The seasonal cycle of δ 13 C DIC in the North Atlantic subpolar gyre

• Published in: Biogeosciences
• Main Authors: Racapé, Virginie, Metzl, Nicolas, Pierre, Catherine, Reverdin, Gilles, Quay, P. D., Ólafsdóttir, Sólveig R.
• Other Authors: Biogéochimie-Traceurs-Paléoclimat (BTP), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), 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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), 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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Équipe CO2 (E-CO2), Interactions et Processus au sein de la couche de Surface Océanique (IPSO), School of Oceanography Seattle, University of Washington Seattle, Marine Research Institute (MARINE RESEARCH INSTITUTE), Marine Research Institute
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2014
• Subjects: [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; [SDE.MCG]Environmental Sciences/Global Changes; North Atlantic
• Online Access: https://hal.archives-ouvertes.fr/hal-00991675; https://hal.archives-ouvertes.fr/hal-00991675/document; https://hal.archives-ouvertes.fr/hal-00991675/file/bg-11-1683-2014.pdf; https://doi.org/10.5194/BG-11-1683-2014

International audience This study introduces for the first time the δ 13 C DIC seasonality in the North Atlantic subpolar gyre (NASPG) using δ 13 C DIC data obtained in 2005-2006 and 2010-2012 with dissolved inorganic carbon (DIC) and nutrient observations. On the seasonal scale, the NASPG is characterized by higher δ 13 C DIC values during summer than during winter, with a seasonal amplitude between 0.70 ± 0.10‰ (August 2010-March 2011) and 0.77 ± 0.07‰ (2005-2006). This is mainly attributed to photosynthetic activity in summer and to a deep remineralization process during winter convection, sometimes influenced by ocean dynamics and carbonate pumps. There is also a strong and negative linear relationship between δ 13 C DIC and DIC during all seasons. Winter data also showed a large decrease in δ 13 C DIC associated with an increase in DIC between 2006 and 2011-2012, but the observed time rates (-0.04‰ yr -1 and +1.7 μmol kg -1 yr -1 ) are much larger than the expected anthropogenic signal.