Diatom delta C-13, delta N-15, and C/N since the Last Glacial Maximum in the Southern Ocean: Potential impact of Species Composition

• Published in: Paleoceanography
• Main Authors: Jacot Des Combes, Hélène, Esper, Oliver, De La Rocha, Christina, Abelmann, Andrea, Gersonde, Rainer, Yam, Ruth, Shemesh, Aldo
• Other Authors: Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Department of Environmental Sciences and Energy Research Rehovot, Weizmann Institute of Science Rehovot, Israël, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Bentho-pelagic processes, This work was supported by GIF grant G-649-154.8/ 1999, EPICA-MIS (contract 3868) within the 6th EU Framework Programme, and the DFG Research Center, Ocean Margins., European Project: 39423,FP6-SUSTDEV,EPICA-MIS
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2008
• Subjects: [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Indian; Pacific; Scotia Sea; Southern Ocean; Antarc*; Antarctica
• Online Access: https://hal.univ-brest.fr/hal-00467138; https://hal.univ-brest.fr/hal-00467138/document; https://hal.univ-brest.fr/hal-00467138/file/Jacot_Des_Combes_08.pdf; https://doi.org/10.1029/2008PA001589

International audience Measurements of delta C-13, delta N-15, and C/N on diatom-bound organic matter were made over the Holocene and Last Glacial Maximum (LGM) from three sediment cores in the Southern Ocean, one each from the Atlantic, Indian, and Pacific sectors. The site in the Scotia Sea (Atlantic sector) differed considerably from the other two sites by having markedly lower delta C-13, more variable delta N-15 and C/N ratios, and a sedimentary diatom assemblage that was never dominated by Fragilariopsis kerguelensis. Although environmental parameters certainly have a strong impact on the isotope ratios, delta C-13 is also correlated to the proportion of F. kerguelensis in the three cores investigated here (r(2) = 0.8). Extreme values of delta C-13, delta N-15, and C/N at the Last Glacial Maximum were also related to the abundance of winter stages of Eucampia antarctica. These results suggest that diatom specific isotope records should be interpreted in conjunction with information on the species composition of the samples.