1. Evangelisches Schulzentrum Radebeul, Radebeul, Germany.
2. Christian-Albrechts-Universität zu Kiel, Kiel, Germany.
3. Helmholtz Centre Potsdam — GFZ German Research Centre for Geosciences, Potsdam, Germany. (corresponding author)
4. Helmholtz Centre Potsdam — GFZ German Research Centre for Geosciences, Potsdam, Germany.