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137719 - Distinct iron cycling in a Southern Ocean eddy.pdf (902.03 kB)

Distinct iron cycling in a Southern Ocean eddy

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posted on 2023-05-20, 11:29 authored by Ellwood, MJ, Robert StrzepekRobert Strzepek, Peter StruttonPeter Strutton, Trull, TW, Fourquez, M, Philip BoydPhilip Boyd
Mesoscale eddies are ubiquitous in the iron-limited Southern Ocean, controlling ocean-atmosphere exchange processes, however their influence on phytoplankton productivity remains unknown. Here we probed the biogeochemical cycling of iron (Fe) in a cold-core eddy. In-eddy surface dissolved Fe (dFe) concentrations and phytoplankton productivity were exceedingly low relative to external waters. In-eddy phytoplankton Fe-to-carbon uptake ratios were elevated 2–6 fold, indicating upregulated intracellular Fe acquisition resulting in a dFe residence time of ~1 day. Heavy dFe isotope values were measured for in-eddy surface waters highlighting extensive trafficking of dFe by cells. Below the euphotic zone, dFe isotope values were lighter and coincident with peaks in recycled nutrients and cell abundance, indicating enhanced microbially-mediated Fe recycling. Our measurements show that the isolated nature of Southern Ocean eddies can produce distinctly different Fe biogeochemistry compared to surrounding waters with cells upregulating iron uptake and using recycling processes to sustain themselves.

History

Publication title

Nature Communications

Volume

11

Article number

825

Number

825

Pagination

1-8

ISSN

2041-1723

Department/School

Institute for Marine and Antarctic Studies

Publisher

Nature Publishing Group

Place of publication

United Kingdom

Rights statement

© The Author(s) 2020. Licensed under Creative Commons Attribution 4.0 International (CC BY 4.0) http://creativecommons.org/licenses/by/4.0/

Repository Status

  • Open

Socio-economic Objectives

Climate change mitigation strategies

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