Stockholm Archipelago

The Stockholm Archipelago is the largest archipelago in Sweden, and the second-largest archipelago in the Baltic Sea . Part of the archipelago has been designated as a Ramsar site since 1989.
The water has a pH value of 7.0 or slightly lower, to be compared with approximately 8.0 for seawater. Together with humic substances this sometimes causes a bit brownish water colour, especially in the inner parts. The salinity varies between freshwater and brackish water with poor salinity. In the outer parts of the archipelago, the salinity reaches around 0.6–0.7 per cent by weight, to be compared with at least 1.5 for beginning to taste salty and around 3.0 or more for proper oceanic water. Sea ice is regularly formed in the inner parts every winter.

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