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Abstract

In this study we investigated the distribution of dissolved and particulate zinc (dZn and pZn respectively) and its isotopes in the Subantarctic Zone as part of a Geotraces Process voyage. dZn and pZn depth profiles contrasted each other, with dZn showing depletion within the euphotic zone while pZn profiles showed enrichment. Fitting a power law equation to the pZn profiles produced an attenuation factor of 0.82, which contrasted values for particulate phosphorus, cadmium and copper. The results indicate that zinc has a longer regeneration length scale than phosphorus and cadmium, but shorter than copper. The differential regeneration of pZn relative to that of particulate phosphorus likely explains why dZn appears to have a deeper regeneration profile than that of phosphate. The dZn isotope (δ66Zndissolved) profiles collected across the Subantarctic Zone showed differing profile structures. For one station collected within an isolated cold-core eddy (CCE), δ66Zndissolved showed surface enrichment relative to deep waters. The corresponding pZn isotope profiles within the CCE did not show enrichment; rather, they were subtly depleted in surface waters and then converged to similar values at depth. Zinc isotope fractionation can be explained through a combination of fractionation processes associated with uptake by phytoplankton, zinc complexation by natural organic ligands and zinc regeneration from particulate matter.

Item Type:	Article
Authors/Creators:	Ellwood, MJ and Strzepek, R and Chen, X and Trull, TW and Boyd, PW
Keywords:	zinc, isotope fractionation, biogeochemistry, Southern Ocean
Journal or Publication Title:	Marine and Freshwater Research
Publisher:	C S I R O Publishing
ISSN:	1323-1650
DOI / ID Number:	10.1071/MF19200
Copyright Information:	Copyright CSIRO 2020. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) http://creativecommons.org/licenses/by-nc-nd/4.0/
Related URLs:	Google Scholar: Strzepek, R Google Scholar: Boyd, PW UTAS Profile: Boyd, PW
Item Statistics:	View statistics for this item

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