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Nutrient distribution in East Antarctic summer sea ice: a potential iron contribution from glacial basal melt

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posted on 2023-05-20, 20:39 authored by Duprat, L, Matthew CorkillMatthew Corkill, Genovese, C, Ashley TownsendAshley Townsend, Moreau, S, Klaus MeinersKlaus Meiners, Delphine LannuzelDelphine Lannuzel

Antarctic sea ice can incorporate high levels of iron (Fe) during its formation and has been suggested as an important source of this essential micronutrient to Southern Ocean surface waters during the melt season. Over the last decade, a limited number of studies have quantified the Fe pool in Antarctic sea ice, with a focus on late winter and spring. Here we study the distribution of operationally defined dissolved and particulate Fe from nine sites sampled between Wilkes Land and King George V Land during austral summer 2016/2017. Results point toward a net heterotrophic sea‐ice community, consistent with the observed nitrate limitation (<1 μM). We postulate that the recycling of the high particulate Fe pool in summer sea ice supplies sufficient (∼3 nM) levels of dissolved Fe to sustain ice algal growth. The remineralization of particulate Fe is likely favored by high concentrations of exopolysaccharides (113–16,290 μg xeq L−1) which can serve as a hotspot for bacterial activity. Finally, results indicate a potential relationship between glacial meltwater discharged from the Moscow University Ice Shelf and the occurrence of Fe‐rich (∼4.3 μM) platelet ice in its vicinity. As climate change is expected to result in enhanced Fe‐rich glacial discharge and changes in summer sea‐ice extent and quality, the processes influencing Fe distribution in sea ice that persists into summer need to be better constrained.

History

Publication title

JGR Oceans

Volume

125

Issue

12

Article number

e2020JC016130

Number

e2020JC016130

Pagination

1-19

ISSN

2169-9275

Department/School

Institute for Marine and Antarctic Studies

Publisher

Wiley-Blackwell Publishing Inc.

Place of publication

United States

Rights statement

Copyright 2020 The Authors. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Repository Status

  • Open

Socio-economic Objectives

Antarctic and Southern Ocean oceanic processes

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