Cruise report from R/V Svea week 45, 2022

Type: Report
Author: Karin Wesslander


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 above normal and varied between 10 and 12 degrees in all visited areas. At several stations in the Skagerrak and Kattegat, the temperature was above normal throughout the water column and in the Baltic Proper it was warmer than normal down to the halocline. The surface salinity was normal and varied between 34 psu in Skagerrak to 7 psu in the Baltic Proper.

The nutrient concentration in the surface water had not increased as much as it usually does between October and November and were lower than normal at several areas. The concentration of DIN and DIP was below normal in the outer regions of Skagerrak and the Western and Northern Gotland Basin. The silicate concentrations were below normal in the Western Gotland Basin. Higher levels than normal were observed in the Gotland Basins below 100 metres.

The oxygen condition in the Skagerrak and the Kattegat was good, the oxygen levels had increased in the Kattegat bottom water since October. In the Arkona Basin lower oxygen concentrations than in October were observed near the bottom, they were below normal around 2 ml/l. No hydrogen sulphide was observed in the Hanö Bight or the Bornholm Basin. 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.