Summary
The early spring bloom has finished in the Skagerrak and Kattegat. Surface nutrient concentrations were still low. The spring bloom had not really started in the Baltic Proper and nutrient concentrations were normal, with the exception of phosphate which was high, particularly in the southern Baltic. An algal bloom was observed in the Kalmar Sound. Surface water temperature was normal in the whole area. Below the halocline in the Arkona Basin, the water was well oxygenated with levels of ca. 8 ml/l. In the remainder of the Baltic Proper, oxygen concentrations below 2 ml/l were observed at depths exceeding 80 to 100 metres. Hydrogen sulphide was found deeper than 100-150 metres in the Western Gotland Basin while in the eastern Gotland Basin hydrogen sulphide began at depths between 125 and 150 metres.