Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Alkor	AL592	15.04.2023 - 27.04.2023	WINTER COD 2021-25 DAM-SUSTAINMARE DAM SPACEPARTI	Arkona Basin Mecklenburg Bight ICES-Subarea 22 (also ICES-subarea IIIc) Baltic Sea Kiel Bight ICES-Subarea 25 (part of ICES-subarea IIId) Bornholm Basin

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Dierking Jan	Helmholtz Centre for Ocean Research Kiel (GEOMAR)	Kiel	Kiel

Ziel der Reise / Objectives of Cruise:

This multidisciplinary cruise extended a 37-year long-term data series on ecosystem composition and functioning of the pelagic systems of the Baltic Sea. A key characteristic of the cruise was the integration of oceanographic and biological information to enhance the causal understanding of changes in the structure and function of food webs and the population structure and biological characteristics of fish stocks, as well as evolutionary processes in this system. The resulting data and sample sets support ongoing projects in the Research Unit Marine Evolutionary Ecology at GEOMAR and national and international collaborations, including the "Winter cod 2021-2025" cruise series in the DAM project SpaCeParti. The spatial focus of AL592 lay on the central (Bornholm Basin, ICES subdivision ("SD") 25) and western (Kiel and Mecklenburg Bight, SD22) Baltic Sea, but also included stations along the cruise transect to cover the salinity gradient across the cruise area. Specific investigations included a detailed hydrographic survey (oxygen, salinity, temperature) and plankton sampling (zoo- and ichthyplankton including gelatinous plankton, to determine community composition, species abundances and distributions, and to take samples for dietary tracer, nutritional condition and genetic analyses) on standardized station grids in SD22 and SD25, and fishery hauls with a scientific bottom trawl in both areas. The latter served to determine stock structure, gonadal maturation and liver parasite infestation of cod, and to sample tissue and otolith samples for individual-level genetic and ecological analyses. The abundance and distribution of fishes in the cruise area was also assessed with hydroacoustic methods. Additional cruise components were the vertically resolved phytoplankton and zooplankton sampling for studies of plankton phenology, and copepod and water sampling along the salinity gradient for for research lines on local adaption and microbial (eukaryotes, bacteria, archaea) diversity and ecology.

Messungen / Measurements