Baltic Sea
For disambiguation, see Baltic.The
Baltic Sea is located in
Northern Europe, from 53°N to 66°N
latitude and from 20°E to 26°E
longitude. It is bounded by the
Scandinavian Peninsula, the mainland of
Northern Europe,
Eastern Europe and
Central Europe, and the
Danish islands. It drains into the
Kattegat by way of the
Öresund, the
Great Belt and the
Little Belt. The Kattegat continues through the
Skagerrak into the
North Sea and the
Atlantic Ocean. The Baltic Sea is linked to the
White Sea by the
White Sea Canal and to the North Sea by the
Kiel Canal.
The first to name it the
Baltic Sea was
Adam of Bremen and he seems to have based it on a large island,
Baltia, mentioned by
Xenophon and located in northern Europe.
Etymology
The origin of the name is speculative. The first to mention
"Mare Balticum" was
Adam of Bremen in the 11th century. He may have alluded to the mythical North European island of
Baltia mentioned by
Xenophon. Another possibly is connected to the Germanic word
belt, a name used for some of the Danish straits, while others claim it to be derived from
Latin balteus (belt).
[ [1].]. Still another proposed derivation from the
Indo-European root
bhel meaning
white, shining (note that 'baltas' means 'white' in today's
Lithuanian language, for example). The latter name could have influenced the
Baltica myth because Baltic tribes lived on the shores of the Baltic Sea in ancient times and had contacts with the
Mediterranean civilisations being a well-known source of
amber for ancient
Greece and later for the
Roman Empire. However it is indisputable that the source of the name for the
Baltic countries is the name of the Baltic Sea, not the other way around.
The name in other languages
The Baltic Sea is known by the equivalents of "East Sea", "West Sea", or "Baltic Sea" in different languages:
*In
Germanic languages, except English,
East Sea is used:
Danish (
Østersøen),
Dutch (
Oostzee),
German (
Ostsee),
Norwegian (
Østersjøen), and
Swedish (
Östersjön); in addition,
Finnish, a
Balto-Finnic language has
calqued the Swedish term as
Itämeri, disregarding the geography; the sea is west of Finland.
*In another
Balto-Finnic language,
Estonian, it is called the
West Sea (
Läänemeri).
*
Baltic Sea is used in
English; in
Latin (
Mare Balticum) and the
Romance languages French (
Mer Baltique),
Italian (
Mar Baltico),
Portuguese (
Mar Báltico) and
Spanish (
Mar Báltico); in the
Slavic languages Polish (
Morze Bałtyckie or
Bałtyk),
Bulgarian (
Baltijsko More (
Балтийско море)),
Kashubian (
Bôłt), and
Russian (
Baltiyskoye Morye (
Балтийское море)); and in the
Baltic languages Latvian (
Baltijas jūra) and
Lithuanian (
Baltijos jūra).
|
Phytoplancton bloom in the Baltic Proper (July 3, 2001) |
The Baltic Sea is a
brackish inland sea, the largest body of brackish water in the world. The fact that it does not come from the collision of plates, but is a glacially scoured river valley, accounts for its relative shallowness.
Dimensions
The Baltic sea is about 1610
km (1000
miles) long, an average of 193 km (120 mi) wide, and an average of 55 m (180 ft, 30
fathoms) deep. The maximum depth is 459 m (1506 ft), on the Swedish side of the center. The surface area is about 377,000 km² (145,522 sq mi) and the volume is about 21,000 cubic km (3129 cubic miles). The periphery amounts to about 8000 km (4968 miles) of coastline. [
2]These figures are somewhat variable because a number of different estimates have been made.
Sea ice
As a long-term average the Baltic Sea is ice covered for about 45% of its surface area at maximum annually. The ice-covered area during such a normal winter includes the
Gulf of Bothnia, the
Gulf of Finland,
Gulf of Riga and Vainameri in the Estonian archipelago. The Baltic Proper does not freeze during a normal winter, with the exception of sheltered bays and shallow lagoons such as the
Courland Lagoon). The ice reaches its maximum extent in February or March; typical ice thickness in the northernmost areas in the
Bothnian Bay is about 70 cm for landfast sea ice. The thickness decreases when moving south.
Freezing begins in the northern coast of Gulf of Bothnia typically in early November, reaching the open waters of
Bay of Bothnia, the northern basin of the Gulf of Bothnia, in early January. The
Bothnian Sea, the basin south of it, freezes on average in late February. The Gulf of Finland and the Gulf of Riga freeze typically in late January.
The ice extent depends on whether the winter is mild, moderate or severe. Severe winters can ice the regions around
Denmark and southern
Sweden, and on rare cases the whole sea is frozen, such as in 1942. In 1987 some 96% of the Baltic Sea was iced, leaving only a small patch of open water to the west of
Bornholm in the Baltic proper. Contrary to this, in milder winters the Bay of Bothnia and Gulf of Finland are the only larger areas that is ice covered, in addition to coastal fringes in more southerly locations such as the Gulf of Riga.
In spring, the Gulf of Finland and the Bothnian Sea normally thaw during late April, with some ice ridges persisting until May in the eastern Gulf of Finland. In the Bay of Bothnia ice usually stays until late May; by early June it is practically always gone.
During winter, fast ice which is attached to the shoreline, develops first, rendering the ports unusable without the services of
icebreakers.
Level ice,
ice sludge,
pancake ice or
rafter ice form in the more open regions. The gleaming expanse of ice is similar to the
Arctic, with wind-driven pack ice and ridges up to 15 m, and was noted by the ancients. Offshore of the landfast ice the ice remains very dynamic all year, because of its thickness it is relatively easy moved around by winds and therefore makes up large ridges and pile up against the landfast ice and shores.
The ice cover is the main habitat only for a larger few species. The largest of them are the seals that both feed and breed on the ice. Although the sea ice also harbors several species of algae that live in the bottom and inside brine pockets in the ice.
Hydrography
The Baltic Sea flows out through the
Danish straits; however, the flow is complex. A surface layer of brackish water discharges 940 cubic km per year into the
North Sea. Due to the difference in
salinity, a sub-surface layer of more saline water moving in the opposite direction brings in 475 cubic km per year. It mixes very slowly with the upper waters, resulting in a salinity gradient from top to bottom, with most of the salt water remaining below 40 to 70 m deep. The general circulation is counterclockwise: northwards along its eastern boundary, and south along the western one.(Alhonen 88)
The difference between the outflow and the inflow comes entirely from fresh water. More than 250 streams drain a basin of about 1.6 million square km, contributing a volume of 660 cubic km per year to the Baltic. They include the major rivers of north Europe, such as the
Oder, the
Vistula, the
Neman, the
Daugava and the
Neva. Some of this water is polluted. Additional fresh water comes from the difference of
precipitation less evaporation, which is positive.
An important source of salty water are infrequent inflows of
North Sea water into the Baltic. Such inflows, important to the Baltic ecosystem becuse of the oxygen they transport into the Baltic deeps, used to happen on average every 4-5 years until the 1980s. In recent decades they have become less frequent. The latest three occurred in 1983, 1993 and 2003 suggesting a new inter-inflow period of about 10 years. Despite the influx of salt water in the lower levels, the Baltic is still more of a lake or river than a sea. Tides are negligible. Wave height in calm weather varies between 2 and 3 m. Violent and sudden storms often sweep the surface, due to large transient temperature differences and a long reach of wind. Seasonal winds also cause small changes in sea level, of the order of 0.5 m.(Alhonen 88)
Salinity
The Baltic Sea's
salinity is much lower than the ocean's, as a result of abundant freshwater runoff from the surrounding land; indeed, runoff contributes roughly 1/40th its total volume.(Alhonen 88) It varies from 0.1% in the north to 0.6-0.8% in the center. Below 40-70 m, it can be as much as 1.5-2.0%. A lateral salinity gradient also exists, from most saline in the northern
Kattegat to least saline in the northern
Gulf of Bothnia.
The most saline water remains on the bottom, creating a barrier to the exchange of
oxygen and nutrients, fostering totally different maritime environments.
Regional emergence
The land is still emerging from its subsident state, which was caused by the weight of the last glaciation. Consequently, the surface area and the depth of the sea are diminishing. The uplift is about eight millimetres per year on the Finnish coast of the northernmost Gulf of Bothnia .
Subdivisions
The northern part of the Baltic Sea is known as the
Gulf of Bothnia, of which the northernmost part is the
Bay of Bothnia or
Bothnian Bay. The more roundish southern basin of the gulf is called
Bothnian Sea and immediately to the south of it lies the
Sea of Åland. The
Gulf of Finland connects the Baltic Sea with
St Petersburg. The
Gulf of Riga lies between the
Latvian capital city of
Riga and the
Estonian island of
Saaremaa.
The
Northern Baltic Sea lies between the
Stockholm area, southwestern Finland and Estonia. The
Western and Eastern Gotland Basins form the major parts of the Central Baltic Sea or Baltic Proper. The
Bornholm Basin is the area east of
Bornholm, and the shallower
Arkona Basin extends from Bornholm to the Danish isles of
Falster and
Zealand.
In the south, the
Bay of Gdańsk lies east of the
Hel peninsula on the Polish coast and west of
Sambia in
Kaliningrad Oblast. The
Bay of Pomerania lies north of the islands of
Usedom and
Wolin, east of
Rügen. Between Falster and the German coast lie the
Bay of Mecklenburg and
Bay of Lübeck. The westernmost part of the Baltic Sea is the
Bay of Kiel. The three
Danish straits, the
Great Belt, the
Little Belt and
The Sound (Öresund), connect the Baltic Sea with the
Kattegat bay and
Skagerrak strait in the
North Sea. The confluence of these two seas at
Skagen on the northern tip of
Denmark is a visual spectacle visited by many tourists each year.
Land use
The Baltic sea drainage basin is roughly four times the surface area of the sea itself. About 48% of the region is forested, with Sweden and Finland containing the majority of the forest, especially around the Gulfs of Bothnia and Finland.
About 20% of the land is used for agriculture and pasture, mainly in Poland and around the edge of the Baltic Proper, in Germany, Denmark and Sweden. About 17% of the basin is unused open land with another 8% of wetlands. Most of the latter are in the Gulfs of Bothnia and Finland.
The rest of the land is heavily populated.
Demographics
About 85 million people live in the Baltic drainage basin, 15 million within 10 km of the coast and 29 million within 50 km of the coast. Around 22 million live in population centers of over 250,000 . 90% of these are concentrated in the 10 km band around the coast. Of the nations containing all or part of the basin, Poland includes 45% of the 85 million, Russia 12%, Sweden 10% and the others (see below) less than 6% each.
The Baltic Sea somewhat resembles a
riverbed, with two tributaries, the
Gulf of Finland and
Gulf of Bothnia.
Geological surveys show that there was a river in the area prior to the
Pleistocene: the
Eridanos. Several
glaciation episodes during the
Pleistocene scooped out the river bed into the sea basin. By the time of the last, or
Eemian interglacial (
MIS 5e), the Eemian sea was in place.
From that time the waters underwent a geologic history summarized under the names listed below. Many of the stages are named after marine animals (e.g., the
Littorina mollusk) that are clear markers of changing water temperatures and salinity.
The factors that determined the sea's characteristics were the submergence or emergence of the region due to the weight of ice and subsequent isostatic readjustment, and the connecting channels it found to the
North Sea-
Atlantic, either through the straits of
Denmark or at what are now the large lakes of
Sweden, and the
White Sea-
Arctic Sea.
*
Eemian Sea, 130,000-115,000 BP
*
Baltic ice lake, 12,600-10,300 BP
*
Yoldia Sea, 10,300-9500 BP
*
Ancylus Lake, 9500-8000 BP
*
Mastogloia Sea 8000 BP-7500 BP
*
Littorina Sea, 7500-4000 BP
*
Post-littorina Sea 4000 BP-current
At the time of the
Roman Empire, the Baltic Sea was known as the
Mare Suebicum or
Mare Sarmaticum.
Tacitus in his AD
98 Agricola and
Germania described the Mare Suebicum, named for the
Suebi tribe, during the spring months, as a
brackish sea when the ice on the Baltic Sea broke apart and chunks floated about. The
Sarmatian tribes inhabited Eastern Europe and southern Russia.
Jordanes called it the
Germanic Sea in his work the
Getica.
Since the
Viking age, the Scandinavians have called it "the Eastern Lake" (
Austmarr, "Eastern Sea", appears in the
Heimskringla and
Eystra salt appears in
Sörla þáttr), but
Saxo Grammaticus recorded in
Gesta Danorum an older name
Gandvik,
"-vik" being
Old Norse for "bay", which implies that the Vikings correctly regarded it as an inlet of the sea. (Another form of the name, "Grandvik", attested in at least one English translation of Gesta Danorum, is likely to be a misspelling.)
In addition to
fish the sea also provides
amber, especially from its southern shores. The bordering countries have traditionally provided
lumber, ,
flax,
hemp, and
furs. Sweden had from early medieval times also a flourishing
mining industry, especially on
iron ore and
silver.
Poland had and still has extensive
salt mines. All this has provided for rich trading since the Roman times.
In the early Middle Ages,
Vikings of Scandinavia fought for control over the sea with
Slavic Pomeranians. The Vikings used the rivers of Russia for trade routes, finding their way eventually to the
Black Sea and southern Russia.
Lands next to the sea's eastern shore were among the last in Europe to be converted into
Christianity in the
Northern Crusades:
Finland in the 12th century by the Swedes, and what are now
Estonia and
Latvia in the early 13th century by the Danes and the Germans (
Livonian Brothers of the Sword). The powerful German
Teutonic Knights gained control over most of the southern and eastern shore of the Baltic Sea, while fighting the
Poles, the
Danes, the
Swedes, the
Russians of ancient
Novgorod, and the
Lithuanians (latest of all Europeans to convert to Christianity).
Later, the strongest economic force in Northern Europe became the
Hanseatic league, which used the Baltic Sea to establish trade routes between its member cities. In the 16th and early 17th centuries,
Poland,
Denmark and
Sweden fought wars for
Dominium Maris Baltici (Ruling over the Baltic Sea). Eventually, it was the
Swedish Empire that virtually encompassed the Baltic Sea. In Sweden the sea was then referred to as
Mare Nostrum Balticum (Our Baltic Sea).
In the 18th century
Russia and
Prussia became the leading powers over the sea. Russia's
Peter the Great saw the strategic importance of the Baltic and decided to found his new capital,
St Petersburg at the mouth of the
Neva river at the east end of the
Gulf of Finland. There was much trading not just within the Baltic region but also with the North Sea region, especially eastern
England and the
Netherlands: their fleets needed the Baltic timber, tar, flax and hemp.
During the
Crimean War a joint fleet of
Britain and
France attacked the Russian fortresses by bombarding
Sveaborg, which guards
Helsinki, and
Kronstadt, which guards
St Petersburg, and destroying
Bomarsund in the
Åland Islands. After the unification of
Germany in
1871, the whole southern coast became German. The
First World War was partly fought in the Baltic Sea. After
1920 Poland returned to the Baltic Sea, and the Polish ports of
Gdynia and
Gdańsk became leading ports of the Baltic.
During
the Second World War Germany reclaimed all of the southern shore and much of the eastern by occupying Poland and the
Baltic states. In
1945 the Baltic Sea became a mass grave for drowned people on torpedoed
refugee ships.
As of 2004, the sinking of the
Wilhelm Gustloff remains the worst
maritime disaster, killing (very roughly) 9,000 people. In 2005, a Russian group of scientists found over 5,000 airplane wrecks, sunken warships, etc., mainly from
the Second World War, lying at the bottom of the sea.
After
1945 the sea was a border between opposing military blocks: in the case of military conflict in Germany, in parallel with a Soviet offensive towards the
Atlantic Ocean, communist Poland's fleet was prepared to invade the Danish isles.
In May
2004 the Baltic Sea became almost completely a
European Union internal sea when the
Baltic states and
Poland became parts of the European Union, leaving only the Russian
metropolis of
St Petersburg and the
exclave of
Kaliningrad Oblast as non-EU areas.
The Baltic Sea starts to get very rough with the October storms. These winter storms have been the cause of many shipwrecks, for example, the sinking of the ferry
M/S Estonia en route from
Tallinn, Estonia to
Stockholm, Sweden in
1994, which claimed the lives of hundreds. But thanks to the cold brackish water where the
shipworm cannot survive, the sea is a time capsule for centuries-old shipwrecks. Perhaps the most famous one is the
Vasa.
Approximately 100,000 square km of the seafloor (¼ of the total area) is a variable dead zone. The more saline (and therefore denser) water remains on the bottom, isolating it from surface waters and the atmosphere. This leads to decreased oxygen concentrations within the zone. It is mainly bacteria that grow in it, digesting organic material and releasing hydrogen sulfide. Because of this large anaerobic zone, the seafloor ecology differs from that of the neighbouring Atlantic.
The low salinity of the Baltic sea has led to the evolution of many slightly divergent species, such as the Baltic Sea
herring, which is a smaller variant of the
Atlantic herring. The
benthic fauna consists mainly of
Monoporeia affinis, which is originally a freshwater species. The lack of
tides has affected the marine species as compared with the Atlantic.
Construction of the
Great Belt Bridge (
1997) and
Oresund Bridge (
1999) over the
international waterway of the
Danish Straits has limited the Baltic Sea to medium-sized vessels. The Baltic Sea is the main trade route for export of Russian oil. Many of the neighboring countries are concerned about this, since a major oil leak would be disastrous in the Baltic given the slow exchange of water and the many unique species. The tourism industries, especially in economies dependent on tourism like northeastern Germany, are naturally very concerned.
Shipbuilding is practiced in many large shipyards around the Baltic:
Gdańsk,
Szczecin in Poland,
HDW in
Kiel, Germany,
Karlskrona and
Kockums in
Malmö, Sweden, and
Rauma,
Turku,
Helsinki in Finland,
Rīga,
Liepāja in Latvia and
Klaipėda in Lithuania.
There are several cargo and passenger
ferry operators on the Baltic Sea, such as
Silja Line,
Polferries,
Viking Line,
Tallink and
Superfast Ferries.
Countries that border on the sea:
*
Denmark*
Estonia*
Finland*
Germany*
Latvia*
Lithuania*
Poland*
Russia*
SwedenCountries that are in the drainage basin but do not border on the sea:
*
Belarus*
Czech Republic*
Norway*
Slovakia*
Ukraine*
Åland Islands (
Finland,
autonomous)
*
Archipelago Sea (
Finland)
**
Pargas**
Nagu**
Korpo**
Houtskär**
Kustavi*
Bornholm (
Denmark)
*
Gotland (
Sweden)
*
Hailuoto (
Finland)
*
Hiiumaa (
Estonia)
*
Kotlin (
Russia)
*
Muhu (
Estonia)
*
Öland (
Sweden)
*
Rügen (
Germany)
*
Saaremaa (
Estonia)
*
Stockholm archipelago (
Sweden)
*
Usedom or Uznam (split between
Germany and
Poland)
*
Valassaaret (
Finland)
*
Wolin (
Poland)
The biggest coastal cities:
*
St Petersburg (Russia) 4,700,000
*
Stockholm (Sweden) 774,411 (metropolitan area 1,729,274)
*
Riga (Latvia) 760,000
*
Helsinki (Finland) 559,716 (metropolitan area 1,200,000)
*
Copenhagen (Denmark) 502,204 (metropolitan area 1,823,109) (facing the
Sound)
*
Gdańsk (Poland) 462,700 (
metropolitan area 1,041,000)
*
Szczecin (Poland) 413,600
*
Tallinn (Estonia) 401,774
*
Kaliningrad (Russia) 400,000
*
Malmö (Sweden) 259,579 (facing the
Sound)
*
Gdynia (Poland) 255,600
*
Kiel (Germany) 250,000
*
Lübeck (Germany) 216,100
*
Rostock (Germany) 212,700
*
Klaipėda (Lithuania) 194,400
*
Turku (Finland) 175,000
Important ports (though not big cities):
*
Kotka (Finland) 55,000
*
Świnoujście (Poland) 50,000
*
Ventspils (Latvia) 44,000
*
Baltiysk (Russia) 20,000
*
Hanko (Finland) 10,000
*
Ports of the Baltic Sea*
Baltic*
Baltic region*
Council of the Baltic Sea States*
Baltic states*
Scandinavia*
Northern Europe*
List of rivers of the Baltic Sea*Fairbridge, Rhodes.
The Encyclopedia of Oceanography. Pentti Alhonen, "Baltic Sea", pp. 87-91. New York: Van Nostrand Reinhold Company, 1966.
*
The Baltic Sea Portal - a site maintained by the
Finnish Institute of Marine Research (FIMR) (in English, Finnish, Swedish and Estonian)
*
Encyclopedia of Baltic History*
1493 H. Schedel Map with Mare Germanicum *
Old shipwrecks in the Baltic
*
How the Baltic Sea was changing - Prehistory of the Baltic from the
Polish Geological Institute*
Late Weichselian and Holocene shore displacement history of the Baltic Sea in Finland - more prehistory of the Baltic from the
Department of Geography of the
University of Helsinki*
Baltic Environmental Atlas: Interactive map of the Baltic Sea region*
The Baltic Sea Environment*
Baltic Sea Photos
