The Baltic Sea is the northern marginal body of water in Eurasia. It deeply cuts into the land, and due to this, it belongs to the internal type of water flows. The sea fills the waters of the Atlantic. It is located in Northern Europe. Baltic countries have access to the Baltic Sea. And also such states as: Denmark, Sweden, Finland, Germany, Russia and Poland. A stream connects to the ocean through the Danish Straits 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 strongly affects the flora and fauna, is filled with a huge amount of fresh water. Their constant source is rainfall. Salty 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.
The depth of the Baltic Sea is constantly within the same radius. Air masses can exert a strong influence on it. Off 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 pond is calm, and rarely when its waves are able to reach a height of 4 meters. Most storms in the fall, in November. Maximum fluctuations - 7-8 points. In winter, they practically cease, this is facilitated by ice.
The constant flow of the Baltic Sea is small. Within 10-15 cm / s. The maximum current during storms increases to 100-150 cm / s.
The tides of the Baltic Sea are almost invisible. This is facilitated, to a greater extent, by the isolation of the water stream. Their level varies within 20 meters. The maximum increase in water levels is in August and September.
A significant part of the coast is covered with ice from October to April. The southern part and the center of the sea do not freeze, but glaciers can drift along them during the thawing period (June-August).
The Baltic Sea is rich in natural resources. Oil reserves are being laid here, new fields are being developed. Large deposits of amber have also recently been found. The gas stream “Nord Stream” passes along the bottom of the sea.
And the Baltic Sea is rich in fish and seafood. In recent years, flow ecology has deteriorated significantly. Waters become clogged with toxins coming from large rivers. The presence of dumps from chemical weapons is also recorded.
Due to the shallow depth of the sea, shipping is not very developed here. Only light courts have the ability to cross a watercourse without problems. The largest ports of the 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 hospitals on the coastal part. These are the Russian resort cities of Svetlogorsk, Zelenogorsk, Sestroretsk, Latvian Jurmala, Lithuanian Neringa, Polish Koszalin and Sopot, German Albek and Bints.
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 from west to east, has an official indicator of 20 ppm at the beginning of the course. At a depth, this figure increases by 1.5 times.
Title
For the first time, the etymological name “Baltic” is found in a historical treatise of the 11th century. The earlier name of the sea is Varyazhskoe. That it is mentioned in the famous "Tale of Bygone Years."
Extreme points
Extreme points of the Baltic Sea:
- southern - Wismar (Germany), coordinates - 53 ° 45` s. W .;
- North - Arctic Circle coordinates - 65 ° 40` s. W .;
- East - 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 stretched from the southwest to the northeast for 1360 km. The greatest width is between the cities of Stockholm and St. Petersburg. It is 650 kilometers.
According to historical information, the Baltic Sea has existed for about 4 thousand years. At the same time, the most full-flowing river that flows into this body of water, the Neva (74 km), begins to exist. In addition to it, more than 250 rivers merge with the stream. The largest of them are Wisla, Oder, Narva, Neman, Western Dvina.
Some ports of the Baltic Sea lie on its large bays. 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 the Curonian lagoon. Due to the fact that the latter is separated from the sea by a sand 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 the inland mainland water bodies.
The islands
There are more than 200 islands of different sizes in the sea. They are unevenly located both near the coast and far from them. The largest Baltic islands - Zealand, Falster, Myeon, 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 the coast is low, with a sandy beach, which in some areas is represented by small dunes. A frequent occurrence on the young coast - sand spits, deeply crashing 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 powerful water flow from rivers, the Baltic Sea (the salinity of the reservoir is relatively small) is filled in excess with fresh water. It is distributed unevenly. Where the Baltic pond deeply enters the coast, the water is almost fresh, and the North Sea affects its salinity. This situation is not constant. 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 characteristic of the coastline, the largest number of ppm - at the bottom.
In the territory where the watercourse meets the straits in the west - salinity 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 is the lowest. It does not exceed a value of 3 ‰. A level of 6 to 8 ‰ is characteristic of the waters of the central part.
Also, seasonal distribution 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 melt rivers carry fresh water to the sea. And in autumn and winter, on the contrary, it increases due to the arrival of cold northern masses.
Changing sea salinity 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.