A Mid-European Decadal Isotope-Climate Record from 15,500 to 5000 Years B.P.

Science, Vol. 284, No. 5420, p. 1654-1657, 1999 

U. von Grafenstein, J. Jouzel
Laboratoire des Sciences du Climat et de l'Environnement (LSCE), F-91198 Gif-sur-Yvette, France.
H. Erlenkeuser
Leibniz-Labor für Altersbestimmung und Isotopenforschung der Universität Kiel, Germany.
A. Brauer
Laboratoire de Botanuque Historique et Palynologie, Faculty des Sciences et Techniques de Saint-Jerome, Marseille, France, and GeoForschungsZentrum Potsdam, Germany.
S.J. Johnsen
Departement of Geophysics, The Niels Bohr Institute of Astronomy, Physics and Geophysics, University of Copenhagen.

Oxygen-isotope ratios of precipitation (d18OP) inferred from deep-lake ostracods from the Ammersee (southern Germany) provide a climate record with decadal resolution. The record in detail shows many of the rapid climate shifts seen in central Greenland ice cores between 15,000 and 5000 years before the present (B.P.). Negative excursions in the estimated d18OP from both of these records likely reflect short weakenings of the thermohaline circulation caused by episodic discharges of continental freshwater into the North Atlantic. Deviating millennial-scale trends, however, indicate that climate gradients between Europe and Greenland changed systematically, reflecting a gradual rearrangement of North Atlantic circulation during deglaciation.