Surface Ocean Biogeochemistry Regulates the Impact of Anthropogenic Aerosol Fe Deposition on the Cycling of Iron and Iron Isotopes in the North Pacific

Konig, D, Conway, TM, Hamilton, DS and Tagliabue, A ORCID: 0000-0002-3572-3634 (2022) Surface Ocean Biogeochemistry Regulates the Impact of Anthropogenic Aerosol Fe Deposition on the Cycling of Iron and Iron Isotopes in the North Pacific GEOPHYSICAL RESEARCH LETTERS, 49 (13). e2022GL098016-. ISSN 0094-8276, 1944-8007

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Abstract

Distinctively-light isotopic signatures associated with Fe released from anthropogenic activity have been used to trace basin-scale impacts. However, this approach is complicated by the way Fe cycle processes modulate oceanic dissolved Fe (dFe) signatures (δ⁵⁶Fe<inf>diss</inf>) post deposition. Here we include dust, wildfire, and anthropogenic aerosol Fe deposition in a global ocean biogeochemical model with active Fe isotope cycling, to quantify how anthropogenic Fe impacts surface ocean dFe and δ⁵⁶Fe<inf>diss</inf>. Using the North Pacific as a natural laboratory, the response of dFe, δ⁵⁶Fe<inf>diss</inf>, and primary productivity are spatially and seasonally variable and do not simply follow the footprint of atmospheric deposition. Instead, the effect of anthropogenic Fe is regulated by the biogeochemical regime, specifically the degree of Fe limitation and rates of primary production. Overall, we find that while δ⁵⁶Fe<inf>diss</inf> does trace anthropogenic input, the response is muted by fractionation during phytoplankton uptake, but amplified by other isotopically-light Fe sources.

Item Type:	Article
Uncontrolled Keywords:	anthropogenic iron, iron isotopes, model, ocean, biogeochemistry
Divisions:	Faculty of Science & Engineering > School of Environmental Sciences
Depositing User:	Symplectic Admin
Date Deposited:	20 Jul 2022 09:04
Last Modified:	16 Jun 2026 10:21
DOI:	10.1029/2022GL098016
Open Access URL:	http://doi.org/10.1029/2022gl098016
Related Websites:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3158993
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