] The island of Saaremaa separates the Gulf of Riga, located between Estonia and Latvia, from the rest of the Baltic Sea.
After the Gulf of Bothnia and the Gulf of Finland, the Gulf of Riga is the third largest gulf in the Baltic Sea. Even though it is positioned right alongside the main basin of the Baltic Sea, it is protected by islands, and therefor slightly isolated from the rest of the Baltic Sea. Water salinity varies inside the area: in the estuaries of the large Pärnu and Daugava rivers that flow into the Gulf of Riga, water is almost fresh, whereas closer to the Baltic Sea proper, it is more salty. The great rivers also make the water murkier, and at its deepest, vegetation in the Gulf of Riga extends down to 11 metres.
The Gulf of Riga is shallow and rich in fish stocks. Due to its isolation, the area suffers to a larger extent than the open coastal areas from the consequences of eutrophication, which include as algae blooms. The John Nurminen Foundation’s projects have improved the efficiency of wastewater treatment in Riga, and in other smaller cities of the Baltic states. A new project called BEST is also being prepared: the project focuses on discharges from industry, and on reducing discharges of harmful substances in Poland and the Baltic countries in particular, but also in Finland and Sweden.