1. Faculty of Environment and Natural Resources Albert‐Ludwigs‐University Freiburg Germany
2. Alfred Wegener Institute Helmholtz Center for Polar and Marine Research Potsdam Germany
3. Now at Institute of Arctic and Alpine Research University of Colorado Boulder Boulder CO USA
4. Helmholtz‐Zentrum Potsdam Deutsches GeoForschungsZentrum GFZ Potsdam Germany