Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Polarstern	PS115-2	05.09.2018 - 16.10.2018		Arctic Ocean Greenland Sea Norwegian Sea Barents Sea

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Stein Rudiger	Alfred-Wegener-Institut fur Polar- und Meeresforschung	Longyearbyen	Bremerhaven

Ziel der Reise / Objectives of Cruise:

Expedition PS115/2 was mainly related to geoscientific investigations in the area of the southern Lomonosov Ridge and the Amundsen Basin towards the Laptev Sea continental margin. The overall goal of the research program was the detailed reconstruction of the short- and long-term climate history as well as the tectonic evolution of the Arctic Ocean. Although we had to steam back towards Longyearbyen due to a serious case of medical emergency and thus lost about six days of research time, we could reach all our main research goals at the very end. This was mainly possible for two reasons. First, we could use the Northern Sea Route through the Russian EEZ twice, i.e., during the transit towards the main study area as well as for the way back. Dominantly ice-free conditions allowed a much more precise expedition's planning and also saved time. Second and not less important, was the excellent cooparation between crew and scientists during the entire expedition. Key activities of the expedition can be summarized as follows: ? During transit and within the main working areas, Parasound was running continuously between 14.09. and 04.10.. About 3900 km new Hydrosweep profiles were obtained and detailed high-quality bathymetry surveys were carried out in selected areas of the Lomonosov Ridge and the Amundsen Basin. In the Amundsen Basin an unknown "Seamount" elevating about 600 m above the abyssal plain, was recovered. ? In total, 1160 km of high-quality seismic profiles were recorded, part of which are multichannel seismic lines with the 3000 m long streamer. These data are important to optimize the locations of potential drill site we have proposed for a future IODP drilling campaign in the Lomonosov Ridge area. Basin on our new seismic data, the newly recovered "Seamount" in the Amundsen Basin has most probably a magmatic origin. ? A detailed geological coring program (5 x Kastenlot corer, 31 x Gravity corer, 20 x Giant box corer, 10 x Multicorer, 2 x Dredge) was carried out on Lomonosov Ridge and in the Amundsen Basin. The coring of undisturbed near-surface sediment sections from potential IODP drill sites is an important supplement to the long deep sedimentary sections hopefully to be drilled during a future IODP drilling compaign. Furthermore, the recovered high-quality sediment cores will certainly allow detailed reconstructions of the Quaternary climate history. The rocks dredged from the "Seamount" unfortunately did not contain any magmatic/basaltic material. However, they are composed of sand-, silt- and claystones, partly covered by manganese crusts. These rocks are probably more or less directly overlying the oceanic basement and thus may allow to get some information about the age of the basement as well as some insight into the "old" (early Cenozoic?) climate and environmental history of the preglacial warm & ice-free Arctic Ocean. ? The geoscientific program was supplemented by additional activities related to sea ice studies (i.e., ice observations during helicopter flights, measurements of sea ice thickness, ice coring and the deployment of 17 drift buoys) and meteorological studies (i.e., the launching of 90 radiosondes attached to a weather balloon as part of the special observing period of the Year Of Polar Prediction – YOPP, and measurements of the cloud base height using a cloud camera system). ? As major part of Expedition PS115/2, a "Floating University" was held onboard Polarstern under the umbrella of the International Research Training Group "Processes and impacts of climate change in the North Atlantic Ocean and the Canadian Arctic - ArcTrain". Within this program, 13 Canadian and German PhD and master students with very different scientific backgrounds (i.e., geosciences, sea ice, glaciers, oceanography, remote sensing, and modelling) were introduced to all technical aspects of field work in marine sciences as well as to the concepts of teamwork, interdisciplinary and international collabo

Messungen / Measurements