Tagliabue A. auteur aut IRD Bopp L. auteur aut IRD Aumont Olivier auteur aut IRD text journalArticle eng text/pdf reformatted digital access Dust deposition of iron is thought to be an important control on ocean biogeochemistry and air-sea CO2 exchange. In this study, we examine the impact of a large scale, yet climatically realistic, reduction in the aeolian Fe input during a 240 year transient simulation. In contrast to previous studies, we find that the ocean biogeochemical cycles of carbon and nitrogen are relatively insensitive (globally) to a 60% reduction in Fe input from dust. Net primary productivity (NPP) is reduced in the Fe limited regions, but the excess macronutrients that result are able to fuel additional NPP elsewhere. Overall, NPP and air-sea CO2 exchange are only reduced by around 3% between 1860 and 2100. While the nitrogen cycle is perturbed more significantly (by similar to 15%), reduced N-2 fixation is balanced by a concomitant decline in denitrification. Feedbacks between N-2 fixation and denitrification are controlled by variability in surface utilization of inorganic nitrogen and subsurface oxygen consumption, as well as the direct influence of Fe on N-2 fixation. Overall, there is relatively little impact of reduced aeolian Fe input (< 4%) on cumulative CO2 fluxes over 240 years. The lower sensitivity of our model to changes in dust input is primarily due to the more detailed representation of the continental shelf Fe, which was absent in previous models. specialized 032 5 1 11-24 2008 1726-4170 https://www.documentation.ird.fr/hor/fdi:010040934 1726-4170 [F B010040934] https://www.documentation.ird.fr/hor/fdi:010040934 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/divers17-09/010040934.pdf IRD - Base Horizon / Pleins textes 2008-03-31 2017-10-03 fdi:010040934 fre