Tracing Water Mass Mixing From the Equatorial to the North Pacific Ocean With Dissolved Neodymium Isotopes and Concentrations
The sluggish water mass transport in the deeper North Pacific Ocean complicates the assessment of formation, spreading and mixing of surface, intermediate and deep-water masses based on standard hydrographic parameters alone. Geochemical tracers sensitive to water mass provenance and mixing allow to...
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Online Access: | http://dx.doi.org/10.3389/fmars.2020.603761 https://www.frontiersin.org/articles/10.3389/fmars.2020.603761/full |
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crfrontiers:10.3389/fmars.2020.603761 2024-06-23T07:47:58+00:00 Tracing Water Mass Mixing From the Equatorial to the North Pacific Ocean With Dissolved Neodymium Isotopes and Concentrations Fuhr, Michael Laukert, Georgi Yu, Yang Nürnberg, Dirk Frank, Martin Bundesministerium für Bildung und Forschung 2021 http://dx.doi.org/10.3389/fmars.2020.603761 https://www.frontiersin.org/articles/10.3389/fmars.2020.603761/full unknown Frontiers Media SA https://creativecommons.org/licenses/by/4.0/ Frontiers in Marine Science volume 7 ISSN 2296-7745 journal-article 2021 crfrontiers https://doi.org/10.3389/fmars.2020.603761 2024-06-11T04:07:40Z The sluggish water mass transport in the deeper North Pacific Ocean complicates the assessment of formation, spreading and mixing of surface, intermediate and deep-water masses based on standard hydrographic parameters alone. Geochemical tracers sensitive to water mass provenance and mixing allow to better characterize the origin and fate of the prevailing water masses. Here, we present dissolved neodymium (Nd) isotope compositions (ε Nd ) and concentrations ([Nd]) obtained along a longitudinal transect at ∼180°E from ∼7°S to ∼50°N. The strongest contrast in Nd isotope signatures is observed in equatorial regions between surface waters (ε Nd ∼0 at 4.5°N) and Lower Circumpolar Deep Water (LCDW) prevailing at 4500 m depth (ε Nd = −6.7 at 7.2°N). The Nd isotope compositions of equatorial surface and subsurface waters are strongly influenced by regional inputs from the volcanic rocks surrounding the Pacific, which facilitates the identification of the source regions of these waters and seasonal changes in their advection along the equator. Highly radiogenic weathering inputs from Papua-New-Guinea control the ε Nd signature of the equatorial surface waters and strongly alter the ε Nd signal of Antarctic Intermediate Water (AAIW) by sea water-particle interactions leading to an ε Nd shift from −5.3 to −1.7 and an increase in [Nd] from 8.5 to 11.0 pmol/kg between 7°S and 15°N. Further north in the open North Pacific, mixing calculations based on ε Nd , [Nd] and salinity suggest that this modification of the AAIW composition has a strong impact on intermediate water ε Nd signatures of the entire region allowing for improved identification of the formation regions and pathways of North Pacific Intermediate Water (NPIW). The deep-water Nd isotope signatures indicate a southern Pacific origin and subsequent changes along its trajectory resulting from a combination of water mass mixing, vertical processes and Nd release from seafloor sediments, which precludes Nd isotopes as quantitative tracers of deep-water mass mixing. ... Article in Journal/Newspaper Antarc* Antarctic Frontiers (Publisher) Antarctic Pacific Frontiers in Marine Science 7 |
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Frontiers (Publisher) |
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description |
The sluggish water mass transport in the deeper North Pacific Ocean complicates the assessment of formation, spreading and mixing of surface, intermediate and deep-water masses based on standard hydrographic parameters alone. Geochemical tracers sensitive to water mass provenance and mixing allow to better characterize the origin and fate of the prevailing water masses. Here, we present dissolved neodymium (Nd) isotope compositions (ε Nd ) and concentrations ([Nd]) obtained along a longitudinal transect at ∼180°E from ∼7°S to ∼50°N. The strongest contrast in Nd isotope signatures is observed in equatorial regions between surface waters (ε Nd ∼0 at 4.5°N) and Lower Circumpolar Deep Water (LCDW) prevailing at 4500 m depth (ε Nd = −6.7 at 7.2°N). The Nd isotope compositions of equatorial surface and subsurface waters are strongly influenced by regional inputs from the volcanic rocks surrounding the Pacific, which facilitates the identification of the source regions of these waters and seasonal changes in their advection along the equator. Highly radiogenic weathering inputs from Papua-New-Guinea control the ε Nd signature of the equatorial surface waters and strongly alter the ε Nd signal of Antarctic Intermediate Water (AAIW) by sea water-particle interactions leading to an ε Nd shift from −5.3 to −1.7 and an increase in [Nd] from 8.5 to 11.0 pmol/kg between 7°S and 15°N. Further north in the open North Pacific, mixing calculations based on ε Nd , [Nd] and salinity suggest that this modification of the AAIW composition has a strong impact on intermediate water ε Nd signatures of the entire region allowing for improved identification of the formation regions and pathways of North Pacific Intermediate Water (NPIW). The deep-water Nd isotope signatures indicate a southern Pacific origin and subsequent changes along its trajectory resulting from a combination of water mass mixing, vertical processes and Nd release from seafloor sediments, which precludes Nd isotopes as quantitative tracers of deep-water mass mixing. ... |
author2 |
Bundesministerium für Bildung und Forschung |
format |
Article in Journal/Newspaper |
author |
Fuhr, Michael Laukert, Georgi Yu, Yang Nürnberg, Dirk Frank, Martin |
spellingShingle |
Fuhr, Michael Laukert, Georgi Yu, Yang Nürnberg, Dirk Frank, Martin Tracing Water Mass Mixing From the Equatorial to the North Pacific Ocean With Dissolved Neodymium Isotopes and Concentrations |
author_facet |
Fuhr, Michael Laukert, Georgi Yu, Yang Nürnberg, Dirk Frank, Martin |
author_sort |
Fuhr, Michael |
title |
Tracing Water Mass Mixing From the Equatorial to the North Pacific Ocean With Dissolved Neodymium Isotopes and Concentrations |
title_short |
Tracing Water Mass Mixing From the Equatorial to the North Pacific Ocean With Dissolved Neodymium Isotopes and Concentrations |
title_full |
Tracing Water Mass Mixing From the Equatorial to the North Pacific Ocean With Dissolved Neodymium Isotopes and Concentrations |
title_fullStr |
Tracing Water Mass Mixing From the Equatorial to the North Pacific Ocean With Dissolved Neodymium Isotopes and Concentrations |
title_full_unstemmed |
Tracing Water Mass Mixing From the Equatorial to the North Pacific Ocean With Dissolved Neodymium Isotopes and Concentrations |
title_sort |
tracing water mass mixing from the equatorial to the north pacific ocean with dissolved neodymium isotopes and concentrations |
publisher |
Frontiers Media SA |
publishDate |
2021 |
url |
http://dx.doi.org/10.3389/fmars.2020.603761 https://www.frontiersin.org/articles/10.3389/fmars.2020.603761/full |
geographic |
Antarctic Pacific |
geographic_facet |
Antarctic Pacific |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Frontiers in Marine Science volume 7 ISSN 2296-7745 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3389/fmars.2020.603761 |
container_title |
Frontiers in Marine Science |
container_volume |
7 |
_version_ |
1802638301895589888 |