Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Poseidon	POS507	15.10.2016 - 01.11.2016		Baltic Sea Baltic Proper

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Arz Helge	Leibniz-Institut fur Ostseeforschung, Warnemunde	Warnemunde	Warnemunde

Ziel der Reise / Objectives of Cruise:

Objectives Based on the data and material collected mainly in and around the Landsort Deep and the Gotland Basin during the proposed cruise we aim to address following specific scientific questions: 1. What is the distribution/stratification of biomarkers in the water column and sediments of the Gotland Basin and Landsort Deep and how does this affect the proxy application in long sediment cores? 2. What is the importance of trace metal scavenging by redoxcline-derived MnOx particles and of Mn carbonate formation for sedimentary trace metal signatures of dynamic anoxic basins? 3. How did bottom currents affected sedimentation in the Landsort Deep during the Late Holocene and what was the paleoceanographic/paleoclimatologic relevance of these changes? 4. Are the transparent seismic units mass wasting deposits? What is the composition and the stratigraphic position of the suspected slide deposits? 5. Can the source area of the suspected debrites be recognized, what are the dimensions of the debritic material and what was the geological process of failure? Narrative On the 15th October noon, RV POSEIDON departed from Warnemunde for a 2 days long transit across the Baltic Sea to arrive the main working area in the central Baltic Sea on Monday morning the 17th Oktober. Main task in the eastern Gotland Basin was to collect surface sediments by means of a multicorer from two depth transects in the eastern part of the basin. During the first two days we concentrated on the southern transect, the third day we partly spent on the long-term monitoring station TF271 in the central part of the eastern Gotland Basin collecting CTD-rosette water samples for trace element studies and large volume water samples of 800 liters each from 4 water depths for filtration and organic biomarker studies, and completed our second northern multicorer transect. Generally, our 10 days working program in the Landsort Deep area consisted of nighttime multibeam and sediment acoustic profiling and daytime sediment coring by means of multicorer and gravity corer. During the first two days, we successfully recovered three long sediment cores and multicores at six stations before we had to interrupt our coring program for two days due to bad weather conditions. However, we used this time for an extensive mapping program in the southern and northeastern part of the basin, which will form a valuable source of information regarding the sedimentation pathways to the basin and the morphological constraints for the bottom currents entering the basin from the north. On 24 October, we resumed our coring work at three stations on a profile crossing a drift sediment body in the deep northern part of the basin. The next day, on Tuesday we used for water column work comparable to the main station in the first working area, with several CTD-rosette and Giant Water Sampler casts down to 430 m water depth. Wednesday and Thursday, we again worked on geological sampling stations in the central part of the basin interrupted by a nighttime sparker seismic reconnaissance. Unfortunately, this profiling ended earlier than expected due to an, on-board irreparable, failure of our equipment. Continuing with multicorer sampling, our station work was interrupted again on 28 October due to bad weather conditions, but was resumed later that day for further gravity coring. Saturday 29 October we used for two last coring stations in the southern part of the basin to return in the later afternoon to the central deep station completing the water column work with further CTD-rosette casts. After a last night of profiling and a multicorer station in the southern part of our working area, bad weather prohibited further planned work and we headed southward to reach the western Bornholm Basin for a biological sampling station on the 31 November. After a last short biological sampling station in the Arkona Basin, RV Poseidon arrived on the 1 November morning in Warnemunde, were the crui

Messungen / Measurements