Distinctive $^{13}$C isotopic signature distinguishes a novel sea ice biomarker in Arctic sediments and sediment traps

• Published in: Marine Chemistry
• Main Authors: Belt, Simon, Massé, Guillaume, Vare, Lindsay, Rowland, Steven, Poulin, Michel, Sicre, Marie-Alexandrine, Sampei, Makoto, Fortier, Louis
• Other Authors: School of Geography, Earth and Environmental Sciences Plymouth (SoGEES), Plymouth University, Canadian Museum of Nature (CANADA), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), 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-Saclay-Centre National de la Recherche Scientifique (CNRS), Paléocéanographie (PALEOCEAN), 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-Saclay-Centre National de la Recherche Scientifique (CNRS)-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-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Laval Québec (ULaval)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2008
• Subjects: Arctic; Isotopes; Biomarker; IP$_{25}$; δ$^{13}$C; Sea ice; Sediment; [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
• Online Access: https://hal.science/hal-03192517; https://hal.science/hal-03192517/document; https://hal.science/hal-03192517/file/Arctic%20HBI%20isotopes%20SB%20revised.pdf; https://doi.org/10.1016/j.marchem.2008.09.002

International audience A C$_{25}$ highly branched isoprenoid (HBI) monoene hydrocarbon, designated IP$_{25}$, has been proposed previously to originate from diatoms living in Arctic sea ice, while the presence of IP25 in sediments has been suggested to be a proxy for the occurrence of former Arctic sea ice. Here, we show that the $^{13}$C isotopic composition of IP$_{25}$ in sea ice, in sediment trap material collected under sea ice, and in high latitude northern sediments, is distinctive (isotopically ‘heavy’) and distinguishable from that of organic matter of planktonic or terrigenous origin. Mean δ$^{13}$C values for IP$_{25}$ were − 22.3 ± 0.4‰ (sea ice), − 19.6 ± 1.1‰ (sediment traps) and − 19.3 ± 2.3‰ (sediments). These measurements, therefore, support further the proposed use of IP$_{25}$ as an Arctic sea ice proxy.