Application of modern analog technique to marine Antarctic diatoms: Reconstruction of maximum sea-ice extent at the Last Glacial Maximum

• Published in: Paleoceanography
• Main Authors: Crosta, Xavier, Pichon, Jean-Jacques, Lloyd, Burckle
• Other Authors: Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (EPOC), Lamont-Doherty Earth Observatory (LDEO), Columbia University New York
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 1998
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Antarctic; Southern Ocean; Antarc*; Sea ice
• Online Access: https://hal.science/hal-02105716; https://hal.science/hal-02105716/document; https://hal.science/hal-02105716/file/Crosta_Paleocean1998.pdf; https://doi.org/10.1029/98PA00339

International audience Modern analog technique (MAT) applied to Antarctic diatoms is a new approach for quantitative sea‐ice paleoreconstructions in the Southern Ocean. In a first step we show that MAT is a better approach than the Imbrie and Kipp Method to reconstruct the modern sea‐ice pattern. We then use this approach to reconstruct sea‐ice presence in number of months per year during the last glacial maximum (LGM). At this time, sea‐ice presence was greater than today, leading to a shorter diatom growing season. The maximum sea‐ice extent, inferred from quantitative values of sea‐ice presence, was located 5–8° north of its actual position, leading to double the surface of modern winter sea ice. This greater sea‐ice extent may have played a significant role on atmospheric and surface oceanic circulations and therefore on southern mid‐latitude and high‐latitude climates. It may also have reduced the amount of heat, moisture, and CO2 from the ocean to the atmosphere, thus participating in the lowering of atmospheric CO2 during the LGM