Everything about the baltic sea. Baltic Sea: recreation

15.11.2019

The Baltic Sea is a sea located in Northern Europe, inland and belongs to the basin of a huge Atlantic Ocean.

Origin

The Baltic Sea lies on the stable Russian tectonic plate, the formation of which ended approximately 1.8-2 billion years ago.

30 million years ago, the plate took the position on which it is held now. During the long ice age, which began about 700 million years ago, the entire territory of Northern Europe was covered with a thick layer of ice and snow.

Huge ice masses caved in the continental rock - thus creating a "hollow" for the future sea. And when the last ice age came to its end - two tens of millennia BC, all the ice melted and the Baltic Sea formed in their place.

Formation of modern Baltic Sea happened in several stages, which should be discussed in more detail. First, the so-called Baltic glacial lake was formed, which happened fourteen thousand years BC. And ten thousand years BC, through the strait in Sweden, the territory of the modern sea was filled with sea water - this is how the Yoldievsky was formed.

Baltic Sea. storm photo

The Ancyl Sea dates back to 9-7, 5 millennia - when access to the world's oceans was closed. Around the middle of the eighth millennium, the sea merged with the ocean due to the rise in ocean levels, which formed the Lothyron Sea. And the modern Baltic Sea appears around the fourth millennium BC.

Characteristic

The area of the Baltic Sea, excluding the islands, reaches 415 thousand square kilometers. But the volume of water for a rather large sea reaches only 21, 5 thousand cubic kilometers. Consequently, the depth of the Baltic Sea is shallow. The average depth revolves around 50 meters, and the greatest depth is only half a kilometer. The coastline is approximately eight thousand kilometers long.

The climate of the sea is temperate maritime, influenced by the Atlantic Ocean, from where cyclones with westerly winds come. Precipitation often falls, fog appears, especially in winter and spring. Storms are rare, and the wave height is not higher than 4 meters. The tides are almost invisible, usually no more than 20 centimeters.

Baltic Sea Kaliningrad Region photo

In summer, the water temperature reaches an average of about eighteen degrees Celsius. In winter, and especially in February, it can reach zero levels. Coastal waters are frozen in the east and north, the southern and central parts of the sea are open. Only if the winter is very cold, then the entire Baltic Sea is covered with ice, but this rarely happens.

For the most part, the salinity of water in the sea is extremely low (7 - 20 ppm), since many freshwater rivers flow into the sea. In turn, this has served the modest species diversity of the local flora and fauna. However, low salinity plays an important role for humans. At critical moments, water can be directly from the sea - but not for too long.

Unlike other seas, the Baltic can give you a source of water for a short time, which can even save your life. But the constant and long-term drinking of such water can be harmful to your health.

What rivers flow into the Baltic Sea

The following flows into the Baltic Sea big rivers which are also of great importance for industry and infrastructure:

Western Dvina,
Neva,
Venta,
Pregolya, Narva,
Oder
Vistula.

The relief of the Baltic Sea

As already mentioned, the average depth of the seabed reaches fifty meters, since the sea is part of the continental shelf itself. At the bottom of the sea there are several hollows and the depth of most of them hardly reaches two hundred meters, but the deepest of them goes down to 470 meters.

Baltic sea in winter photo

In the southern part of the sea, the bottom is flat, while in the north it is predominantly rocky.

Cities

Among the big cities on the Baltic Sea are St. Petersburg, Klaipeda, Svetlogorsk and Zelenogradsk, Jurmala, Parnu and Narva, Albek, Bints and many others. All of them have become either favorite places for tourists or just resort towns where hundreds of thousands of people come to rest every year.

Animal world

The Baltic Sea is a very important industrial base as it is the source of a huge amount of industrially important fish species. The very species diversity in the world of fish is small, but the number of representatives of each species is impressive. The small variety of fish is due to the fact that the water in the sea is mostly fresh, and there are not so many freshwater fish.

Svetlogorsk Kaliningrad region Photo

In areas where there is more salt water, the species diversity is somewhat greater, but still remains rather poor. At the very bottom of the sea, flounders and gobies live, as well as several species of molluscs and small crustaceans. In addition to them, worms also live on the seabed. There are several types of jellyfish in the Baltic Sea, among which there are quite huge ones.

Of the small fish, schooling Baltic sprats and three-spined sticklebacks can be noted. In areas with predominantly fresh water such river fish species as pike, perch, pike perch, roach, bream, burbot, whitefish, ide and some others, less common, live. Valuable industrial fish live in the Baltic Sea on a huge scale, and they include sprat, herring (makes up about half of the total catch in the Baltic Sea), flounder, salmon, cod and eel.

seal in the baltic sea photo

Seals in the Baltic Sea are represented by only three species, including the gray seal, the common seal pig or just the common seal. Sharks also live in the sea, although they are represented by only one species that does not pose a danger to humans - these are small katrans. In rare regions, it is very rare to find the more dangerous herring shark.

The northernmost point of the Baltic Sea is located as far as the North Pole;
The Slavs, in the days of Russia, called the sea Varangian, and all the inhabitants who sailed because of it - the Varangians;
The Nord Stream gas pipeline was laid between Germany and Russia, which is located at the very bottom of the Baltic Sea;
The Baltic Sea is also a huge base for oil production, which is now being carried out by the government of the Russian Federation;
The Baltic Sea is very heavily polluted with chemical waste, which is why the fish population is declining.

BALTIC SEA(Late Latin Mare Balticum, among the ancient Slavs - the Varangian Sea or Sveiskoye), the inland sea of the Atlantic Ocean, between the Scandinavian Peninsula and the continental shores of North-Western Europe. Washes the shores of Sweden, Finland, Russia, Estonia, Latvia, Lithuania, Poland, Germany, Denmark. In the southwest, it connects to the North Sea Danish straits . Sea border The B. m. Passes through the southern entrances of the Oresund, Great Belt and Little Belt straits. The area is 419 thousand km 2, the volume is 21.5 thousand km 3. The deepest 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 B. m. Juts deep into the continent of Eurasia. The highly indented coastline forms numerous bays and coves. The largest bays: Gulf of bothnia, Gulf of Finland, Gulf of Riga, Curonian Lagoon, Szczecin Gulf, Gdansk Bay. The shores of B. m. In the north are high, rocky, mainly of skerry and fjord types, in the south and southeast - for the most part low-lying, lagoon type, with sandy and pebble beaches. Most large islands: Gotland, Bornholm, Saaremaa, Muhu, Hiiumaa, Oland and Rügen. There are many small rocky islets - skerries located along the northern shores (there are over 6 thousand in the Aland Islands group).

Topography and geological structure of the bottom

The Baltic Sea is shallow, lies entirely within the shelf; depths of up to 200 m occupy 99.8% of its area. The Finnish, Bothnian and Riga bays are shallowest. Their bottom areas 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 highly dissected relief. The bottom of its basin has depressions, delimited by the heights and bases of the islands: in the west - Bornholm (105 m) and Arkonskaya (53 m), in the center - Gotland (249 m) and Gdansk (116 m); north of the island of Gotland from northeast to southwest stretches the most deep depression- Landsort (up to 470 m). Numerous stone ridges, in the central part of the sea, there are ledges - continuation of cliffs stretching from the northern coast of Estonia to the northern tip of the island of Öland, underwater valleys, glacial-accumulative relief forms flooded by the sea.

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

In the last glacial epoch (in the late Pleistocene) the basin of the B. m. Was completely covered by an ice sheet, after the melting of which the Baltic glacial lake was formed. At the end of the late Pleistocene, approx. 13 thousand years ago, there was a connection of the lake with the ocean and the cavity was filled with sea waters. Communication with the ocean was interrupted in the interval 9–7.5 thousand years ago, after which a marine transgression followed, deposits of which are known on the present-day coast of the Baltic Sea. In the northern part of the Baltic Sea, uplift continues, the rate of which reaches 1 cm per year.

Bottom sediments at depths of more than 80 m, they are represented by clayey silts, under which a strip clay lies on glacial deposits, at shallower depths silt is mixed with sand, and sands are widespread in coastal areas. There are boulders of glacial origin.

Climate

A temperate maritime climate with features of continentality is characteristic of B. m. Its seasonal features are determined by the interaction of baric centers: the Icelandic minimum and the Azores maximum in the west and the Siberian maximum in the east. Cyclonic activity reaches its highest intensity in the autumn-winter months, when cyclones bring cloudy, rainy weather with strong westerly and southwesterly winds. average temperature air in February from –1.1 ° C in the south, –3 ° C in the central part of the sea to –8 ° C in the north and east and to –10 ° C in the northern part of the Gulf of Bothnia. Rarely and for a short time, the cold Arctic air penetrating into the Baltic region lowers the temperature to -35 ° C. In summer, westerly winds also blow, but of little force, bringing cool, wet 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 ranges from 400 mm in the north to 800 mm in the south. The greatest number of days with fog (up to 59 days a year) is observed in the south and in the central part of Byelorussia, the smallest (22 days a year) - in the north of the Gulf of Bothnia.

Hydrological regime

The hydrological conditions of B. m. Are determined by its climate, significant influx of fresh water, and limited water exchange with the North Sea. Approx. Flows into B. m. 250 rivers. River flow averages 472 km 3 per year. Most large rivers: Neva - 83.5 km 3, Vistula - 30, Neman - 21, Western Dvina - 20 km 3 per year. Fresh runoff is distributed unevenly throughout the territory. The Gulf of Bothnia receives 181, the Finnish - 110, the Riga - 37, central part B. m. - 112 km 3 per year. Quantity fresh water atmospheric 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 current leave the Baltic Sea for the North Sea; salty North Sea water with a bottom current enters through the straits from the North Sea. Strong westerly winds usually intensify the inflow, and easterly - the flow of water from the B. m. Through the Danish straits.

The hydrological structure of B. m. In most regions 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 interaction sea waters with fresh waters of 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. The renewal and ventilation of bottom waters is highly dependent on the North Sea water supply, which is subject to interannual variability. With a reduction in the inflow of salt water into B. m., great depths and in the depressions of the bottom relief, conditions are created for the appearance of freezing phenomena. Seasonal changes in water temperature cover the layer from the surface up 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 with a height of 5–6 m and a length of 50–70 m are observed. The highest waves are observed in November. In winter, sea ice prevents the development of excitement.

In the B. m. Cyclonic (counterclockwise) circulation of waters, complicated by eddy formations of various scales, is observed everywhere. Constant current velocities are usually approx. 3-4 cm / s, but in some areas it sometimes increases to 10-15 cm / s. Due to low velocities, the currents are unstable, their picture is often disturbed by the action of winds. Storm winds cause strong wind currents with speeds of up to 150 cm / s, which quickly diminish after a storm.

Because of the insignificant connection with the ocean, the tides in B. m are weakly expressed, the height is 0.1–0.2 m. The surge fluctuations of the level reach significant values (at the tops of the bays, up to 2 m). The combined effect of wind and abrupt changes in atmospheric pressure causes 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 westerly winds sometimes cause an increase 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 B. m. 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 sea, the surface water temperature is 1-3 ° C, in bays and bays below 0 ° C. The salinity of water on the surface is 11 ‰ at the outlet from the Danish straits, 6–8 ‰ in the central part of the sea, 2 ‰ or less in the tops of the Gulfs of Bothnia and Finland.

B. m. Refers to the so-called. brackish basins, in which the temperature of the highest density is higher than the freezing point, which leads to an intensification of the formation process sea ice... Ice formation begins in November in bays and off the coast, 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 (stationary) ice reaches 1 m, drifting - from 0.4 to 0.6 m. Ice melting begins at the end of March, spreads from the southwest to the northeast, and ends in June.

Research history

The first information about B.'s researches of m is connected with the Normans. All R. 7 c. they entered the Gulf of Bothnia, opened Åland Islands, in the 2nd floor. 7-8 centuries reached west coast The Baltic states, discovered the Moonsund archipelago, first penetrated the Gulf of Riga, in the 9-10th centuries. used for trade and pirate activities the coast from the mouth of the Neva to the Gdansk Bay. Hydrographic and cartographic work was carried out by the Russians in the Gulf of Finland at the beginning of the 18th century. In 1738, F.I.Soimonov published an atlas of B. m., Compiled from domestic and foreign sources. All R. 18th century long-term research was carried out by A.I. 1880s were performed by S.O. Makarov. Since 1920, hydrological work was carried out by the Hydrographic Directorate of the Navy, the State Hydrological Institute (Leningrad), and from the 2nd half. 20th century extensive comprehensive research was 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 are made up of freshwater species inhabiting the freshened waters of the bays (crucian carp, bream, pike, pike perch, chub), the Baltic herd of salmon and purely marine species prevalent mainly in the central part of the sea (cod, herring, smelt, vendace, sprat). In the Baltic Sea, the fishery is carried out for herring, sprat, herring, smelt, river flounder, cod, perch, etc. A unique object of fishing is eel. Placers of amber are widespread on the coast of Byelorussia; 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 importance of B. of m as a transport artery is great. Large transportation of liquid, bulk and general cargo is carried out along the B. m. A significant part of the foreign trade of Denmark, Germany, Poland, Russia, Lithuania, Latvia, Estonia, Finland, and Sweden is carried out through the B. m. 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), cellulose 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.

A gas pipeline (2 strings, 1220 mm in diameter each) “Nord Stream” has been laid along the bottom of the B. m. Between Russia and Germany. Passes from the Portovaya Bay near Vyborg ( Leningrad region) to Lubmin near Greifswald (Germany, federal land Mecklenburg-Western Pomerania); length 1224 km (the longest underwater gas pipeline in the world). The throughput (capacity) of the gas pipeline is 55 billion cubic meters of gas per year. The maximum sea depth in the places where the pipe passes is 210 m. 148 sea vessels... The total mass of steel used in the construction of the gas pipeline is 2.42 million tons.

During the preparatory phase, Nord Stream spent approx. 100 million euros. In 1997, preparatory work began on the construction of the offshore section: scientific research was carried out, on the basis of which an approximate route of the gas pipeline was determined. In 2000, by the decision of the European Union Commission on Energy and Transport, the project was assigned the status of TEN ("Trans-European Networks"). The construction of the gas pipeline began on April 9, 2010. The first string of the gas pipeline was put into operation on November 8, 2011, the second - on October 8, 2012.

In September 2015, a Shareholders Agreement was signed on the implementation of a project called Nord Stream 2. On July 8, 2016, Nord Stream 2 completed a tender for the selection of a contractor for the application of a concrete weight coating on the gas pipeline pipes.

344 vessels with a total deadweight tonnage of 1,196.6 thousand tons are registered in the ports of the Baltic Sea. Largest ports: St. Petersburg, Kaliningrad, Vyborg, Baltiysk (all - Russia); Tallinn (Estonia); Riga, Liepaja, Ventspils (all - Latvia); Klaipeda (Lithuania); Gdansk, Gdynia, Szczecin (all - Poland); Rostock - Warnemünde, Lubeck, Kiel (all - Germany); Copenhagen (Denmark); Malmo, Stockholm, Luleå (all - Sweden); Turku, Helsinki and Kotka (all Finland). Developed sea passenger and ferry services: Copenhagen - Malmö, Trelleborg - Sassnitz (rail ferries), Nortelier - Turku (car ferry), etc. Crossings through the straits: Great Belt (1998; length 6790 m), Little Belt (both - Denmark; 1970; 1700 m), Øresund (Denmark - Sweden; 2000; 16 km); it is planned to build a ferry across the Femer Strait (Denmark - Germany; 2018; 19 km). Due to the shallow depths, many places are inaccessible to ships with a significant draft, but the largest cruise ships pass through the Danish straits into the Atlantic Ocean.

On the south and southeast coasts, there are many resort places: Sestroretsk, Zelenogorsk, Svetlogorsk, Pionersky, Zelenogradsk, Curonian Spit (all - Russia); Parnu, Narva-Jõesuu (both - Estonia); Jurmala, Saulkrasti (both - Latvia); Palanga, Neringa (both - Lithuania); Sopot, Hel, Kolobrzeg, Koszalin (all - Poland); Ahlbeck, Binz, Heiligendamm, Timmendorf (all - Germany); Öland Island (Sweden).

Ecological state

The B. m., Which has a difficult water exchange with the World Ocean (water renewal lasts about 30 years), is surrounded by industrially developed countries and is experiencing an extremely intense anthropogenic load. The main environmental problems are associated with the burial of chemical weapons at the bottom of the sea, the discharge of wastewater from large cities into the sea, the washout of chemical fertilizers used in agriculture, and especially with shipping - one of the most intense in the world (mainly oil tankers). After the entry into force in 1980 of the Convention for the Protection of the Marine Environment of Biology, the ecological situation improved due to the commissioning of a large number of wastewater treatment facilities, a reduction in the use of chemical fertilizers, and control over the technical condition of ships. Decreased concentration of toxic substances such as DDT and polychlorinated biphenyl, petroleum hydrocarbons. The content of dioxins in the Baltic herring is 3 times lower than the MPC, the population of the gray seal has recovered. The question of giving the B. m. The status of a particularly vulnerable sea area is being considered.

Window to Europe

The Baltic Sea is inland sea basin of the Atlantic Ocean and is located in a shallow depression between the Scandinavian Peninsula and the European continent. The system of the Danish Straits, through the North Sea, connects the Baltic Sea with the ocean area.

The surface area is 386 thousand square kilometers, the average depth is 71 m, the maximum depth is 459 m (the Landsortsjupet basin south of Stockholm).

The ancient Slavs called this sea Varangian.

As a result of studying the bottom topography and the nature of the soils, scientists came to the conclusion that in the preglacial period there was land on the site of the Baltic Sea. Then, during the Ice Age, the depression, which now houses the sea, was filled with ice, the process of melting which led to the formation of a lake with fresh water.

About 14 thousand years ago, this lake merged with the ocean as a result of the subsidence of land areas - the lake turned into a sea. Then, after another uplift of the land in the region of Central Sweden, the connection between the sea and the ocean was severed, and it again turned into a closed lake-type body of water.

About 7 thousand years ago, another sinking of the land took place in the area of the modern Danish straits and the connection of the lake with the Atlantic was resumed.

Subsequent fluctuations in land level led to the formation of the modern Baltic Sea.

The rise of land in the area continues to this day. Thus, in the area of the Gulf of Bothnia, the bottom rise is approximately 1 m in 100 years.

Climate in the maritime region is temperate, characterized by small seasonal temperature fluctuations, frequent precipitation in the form of rains, fogs and snow.

Temperature surface water reaches +20 degrees C in summer. As you move to the north, the water is cooler and in the Gulf of Bothnia does not warm up above +9 - +10 degrees C. In winter, the water cools down to freezing point and the northern bays of the sea are covered with ice. The central and southern regions are usually ice-free, but in extremely cold winters, the sea can be completely covered with ice.

Water strongly freshened in the sea, especially in areas remote from the Danish straits. The reason is the numerous rivers and streams (almost 250) flowing into the sea.

Among the major rivers one can note the Neva, Narva, Vistula, Kemijoki, Zapadnaya Dvina, Neman, Odra.

Currents in the sea they form a cyclonic circulation, often their direction and speed are corrected by the winds.

Tides the sea is very low - 5-10 cm, however, wind surges, especially in narrow bays, can exceed 3-4 meters.

Coastline The Baltic Sea is heavily indented. There are many large and small bays, bays, capes, and spits. The northern shores are rocky; as you move to the south, rocks and stones are replaced by sand-pebble mixtures and sand. Here the shores are low and flat.

Islands of continental origin, especially many small rocky islets in the northern part of the sea. Large islands: Gotland, Bornholm, Sarema.

Bottom relief sea complex. There are many uplifts and depressions that have appeared as a result of the activity of glaciers, river beds, and land fluctuations. However, the elevation differences are small - the sea is shallow.

Animal world The Baltic Sea is relatively poor in represented species. A feature of the sea fauna is the distribution of freshwater and marine animal species in different regions. In the northern, more fresher areas, especially near river mouths, there are mainly freshwater animals and species that easily tolerate water desalination. Closer to the Danish straits, the sea water is much saltier, so many typical marine life can be found here. The general species composition of the sea is scarce, but rather rich in quantitative terms.

The poverty of the sea fauna is also explained by its youth, because in the form that it has now, its age is estimated only five thousand years. Scientists predict that another 5,000 years will pass, and the Baltic Sea will again lose its connection with the ocean and turn into a large fresh lake... Many forms of marine life in such a short time simply did not have time to adapt to the local conditions of existence.

Nevertheless, the quantitative composition of the animals living in the Baltic Sea is quite large.

Bottom animal species are represented mainly by worms, gastropods and bivalve molluscs, small crustaceans and bottom fish - flounder, gobies. In some places you can find a shaggy-hand crab - an alien from the North Sea and has taken root here. Near the Danish straits, there is even a giant among jellyfish - cyanea. And another type of jellyfish - eared aurelia in the Baltic Sea is found almost everywhere. Small schooling fish - three-spined stickleback, Baltic sprat.

In the desalinated areas of the sea, there are many river fish: roach, perch, pike, bream, ide, pike perch, anadromous whitefish, burbot, etc.

In the baltic sea hunt such valuable fish as herring (about half of the total fish catch), sprat (sprat), salmon, eel, cod, flounder.

Marine mammals in the Baltic Sea there are only three species of seals: the gray seal (tyvyak), the common seal (seal), and the common porpoise, which belongs to toothed cetaceans.

Shark in the Baltic Sea, they are represented only by the ubiquitous katrana - a small prickly shark, which is dangerous to humans only by its spines on its dorsal fins. But these fish are not settled in all areas of the sea - too freshened and shallow areas are not suitable for them to live.

However, in the area of the Danish Straits, which connect the Baltic with the North Sea, other predators are sometimes found - herring sharks. No such guests have been registered on the Russian shores of the Baltic Sea.

In conclusion, I would like to note that at present the Baltic Sea is intensively polluted by various chemical and biochemical effluents, as well as microelements contained in precipitation. This leads to the mass death of microflora and microfauna, which in large quantities settle to the bottom and are processed by bacteria into hydrogen sulfide. And hydrogen sulfide has a detrimental effect on all living organisms in the bottom layer of water. If urgent measures are not taken, the number of aquatic animals in the sea will decrease significantly.

THE BALTIC SEA (Late Latin - Mare Balticum, among the ancient Slavs - the Varangian Sea or Sveiskoe), the inland sea of the Atlantic Ocean, between the Scandinavian Peninsula and the continental shores of North-Western 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. The maritime border of the Baltic Sea runs along the southern entrances of the Øresund, Great Belt and Little Belt straits. The area is 419 thousand km 2, the volume is 21.5 thousand km 3. The deepest 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 continent of Eurasia. The highly indented coastline forms numerous bays and coves. The largest bays: The Gulf of Bothnia, The Gulf of Finland, Gulf of Riga, Curonian Lagoon, Szczecin Bay, Gdansk Bay. The shores of the Baltic Sea in the north are high, rocky, mainly skerry and fjord types, in the south and southeast - mostly low-lying, lagoon type, with sandy and pebble beaches. The largest islands are: Gotland, Bornholm, Saaremaa, Muhu, Hiiumaa, Oland, Rügen. There are many small rocky islets - skerries located along the northern shores (there are over 6 thousand in the Aland Islands group).

Topography and geological structure of the bottom... The Baltic Sea is shallow, lies entirely within the shelf; depths of up to 200 m occupy 99.8% of its area. The Finnish, Bothnian and Riga bays are shallowest. 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 highly dissected relief. The bottom of its basin has depressions, delimited by the heights and bases of the islands: in the west - Bornholm (105 m) and Arkonskaya (53 m), in the center - Gotland (249 m) and Gdansk (116 m); north of the island of Gotland from northeast to southwest stretches the deepest depression - Landsort (up to 470 m). Numerous stone ridges, in the central part of the sea, there are ledges - continuation of klint, stretching from the northern coast of Estonia to the northern tip of the island of Öland, underwater valleys, glacial-accumulative relief forms 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 the large negative structure of the ancient platform - the Baltic syneclise. The extreme southwestern part of the sea is part of the young West European Platform. The bottom in the north of the Baltic Sea is composed mainly of Precambrian complexes overlapped by an intermittent cover of glacial and modern marine sediments. In the central part of the sea, the sediments of the Silurian and Devonian take part in the bottom structure. The ledges traced here are formed by the Cambrian-Ordovician and Silurian rocks. Paleozoic complexes in the south are overlain by a stratum of glacial and marine sediments of considerable thickness.

In the last ice age (in the late Pleistocene), the Baltic Sea basin was completely covered 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 was connected to the ocean, and the basin was filled with sea waters. 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. In the northern part of the Baltic Sea, uplift continues, the rate of which reaches 1 cm per year.

Bottom sediments at depths of more than 80 m are represented by clayey silts, under which there is strip clay on glacial deposits, at shallower depths silt is mixed with sand, and sands are widespread in coastal areas. There are boulders of glacial origin.

Climate... The Baltic Sea is characterized by a temperate maritime climate with features of continentality. Its seasonal features are determined by the interaction of baric centers: the Icelandic minimum and the Azores maximum in the west and the Siberian maximum in the east. Cyclonic activity reaches its highest intensity in the autumn-winter months, when cyclones bring cloudy, rainy weather with strong westerly and southwesterly winds. The average air temperature in February is 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 into the Baltic region lowers the temperature to -35 ° C. In summer, westerly winds also blow, but of little force, bringing cool, wet weather from the Atlantic. The air temperature in July is 14-15 ° С in the Gulf of Bothnia and 16-18 ° С in the rest of the sea. Rare inflows of warm Mediterranean air cause short-term temperature rises up to 22-24 ° С. Annual precipitation ranges from 400 mm in the north to 800 mm in the south. The largest number of foggy days (up to 59 days a year) is observed in the south and 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 freshwater supply 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. Fresh runoff is distributed unevenly throughout the territory. The Gulf of Bothnia receives 181, the Finnish - 110, the Riga - 37, and the central part of the Baltic Sea - 112 km 3 per year. The amount of fresh water supplied with atmospheric 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 current leave the Baltic Sea for the North Sea, and salty North Sea water with a bottom current enters through the straits from the North Sea. Strong westerly winds usually increase the inflow, and easterly - the flow 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 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, 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. The renewal and ventilation of bottom waters is highly dependent on the North Sea water supply, which is subject to interannual variability. With the reduction of the inflow of salt water into the Baltic Sea at great depths and in the depressions of the bottom relief, conditions are created for the appearance of freezing phenomena. Seasonal changes in water temperature cover the layer from the surface up to 50-60 m and usually do not penetrate deeper.

Wind waves develop especially strongly in the autumn-winter time with prolonged and strong southwestern winds, when waves with a height of 5-6 m and a length of 50-70 m are observed. The highest waves are observed in November. In winter, sea ice prevents the development of excitement.

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

Due to the insignificant connection with the ocean, tides in the Baltic Sea are weakly expressed, 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 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 the Gulf of Finland. Seiche waves with westerly surge winds sometimes cause an increase 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 of a catastrophic nature: 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 the southern regions it reaches 20 ° C. In February, in the open part of the sea, the water temperature on the surface is 1-3 ° С, in bays and bays below 0 ° С. 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 in the tops of the Gulfs of Bothnia and Finland.

The Baltic Sea belongs to the so-called brackish basins, in which the temperature of the highest density is higher than the freezing point, which leads to an intensification of the sea ice formation process. Ice formation begins in November in bays and off the coast, later in the open sea. In severe winters, the ice cover occupies the entire northern part of the sea and the coastal waters of its central and southern parts. The thickness of fast-ice (stationary) ice reaches 1 m, drifting - from 0.4 to 0.6 m. Ice melting begins at the end of March, spreads from the southwest to the 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 the Gulf of Bothnia, discovered the Aland Islands, in the 2nd half of the 7-8th centuries they reached the western coast of the Baltic, discovered the Moonsund archipelago, first entered the Gulf of Riga, in the 9-10th centuries they used the coast for trade and pirate activities from the mouth of the Neva to the Gdansk Bay. 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, A.I. Nagaev carried out many years of research, who drew up a detailed pilot of the Baltic Sea. The first deep-water hydrological studies in the mid-1880s were carried out by S.O. Makarov. Since 1920, hydrological work has been carried out by the Hydrographic Directorate of the Navy, the State Hydrological Institute (Leningrad), and since the second 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 are made up of freshwater species inhabiting the freshened waters of the bays (crucian carp, bream, pike, pike perch, chub), the Baltic herd of salmon and purely marine species prevalent mainly in the central part of the sea (cod, herring, smelt, vendace, sprat). In the Baltic Sea, the fishery is carried out for herring, sprat, herring, smelt, river flounder, cod, perch, etc. A unique object of fishing 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 a transport artery. Large carriages of liquid, bulk and general cargoes are carried out in 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 the ports of Russia and from the Atlantic Ocean), coal (from Poland, Russia), timber (from Finland, Sweden, Russia), cellulose 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 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, Lubeck, Kiel (Germany), Copenhagen (Denmark), Malmo , Stockholm, Luleå (Sweden), Turku, Helsinki, Kotka (Finland). In the Baltic Sea there are sea passenger and ferry connections: Copenhagen - Malmö, Trelleborg - Sassnitz (rail ferries), Nortelier - Turku (car ferry), etc. There are many resort places on the southern and southeastern coasts.

Ecological state. The Baltic Sea, which has a difficult water exchange with the World Ocean (water renewal lasts about 30 years), is surrounded by industrially developed countries and is experiencing an extremely intense anthropogenic load. The main environmental problems are associated with the burial of chemical weapons at the bottom of the sea, the discharge of wastewater from large cities into the sea, the washout of chemical fertilizers used in agriculture, and especially with shipping - one of the most intense in the world (mainly oil tankers). After the entry into force of the Convention for the Protection of the Marine Environment of the Baltic Sea in 1980, the ecological situation has improved due to the commissioning of a large number of wastewater treatment plants, a reduction in the use of chemical fertilizers, and control over the technical condition of ships. Decreased concentration of toxic substances such as DDT and polychlorinated biphenyl, petroleum hydrocarbons. The content of dioxins in the Baltic herring is 3 times lower than the MPC, the population of the gray seal has recovered. The issue of granting the status of a particularly vulnerable sea area to the Baltic Sea 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 of the Atlantic Ocean. M., 1986; Pushcharovsky Yu. M. Atlantic tectonics with elements of nonlinear geodynamics. M., 1994; Hydrometeorology and Hydrochemistry of the USSR Seas. SPb., 1994. T. 3. Issue. 2; Zalogin B.S., Kosarev A.N. M., 1999.

The Baltic Sea is a shallow sea. The average depth is 60 meters. The greatest depth is 459 meters (on the Swedish side).

The Baltic Sea is a young sea. It was formed about 10,000 years ago, after the last glaciation, when the ice receded.
The Baltic Sea is like a river with two branches (the Gulf of Finland and the Gulf of Bothnia). Geological studies have made it clear that there was a river (Eridanos) in the area before the Pleistocene. By the time of the interglacial, the riverbed turned into a sea, and the basin was named Eemian - the Sea of Eem.
The Baltic Sea is an inland sea. The length of the Baltic Sea is approximately 1,610 km (1,000 mi) in length, 193 km (120 mi) in width. The volume of water is about 21,700 cubic kilometers. Coastline approximately 8,000 km (4,968 mi)
The Baltic Sea is the world's largest body of brackish fresh water. The fact is that the sea was not formed from a collision or fracture of plates, but it is a glacial reclaimed river valley, which explains its relative freshwater content.
The salinity of the Baltic is much lower than that of the ocean water, due to the abundant river runoff from the adjacent lands. Fresh water flows into the sea from two hundred rivers. Runoff contributes to the exchange of water about one fortieth of its total volume per year.
The area of the Baltic Sea is about 400,000 km², which is 0.1% of the total area of the world's oceans the globe... The catchment area of the Baltic Sea is about four times the surface area of the sea itself.
We list 9 Baltic countries:, Poland, Russia, Sweden,.
The Baltic Sea has narrow junctions with the rest of the oceans, making tidal movements minimal.
The Baltic Sea is geographically located between 53 - 66 degrees. north latitude and 20 - 26 degrees. east longitude. In addition to the mainland of Europe, the Scandinavian Peninsula and the Danish islands belong to the Baltic Sea.
Skagen, Denmark is where the Baltic and North Seas meet. Due to the very different water densities and chemical differences, the two seas do not like to mix. As a result, they create the most amazing natural phenomenon - two bodies of water fight against each other, side by side.
From the Baltic Sea, the route lies through the strait (, Great Belt and Small Belt), then through the strait and.
The Baltic Sea is connected by artificial waterways with the White Sea Canal, and with the German Bay of the North Sea through the Kiel Canal.
In winter, ice binds about half of the surface area of the Baltic Sea. The ice-covered area includes Väinameri (a strait in Estonia, near the Moonsund archipelago). In the central part, the Baltic Sea, as a rule, does not freeze, with the exception of sheltered bays and shallow lagoons (such as the Curonian Lagoon).
Since 1720, there have been cases when the entire Baltic Sea froze over: a total of 20 times - the most recent case was in early 1987. Typical ice thickness in the northern regions is about 70 centimeters of landfast sea ice.
The first to call the sea the Baltic (Mare Balticum) was the eleventh century German chronicler Adam of Bremen. The origin of the name can be speculatively associated with the Germanic word "belt", Latin balteus (belt) - the sea stretches through the land like a belt. Or it is the influence of the name of the legendary Baltic island (Balcia), mentioned in the natural history of Pliny the Elder. Pliny refers to Pytheas and Xenophon, an island called Basilia ("kingdom" or "royal"). Baltia can also be derived from the word "ribbon". Or the name comes from the Proto-Indo-European root "BHEL", which means white. This root and its basic meaning have been preserved in Lithuanian (like BALTAS) and in Latvian. The name of the sea is associated with different forms of water (ice and snow are originally white).

Some Swedish historians believe that the name comes from the god Balder from Scandinavian mythology.
In the Middle Ages, the sea was known by various names. The name Baltic Sea became dominant only in 1600. The use of "Baltia" and other similar terms appeared already in the 19th century.
During Roman times, the Baltic Sea was known as the Suebicum Sea or the Sarmaticum Sea. Tacitus, in his 98 AD Agricola / Germania, described that the Svevikum Sea got its name from the Sueva, as the tribes called the spring months when the sea ice broke and melted. The Sarmatian Sea was called because Eastern Europe in those days inhabited by the Sarmatian tribes. Jordanes called this sea the Germanic Sea in his work Getica.
During the Viking Age, the Scandinavians called it “ By the eastern sea"(Austmarr). This name appears in Heimskringla and in the Scandinavian chronicle Sörla. Saxon Grammaticus wrote down in the Gesta Danorum the name Gandwick from the ancient Norse "wiki" - "bay". This means that the Vikings did not view the Baltic Sea as a sea, but as an outlet to the open sea. The name "Grandvik" is repeated in one English translation- Acts of the Danes.
The northern part of the Baltic Sea is known as the Gulf of Bothnia. The more southerly basin of the bay is called Selkameri, and directly south of it is the Åland Sea. The Gulf of Finland connects the Baltic Sea with St. Petersburg. The Gulf of Riga is located between the Latvian capital Riga and the Estonian island of Saaremaa.
In the south, the Gulf of Gdansk - east of the Hel Peninsula on the Polish coast and in the west of the Sambia Peninsula. Pomeranian Bay is located north of the island of Usedom and Wolin, east of Rügen. Between Falster and the German coast lies the Mecklenburg Bay and the Lübeck Bay. The western part of the Baltic Sea is the Kiel Bay.
About 48% of the region is covered with forests (and Finland also accounts for most of the forests). About 20% of the land is used for agriculture and pasture. About 17% of the pool is not used - open land... Another 8% are wetlands.
The Baltic is home to about 85 million people - 15% within 10 km from the coast, 29% - within 50 km from the coast. About 22 million people live in cities.
The Baltic Sea is rich in amber, especially off the southern shores. The first mentions of amber deposits on the Baltic Sea coast appeared in the 12th century. except fishing and amber, bordering countries traditionally supply timber, tree resin, flax, hemp and furs. Sweden has thrived in mining since the early Middle Ages, especially for iron ore and silver. All of this has provided the region with a rich trade since Roman times.
In the early Middle Ages, the Vikings of Scandinavia fought for power over the sea with the Slavic tribes of Pomerania. The Vikings used the rivers for trade routes to eventually make their way to.
Three Danish straits - the Great Belt, Little Belt and Oersund (Öresund / Sound), connect the Baltic Sea with the Kattegat and Skagerrak straits in the North Sea.
The bays of the Baltic Sea are the Bothnian, Finnish, Riga, Greifswald, Matsalu, Möcklenburg, Kiel, Kaliningrad, Pomorsky, Pärnu, Untervarnov, Lumparn, Szczecin and the Gulf of Gdansk. The Curonian Lagoon (freshwater) is separated from the sea by a sand bar.
The fauna of the Baltic Sea is a mixture of marine and freshwater species. Among marine fish - cod, herring, hake, flounder, stickleback, halibut. Examples of freshwater species are perch, pike, whitefish and roach.
Populations of Atlantic white dolphins and porpoises are endangered. Outside the range, species such as minke whales, bottlenose dolphins, beluga whales, killer whales and the beaked whale family have become rare visitors to the Baltic waters. In recent years, very few fin whales and humpback whales have migrated to the Baltic Sea.
Shipbuilding at the shipyards of the Baltic Sea. The largest shipyards are Gdansk and Szczecin (Poland); Kiel (Germany); Karlskron and Malmö (Sweden); Rauma, Turku and Helsinki (Finland); Riga, Ventspils and Liepaja (Latvia); (Lithuania); (Russia).
There are many sunken ships in the Baltic Sea. According to conservative estimates, there are about 100,000 of them. Ships that are more than a thousand years old have been found. A Stone Age boat made of hollow wood is the oldest ship discovered in the Baltic - dated 5,200 BC.
In 2010, an international team of scientists in the Baltic Sea investigated a 17th century shipwreck at a depth of 130 meters using robots and echo sounders, never before used in deep sea archeology.
The salinity of the Baltic Sea is only 0.06-0.15% (in comparison with the salinity of 3.5% in large oceans), making it unusable for the Teredo Navalis worm. This is the main reason why wooden shipwrecks survive in the Baltic Sea. In the Baltic Sea, there are also archaeological traces of the inhabitants of the Stone Age - there are entire forests under the water, which were drowned when the glaciers of the last Ice Age retreated, about 15,000 years ago.
Gotland is the most big Island Baltic. Gotland is a Swedish province. Visby is the capital of Gotland, once a Hanseatic city with a medieval center, which has become a national treasure in Sweden. Visby is the oldest surviving city wall in Northern Europe. There are over 200 medieval stone buildings inside.
In 1628 the Swedish warship Vasa sank on its maiden voyage near Stockholm harbor. 35 years later, a group of daring submariners managed, using a primitive diving bell, to raise about fifty guns (cannons) of this ship. And only in 1961, 333 years after his death, Vasu was raised from a depth of 30 meters. The Vasa Museum is now one of the most popular tourist places Sweden.
The worst maritime disaster in the world and the only one of its kind in the entire history of mankind happened in the Baltic Sea - this is the death of the passenger liner Wilhelm Gustloff - more than 10,000 people died. The disaster took place on January 30, 1945 in the southern part of the Baltic. was torpedoed by a Soviet submarine.
A ghost ship discovered by accident in 2003 while searching for a Swedish spy plane. This discovery was made public in 2007. The Swedish scientist came to the conclusion that the shipwreck is really unique and has great historical significance. This is a typical Dutch shipbuilding ship of the 17th century, probably built in 1650. In Dutch the type of ship is called fluyt. 26 meters long, 8 meters wide. Its carrying capacity is 100 units (about 280 tons). Thanks to the three-dimensional model of the ship, scientists can now reconstruct the outer and inner parts of it. This gives a lot of new knowledge about shipping and trade in that historical period.