By Cicle_del_nitrogen_ca.svg: Johann Dréo (User:Nojhan), traduction de Joanjoc d'après Image:Cycle azote fr.svg. derivative work: Burkhard (Cicle_del_nitrogen_ca.svg) [CC BY-SA 2.0 fr (https://creativecommons.org/licenses/by-sa/2.0/fr/deed.en), CC BY-SA 2.5-2.0-1.0 (https://creativecommons.org/licenses/by-sa/2.5-2.0-1.0), CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons