[2] The last fully fresh water stage in the Baltic basin, the Ancylus Lake ended at 9,800 ka cal.
BP and east of the Darβ Sill which is at the western end of the Baltic Sea, at sites so far studied, are after 8.5 ka cal.
Transitional regions in the eastern Baltic show positive relative sea level tendencies until between 7.5 and about 7.1 ka cal BP, when they become negative.
The final melting of the Laurentide ice sheet followed by much lower rate of global sea-level rise took place at this general time, between 8 and 7 ka cal.
[10] A transgression of the Baltic widened its ocean link, allowing it to reach a peak of salinity during the warmer Atlantic period of European climatology.
[2] Diatom studies of the sediments of the Landsort deep off Sweden suggest that the highest surface water salinities occurred between 7.1 and 5.4 ka BP,[11] about the time of the Littorina Sea high stand.
[2] Notable exceptions include steep terraces such as the Øresund where the recession of sea level exposes less dry land.
[2] As revealed in the marine microfossil record in today's deepest part of the Baltic Sea, which includes freshwater surface diatoms Aulacoseira islandica and Stephanodiscus neoastraea,[13] before 7.1 ka cal.
[15] As brackish conditions were re-established intermediate productivity ecosystems similar to the present day Baltic Sea were established.
[16] During the period, from the Ancylus Lake, temperate deciduous forest had crept north to cover the littoral hinterland and thus coastal regions of the sea.