Details

Autor(en) / Beteiligte

• Max, Lars
• Nürnberg, Dirk
• Chiessi, Cristiano M.
• Lenz, Marlene M.
• Mulitza, Stefan

Titel

Subsurface ocean warming preceded Heinrich Events

Ist Teil von

• Nature communications, 2022-07, Vol.13 (1), p.4217-4217, Article 4217

Ort / Verlag

London: Nature Publishing Group UK

Erscheinungsjahr

2022

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• Although the global environmental impact of Laurentide Ice-Sheet destabilizations on glacial climate during Heinrich Events is well-documented, the mechanism driving these ice-sheet instabilities remains elusive. Here we report foraminifera-based subsurface (~150 m water depth) ocean temperature and salinity reconstructions from a sediment core collected in the western subpolar North Atlantic, showing a consistent pattern of rapid subsurface ocean warming preceding the transition into each Heinrich Event identified in the same core of the last 27,000 years. These results provide the first solid evidence for the massive accumulation of ocean heat near the critical depth to trigger melting of marine-terminating portions of the Laurentide Ice Sheet around Labrador Sea followed by Heinrich Events. The repeated build-up of a subsurface heat reservoir in the subpolar Atlantic closely corresponds to times of weakened Atlantic Meridional Overturning Circulation, indicating a precursor role of ocean circulation changes for initiating abrupt ice-sheet instabilities during Heinrich Events. We infer that a weaker ocean circulation in future may result in accelerated interior-ocean warming of the subpolar Atlantic, which could be critical for the stability of modern, marine-terminating Arctic glaciers and the freshwater budget of the North Atlantic. The mechanism driving past Laurentide Ice-Sheet instabilities remains elusive Here, the authors present a sediment record from the subpolar western North Atlantic and show that massive warming of the upper interior ocean was the likely trigger for repeated collapses of the Laurentide Ice-Sheet and iceberg discharge into the North Atlantic, known as Heinrich Events.