Continental and sea ice iron sources fertilize the Southern Ocean in synergy

• Published in: Geophysical Research Letters
• Main Authors: Person, Renaud, Vancoppenolle, M., Aumont, Olivier, Malsang, Manon
• Other Authors: Nucleus for European Modeling of the Ocean (NEMO R&D ), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Département des Géosciences - ENS Paris, Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL), ANR-16-CE01-0014,SOBUMS,Comprendre la réponse du cycle du carbone dans l'océan austral au stress climatique(2016)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: [SDE]Environmental Sciences; [SDU]Sciences of the Universe [physics]; Southern Ocean; Sea ice
• Online Access: https://hal.science/hal-03451384; https://hal.science/hal-03451384/document; https://hal.science/hal-03451384/file/Geophysical%20Research%20Letters%20-%202021%20-%20Person%20-%20Continental%20and%20Sea%20Ice%20Iron%20Sources%20Fertilize%20the%20Southern%20Ocean%20in%20Synergy.pdf; https://doi.org/10.1029/2021GL094761

International audience Iron release from melting continental and sea ice is deemed important for phytoplankton, the growth of which is iron-limited in the Southern Ocean. Both sources are generally considered separately, yet their effects on the biological carbon pump could interact. Using a global ocean-sea-ice-biogeochemical model with a representation of both continental and sea ice iron sources, we find them to have an overall additive effect on phytoplankton activity, increasing carbon export by +13.9% of the Southern Ocean total, with continental ice contributing +4.5% and sea ice +8.0%. The +1.4% residual is due to a coupled fertilization effect: When the iron source from continental ice is activated, iron in sea ice increases by 16%, so does iron transport toward low production areas. Overall, this increases phytoplankton activity: Fertilization is more efficient where sea ice melts than at locations of initial iron release by continental ice.