ARK-XXV/3, Weekly Report No. 6

Reykjavik – Bremerhaven, 6 September – 12 September 2010

During this week the onboard operations were focused on seismic work in Kane Basin. Before RV POLARSTERN headed north, all ocean bottom seismometers (OBS) had to be retrieved which were deployed along the second, 400 km long N-S trending refraction seismic line. With moderate seas, all instruments have been recovered by the crew very quickly and experienced. A first quality control demonstrated that the noise created by the simultaneous operations of the seismic vessel RV BERGEN SURVEYOUR in the nearby Melville Bay caused only minor interferences which are of less influence on our data than earlier expected. All operations along the second refraction seismic line are successfully completed. During OBS retrievement, sediment cores were extracted by the gravity corer at 11 selected locations along the line. The sampling material will be used for geochemical and microbiological analysis. The subsequently derived geochemical parameters will support modelling evolution processes of sedimentary basins. This modelling will be accompanied by microbiological investigations of the hydrocarbon degradation by microorganisms in the North Baffin Bay. These investigations were only sparsely done before in the Arctic coastal seas and there is not much known about microbial hydrocarbon degradation activities and communities under these special polar conditions.  The extracted core material is to be processed in the onboard laboratories and prepared for subsequent analysis at home.

In the second half of the week R/V POLARSTERN headed north doing reflection seismics along a line parallel to the Canadian maritime boundary. After 2 weeks of fine weather a meteorological low caused strong northerly winds and rough seas with 4 m waves. The sea calmed down when the vessel reached the Smith Sound. According to weather forecasting and ice reports the expected conditions were sufficiently good to conduct reflection seismic operations in the Kane Basin.  It was planned to acquire for the first time ever MCS data along two profiles in this area to better analyse transform faults and sediment structures between Baffin Bay and Lincoln Sea and to extend the recent database of this underexplored area. Ice coverage was 3/10 to 5/10 in Kane Basin and because of the numerous icebergs a shortened streamer with 60 channels was used for the seismic operation. At September 10th in the evening RV POLARSTERN reached 80°09’N the northernmost position of this cruise leg. After the completion of reflection seismic work in Kane Basin and geological sampling of selected coastal parts, RV POLARSTERN headed south. Starting on Sunday morning MCS operations in the Smith Sound are being continued using a 3900 m seismic streamer. The acquired data will fill up a still existing gap between data recorded during a previous expedition to the Nares Strait in 2001 and the recent survey area in Baffin Bay.

All colleagues are in good health and send greetings home

Volkmar Damm
September 12th, 2010, Smith Sound,  -5°C