Summary
Very high surface phosphate concentrations were measured in the Baltic Proper. Silicate concentrations were also enhanced there, while levels of nitrogen compounds were normal. Nutrient concentrations in the Skagerrak-Kattegat area were normal or almost normal. The spring bloom in the Skagerrak-Kattegat area was just starting. In the Baltic Proper oxygen concentrations below 2 ml/l were found at depths exceeding 70 to 100 metres. Hydrogen sulphide was found in the bottom waters of the Gotland Deep(BY15), Landsort Deep (BY31)and Norrköping Deep(BY32).