Chowdhury S. auteur aut IRD Raes E. auteur aut IRD Horstmann C. auteur aut IRD Ahmed A. auteur aut IRD Ridame C. auteur aut IRD Metzl N. auteur aut IRD Bhavya P. S. auteur aut IRD Sato T. auteur aut IRD Shiozaki T. auteur aut IRD Bonnet Sophie auteur aut IRD Loscher C. R. auteur aut IRD Singh A. auteur aut IRD Benavides Mar auteur aut IRD text journalArticle eng text/pdf reformatted digital access Dinitrogen (N-2) fixation provides the major source of reactive nitrogen in the open ocean, sustaining biological productivity. The Indian Ocean (IO) covers 22% of the ocean surface, while it only represents 1% of the global diazotroph database. Hence, constraining the sources of nitrogen in the IO is crucial. Here, we compile three decades of N-2 fixation and diazotroph DNA data in the IO. Our analysis reveals basin-scale yearly rates between similar to 7 and 13 Tg N yr(-1). These rates are in the range of previous modeling-based estimates but may represent a lower bound estimate due to the lack of data in this basin. Diazotroph variability among sub-basins may suggest endemicity but needs to be taken with caution due to biased sampling toward certain seasons and uneven spatial coverage. We provide recommendations for a more accurate representation of the IO in the global nitrogen budget and our knowledge of diazotroph biogeography. specialized OCEAN INDIEN 034 084 [Early access] [16 p.] 2023 https://www.documentation.ird.fr/hor/fdi:010090207 10.1002/lol2.10343 [F B010090207] https://www.documentation.ird.fr/hor/fdi:010090207 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2023-10/010090207.pdf IRD - Base Horizon / Pleins textes 2023-10-06 2025-02-24 fdi:010090207 fre