Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Polarstern	PS117	15.12.2018 - 07.02.2019	HAFOS	Weddell Sea South Atlantic Ocean

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Boebel Olaf	Alfred-Wegener-Institut fur Polar- und Meeresforschung	Cape Town	Punta Arenas

Ziel der Reise / Objectives of Cruise:

The expedition PS117 to the Antarctic took Polarstern from Cape Town, South Africa, via the German Neumayer Station III, Antarctica, to the Weddell Sea and on to Punta Arenas, Chile. The expedition comprised logistic and scientific undertakings. Polarstern expedition PS117 sought to provide contributions to scientific projects encompassing physical oceanography, marine biology and meteorology, with the general aim to improve our understanding of the evolution of the Weddell Sea water masses and the ecological and chemical cycles of the Weddell Sea. Specific scientific projects conducted throughout the expedition comprised: (1) HAFOS (Hybrid Antarctic Float Observing System), investigated the circulation and evolution of Warm Deep Water and Weddell Sea Bottom Water by means of oceanographic deep-sea moorings, hydrographic sections and autonomous floats (some as part of SOCCOM). Biological aspects of HAFOS concern the acoustic ecology of the Weddell Sea and its fauna, for which moorings were equipped with autonomous recorders. (2) FePhyrus investigated the sources and sinks of trace metals and isotopes in the Weddell Sea and Lazarev Sea and the interaction between iron and the microbial food web. (3) SIPES 2 (Sea Ice Production and Ecology Study) investigated the ecological importance of sea ice for the pelagic food web and carbon supply to top predators (birds and mammals). (4) ALGENOM-2 investigated the molecular evolutionary and ecological dynamics of unicellular eukaryotic assemblages and of selected taxa thereof. (5) CombiBac aimed for a better understanding of bacterial remineralization processes in the Weddell Sea with emphasis on their dependence on water temperature and substrate concentration. (6) SOCCOM observing and modelling the biogeochemical cycles of the Southern Ocean as a means of improving climate modelling; observations are made by having deployed biogeochemical profiling floats (BGC- Argo) that are being distributed throughout the Southern Ocean. UK PICCOLO scientists study

Messungen / Measurements

Verankerungen / Moorings