SMHI performed an oxygen survey within SLU-Aqua’s cruise; the International Bottom Trawl Survey, that covers the Skagerrak and the Kattegat. SMHI joined the cruise to perform CTD measurements in connection to each trawl and to take water samples for the annual oxygen survey. Samples for nutrients and chlorophyll were also taken. Four of SMHIs standard stations; Släggö, Anholt E, Fladen and Å17 were visited during the cruise.
The oxygen situation in southern Kattegat was close to hypoxic. Oxygen concentrations near the limit of oxygen deficiency (< 2 ml/l) was found in the bottom water at most stations in the southern parts of the Kattegat. The concentrations ranged from 2.3 – 3.0 ml/l. Further north in Kattegat and in the Skagerrak the oxygen situation was good with bottom water concentrations above 4 ml/l. The only exception was the coastal station Släggö, in the outer part of the Gullmars fjord, were oxygen concentrations around 2.5 ml/l was found in the bottom water.