title: Response of the North Atlantic surface and intermediate ocean structure to climate warming of MIS 11.
abstract: Investigating past interglacial climates not only help to understand how the climate system operates in general, it also forms a vital basis for climate predictions. We reconstructed vertical stratification changes in temperature and salinity in the North Atlantic for a period some 400 ka ago (MIS11), an interglacial time analogue of a future climate. As inferred from a unique set of biogeochemical, geochemical, and faunal data, the internal upper ocean stratification across MIS 11 shows distinct depth-dependent dynamical changes related to vertical as well as lateral shifts in the upper Atlantic meridional circulation system. Importantly, transient cold events are recognized near the end of the long phase of postglacial warming at surface, subsurface, mid, and deeper water layers. These data demonstrate that MIS 11 coolings over the North Atlantic were initially triggered by freshwater input at the surface and expansion of cold polar waters into the Subpolar Gyre. The cooling signal was then transmitted downwards into mid-water depths. Since the cold events occurred after the main deglacial phase we suggest that their cause might be related to continuous melting of the Greenland ice sheet, a mechanism that might also be relevant for the present and upcoming climate.
authors.affiliation: Department of Marine Microbiology and Biogeochemistry, NIOZ Netherlands Institute for Sea Research, and Utrecht University, Den Burg, NL-1790 AB, the Netherlands.|Department of Paleoceanography, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, D-24148, Germany.
authors.forename: Evgenia S
authors.initials: ES
authors.lastname: Kandiano
authors.affiliation: Department of Marine Microbiology and Biogeochemistry, NIOZ Netherlands Institute for Sea Research, and Utrecht University, Den Burg, NL-1790 AB, the Netherlands.
authors.forename: Marcel T J
authors.initials: MT
authors.lastname: van der Meer
authors.affiliation: Department of Marine Microbiology and Biogeochemistry, NIOZ Netherlands Institute for Sea Research, and Utrecht University, Den Burg, NL-1790 AB, the Netherlands.|Faculty of Geosciences, Utrecht University, Utrecht, NL-3584 CD, the Netherlands.
authors.forename: Stefan
authors.initials: S
authors.lastname: Schouten
authors.affiliation: Department of Marine Geology, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, D-27568, Germany.
authors.forename: Kirsten
authors.initials: K
authors.lastname: Fahl
authors.affiliation: Department of Marine Microbiology and Biogeochemistry, NIOZ Netherlands Institute for Sea Research, and Utrecht University, Den Burg, NL-1790 AB, the Netherlands.|Faculty of Geosciences, Utrecht University, Utrecht, NL-3584 CD, the Netherlands.
authors.forename: Jaap S
authors.initials: JS
authors.lastname: Sinninghe Damsté
authors.affiliation: Department of Paleoceanography, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, D-24148, Germany.|Department of Marine Geology, Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, D-27568, Germany.
authors.forename: Henning A
authors.initials: HA
authors.lastname: Bauch