Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Maria S. Merian	MSM85	23.07.2019 - 13.08.2019	GROCE	Greenland Sea

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Mertens Christian	Institut fur Umweltphysik der Universitat Bremen	St. John`s	Longyearbyen

Ziel der Reise / Objectives of Cruise:

During the cruise MSM 85 water samples were collected for helium and neon isotope analysis along hydrographic sections across the shelf of East Greenland and across the East Greenland Current. Helium and neon are uniquely suited as tracers of glacial meltwater in the ocean. Parallel sampling of transient tracers (CFCs, SF6) provide an estimate of the ventilation time and an integral melting rate when combined with the melt water fractions. This distribution of melt water is of more than local interest. The additional freshwater in the key regions of the formation of North Atlantic Deep Water could alter the vertical density stratification, modify the amount of deep water formed, and have consequences for the strength of the climate relevant Atlantic meridional overturning circulation. This cruise is part of the BMBF program GROCE (Greenland Ice Sheet – Ocean Interaction, www.groce.de). The objective of the trace chemistry group was to determine how the ratio of different nutrients affect the community structure. In the context of the changing Arctic, freshening of the East-Greenland shelf region is expected in the coming decades which may increase organic carbon and Fe supply, but decrease summertime NO3 supply due to enhanced stratification. A key research question is therefore how such shifts in the ratios of nutrient availability will affect primary producers. This was addressed by the deployment of a towfish to collect samples for organic carbon species, community structure, nutrient concentrations and micronutrient concentrations. In addition to the underway sample collection, a number of incubation experiments were performed to test the biological response to different combinations of nutrient spikes. Underway measurements of dissolved N2O and CO in seawater were carried out with the goals to: Decipher the water column distribution of N2O and CH4, infer their main formation mechanisms, and investigate the air-sea dynamics of N2O, CH4 and CO. Maria S. Merian left the port of St. John's, Canada on July 23. After a transit of 3.5 days, the ship arrived at the first CTD station in the Irminger Sea on July 27. On the following two days 18 CTD stations were made along a section toward the center of the Irminger Sea. The section was completed on July 29. The second CTD section started after a transit of 176 nm on July 29. It went back to the Greenland coast and 19 CTD stations were made until July 31. The transit along the coast to the third CTD section was 236 nm and took until August 1. The following section went across Denmark Strait, 23 CTD stations where made along the track. The forth section started after a transit of 142 nm on August 3. This section again crossed the Denmark Strait, now toward Greenland. It was completed on August 4, after 24 CTD casts. On the transit to the next section three CTD stations where made across the entrance of Scoresby Sound. In the afternoon of August 4 Maria S. Merian reached the marginal ice zone and the speed needed to be reduced to proceed safely through the ice flows, also the tow fish needed to be recovered. The ship arrived at the first station of section five, that was located close to the coast at a depth of 80 m, on August 4. The section was terminated after 24 CTD casts and after a short transit the next section was started on August 6. This new section had 24 CTD casts and went back to the Greenland coast. It was finished on August 8. After a transit along the coast, section six started on August 8. 19 CTD casts where made along this section which was completed on August 10. The transit to the last section at 77? 30' N took 14 hours, and the ship arrived at the first CTD station of this section on August 11. The most western station on this section was reached at about 5? 2.4' W at a water depth of about 1150 m. From there on four more CTD stations were made in east direction before the work program ended on August 12. On August 13 Maria S. Merian ar

Messungen / Measurements