Fragile archipelago

Due to its special nature- and cultural values, Archipelago Sea is a unique part of the Baltic Sea. It is also very vulnerable to changes.

An archipelago of ten thousand islands

You can find archipelago almost exclusively on the coast of Finland and Sweden. The Archipelago Sea is the largest archipelago area.  Because of the numerous islands the nature of the Archipelago Sea is rambling and it has plenty of coastline.

The Archipelago Sea area is very shallow with the middle depth in 23 meters. Near the coast, the sea depth is often less than 10 meters. On the other hand, in the deep basins, even 100 meters can be reached.

The salinity of the Archipelago Sea is only 0,6 per cent. That is so low rate that the water is stratified mainly according to temperature.

Flows bring water and alien substances

The flowing circumstances of the Baltic Sea make Archipelago Sea the flow-through area. Water flows from the actual Baltic Sea and the Gulf of Finland to the Bothnian Sea. The thresholds in the Archipelago Sea hinder the access of the nutrient rich water of the Baltic Sea to the Bothnian Sea. This mechanism called upwelling raises occasionally nutrient rich water up to the surface.

Water from the numerous rivers of the Archipelago Sea catchment is being carried through the archipelago to the open sea area. Along with the water are drifted also hazardous substances and nutrients which remain easily in the mazes of the archipelago.

Vulnerable to changes

Archipelago Sea is vulnerable to changes due to the shallowness, the weak water change and its brackish water environment. Big threats to its uniqueness are on the other hand human activity and the other the changing modes of function.

The archipelago is a challenging living area also for people. There are not many representatives of the peculiar archipelago culture left anymore. Permanent settlement has diminished into the fraction of the golden ages. Changes in the livelihood structures, among others, have accelerated the emigration. Permanent residences are more and more being replaced by the recreational settlement.

The landscape of the archipelago is zoned

Landscape of the Archipelago can be divided into three zones. The inner archipelago has land more than water and landscapes vary from the wooded island to the little rocky islets. Water areas are shallow and rambling. Gulfs, where the water changes poorly, are typical of the zone. The mainland is significant due to the fixed connection between mainland and archipelago.

The middle archipelago has the same amount of water and land. Fairly large, partly wooded islands are typical of the landscape. The middle archipelago is the heartland of habitation and the connection between islands and mainland is carried out by the ferries and boats.

In the outer archipelago landscape is dominated by the water. Rocks and islets dip out from the open sea nearly treeless. Area is very sparsely populated. 

More information
Outdoors.fi: Archipelago National Park

Region Åboland – Turunmaan seutu: The Archipelago Sea Biosphere Reserve