ESTONIAN ENVIRONMENTAL REVIEW 2009

8.4. Coastal waters
The Baltic Sea is the world’s second-largest body of
brackish water after the Black Sea. Due to its low salinity,
the Baltic Sea is not very rich in species, but there are
nevertheless many important species and habitats with
importance on the level of Europe and world in terms of
biological diversity. The primary environmental problems
for the Baltic Sea are eutrophication due to the influx of
wastewater into the sea, invasion of alien species and
oil pollution.
The following primarily focuses on the sea bottom
habitats and inhabitants of the Estonian coastal waters
and related aspects.
8.4.1. Habitats
Annex I to the European Union Habitat Directive lists
priority habitats, protection of which requires the creation
of special areas to be protected. Six of the maritime
biotopes listed in the directive are found in Estonia: large
shallow inlets K and bays; sandbanks which are slightly
covered by seawater all of the time; estuaries; mudflats
and sandflats not covered by seawater at low tide; coastal
lagoons and reefs. In addition, Boreal Baltic islets and
small islands fall into this category.
Of these habitats, sandbanks are the most frequently
occurring in Estonian coastal waters, which are mainly
concentrated in the western Estonian coastal waters
and Väinameri area. Sandbanks are characterized by
the occurrence of higher plants, including eel-grass,
pondweed and horned pondweed (photograph 8.1).
Reefs are a fairly common habitat type as well. They are
found in seaside areas (such as the western and northern
coast of Vormsi, Saaremaa’s western coast, Pakri island
area) and in banks in the area of open sea (Neugrund,
Apollo etc). In shallower depths on banks near the coast,
biotic communities of a perennial brown alga, bladder
wrack are characteristic (photograph 8.2), but in general
perennial plants are lacking in the more open areas and
blue mussels (photograph 8.3) and ephemeral filamentous
macroalgae are typically predominant. Wide and smaller
shallow bays (inlets), coastal lakes (lagoons L ) and to a
great extent mudflats and sandflats M as well, are found
only in the coastal waters of western Estonia and the
islands. The only area with estuary status is Matsalu Bay.
In all four of the last-mentioned habitats, a characteristic
feature is the occurrence of higher plants and charophytes
(photograph 8.4).
Photograph 8.1. Sandbank with eelgrass community.
Photograph 8.2. Reef with bladder wrack community.
Photograph 8.3. Reef with blue mussel community.
Photograph 8.4. Estuary with charophyte community.
K
Inlet – small, shallow bay.
L
Lagoons – coastal lakes created when shallow bays became detached from the sea.
M
Mudflats and sandflats – a coastal area left dry temporarily due to water level variation.
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