Southern Ocean frontal structure and sea-ice formation rates revealed by elephant seals

• Published in: Proceedings of the National Academy of Sciences
• Main Authors: Charrassin, Jean-Benoît, Hindell, Mark A., Rintoul, Stephen R., Roquet, Fabien, Sokolov, S., Biuw, Martin, Costa, Daniel P., Boehme, Lars, Lovell, Phill, Coleman, R., Timmermann, Ralph, Meijers, Andrew S., Meredith, Michael P., Park, Young-Hyang, Bailleul, Frédéric, Goebel, Michael, Tremblay, Yann, Bost, Charles-André, Mcmahon, Clive R., Field, Iain C., Fedak, Michael A., Guinet, Christophe
• Other Authors: 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), Antarctic Wildlife Research Unit, University of Tasmania Hobart, Australia (UTAS), Commonwealth Scientific and Industrial Research Organisation (CSIRO) (CSIRO), Commonwealth Scientific and Industrial Research Organisation (CSIRO), Sea Mammal Research Unit University of St Andrews (SMRU), Natural Environment Research Council (NERC)-School of Biology University of St Andrews, University of St Andrews Scotland -University of St Andrews Scotland, Center for Ocean Health, University of California, Center for Marine Science, Department of Bentho-pelagic processes, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Centre d'études biologiques de Chizé (CEBC), Centre National de la Recherche Scientifique (CNRS), Antarctic Ecosystem Research Division, Southwest Fisheries Science Center (SWFSC), NOAA National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA)-National Oceanic and Atmospheric Administration (NOAA)-NOAA National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA)-National Oceanic and Atmospheric Administration (NOAA), Department of Ecology and Evolutionary Biology, University of California Santa Cruz (UCSC), University of California-University of California, Departement of Ecology and Evolutionary Biology, Long Marine Laboratory, School for Environmental Research, Charles Darwin University
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2008
• Subjects: instrumentation; Antarctic Circumpolar Current; ocean observation; marine predators; sea-ice modeling; geo; envir; Antarctic; Southern Ocean; Antarc*; Elephant Seals; Mirounga leonina; Sea ice; Southern Elephant Seals
• Online Access: https://doi.org/10.1073/pnas.0800790105; https://hal.archives-ouvertes.fr/hal-00319824

International audience Polar regions are particularly sensitive to climate change, with the potential for significant feedbacks between ocean circulation, sea ice, and the ocean carbon cycle. However, the difficulty in obtaining in situ data means that our ability to detect and interpret change is very limited, especially in the Southern Ocean, where the ocean beneath the sea ice remains almost entirely unobserved and the rate of sea-ice formation is poorly known. Here, we show that southern elephant seals (Mirounga leonina) equipped with oceanographic sensors can measure ocean structure and water mass changes in regions and seasons rarely observed with traditional oceanographic platforms. In particular, seals provided a 30-fold increase in hydrographic profiles from the sea-ice zone, allowing the major fronts to be mapped south of 60°S and sea-ice formation rates to be inferred from changes in upper ocean salinity. Sea-ice production rates peaked in early winter (April–May) during the rapid northward expansion of the pack ice and declined by a factor of 2 to 3 between May and August, in agreement with a threedimensional coupled ocean–sea-ice model. By measuring the highlatitude ocean during winter, elephant seals fill a ‘‘blind spot'' in our sampling coverage, enabling the establishment of a truly global ocean-observing system.