The impact of different external sources of iron on the global carbon cycle

Variable supply of iron to the ocean is often invoked to explain part of past changes in atmospheric CO2 (CO2atm). Using model simulations, we find that CO2atm is sensitive on the order of 15, 2, and 1 ppm to sedimentary, dust, and hydrothermal iron input. CO2atm is insensitive to dust because it is...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: TAGLIABUE, Alessandro, AUMONT, Olivier, BOPP, Laurent
Format: Other/Unknown Material
Language:English
Published: American Geophysical Union 2014
Subjects:
ocean
biogeochemistry
phytoplankton
iron
carbon
Planète et Univers [physics]/Sciences de la Terre/Océanographie
Southern Ocean
Online Access:https://oskar-bordeaux.fr/handle/20.500.12278/30340
https://doi.org/10.1002/2013GL059059
Description
Summary:Variable supply of iron to the ocean is often invoked to explain part of past changes in atmospheric CO2 (CO2atm). Using model simulations, we find that CO2atm is sensitive on the order of 15, 2, and 1 ppm to sedimentary, dust, and hydrothermal iron input. CO2atm is insensitive to dust because it is not the major iron input to the Southern Ocean. Modifications to the relative export of Si(OH)4 to low latitudes are opposite to those predicted previously. Although hydrothermalism is the major control on the iron inventory in ~25% of the ocean, it remains restricted to the deep ocean, with minor effects on CO2atm. Nevertheless, uncertainties regarding the iron-binding ligand pool can have significant impacts on CO2atm. Ongoing expansion of iron observations as part of GEOTRACES will be invaluable in refining these results.

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