Natural iron fertilization by shallow hydrothermal sources fuels diazotroph blooms in the ocean Bonnet Sophie auteur aut IRD Guieu C. auteur aut IRD Taillandier V. auteur aut IRD Boulart C. auteur aut IRD Bouruet-Aubertot P. auteur aut IRD Gazeau F. auteur aut IRD Scalabrin C. auteur aut IRD Bressac M. auteur aut IRD Knapp A. N. auteur aut IRD Cuypers Y. auteur aut IRD Gonzalez-Santana D. auteur aut IRD Forrer H. J. auteur aut IRD Grisoni J. M. auteur aut IRD Grosso O. auteur aut IRD Habasque Jérémie auteur aut IRD Jardin-Camps M. auteur aut IRD Leblond N. auteur aut IRD Le Moigne F. A. C. auteur aut IRD Lebourges Dhaussy Anne auteur aut IRD Lory Caroline auteur aut IRD Nunige S. auteur aut IRD Pulido-Villena E. auteur aut IRD Rizzo A. L. auteur aut IRD Sarthou G. auteur aut IRD Tilliette C. auteur aut IRD text journalArticle eng text/pdf born digital access Iron is an essential nutrient that regulates productivity in similar to 30% of the ocean. Compared with deep (>2000 meter) hydrothermal activity at mid-ocean ridges that provide iron to the ocean's interior, shallow (<500 meter) hydrothermal fluids are likely to influence the surface's ecosystem. However, their effect is unknown. In this work, we show that fluids emitted along the Tonga volcanic arc (South Pacific) have a substantial impact on iron concentrations in the photic layer through vertical diffusion. This enrichment stimulates biological activity, resulting in an extensive patch of chlorophyll (360,000 square kilometers). Diazotroph activity is two to eight times higher and carbon export fluxes are two to three times higher in iron-enriched waters than in adjacent unfertilized waters. Such findings reveal a previously undescribed mechanism of natural iron fertilization in the ocean that fuels regional hotspot sinks for atmospheric CO2. specialized TONGA 036 032 Science 380 6647 812-817 2023 0036-8075 https://www.documentation.ird.fr/hor/fdi:010088256 10.1126/science.abq4654 0036-8075 [F B010088256] https://www.documentation.ird.fr/hor/fdi:010088256 https://www.documentation.ird.fr/intranet/publi/2023-08/010088256.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2023-08-25 2025-02-24 fdi:010088256 fre