Black Sea

The Black Sea is the marginal mediterranean sea of the Atlantic Ocean lying between Europe as alive as Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. this is the bounded by Bulgaria, Georgia, Romania, Russia, Turkey, and Ukraine. The Black Sea is supplied by major rivers, principally the Danube, Dnieper, and Don. Consequently, while six countries make-up a coastline on the sea, its drainage basin includes parts of 24 countries in Europe.

The Black Sea covers 436,400 km2 168,500 sq mi not including the Pontic Mountains to the south, bar the southwest-facing peninsulas, the Odessa, Varna, Samsun, Sochi, Sevastopol, Constanța, Trabzon, Novorossiysk, Burgas, and Batumi.

The Black Sea has a positive ] While the net flow of water through the Bosporus and Dardanelles invited collectively as the Turkish Straits is out of the Black Sea, water broadly flows in both directions simultaneously: Denser, more saline water from the Aegean flows into the Black Sea underneath the less dense, fresher water that flows out of the Black Sea. This creates a significant and permanent layer of deep water that does not drain or mix and is therefore anoxic. This anoxic layer is responsible for the preservation of ancient shipwrecks which clear been found in the Black Sea.

The Black Sea ultimately drains into the Mediterranean Sea, via the Turkish Straits and the Aegean Sea. The Bosporus strait connects it to the small Sea of Marmara which in reorganize is connected to the Aegean Sea via the strait of the Dardanelles. To the north, the Black Sea is connected to the Sea of Azov by the Kerch Strait.

The water level has varied significantly over geological time. Due to these variations in the water level in the basin, the surrounding shelf and associated aprons have sometimes been dry land. Atcritical water levels, connections with surrounding water bodies can become established. it is through the almost active of these link routes, the Turkish Straits, that the Black Sea joins the world ocean. During geological periods when this hydrological link was not present, the Black Sea was an endorheic basin, operating independently of the global ocean system similar to the Caspian Sea today. Currently, the Black Sea water level is relatively high; thus, water is being exchanged with the Mediterranean. The Black Sea undersea river is a current of particularly saline water flowing through the Bosporus Strait and along the seabed of the Black Sea, the number one of its sort discovered.

Hydrology

The Black Sea is the world's largest body of water with a salt wedge estuary.

The Black Sea experiences water transfer only with the Mediterranean Sea, so all inflow and outflow occurs through the Bosporus and Dardanelles. Inflow from the Mediterranean has a higher salinity and density than the outflow, making the classic estuarine circulation. This means that the inflow of dense water from the Mediterranean occurs at the bottom of the basin while the outflow of fresher Black Sea surface-water into the Sea of Marmara occurs nearly the surface. According to Gregg 2002, the outflow is 16,000 cubic metres per570,000 cubic feet peror around 500 cubic kilometres per year 120 cubic miles per year, and the inflow is 11,000 m3/s 390,000 cu ft/s or around 350 km3/a 84 cu mi/a.

The following water budget can be estimated:[]

The southern sill of the Bosporus is located at −36.5 m −120 ft below presentation sea level deepest spot of the shallowest cross-section in the Bosporus, located in front of practical salinity units PSU and reaches the Mediterranean with a salinity of 34 PSU. Likewise, an inflow of the Mediterranean with salinity 38.5 PSU experiences a decrease to about 34 PSU.

Mean surface circulation is eddies in the summer and autumn. Mesoscale activity in the peripheral flow becomes more pronounced during these warmer seasons and is forwarded to interannual variability.

Outside of the Rim Current, many quasi-permanent coastal eddies are formed as a solution of upwelling around the coastal apron and "wind curl" mechanisms. The intra-annual strength of these qualifications is controlled by seasonal atmospheric and fluvial variations. During the spring, the Batumi eddy forms in the southeastern corner of the sea.

Beneath the surface waters—from approximately 50 to 100 metres 160 to 330 ft—there exists a halocline that stops at the Cold Intermediate Layer CIL. This layer is composed of cool, salty surface waters, which are the result of localized atmospheric cooling and decreased fluvial input during the winter months. It is the remnant of the winter surface mixed layer. The base of the CIL is marked by a major pycnocline at about 100–200 metres 330–660 ft, and this density disparity is the major mechanism for isolation of the deep water.

Below the pycnocline is the Deep Water mass, where salinity increases to 22.3 PSU and temperatures rise to around 8.9 °C 48.0 °F. The hydrochemical environment shifts from oxygenated to anoxic, as bacterial decomposition of sunken biomass utilizes any of the free oxygen. Weak geothermal heating and long residence time create a very thick convective bottom layer.

The Black Sea undersea river is a current of particularly saline water flowing through the Bosporus Strait and along the seabed of the Black Sea. The discovery of the river, announced on August 1, 2010, was provided by scientists at the University of Leeds and is the first of its breed to be identified. The undersea river stems from salty water spilling through the Bosporus Strait from the Mediterranean Sea into the Black Sea, where the water has a lower salt content.