History of Atlantic water advection to the Arctic Ocean : a review of 20 years of progress since the “Oden”–“Polarstern” expedition ARCTIC 91

• Main Author: Spielhagen, Robert F.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Deutsche Gesellschaft für Polarforschung; Alfred-Wegener-Institu für Polar- und Meeresforschung 2012
• Subjects: Arctic; Arctic Ocean; Fram Strait; Global warming; Ice Sheet; North Atlantic; Polarforschung; Sea ice
• Online Access: https://oceanrep.geomar.de/id/eprint/19713/; https://oceanrep.geomar.de/id/eprint/19713/1/2012_Spielhagen_Polarforschung82-1_19-36.pdf; http://epic.awi.de/31714/1/Polarforschung_82-1_19-36.pdf

The variability of Atlantic Water advection to the Arctic Ocean is described for the last about 50 million years based on available published sources. Until the opening of the Fram Strait as a deep-water passage at about 17 million years before present the inflow of Atlantic Water may have occurred through gaps in morphologic barriers, but results from microfossil findings are in part contradictory and difficult to interpret. After the opening, brownish deep-sea Arctic sediments reflect well-oxygenated deep-sea conditions and an improved exchange with the North Atlantic. The build-up of first ice sheets on northern Eurasian continental and shelf areas in the Late Tertiary may have resulted in intensive brine formation at the ice sheet margins and a significantly weaker influence of Atlantic Water on the Arctic intermediate waters. The history of Quarternary glacial-interglacial variability in the central Arctic is not well understood for most of the last 2 million years due to the lack of carbonate microfossils. For the last 200,000 years, however, short intervals of intensive Atlantic Water advection during interglacials and interstadials can be clearly identified in a number of sediment cores. Seasonally open water conditions (i.e., reduced sea ice) during these periods and even during maximum glaciation at Arctic continental margins probably made additional moisture available for the (re)growth of adjacent ice sheets. After the last deglaciation, Atlantic Water quickly returned to the Arctic and established conditions close to the modern ones. High-resolution records from the Fram Strait, however, indicate a rapid temperature rise of the Atlantic Water layer during the last 100 years, which most probably reflects on-going global warming and the so-called “Arctic Amplification“.