Summary
In Skagerrak and Kattegat the spring bloom was over and the amount of nutrients was low, which is normal for the season. In the Baltic Proper winter conditions prevailed. The concentrations of nitrite+nitrate were normal while the amount of phosphate still were elevated at all stations and much over normal in the southwest parts. Silicate was also elevated in these areas. The inflow that occurred in November/December 2011 had reached the southeast parts of the Baltic Proper and had started to enter the eastern Gotland Basin. Hydrogen sulphide was found in the western and eastern Gotland basin from depth exceeding 95-100. Oxygen concentrations below 2 ml/l (hypoxia) were found from depth exceeding 80-85 meters in the eastern Gotland Basin, from 70-85 meters in the western Gotland Basin and the southeast Baltic Proper. In Hanö Bight hypoxia was found at depths exceeding 65 meters.