During the past ten days we continued our transect along 60°E towards north, which we had started at the end of week 35. On August 31, we arrived at the southern slope of the Gakkel Ridge and conducted a Geotraces station, i.e. we ran a cast with the Large Rosette (see weekly report 2) and after that an Ultra-Clean Rosette cast. Then we continued the transect by alternating XCTD and Large Rosette casts and sometimes an additional Ultra-Clean Rosette cast. On two stations we also ran the In-situ pumps to determine the Thorium content of the water.

On September 1^st we reached the Karasik Mound where the water depth is only 600 m. There we made besides the Large Rosette cast also a multi-net cast as well as a LOKI (Light-frame Onsite Key species Investigation) cast to 1000 m. The multi-net was run down to the bottom as on all multi net casts, the LOKI was lowered only to 1000 m. At the end we also ran a large box core. We did not dare to use the multi-corer here, because we were afraid of damage due to too coarse sediment. For the following stations we sailed along the trench of the Gakkel Ridge from east to west. At the easternmost CTD station at 4850 m water depth we found a weak positive temperature anomaly at ca. 3500 m depth, indicative for the presence of a hydrothermal vent nearby. Therefore we decided to deploy a mooring here. The mooring contains a number of current meters, temperature, salinity and pressure meters, two sediment traps and an ice thickness meter. The instruments are located at 10 m und 200 m distance from the bottom, and in 3750 und 3400 m depth because of the temperature anomaly, and then distributed over the upper 750 m. The sediment traps are located in 230 m and in 4700 m depth. After the deployment we conducted a multi-corer cast in a distance of 1 nm. At the following station at 3500 m water depth another temperature anomaly was detected, this time centered at 2500 m. Therefore, we conducted also an Ultra-Clean Rosette cast at this position.