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Black Sea

2007 Schools Wikipedia Selection. Related subjects: General Geography

   Map of the Black Sea
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   Map of the Black Sea
   Satellite view of the Black Sea, taken by NASA MODIS
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   Satellite view of the Black Sea, taken by NASA MODIS

   The Black Sea is an inland sea between southeastern Europe and Anatolia
   that is actually a distant arm of the Atlantic Ocean by way of the
   Mediterranean Sea. It is connected to the Mediterranean by the Bosporus
   and the Sea of Marmara, and to the Sea of Azov by the Strait of Kerch.

   There is a net inflow of seawater through the Bosporus, 200 km³ per
   year. There is an inflow of freshwater from the surrounding areas,
   especially central and middle-eastern Europe, totalling 320 km³ per
   year. The most important river entering the Black Sea is the Danube.
   The Black Sea has an area of 422,000 km² and a maximum depth of 2210 m.

   Countries bordering on the Black Sea are Turkey, Bulgaria, Romania,
   Ukraine, Russia, and Georgia. The Crimean peninsula is a Ukrainian
   autonomous republic.

   Important cities along the coast include: Istanbul, Burgas, Varna,
   Constanţa, Yalta, Odessa, Sevastopol, Kerch, Novorossiysk, Sochi,
   Sukhumi, Poti, Batumi, Trabzon, Samsun and Zonguldak.

Name

   The Black Sea near Burgas in Bulgaria
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   The Black Sea near Burgas in Bulgaria

   Modern names of the Sea are universally translations of Black Sea,
   including Greek Μαύρη θάλασσα, Bulgarian Cherno more (Черно море),
   Georgian Shavi zghva (შავი ზღვა), Laz Ucha Zuğa, or simply Zuğa 'Sea',
   Romanian Marea Neagră, Russian Chyornoye More (Чёрное море), Turkish
   Karadeniz, Ukrainian Chorne More (Чорне море), Ubykh /ʃʷaʤa/. This name
   cannot be traced to an earlier date than the thirteenth century, but
   there are indications that it may be considerably older, cf. below.

   Strabo's Geography (1.2.10) reports that in antiquity the Black Sea was
   often just called "the Sea" (pontos), just like Homer was often simply
   called "the Poet". For the most part, Graeco-Roman tradition refers to
   the Black Sea as the 'Hospitable sea' Euxeinos Pontos (Εὔξεινος
   Πόντος). This is a euphemism replacing an earlier 'Inhospitable Sea'
   Pontos Axeinos, first attested in Pindar (early fifth century BCE).
   Strabo (7.3.6) thinks that the Black Sea was called inhospitable before
   Greek colonization because it was difficult to navigate, and because
   its shores were inhabited by savage tribes, and that the name was
   changed to hospitable after the Milesians had colonized, as it were
   making it part of the Greek civilization. It is, however, likely that
   the name Axeinos arose by popular etymology from an Iranian axšaina-
   'dark'; the designation Black Sea would, after all, go back to
   Antiquity. The motive for the name may be an ancient assignment of
   colors to the direction of the compass, black referring to the north,
   and red referring to the south. Herodotus on one occasion uses Red Sea
   and Southern Sea interchangeably. Cf. Schmitt 1996.

   Another possible explanation comes from the colour of the Black Sea's
   deep waters. Being further north than the Mediterranean Sea and much
   less saline, the microalgae concentration is much more rich, hence the
   dark colour. Visibility in the Black Sea is on average approximately
   five meters (5.5 yd), as compared to up to thirty-five meters (38 yd)
   in the Mediterranean. The water however is as blue as any other sea on
   bright, clear days.

   One Bulgarian understanding of the name is that the sea used to be
   quite stormy. Some sources stipulate that that goes back to the time of
   Noah's Ark. The Black Sea deluge theory is based on that idea.

Geology and bathymetry

   The Black Sea forms an enclosed basin, located between south-eastern
   Europe and Asia Minor. The basin was formed during the Miocene
   orogenies which uplifted the mountain ranges and divided the ancient
   Tethys Ocean into several brackish basins, including the Sarmatic Sea.
   The Caspian, Azov, Aral and Black Seas are the remnants of this
   evaporated basin.
   The Bulgarian coastline of the Black Sea has only a few small, barren
   islands.
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   The Bulgarian coastline of the Black Sea has only a few small, barren
   islands.

   The basin is divided into two sub-basins by a convexity extending south
   from the Crimean peninsula. The north-west of the basin is
   characterized by a relatively large shelf up to 190 km wide, which has
   a relatively shallow apron with gradients between 1:40 and 1:1000. The
   southern edge around Turkey and the eastern edge around Georgia
   however, are typified by a shelf that rarely exceeds 20km in width and
   an apron that is typically 1:40 gradient with numerous submarine
   canyons and channel extensions. The Euxine abyssal plain in the centre
   of the Black Sea reaches a maximum depth of 2,206m just south of Yalta
   on the Crimean peninsula. The basin is connected to the Mediterranean
   Sea via the Turkish Straits System (TSS) in the south-west, which
   includes the Bosporus and Dardanelles straits and the Sea of Marmara.
   The Black Sea is connected to the Sea of Azov in the north-east via the
   Kerch straits.

Hydrology and hydrochemistry

   The Black Sea is the world’s largest meromictic basin, with 90% of its
   volume occupied by anoxic waters. The current hydrochemical
   configuration is primarily controlled by basin topography and fluvial
   inputs, which result in a strongly stratified vertical structure and a
   positive water balance. The upper layers are generally cooler, less
   dense and less salty than the deeper waters, as they are fed by large
   fluvial systems, whereas the deep waters originate from the warm, salty
   waters of the Mediterranean. This influx of dense water from
   Mediterranean is balanced by an outflow of fresher Black Sea
   surface-water into the Marmara Sea, maintaining the stratification and
   salinity levels.
   Bay of Sudak
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   Bay of Sudak

   The surface water has an average salinity of 18-18.5 ppt and contains
   oxygen and other nutrients required to sustain biotic activity. These
   waters circulate in a basin-wide anti-cyclonic shelfbreak gyre known as
   the Rim Current which transports water round the perimeter of the Black
   Sea. Within this feature, two smaller cyclonic gyres operate, occupying
   the eastern and western sectors of the basin. Outside the Rim Current,
   numerous quasi-permanent coastal eddies are formed due to upwelling
   around the coastal apron and ‘wind curl’ mechanisms. The intra-annual
   strength of these features is controlled by seasonal atmospheric and
   fluvial variations. Sea Surface Temperature of the surface waters
   varies seasonally from 8°C to 30°C.

   Directly beneath the surface waters the Cold Intermediate Layer (CIL)
   is found. This layer is composed of cool, salty surface waters, which
   are the result of localised atmospheric cooling and decreased fluvial
   input during the winter months. The production of this water is
   focussed in the centre of the major gyres and on the NW shelf and as
   the water is not dense enough to penetrate the deep waters, isopycnal
   advection occurs, dispersing the water across the entire basin. The
   base of the CIL is marked by a major thermocline, halocline and
   pycnocline at ~100-200m and this density disparity is the major cause
   of deep-water isolation.

   Below the pycnocline, salinity increases to 22-22.5 ppt and
   temperatures rise to ~8.5°C. The hydrochemical environment shifts from
   oxygenated to anoxic, as bacterial decomposition of sunken biomass
   utilises all of the free oxygen. Certain species of extremophile
   bacteria are capable of using sulfate (SO[4]^2−) in the oxidation of
   organic material, which leads to the creation of hydrogen sulphide
   (H[2]S). This reacts with seawater to produce sulfuric acid
   (H[2]SO[4]). This enables the precipitation of sulfides such as
   iron-sulphides like pyrite, greigite and iron-monosulphide as well as
   the dissolution of carbonate matter such as Calcium carbonate (CaCO[3])
   found in shells. Organic matter, including anthropogenic artefacts such
   as boat hulls, are well preserved. During periods of high surface
   productivity, short-lived algal blooms cause organic rich layer known
   as sapropels to occur. Another danger to people posed by the anoxic
   layer could come from a small asteroid's impact into the Black Sea.
   Recently modelling shows there is a significant threat to life for
   people living on the sea's shore. SEE: R.D. Schuiling, R.B. Cathcart,
   V. Badescu, D. Isvoranu and E. Pelinovsky, "Asteroid impact in the
   Black Sea. Death by drowning or asphyxiation?", Natural Hazards
   (October 2006) DOI: 10.1007/s11069-006-0017-7.

Mediterranean connection during the Holocene

   While it is agreed that the Black Sea has been a freshwater lake (at
   least in upper layers) with a considerably lower level during the last
   glaciation, its postglacial development into a marine sea is still a
   subject of intensive study and debate. There are catastrophic scenarios
   such as put forward by William Ryan and Walter Pitman as well as models
   emphasizing a more gradual transition to saline conditions and
   transgression in the Black Sea.

   They are based on different theories about the level the freshwater
   lake had reached by the time the Mediterranean Sea was high enough to
   flow over the Dardanelles and the Bosporus. On the other hand, a study
   of the sea floor on the Aegean side shows that in the 8th millennium BC
   there was a large flow of fresh water out of the Black Sea ( New
   Scientist, 4 May 2002, p. 13).

   In a series of expeditions, a team of marine archeologists led by
   Robert Ballard identified what appeared to be ancient shorelines,
   freshwater snail shells, drowned river valleys, tool-worked timbers,
   and man-made structures in roughly 300 feet (100 m) of water off the
   Black Sea coast of modern Turkey. Radiocarbon dating of freshwater
   mollusk remains indicated an age of about 7,000 years.

Deluge theory

   In 1997, William Ryan and Walter Pitman from Columbia University
   published a theory that a massive flood through the Bosporus occurred
   in ancient times. They claim that the Black and Caspian Seas were vast
   freshwater lakes, but that about 5600 BC, the Mediterranean spilled
   over a rocky sill at the Bosporus, creating the current communication
   between the Black and Mediterranean Seas. Subsequent work has been done
   both to support and to discredit this theory, and archaeologists still
   debate it. This has led some to associate this catastrophe with
   prehistoric flood myths.

History

   The steppes to the north of the Black Sea have been suggested as the
   original homeland ( Urheimat) of the speakers of the
   Proto-Indo-European language, (PIE) the progenitor of the Indo-European
   language family, by some scholars (see Kurgan; others move the
   heartland further east towards the Caspian Sea, yet others to
   Anatolia).

   The land at the eastern end of the Black Sea, Colchis (now Georgia),
   marked for the Greeks an edge of the known world.

Holiday resorts and spas

   Photo of the Black Sea near Sochi, taken in 1915
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   Photo of the Black Sea near Sochi, taken in 1915
     * Ahtopol (Bulgaria)
     * Anapa (Russia)
     * Albena (Bulgaria)
     * Alupka (Crimea)
     * Alushta (Crimea)
     * Balchik (Bulgaria)
     * Batumi (Georgia)
     * Chakvi (Georgia)
     * Costineşti (Romania)
     * Emona (Bulgaria)
     * Eupatoria (Crimea)
     * Theodosia (Crimea)
     * Giresun (Turkey)
     * Gagra (Abkhazia, Georgia^1)
     * Golden Sands (Bulgaria)
     * Gonio (Georgia)
     * Gurzuf (Crimea)
     * Jupiter (Romania)
     * Kiten (Bulgaria)
     * Kobuleti (Georgia)
     * Koktebel (Crimea)
     * Kvariati (Georgia)
     * Mamaia (Romania)
     * Mangalia (Romania)
     * Neptun (Romania)

                                    * Nesebar (Bulgaria)
                                    * Novorossiysk (Russia)
                                    * Obzor (Bulgaria)
                                    * Odessa (Ukraine)
                                    * Olimp (Romania)
                                    * Pitsunda (Abkhazia, Georgia^1)
                                    * Pomorie (Bulgaria)
                                    * Primorsko (Bulgaria)
                                    * Rize (Turkey)
                                    * Rusalka (Bulgaria)
                                    * Samsun(Turkey)
                                    * Saturn (Romania)
                                    * Sinop(Turkey)
                                    * Sochi (Russia)
                                    * Sozopol (Bulgaria)
                                    * Sudak (Crimea)
                                    * Sunny Beach (Bulgaria)
                                    * Şile (Turkey)
                                    * Sveti Vlas (Bulgaria)
                                    * Trabzon (Turkey)
                                    * Tuapse (Russia)
                                    * Ureki (Georgia)
                                    * Vama Veche (Romania)
                                    * Venus (Romania)
                                    * Yalta (Crimea)

   ^1 Abkhazia has been a de facto independent republic since 1992,
   although remains a de jure autonomous republic of Georgia.

Regional organizations

   Black Sea Economic Cooperation (BSEC) ██ members ██ observers
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   Black Sea Economic Cooperation (BSEC) ██ members ██ observers
   GUAM Organization for Democracy and Economic Development
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   GUAM Organization for Democracy and Economic Development
   Community of Democratic Choice (CDC) ██ members ██ observers
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   Community of Democratic Choice (CDC) ██ members ██ observers
   Black Sea Forum for Partnership and Dialogue (BSF) ██ members
   ██ observers
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   Black Sea Forum for Partnership and Dialogue (BSF) ██ members
   ██ observers

   See also the Balkans Regional organizations and Post-Soviet Regional
   organizations

   Retrieved from " http://en.wikipedia.org/wiki/Black_Sea"
   This reference article is mainly selected from the English Wikipedia
   with only minor checks and changes (see www.wikipedia.org for details
   of authors and sources) and is available under the GNU Free
   Documentation License. See also our Disclaimer.
