Surface water temperatures were normal in the whole investigated area. Salinity in the surface layer of the Eastern Gotland Basin was clearly below normal. Surface nutrient concentrations were normal for the season. Oxygen concentrations below 2 ml/l were present at depths exceeding 60-80 metres. Hydrogen sulphide was found deeper than 80 metres in the Western Gotland Basin and deeper than 125 metres in the Eastern Gotland Basin. Plankton activity was low.