Modelling the impact of biogenic particle flux intensity and composition on sedimentary Pa/Th

• Published in: Quaternary Science Reviews
• Main Authors: Missiaen, Lise, Menviel, Laurie C., Meissner, Katrin J., Roche, Didier M., Dutay, Jean-Claude, Bouttes, Nathaëlle, Lhardy, Fanny, Quiquet, Aurélien, Pichat, Sylvain, Waelbroeck, Claire
• Other Authors: Climate Change Research Centre, ARC Centre of Excellence for Climate System Science, University of New South Wales, Sydney 2052, Australia, University of New South Wales Sydney (UNSW), Mark Wainwright Analytical Centre Sydney (UNSW ), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Modélisation du climat (CLIM), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Institut Louis Bachelier, Université Claude Bernard Lyon 1 (UCBL), Université de Lyon, Max Planck Institute for Chemistry (MPIC), Max-Planck-Gesellschaft, Processus et interactions de fine échelle océanique (PROTEO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), 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)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-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)-École polytechnique (X)-Centre National d'Études Spatiales Toulouse (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-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)-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 de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Australian Research Council, ARC: FT180100606, DP180100048, KJM, LCM and LM acknowledge funding from the Australian Research Council grant DP180100048 awarded to KJM and LCM and grant FT180100606 awarded to LCM., European Project: 339108,EC:FP7:ERC,ERC-2013-ADG,ACCLIMATE(2014)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: Pa/Th; Abrupt climate events; Particle fluxes; Ocean circulation; iLOVECLIM; envir; socio; NADW; North Atlantic Deep Water; North Atlantic; Northwest Atlantic
• Online Access: https://doi.org/10.1016/j.quascirev.2020.106394; https://hal.archives-ouvertes.fr/hal-02883163

International audience There is compelling evidence that millennial climate variability of the last glacial period was associated with significant changes in the Atlantic Meridional Overturning Circulation (AMOC). Several North Atlantic sedimentary Pa/Th records indicate a consistent and large Pa/Th increase across millennial-scale events, which has been interpreted as considerable reduction in North Atlantic Deep Water (NADW) formation. However, the use of sedimentary Pa/Th as a pure kinematic circulation proxy is challenging because Pa and Th are also highly sensitive to changes in particulate flux intensity and composition that might have occurred across these millennial scale events. In this study, we use the Pa/Th enabled iLOVECLIM Earth System Model of intermediate complexity to evaluate the impact of changes in biogenic particle flux intensity and composition on the Atlantic Pa/Th. We find that in our model, changes in Particulate Organic Carbon (POC), and to a lesser extent biogenic opal production, can significantly affect the sedimentary Pa/Th, possibly explaining up to 30% of the observed North Atlantic Pa/Th increase across Heinrich stadial 1. The sedimentary Pa/Th response is also likely sensitive to shifts in the geographical distribution of the particles, especially in high scavenging regions. Our study suggests that a decrease in opal production in the northwest Atlantic can induce a far field Pa/Th increase in a large part of the North Atlantic basin. Therefore, local monitoring of particle fluxes may not be sufficient to rule out any influence of changing particle fluxes on sedimentary Pa/Th records.