Baltic Sea

Baltic Sea, enclosed sea, northern Europe, bounded by Sweden, Finland, Estonia, Latvia, Lithuania, Russia, Poland, and Germany. It is connected with the North Sea by a series of winding channels: Øresund, Storebælt, Lillebælt, Kattegat, and Skagerrak. From the peninsula of Jutland, Denmark, considered the Baltic's limit, the sea extends east to longitude 30° east and north to about latitude 66° north. The greatest length of the Baltic, from Lübeck, Germany, to Haparanda, Sweden, is about 1,500 km (930 mi); the breadth varies from 685 km (425 mi), between Stockholm and St Petersburg, to less than 80 km (50 mi) at the southern extremity. The Baltic covers an area of about 414,400 sq km (160,000 sq mi).

The northern extension consists of two large gulfs: the Gulf of Bothnia, between Finland and Sweden, and the Gulf of Finland, between Finland and Estonia. The Gulf of Riga is a prominent feature of the Baltic's Estonian and Latvian coasts. On the coasts of Poland and Germany are smaller indentations, including the Gulf of Gdańsk and the Bay of Szczecin (Stettin), both in Poland, and the German bays of Lübeck and Kiel. The principal islands are the following: Rügen Island (Germany), Bornholm Island and the Danish groups (Denmark), Gotland and Öland islands (Sweden), Saaremaa (Ösel) and Hiiumaa (Dägo) islands (Estonia), and the Ahvenanmaa (Åland) Islands (Finland).

The Baltic receives the drainage from a large part of northern Europe, including Estonia, Latvia, Lithuania, northern Germany, and nearly all of Sweden. As a result of this drainage and of the restricted channel to the North Sea, the surface water of the Baltic contains relatively little salt—only a third as much salt as the Atlantic Ocean—and the salinity shows a tendency to decrease towards the west and north. Surface currents of low salinity flow constantly from the Baltic to the North Sea, while deeper currents, with a larger salt content, flow in the opposite direction. Tidal action is apparent only in the southern part of the Baltic.

Storms are frequent in the Baltic Sea and often cause severe damage to ships. On September 28, 1994, as many as 1,000 people were drowned when the ferry Estonia sank in a gale off the Finnish coast. Easterly winds are particularly dangerous because they create huge tidal waves. Navigation in the northern part of the Baltic is suspended during the winter and early spring because of ice.

The Baltic is of great commercial importance to northern Europe. The most important ports are Copenhagen in Denmark; Kiel and Lübeck in Germany; Szczecin, Gdańsk, and Gdynia in Poland; Kaliningrad, St Petersburg, and Kronshtadt in Russia; Riga in Latvia; Tallinn in Estonia; Helsinki and Turku in Finland; and Stockholm, Karlskrona, and Malmö in Sweden. The Baltic is connected with the North Sea by the Nord-Ostsee Kanal (the Kiel or Kaiser Wilhelm Canal), with the White Sea by the White Sea-Baltic Canal, and with the Volga by the Volga-Baltic Waterway. The Baltic is connected with the Caspian and Black seas by the Volga-Baltic waterway and the Volga-Don Canal.