South Kvarken (Finnish: Ahvenanrauma, Swedish: Södra Kvarken) is the narrowest stretch of sea between Finnish Åland and Sweden, forming a strait connecting the Sea of Åland and the Bothnian Sea of approximately 30 km (18.5 mi) across.
South Kvarken (Finnish: Ahvenanrauma, Swedish: Södra Kvarken) is the narrowest stretch of sea between Finnish Åland and Sweden, forming a strait connecting the Sea of Åland and the Bothnian Sea of approximately 30 km (18.5 mi) across.
The Bothnian Bay or Bay of Bothnia (Swedish: Bottenviken; Finnish: Perämeri) is the northernmost part of the Gulf of Bothnia, which is in turn the northern part of the Baltic Sea. The land holding the bay is still rising after the weight of ice-age glaciers has been removed, and within 2,000 years the bay will be a large freshwater lake since its link to the south Kvarken is mostly less than 20 metres (66 ft) deep. The bay today is fed by several large rivers, and is relatively unaffected by tides, so has low salinity. It freezes over each year for up to six months. Compared to other parts of the Baltic, it has little plant or animal life.
Kvarken (Swedish: Kvarken, Norra Kvarken (as opposed to South Kvarken); Finnish: Merenkurkku, lit. 'throat of the sea') is the narrow region of the Gulf of Bothnia separating the Bothnian Bay (the inner part of the gulf) from the Bothnian Sea. The distance from the Swedish mainland to the Finnish mainland is around 80 km (50 mi), while the distance between the outermost islands is only 25 km (16 mi). The water depth in the Kvarken region is only around 25 metres (82 ft). The region also has an unusual rate of land rising at almost 10 mm (0.39 inches) a year.
Several attempts to cross the strait swimming have been made, but cold water and currents have usually been insurmountable obstacles. The first successful crossing was carried out by Lennart Flygare, Pavio Grzelewski and Tore Klingberg, who on 24 July, 2018, swam from Valassaaret (Valsörarna) on the Finnish side to Holmöarna in Sweden. It took them 12 hours 2 minutes to cross the strait.
The Åland Sea (or the Sea of Åland; Swedish: Ålands hav, Finnish: Ahvenanmeri) is a waterway in the southern Gulf of Bothnia, between Åland and Sweden. It connects the Bothnian Sea with the Baltic Sea proper. The western part of the basin is in Swedish territorial waters while the eastern part is in Finnish territorial waters.
The Åland Sea has two sub-basins. The main basin is the Åland Sea proper, also called the northern Åland Sea basin. In the south, there is the smaller Lågskär Deep, also called the Lågskär Basin or the southern Åland Sea basin. The narrowest part on the northern edge of the basin is named the Southern Quark or South Kvarken (Swedish: Södra Kvarken, Finnish: Ahvenanrauma). The trench running on the bottom of the Sea of Åland contains the second-deepest spot of the Baltic Sea, at a depth of 301 meters, which is second only to Landsort Deep. The mean depth of Åland Sea is 75 m, area 5,477 km and its volume is 411 km. The Archipelago Sea and the Åland Sea regulate water exchange between Gulf of Bothnia and Baltic Proper.