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Enhanced iron flux to Antarctic sea ice via dust deposition from ice-free coastal areas

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Duprat, L, Kanna, N, Janssens, J, Roukaerts, A, Deman, F, Townsend, AT ORCID: 0000-0002-2972-2678, Meiners, KM, van der Merwe, P ORCID: 0000-0002-7428-8030 and Lannuzel, D ORCID: 0000-0001-6154-1837 2019 , 'Enhanced iron flux to Antarctic sea ice via dust deposition from ice-free coastal areas' , Journal of Geophysical Research: Oceans, vol. 124, no. 12 , pp. 8538-8557 , doi: 10.1029/2019JC015221.

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Abstract

Antarctic sea ice is an important temporal reservoir of iron which can boost primary production in the marginal ice zone during the seasonal melt. While studies have reported that Antarctic fast ice bears high concentrations of iron due to the proximity to coastal sources, less clear are the biogeochemical changes this iron pool undergoes during late spring. Here we describe a 3‐week time series of physical and biogeochemical data, including iron, from first‐year coastal fast ice sampled near Davis Station (Prydz Bay, East Antarctica) during late austral spring 2015. Our study shows that dissolved and particulate iron concentrations in sea ice were up to two orders of magnitude higher than in under‐ice seawater. Furthermore, our results indicate a significant contribution of lithogenic iron from the Vestfold Hills (as deduced from the comparison with crustal element ratios) to the particulate iron pool in fast ice after a blizzard event halfway through the time series. Windblown dust represented approximately 75% of the particulate iron found in the ice and is a potential candidate for keeping concentrations of soluble iron stable during our observations. These results suggest that iron entrapped during ice formation, likely from sediments, as well as local input of coastal dust, supports primary productivity in Davis fast ice. As ice‐free land areas are likely to expand over the course of the century, this work highlights the need to quantify iron inputs from continental Antarctic dust and its bioavailability for ice algae and phytoplankton.

Item Type: Article
Authors/Creators:Duprat, L and Kanna, N and Janssens, J and Roukaerts, A and Deman, F and Townsend, AT and Meiners, KM and van der Merwe, P and Lannuzel, D
Keywords: sea ice, fast ice, Fe, dust, phytoplankton, algae
Journal or Publication Title: Journal of Geophysical Research: Oceans
Publisher: Wiley-Blackwell Publishing Inc.
ISSN: 2169-9275
DOI / ID Number: 10.1029/2019JC015221
Copyright Information:

Copyright 2019 American Geophysical Union

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