Site details

(lookup in gazetteer)
Flag of International
1 star - Not protected
Normal Focal Site

Map type: Google Maps  SVG (dynamic)  Image (static)

Station F3, Middle part of the Gulf of Finland, Baltic Sea. Bloom of bluegreen algae. Photo: J Kotta

Synoptic description of site:

Represent the deeper part (80 m) of the Gulf of Finland in the northern Baltic Sea. The site is characterised by temporal anoxic condition due to the natural variability in salinity stratification of the gulf.

Extensive description of site:

The Gulf of Finland is a direct extension of the Baltic Proper, the Baltic Sea. There is no threshhold at the opening of the Gulf, and the maximum depth is some 100 m. The bottom depth decreases towards the east. The Gulf of Finland is influenced by the inflows of saline water from the Kattegat/Skagerrak. Approximately one fourth of the total river water volume, received by the Baltic Sea, enters directly into the Gulf of Finland. Occasionally the presence of a strong halocline may create temporal anoxia in the sediment.

Habitats present:
Seagrass beds 

Description of fauna and flora:

The fauna is well documented, and has been researched since 1965. Owing to low salinity, short developing time and isolation, only a limited number of species have been able to adapt to the local conditions. Soft-bottom assemblages below the thermocline show particularly low diversity consisting of only a few species of macrofauna and about 40 to 50 meiofauna species.

Human impact:

The area is subjected to moderate levels of pollution from Tallinn and Helsinki Cities.


All facilities for marine biodiversity research are available, from seagoing research vessels, equipped laboratories, offices, and library at Estonian Marine Institute.

Available database and website:

The inventory of biota and hydrophysical variables is available in the database of the Estonian National Monitoring (updated at the Estonian Marine Institute). All the main research organisations have their own websites.

Commitment and ongoing research:

The Estonian Marine Institute is involved in the monitoring activities of the site. Currently various hydrophysical, hydrochemical and biological (e.g. phytoplankton, zooplankton, phytobenthos, zoobenthos, fish) investigations are carried out related to the biodiversity of the site.