The research program and the aims of the cruise mirror the plans of both involved projects (DECADE & SMIS) and are depicted in the working plan of the expedition: By means of hydrographic work the physical and biogeochemical conditions in the upper 2000 m of the water column in the catchment area of Kiel276 will be registered. Those CTD registrations are used to locate the Azores Front relative to the position of the deep sea mooring Kiel 276 along three meridians (23°W, 22°W and 21°W) between

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... 0°N and 37°N allowing for a 3-D mapping of the front. The mooring Kiel276-29 will be recovered following the emergency warning send by the subsurface buoy prior to the cruise. Additionally, extensive tests of the SMIS fleet composed of surface vehicle and bottom unit will be carried out. The work is completed by trials of several AUV components and test of acoustic systems in various configurations. Narrative of the cruise with technical details (J. Waniek, IOW) 12.05.2015-In the morning the cruise participants embark the ship and after uploading the containers started setting up the laboratories and testing the gear. 13.05.2015 -At 12:00 UTC after safety instruction Poseidon left the port of Malaga and started the transit to our working area at 35°N, 21°W. Our estimated arrival time in the working area is the 17th May. 14.05-16.05.2015-Transit to our working area under relatively good weather and sea conditions 17.05.-18.05.2015-Hydrographic work along the 21°W meridian and some trials of the SMIS components. 19.05.2015-We started the day work at 8:00 UTC with the attempt to release the broken mooring (May 2013, Kiel276-29a). Unfortunately, there was no response from the release units and no instruments surfaced until lunch time. We have started searching the area for buoyancy spheres at surface, but without success. At mid day the decision was made to abandon the position and continue with the hydrographic work over night. 20.05.2015-Today at 8:00 UTC the replacement mooring Kiel276-29b deployed in September 2013 was release and surfaced 1 hour later. We have collected the instruments and realized that the surface buoy and 1500 m lines, several buoyancy spheres and 2 current meters are missing. The remaining recovered instruments e.g. 4 current meters, inclinometer and both sediment traps worked over the entire deployment period. After finishing the recovery of the Kiel276-29 we continued our trials with the bottom-unit, later to be used as underwater fuel station for the SMIS fleet. 21.05-27.05.2015-The seven days were used for hydrographic work by means of CTD along 21°W, 22°W, and 23°W with additional test of SMIS components. Most of the CTD casts were done over full depth and samples taken for a variety of parameters. 28.05.2015-Over most of the cruise, the sea conditions did not allow deployment of the AUV, but today day before the cruise finishes the sea was relatively calm and the swell reasonable (less than 1.5 m). Therefore the AUV was deployed and dived to approximately 1000 m depth. The AUV mission was successful and we collected additional data allowing for additional optimization of the system on land.