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| The Black Sea is the largest anoxic, or ]-free, marine system. This is a result of the great depth of the sea and the relatively low salinity (and therefore density) of the water flowing into it from rivers and the Mediterranean; freshwater and seawater mixing is limited to the uppermost 100-150m, with the water below this interface (called the ]) being exchanged only once every thousand years. There is therefore no significant gas exchange with the surface, and as a result ]ing ] matter in the ] consumes any available oxygen. In these anoxic conditions some ] microorganisms are able to use ] (SO<sub>4</sub><sup>2-</sup>) for oxidation of organic material, producing ] (HS) and ]. Large amounts of organic material reach the bottom of the sea and accumulate in the sediments in concentrations of up to 20%. These kinds of sediments are called ]. | The Black Sea is the largest anoxic, or ]-free, marine system. This is a result of the great depth of the sea and the relatively low salinity (and therefore density) of the water flowing into it from rivers and the Mediterranean; freshwater and seawater mixing is limited to the uppermost 100-150m, with the water below this interface (called the ]) being exchanged only once every thousand years. There is therefore no significant gas exchange with the surface, and as a result ]ing ] matter in the ] consumes any available oxygen. In these anoxic conditions some ] microorganisms are able to use ] (SO<sub>4</sub><sup>2-</sup>) for oxidation of organic material, producing ] (HS) and ]. Large amounts of organic material reach the bottom of the sea and accumulate in the sediments in concentrations of up to 20%. These kinds of sediments are called ]. | ||
| Countries bordering on the Black Sea are ], ], ], ], ] and ]. | Countries bordering on the Black Sea are ], ], ], ], ] and ]. | ||
| The most important cities along the coast are: ] (formerly ] and ]) -- ] -- ] -- ] -- ] | The most important cities along the coast are: ] (formerly ] and ]) -- ] -- ] -- ] -- ] | ||
Revision as of 06:54, 21 August 2002
The Black Sea is an inland sea between southeastern Europe and Asia Minor. It is connected to the Mediterranean Sea by the Bosporus and the Sea of Marmara. There is a net inflow of seawater through the Bosporus, 200km per year. There is an inflow of freshwater from the surrounding areas, especially central and middle-eastern Europe, totalling 320km per year. The most important river entering the Black Sea is the Danube.
The Black Sea region is thought to have been the original homeland of "Proto-Indo-European", the progenitor of the Indo-European language family, by some scholars. Others move the heartland further east towards the Caspian Sea.
In 1997, William Ryan and colleagues from Columbia University published evidence that a massive flood through the Bosporus occurred about 5600 BC. They wrote: "Ten cubic miles of water poured through each day, two hundred times what flows over Niagara Falls. ... The Bosporus flume roared and surged at full spate for at least three hundred days." The event flooded 60,000 square miles of land, and significantly expanded the Black Sea shoreline to the north and east. The Black Sea's water level raised many hundreds of feet, and it was transformed from a fresh-water landlocked lake into a salt water sea connected to the ocean. It has been popularly suggested that this event was the source of the legend for Noah's Flood. Forcing a match requires that considerable license be taken with the Biblical story, however.
The Black Sea is the largest anoxic, or oxygen-free, marine system. This is a result of the great depth of the sea and the relatively low salinity (and therefore density) of the water flowing into it from rivers and the Mediterranean; freshwater and seawater mixing is limited to the uppermost 100-150m, with the water below this interface (called the pycnocline) being exchanged only once every thousand years. There is therefore no significant gas exchange with the surface, and as a result decaying organic matter in the sediment consumes any available oxygen. In these anoxic conditions some extremeophile microorganisms are able to use sulphate (SO4) for oxidation of organic material, producing hydrogen sulphide (HS) and carbon dioxide. Large amounts of organic material reach the bottom of the sea and accumulate in the sediments in concentrations of up to 20%. These kinds of sediments are called sapropel.
Countries bordering on the Black Sea are Turkey, Bulgaria, Romania, Ukraine, Russia and Georgia.
The most important cities along the coast are: Istanbul (formerly Constantinople and Byzantium) -- Burgas -- Varna -- Odessa -- Sevastopol