Glacial reduction and millennial-scale variations in Drake Passage throughflow
| Type | Article | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| Date | 2015-11 | ||||||||
| Language | English | ||||||||
| Author(s) | Lamy Frank1, Arz Helge W.2, Kilianc Rolf3, 4, Lange Carina B.5, 6, Lembke-Jene Lester1, Wengler Marc1, Kaiser Jerome2, Baeza-Urrea Oscar3, Hall Ian R.7, Harada Naomi8, Tiedemann Ralf1 | ||||||||
| Affiliation(s) | 1 : Helmholtz Zentrum Polar & Meeresforsch, Alfred Wegener Inst, Marine Geol Sect, D-27570 Bremerhaven, Germany. 2 : Leibniz Inst Balt Sea Res, Dept Marine Geol, D-18119 Rostock, Germany. 3 : Univ Trier, Geol Fachbereich Raum & Umweltwissensch, D-54286 Trier, Germany. 4 : Univ Magallanes, Inst Patagonia, Punta Arenas 6200000, Chile. 5 : Univ Concepcion, Dept Oceanog, Concepcion 4030000, Chile. 6 : Univ Concepcion, COPAS Sur Austral Program, Ctr Oceanog Res Eastern South Pacific COPAS, Concepcion 4030000, Chile. 7 : Cardiff Univ, Sch Earth & Ocean Sci, Cardiff CF10 3AT, S Glam, Wales. 8 : Japan Agcy Marine Earth Sci & Technol, Res & Dev Ctr Global Change, Yokosuka, Kanagawa 2370061, Japan. |
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| Source | Proceedings Of The National Academy Of Sciences Of The United States Of America (0027-8424) (Natl Acad Sciences), 2015-11 , Vol. 112 , N. 44 , P. 13496-13501 | ||||||||
| DOI | 10.1073/pnas.1509203112 | ||||||||
| WOS© Times Cited | 69 | ||||||||
| Keyword(s) | paleoceanography, Drake Passage, Antarctic Circumpolar Current, glacial-interglacial changes, sedimentology | ||||||||
| Abstract | The Drake Passage (DP) is the major geographic constriction for the Antarctic Circumpolar Current (ACC) and exerts a strong control on the exchange of physical, chemical, and biological properties between the Atlantic, Pacific, and Indian Ocean basins. Resolving changes in the flow of circumpolar water masses through this gateway is, therefore, crucial for advancing our understanding of the Southern Ocean's role in global ocean and climate variability. Here, we reconstruct changes in DP throughflow dynamics over the past 65,000 y based on grain size and geochemical properties of sediment records from the southernmost continental margin of South America. Combined with published sediment records from the Scotia Sea, we argue for a considerable total reduction of DP transport and reveal an up to similar to 40% decrease in flow speed along the northernmost ACC pathway entering the DP during glacial times. Superimposed on this long-term decrease are high-amplitude, millennial-scale variations, which parallel Southern Ocean and Antarctic temperature patterns. The glacial intervals of strong weakening of the ACC entering the DP imply an enhanced export of northern ACC surface and intermediate waters into the South Pacific Gyre and reduced Pacific-Atlantic exchange through the DP ("cold water route"). We conclude that changes in DP throughflow play a critical role for the global meridional overturning circulation and interbasin exchange in the Southern Ocean, most likely regulated by variations in the westerly wind field and changes in Antarctic sea ice extent. | ||||||||
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