Summary
During the expedition, which is part of the Swedish pelagic monitoring program, the Skagerrak, the Kattegat, the Sound and the Baltic Proper were visited.
The surface water temperature in the surveyed areas ranged between 16–18°C, and in the Eastern Gotland Basin, it was above normal, while in other areas, the surface water temperature was generally normal.
The concentrations of nutrients in the form of dissolved inorganic phosphorus (phosphate) and dissolved inorganic nitrogen in the surface water were above normal in the Eastern Gotland Basin. In other marine areas, the concentrations were generally normal for the season. For silicon in the form of silicate, concentrations in the Baltic Proper were normal at all stations. In the Skagerrak and the Kattegat, levels above normal for the season at most stations.
Acute oxygen deficiency, defined as oxygen levels below 2 ml/l, was observed from 60 meters in the Eastern Gotland Basin and from 70 meters in the Western Gotland Basin, Hanö Bay, and the Bornholm Basin. Also, in the Arkona Basin and the bottom waters of the Sound, oxygen levels below 2 ml/l were measured. Hydrogen sulphide was detected from a depth of 80 meters in both the Western and Eastern Gotland Basins. In several cases, the hydrogen sulphide levels were above normal.
The next scheduled expedition with the vessel Svea is planned to start the 19th of October in Lysekil.