Cruise report from R/V Svea week 37-38, 2022

Type: Report
Author: Örjan Bäck


The Skagerrak, the Kattegat, The Sound and the Baltic Proper was visited during this cruise, which

is part of the national marine monitoring programme of Sweden.

The temperature in the surface water was normal and varied between 15 and 17 degrees Celsius in all visited areas. The surface salinity was lower than normal at the outermost stations in the Skagerrak and somewhat higher than normal in the Sound and in the Eastern Gotland Basin.

The halocline in the Kattegat was shallower than normal and the salinity below the halocline was somewhat higher than the monthly mean. At station BY38, between Öland and Gotland, the stratification was instead deeper than normal and the oxygen did not reach zero until at around 85 metres depth.

The nutrient concentration was overall at normal levels for the season. In the surface water in the Western Gotland Basin somewhat elevated concentrations of dissolved inorganic nitrogen (DIN) were measured, probably because of earlier occasions of upwelling;

Higher than normal concentrations of DIN were also encountered in the Gotland Basins below 100 metres depth, also at the bottom in the Bornholm Basin.

The oxygen condition in the Skagerrak and the Kattegat was good, values higher than normal was measured at the bottom in the Kattegat. In the Arkona Basin oxygen concentrations higher than normal were also present closest to the bottom, in the rest of the Baltic Proper the oxygen condition is very poor, with hydrogen sulphide concentrations closest to the bottom at, or close to, record high values.