Cruise report from R/V Aranda week 7, 2016
Author: Anna-Kerstin Thell
The expedition was part of the Swedish marine monitoring programme and covered the Skagerrak, the Kattegat, the Sound and the Baltic Proper. Mapping of winter nutrients were performed in the Baltic Proper. The temperature in the surface water was above normal in the Baltic Proper. The concentrations of nutrients were generally normal for the season in Skagerrak and Kattegat. In the Baltic Proper the concentration of phosphate was elevated in the whole area except for the western parts. The silicate was also elevated except in the south were it showed concentrations below normal. The effect of the inflow in December 2014 could not be detected further north than the station BY20 in the northern part of the Eastern Gotland Basin. At the station Gotland Deep BY15, oxygen was again present in the bottom water. In the Western and Northern Gotland Basins the oxygen situation remains very serious as anoxic conditions occurred at depths exceeding 70-100 meters. Hydrogen sulphide was observed at the sampling point in the Gulf of Gdansk which has not happened since 2008. The fluorescence measurement showed a beginning spring bloom in the center and the south of Skagerrak and the northern part of the Kattegat.