BALTIC SEA (late Latin - Mare Balticum, among the ancient Slavs - Varangian Sea or Sveiskoe), inland sea Atlantic Ocean, between the Scandinavian Peninsula and the mainland shores of Northwestern Europe. It washes the shores of Sweden, Finland, Russia, Estonia, Latvia, Lithuania, Poland, Germany, Denmark. In the southwest it connects with North Sea Danish Straits. Maritime border Baltic Sea passes along the southern entrances of the Oresund, Great Belt and Little Belt straits. Area 419 thousand km 2, volume 21.5 thousand km 3. The greatest depth is 470 m. Depths above the rapids of the Danish Straits: Darser - 18 m, Drogden - 7 m. The cross section above the rapids is 0.225 and 0.08 km 2, respectively, which limits water exchange with the North Sea. The Baltic Sea juts deep into the Eurasian continent. The heavily indented coastline forms numerous bays and bays. The largest bays are: the Gulf of Bothnia, the Gulf of Finland, the Gulf of Riga, the Curonian Lagoon, the Szczecin Bay, the Gulf of Gdansk. The shores of the Baltic Sea in the north are high, rocky, mainly of skerry and fjord types, in the south and southeast they are mostly low-lying, lagoon-type, with sandy and pebble beaches. The largest islands: Gotland, Bornholm, Saaremaa, Muhu, Hiiumaa, Öland, Rügen. There are many small rocky islands - skerries, located along the northern shores (there are over 6 thousand in the Åland group of islands).

Relief and geological structure bottom. The Baltic Sea is shallow, lies entirely within the shelf, depths up to 200 m occupy 99.8% of its area. The shallowest waters are the Gulf of Finland, the Gulf of Bothnia and the Gulf of Riga. These areas of the bottom have a leveled accumulative topography and a well-developed cover of loose sediments. Most of the bottom of the Baltic Sea is characterized by highly dissected relief. The bottom of its basin has depressions delimited by hills and the bases of islands: in the west - Bornholm (105 m) and Arkon (53 m), in the center - Gotland (249 m) and Gdansk (116 m); to the north of the island of Gotland, the deepest depression, the Landsort depression (up to 470 m), stretches from northeast to southwest. Numerous stone ridges, in the central part of the sea ledges are traced - continuations of cliffs stretching from the northern coast of Estonia to the northern tip of the island of Öland, underwater valleys, glacial-accumulative landforms flooded by the sea.

The Baltic Sea occupies a depression in the west of the ancient East European Platform. The northern part of the sea is located on the southern slope of the Baltic Shield; the central and southern parts belong to a large negative structure of the ancient platform - the Baltic syneclise. The extreme southwestern part of the sea is part of the young Western European Platform. The bottom in the north of the Baltic Sea is composed mainly of complexes of Precambrian age, overlain by an intermittent cover of glacial and modern marine sediments. In the central part of the sea, Silurian and Devonian sediments take part in the structure of the bottom. The ledges traced here are formed by Cambrian-Ordovician and Silurian rocks. Paleozoic complexes in the south are overlain by thick layers of glacial and marine sediments.

During the last ice age (late Pleistocene), the Baltic Sea basin was completely blocked by an ice sheet, after the melting of which the Baltic Glacial Lake was formed. At the end of the Late Pleistocene, about 13 thousand years ago, the lake connected with the ocean, and the depression was filled with sea water. The connection with the ocean was interrupted in the interval 9-7.5 thousand years ago, after which a marine transgression followed, the deposits of which are known on the modern coast of the Baltic Sea. In the northern part of the Baltic Sea, the rise continues, the speed of which reaches 1 cm per year.

Bottom sediments at depths of over 80 m are represented by clayey silts, under which lies banded clay on glacial deposits; at shallower depths, silt is mixed with sand; sand is common in coastal areas. There are boulders of glacial origin.

Climate. The Baltic Sea is characterized by a temperate maritime climate with continental features. Its seasonal features are determined by the interaction of pressure centers: the Icelandic minimum and the Azores maximum in the west and the Siberian maximum in the east. Cyclonic activity reaches its greatest intensity in the autumn-winter months, when cyclones bring cloudy, rainy weather with strong westerly and south-westerly winds. The average air temperature in February ranges from -1.1°C in the south, -3°C in the central part of the sea, to -8°C in the north and east, in the northern part of the Gulf of Bothnia to -10°C. Rarely and for a short time, cold Arctic air penetrating the Baltic Sea lowers the temperature to -35°C. In summer, westerly winds also blow, but with little strength, bringing cool, humid weather from the Atlantic. The air temperature in July is 14-15°C in the Gulf of Bothnia and 16-18°C in other areas of the sea. Rare arrivals of warm Mediterranean air cause short-term increases in temperature to 22-24°C. The annual precipitation ranges from 400 mm in the north to 800 mm in the south. The largest number of days with fog (up to 59 days per year) is observed in the south and central part of the Baltic Sea, the smallest (22 days per year) - in the north of the Gulf of Bothnia.

Hydrological regime. The hydrological conditions of the Baltic Sea are determined by its climate, significant influx of fresh water and limited water exchange with the North Sea. About 250 rivers flow into the Baltic Sea. The average river flow is 472 km 3 per year. Most large rivers: Neva - 83.5 km 3, Vistula - 30, Neman - 21, Western Dvina- 20 km 3 per year. Freshwater flow is distributed unevenly across the territory. The Gulf of Bothnia receives 181, the Gulf of Finland - 110, the Gulf of Riga - 37, and the central part of the Baltic Sea - 112 km 3 per year. The amount of fresh water entering with precipitation (172 km 3 per year) is equal to evaporation. Water exchange with the North Sea averages 1,660 km 3 per year. Fresher waters with surface runoff flow leave the Baltic Sea into the North Sea, salty North Sea water with bottom currents enters through the straits from the North Sea. Strong westerly winds usually increase the inflow, while eastern winds increase the outflow of water from the Baltic Sea through the Danish Straits.

The hydrological structure of the Baltic Sea in most areas is represented by surface and deep water masses, separated by a thin intermediate layer. The surface water mass occupies a layer from 20 to (in some places) 90 m, its temperature throughout the year ranges from 0 to 20 ° C, salinity is usually within 7-8‰. This water mass is formed in the sea itself as a result of the interaction of sea waters with fresh waters from atmospheric precipitation and river runoff. It has winter and summer modifications, differing mainly in temperature. In the warm season, the presence of a cold intermediate layer is noted, which is associated with the summer heating of water on the surface. The deep water mass occupies a layer from 50-100 m to the bottom, its temperature varies from 1 to 15 ° C, salinity - from 10.0 to 18.5‰. Deep water is formed in the bottom layer as a result of mixing with high salinity water coming from the North Sea. Renewal and ventilation of bottom waters strongly depend on the flow of north sea ​​water, which is subject to interannual variability. With a reduction in the influx of salt water into the Baltic Sea at great depths and in depressions in the bottom topography, conditions are created for the occurrence of dead water phenomena. Seasonal changes in water temperature affect the layer from the surface to 50-60 m and usually do not penetrate deeper.

Wind waves develop especially strongly in autumn-winter with long and strong south-west winds, when waves 5-6 m high and 50-70 m long are observed. The highest waves are observed in November. In winter, sea ice prevents the development of waves.

In the Baltic Sea, cyclonic (counterclockwise) water circulation, complicated by vortex formations of different scales, can be traced everywhere. The speed of constant currents is usually about 3-4 cm/s, but in some areas they sometimes increase to 10-15 cm/s. Due to low speeds, currents are unstable, their pattern is often disrupted by winds. Storm winds cause strong wind currents with speeds of up to 150 cm/s, which quickly fade after the storm.

The tides in the Baltic Sea, due to the insignificant connection with the ocean, are weakly expressed, the height is 0.1-0.2 m. Surge level fluctuations reach significant values ​​(at the tops of the bays up to 2 m). The combined effects of wind and sudden changes in atmospheric pressure cause seiche level fluctuations with a period of 24-26 hours. The magnitude of such fluctuations is from 0.3 m in the open sea to 1.5 m in Gulf of Finland. Seiche waves with surge westerly winds sometimes cause the level at the top of the Gulf of Finland to rise to 3-4 m, which delays the flow of the Neva and leads to floods in St. Petersburg, sometimes catastrophic: in November 1824 about 410 cm, in September 1924 - 369 cm.

The surface water temperature of the Baltic Sea varies greatly from season to season. In August, in the Gulf of Finland the water warms up to 15-17°C, in the Gulf of Bothnia 9-13°C, in the central part of the sea 14-18°C, in the southern regions it reaches 20°C. In February, in the open part of the sea, the surface water temperature is 1-3°C, in bays and bays it is below 0°C. The salinity of water on the surface is 11‰ at the exit from the Danish Straits, 6-8‰ in the central part of the sea, 2‰ and less at the tops of the Gulf of Bothnia and the Gulf of Finland.

The Baltic Sea belongs to the so-called brackish basins, in which the temperature of the highest density is above the freezing point, which leads to the intensification of the formation process sea ​​ice. Ice formation begins in November in bays and off the coast, and later in the open sea. In severe winters, the ice cover occupies the entire northern part seas and coastal waters of its central and southern parts. The thickness of fast ice (fixed ice) reaches 1 m, drifting ice - from 0.4 to 0.6 m. Ice melting begins at the end of March, spreads from southwest to northeast and ends in June.

History of the study. The first information about the exploration of the Baltic Sea is associated with the Normans. In the middle of the 7th century they penetrated into the Gulf of Bothnia, discovered the Åland Islands, and in the 2nd half of the 7th-8th centuries reached west coast The Baltic states discovered the Moonsund archipelago, first penetrated the Gulf of Riga, and in the 9th and 10th centuries used the coast from the mouth of the Neva to the Bay of Gdansk for trade and pirate activities. Russian hydrographic and cartographic work began in the Gulf of Finland at the beginning of the 18th century. In 1738, F.I. Soimonov published an atlas of the Baltic Sea, compiled from Russian and foreign sources. In the middle of the 18th century, many years of research were carried out by A.I. Nagaev, who compiled a detailed sailing guide for the Baltic Sea. The first deep-sea hydrological studies in the mid-1880s were carried out by S. O. Makarov. Since 1920, hydrological work has been carried out by the Hydrographic Administration of the Navy, the State Hydrological Institute (Leningrad), and since the 2nd half of the 20th century, extensive comprehensive research has been launched under the leadership of the Leningrad (St. Petersburg) branch of the State Oceanographic Institute of the Russian Academy of Sciences.

Economic use. Fish resources consist of freshwater species living in the desalinated waters of the bays (crucian carp, bream, pike, pike perch, chub), the Baltic salmon stock and purely marine species distributed mainly in the central part of the sea (cod, herring, smelt, vendace, sprat). In the Baltic Sea, fishing is carried out for herring, sprat, herring, smelt, flounder, cod, perch, etc. A unique fishing object is eel. Placers of amber are widespread on the coast of the Baltic Sea; mining is carried out near Kaliningrad (Russia). Oil reserves were discovered at the bottom of the sea, and industrial development began. Iron ore is mined off the coast of Finland. The Baltic Sea is of great importance as transport artery. Large volumes of liquid, bulk and general cargo are transported across the Baltic Sea. A significant part of the foreign trade of Denmark, Germany, Poland, Russia, Lithuania, Latvia, Estonia, Finland, and Sweden is carried out through the Baltic Sea.

The cargo turnover is dominated by oil products (from Russian ports and from the Atlantic Ocean), coal (from Poland, Russia), timber (from Finland, Sweden, Russia), pulp and paper (from Sweden and Finland), iron ore (from Sweden); Machinery and equipment also play an important role, the major producers and consumers of which are countries located on the shores and in the Baltic Sea basin. Largest ports Baltic Sea: St. Petersburg, Kaliningrad (Russia), Tallinn (Estonia), Riga (Latvia), Gdansk, Gdynia, Szczecin (Poland), Rostock - Warnemünde, Lübeck, Kiel (Germany), Copenhagen (Denmark), Malmö, Stockholm , Luleå (Sweden), Turku, Helsinki, Kotka (Finland). In the Baltic Sea there are sea passenger and ferry connections: Copenhagen - Malmö, Trelleborg - Sassnitz (train ferries), Nortelje - Turku (car ferry), etc. There are many resort places on the southern and south-eastern coasts.

Ecological state. The Baltic Sea, which has difficult water exchange with the World Ocean (water renewal lasts about 30 years), is surrounded by industrialized countries and is experiencing extremely intense anthropogenic pressure. The main environmental problems are related to the burial of chemical weapons at the bottom of the sea and the discharge of waste water into the sea major cities, run-off of chemical fertilizers used in agriculture, and especially with shipping traffic - one of the most intense in the world (mainly oil tankers). After the Convention for the Protection of the Marine Environment of the Baltic Sea came into force in 1980, the environmental situation improved due to the commissioning of a large number of wastewater treatment plants, a reduction in the use of chemical fertilizers, and monitoring the technical condition of ships. The concentration of toxic substances such as DDT and polychlorinated biphenyl, petroleum carbons has decreased. The dioxin content in Baltic herring is 3 times lower than the maximum permissible concentration, and the gray seal population has recovered. The issue of giving the Baltic Sea the status of a particularly vulnerable sea area is being considered.

Lit.: Terms. Concepts. Reference tables. M., 1980; Hydrometeorological conditions of the shelf zone of the USSR seas. L., 1983. T. 1. Issue. 1: Baltic Sea without bays; Atlantic Ocean. L., 1984; Biological resources Atlantic Ocean. M., 1986; Pushcharovsky Yu. M. Tectonics of the Atlantic with elements of nonlinear geodynamics. M., 1994; Hydrometeorology and hydrochemistry of the seas of the USSR. St. Petersburg, 1994. T. 3. Issue. 2; Zalogin B.S., Kosarev A.N. Seas. M., 1999.

The Baltic Sea is an inland marginal sea of ​​Eurasia, protruding deeply into the mainland. The Baltic Sea is located in northern Europe and belongs to the Atlantic Ocean basin. It is connected to the North Sea by the Öresund (Sund), Greater and Greater Belts, Kattegat and Skagerrak straits. The maritime border of the sea runs along the southern entrances of the Öresund, B. and M. Belta straits. The shores of the Baltic Sea in the South and South-East are predominantly low-lying, sandy, lagoon-type; on the land side there are dunes covered with forest, on the sea side there are sandy and pebble beaches. In the North, the shores are high, rocky, predominantly of the skerry type. The coastline is heavily indented and forms numerous bays and bays. The largest bays are: Bothnian (according to physical and geographical conditions, it is a sea), Finnish, Riga, Curonian, Gdansk Bay, Szczecin, etc.

Bottom relief

The Baltic Sea lies within the continental shelf. Average depth sea ​​51 meters. In areas of shallows, banks, and near islands, shallow depths are observed (up to 12 meters). There are several basins in which depths reach 200 meters. The deepest basin is the Landsort basin with a maximum sea depth of 470 meters. In the Gulf of Bothnia the maximum depth is 254 meters, in the Gotland Basin - 249 meters. The bottom in the southern part of the sea is flat, in the north it is uneven and rocky. In coastal areas, sands are common among bottom sediments, but most of the seabed is covered with deposits of clayey silt of green, black or brown color of glacial origin.

Hydrological regime

A special feature of the hydrological regime of the Baltic Sea is a large excess of fresh water, formed due to precipitation and river flow. The brackish surface waters of the Baltic Sea flow through the Danish Straits into the North Sea, and enter the Baltic Sea with the deep current salty waters North Sea. During storms, when the water in the straits is mixed to the very bottom, the water exchange between the seas changes - along the entire cross-section of the straits, water can flow into both the North and Baltic Seas. Baltic Sea in March 2000 (NASA) The circulation of surface waters of the sea is directed counterclockwise, although strong winds can disrupt the circulation pattern. Tides in the Baltic Sea are semidiurnal and diurnal, but their magnitude does not exceed 20 centimeters. Of greater importance are surge phenomena - fluctuations in sea level, which can reach 50 centimeters off the coast, and 2 meters at the tops of bays and bays. At the top of the Gulf of Finland, in some meteorological situations, level rises of up to 5 meters are possible. The annual amplitude of sea level fluctuations can reach 3.6 meters near Kronstadt, and 1.5 meters near Ventspils. The amplitude of seiche vibrations usually does not exceed 50 centimeters.

Compared to other seas, the waves in the Baltic Sea are insignificant. In the center of the sea there are waves up to 3.5 meters high, sometimes higher than 4 meters. In shallow bays the wave height does not exceed 3 meters, but they are steeper. However, it is not uncommon for cases of formation big waves, more than 10 meters high, in conditions where storm winds form waves moving from deep water to shallow water. For example, in the area of ​​the Elands-Sedra-Grunt bank, a wave height of 11 meters was instrumentally recorded. The low salinity of the surface layer contributes to a rapid change in the state of the sea. In winter sailing conditions, ships are at risk of icing. These features of the Baltic, along with a high level of shipping and a large number of navigational hazards, make navigation in this sea a difficult task. Water transparency decreases from the center of the sea to its shores. The clearest water is in the center of the sea and the Gulf of Bothnia, where the water is bluish-green. In coastal areas, the color of the water is yellow-green, sometimes brownish. The lowest transparency is observed in summer due to the development of plankton. sea ​​ice appears first in the bays in October - November. The Bothnian coast and a significant part of the coast (except south coast) The Gulf of Finland is covered with fast ice up to 65 centimeters thick. The central and southern parts of the sea are usually not covered with ice. The ice melts in April, although in the north of the Gulf of Bothnia drift ice can occur in June. Floating bottom ice is common.

Temperature

The temperature of the surface layers of water in summer in the Gulf of Finland is 15-17 °C, in the Gulf of Bothnia - 9-13 °C, in the center of the sea - 14-17 °C. With increasing depth, the temperature slowly drops to the depth of the thermocline (20-40 meters), where there is a sharp jump to 0.2-0.5 °C, then the temperature rises, reaching 4-5 °C at the bottom.

Salinity

The salinity of sea water decreases from the Danish Straits, connecting the Baltic Sea with the salty North Sea, to the east. In the Denmark Straits, salinity is 20 ppm at the surface of the sea and 30 ppm at the bottom. Towards the center of the sea, salinity decreases to 6-8 ppm at the sea surface, in the north of the Gulf of Bothnia it drops to 2-3 ppm, in the Gulf of Finland to 2 ppm. Salinity increases with depth, reaching 13 ppm in the center of the sea near the bottom.

The Baltic Sea and its coast - interesting place, imbued with memories of the Vikings, pacifying with its northern landscapes. It differs from other seas in the nature of its relief, temperature and features. coastline. The Baltic has great historical and geopolitical significance for Russia.

Geographical position

The Baltic Sea on the map is located in northern Europe and belongs to the Atlantic basin. Bounded by latitudes 54°46′ and 65°56′ north and longitudes 9°57′ and 30°00′ east. The extreme points that the Baltic Sea has on the map are: near the Arctic Circle in the north, near Wismar in the south, the eastern point is located near St. Petersburg and the western extreme point is located in the Flensburg area.

Relief and depths

The bottom topography has minor differences from the outlines of the shores bordering the Baltic Sea. Depths, in turn, also depend on the nature of the surrounding area. The southern side of the sea, belonging to Germany, Poland and Denmark, is gentle, level, with sandy beaches. The rocky coast and uneven rocky bottom are in the northern part. The depth and topography of the Baltic Sea varies in different areas. The bottom has a very complex dissected surface. There are depressions that delimit the highlands and bases of the islands that the Baltic Sea includes.

The depths in other places are shallow. For example, there are areas of pronounced accumulative relief - these are the shallow Gulfs of Finland, Riga and Bothnia.

Thus, the Baltic Sea has a depth of less than 200 meters. The Landsort depression is different. Maximum depth The Baltic Sea is located in this section and is about 470 meters. The Landsort depression extends in a southwestern direction. The rest are of lesser depth: Gotland - 249 m and Gdansk - 116 m in the central part of the sea, Arkona - 53 m and Bornholm - 105 m (in the western part).

Sea bays and straits

Refers to inland seas. In the southwest it adjoins the North Sea through the Danish straits (Little and Great Belt, Sound), Skagerrak and Kattegat.

In the east it is located between Estonia and Latvia. The Estonian island of Saaremaa partially separates the bay from the rest of the sea. There are also large Gulfs of Finland and Bothnia

Neva Bay is the eastern part of the Gulf of Finland. At a distance of about 50 km from St. Petersburg, the city of Kronstadt is located. Dam connects island city and St. Petersburg, the highway is laid along a dam, so people have the opportunity to get to the mainland and back by car.

In the northeastern part, where the border between Russia and Finland passes, the Gulf of Finland is connected to the Vyborg Gulf. The Saimaa Canal, leased by Finland, originates there. It serves as a transport route and is also popular with tourists in warm weather. Guests come here for the beauty of the landscapes and duty-free shopping.

Coast

The Baltic Sea coast is diverse. Latvia has accumulation-type shores, formed as a result of the accumulation of sand on the coasts. The lagoon coast, formed by a bay and separated from the sea by a narrow spit, is located near Kaliningrad. The leveled shores border most of the sea, in particular, they belong to Poland. And they are formed under the influence of prevailing winds and coastal currents. Fjords - narrow and deep sea ​​bays with towering steep and rocky shores that surround the sea from the north. They are formed by the flooding of tectonic faults and river valleys. The skerry coast appeared as a result of the flooding of areas with smoothed glaciers composed of crystalline rocks. These hills protrude above the sea surface in the form of many islands-skerries with traces of glacial activity.

The following countries have access to the Baltic Sea: Russia, Latvia, Estonia, Lithuania, Germany, Poland, Sweden, Denmark, Finland. After the collapse of the USSR, Russia was left with a small stretch of coastline, only 7%, instead of the previous 25%, which brings annual losses to the state. Therefore, one port has been established in Primorsk near Vyborg, which will specialize in coal and dry cargo. And the second port is located in Luga Bay, it will be an oil loading port.

Tectonic processes

To this day, the Baltic Sea continues to change. Its depths are shallow compared to other parts of the Atlantic Ocean. Actually, this vast body of water during its existence several times became a lake and again a sea due to tectonic processes.

Currently, the next stage of separation of the sea from the ocean and its transformation into fresh lake. It is characterized by a rise in the bottom of the Gulf of Bothnia by several centimeters per year and flooding southern coasts. Such processes create a need for northern ports to lengthen their piers. To save low-lying parts of the coast, embankments are made.

Temperature layers

The temperature of the Baltic Sea, in turn, depends on the depth. The predominant part of the waters of a huge reservoir can be divided into surface, transitional and deep water masses.

The surface layer ranges from 0 to 20 meters, in places - from 0 to 90 meters with temperatures from 0 to 20 degrees. It is formed as a result of the interaction of the sea with the atmosphere and waters flowing from the mainland. The temperature of the Baltic Sea in this layer varies depending on the time of year. In summer, cold intermediate water masses formed due to significant warming of the sea surface are more pronounced.

The deep layer (bottom and 50-60 meters above it) has a temperature of 1 to 15 degrees. This layer is formed by the flow of water through the Small and Big Belt straits and their mixing.

The transition layer includes water at depths from 20-60 to 90-100 meters. They have a temperature of 2-6 degrees and are formed by mixing waters of deep and surface layers.

Features of water temperature in the Baltic Sea

Certain areas of the sea differ in their water structure. Thus, the Bornholm region has a warm layer (7-11 degrees) both in summer and winter. It is formed by warm waters coming here from the more heated Arkona basin. Due to the shallow depth of the sea and the movement of water in the horizontal plane, there is no cold intermediate layer in summer.

Temperature changes by season

In winter, in the open sea the water temperature is higher than near the coast, while it differs on the western and eastern shores. In February the temperature is 0.7 degrees near Ventspils, in the open sea of ​​the same latitude - approximately 2 degrees, off the western coast - 1 degree.

In summer, surface waters in different parts of the sea also differ in temperature. Prevailing westerly winds drive surface water masses away from the western shores. The underlying cold waters rise to the surface. As a result of this phenomenon in the southern and central regions, and also off the western coasts the temperature is dropping. In addition, there is a cold current from the Gulf of Bothnia to the south along the coast of Sweden.

Seasonal fluctuations in water temperature are pronounced only in the upper 50-60 meters; deeper, the indicators change slightly. There are no changes in temperature during cold times, but with increasing depth the indicators decrease slightly. In warm weather, the water temperature rises to horizons of 20-30 meters due to mixing. Even in summer, when the surface layer of water is warmed up and the thermocline is expressed more sharply than in spring, a cold intermediate layer remains.

The depth, relief and other features of the Baltic Sea depend on many factors. This geographical position, location in northern latitudes, as well as placement on a continental plate.

Baltic Sea(also called the Eastern Sea) is considered an inland sea that extends deep into the continent.

The northern extreme point of the Baltic Sea is located near the Arctic Circle, the southern - near the German city of Wismar, the western - near the city of Flensburg, and the eastern - near St. Petersburg. This sea belongs to the ocean.

General information about the Baltic

The area of ​​the sea (not including islands) is 415 km. sq. It washes the shores of the following states:

• Estonia;
• Russia;
• Lithuania;
• Germany;
• Latvia;
• Poland
• Latvia;
• Denmark;
• Finland;
• * Sweden.

Large bays are considered: Bothnian, Finnish, Riga, Kursk (separated by an oblique). The largest islands: Öland, Wolin, Alandia, Gotland, Als, Saaremaa, Muhu, Men, Usedom, Fore and others. The most big rivers: Trap Dvina, Neva, Vistula, Venta, Narva, Pregolya.

The Baltic Sea, through the Volga-Baltic basin, opens onto and is located on the continental shelf. In the area of ​​islands, shallows and banks, the depth varies within 12 meters. There are a couple of basins where the depth reaches 200 meters. The Landsort Basin is considered the deepest (470 meters), the depth of the basin reaches 250 meters, and in the Gulf of Bothnia - 254 meters.

In the southern region the seabed is flat, and in the north it is predominantly rocky. A huge part of the bottom is covered with sediments of glacial origin of various colors (green, brown, black).

A special feature of the Baltic Sea is that there is an excess of fresh water, which is formed due to river runoff and precipitation.

Its surface brackish waters constantly flow into. During storms, the exchange between these seas changes, as water is mixed from the bottom in the straits. The salinity of the sea is decreasing from the Danish Straits (20 ppm) to the east (in the Gulf of Bothnia it is 3 ppm, and in the Gulf of Finland – 2 ppm). Tides can be diurnal or semidiurnal (do not exceed 20 cm).

When compared with other seas, the disturbances in the Baltic Sea are completely insignificant. In the central parts of the sea, waves can reach 3-3.5 meters, less often - 4 meters. During large storms, waves 10-11 meters high were recorded. The most clear water with a bluish-green tint is observed in the Gulf of Bothnia, in coastal areas it is more turbid and has a yellowish-green color. Due to the development of plankton, the lowest water transparency is observed in summer. The soils of the coastal zone are varied: in the southern regions there is sand, in the east there is silt and sand, and on the northern coast there is stone.

Climate of the Baltic Sea

The sea temperature is generally lower than in other seas. In the mornings in the summer, thanks to the southern winds that drive the upper warm layers into the ocean, the temperature sometimes drops below 12 degrees. When they start to blow north winds, surface waters become significantly warmer. The highest temperature is in August - about 18 C. In January it varies from 0 to 3 C.

Due to its low salinity, harsh winters and shallow depth, the Baltic Sea often freezes, although not every winter.

Flora and fauna

The water in the Baltic Sea changes from sea salt to fresh water. Marine mollusks live only in the western region of the sea, where the water is saltier. Fish here include sprat, cod, and herring. The Gulf of Finland is home to smelt, vendace, salmon and others. Seals live in the area of ​​the Åland Islands.

Due to the presence of many islands, rocks, and reefs in the sea, sailing in the Baltic Sea is quite dangerous. This danger is somewhat reduced due to the presence of a large number of lighthouses here (most of them). The largest cruise ships leave the Danish Straits and enter the Atlantic Ocean. The Great Belt Bridge is considered the most difficult place. The most large ports: Tallinn, Baltiysk, Lubeck, Riga, Stockholm, Szczecin, Rostock, Kiel, Vyborg, Gdansk, St. Petersburg;

• Ptolemy called this sea the Venedian, which comes from the name of the Slavic peoples who lived in ancient times in the southern part of the coast - the Wends or Wends;
• The famous route from the Varangians to the Greeks ran through the Baltic Sea;
• "The Tale of Bygone Years" calls it Varangian Sea;
• The name "Baltic Sea" appears for the first time in the treatise of Adam of Bremen in 1080;
• This sea is rich in oil, manganese, iron and amber. The Nord Stream gas pipeline runs along its bottom;
• Every year on March 22nd the day of protection is celebrated environment Baltic Sea. This decision was made by the Helsinki Commission in 1986.

Resorts

Among the resorts of the Baltic Sea, the most famous are: Zelenogorsk, Svetlogorsk, Zelenogradsk, Pionersky (Russia), Saulkrasti and

Baltic Sea(Old Russian Varangian, Lit./Lat. Baltijos/Baltijas jūra, Liv. Vālda mer, Est. Läänemeri, Finnish. Itämeri, Swiss. Östersjön, Dan. Østersøen, German. Ostsee, Kashubian. Bôłt, Polish. Morze Bałtyckie, Bałtyk, Sami Nuortamearra) inland sea of ​​the Atlantic Ocean. Located off the coast of Northern and Central Europe. It is connected to the North Sea by the Danish Straits. Square- 419 thousand km2, almost equal to the area of ​​the Black Sea (422 thousand km2). The length of the Baltic coastline is 7 thousand km. The northernmost point of the Baltic Sea is located near the Arctic Circle, the southernmost is near Wismar, the westernmost is in the Flensburg area, and the easternmost is in the St. Petersburg area. The coast is distributed between the countries as follows: Sweden owns 35% of the coast, Finland - 17%, the former USSR had 25% of the coast, Russia now has about 7% (approximately 500 km). The rest belongs to Lithuania, Latvia, Estonia, Poland, Germany, Denmark.

Prevailing depths 40-100 m, maximum - 470 m. The greatest depths are in the north, off the coast of Sweden, on average 60-150 m. The Curonian Lagoon is considered the shallowest, where the depths do not exceed 5 meters. In some areas there are underwater shoals, which significantly complicates navigation.

From the history of the Baltic Sea
It was formed at the site of a large tectonic depression of the earth's crust during the Alpine era of mountain building at the junction of the Baltic crystalline shield with the sedimentary strata of the Russian Platform. After the melting of the ice sheet, there was a vast expanse of water connecting the North Sea with the White Sea. This process began 18-20 thousand years ago. 13 thousand years ago the glacier finally left the territory of Lithuania. When the ice melted, water filled the depressions in the Baltic Sea - this is how the cold glacial Baltic Lake was formed, which at different periods connected with the Atlantic Ocean. This lake existed 13-10 thousand years ago.

Somewhat later, the glacier left the Central Swedish Lowland. The resulting channel connected the lake with the Atlantic Ocean. With the new arrival of the glacier, the level of the glacial lake began to rise, and with its departure it dropped by 40 - 50 m. Large areas of land opened up. This is how the Yoldian Sea was formed, which received its name from the abundance of mollusks that lived in it (from the Latin Yoldia arctica). The compensatory uplift of the continental plate, which occurred in the southern part of the Baltic Sea basin, deprived the Yoldian Sea of ​​its connection with the Atlantic Ocean. The rivers sharply reduced the salinity of this water basin and raised its level. This is how Ancylus Lake was formed 9 thousand years ago (the name comes from the name of the mollusks Ancylus fluviatilis). Its deposits were preserved at a depth of 16-18 m. At this stage of the formation of the Baltic Sea, the climate was warm and dry.

7.5 thousand years ago, the salty waters of the Atlantic Ocean broke into Lake Ancylus, and the Littorina Sea was formed (the name comes from the name of the mollusks Littorina littoraea). 4 thousand years ago, the Baltic Sea gradually acquired its modern appearance: its salinity decreased, and modern animals and plants began to predominate.

Salinity
The Baltic Sea is the largest sea in the world with the lowest salt content. Its waters are a mixture of salt water from the ocean and fresh water coming from numerous rivers. The degree of sea salinity in different places has different indicators, which is due to the weak vertical movement of water layers. If in the southwestern part of the sea it is 8%, in the western part 11%, then in the central water area it is 6%, and in the Gulf of Finland, Riga and Bothnia it barely exceeds 2-3% (cf. the average salinity of the World Ocean - 35%o).

The presence of certain types of fish in a particular area is also associated with varying degrees of water salinity. The flora and fauna of the Baltic Sea have a transitional character from the sea to a freshwater lake. So, often sea shellfish, like oysters, Mua
trunata, Littorina littoralis, etc. are only in the west. parts of the sea where the water is saltier. Along with marine fish, this sea is also home to freshwater fish - perch, bream, grayling, whitefish and others. In areas of high salinity and great depth, cod predominate, different kinds herring, herring, flounder, turbot, goby, eelpout, sprat. Less common, but still found, are salmon - sea trout (trout), whitefish and Baltic salmon (a type of salmon). There are a lot of three-spined sticklebacks and small fish. There are seals near the Åland Islands.

Tidal fluctuations in the Baltic are only a few centimeters. This is explained by the fact that the ocean tidal wave, reaching the coast of Denmark, loses its strength by almost 90% or subsides completely. However, the water level in the Baltic Sea changes frequently and sharply, due to the western and northwestern winds, which drive water into the Kaliningrad and Curonian Lagoons, as if locking weak river currents in their channels, not allowing them to reach the sea. If the winds blow from the south and east, the opposite phenomenon occurs, and in some places the sea moves away from the coast, forming islands of land interspersed with areas of sandbanks. Fluctuations in water temperatures are also associated with this. In summer, the water temperature ranges from 14° to 20° (sometimes higher, but the average level is 18-19°). The heated warm water is driven away from the shore by the frequent winds in these places, and bottom, deep currents bring colder layers of water. So in a short time the water temperature can drop to 8-9°. Summer in the Baltic It is never hot, but winter, in turn, is never cold. In winter, the Baltic Sea freezes, but this happens mainly along the coast, where solid ice forms a small strip or fills the bays, and the Curonian Lagoon freezes earlier than the Kaliningrad Lagoon. It should be noted that the reliability of the ice cover of bays is not the same everywhere, so fishing from such ice is always associated with a known risk to life. In addition, in some places the ice has large irregularities and has a significant drift speed. You can often see cracks and breaks along the coast, especially if the weather is windy. The accumulation of ice sometimes takes on bizarre shapes, especially if blocks of ice collide with rocks or sandbanks. Autumn and winter the role of winds increases. South-westerly Atlantic winds bring warmth, and long thaws occur, accompanied by sleet and rain.
The most dangerous time for fishing is when accompanied by strong winds. In a word, the wind is the decisive factor that “makes the weather” throughout the Baltic Sea. Winds in Palanga (Lithuania) have interesting names: seawater(western), predominant in this part of the coast; terrestrial- east wind blowing towards the sea; goat- southeast; Finnish- northwestern. And there is more amber wind(Bernsteinwind - German Bernsteinwind) a weakening north-west wind from the sea on the Baltic coast, which, during the sea swell, helps wash out the so-called amber grass from the exposed amber layers and drives algae with amber to the shore. They flow into the Baltic Sea rivers: Neva, Narva, Western Dvina (Daugava), Venta, Neman, Vistula, Oder. Large islands: Bornholm (Denmark), Gotland, Öland (Sweden), Saaremaa, Hiiumaa (Estonia), Rügen, Usedom (Germany), Aland. Large bays: Bothnian, Finnish, Riga, Curonian.

Gulf of Riga- a bay in the east of the Baltic Sea between Latvia and Estonia. Partially separated from the rest of the sea by the Estonian island of Ezel (Saaremaa). The most important cities along the coast of the Gulf of Riga are Riga and Pärnu. The Estonian island of Ruhnu is located in the Gulf of Riga. Total area: 16300 km², max. length: 174 km, max. width: 137 km, max. depth: 67 m, inflowing rivers : Zap. Dvina (Daugava), Courland Aa (Lielupe), Livlyandskaya Aa (Gauja), Salis (Salaca).Main ports: St. Petersburg, Kaliningrad (Russia), Tallinn (Estonia), Riga, Ventspils, Liepaja (Latvia), Klaipeda (Lithuania), Gdansk-Gdynia, Szczecin (Poland), Rostock, Kiel, Lubeck (Germany), Copenhagen, Malmo , Stockholm, Luleå, Umeå, Gävle, Sundsvall, Hudikval (Sweden), Turku, Helsinki, Rauma, Pori, Vaasa, Kokkola (Finland).

Resorts: Pärnu (Estonia), Jurmala, Liepaja, Pavilosta (Latvia), Palanga, Sventoji, Neringa (Lithuania), Kolobrzeg, Ustka (Poland), Heringsdorf, Warnemünde, Binz (Germany), etc.