School of Geography, Earth and Environmental Sciences, University of Plymouth, Plymouth, PL4 8AA UK.
Department of Marine Science and Convergence Technology, Hanyang University ERICA Campus, 55 Hanyangdaehak-ro, Sangnok-gu, Ansan-si, Gyeonggi-do 426-791, South Korea.
Nat Commun. 2016 Aug 30;7:12655. doi: 10.1038/ncomms12655.
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.
先前有研究提出，南大洋沉积物中二不饱和高度支化异戊二烯（HBI）脂质生物标志物（双烯 II）的存在可作为古南极大西洋海冰的替代指标。本研究表明，双烯 II 的一个来源是共生的硅藻柏雷克西亚属（Berkeleya adeliensis）。此外，柏雷克西亚属在板状冰中大量繁殖，这反映在 >100 个来自南极沿海和近岸环境的表层沉积物中双烯 II 浓度的离岸向下梯度上。由于板状冰的形成与过冷淡水的流入密切相关，我们进一步假设沉积物中的双烯 II 提供了一个潜在敏感的替代指标，可以指示受附近冰川和冰架融水排放影响的固定海冰，对一些先前的双烯 II 岩芯记录的重新检验支持了这一假设。我们提出了 IPSO25-Ice Proxy（南大洋 25 个碳原子的替代指标）这一术语，作为双烯 II 的替代指标名称。
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