Physical and biogeochemical properties in landfast sea ice (Barrow, Alaska): Insights on brine and gas dynamics across seasons

• Published in: Journal of Geophysical Research: Oceans
• Main Authors: Zhou, Jiayun, Delille, Bruno, Eicken, Hajo, Vancoppenolle, Martin, Brabant, Frédéric, Carnat, Gauthier, Geilfus, Nicolas-Xavier, Papakyriakou, Tim, Heinesch, Bernard, Tison, Jean-Louis
• Other Authors: Laboratoire de Glaciologie Bruxelles, Université libre de Bruxelles (ULB), Interfacultary Center for Marine Research (MARE), Université de Liège, Geophysical Institute Fairbanks, University of Alaska Fairbanks (UAF), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-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)-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-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)-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), University of Manitoba Winnipeg, Gembloux Agro-Bio Tech Gembloux
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: isotope; Ra; brine; barrow; sea ice; nutrient; chlorophyll-a; argon; [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]; [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph]; Barrow; Sea ice; Alaska
• Online Access: https://hal.science/hal-00912618; https://hal.science/hal-00912618/document; https://hal.science/hal-00912618/file/jgrc.20232.pdf; https://doi.org/10.1002/JGRC.20232

International audience The impacts of the seasonal evolution of sea-ice physical properties on ice-ocean biogeochemical exchanges were investigated in landfast ice at Barrow (Alaska) from January through June 2009. Three stages of brine dynamics across the annual cycle have been identified based on brine salinity, brine volume fraction, and porous medium Rayleigh number (Ra). These are sea-ice bottom-layer convection, full-depth convection, and brine stratification. We further discuss the impact of brine dynamics on biogeochemical compounds in sea ice: stable isotopes of water (δD, δ 18 O), nutrients (NO 3 - , PO 4 3- , NH 4 + ), microalgae (chlorophyll-a), and inert gas (argon). In general, full-depth convection events favor exchanges between sea ice and seawater, while brine stratification limits these exchanges. However, argon responds differently to brine dynamics than the other biogeochemical compounds analyzed in this study. This contrast is attributed to the impact of bubble nucleation on inert gas transport compared to the other biogeochemical compounds. We present a scenario for argon bubble formation and evolution in sea ice and suggest that a brine volume fraction approaching 7.5-10% is required for inert gas bubbles to escape from sea ice to the atmosphere.