Richard L. Reynolds
Harland L. Goldstein
Bruce M. Moskowitz
Gayan Rubasinghege
Eshani Hettiarachchi
2019
<p><span>A large part of oceanic <a title="Learn more about Biological Production" href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/biological-production" data-mce-href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/biological-production">biological production</a> is limited by the scarcity of dissolved iron. Mineral dust <a title="Learn more about Aerosol" href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/aerosol" data-mce-href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/aerosol">aerosol</a>, processed under acidic <a title="Learn more about Meteorology" href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/meteorology" data-mce-href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/meteorology">atmospheric conditions</a>, is the primary natural source of bioavailable iron to oceanic life. However, synergistic and antagonistic effects of non-Fe-containing minerals on atmospheric processing of Fe-containing minerals and Fe <a title="Learn more about Solubilization" href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/solubilization" data-mce-href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/solubilization">solubilization</a> are poorly understood. The current study focuses on mineralogical influences of non-Fe-bearing semiconductor minerals, such as <a title="Learn more about Titanium Dioxide" href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/titanium-dioxide" data-mce-href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/titanium-dioxide">titanium dioxide</a> (TiO</span><sub>2</sub><span>), on the dissolution of iron in selected natural mineral dust aerosols under atmospherically relevant conditions. Further, the role of elevated Ti concentrations in dust is evaluated using <a title="Learn more about Magnetite" href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/magnetite" data-mce-href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/magnetite">magnetite</a>, a proxy for Fe(II) containing minerals, under both dark and light conditions. Our results highlight that relatively higher Ti:Fe ratios, regardless of their total Fe content, enhances the total iron dissolution in mineral dust aerosols as well as in magnetite. Moreover, elevated Ti percentages also yield high Fe(II) fractions in mineral dust systems under dark conditions. Upon irradiation however, dissolved Fe(II) is suppressed by high Ti levels due to the involvement of photochemical redox cycling reactions with <a title="Learn more about Hydroxyl Radical" href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/hydroxyl-radical" data-mce-href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/hydroxyl-radical">hydroxyl radicals</a> (</span><sup>•</sup><span>OH). These synergistic and antagonistic effects of Ti are further evaluated by altering the chemical composition of natural dusts with artificially added <a title="Learn more about Anatase" href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/anatase" data-mce-href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/anatase">anatase</a> (TiO</span><sub>2</sub><span>) and synthetic amorphous <a title="Learn more about Titania" href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/titania" data-mce-href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/titania">titania</a>. The current study reveals important mineralogical controls by non-Fe-bearing minerals on dust iron dissolution to better understand global iron mobilization.</span></p>
application/pdf
10.1016/j.atmosenv.2019.02.037
en
Elsevier
Bioavailable iron production in airborne mineral dust: Controls by chemical composition and solar flux
article