Surface water temperatures as well as surface salinities were at normal levels for the season in the whole investigated area. Surface nutrient concentrations were normal in most areas, with the exception of silicate that showed levels below normal in the main part of the Baltic Proper. The oxygen conditions in the bottom water of the Arkona Basin were very variable while concentrations between 0.9 and 3.4 ml/l. Elsewhere in the Baltic Proper, oxygen concentrations below 2 ml/l were found at depths exceeding 50-70 metres. Hydrogen sulphide was found in the Eastern- and Western Gotland Basins.