Wang, R-M and Archer, C and Bowie, AR and Vance, D, Zinc and nickel isotopes in seawater from the Indian sector of the Southern Ocean: the impact of natural iron fertilization versus Southern Ocean hydrography and biogeochemistry, Chemical Geology, 511 pp. 452-464. ISSN 0009-2541 (2019) [Refereed Article]
Copyright 2018 Published by Elsevier B.V.
Zinc and Ni concentrations show depth distributions and relationships to major nutrients that are very similar to published data from the Atlantic sector of the Southern Ocean, away from island fertilization. As in the Atlantic sector, and other regions outside the Southern Ocean, there is a slight minimum in δ66Zn at about 100–150 m depth and a slightly heavier value at the surface. At the KEOPS-2 sites, the light sub-surface Zn isotopes occur at the depth level where measured chl-a has declined to near zero. The heaviest Zn isotope values in either the Atlantic or Indian sectors occur in bottom waters, are associated with samples that show high dissolved Si relative to Zn. These latter represent possible evidence for a heavy input directly to deep water or from sediment, and the Zn-Si-δ66Zn systematics are consistent with a source in diatom opal. Nickel concentrations show much less variation than those of Zn, with the most depleted surface value only 15–20% lower than those in upwelled deep water in the Southern Ocean. These small variations in Ni concentration are associated with no significant variability in Ni isotopes, as also previously observed in the Atlantic sector.
Overall, the key feature of the dataset is the apparent absence of any significant impact of natural Fe fertilization on the distribution of Zn and Ni, with the dominant control being the station location relative to the Polar Front in both the Atlantic and Indian sectors. Zinc and Ni isotopes are invariant in surface waters, whether inside or outside the fertilized zone and whether south or north of the Polar Front.
This article is part of a special issue entitled: "Cycles of trace elements and isotopes in the ocean – GEOTRACES and beyond" - edited by Tim M. Conway, Tristan Horner, Yves Plancherel, and Aridane G. González.
|Item Type:||Refereed Article|
|Keywords:||zinc, nickel, isotopes, Southern Ocean, KEOPS-2, Kerguelen Island, natural iron fertilization|
|Research Division:||Earth Sciences|
|Research Field:||Chemical oceanography|
|Objective Division:||Environmental Management|
|Objective Group:||Marine systems and management|
|Objective Field:||Measurement and assessment of marine water quality and condition|
|UTAS Author:||Bowie, AR (Professor Andrew Bowie)|
|Year Published:||2019 (online first 2018)|
|Web of Science® Times Cited:||17|
|Deposited By:||Oceans and Cryosphere|
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