What does the Baltic Sea border with? Baltic Sea: salinity, depth, coordinates and interesting facts

Extreme northern point Baltic Sea is located near the Arctic Circle (65°40" N), the southernmost one is near the city of Wismar (53°45" N).

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

Sea surface area (without islands) is 415 thousand km². The volume of water is 21.5 thousand km³.

Geological history

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

Physiographical sketch

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

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

The major rivers flowing into the Baltic Sea are the Neva, Narva, Western Dvina (Daugava), Neman, Pregolya, Vistula, Oder and Venta.

Bottom relief

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

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

Hydrological regime

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

In 2003, 21 incidents were recorded in the Baltic Sea. chemical weapons into fishing nets - all are clots of mustard gas with a total weight of approximately 1005 kg.

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

Natural resources

Development of deposits may be hampered by strict environmental requirements associated with insignificant water exchange between the sea and the ocean, anthropogenic pollution water runoff from the territory of coastal states, contributing to increased eutrophication.

laid along the bottom of the Baltic Sea

The Baltic Sea, like a real European one, washes the borders of several states at once. If previously many principalities and empires fought for the right to own the ports located on it, today the situation in the water area is calm. Nine countries have access to the shores of the Baltic Sea: Russia, Estonia, Lithuania, Latvia, Poland, Denmark, Sweden, Germany and Finland.

The Baltic Sea can be called a typical inland sea. It is located in the Northwestern part of Eurasia and is connected to the Atlantic Ocean in the North Sea through the Denmark Straits. The size of the water area is large enough for Europe - 419,000 sq.m, despite the fact that average depth is 51 m ( maximum rate- 470 m). The Baltic Sea is full of water due to the large number of rivers that flow into it - the world-famous Vistula, Neman, Neva and Daugava. The largest among them (bringing more water into the pool) is our Neva.

As for the shores of the Baltic Sea, relative to the mainland of the planet they stretch from southwest to northeast. The widest place on land is called the stretch of land from St. Petersburg to Stockholm - this is almost 650 km of continuous beach.

It is fair to note that the Baltic was not always under the sphere of Russian influence. These northern shores have long attracted kings and appanage princes feudal states. Quite often, commanders together with armies tried to get a tasty morsel seashore, but I couldn’t get what I wanted. One has only to remember the bloody attempts of Tsar Ivan the Terrible and the failed Livonian War he started.

Fortune smiled on Russia only at the beginning of the 18th century. Northern War, which covered almost the entire northern and eastern parts of Europe, allowed Peter the Great to get his piece of the Gulf of Finland and begin the process of “Europeanization” of the Russian people.

Cities on the Baltic Sea in Russia

Today, the Baltic Sea is considered not only a strategic area, but also an excellent resort for residents of the country and neighboring regions. There's enough here cold water, sometimes capricious and violent, which, however, does not scare off the tourists who come here every summer.

Kaliningrad

(Kaliningrad port terminal, located in the Kaliningrad Bay)

The central city of the region, as is known, was previously called Keninsberg. Today it is large city at sea, which managed to preserve the outlines of German prosperity, while acquiring a typical Russian appearance. Today people come here not only to the grave of the great Kant, but also for medical mineral waters and sandy beaches.

Svetlogorsk and Zelenogradsk

Two typical resort towns that differ only in size. The first one is larger and more touristy. A large number of hotels and restaurants for every taste, local residents have long adapted to the needs of guests and offer a quiet and cozy holiday on the seashore.

In addition, the region has huge amount small villages in coastal zone. Many of them mine amber and offer excursions to old breweries. Today, the Russian shores of the Baltic Sea have been completely Russified and the only reminders of the time when the lands belonged to Europe are the peaked roofs of churches and the two-story houses with red tiles stretching along the shore.

The Baltic Sea is deeply cut into the Northwestern part of Eurasia. It is an inland sea connected to North Sea Atlantic Ocean system of straits Oresund (Sound), Great Belt, Little Belt, known as common name Danish Straits. They pass into the deep and wide straits of Skagerrak and Kattegat, which already belong to the North Sea, which directly communicates with the Atlantic Ocean.

The area of ​​the Baltic Sea is 419 thousand km2, volume - 21.5 thousand km3, average depth - 51 m, greatest depth- 470 m.

About 250 rivers flow into the Baltic Sea. Largest rivers- Vistula, Oder, Neman, Daugava, Neva. Largest quantity The Neva brings water per year - an average of 83.5 km3.
The Baltic Sea stretches from southwest to northeast, and its greatest length equal to 1360 km. The most wide place sea ​​at 60° N. sh., between St. Petersburg and Stockholm, it stretches for almost 650 km.

The bottom topography of the Baltic Sea is uneven. The sea lies entirely within the shelf. The bottom of its basin is indented by underwater depressions, separated by hills and the bases of islands.

The Baltic Sea is characterized by a large extent coastline. It has many bays, bays and large number islands. The sea is a collection of separate basins: the zone of the Danish Straits, the open or central part of the sea and three large bays - Bothnian, Finnish and Riga, which account for almost half of the sea's water area.

Numerous islands of the Baltic Sea are located both off the mainland coasts and in the open sea; in some parts of the sea the islands are grouped in large archipelagos, in others they stand alone.
The largest of the islands: Danish - Zealand, Funen, Lolland, Falster, Langeland, Mön, Bornholm; Swedish - Gotland, Öland; German - Rügen and Fehmarn; Estonian - Saaremaa and Hiiumaa.

The shores of the northern and southern half of the sea differ sharply in character. The skerry coasts of Sweden and Finland are indented with small bays and bays, framed by islands composed of crystalline rocks. They mostly low, sometimes bare, and in some places overgrown coniferous forest. Southern Shores are low-lying, consist of sand and have large number shallows. In some places along the coast there are chains of sand dunes, and long spits protrude into the sea, forming large lagoons desalinated by river runoff. The largest of these shallow water bays are the Curonian and Vistula bays.

Bottom sediments The Baltic Sea is represented mainly by silt and sand. The soils of the Baltic Sea are characterized by stones and boulders, which are often found on the seabed. Sandy deposits are common in coastal areas. In the Gulf of Finland most The bottom is covered with sands with isolated patches of silts, occupying small depressions and forming a field of sediments in the delta front of the Neva River, somewhat elongated along the strike of the bay. Construction of a dam that fenced off open sea a significant part of the water area, significantly changed the composition and distribution of sediments that existed in natural conditions.

Climate The Baltic Sea is a sea of ​​temperate latitudes with continental features. The peculiar configuration of the sea and its considerable length from north to south and from west to east create differences in climatic conditions in different areas of the sea.

The Icelandic low, as well as the Siberian and Azores anticyclones, have the most significant influence on the weather. The nature of their interaction determines the seasonal characteristics of the weather. In autumn and especially winter time The Icelandic minimum and the Siberian maximum interact intensively, which enhances cyclonic activity over the sea. In this regard, in autumn and winter, deep cyclones often pass through, bringing with them cloudy weather with strong southwestern and western winds.

During the coldest months - January and February - average temperature air in the central part of the sea is –3°С in the north and –5...–8°С in the east. With rare and short-term intrusions of cold Arctic air associated with the intensification of the Polar High, the air temperature over the sea drops to –30°C and even to –35°C.

In summer, predominantly western, northwestern, weak to moderate winds blow. They are associated with the cool and humid summer weather characteristic of the sea. The average monthly temperature of the warmest month is 14–15°C in the Gulf of Bothnia and 16–18°C in other areas of the sea. Hot weather is rare. It is caused by short-term influxes of heated Mediterranean air.

Water temperature conditions Baltic Sea in various parts they are not the same and depend not only on the geographical location of the place, but also on the meteorological and hydrological features of the area. The greatest significance for temperature regime The Baltic Sea has surface heating by the sun's rays, runoff river waters and the influx of deep ocean waters. This determines the general picture of the temperature conditions of the sea. In the surface layers, the water temperature varies within wide limits. At depths exceeding 50 meters, the water temperature all year round is kept within 3–4°С in the southern part of the sea and around zero in the northern Bothnian region.

IN summer months The water temperature at the surface is generally close to the air temperature. Along the eastern shores, the water temperature is higher due to the influence of heated land masses lying to the south; along the western, Swedish shore, it is lower due to the flow of cold water from the north, from the Gulf of Bothnia. In winter, on the contrary, eastern sections the seas are colder than the western ones; they are exposed to the influence of the cooled land masses of the continent, and the western parts of the sea during this period experience a regular supply of warm air masses Atlantic.

Limited water exchange with the North Sea and significant river flow cause low salinity. On the sea surface it decreases from west to east, which is associated with the predominant influx of river waters from the eastern Baltic. In the northern and central regions of the basin, salinity decreases slightly from east to west, since in the cyclonic circulation salty waters are transported from south to northeast along the eastern coast of the sea further than along the western coast. A decrease in surface salinity can be traced from south to north also in the bays.

In almost the entire sea, a significant increase in salinity from the surface to the bottom is noticeable. The change in salinity with depth is essentially the same throughout the sea, with the exception of the Gulf of Bothnia. In the southwestern and partly central regions sea, it gradually and slightly increases from the surface to horizons of 30–50 m; below, between 60–80 m, there is a sharp layer of discontinuity (halocline), deeper than which the salinity again increases slightly towards the bottom. In the central and northeastern parts, salinity increases very slowly from the surface to horizons of 70–80 m; deeper, at horizons of 80–100 m, a halocline occurs, and then salinity increases slightly to the bottom. In the Gulf of Bothnia, salinity increases from the surface to the bottom only by 1–2‰.

In autumn-winter, the flow of North Sea waters into the Baltic Sea increases, and in summer-autumn it decreases somewhat, which leads to an increase or decrease in salinity, respectively. deep waters. In the autumn-winter season, salinity upper layers increases slightly due to a reduction in river flow and deviations during ice formation. In spring and summer, surface salinity decreases by 0.2–0.5‰ compared to the cold half of the year. This is explained by the desalinating influence of continental runoff and spring melting of ice. Except seasonal fluctuations Salinity in the Baltic Sea, unlike many seas of the World Ocean, is characterized by significant interannual changes. Salinity variability in the Baltic Sea is one of the most important factors regulating many physical, chemical and biological processes. Due to low salinity surface waters sea, their density is also low and decreases from south to north, varying slightly from season to season. Density increases with depth.

Most powerful wind waves observed in autumn and winter in open, deep areas of the sea with prolonged and strong south-west winds. Stormy winds of force 7–8 develop waves up to 5–6 m high and 3–4 m long. The largest waves occur in November. In winter with more strong winds education of high and long waves ice prevents. As in other seas northern hemisphere, surface circulation The waters of the Baltic Sea have a general cyclonic character.

Surface currents are formed in the northern part of the sea as a result of the confluence of waters emerging from the Gulf of Bothnia and the Gulf of Finland. The speed of constant currents in the Baltic Sea is very low and is approximately 3–4 cm/s. Sometimes it increases to 10–15 cm/s. The current pattern is very unstable and is often disturbed by the wind. The prevailing wind currents at sea are especially intense in autumn and winter, and during strong storms their speed can reach 100–150 cm/s.

The deep circulation in the Baltic Sea is determined by the flow of water through the Danish Straits. The inlet current in them usually extends to a horizon of 10–15 m. Then this water, being denser, sinks into the underlying layers and is slowly transported by the deep current, first to the east and then to the north.

Due to the high degree of isolation from the World Ocean, tides in the Baltic Sea are almost invisible. Tidal level fluctuations at individual points do not exceed 10–20 cm. In the seasonal course of the Baltic Sea level, two minimums and two maximums are clearly expressed. Lowest level observed in spring. With the arrival of spring flood waters, it gradually rises, reaching a maximum in August or September. After this the level decreases. A secondary autumn minimum is approaching. With the development of intense cyclonic activity westerly winds They push water through the straits into the sea, the level rises again and reaches a secondary, but less pronounced maximum in winter. The difference in level heights between the summer maximum and spring minimum is 22–28 cm. It is greater in the bays and less in the open sea.

Surge fluctuations in sea level occur quite quickly and reach significant values. IN open areas in the sea they are approximately 0.5 m, and at the tops of bays and bays they are 1–1.5 and even 2 m. Joint action wind and sudden change atmospheric pressure(during the passage of cyclones) cause seiche fluctuations in the level surface with a period of 24–26 hours. Level changes associated with seiches do not exceed 20–30 cm in the open part of the sea and reach 1.5 m in the Neva Bay. Complex seiche level fluctuations are one of the characteristic features regime of the Baltic Sea.

Catastrophic floods in St. Petersburg are associated with sea level fluctuations.
The Baltic Sea is covered in some areas ice. Ice forms earliest (around the beginning of November) in the northeastern part of the Gulf of Bothnia, in small bays and off the coast. Then shallow areas of the Gulf of Finland begin to freeze. Maximum development ice cover reaches in early March. By this time, the motionless ice occupies northern part The Gulf of Bothnia, the Åland skerries area and the eastern part of the Gulf of Finland. Floating ice is found in open areas of the northeastern part of the sea.

The main problems of the Baltic Sea are related to the gradual deterioration oxygen conditions deep layers of the sea, which is observed last decades. In some years, oxygen disappears completely at a depth of 150 m, where it forms hydrogen sulfide. These changes are a consequence of both natural changes in the environment, mainly temperature, salinity and water exchange, and anthropogenic impact, expressed mainly in an increase in the supply of nutrient salts in the form various forms nitrogen and phosphorus.

The importance of the Baltic Sea in national economy countries of the region and increasingly negative influence anthropogenic factors on the quality of the marine environment require urgent measures to guarantee the cleanliness of the sea.
Pollution enters the sea directly from wastewater or from ships, diffusely through rivers or the atmosphere. The bulk of pollutants are brought into the sea with the runoff of rivers (Neva, Vistula) both in a dissolved state and adsorbed in suspension. In addition, sources of pollution of the marine environment with oil products are the coastal cities, St. Petersburg, Kronstadt, Vyborg and, in to the greatest extent, - merchant and military fleets.

The greatest harm to the marine environment is caused by toxic substances (salts heavy metals, DDT, phenols, etc.), petroleum products, organic and biogenic substances. Every year from various sources About 300 tons of petroleum products enter the Gulf of Finland. The bulk of nitrogen compounds enter the sea diffusely, as well as sulfur compounds, which enter the marine environment mainly through the atmosphere. Toxic substances are discharged mainly by industry. Different character pollution complicates the fight for cleanliness of the marine environment and requires the implementation of a complex set of water protection measures.

Marine Environment Monitoring is first and foremost an organization systematic observations for physical, chemical and biological indicators of the marine environment at permanent representative points of the reservoir.
The quality of the marine environment of the Baltic Sea generally meets the requirements of water users, but near many large cities and industrial centers zones of contamination have formed. It is alarming that over the past decades the content of toxic substances in marine living organisms has increased by two orders of magnitude, which once again indicates the need to take urgent water protection measures. Accidental spills of oil products from tankers cause great harm. The monitoring results will make it possible to periodically check the state of the marine environment, i.e., identify the dynamics of sea pollution.

Two small sections of the seabed of the coastal part of the Baltic Sea belonging to Russia are sharply different in terms of geoecological situation. The most anthropogenic pressure is experienced internally, eastern part Gulf of Finland within the Leningrad region. The main zone of contamination was that part of the bay that is located east of Kotlin Island, between it and the Neva delta. This happened several years ago after the construction of a dam running from Kotlin Island to the northern and southern mainland shores. An important element geoecological situation in the eastern part of the Gulf of Finland are numerous underwater quarries for the extraction of construction raw materials, mainly sand, which may in the future pose a threat to the stability of the coastal part of the bottom and shores.