Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Heincke	HE449	01.08.2015 - 22.08.2015		Greenland Sea

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Mau Susan	Universitat Bremen, Zentrum fur Marine Umweltwissenschaften	Trondheim	Troms?

Ziel der Reise / Objectives of Cruise:

Short cruise report R/V HEINCKE HE449 The intention of the cruise was to investigate methane production and removal processes in the water column and sediments off Svalbard. We studied the spatial distribution of dissolved methane in the water column and measure the activity of methane oxidizing microorganisms in the water column and surface sediments. Especially the microbial methane oxidation, controlling the emission of methane from the ocean to the atmosphere was of interest for us as only a small number of water column studies exist that quantify the actual methane oxidation rate especially in high latitude regions. The target areas were the fjords and shelf regions off Svalbard. We investigated Storfjorden, Van Mijenfjorden, Isfjorden and the connected Billefjorden. On the shelf we focused on the area between Hornsund and Van Mijenfjorden and the area between Van Mijenfjorden and Isfjorden. The cruise left Trondheim (Norway) on the 1st of August and arrived to Svalbard after three days of transit. As Strofjorden, our first target area, was closed by drift ice, we collected water samples along a transect crossing the fjord's mouth to the South. Also our next target area, the fjord of Hornsund, was closed by ice and thus work was conducted on the shelf in front of Hornsund. As our results of the Southern Storfjorden area were interesting, we went back for further sampling at this location. Ice conditions had still not changed to allow an entrance into the fjord and only additional sampling along the southern transect could be implemented. On the 10th of August we returned to Hornsund and after additional sampling in this area, we moved northward to the Bellsund area, Van Mijenfjorden, and finally into Isfjorden and Billefjorden, where water and sediment sampling work was finished on the 18th of August. Water and surface sediments were collected with a CTD-water sampler, in situ pumps, an under-water mass spectrometer (UWMS), and a multi-corer (MUC). Acoustic surveys were conducted during the night and the ADCP was recording current velocity and direction during most of the cruise. We mainly sampled the water column along transects crossing the fjords and shelf regions. At locations of observed gas flares and in front of and after the sills of the fjords, in situ pumps and the MUC were deployed in addition to CTD-water sampler. We conducted 39 hydrocasts along 8 transects and the UWMS was successfully towed at different depths in areas of flare clusters. In situ pumps were deployed at 8 stations in three or four different water depths above flares, but also in front of and behind the sills of the different fjords. This was done to identify differences in microbial communities in the water masses inside the fjords compared to those outside the fjords. The grab sampler was mainly used to identify if the sediments were suitable for deployment of the MUC. The grab sampler was used at 5 stations and the MUC was deployed at 10 stations. First results during the cruise revealed frequent presence of flares. Most surface sediments did not contain elevated methane concentrations except the sediments at one flare site, but methane concentrations in the water column were generally above oceanic background levels of 2-3 nM. The UWMS data correlated well with the flare detection and the methane concentration analyses of water samples. Methane oxidation rates were usually higher near the seafloor than in the surface waters. Apart from the weather issues that did not allow sampling in some areas, it was a very successful cruise and will provide a detailed picture of the methane sources and sinks off Svalbard after further biogeochemical analyses of the samples on shore.

Messungen / Measurements