Cruise report from R/V Aranda week 24-25, 2015

Type: Report
Author: Lars Andersson, Karin Wesslander


The water temperature in the surface layer was essentially normal for the season. Spring bloom was now over in the Skagerrak and Kattegat areas and nutrients showed low concentrations. Inorganic nitrogen was below the detection limit, while there were small amounts of phosphate left. In the Baltic Sea there was moderate plankton activity. Inorganic nitrogen was below detection limit while phosphate and silicate were higher than normal.

The effect of the inflow during December 2014 had now propagated to the northeast of the eastern Gotland Basin. The bottom water in the Bornholm Basin and Hanö Bight were still oxygenated but the concentration of oxygen was lower than at the previous measurement. In the western Gotland Basin the oxygen situation was still severe as acute hypoxia occurred from depths exceeding 60-70 meters and hydrogen sulphide from about 90 meters deep.