Highly branched isoprenoids as proxies for variable sea ice conditions in the Southern Ocean

• Published in: Antarctic Science
• Main Authors: Massé, Guillaume, Belt, Simon T., Crosta, Xavier, Schmidt, Sabine, Snape, Ian, Thomas, David N., Rowland, Steven J.
• Other Authors: 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), Biogeochemistry Research Centre (BGC), Plymouth University, UMR 5805 Environnements et Paléoenvironnements Océaniques et Continentaux (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), School of Ocean Sciences Menai Bridge, Bangor University
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: diatoms; polyunsaturates; 13 C isotopes; IP 25; HBI; Adélie Land; [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; Arctic; East Antarctica; Southern Ocean; Antarc*; Antarctic Science; Antarctica; Phytoplankton; Sea ice
• Online Access: https://hal.science/hal-02105653; https://doi.org/10.1017/S0954102011000381

International audience Concentrations of a highly branched isoprenoid (HBI) diene determined in over 200 sediment samples from the Arctic co-vary with those of an HBI monoene (IP 25) shown previously to be a sedimentary sea ice proxy for the Arctic. The same diene, but not monoene IP 25 , occurred in nine sea ice samples collected from various locations around Antarctica. The diene has been reported previously in Antarctic sea ice diatoms and the 13 C isotopic compositions of the diene determined in two Antarctic sea ice samples were also consistent with an origin from sea ice diatoms (d 13 C-5.7 to-8.5%). In contrast, HBIs found in two Antarctic phytoplankton samples did not include the diene but comprised a number of tri-to pentaenes. In sediment samples collected near Adélie Land, East Antarctica, both the diene and the tri-to pentaenes often co-occurred. 13 C isotopic compositions of the tri-to pentaenes in three sediment samples ranged from-35 to-42% whereas that of the diene in a sediment sample was-18%. We propose the presence of this isotopically 13 C enriched HBI diene in Antarctic sediments to be a useful proxy indicator for contributions of organic matter derived from sea ice diatoms. A ratio of the concentrations of diene/ trienes might reflect the relative contributions of sea ice to phytoplanktonic inputs of organic matter to Antarctic sediments.