This report describes some basic aspects of the hydrographical conditions in the open sea areas around Sweden, based on SMHls environmental monitoring program during 1993. A new monitoring program has been implemented, consisting of two types different types of stations. First, frequent stations which are few but have a high sampling frequency making it possible to resolve annual variations. Secondly mapping stations visited only a few times per year as to asses, oxygen conditions in the Kattegat and the Baltic deep waters and the pool of nutrients during the pre bloom season.

The most interesting event during 1993 was the large inflow of salt water to the Baltic that occured in the beginning of the year. As a result the deep water in the East Gotland Basin was renewed and oxygenated for the first time since 1978.