Japanese-Norwegian collaboration on the past environmental conditions of the Arctic Ocean within the framework of the IODP

During august 2004 IODP´s The Arctic Drilling Expedition 2004 (ACEX) drilled four closely spaced sites (M0001-M0004) on the 450 m thick acoustically stratified sediment sequence draping the crest of the Lomonosov Ridge between 87°N and 88°N. The main purp ose of the expedition was to retrieve a continuous record of the sediment package of the Lomonosov Ridge in order to elucidate the Cenozoic paleoceanographic history of the Arctic Ocean. Among the holes, 302-M0002A and 302-M0004A reached significant depth s; the others captured parts of the Quaternary. Micropaleontological studies give evidence for a nearly biologically dead Arctic Ocean during most of the last 40 million years ago. However, in stark contrast to this the Arctic Ocean was brewing with biosi liceous organisms in the Middle Eocene about 40-50 million years ago. The ultimate purpose of the project is a) to develop a diatom biostratigraphy for the middle Eocene of the Arctic and b) to assess the environmental conditions under which these organic rich sediments were deposited. However, since the retrieved diatom assemblages are so unique, the first step towards realizing the goals of the project is a detailed study on the taxonomy and evolution of the Middle Eocene diatoms. This work is assigned by ACEX to Japanese colleagues R. W. Jordan, M. Watanabe and I. Suto. The development of the diatom biostratigraphy is assigned to N. Koc. But, the development of the diatom biostratigraphy is heavily depended on the taxonomic work. Therefore, a very clos e collaboration with the Japanese colleagues is essential for the success of the project, which will result in several co-authored papers.