1. Geosciences, Department of Climatology, University of Trier, D-54286 Trier, Germany
2. Geophysical Institute, University of Alaska Fairbanks, Fairbanks, Alaska 99775–7320, U.S.A.
3. Formerly at: Alfred-Wegener-Institute for Polar and Marine Research, D-27515 Bremerhaven, Germany
4. Institute of Marine Research at the University of Kiel, D-24105 Kiel, Germany