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Enhanced deposition of atmospheric soluble iron by intrusions of marine air masses to East Antarctica

Citation

Winton, VHL and Bowie, AR and Curran, MA and Moy, AD, Enhanced deposition of atmospheric soluble iron by intrusions of marine air masses to East Antarctica, Journal of Geophysical Research: Atmospheres, 127, (13) Article e2022JD036586. ISSN 2169-8996 (2022) [Refereed Article]


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Copyright Statement

2022. The Authors. This is an open access article under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) License, (https://creativecommons.org/licenses/by/4.0/), which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

DOI: doi:10.1029/2022JD036586

Abstract

Bio-essential iron can relieve nutrient limitation and stimulate marine productivity in the Southern Ocean. The fractional iron solubility of aerosol iron is an important variable determining iron availability for biological uptake. However, estimates of dissolved iron (dFe; iron < 0.2 μm) and the factors driving the variability of fractional iron solubility in pristine air masses are largely unquantified. To constrain inputs of fractional iron solubility to remote East Antarctic waters, dFe, total dissolvable iron (TDFe), trace elements and refractory black carbon were analyzed in a 9-year-old snow pit (2005-2014) from a new ice core site at Aurora Basin North (ABN) in Wilkes Land, East Antarctica. Extremely low annual dFe deposition fluxes were estimated (0.2 x 10-6 g m-2 y-1), while annual TDFe deposition fluxes (70 x 10-6 g m-2 y-1) were comparable to other Antarctic sites. Total dissolvable iron is dominantly sourced from mineral dust. Unlike coastal Antarctic sites where the variability of fractional iron solubility in modern snow is explained by a mixture of dust and biomass burning sources, dFe deposition and fractional iron solubility at ABN (ranging between 0.1 and 6 %) is enhanced in episodic high precipitation events from synoptic warm air masses. Enhanced fractional iron solubility reaching the high elevation site at ABN is suggested through the mechanism of cloud processing of background mineral dust that modifies the dust chemistry and increases iron dissolution during long-range transport. This study highlights a complex interplay of sources and processes that drive fractional iron solubility in pristine air masses.

Item Details

Item Type:Refereed Article
Keywords:atmospheric deposition, soluble iron, air masses, East Antarctica
Research Division:Earth Sciences
Research Group:Oceanography
Research Field:Chemical oceanography
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts)
UTAS Author:Bowie, AR (Professor Andrew Bowie)
UTAS Author:Curran, MA (Dr Mark Curran)
UTAS Author:Moy, AD (Dr Andrew Moy)
ID Code:150963
Year Published:2022
Funding Support:Australian Research Council (FT130100037)
Deposited By:Oceans and Cryosphere
Deposited On:2022-07-07
Last Modified:2022-08-09
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