Ruud Streefkerk

We are looking out over the Baltic Sea in Poland, a sea-arm of the North Atlantic Ocean. The word Baltic was probably derived from the Latin word for band or belt: balteus, and related to the Danish word 'Baelt' for strait.This large and brackish inland sea was formed by glacial erosion during the last ice age and has a lower salinity than the Atlantic Ocean, due to the barrier of the Kattegat in Denmark and the influx of more than 200 rivers. Because of its location and lower salinity, the Baltic Sea is usually frozen for about 45% in the winter, dependent on the temperatures. The freezing starts around mid November in the northern tip of the Gulf of Bothnia, where the ice gets up to 70cm thick, and reaches the open waters of the Baltic Sea near Stockholm at the end of December.