Pyrogenic iron: The missing link to high iron solubility in aerosols

Akinori Ito , Stelios Myriokefalitakis (1) , Maria Kanakidou (1) , Natalie Mahowald (2) , Rachel Scanza , Douglas Hamilton , Alex Baker , Timothy D Jickells (3) , Manmohan Sarin , Srinivas Bikkina , Yuan Gao (4) , Rachel Shelley , Clifton Buck , William Landing (5) , Andrew R. Bowie (6) , Morgane Perron , Cécile Guieu (7) , Nicholas Meskhidze , Matthew Johnson (8) , Yan Feng , Jasper Kok , Athanasios Nenes (9) , Robert Duce

1 ECPL - Environmental Chemical Processes Laboratory [Heraklion]
2 EAS - Department of Earth and Atmospheric Sciences [Ithaca)
3 UEA - University of East Anglia [Norwich]
4 IRDL - Institut de Recherche Dupuy de Lôme
5 FSU - Florida State University [Tallahassee]
6 ACE-CRC - Antarctic Climate and Ecosystems Cooperative Research Centre
7 LOV - Laboratoire d'océanographie de Villefranche
8 Durham University
9 Institute for Environmental Research & Sustainable Development

Atmospheric deposition is a source of potentially bioavailable iron (Fe) and thus can partially control biological productivity in large parts of the ocean. However, the explanation of observed high aerosol Fe solubility compared to that in soil particles is still controversial, as several hypotheses have been proposed to explain this observation. Here, a statistical analysis of aerosol Fe solubility estimated from four models and observations compiled from multiple field campaigns suggests that pyrogenic aerosols are the main sources of aerosols with high Fe solubility at low concentration. Additionally, we find that field data over the Southern Ocean display a much wider range in aerosol Fe solubility compared to the models, which indicate an underestimation of labile Fe concentrations by a factor of 15. These findings suggest that pyrogenic Fe-containing aerosols are important sources of atmospheric bioavailable Fe to the open ocean and crucial for predicting anthropogenic perturbations to marine productivity.

Domaines: Océan, Atmosphère

Akinori Ito, Stelios Myriokefalitakis, Maria Kanakidou, Natalie Mahowald, Rachel Scanza, et al.. Pyrogenic iron: The missing link to high iron solubility in aerosols. Science Advances , 2019, 5 (5), pp.eaau7671. ⟨10.1126/sciadv.aau7671⟩. ⟨hal-02366983⟩