gb007330 |
container_title |
Global Biogeochemical Cycles |
container_volume |
36 |
container_issue |
6 |
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1766129285362352128 |
spelling |
ftcaltechauth:oai:authors.library.caltech.edu:114949 2023-05-15T17:31:37+02:00 Dissolved and Particulate Barium Distributions Along the US GEOTRACES North Atlantic and East Pacific Zonal Transects (GA03 and GP16): Global Implications for the Marine Barium Cycle Rahman, Shaily Shiller, Alan M. Anderson, Robert F. Charette, Matthew A. Hayes, Christopher T. Gilbert, Melissa Grissom, Karen R. Lam, Phoebe J. Ohnemus, Daniel C. Pavia, Frank J. Twining, Benjamin S. Vivancos, Sebastián M. 2022-06 application/pdf application/msword application/vnd.ms-excel https://authors.library.caltech.edu/114949/ https://authors.library.caltech.edu/114949/4/Global%20Biogeochemical%20Cycles%20-%202022%20-%20Rahman%20-%20Dissolved%20and%20Particulate%20Barium%20Distributions%20Along%20the%20US%20GEOTRACES%20North.pdf https://authors.library.caltech.edu/114949/1/2022gb007330-sup-0001-supporting%20information%20si-s01.docx https://authors.library.caltech.edu/114949/2/2022gb007330-sup-0002-table%20si-s01.xlsx https://resolver.caltech.edu/CaltechAUTHORS:20220526-391435000 en eng American Geophysical Union https://authors.library.caltech.edu/114949/4/Global%20Biogeochemical%20Cycles%20-%202022%20-%20Rahman%20-%20Dissolved%20and%20Particulate%20Barium%20Distributions%20Along%20the%20US%20GEOTRACES%20North.pdf https://authors.library.caltech.edu/114949/1/2022gb007330-sup-0001-supporting%20information%20si-s01.docx https://authors.library.caltech.edu/114949/2/2022gb007330-sup-0002-table%20si-s01.xlsx Rahman, Shaily and Shiller, Alan M. and Anderson, Robert F. and Charette, Matthew A. and Hayes, Christopher T. and Gilbert, Melissa and Grissom, Karen R. and Lam, Phoebe J. and Ohnemus, Daniel C. and Pavia, Frank J. and Twining, Benjamin S. and Vivancos, Sebastián M. (2022) Dissolved and Particulate Barium Distributions Along the US GEOTRACES North Atlantic and East Pacific Zonal Transects (GA03 and GP16): Global Implications for the Marine Barium Cycle. Global Biogeochemical Cycles, 36 (6). Art. No. e2022GB007330. ISSN 0886-6236. doi:10.1029/2022gb007330. https://resolver.caltech.edu/CaltechAUTHORS:20220526-391435000 <https://resolver.caltech.edu/CaltechAUTHORS:20220526-391435000> cc_by CC-BY Article PeerReviewed 2022 ftcaltechauth https://doi.org/10.1029/2022gb007330 2022-07-07T17:53:24Z Processes controlling dissolved barium (dBa) were investigated along the GEOTRACES GA03 North Atlantic and GP16 Eastern Tropical Pacific transects, which traversed similar physical and biogeochemical provinces. Dissolved Ba concentrations are lowest in surface waters (∼35–50 nmol kg⁻¹) and increase to 70–80 and 140–150 nmol kg⁻¹ in deep waters of the Atlantic and Pacific transects, respectively. Using water mass mixing models, we estimate conservative mixing that accounts for most of dBa variability in both transects. To examine nonconservative processes, particulate excess Ba (pBa_(xs)) formation and dissolution rates were tracked by normalizing particulate excess ²³⁰Th activities. Th-normalized pBa_(xs) fluxes, with barite as the likely phase, have subsurface maxima in the top 1,000 m (∼100–200 μmol m⁻² year⁻¹ average) in both basins. Barite precipitation depletes dBa within oxygen minimum zones from concentrations predicted by water mass mixing, whereas inputs from continental margins, particle dissolution in the water column, and benthic diffusive flux raise dBa above predications. Average pBa_(xs) burial efficiencies along GA03 and GP16 are ∼37% and 17%–100%, respectively, and do not seem to be predicated on barite saturation indices in the overlying water column. Using published values, we reevaluate the global freshwater dBa river input as 6.6 ± 3.9 Gmol year⁻¹. Estuarine mixing processes may add another 3–13 Gmol year⁻¹. Dissolved Ba inputs from broad shallow continental margins, previously unaccounted for in global marine summaries, are substantial (∼17 Gmol year⁻¹), exceeding terrestrial freshwater inputs. Revising river and shelf dBa inputs may help bring the marine Ba isotope budget more into balance. Article in Journal/Newspaper North Atlantic Caltech Authors (California Institute of Technology) Pacific Global Biogeochemical Cycles 36 6 |