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Dry season aerosol iron solubility in tropical northern Australia

Citation

Winton, VHL and Edwards, R and Bowie, AR and Keywood, M and Williams, AG and Chambers, SD and Selleck, PW and Desservettaz, M and Mallet, MD and Paton-Walsh, C, Dry season aerosol iron solubility in tropical northern Australia, Atmospheric Chemistry and Physics, 16, (19) pp. 12829-12848. ISSN 1680-7316 (2016) [Refereed Article]


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Copyright 2016 Author(s) Licensed under Creative Commons Attribution 3.0 Unported https://creativecommons.org/licenses/by/3.0/legalcode

DOI: doi:10.5194/acp-16-12829-2016

Abstract

Marine nitrogen fixation is co-limited by the supply of iron (Fe) and phosphorus in large regions of the global ocean. The deposition of soluble aerosol Fe can initiate nitrogen fixation and trigger toxic algal blooms in nitrate-poor tropical waters. We present dry season soluble Fe data from the Savannah Fires in the Early Dry Season (SAFIRED) campaign in northern Australia that reflects coincident dust and biomass burning sources of soluble aerosol Fe. The mean soluble and total aerosol Fe concentrations were 40 and 500 ng m−3 respectively. Our results show that while biomass burning species may not be a direct source of soluble Fe, biomass burning may substantially enhance the solubility of mineral dust. We observed fractional Fe solubility up to 12 % in mixed aerosols. Thus, Fe in dust may be more soluble in the tropics compared to higher latitudes due to higher concentrations of biomass-burning-derived reactive organic species in the atmosphere. In addition, biomass-burning-derived particles can act as a surface for aerosol Fe to bind during atmospheric transport and subsequently be released to the ocean upon deposition. As the aerosol loading is dominated by biomass burning emissions over the tropical waters in the dry season, additions of biomass-burning-derived soluble Fe could have harmful consequences for initiating nitrogen-fixing toxic algal blooms. Future research is required to quantify biomass-burning-derived particle sources of soluble Fe over tropical waters.

Item Details

Item Type:Refereed Article
Keywords:aerosols, iron, solubility, tropical Australia
Research Division:Earth Sciences
Research Group:Atmospheric Sciences
Research Field:Atmospheric Aerosols
Objective Division:Environment
Objective Group:Atmosphere and Weather
Objective Field:Atmospheric Processes and Dynamics
Author:Bowie, AR (Associate Professor Andrew Bowie)
ID Code:113161
Year Published:2016
Funding Support:Australian Research Council (FT130100037)
Web of Science® Times Cited:2
Deposited By:Centre for Oceans and Cryosphere
Deposited On:2016-12-14
Last Modified:2017-02-28
Downloads:23 View Download Statistics

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