In May 2010 the German Federal Institute for Geosciences and Natural Resources (BGR) accomplished its third exploration cruise to the German license area in the Pacific Nodule Belt. High resolution bathymetry and acoustic backscatter mapping of the two subareas of the license area centered at 12°N/118°W and 12.5°N/138°W has been completed during two previous cruises in 2008 and 2009. The aim of the third cruise was the eastern part of the German license area where we carried out seafloor video observations and a comprehensive sampling program. Measurements of pore water oxygen concentration document an average oxygen penetration depth of 1.5 to 2 m. The manganese nodules are mainly of oxic diagenetic origin. Nodule abundances predominantly range between 10 and 30 kg m-2 wet weight and change frequently within tens to hundreds of meters. In general, the nodule abundance in terms of mass per area unit is controlled by the size of the nodules rather than by their number. Areas of medium to high nodule abundance are dominated by large nodules and show high acoustic backscatter values whereas low backscatter values coincide with areas dominated by smaller nodules and slightly lower nodule abundances.
In July 2006 the Bundesanstalt für Geowissenschaften und Rohstoffe (Federal Institute for Geosciences and Natural Resources, hereafter called BGR) concluded a contract with the International Seabed Authority (ISA) on a license area for the exploration of deep-sea ferromanganese nodules in the tropical northeast Pacific Ocean between the Clarion and Clipperton fracture zones. This license area covers 75,000 km2 and is separated in two parts, "W1" (17,000 km2) and "E1" (58,000 km2) (Fig. 1, Tab. 1). In October/November 2008 and 2009 the BGR carried out two exploration cruises with R/V KILO MOANA, a research research vessel based at the University of Hawaii in Honolulu.