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Article Dans Une Revue Science Advances Année : 2023

Chasing iron bioavailability in the Southern Ocean: Insights from Phaeocystis antarctica and iron speciation

Résumé

Dissolved iron (dFe) availability limits the uptake of atmospheric CO 2 by the Southern Ocean (SO) biological pump. Hence, any change in bioavailable dFe in this region can directly influence climate. On the basis of Fe uptake experiments with Phaeocystis antarctica , we show that the range of dFe bioavailability in natural samples is wider (<1 to ~200% compared to free inorganic Fe′) than previously thought, with higher bioavailability found near glacial sources. The degree of bioavailability varied regardless of in situ dFe concentration and depth, challenging the consensus that sole dFe concentrations can be used to predict Fe uptake in modeling studies. Further, our data suggest a disproportionately major role of biologically mediated ligands and encourage revisiting the role of humic substances in influencing marine Fe biogeochemical cycling in the SO. Last, we describe a linkage between in situ dFe bioavailability and isotopic signatures that, we anticipate, will stimulate future research.
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Origine : Publication financée par une institution
Licence : CC BY NC - Paternité - Pas d'utilisation commerciale

Dates et versions

hal-04148414 , version 1 (03-07-2023)

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Paternité - Pas d'utilisation commerciale

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Marion Fourquez, David J Janssen, Tim M Conway, Damien Cabanes, Michael J Ellwood, et al.. Chasing iron bioavailability in the Southern Ocean: Insights from Phaeocystis antarctica and iron speciation: Bioassays, iron speciation, and isotopic analysis uncover a significant range of variability in dissolved iron bioavailability in the Southern Ocean. Science Advances , 2023, 9 (26), ⟨10.1126/sciadv.adf9696⟩. ⟨hal-04148414⟩
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