Vistula Lagoon million. However, major ecological considerations stand in the way. For example, mammal migration along the lagoon could be disrupted. Also, the inflow of brackish waters from the Baltic sea could result in serious unbalancing of the lagoon's freshwater ecosystem. From 1772 until 1918, the lagoon was part of the Kingdom of Prussia, which had become part of the German Empire in 1871. Between 1920 and 1946 it was split between Germany and the Free City of Danzig. At present state since 1945 its eastern part belongs to Russia (formerly USSR), Poland has 43.8% of its area at lagoon's western side.
Indian River Lagoon the west side of the lagoon at about 27°32'N (corresponding to Segment 11 of the model). In 2007, concerns were raised about the future of the lagoon system, especially in the southern half where frequent freshwater discharges seriously threatened water quality, decreasing the salinity needed by many fish species, and have contributed to large algae blooms promoted by water saturated with plant fertilizers. In the mid 1990s, the lagoon has been the subject of research on light penetration for photosynthesis in submerged aquatic vegetation. In 2010, of nitrogen and of phosphorus entered the lagoon. In 2011, a "superbloom" of phytoplankton