What does the Baltic Sea look like? Svetlovodsk and Zelenogradsk are the best Russian resorts. Formation of the Baltic Sea

BALTIC SEA (Late Latin - Mare Balticum, among the ancient Slavs - the Varangian Sea or the Svean Sea), the inland sea of ​​the Atlantic Ocean, between the Scandinavian Peninsula and the mainland shores Northwestern Europe. Washes the shores of Sweden, Finland, Russia, Estonia, Latvia, Lithuania, Poland, Germany, Denmark. In the southwest it is connected to the North Sea by the Danish Straits. maritime border Baltic Sea passes through the southern entrances of the Øresund, Great Belt and Small Belt straits. The area is 419 thousand km 2, the volume is 21.5 thousand km 3. Greatest depth 470 m. Depths above the thresholds of the Danish Straits: Darser - 18 m, Drogden - 7 m. The cross section above the thresholds 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 coves. The largest bays: 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, mostly of skerry and fjord types, in the south and southeast - for the most part low-lying, lagoon type, with sandy and pebble beaches. Most major islands: Gotland, Bornholm, Saaremaa, Muhu, Hiiumaa, Öland, Rügen. There are many small rocky islets - skerries, located along the northern shores (there are over 6 thousand in the Aland Islands group).

relief and geological structure bottom. The Baltic Sea is shallow, lies completely within the shelf, depths up to 200 m occupy 99.8% of its area. The most shallow are the Gulfs of Finland, Bothnia and Riga. These areas of the bottom have a leveled accumulative relief and a well-developed cover of loose sediments. Most of the bottom of the Baltic Sea is characterized by a strongly dissected relief. The bottom of its basin has depressions delimited by elevations and the bases of the islands: in the west - Bornholmskaya (105 m) and Arkonskaya (53 m), in the center - Gotlandskaya (249 m) and Gdanskaya (116 m); to the north of the island of Gotland, the deepest depression - Landsortskaya (up to 470 m) stretches from the northeast to the southwest. Numerous stone ridges, ledges are traced in the central part of the sea - continuations of glints 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. extreme southwestern part sea ​​enters the limits of the young Western European platform. The bottom in the north of the Baltic Sea is composed mainly of Precambrian age complexes overlain by a discontinuous cover of glacial and modern marine deposits. Silurian and Devonian sediments take part in the bottom structure in the central part of the sea. The ledges traced here are formed by the Cambrian-Ordovician and Silurian rocks. The Paleozoic complexes in the south are overlain by a thick layer of glacial and marine sediments.

During the last ice age (late Pleistocene), the Baltic Sea depression was completely covered by an ice sheet, after which the Baltic Glacial Lake was formed. At the end of the late Pleistocene, about 13 thousand years ago, the lake joined the ocean, and the depression was filled with sea water. Communication with the ocean was interrupted in the interval of 9-7.5 thousand years ago, followed by a marine transgression, the deposits of which are known on the modern coast of the Baltic Sea. Uplift continues in the northern part of the Baltic Sea, at a rate of up to 1 cm per year.

Bottom sediments at depths of more than 80 m are represented by clayey silts, under which banded clay occurs on glacial deposits; at shallower depths, the silt is mixed with sand, in coastal areas sands are common. 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 baric centers: the Icelandic Low and the Azores High in the west and the Siberian High in the east. Cyclonic activity reaches its greatest intensity in the autumn-winter months, when cyclones bring cloudy, rainy weather with strong western and southwestern winds. average temperature air in February from -1.1°С in the south, -3°С in the central part of the sea, to -8°С in the north and east, in the northern part of the Gulf of Bothnia to -10°С. Rarely and for a short time, the cold arctic air penetrating the Baltic Sea lowers the temperature to -35°C. In summer, westerly winds also blow, but of low 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 the rest of the sea. Rare inflows of warm Mediterranean air cause short-term temperature rises up to 22-24°C. Annual precipitation varies from 400 mm in the north to 800 mm in the south. The greatest number of days with fogs (up to 59 days a year) is observed in the south and in the central part of the Baltic Sea, the smallest (22 days a year) - in the north of the Gulf of Bothnia.

Hydrological regime. The hydrological conditions of the Baltic Sea are determined by its climate, significant inflow of fresh water and limited water exchange with the North Sea. About 250 rivers flow into the Baltic Sea. River flow averages 472 km 3 per year. The largest rivers: Neva - 83.5 km 3, Vistula - 30, Neman - 21, Western Dvina - 20 km 3 per year. Freshwater runoff is unevenly distributed throughout the territory. The Gulf of Bothnia receives 181, the Gulf of Finland - 110, the Gulf of Riga - 37, central part Baltic Sea - 112 km 3 per year. Quantity fresh water, coming with precipitation (172 km 3 per year), is equal to evaporation. Water exchange with the North Sea averages 1660 km 3 per year. Fresher waters with a surface runoff flow from the Baltic Sea to the North Sea, salty North Sea water with a near-bottom current flows through the straits from the North Sea. Strong westerly winds usually increase the inflow, east winds - 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 during the year varies from 0 to 20 ° C, salinity is usually in the range of 7-8‰. This water mass is formed in the sea itself as a result of the interaction of sea water with fresh water, precipitation and river runoff. It has winter and summer modifications, which differ 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. The renewal and ventilation of bottom waters are highly dependent on the inflow of North Sea water, which is subject to interannual variability. With a reduction in the inflow of salt water into the Baltic Sea by great depths and in the depressions of the bottom relief, conditions are created for the appearance of dead events. seasonal changes water temperatures capture the layer from the surface to 50-60 m and usually do not penetrate deeper.

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

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

The tides in the Baltic Sea are weakly expressed due to a slight connection with the ocean, the height is 0.1-0.2 m. The surge fluctuations in the level reach significant values ​​(at the tops of the bays up to 2 m). The combined action of the 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 the Gulf of Finland. Seiche waves with surge western winds sometimes cause a rise in the level at the top of the Gulf of Finland up 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 water temperature on the surface 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 southern regions reaches 20°C. In February, in the open part of the sea, the water temperature on the surface is 1-3°C, in bays and bays below 0°C. The salinity of water on the surface is 11‰ at the outlet of 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 an intensification of the process of sea ice formation. Ice formation begins in November in the bays and along the coast, later - in the open sea. IN harsh winters ice cover covers the entire northern part seas and coastal waters of its central and southern parts. The thickness of landfast (fixed) ice reaches 1 m, drifting - from 0.4 to 0.6 m. Ice melting begins at the end of March, spreads from southwest to northeast and ends in June.

Research history. 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 Aland Islands, in the 2nd half of the 7th-8th centuries they reached west coast The Baltics discovered the Moonsund archipelago, for the first time penetrated the Gulf of Riga, in the 9th-10th centuries they used the coast from the mouth of the Neva to the Gdansk Bay for trade and piracy. Russian hydrographic and cartographic work began in the Gulf of Finland in the early 18th century. In 1738, F. I. Soymonov published an atlas of the Baltic Sea, compiled from Russian and foreign sources. In the middle of the 18th century, A. I. Nagaev conducted many years of research, who compiled a detailed sailing chart of 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 Department 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 guidance 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 fresh waters of the bays (crucian carp, bream, pike, pike perch, chub), the Baltic salmon herd and purely marine species distributed mainly in the central part of the sea (cod, herring, smelt, vendace, sprat). Baltic herring, sprat, herring, smelt, river flounder, cod, perch and others are fished. Unique object fishing - eel. Placers of amber are common on the coast of the Baltic Sea, mining is carried out near Kaliningrad (Russia). Oil reserves have been discovered at the bottom of the sea, and industrial development has begun. Iron ore is mined off the coast of Finland. The significance of the Baltic Sea as a transport artery is great. 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, Sweden is carried out through the Baltic Sea.

The cargo turnover is dominated by oil products (from the ports of Russia 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); An important role is also played by machinery and equipment, the major producers and consumers of which are the countries located on the shores and in the basin of the Baltic Sea. The largest ports of the Baltic Sea: St. Petersburg, Kaliningrad (Russia), Tallinn (Estonia), Riga (Latvia), Gdansk, Gdynia, Szczecin (Poland), Rostock - Warnemünde, Luebeck, Kiel (Germany), Copenhagen (Denmark), Malmö , Stockholm, Luleå (Sweden), Turku, Helsinki, Kotka (Finland). In the Baltic Sea, maritime passenger and ferry service: Copenhagen - Malmö, Trelleborg - Sassnitz (rail ferries), Nortelje - Turku (car ferry), etc. On the southern and southeast coasts many resorts.

Ecological state. The Baltic Sea, which has a difficult water exchange with the World Ocean (water renewal lasts about 30 years), is surrounded by industrial developed countries and is experiencing an extremely intense anthropogenic load. The main environmental problems are related to the burial of chemical weapons at the bottom of the sea, the discharge of sewage into the sea major cities, washing off chemical fertilizers used in agriculture, and especially with shipping - one of the most intensive in the world (mainly oil tankers). After the entry into force in 1980 of the Convention for the Protection of the Marine Environment of the Baltic Sea ecological situation improved due to the introduction of a large number of wastewater treatment plants, a reduction in the use of chemical fertilizers, control of technical condition courts. The concentration of toxic substances such as DDT and polychlorinated biphenyls, petroleum hydrocarbons has decreased. The content of dioxins in the Baltic herring is 3 times lower than the MPC, 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 seas of the USSR. 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. SPb., 1994. T. 3. Issue. 2; Zalogin B. S., Kosarev A. N. Morya. M., 1999.

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 the relief, temperature and features. coastline. The Baltic is of great historical and geopolitical importance for Russia.

Geographical position

The Baltic Sea on the map is located in northern Europe and belongs to the Atlantic basin. It is bounded by 54°46′ and 65°56′ North latitude and 9°57′ and 30°00′ East longitude. The extreme points that the Baltic Sea has on the map: near the Arctic Circle in the north, near Wismar in the south, the eastern one is near St. Petersburg and the western extreme point located in the Flensburg area.

Relief and depths

The bottom relief has slight differences from the outlines of the shores that limit 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 gently sloping, flat, with sandy beaches. The rocky shore and uneven rocky bottom are located in the northern part. The depth and relief of the Baltic Sea are different in different areas. The bottom has a very complex dissected surface. There are depressions that delimit the uplands and bases of the islands that the Baltic Sea includes.

Depths elsewhere are shallow. For example, there are areas of pronounced accumulative relief - these are the shallow Gulfs of Finland, Riga and Bothnia.

Thus, the depth of the Baltic Sea is less than 200 meters. The Landsortskaya depression is different. The maximum depth of the Baltic Sea is located in this area and is about 470 meters. The Landsort Basin extends in a southwestern direction. The rest are of lesser depth: Gotlandskaya - 249 m and Gdanskaya - 116 m in the central part of the sea, Arkonskaya - 53 m and Bornholmskaya - 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 (Small 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

The Neva Bay is the eastern section of the Gulf of Finland. At a distance of about 50 km from St. Petersburg is located on which the city of Kronstadt was built. The dam connects the island city and St. Petersburg, the highway is laid along the dam, so that 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. It starts there Saimaa Canal leased by Finland. It performs the function transport route, and is also popular with tourists in warm weather. Guests come here for the beauty of landscapes, and for duty-free shopping.

Coast

The coast of the Baltic Sea is diverse. Latvia has an accumulation-type coast 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. Leveled shores border most of the sea, in particular, belong to Poland. And they are formed under the influence of prevailing winds and coastal currents. Fjords are narrow and deep sea bays with towering steep and rocky shores that surround the sea from the north. They were formed by flooding of tectonic faults and river valleys. The skerry shore appeared as a result of flooding of territories with smoothed glaciers composed of crystalline rocks. These hills protrude above the sea surface in the form of many 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 segment of the coast, only 7%, instead of the former 25%, which brings annual losses to the state. Therefore, one port was laid in Primorsk near Vyborg, which will specialize in coal and dry cargo. And the second port is located in the Luga Bay, it will be oil loading.

Tectonic processes

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

Currently, the next stage of separating the sea from the ocean and turning it into fresh lake. It is characterized by the rise of the bottom of the Gulf of Bothnia during the year by several centimeters and flooding. southern coasts. Such processes create a need for northern ports to lengthen their piers. To save the low parts of the coast, embankments are being 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 is from 0 to 20 meters, in some places - from 0 to 90 meters with a temperature of 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 with the seasons. In summer, cold intermediate water masses are more pronounced, formed in connection with a significant warming of the sea surface.

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 straits of the Small and Great Belt and their mixing.

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

Features of water temperature in the Baltic Sea

Separate areas of the sea are distinguished by the peculiarities of the structure of the waters. So, Bornholmsky district has a warm layer (7-11 degrees) both in summer and in winter. It is formed warm waters coming here from the more heated Arkon basin. In it, due to the shallow depth of the sea and the movement of waters in the horizontal plane, there is no cold intermediate layer in summer.

Seasonal change in temperature

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

In summer, surface waters in different parts of the sea also differ in temperature. The 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, as well as near the western coasts, the temperature drops. In addition, a cold current from the Gulf of Bothnia flows south along the coast of Sweden.

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

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

The Baltic Sea is the northern marginal body of water in Eurasia. It cuts deep into the land, and due to this it belongs to the water flows of the internal type. The sea fills the waters of the Atlantic. It is located in Northern Europe. The Baltic countries have access to the Baltic Sea. And also such states as: Denmark, Sweden, Finland, Germany, Russia and Poland. The stream connects with the ocean through the system and the North Sea.

The area of ​​the reservoir is about 415 thousand square km. The volume of the water mirror is more than 20 thousand cubic meters. km. The deepest gutter is 470 meters.

Hydrology

The Baltic Sea, whose salinity greatly affects the flora and fauna, is filled with a huge amount of fresh water. Precipitation is their constant source. Salt streams penetrate into the reservoir due to bays and tributaries. The tides have insignificant levels and, as a rule, their magnitude is not more than 20 cm.

Constantly located within a radius of one mark. Air masses can exert a strong influence on it. Near the coast, the water level can rise up to 50 cm, in narrower places - up to 2 meters.

There are practically no storms on the water stream. Like other seas washing Russia, the Baltic reservoir is calm, and rarely when its waves are able to reach a height of 4 meters. Most of all it storms in autumn, in November. Maximum fluctuations - 7-8 points. In winter, they practically stop, this is facilitated by ice.
The constant flow of the Baltic Sea is small. Within 10-15 cm/s. The maximum current increases during storms up to 100-150 cm/s.
The tides of the Baltic Sea are almost imperceptible. This is facilitated by the isolation of the water flow to a greater extent. Their level varies within 20 meters. The maximum increase in water level is in August and September.

A significant part of the coast is covered with ice from October to April. South part and the center of the sea, but glaciers can drift along them during the thawing period (June-August).

The Baltic Sea is rich in natural resources. Oil reserves are hidden here, new deposits are being developed. Large deposits of amber have also recently been found. The Nord Stream gas route runs along the bottom of the sea.

And the Baltic Sea is rich in fish and seafood. IN last years the ecology of the stream has deteriorated significantly. The waters are clogged with toxins coming from large rivers. The presence of dumps of chemical weapons is also recorded.

Due to the shallow depth of the sea, shipping is not very developed here. Only light craft are able to cross the watercourse without problems. Most major ports Baltic Sea: Vyborg, Kaliningrad, Gdansk, Copenhagen, Tallinn, St. Petersburg, Stockholm.

The waters of this reservoir are unsuitable for the development of resort tourism, but nevertheless there are sanatoriums and clinics on the coastal part. These are Russian resort cities Svetlogorsk, Zelenogorsk, Sestroretsk, Latvian Jurmala, Lithuanian Neringa, Polish Koszalin and Sopot, German Albek and Binz.

Brief description of water temperature and sea salinity

In the central part of the Baltic Sea, as a rule, the temperature rarely exceeds 15-18 ° C. At the bottom, it is about 4 degrees. The bay often has calm weather and +9..+12 o C.

The Baltic Sea, whose salinity decreases in the direction from west to east, at the beginning of the current has an official indicator of 20 ppm. At depth, this figure increases by 1.5 times.

Name

For the first time, the etymological name "Baltic" is found in a historical treatise of the 11th century. More early title seas - Varangian. It is it that is mentioned in the famous Tale of Bygone Years.

extreme points

Extreme points of the Baltic Sea:

• southern - Wismar (Germany), coordinates - 53° 45` N. sh.;
• north - Arctic Circle coordinates - 65° 40` s. sh.;
• eastern - St. Petersburg (Russia), coordinates - 30 ° 15` in. d.;
• western - Flensburg (Germany), coordinates - 9 ° 10` in. d.

Geographical characteristics: territory, tributaries and bays

The Baltic Sea (salinity and its characteristics are described below) is extended from the southwest to the northeast for 1360 km. The greatest width is located between the cities of Stockholm and St. Petersburg. It is 650 kilometers.

According to historical data, the Baltic Sea has existed for about 4 thousand years. In the same period of time, the Neva (74 km) begins its existence, which flows into this reservoir. In addition to it, more than 250 rivers merge with the stream. The largest of them are Vistula, Oder, Narva, Neman, Zapadnaya Dvina.

Some ports of the Baltic Sea lie on its major bays X. In the north is the Gulf of Bothnia, the largest and deepest. In the east - Riga, located between Estonia and Latvia, Finnish, washing the shores of Finland, Estonia, Russia, and Due to the fact that the latter is separated from the sea by a sandy spit, the water in the stream is almost fresh. This is a unique feature.

The average depth of the Baltic Sea is 50 meters, the bottom is completely within the mainland. This nuance makes it possible to attribute it to inland continental water bodies.

Islands

More than 200 islands of different sizes are located in the sea. They are located unevenly both near the coast and far from them. The largest islands in the Baltic are Zealand, Falster, Mön, Langeland, Lolland, Bornholm, Funen (belong to Denmark); Öland and Gotland (Swedish islands); Fehmarn and Rügen (refers to Germany); Hiiumaa, Saaremaa (Estonia).

Coastline

The Baltic Sea (the ocean strongly affects it with its waters) has a different coastline along the entire perimeter of the waters. In the northern part, the bottom is uneven, rocky, and the coast is indented with small bays, ledges and small islands. The southern part, on the contrary, has a flat bottom, and a low-lying coast, with a sandy beach, which in some areas is represented by small dunes. A frequent occurrence on the young coast - sandbars deep into the sea.
The sedimentary bottom is represented by green, black silt (of glacial origin) and sand, and the soil consists of stones and boulders.

Salinity and its regular changes

Due to the large amount of precipitation and the powerful water flow from the rivers, the Baltic Sea (the salinity of the reservoir is relatively low) is filled with an excess of fresh water. It is distributed unevenly. Where the Baltic reservoir enters deep into the shore, the water is practically fresh, and the North Sea influences its salinity. This position is not permanent. Storm winds contribute to the mixing of water.
Based on this, the salinity of the Baltic Sea is low. A decrease in its level is typical for the coastline, the most a large number of ppm - at the bottom.
In the territory where the watercourse meets the straits in the west, the salinity of the waters is up to 20 ‰ on the sea surface, at the bottom - 30 ‰. Off the coast of the Gulf of Bothnia and the Gulf of Finland, the lowest indicator. It does not exceed 3‰. The level from 6 to 8‰ is characteristic of the waters of the central part.

Seasonality also affects the distribution of salinity in the Baltic Sea. So, in the spring-summer season, it decreases by 0.5-0.2 ppm. This is due to the fact that melted rivers carry fresh water to the sea. And in autumn and winter, on the contrary, it increases due to the influx of cold northern masses.

The change in the salinity of the sea is one of the important reasons that regulate the biological, physical and chemical processes on the coast. Partly due to the freshness of the water, the coast has a loose structure.

extreme north point The Baltic Sea is located near the Arctic Circle (65 ° 40 "N), the extreme south is near the city of Wismar (53 ° 45" N).

extreme western point located in the Flensburg area (9 ° 10 "E), the extreme east - in the St. Petersburg region (30 ° 15" E)

The surface area of ​​the sea (without islands) is 415 thousand km². The volume of water is 21.5 thousand km³. Due to the huge flow of rivers, the water has low salinity and therefore the sea is brackish. It is the largest sea in the world with such a feature.

Geological history

The severity of the ice caused a significant deflection of the earth's crust, part of which was below sea level. With the end of the last ice age, these territories are freed from ice, and the depression formed by the trough of the crust is filled with water:

Physical-geographical sketch

The Baltic Sea goes deep into the land of Europe, washes the shores of Russia, Estonia, Latvia, Lithuania, Poland, Germany, Denmark, Sweden and Finland.

Large bays of the Baltic Sea: Finnish, Bothnian, Riga, Curonian (freshwater bay, separated from the sea by the sandy Curonian Spit).

Major rivers emptying into the Baltic Sea are the Neva, Narva, Zapadnaya Dvina (Daugava), Neman, Pregolya, Vistula, Oder and Venta.

Bottom relief

The Baltic Sea lies within the continental shelf. The average depth of the sea is 51 meters. Small depths (up to 12 meters) are observed in the areas of shoals, banks, near the islands. There are several basins in which depths reach 200 meters. The deepest basin is Landsortskaya ( 58°38′ N. sh. 18°04′ in. d. HGIOL) with a maximum sea depth of 470 meters. In the Gulf of Bothnia, the maximum depth is 293 meters, in the Gotland Basin - 249 meters.

The bottom in the southern part of the sea is flat, in the north - uneven, rocky. In coastal areas, sands are common among the bottom sediments, but most of the seabed is covered with deposits of green, black or brown clayey silt of glacial origin.

Hydrological regime

A feature of the hydrological regime of the Baltic Sea is a large excess of fresh water, formed due to precipitation and river runoff. The brackish surface waters of the Baltic Sea through the Danish Straits go to the North Sea, and the salty waters of the North Sea enter the Baltic Sea with a deep current. 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 go both to the North and to the Baltic Sea.

In 2003, there were 21 reported cases of chemical weapons being caught in fishing nets in the Baltic Sea, all consisting of clots of mustard gas weighing approximately 1,005 kg.

In 2011, paraffin was released into the sea, which spread throughout the sea. Tourists found large pieces of paraffin on the beach. [ ]

Natural resources

The development of deposits may be hindered by stringent environmental requirements associated with an insignificant water exchange between the sea and the ocean, anthropogenic pollution of water with runoff from the territory of coastal states, contributing to enhanced eutrophication.

The Nord Stream gas pipeline is laid along the bottom of the Baltic Sea.

Sea transport

Recreational resources

Titles

First time title Baltic Sea(lat. mare balticum) is found in Adam of Bremen in his treatise Acts of the Archbishops of the Hamburg Church" (lat. Gesta Hammaburgensis Ecclesiae Pontificum) .

In the Tale of Bygone Years, the Baltic Sea is named Varangian by sea. Historically, in Russian the sea was called Varangian, and then Sveisky(Swedish). Under Peter I, it was strengthened German title - Ostsee sea. Since 1884, the modern name has been used.

see also

Notes

1. // Military encyclopedia: [in 18 volumes] / ed. V. F. Novitsky [i dr.]. - St. Petersburg. ; [ M. ] : Type. t-va I. D. Sytin, 1911-1915.

The Baltic Sea (from antiquity until the 18th century in Russia it was known as the "Varangian Sea") is an inland marginal sea, deeply protruding into the mainland. The Baltic Sea is located in northern Europe belongs to the Atlantic Ocean basin.

The northernmost point of the Baltic Sea is located near the Arctic Circle, the southernmost point is near the city of Wismar (Germany). The extreme western point is located near the city of Flensburg (Germany), the extreme eastern one is in the region of St. Petersburg. Due to the large elongation along the meridian and the parallel, certain areas of the Baltic Sea are located in different physiographic and climatic zones. This, in turn, affects the oceanological processes occurring in the sea and its individual regions.
Sea area: 415 thousand kilometers. Depth: average - 52 meters, maximum - 459 meters.

The Baltic Sea has three large bays: Bothnian, Finnish, Riga. About 250 rivers flow into it, including the Neva, Vistula, Neman, Daugava, Oder.

Connection of the Baltic Sea with Atlantic Ocean carried out through the North Sea, the Skagerrak, Kattegat and Danish Straits (Great and Small Belt, Øresund (Sund) and Fehmarn Belt), however, this connection is difficult due to the shallowness of the straits (depth at the rapids 7-18 meters). Therefore, the waters of the Baltic are very slowly renewed due to the cleaner Atlantic waters. The period of complete water renewal in the Baltic Sea is about 30-50 years.

The Baltic Sea has a low salt content. Its waters are a mixture of salt water from the ocean and fresh water coming from numerous rivers. The degree of salinity of the sea in different places has indicators that differ from each other, which is due to the weak vertical movement of water layers. If in the southwestern part of the sea it is 8 ppm (i.e., each kilogram of water contains 8 g of salt), in the western part it is 11 ppm, then in the central water area it is 6 ppm, and in the Gulf of Finland, Riga and Bothnia it barely exceeds a mark of 2-3 ppm (the average salinity of the oceans is 35 ppm).

The length of the Baltic coastline is 7 thousand kilometers. The coast is distributed among the countries as follows: Sweden owns 35% of the coast, Finland - 17%, Russia - about 7% (about 500 kilometers). The rest of the coast is divided among themselves by Lithuania, Latvia, Estonia, Poland, Germany, Denmark. The coast of the sea and adjacent land areas are heavily populated and intensively used by humans. Transport complexes and large industrial enterprises are located on the coast. The Baltic basin accounts for one tenth of the world's maritime traffic.

The Baltic Sea is heavily polluted as a result of the active activities of the people living on its shores. The environmental problems of the Baltic Sea are related to many aspects of society, such as energy production and consumption, industry, forestry, agriculture, fisheries, tourism, transport, wastewater treatment.

The main environmental problems of the Baltic

Firstly, the excess supply of nitrogen and phosphorus to the water area as a result of flushing from fertilized fields, municipal wastewater from cities and waste from some enterprises. Since the water exchange of the Baltic is not very active, the concentration of nitrogen, phosphorus and other wastes in the water becomes very strong. Due to nutrients in the sea, organic matter is not completely recycled, and due to a lack of oxygen, they begin to decompose, releasing harmful to marine life hydrogen sulfide. Dead hydrogen sulfide zones already exist at the bottom of the Gotland, Gdansk, and Bornholm depressions.

The second significant problem in the Baltic is water pollution by oil. Thousands of tons of oil annually enter the water area with various effluents. The film of oil that covers the surface of the water mirror does not allow oxygen to pass into the depths. Also, toxic substances harmful to living organisms accumulate on the surface of the water. Oil spills in most cases occur in coastal and shelf zones, the most productive and at the same time vulnerable areas of the sea.

The third problem in the Baltic Sea is the accumulation of heavy metals. Mercury, lead, copper, zinc, cobalt, nickel mainly enter the Baltic waters with atmospheric precipitation, the rest gets through direct discharge into the water area or with river runoff of household and industrial waste. The amount of copper entering the water area is annually about 4 thousand tons, lead - 3 thousand tons, cadmium - about 50 tons, and mercury - 33 tons, per 21 thousand cubic kilometers of the water volume of the water area.

Baltic Sea thanks to geographic location has always been at the crossroads historical events. There is more than one ship graveyard at the bottom of the Baltic. Many wrecks carry dangerous goods. The containers in which the goods are located are destroyed over time.

For decades, the Baltic practiced the flooding and disposal of obsolete bombs, shells, chemical munitions. After the end of World War II, by a joint decision of the countries of the anti-Hitler coalition (USSR, Great Britain and the USA) and in accordance with the decision of the Potsdam Conference in 1951, in various parts of the Baltic, as well as in the straits connecting the Baltic Sea with the North Sea, more than 300 thousand tons were flooded German chemical weapons and ammunition.

For more than half a century, ammunition has been lying on the bottom of the Baltic, creating a potential mortal threat. Metal in sea ​​water rust corrodes, and toxic substances can enter the water at any time.

The material was prepared on the basis of information from open sources