Baltic Sea
Sea in northern Europe
The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North and Central European Plain regions.
The sea stretches from 53°N to 66°N latitude and from 10°E to 30°E longitude. It is a shelf sea and marginal sea of the Atlantic with limited water exchange between the two, making it an inland sea. The Baltic Sea drains through the Danish straits into the Kattegat by way of the Øresund, Great Belt and Little Belt. It includes the Gulf of Bothnia (divided into the Bothnian Bay and the Bothnian Sea), the Gulf of Finland, the Gulf of Riga and the Bay of Gdańsk.
The "Baltic Proper" is bordered on its northern edge, at latitude 60°N, by Åland and the Gulf of Bothnia, on its northeastern edge by the Gulf of Finland, on its eastern edge by the Gulf of Riga, and in the west by the Swedish part of the southern Scandinavian Peninsula.
The Baltic Sea is connected by artificial waterways to the White Sea via the White Sea–Baltic Canal and to the German Bight of the North Sea via the Kiel Canal.
Definitions.
Administration.
The Helsinki Convention on the Protection of the Marine Environment of the Baltic Sea Area includes the Baltic Sea and the Kattegat, without calling Kattegat a part of the Baltic Sea, "For the purposes of this Convention the 'Baltic Sea Area' shall be the Baltic Sea and the Entrance to the Baltic Sea, bounded by the parallel of the Skaw in the Skagerrak at 57°44.43'N."
Traffic history.
Historically, the Kingdom of Denmark collected Sound Dues from ships at the border between the ocean and the land-locked Baltic Sea, in tandem: in the Øresund at Kronborg castle near Helsingør; in the Great Belt at Nyborg; and in the Little Belt at its narrowest part then Fredericia, after that stronghold was built. The narrowest part of Little Belt is the "Middelfart Sund" near Middelfart.
Oceanography.
Geographers widely agree that the preferred physical border between the Baltic and North Seas is the Langelandsbælt (the southern part of the Great Belt strait near Langeland) and the Drogden-Sill strait. The Drogden Sill is situated north of Køge Bugt and connects Dragør in the south of Copenhagen to Malmö; it is used by the Øresund Bridge, including the "Drogden Tunnel". By this definition, the Danish straits is part of the entrance, but the Bay of Mecklenburg and the Bay of Kiel are parts of the Baltic Sea.
Another usual border is the line between Falsterbo, Sweden, and Stevns Klint, Denmark, as this is the southern border of Øresund. It is also the border between the shallow southern Øresund (with a typical depth of 5–10 meters only) and notably deeper water.
Hydrography and biology.
Drogden Sill (depth of ) sets a limit to Øresund and Darss Sill (depth of ), and a limit to the Belt Sea. The shallow sills are obstacles to the flow of heavy salt water from the Kattegat into the basins around Bornholm and Gotland.
The Kattegat and the southwestern Baltic Sea are well oxygenated and have a rich biology. The remainder of the Sea is brackish, poor in oxygen, and in species. Thus, statistically, the more of the entrance that is included in its definition, the healthier the Baltic appears; conversely, the more narrowly it is defined, the more endangered its biology appears.
Etymology and nomenclature.
Tacitus called it the Suebic Sea, Latin: after the Germanic people of the Suebi, and Ptolemy "Sarmatian Ocean" after the Sarmatians, but the first to name it the "Baltic Sea" () was the eleventh-century German chronicler Adam of Bremen. The origin of the latter name is speculative and it was adopted into Slavic and Finnic languages spoken around the sea, very likely due to the role of Medieval Latin in cartography. It might be connected to the Germanic word "belt", a name used for two of the Danish straits, the Belts, while others claim it to be directly derived from the source of the Germanic word, Latin "belt". Adam of Bremen himself compared the sea with a belt, stating that it is so named because it stretches through the land as a belt ("Balticus, eo quod in modum baltei longo tractu per Scithicas regiones tendatur usque in Greciam").
He might also have been influenced by the name of a legendary island mentioned in the "Natural History" of Pliny the Elder. Pliny mentions an island named "Baltia" (or "Balcia") with reference to accounts of Pytheas and Xenophon. It is possible that Pliny refers to an island named Basilia ("the royal") in "On the Ocean" by Pytheas. "Baltia" also might be derived from "belt", and therein mean "near belt of sea, strait".
Others have suggested that the name of the island originates from the Proto-Indo-European root "*bʰel" meaning "white, fair", which may echo the naming of seas after colours relating to the cardinal points (as per Black Sea and Red Sea). This '*bʰel' root and basic meaning were retained in Lithuanian (as ), Latvian (as ) and Slavic (as ). On this basis, a related hypothesis holds that the name originated from this Indo-European root via a Baltic language such as Lithuanian. Another explanation is that, while derived from the aforementioned root, the name of the sea is related to names for various forms of water and related substances in several European languages, that might have been originally associated with colors found in swamps (compare Proto-Slavic "*bolto" "swamp"). Yet another explanation is that the name originally meant "enclosed sea, bay" as opposed to open sea.
In the Middle Ages the sea was known by a variety of names. The name Baltic Sea became dominant after 1600. Usage of "Baltic" and similar terms to denote the region east of the sea started only in the 19th century.
Name in other languages.
The Baltic Sea was known in ancient Latin language sources as or even . Older native names in languages that used to be spoken on the shores of the sea or near it usually indicate the geographical location of the sea (in Germanic languages), or its size in relation to smaller gulfs (in Old Latvian), or tribes associated with it (in Old Russian the sea was known as the Varanghian Sea). In modern languages, it is known by the equivalents of "East Sea", "West Sea", or "Baltic Sea" in different languages:
History.
Classical world.
At the time of the Roman Empire, the Baltic Sea was known as the 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 where the ice broke apart and chunks floated about. The Suebi eventually migrated southwest to temporarily reside in the Rhineland area of modern Germany, where their name survives in the historic region known as Swabia. Jordanes called it the "Germanic Sea" in his work, the "Getica".
Middle Ages.
In the early Middle Ages, Norse (Scandinavian) merchants built a trade empire all around the Baltic. Later, the Norse fought for control of the Baltic against Wendish tribes dwelling on the southern shore. The Norse also used the rivers of Russia for trade routes, finding their way eventually to the Black Sea and southern Russia. This Norse-dominated period is referred to as the Viking Age.
Since the Viking Age, the Scandinavians have referred to the Baltic Sea as "Austmarr" ("Eastern Sea"). "Eastern Sea", appears in the "Heimskringla" and "Eystra salt" appears in "Sörla þáttr". 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 within today's borders of Poland, Russia and Lithuania. First mentions of amber deposits on the South Coast of the Baltic Sea date back to the 12th century. The bordering countries have also traditionally exported lumber, wood tar, flax, hemp and furs by ship across the Baltic. Sweden had from early medieval times exported iron and silver mined there, while Poland had and still has extensive salt mines. Thus, the Baltic Sea has long been crossed by much merchant shipping.
The lands on the Baltic's eastern shore were among the last in Europe to be converted to Christianity. This finally happened during the Northern Crusades: Finland in the twelfth century by Swedes, and what are now Estonia and Latvia in the early thirteenth century by Danes and Germans (Livonian Brothers of the Sword). The Teutonic Order gained control over parts of the southern and eastern shore of the Baltic Sea, where they set up their monastic state. Lithuania was the last European state to convert to Christianity.
An arena of conflict.
In the period between the 8th and 14th centuries, there was much piracy in the Baltic from the coasts of Pomerania and Prussia, and the Victual Brothers held Gotland.
Starting in the 11th century, the southern and eastern shores of the Baltic were settled by migrants mainly from Germany, a movement called the "Ostsiedlung" ("east settling"). Other settlers were from the Netherlands, Denmark, and Scotland. The Polabian Slavs were gradually assimilated by the Germans. Denmark gradually gained control over most of the Baltic coast, until she lost much of her possessions after being defeated in the 1227 Battle of Bornhöved.
In the 13th to 16th centuries, the strongest economic force in Northern Europe was the Hanseatic League, a federation of merchant cities around the Baltic Sea and the North Sea. In the sixteenth and early seventeenth centuries, Poland, Denmark, and Sweden fought wars for "Dominium maris baltici" ("Lordship over the Baltic Sea"). Eventually, it was Sweden that virtually encompassed the Baltic Sea. In Sweden, the sea was then referred to as "Mare Nostrum Balticum" ("Our Baltic Sea"). The goal of Swedish warfare during the 17th century was to make the Baltic Sea an all-Swedish sea ("Ett Svenskt innanhav"), something that was accomplished except the part between Riga in Latvia and Stettin in Pomerania. However, the Dutch dominated the Baltic trade in the seventeenth century.
In the eighteenth century, Russia and Prussia became the leading powers over the sea. Sweden's defeat in the Great Northern War brought Russia to the eastern coast. Russia became and remained a dominating power in the Baltic. Russia's Peter the Great saw the strategic importance of the Baltic and decided to found his new capital, Saint 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 British and French fleet attacked the Russian fortresses in the Baltic; the case is also known as the Åland War. They bombarded Sveaborg, which guards Helsinki; and Kronstadt, which guards Saint Petersburg; and they destroyed Bomarsund in Åland. After the unification of Germany in 1871, the whole southern coast became German. World War I was partly fought in the Baltic Sea. After 1920 Poland was granted access to the Baltic Sea at the expense of Germany by the Polish Corridor and enlarged the port of Gdynia in rivalry with the port of the Free City of Danzig.
After the Nazis' rise to power, Germany reclaimed the Memelland and after the outbreak of the Eastern Front (World War II) occupied the Baltic states. In 1945, the Baltic Sea became a mass grave for retreating soldiers and refugees on torpedoed troop transports. The sinking of the "Wilhelm Gustloff" remains the worst maritime disaster in history, killing (very roughly) 9,000 people. In 2005, a Russian group of scientists found over five thousand airplane wrecks, sunken warships, and other material, mainly from World War II, on the bottom of the sea.
Since World War II.
Since the end of World War II, various nations, including the Soviet Union, the United Kingdom and the United States have disposed of chemical weapons in the Baltic Sea, raising concerns of environmental contamination. Today, fishermen occasionally find some of these materials: the most recent available report from the Helsinki Commission notes that four small scale catches of chemical munitions representing approximately of material were reported in 2005. This is a reduction from the 25 incidents representing of material in 2003. Until now, the U.S. Government refuses to disclose the exact coordinates of the wreck sites. Deteriorating bottles leak mustard gas and other substances, thus slowly poisoning a substantial part of the Baltic Sea.
After 1945, the German population was expelled from all areas east of the Oder-Neisse line, making room for new Polish and Russian settlement. Poland gained most of the southern shore. The Soviet Union gained another access to the Baltic with the Kaliningrad Oblast, that had been part of German-settled East Prussia. The Baltic states on the eastern shore were annexed by the Soviet Union. The Baltic then separated opposing military blocs: NATO and the Warsaw Pact. Neutral Sweden developed incident weapons to defend its territorial waters after the Swedish submarine incidents. This border status restricted trade and travel. It ended only after the collapse of the Communist regimes in Central and Eastern Europe in the late 1980s.
Finland and Sweden joined NATO in 2023 and 2024, respectively, making the Baltic Sea almost entirely surrounded by the alliance's members, leading some commentators to label the sea a ″NATO lake″. Such an arrangement has also existed for the European Union (EU) since May 2004 following the accession of the Baltic states and Poland. The remaining non-NATO and non-EU shore areas are Russian: the Saint Petersburg area and the Kaliningrad Oblast exclave.
Storms and storm floods.
Winter storms begin arriving in the region during October. These have caused numerous shipwrecks, and contributed to the extreme difficulties of rescuing passengers of the ferry MS "Estonia" en route from Tallinn, Estonia, to Stockholm, Sweden, in September 1994, which claimed the lives of 852 people. Older, wood-based shipwrecks such as the "Vasa" tend to remain well-preserved, as the Baltic's cold and brackish water does not suit the shipworm.
Storm surge floods are generally taken to occur when the water level is more than one metre above normal. In Warnemünde about 110 floods occurred from 1950 to 2000, an average of just over two per year.
Historic flood events were the All Saints' Flood of 1304 and other floods in the years 1320, 1449, 1625, 1694, 1784 and 1825. Little is known of their extent. From 1872, there exist regular and reliable records of water levels in the Baltic Sea. The highest was the flood of 1872 when the water was an average of above sea level at Warnemünde and a maximum of above sea level in Warnemünde. In the last very heavy floods the average water levels reached above sea level in 1904, in 1913, in January 1954, on 2–4 November 1995 and on 21 February 2002.
Geography.
Geophysical data.
An arm of the North Atlantic Ocean, the Baltic Sea is enclosed by Sweden and Denmark to the west, Finland to the northeast, and the Baltic countries to the southeast.
It is about long, an average of wide, and an average of deep. The maximum depth is which is on the Swedish side of the center. The surface area is about and the volume is about . The periphery amounts to about of coastline.
The Baltic Sea is one of the largest brackish inland seas by area, and occupies a basin (a "Zungenbecken") formed by glacial erosion during the last few ice ages.
Extent.
The International Hydrographic Organization defines the limits of the Baltic Sea as follows:
Bordered by the coasts of Germany, Denmark, Poland, Sweden, Finland, Russia, Estonia, Latvia, and Lithuania, it extends north-eastward of the following limits:
*"In the Little Belt." A line joining Falshöft () and Vejsnæs Nakke (Ærø: ).
*"In the Great Belt." A line joining Gulstav (South extreme of Langeland Island) and Kappel Kirke () on Island of Lolland.
*"In the Guldborg Sound." A line joining Flinthorne-Rev and Skjelby ().
*"In the Sound." A line joining Stevns Lighthouse () and Falsterbo Point ().
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 rounded 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 Saint 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 the Sambia Peninsula in Kaliningrad Oblast. The Bay of Pomerania lies north of the islands of Usedom/Uznam 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"/"Øresund"), connect the Baltic Sea with the Kattegat and Skagerrak strait in the North Sea.
Temperature and ice.
The water temperature of the Baltic Sea varies significantly depending on exact location, season and depth. At the Bornholm Basin, which is located directly east of the island of the same name, the surface temperature typically falls to during the peak of the winter and rises to during the peak of the summer, with an annual average of around . A similar pattern can be seen in the Gotland Basin, which is located between the island of Gotland and Latvia. In the deep of these basins the temperature variations are smaller. At the bottom of the Bornholm Basin, deeper than , the temperature typically is , and at the bottom of the Gotland Basin, at depths greater than , the temperature typically is . Generally, offshore locations, lower latitudes and islands maintain maritime climates, but adjacent to the water continental climates are common, especially on the Gulf of Finland. In the northern tributaries the climates transition from moderate continental to subarctic on the northernmost coastlines.
On the long-term average, the Baltic Sea is ice-covered at the annual maximum for about 45% of its surface area. The ice-covered area during such a typical winter includes the Gulf of Bothnia, the Gulf of Finland, the Gulf of Riga, the archipelago west of Estonia, the Stockholm archipelago, and the Archipelago Sea southwest of Finland. The remainder of the Baltic does not freeze during a normal winter, except sheltered bays and shallow lagoons such as the Curonian Lagoon. The ice reaches its maximum extent in February or March; typical ice thickness in the northernmost areas in the Bothnian Bay, the northern basin of the Gulf of Bothnia, is about for landfast sea ice. The thickness decreases farther south.
Freezing begins in the northern extremities of the Gulf of Bothnia typically in the middle of November, reaching the open waters of the Bothnian Bay in early January. The Bothnian Sea, the basin south of Kvarken, freezes on average in late February. The Gulf of Finland and the Gulf of Riga freeze typically in late January. In 2011, the Gulf of Finland was completely frozen on 15 February.
The ice extent depends on whether the winter is mild, moderate, or severe. In severe winters ice can form around southern Sweden and even in the Danish straits. According to the 18th-century natural historian William Derham, during the severe winters of 1703 and 1708, the ice cover reached as far as the Danish straits. Frequently, parts of the Gulf of Bothnia and the Gulf of Finland are frozen, in addition to coastal fringes in more southerly locations such as the Gulf of Riga. This description meant that the whole of the Baltic Sea was covered with ice.
Since 1720, the Baltic Sea has frozen over entirely 20 times, most recently in early 1987, which was the most severe winter in Scandinavia since 1720. The ice then covered . During the winter of 2010–11, which was quite severe compared to those of the last decades, the maximum ice cover was , which was reached on 25 February 2011. The ice then extended from the north down to the northern tip of Gotland, with small ice-free areas on either side, and the east coast of the Baltic Sea was covered by an ice sheet about wide all the way to Gdańsk. This was brought about by a stagnant high-pressure area that lingered over central and northern Scandinavia from around 10 to 24 February. After this, strong southern winds pushed the ice further into the north, and much of the waters north of Gotland were again free of ice, which had then packed against the shores of southern Finland. The effects of the aforementioned high-pressure area did not reach the southern parts of the Baltic Sea, and thus the entire sea did not freeze over. However, floating ice was additionally observed near Świnoujście harbor in January 2010.
In recent years before 2011, the Bothnian Bay and the Bothnian Sea were frozen with solid ice near the Baltic coast and dense floating ice far from it. In 2008, almost no ice formed except for a short period in March.
During winter, fast ice, which is attached to the shoreline, develops first, rendering ports unusable without the services of icebreakers. Level ice, ice sludge, pancake ice, and 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 . Offshore of the landfast ice, the ice remains very dynamic all year, and it is relatively easily moved around by winds and therefore forms pack ice, made up of large piles and ridges pushed against the landfast ice and shores.
In spring, the Gulf of Finland and the Gulf of Bothnia normally thaw in late April, with some ice ridges persisting until May in the eastern extremities of the Gulf of Finland. In the northernmost reaches of the Bothnian Bay, ice usually stays until late May; by early June it is practically always gone. However, in the famine year of 1867 remnants of ice were observed as late as 17 July near Uddskär. Even as far south as Øresund, remnants of ice have been observed in May on several occasions; near Taarbaek on 15 May 1942 and near Copenhagen on 11 May 1771. Drift ice was also observed on 11 May 1799.
The ice cover is the main habitat for two large mammals, the grey seal ("Halichoerus grypus") and the Baltic ringed seal ("Pusa hispida botnica"), both of which feed underneath the ice and breed on its surface. Of these two seals, only the Baltic ringed seal suffers when there is not adequate ice in the Baltic Sea, as it feeds its young only while on ice. The grey seal is adapted to reproducing also with no ice in the sea. The sea ice also harbors several species of algae that live in the bottom and inside unfrozen brine pockets in the ice.
Due to the often fluctuating winter temperatures between above and below freezing, the saltwater ice of the Baltic Sea can be treacherous and hazardous to walk on, in particular in comparison to the more stable fresh water-ice sheets in the interior lakes.
Hydrography.
The Baltic Sea flows out through the Danish straits; however, the flow is complex. A surface layer of brackish water discharges per year into the North Sea. Due to the difference in salinity, by salinity permeation principle, a sub-surface layer of more saline water moving in the opposite direction brings in per year. It mixes very slowly with the upper waters, resulting in a salinity gradient from top to bottom, with most of the saltwater remaining below deep. The general circulation is anti-clockwise: northwards along its eastern boundary, and south along with the western one .
The difference between the outflow and the inflow comes entirely from fresh water. More than 250 streams drain a basin of about , contributing a volume of 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. Additional fresh water comes from the difference of precipitation less evaporation, which is positive.
An important source of salty water is infrequent inflows (also known as major Baltic inflows or MBIs) of North Sea water into the Baltic. Such inflows, important to the Baltic ecosystem because of the oxygen they transport into the Baltic deeps, happen on average once per year, but large pulses that can replace the anoxic deep water in the Gotland Deep occur about once in ten years. Previously, it was believed that the frequency of MBIs had declined since 1980, but recent studies have challenged this view and no longer display a clear change in the frequency or intensity of saline inflows. Instead, a decadal variability in the intensities of MBIs is observed with a main period of approximately 30 years.
The water level is generally far more dependent on the regional wind situation than on tidal effects. However, tidal currents occur in narrow passages in the western parts of the Baltic Sea. Tides can reach in the Gulf of Finland.
The significant wave height is generally much lower than that of the North Sea. Quite violent, sudden storms sweep the surface ten or more times a year, due to large transient temperature differences and a long reach of the wind. Seasonal winds also cause small changes in sea level, of the order of . According to the media, during a storm in January 2017, an extreme wave above has been measured and significant wave height of around has been measured by the FMI. A numerical study has shown the presence of events with significant wave heights. Those extreme waves events can play an important role in the coastal zone on erosion and sea dynamics.
Salinity.
The Baltic Sea is the world's largest brackish sea. Only two other brackish waters are larger according to some measurements: The Black Sea is larger in both surface area and water volume, but most of it is located outside the continental shelf (only a small fraction is inland). The Caspian Sea is larger in water volume, but—despite its name—it is a lake rather than a sea.
The Baltic Sea's salinity is much lower than that of ocean water (which averages 3.5%), as a result of abundant freshwater runoff from the surrounding land (rivers, streams and alike), combined with the shallowness of the sea itself; runoff contributes roughly one-fortieth its total volume per year, as the volume of the basin is about and yearly runoff is about .
The open surface waters of the Baltic Sea "proper" generally have a salinity of 0.3 to 0.9%, which is border-line freshwater. The flow of freshwater into the sea from approximately two hundred rivers and the introduction of salt from the southwest builds up a gradient of salinity in the Baltic Sea. The highest surface salinities, generally 0.7–0.9%, are in the southwestern most part of the Baltic, in the Arkona and Bornholm basins (the former located roughly between southeast Zealand and Bornholm, and the latter directly east of Bornholm). It gradually falls further east and north, reaching the lowest in the Bothnian Bay at around 0.3%. Drinking the surface water of the Baltic as a means of survival would actually hydrate the body instead of dehydrating, as is the case with ocean water.
As saltwater is denser than freshwater, the bottom of the Baltic Sea is saltier than the surface. This creates a vertical stratification of the water column, a halocline, that represents a barrier to the exchange of oxygen and nutrients, and fosters completely separate maritime environments. The difference between the bottom and surface salinities varies depending on location. Overall it follows the same southwest to east and north pattern as the surface. At the bottom of the Arkona Basin (equaling depths greater than ) and Bornholm Basin (depths greater than ) it is typically 1.4–1.8%. Further east and north the salinity at the bottom is consistently lower, being the lowest in Bothnian Bay (depths greater than ) where it is slightly below 0.4%, or only marginally higher than the surface in the same region.
In contrast, the salinity of the Danish straits, which connect the Baltic Sea and Kattegat, tends to be significantly higher, but with major variations from year to year. For example, the surface and bottom salinity in the Great Belt is typically around 2.0% and 2.8% respectively, which is only somewhat below that of the Kattegat. The water surplus caused by the continuous inflow of rivers and streams to the Baltic Sea means that there generally is a flow of brackish water out through the Danish straits to the Kattegat (and eventually the Atlantic). Significant flows in the opposite direction, salt water from the Kattegat through the Danish straits to the Baltic Sea, are less regular and are known as major Baltic inflows (MBIs).
Major tributaries.
The rating of mean discharges differs from the ranking of hydrological lengths (from the most distant source to the sea) and the rating of the nominal lengths. Göta älv, a tributary of the Kattegat, is not listed, as due to the northward upper low-salinity-flow in the sea, its water hardly reaches the Baltic proper:
Coastal countries.
Countries that border the sea: Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden.
Countries lands in the outer drainage basin: Belarus, Czech Republic, Norway, Slovakia, Ukraine.
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. About 85 million people live in the Baltic drainage basin, 15 million within of the coast and 29 million within of the coast. Around 22 million live in population centers of over 250,000. 90% of these are concentrated in the 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 less than 6% each.
Cities.
The biggest coastal cities (by population):
Other important ports:
Geology.
The Baltic Sea somewhat resembles a riverbed, with two tributaries, the Gulf of Finland and Gulf of Bothnia. Geological surveys show that before the Pleistocene, instead of the Baltic Sea, there was a wide plain around a great river that paleontologists call the Eridanos. Several Pleistocene glacial episodes scooped out the river bed into the sea basin. By the time of the last, or Eemian Stage (MIS 5e), the Eemian Sea was in place. Instead of a true sea, the Baltic can even today also be understood as the common estuary of all rivers flowing into it.
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. There are a number of named and dated stages in the evolution of the Baltic Sea:
The land is still emerging isostatically from its depressed state, which was caused by the weight of ice during the last glaciation. The phenomenon is known as post-glacial rebound. Consequently, the surface area and the depth of the sea are diminishing. The uplift is about eight millimeters per year on the Finnish coast of the northernmost Gulf of Bothnia. In the area, the former seabed is only gently sloping, leading to large areas of land being reclaimed in what are, geologically speaking, relatively short periods (decades and centuries).
The "Baltic Sea anomaly".
The "Baltic Sea anomaly" is a feature on an indistinct sonar image taken by Swedish salvage divers on the floor of the northern Baltic Sea in June 2011. The treasure hunters suggested the image showed an object with unusual features of seemingly extraordinary origin. Speculation published in tabloid newspapers claimed that the object was a sunken UFO. A consensus of experts and scientists say that the image most likely shows a natural geological formation.
Biology.
Fauna and flora.
The fauna of the Baltic Sea is a mixture of marine and freshwater species. Among marine fishes are Atlantic cod, Atlantic herring, European hake, European plaice, European flounder, shorthorn sculpin and turbot, and examples of freshwater species include European perch, northern pike, whitefish and common roach. Freshwater species may occur at outflows of rivers or streams in all coastal sections of the Baltic Sea. Otherwise, marine species dominate in most sections of the Baltic, at least as far north as Gävle, where less than one-tenth are freshwater species. Further north the pattern is inverted. In the Bothnian Bay, roughly two-thirds of the species are freshwater. In the far north of this bay, saltwater species are almost entirely absent. For example, the common starfish and shore crab, two species that are very widespread along European coasts, are both unable to cope with the significantly lower salinity. Their range limit is west of Bornholm, meaning that they are absent from the vast majority of the Baltic Sea. Some marine species, like the Atlantic cod and European flounder, can survive at relatively low salinities but need higher salinities to breed, which therefore occurs in deeper parts of the Baltic Sea. The common blue mussel is the dominating animal species, and makes up more than 90% of the total animal biomass in the sea.
There is a decrease in species richness from the Danish belts to the Gulf of Bothnia. The decreasing salinity along this path causes restrictions in both physiology and habitats. At more than 600 species of invertebrates, fish, aquatic mammals, aquatic birds and macrophytes, the Arkona Basin (roughly between southeast Zealand and Bornholm) is far richer than other more eastern and northern basins in the Baltic Sea, which all have less than 400 species from these groups, with the exception of the Gulf of Finland with more than 750 species. However, even the most diverse sections of the Baltic Sea have far fewer species than the almost-full saltwater Kattegat, which is home to more than 1600 species from these groups. The lack of tides has affected the marine species as compared with the Atlantic.
Since the Baltic Sea is so young there are only two or three known endemic species: the brown alga "Fucus radicans" and the flounder "Platichthys solemdali". Both appear to have evolved in the Baltic basin and were only recognized as species in 2005 and 2018 respectively, having formerly been confused with more widespread relatives. The tiny Copenhagen cockle ("Parvicardium hauniense"), a rare mussel, is sometimes considered endemic, but has now been recorded in the Mediterranean. However, some consider non-Baltic records to be misidentifications of juvenile lagoon cockles ("Cerastoderma glaucum"). Several widespread marine species have distinctive subpopulations in the Baltic Sea adapted to the low salinity, such as the Baltic Sea forms of the Atlantic herring and lumpsucker, which are smaller than the widespread forms in the North Atlantic.
A peculiar feature of the fauna is that it contains a number of glacial relict species, isolated populations of arctic species which have remained in the Baltic Sea since the last glaciation, such as the large isopod "Saduria entomon", the Baltic subspecies of ringed seal, and the fourhorn sculpin. Some of these relicts are derived from glacial lakes, such as "Monoporeia affinis", which is a main element in the benthic fauna of the low-salinity Bothnian Bay.
Cetaceans in the Baltic Sea are monitored by the countries bordering the sea and data compiled by various intergovernmental bodies, such as ASCOBANS. A critically endangered population of harbor porpoise inhabit the Baltic proper, whereas the species is abundant in the outer Baltic (Western Baltic and Danish straits) and occasionally oceanic and out-of-range species such as minke whales, bottlenose dolphins, beluga whales, orcas, and beaked whales visit the waters. In recent years, very small, but with increasing rates, fin whales and humpback whales migrate into Baltic sea including mother and calf pair. Now extinct Atlantic grey whales (remains found from Gräsö along Bothnian Sea/southern Bothnian Gulf and Ystad) and eastern population of North Atlantic right whales that is facing functional extinction once migrated into Baltic Sea.
Other notable megafauna include the basking sharks.
Environmental status.
Satellite images taken in July 2010 revealed a massive algal bloom covering in the Baltic Sea. The area of the bloom extended from Germany and Poland to Finland. Researchers of the phenomenon have indicated that algal blooms have occurred every summer for decades. Fertilizer runoff from surrounding agricultural land has exacerbated the problem and led to increased eutrophication.
Approximately of the Baltic's seafloor (a quarter of its 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 neighboring Atlantic.
Plans to artificially oxygenate areas of the Baltic that have experienced eutrophication have been proposed by the University of Gothenburg and Inocean AB. The proposal intends to use wind-driven pumps to pump oxygen-rich surface water to a depth of around 130 m.
After World War II, Germany had to be disarmed and large quantities of ammunition stockpiles were disposed directly into the Baltic Sea and the North Sea. Environmental experts and marine biologists warn that these ammunition dumps pose an environmental threat with potentially life-threatening consequences to the health and safety of humans on the coastlines of these seas.
Future change.
Climate change, and pollution from agriculture and forestry, impose such strong effects on the ecosystems of the Baltic sea, that there is a concern the sea will turn from a carbon sink to a source of CO2 and methane. Modelling climate change and the impact of well characterised factors such as post-glacial rebound before the year 2050, is complicated by the unique properties of the Baltic Sea area compared to say the adjacent North Sea and controversy as to the relative contributions of socio-economic factors such as land use to any warming component.537 These include its current brackish water, the southern subbasin tendency to have a vertical stratification of the halocline, and the northern subbasin seasonal sea ice cover.458 High confidence future projections include: air temperature warming, more heavy precipitation episodes, less snow with less perifrost and glacial ice mass in northern catchment areas, more mild winters, raised mean water temperature with more marine heatwaves, intensified seasonal thermoclines without change in the thermohaline circulation, and sea level rise. There are many more projections but these have lower confidence.
Economy.
Construction of the Great Belt Bridge in Denmark (completed 1997) and the Øresund Bridge-Tunnel (completed 1999), linking Denmark with Sweden, provided a highway and railroad connection between Sweden and the Danish mainland (the Jutland Peninsula, precisely the Zealand). The undersea tunnel of the Øresund Bridge-Tunnel provides for navigation of large ships into and out of the Baltic Sea. The Baltic Sea is the main trade route for the export of Russian petroleum. Countries neighboring the Baltic Sea have expressed concerns about this since a major oil leak in a seagoing tanker would be especially disastrous for the Baltic given the slow exchange of water in the ecosystem. The tourism industry surrounding the Baltic Sea is naturally concerned about oil pollution.
Much shipbuilding is carried out in the shipyards around the Baltic Sea. The largest shipyards are at Gdańsk, Gdynia, and Szczecin, Poland; Kiel, Germany; Karlskrona and Malmö, Sweden; Rauma, Turku, and Helsinki, Finland; Riga, Ventspils, and Liepāja, Latvia; Klaipėda, Lithuania; and Saint Petersburg, Russia.
There are several cargo and passenger ferries that operate on the Baltic Sea, such as
Construction of the Fehmarn Belt Fixed Link between Denmark and Germany is due to finish in 2029. It will be a three-bore tunnel carrying four motorway lanes and two rail tracks.
Through the development of offshore wind power the Baltic Sea is expected to become a major source of energy for countries in the region. According to the Marienborg Declaration, signed in 2022, all EU Baltic Sea states have announced their intentions to have 19.6 gigawatts of offshore wind in operation by 2030.
Tourism.
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The Helsinki Convention.
1974 Convention.
For the first time ever, all the sources of pollution around an entire sea were made subject to a single convention, signed in 1974 by the then seven Baltic coastal states. The 1974 Convention entered into force on 3 May 1980.
1992 Convention.
In the light of political changes and developments in international environmental and maritime law, a new convention was signed in 1992 by all the states bordering on the Baltic Sea, and the European Community. After ratification, the Convention entered into force on 17 January 2000. The Convention covers the whole of the Baltic Sea area, including inland waters and the water of the sea itself, as well as the seabed. Measures are also taken in the whole catchment area of the Baltic Sea to reduce land-based pollution. The convention on the Protection of the Marine Environment of the Baltic Sea Area, 1992, entered into force on 17 January 2000.
The governing body of the convention is the Helsinki Commission, also known as HELCOM, or Baltic Marine Environment Protection Commission. The present contracting parties are Denmark, Estonia, the European Community, Finland, Germany, Latvia, Lithuania, Poland, Russia, and Sweden.
The ratification instruments were deposited by the European Community, Germany, Latvia and Sweden in 1994, by Estonia and Finland in 1995, by Denmark in 1996, by Lithuania in 1997, and by Poland and Russia in November 1999.
See also.
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Notes.
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References.
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Battle of Karuse
1270 battle of the Livonian Crusade on the frozen Baltic Sea near Muhu Island
The Battle of Karuse or Battle on the Ice was fought on 16 February 1270 between the Grand Duchy of Lithuania and the Livonian Order on the frozen Baltic Sea between the island of Muhu and the mainland. The Lithuanians achieved a decisive victory. The battle, named after the village of Karuse, was the fifth-largest defeat of the Livonian or Teutonic Orders in the 13th century. Almost all that is known about the battle comes from the "Livonian Rhymed Chronicle", which devoted 192 lines to the battle.
Background.
The Livonian Brothers of the Sword, a crusading military order established in 1202, set out to conquer and convert to Christianity indigenous peoples of present-day Latvia and Estonia. They subjugated the Semigallians by 1250. However, after the Livonian defeats in the 1259 Battle of Skuodas and the 1260 Battle of Durbe, the Semigallians rebelled. Traidenis, who became Grand Duke of Lithuania in 1269 or 1270, supported the rebellion.
In winter 1270, the Livonian Order invaded Semigalia. However, after learning that a large Lithuanian army had also invaded the region, Master Otto von Lutterberg decided to retreat to Riga. The Lithuanians marched north, reaching as far as the island of Saaremaa, which they were able to reach because the Baltic Sea was frozen. The Lithuanian army plundered the area, taking much war loot. It is unclear whether Semigallians joined the Lithuanians and participated in this campaign – contemporary sources do not mention them, but later sources such as "Jüngere Hochmeisterchronik" and Dionysius Fabricius always mention their participation.
Master Lutterberg gathered a large army of Livonian knights, soldiers from the Bishopric of Dorpat, the Bishopric of Ösel–Wiek, Danish Estonia, as well as local tribes of Livs and Latgalians. The Order was well-prepared for the battle: for a year it had been recruiting soldiers for an expedition into Semigalia. The Livonian army marched north to meet the Lithuanians near Saaremaa Island. The armies met on the frozen Moon Sound (probably near Virtsu) on the feast day of Juliana of Nicomedia.
Battle.
The Livonian army positioned for the battle: troops from Danish Estonia, commanded by the Danish king's viceroy Siverith, formed the right flank; Livonian knights, commanded by Master Luttenberg, formed the center; soldiers from the Bishoprics formed the left flank. The Lithuanians arranged their sleighs as a barricade. A vanguard unit likely covered construction of the improvised barricade so that the knights could not see it. When the knights attacked, Lithuanians retreated behind their sleighs and the Livonian cavalry ran into the barricade. As the horses got stuck between the sleighs, the horses and their riders were struck by Lithuanian spears. A small number of Livonian knights managed to break through the barricade and the left and right flanks joined the fighting, but that was not enough to overcome the strong Lithuanian formation. The Lithuanians achieved a decisive victory: 52 knights, including Master Lutterberg, and some 600 low-ranking soldiers were killed while bishop Hermann of Ösel-Wiek was gravely injured and barely managed to escape. According to the Livonian Rhymed Chronicle, 1600 Lithuanians were killed, but that information is very doubtful and most likely inflated by pro-Livonian bias.
Aftermath.
Vice-Master Andreas von Westfalen, who acted as a Master before proper elections could be held, decided to restore the lost morale of the knights by winning a quick victory. In the middle of 1270 he learned of another Lithuanian raid into Livonia and hurried his soldiers to seek out the enemy. While the knights were resting, the Lithuanians attacked their camp and killed Andreas and twenty more knights. This is sometimes known as the Battle of Pārdaugava near Riga, and was the tenth-largest defeat of the Teutonic Knights in its own right. Traidenis scored another victory in 1279 during the Battle of Aizkraukle.
References.
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Battle of Kars
1877 Russian victory over the Ottoman Empire
The Battle of Kars was a Russian victory over the Ottoman Empire during the Russo-Turkish War (1877–1878). The battle for the city took place on November 17, 1877, and resulted in the Russians capturing the city along with a large portion of the Ottoman forces defending the city. Although the actual battle for the city lasted a single night, fighting for the city began in the summer of that year. The idea of taking the city was considered impossible by some in Russian high command and many soldiers, who thought it would lead to needlessly high Russian casualties without any hopes of success due to the strength of the Ottoman position. Loris Melikov and others among the Russian command, however, devised a plan of attack that saw Russian forces conquer the city after a night of long and hard fighting. The Ottoman defeat at Kars had widespread consequences regionally, and the city was formally annexed at the Treaty of Berlin.
Battles in the build up to the attack.
The start to the successful Russian attack of the city of Kars began in early October with fighting in the surrounding areas around Kars. Fighting in October 1877 began with the Russians advancing on the hills of Little Yahni on October 2, and Great Yahni on October 3. Although the Russians experienced success in regards to Great Yahni, the Ottoman forces garrisoning Little Yahni were putting up a fierce resistance, and by October 4, General Loris Melikov called off his attack of the hill. Despite their success on Great Yahni, the Russians had already suffered 5,000 casualties and their soldiers were exhausted after near constant fighting and marching for two to three days straight. At this point, the Ottoman army had amassed nearly 5,000 casualties. For a short period there was peace on the front, with the Turkish forces retreating to the fortified positions of Alaca-Dag on the 8th. By the 14th of October, fighting had resumed with the commence of a Russian flanking maneuver led by General Lazarev. He fielded as much as 11,000 men for the attack, including 2,500 sabres and 72 guns, in opposition to about 10,000 Ottoman men tasked with the defense of a frontline spanning nearly 15 miles long. The result of the battle was the rout of Ahmet Muhtar’s army on the 15th. The Ottoman general amassed 6,000 casualties in comparison to the 1,500 casualties the Russians suffered.
The storming of Kars.
After the successes in the battles in the area surrounding the city, the Russian high command began their plans for the attack on the city of Kars. The Ottoman garrison guarding the city consisted of 18,000 infantry as well as 5,000 artillery. The Russian army, on the other hand, involved 30,000 infantry and 144 guns in the attack. Despite the numerical superiority, French attaché General de Courcy, who was advising the Russians, declared the fortress impregnable and that any attack would lead to countless Russian casualties. His opinion was shared by many in the high command as well as the majority of the troops. The city was well defended, and an all-out assault would likely lead to enormous Russian casualties as General de Courcy suggested. The Russian high command, however, planned a night attack that involved careful preparation for two weeks prior and simultaneous attacks along a stretched enemy line. The first part the Russian attack was a heavy bombardment of the cities defenses and suburbs in the weeks leading up to the actual assault, with the goal of demoralizing the civilian population that already yearned for capitulation. The Russians began their assault on the city at 9 pm on November 17 with simultaneous attacks on several points along the city. The complete surprise of the attack, as well as the demoralized and under equipped Ottoman forces defending the city, meant that after intense fighting throughout the night, the city fell the next day. The Russians captured 17,000 prisoners, with 4,500 of those being sick and wounded in the hospitals. The Ottoman fighting forces additionally lost 2,500 soldiers, and the Russians amassed 2,196 casualties.
Aftermath of the Battle of Kars.
The Russian success at the Battle of Kars largely wrapped up the Caucasian front of the Russo-Turkish war of 1877-1878. The city, along with surrounding territory governed by the Ottoman Empire up to that point, was ceded to the Russian empire after the Treaty of Berlin. The following years saw a significant amount of Armenians immigrate from the Ottoman Empire into Russian Transcaucasia, as well as Muslim Turks and Kurds immigrate from the newly annexed Russian territory into Ottoman lands.
Legacy.
In 1880, Russian composer Modest Mussorgsky wrote a triumphal march named "The Capture of Kars" in honor of the victory.
References.
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Battle of Karasu
The First Battle of Karasu was a battle that occurred during the Russian–Turkish War of 1768-1774, which took place during the Russian army's campaign in Wallachia and Rumelia.
Prelude.
There were differences between Ekaterina II and P. A. Rumyantsev regarding the plan for the 1773 campaign on the Danube. The Empress proposed to go on the offensive, defeat the Turks and push them back to Balkans. The commander of the 1st Army defended the former tactics of raids by small detachments. Under pressure from the empress, he had to adopt the option of more active operations beyond the Danube. The first object of the onslaught, according to the plan, was the fortress Silistria. The advance of the main forces was to be facilitated by the actions (searches) of the detachments of O. A. Weismann and I. P. Saltykov on the right bank of the Danube.
Weismann crossed the Danube, and on May 26 his detachment (6,500 men with 38 guns) assembled at Karamurat. Turkish camp at Karasu was covered on the north side of the bay and two ramparts of old earthen fortifications; on the isthmus formed by the bay, a battery was built. Due to the difficulty of attacking from the front, Weismann decided to bypass the position from the right flank, from where the Turkish camp was covered by only one retrenchment.
At 2 a.m. on May 27, Weismann set out from Karamurat. In the vanguard marched Colonel R. F. Leviz. The main forces moved in 2 columns: Weismann himself and Major-General Prince Golitsyn; the artillery followed between the columns. The movement was closed by the rearguard of Premier Major-General Glebov (500 men and 4 guns).
Battle.
At 5 a.m. the detachment approached the tip of Karasu Bay. The Turks sent some cavalry to meet them, which after a skirmish fled to their main forces on the heights to the south. Leviz moved Cossacks and karabiner, but the Turks retreated without a fight, partly to Karasu, partly to Usman-Faki.
Weisman ordered Levis to continue moving towards Karasu, but not to do anything decisive until the arrival of the main forces. Following on, Levis overturned the Turkish cavalry on the offensive and approached the eastern retrenchment. The enemy cavalry, turning to the left, in a gully, opened the retrenchment, whence began a cannonade on the vanguard, confusing it. This was taken advantage of by the Turkish cavalry, which attacked the left flank and forced the Russian cavalry to fall back on their infantry, who stopped the Turks with rifle fire and gave the cavalry an opportunity to regain their ranks.
At this time the main force was approaching the battle site. Weismann ordered the artillery to shell the retrenchment and then moved the infantry to attack. The Turks did not wait for the Russian approach and, leaving the camp and the retrenchment, began at 8 o'clock to retreat along the road to Bazardzhik. Russian cavalry pursued the retreating enemy for 10 versts. The Turks lost up to 1,200 killed, 104 prisoners and 16 cannon, the entire camp and wagon; the Russians lost 58 killed and 121 wounded.
References.
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Ust-Izhora
Municipality in the Kolpinsky district of St. Petersburg, Russia
Ust-Izhora () is a municipal settlement in Kolpinsky District of the federal city of St. Petersburg, Russia, situated at the confluence of the Izhora and Neva Rivers, and is roughly equidistant to St. Petersburg and Shlisselburg, Russia, from both the Gulf of Finland in the west and Lake Ladoga in the northeast. Population:  (2010 Census);  (2002 Census);  (1989 Soviet census)
The settlement is believed to mark the location of the Battle of the Neva (July 15, 1240), when weak forces led by Prince Alexander Yaroslavich of Novgorod defeated the Swedes here, and prevented them from advancing farther south into Ingria. The chronicles tell of a "great battle," in which Alexander's men stormed and sank three Swedish ships, and Alexander himself wounded Birger, the Swedish commander.
Following this victory on the Neva, the prince was renamed Alexander Nevsky. The Russian Orthodox Church eventually canonized him, and he is now the patron saint of Saint Petersburg. A church was built on the bank of the Neva in 1799 to commemorate the famous battle. Close by the church are two monuments honoring Alexander Nevsky, in whose memory the church is dedicated.
References.
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Siege of Kars (1828)
1828 battle of the Russo-Turkish War (1828–1829)
The siege of Kars took place during the Russo-Turkish War of 1828–1829. A Russian army, led by General Ivan Paskevich, successfully took Kars in Turkish Armenia from the Ottomans. The battle itself lasted three days, from 20 to 23 June 1828. The capture was almost a complete accident. During the initial stages of the war, a rifleman enacted an unauthorized advancement towards the city and with the Russian army noticing the imminent danger said troop was in, they rushed to their protection which thus resulted in Kars falling after Ottoman troops engaged the Russian position. The Ottoman force, numbering some 11,000 men before the siege, lost 2,000 men and 151 artillery guns. The Russian contingent lost 400 men.
References.
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Karelian Isthmus
Isthmus in North-Western Russia
The Karelian Isthmus (; ; ) is the approximately stretch of land situated between the Gulf of Finland and Lake Ladoga in northwestern Russia, to the north of the River Neva. Its northwestern boundary is a line from the Bay of Vyborg to the westernmost point of Lake Ladoga, Pekonlahti. If the Karelian Isthmus is defined as the entire territory of present-day Saint Petersburg and Leningrad Oblast to the north of the Neva and also a tiny part of the Republic of Karelia, the area of the isthmus is about .
The smaller part of the isthmus to the southeast of the old Russia-Finland border is considered historically as Northern Ingria, rather than part of the Karelian Isthmus itself. The rest of the isthmus was historically a part of Finnish Karelia. This was conquered by the Russian Empire during the Great Northern War in 1712 and included within the autonomous Grand Duchy of Finland (1809–1917) of the Russian Empire. When Finland became independent in 1917, the isthmus (except for the territory roughly corresponding to present-day Vsevolozhsky District and some districts of Saint Petersburg) remained Finnish. Finnish Karelia was partly ceded to the Soviet Union by Finland following the Winter War (1939–1940) and Continuation War (1941–1944). In 1940–1941, during the Interim Peace, most of the ceded territories in the isthmus were included within the Karelo-Finnish SSR. However, since World War II the entire isthmus has been divided between the city of Saint Petersburg (mostly Kurortny District), as well as Priozersky District, Vsevolozhsky District and Vyborgsky District of Leningrad Oblast.
According to the 2002 census, the population of the Kurortny District of Saint Petersburg and the parts of Leningrad Oblast situated on the Karelian Isthmus amounts to 539,000. Many Saint Petersburg residents also decamp to the Isthmus during their vacations. The main population centers of the Isthmus are Vyborg ("Выборг"; ; ), Priozersk ("Приозе́рск"; ; ) and Primorsk ("Примо́рск"; ; ).
Geography and wildlife.
The isthmus' terrain has been influenced dramatically by the Weichselian glaciation. Its highest point lies on the Lembolovo Heights moraine at about 205 m (670 ft). There are no mountains on the isthmus, but steep hills occur in some places.
The Vuoksi, the largest river, runs southeastwards from Lake Saimaa of Finland to Lake Ladoga, dividing the isthmus into two uneven parts. Saimaa Canal opened in 1856 links Lake Saimaa to the Bay of Vyborg passing through the city of Lappeenranta in South Karelia, Finland.
The Karelian Isthmus lies within the ecoregion of Scandinavian and Russian taiga. Geobotanically, it lies at the juncture of the Central European, Eastern European and Northern European floristic provinces of the Circumboreal Region of the Holarctic Kingdom.
The isthmus is mostly covered by coniferous forests formed by Scots pine ("Pinus sylvestris") and Norway spruce ("Picea abies"), with numerous lakes (e.g. Lake Sukhodolskoye and Lake Glubokoye) as well as small grass, fen and "Sphagnum" raised bogs. Forests cover approximately 11,700 km of the isthmus, more than three quarters of its total area. Swampy areas occupy 5.5 percent of the territory. In the large contiguous area along the shore of Lake Ladoga in Vsevolozhsky District, in the southeastern part of the isthmus, bogs occur much more frequently than in other parts. The same was once true of the lowland along the Neva River, which has since been drained. The soil is predominantly podsol, which contains massive boulders, especially in the north and northwest, where large granite rocky outcrops occur.
Pine forests (with "Pinus sylvestris") are the most widespread and occupy 51% of the forested area of the Karelian Isthmus, followed by spruce forests (with "Picea abies", 29%) and birch forests (with "Betula pendula" and "B. pubescens", 16%). Stands on more fertile soils and in more favorable locations are occasionally dominated by Norway maple, black alder, grey alder, common aspen, English oak, grey willow, dark-leaved willow, tea-leaved willow, small-leaved lime or European white elm. Common vegetation of various types of pine forests includes heather, crowberry, common juniper, eared willow, lingonberry, water horsetail, bracken, graminoids (i.e. grasses in the wider sense) "Avenella flexuosa" and "Carex globularis", mosses "Pleurozium schreberi", "Sphagnum angustifolium" and "S. russowii", and lichens "Cladonia" spp. Prominent in various spruce forests are wood horsetail, common wood sorrel, bilberry, lingonberry, graminoids "Avenella flexuosa", "Calamagrostis arundinacea", "Carex globularis", and mosses "Polytrichum commune" and "Sphagnum girgensohnii". Prominent vegetation of various birch forests include meadowsweet, common wood sorrel, bilberry and graminoids "Calamagrostis arundinacea" and "C. canescens".
1184 species of wild vascular plants are recorded in the isthmus. See also the List of the vascular plants of the Karelian Isthmus. Red squirrel, moose, red fox, mountain hare and boar (reintroduced) are typical inhabitants of the forests.
The climate of the isthmus is moderately continental, with 650–800 mm (25–32 in) average precipitation per year, long snowy winters lasting from November through mid-April and occasionally reaching about -40 °C (-40 F), moderately cool summers and short frost-free period. Compared to other parts of the Leningrad Oblast, the winter here is usually milder due to the moderating influence of the Gulf of Finland, but longer.
The city of Vyborg and the town of Priozersk are situated on the northwestern part of the isthmus.
The Karelian Isthmus is a popular place for hiking, cycling, skiing (Korobitsyno and Kavgolovo), climbing (near Kuznechnoye), canoeing (Losevo), fishing for consumption (of carp bream, northern pike, roach, European perch, ruffe, burbot and others), mushroom hunting (for porcini, red-capped scaber stalk, birch bolete, velvet bolete, slippery Jack, golden chanterelle, "Lactarius resimus", woolly milk-cap, ugly milk-cap, saffron milk-cap, "Lactarius rufus", various Russulas and others), berry picking (of bilberry, raspberry, woodland strawberry, cowberry, cranberry, cloudberry, bog bilberry and stone bramble). It is a popular summer resort for Saint Petersburg citizens since the late 19th century, served by trains of Finlyandsky Rail Terminal. The isthmus, especially the land along Saint Petersburg–Vyborg and Saint Petersburg–Priozersk railroads, hosts numerous dachas.
A 20–35 km wide stretch of land in Vyborgsky District and Republic of Karelia to the west of the Vyborg–Hiitola railway, as well as the islands and shores of the Gulf of Vyborg, belongs to the strictly guarded zone of the border control, reaching the shore of Lake Ladoga at Hiitola. In 1993–2006 the zone was formally 5 km wide, although in fact it has always been much wider. Visiting it is forbidden without a permit issued by the FSB (by KGB during the time of the Soviet Union).
Geological history.
Geologically the Karelian Isthmus lies on the southern edge of the Baltic Shield's crystalline bedrock. During the final part of the last Weichselian glaciation, deglaciation in the central parts of the Isthmus started as early as 14000 BP, when it formed the bottom of a large lake dammed by the surrounding ice sheet. During further deglaciation, at the time of the Baltic Ice Lake, an early high water stage of the Baltic Sea, when the ice sheet retreated to Salpausselkä, the upland area of the Isthmus remained a large island and many upland lakes emerged.
Prior to 12650 BP, the land was characterized by harsh Arctic conditions with permafrost and sparse vegetation. Steppe-tundra complexes developed after this point. Around 11000 BP climate began to warm and became humid, first pine and birch forests were established.
Around 9000 BP Ancylus Lake, another stage of the Baltic Sea, retreated, and many lowland lakes were also isolated in depressions formed earlier by glacial exaration and fluvioglacial activity. Lake Ladoga was separated from the sea as well. Due to land uplift, around 5000 BP the River Vuoksi started emptying into Lake Ladoga as a new outlet of Lake Saimaa. Lake Ladoga transgressed, flooding lowland lakes and the Vuoksi, and became connected with the sea at Heinjoki (now Veshchevo), to the east of present-day Vyborg. Around 3100–2400 BP the Neva River emerged, draining Lake Ladoga into the Baltic Sea. Ladoga level gradually sank from 15–18 m to its modern position of 4–5 m above sea-level, and lowland lakes were isolated again. However, the Vuoksi still had a significant direct outflow connection to the Bay of Vyborg, possibly as late as in the 12th century AD. The connection disappeared due to ongoing land uplift in the 2nd millennium AD.
In 1818 a canal, which was dug to drain spring flood waters from Lake Suvanto (now Lake Sukhodolskoye, a 40-km long narrow lake in the eastern part of the Isthmus) into Lake Ladoga, unexpectedly eroded and turned into the Taipaleenjoki (now Burnaya River). The Taipaleenjoki started draining Suvanto and decreased its level by 7 m. Originally waters of Lake Suvanto flowed into the Vuoksi River through a waterway at Kiviniemi (now Losevo), but as a result of the change, the waterway dried out. In 1857 the canal was dug there, but the stream reversed direction, revealed rapids and rendered navigation at Kiviniemi impossible. Since 1857 Suvanto and the Taipaleenjoki have constituted the southern armlet of the Vuoksi River, which has decreased the level of the original northern armlet emptying into Ladoga near Kexholm (now Priozersk) by 4 m, isolating it as a separate river basin.
Cities, towns and urban-type settlements.
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Name in Swedish added when it differs from the Finnish.
Kamennogorsk () ()
Kuznechnoye ("Kaarlahti")
Lesogorsky ("Jääski") )
Primorsk ("Koivisto") )
Priozersk ("Käkisalmi") )
Roshchino ("Raivola")
Saint Petersburg ("Pietari") )
Sertolovo ("Sierattala")
Sestroretsk ("Siestarjoki") )
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