Nutrient concentrations were normal in the whole investigated area, with the exception of phosphate that showed elevated levels in the southern part of the Baltic Proper. The water below the halocline in the Arkona Basin was well oxygenated with levels of ca. 5 ml/l. In the rest of the Baltic Proper oxygen concentrations below 2 ml/l were observed at depths exceeding 70 to 80 meters. Hydrogen sulphide was found, in the Western Gotland Basin, deeper than 80-90 meters. In the Eastern Gotland Basin hydrogen sulphide began at depths between 125 and 150 meters. A plankton bloom was ongoing in the Baltic Proper as well as in intermediate layers in Skagerrak, while it was almost over in the Kattegat.