title: Source identification and distribution reveals the potential of the geochemical Antarctic sea ice proxy IPSO25.
abstract: The presence of a di-unsaturated highly branched isoprenoid (HBI) lipid biomarker (diene II) in Southern Ocean sediments has previously been proposed as a proxy measure of palaeo Antarctic sea ice. Here we show that a source of diene II is the sympagic diatom Berkeleya adeliensis Medlin. Furthermore, the propensity for B. adeliensis to flourish in platelet ice is reflected by an offshore downward gradient in diene II concentration in >100 surface sediments from Antarctic coastal and near-coastal environments. Since platelet ice formation is strongly associated with super-cooled freshwater inflow, we further hypothesize that sedimentary diene II provides a potentially sensitive proxy indicator of landfast sea ice influenced by meltwater discharge from nearby glaciers and ice shelves, and re-examination of some previous diene II downcore records supports this hypothesis. The term IPSO25-Ice Proxy for the Southern Ocean with 25 carbon atoms-is proposed as a proxy name for diene II.
authors: School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, PL4 8AA UK.
authors: S T
authors: ST
authors: Belt
authors: School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, PL4 8AA UK.
authors: L
authors: L
authors: Smik
authors: School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, PL4 8AA UK.
authors: T A
authors: TA
authors: Brown
authors: Department of Marine Science and Convergence Technology, Hanyang University ERICA Campus, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan-si, Gyeonggi-do 426-791, South Korea.
authors: J-H
authors: JH
authors: Kim
authors: School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, PL4 8AA UK.
authors: S J
authors: SJ
authors: Rowland
authors: British Antarctic Survey, High Cross, Madingley Road, Cambridge CB3 0ET, UK.
authors: C S
authors: CS
authors: Allen
authors: Department of Marine Science and Convergence Technology, Hanyang University ERICA Campus, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan-si, Gyeonggi-do 426-791, South Korea.
authors: J-K
authors: JK
authors: Gal
authors: Department of Marine Science and Convergence Technology, Hanyang University ERICA Campus, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan-si, Gyeonggi-do 426-791, South Korea.
authors: K-H
authors: KH
authors: Shin
authors: Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, South Korea.
authors: J I
authors: JI
authors: Lee
authors: Isoprime Limited, Isoprime House, Earl Road, Cheadle Hulme, Stockport SK8 6PT, UK.
authors: K W R
authors: KW
authors: Taylor