Walter Menapace, University of Bremen, MARUM – Center for Marine Environmental Sciences, Bremen, Germany, Deborah Tangunan, University of Bremen, Department of Geosciences, Bremen, Germany, Michael Maas, Universität Bremen, Advanced Ceramics - MAPEX Centre of Materials and Processes, Bremen, Germany, Trevor Williams, Texas A&M University, College Station, NY, United States and Achim Kopf, MARUM - University of Bremen, Bremen, Germany