100 Places To Remember: The Archipelago Sea, Finland
Geschreven op 13-3-2010 - Erik van Erne. Geplaatst in Natuur
A Sea that is More Like a Labyrinth. Navigating the labyrinth of the Archipelago Sea off the coast of Finland in the Baltic Sea is a hazardous business due to its varying depths and abundant rocks. The archipelago consists of roughly 40,000 islands if you count every rock that breaks the surface, but only 257 of them measure more than one square kilometre and even fewer are inhabited.
Emerging after the last ice age about 10,000 years ago, the islands are still in a post-glacial rebound process, rising 4-10 mm a year. The old islands are growing and newer small ones constantly emerge from the shallow water, where the mean depth is only 23 metres.
The sea freezes over during cold winters, making it possible to drive on the ice, and official ice roads are laid out to connect the islands.
For centuries, fish has been a vital source of food for the islanders; even when the crops failed, seafood was always available. Despite the growth of tourism, fishing is still the primary source of income in the region, which is particularly famous for its Baltic herring and rainbow trout.
The Archipelago Sea is exposed to what is known as eutrophication. This is where nutrient pollution from sewage effluent or the run-off from fertilisers stimulates algal bloom in shallow, brackish waters like the Archipelago Sea. Besides making the water cloudy, the algal bloom causes a lack of oxygen and reduces the amount of food, affecting the health of fish species like salmon, trout and Baltic herring.
Global climate change and the associated rising temperatures, decreasing ice cover and increasing winter rainfall, are expected to exacerbate eutrophication, with potentially damaging consequences for biodiversity, tourism and fishing in the Archipelago Sea.
