Attachment 96707Thanks! Some additional photos of my favorite islands.
Baltic sea is composed on several "pools" and there are several processes that affect it's very sensitive eco-system, such as agricultural emissions.
Most powerful is the sporadic but sparce Atlantic salt pulse through the straits between Denmark and Sweden, which brings oxygen to Baltic sea. The salinity changes as you go closer to headwaters from 1.5 % to almost 0 % where the rivers are bringing fresh water into the sea. Very good for swimming in the summer. However, most areas around Finland get frozen in winter.