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Black Sea

Inland sea in southeast Europe, linked with the seas of Azov and Marmara, and via the Dardanelles strait with the Mediterranean; area 423,000 sq km/163,320 sq mi; maximum depth 2,245 m/7,365 ft, decreasing in the Sea of Azov to only 13.5 m/44 ft. It is bounded by Ukraine, Russia, Georgia, Turkey, Bulgaria, and Romania, and the rivers Danube, Volga, Bug, Dniester and Dnieper flow into it, keeping salinity levels low. Uranium deposits beneath it are among the world"s largest. About 90% of the water is polluted, mainly by agricultural fertilizers.

The Black Sea is Europe"s most polluted sea; rivers feeding it bring raw sewage, nitrates, phosphates, pesticides, heavy metals, and other pollutants from 13 countries. This is accelerating the natural accumulation at the bottom of the sea of a layer of hydrogen sulphide, ammonia, methane, and ethane, which is rising by 2 m/7 ft a year. Below a depth of 150 m/500 ft 90% of the water is anoxic (lacking in oxygen), mixing little with the surface water, and supporting little life. It constitutes the world"s largest mass of anoxic water and is caused by bacterial action on rotting vegetation.

In addition to pollution, the comb jellyfish Mnemiopsis leidyi has contributed significantly to a reduction in marine biodiversity. It entered the Black Sea in the early 1980s in ballast water from a US ship. Without predators it thrived, feeding on fish eggs and larvae. Fish catches were reduced by 90% in only six years. By 1990 the estimated biomass of the jellyfish peaked at 900 million tonnes.

20752

Флора и фауна Интересна особеност на Черно море е наличието на сероводород в концентрация 11-14 ml/l на дълбочина от 120-150 m до дъното, което прави невъзможно съществуването на живи същества, с изключение на някои анаеробни...     Още по темата

History of Black Sea About 50-60 million years ago, before the beginning of Tertiary Period, large oceanic basin stretched out from west to east across Southern Europe and Central Asia connecting the Atlantic Ocean and the Pacific Ocean. It was the salty Tethys Sea. As a result of crust upheaval, in the middle of Tertiary Period, the Tethys Sea had become separated first from Pacific Ocean and later from the...     Още по темата

Main Black Sea Features The Black Sea is a part of the Roman Mediterranean and has the same origin. Its unique hydrological and hydrobiological characteristics make it very interesting and one of the most researched seas. The Black Sea is about four times bigger than Bulgaria and represents 1/853 share of the total area of all seas and ocean on the Earth. The biggest depth in the Black Sea is 2245 m, and the average -...     Още по темата

Крайбрежие Излаз на Черно море имат шест държави: България (354 km) Грузия (310 km) Румъния (225 km) Русия (800 km, включително Азовско море) Турция (1 329 km) Украйна (2 782 km, включително Азовско море) За четири от тях...     Още по темата

Chemical Balance Salt content In the oceanography salt content is what remains after the evaporation at 90° C of 1 kg sea water (filtrated and treated with chloric water in advance), dried at 380° C and hardened at 480° C. After this treatment the bromides turn into chlorides, bicarbonates and carbonates - in oxides, and the original substance burns. There is certain difference between the salt...     Още по темата