Summary
Surface temperatures were higher than normal in the Skagerrak and the Kattegat. Nutrient concentrations in the surface layer were normal for the season with exception of higher phosphate and silicate level in the southern Kattegat In the northern Kattegat (Fladen) bottom water oxygen concentration was 4.4 ml/l and in the Arkona Basin (BY1) 3.6 ml/l. Oxygen concentrations in the Baltic Proper were below 2 ml/l everywhere at depths exceeding 60-80 metres. Hydrogen sulphide was found below 100 metres in the eastern- and from 80-90 metres in the western Gotland Basins. Surface accumulations of cyanobacteria (blue green algae) were observed in the Baltic.