Yttrium and rare earth element partitioning in seawaters from the Bay of Bengal

The dissolved Yttrium (Y) and Rare Earth Element (REE) concentrations of seawater samples collected along a north-south hydrological transect within the Bay of Bengal (BoB) have been analyzed to estimate contributions of the Ganges and Brahmaputra (G-B) river inputs to the dissolved REE distribution...

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Bibliographic Details
Published in:Geochemistry, Geophysics, Geosystems
Main Authors: Yu, Zhaojie, Colin, Christophe, Douville, Eric, Meynadier, Laure, Duchamp-alphonse, Stephanie, Sepulcre, Sophie, Wan, Shiming, Song, Lina, Wu, Qiong, Xu, Zhaokai, Bassinot, Frank
Format: Article in Journal/Newspaper
Language:English
Published: Amer Geophysical Union 2017
Subjects:
Antarctic
Indian
Antarc*
Online Access:https://archimer.ifremer.fr/doc/00377/48845/49277.pdf
https://archimer.ifremer.fr/doc/00377/48845/49279.pdf
https://doi.org/10.1002/2016GC006749
https://archimer.ifremer.fr/doc/00377/48845/
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Summary:The dissolved Yttrium (Y) and Rare Earth Element (REE) concentrations of seawater samples collected along a north-south hydrological transect within the Bay of Bengal (BoB) have been analyzed to estimate contributions of the Ganges and Brahmaputra (G-B) river inputs to the dissolved REE distribution of the Northern Indian Ocean. Surface water masses of the BoB are characterized by Y/Ho ratios (84) intermediate between the G-B river suspended sediment (41) and water mass from the South Indian Ocean (93). Co-variation of MREE (Middle REE, Sm) and LREE (Light REE, La) concentrations suggests that the dissolved REEs in surface waters (upper 100 m depth) of the BoB (Sm/La = 0.21) appear to derive mainly from the freshwater discharge of the G-B river system. In contrast, values obtained in the intermediate and deep-waters (Sm/La = 0.14) suggest a mixing of dissolved REEs deriving from the release of G-B river suspended particles (Sm/La = 0.16) and the contribution of Antarctic Bottom Water (AABW) (Sm/La = 0.12). Consequently, we propose that MREE/MREE* ratios in the BoB waters could be an accurate proxy to trace lithogenic inputs from the G-B river system. The dissolved and particle re-mineralization Nd fluxes from G-B river system are calculated to constitute about 9% and 4% of the global dissolved river discharge and ‘Boundary inputs' flux. Our estimation indicates that the massive G-B river system inputs could greatly alter the dissolved REEs distribution in the BoB and contribute to the dissolved REEs budget in the ocean

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