Full text not available from this repository.

Abstract

Since Antarctic sea ice covers an area larger than the Antarctic continent itself, the discovery that it can fertilize the Southern Ocean with iron (Fe) has fostered a new breadth of research in recent years. In order to test the hypothesis that Fe-binding organic ligands control the distribution of dissolved iron (DFe) in Antarctic pack ice, iron organic speciation was investigated in samples collected during the Sea Ice Physics and Ecosystem eXperiment-2 (SIPEX-2) voyage in Austral winter/spring 2012. Dissolved Fe was measured using sector field inductively coupled plasma mass spectrometry, and iron organic speciation parameters were determined by competitive ligand equilibration - adsorptive cathodic stripping voltammetry method, using 1-nitroso-2-naphthol (NN) as the added ligand. The concentration of Fe-binding organic ligands (Lt) ranged from 4.9 nM to 41 nM (average of 14.9 ± 8.4 nM, n = 34), and was always higher than the corresponding DFe (average of 7.5 ± 4.5 nM, n = 34). Conditional stability constants (log K′Fe’L = 11.7–13.0) were similar to those previously observed in land-fast ice. Concentrations of DFe and Lt displayed similar depth profiles; their strong correlation (Spearman's ρ = 0.80, p 1). Estimates showed that pack ice would have released 0.45 μmol/m2/d of Lt during spring melt, 0.21 μmol/m2/d of which are free from Fe binding, and hence available for further complexation. Therefore, it is suggested that this excess of Fe-free ligands may play a key role in controlling the solubility of free or newly formed Fe in surface waters before the peak of primary production, outcompeting the Fe-binding organic ligands already present in seawater.

Item Type:	Article
Authors/Creators:	Genovese, C and Grotti, M and Pittaluga, J and Ardini, F and Janssens, J and Wuttig, K and Moreau, S and Lannuzel, D
Keywords:	sea ice, ligands, iron, Antarctica
Journal or Publication Title:	Marine Chemistry
Publisher:	Elsevier Science Bv
ISSN:	0304-4203
DOI / ID Number:	https://doi.org/10.1016/j.marchem.2018.04.005
Copyright Information:	© 2018 Elsevier B.V. All rights reserved.
Related URLs:	Google Scholar: Wuttig, K UTAS Profile: Wuttig, K Google Scholar: Moreau, S Google Scholar: Lannuzel, D UTAS Profile: Lannuzel, D
Item Statistics:	View statistics for this item

Actions (login required)

Item Control Page