The Black Sea undersea river is a current of particularly

saline water Saline water (more commonly known as salt water) is water that contains a high concentration of dissolved salts (mainly sodium chloride). On the United States Geological Survey (USGS) salinity scale, saline water is saltier than brackish wat ...

flowing through the

Bosphorus Strait The Bosporus or Bosphorus Strait ( ; , colloquially ) is a natural strait and an internationally significant waterway located in Istanbul, Turkey. The Bosporus connects the Black Sea to the Sea of Marmara and forms one of the continental b ...

and along the

seabed The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as seabeds. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

of the

Black Sea The Black Sea is a marginal sea, marginal Mediterranean sea (oceanography), mediterranean sea lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bound ...

. The discovery of the river, announced on 1 August 2010, was made by scientists at the

University of Leeds The University of Leeds is a public research university in Leeds, West Yorkshire, England. It was established in 1874 as the Yorkshire College of Science. In 1884, it merged with the Leeds School of Medicine (established 1831) and was renamed Y ...

, and is the first of its kind in the world. The undersea river stems from salty water spilling through the Bosphorus Strait from the

Mediterranean Sea The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...

into the Black Sea, where the water has a lower salt content. The river system formed roughly 7,500 years ago when the Bosphorus developed its two-way depth-separated flow. Scientists have previously discovered channels running along ocean floors, based on

sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances ( ranging), communicate with or detect objects o ...

scanning. One of the largest of these runs from the mouth of the Amazon River into the

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

. Though it was suspected that these channels might function as rivers, it was only with the discovery of the Black Sea river that this suspicion was confirmed. Because of the power and unpredictability of these streams, they have been difficult to explore directly. A team of scientists headed by Jeff Peakall and Daniel Parsons of the University of Leeds collaborated with scientists from the

University of Southampton The University of Southampton (abbreviated as ''Soton'' in post-nominal letters) is a public university, public research university in Southampton, England. Southampton is a founding member of the Russell Group of research-intensive universit ...

Memorial University of Newfoundland Memorial University of Newfoundland, or MUN (), is a Public university, public research university in the province of Newfoundland and Labrador, based in St. John's, Newfoundland and Labrador, St. John's, with satellite campuses in Corner Brook ...

, and the Turkish Institute of Marine Sciences. The team used the

Natural Environment Research Council The Natural Environment Research Council (NERC) is a British Research Councils UK, research council that supports research, training and knowledge transfer activities in the environmental sciences. History NERC began in 1965 when several envir ...

's Autosub3 – a 7-metre torpedo-shaped

autonomous underwater vehicle An autonomous underwater vehicle (AUV) is a robot that travels underwater without requiring continuous input from an operator. AUVs constitute part of a larger group of undersea systems known as unmanned underwater vehicles, a classification tha ...

– to get as close to the current as possible. The river was found to be long, up to deep and wide. Though smaller than the Amazon channel, the undersea river still carried ten times more water than the

Rhine The Rhine ( ) is one of the List of rivers of Europe, major rivers in Europe. The river begins in the Swiss canton of Graubünden in the southeastern Swiss Alps. It forms part of the Swiss-Liechtenstein border, then part of the Austria–Swit ...

. It flows at a speed of , with passing through per second. Were it a surface river, it would rank as the sixth largest river in the world. The river was found to contain features typical of surface rivers, such as

river bank In geography, a bank is the land alongside a body of water. Different structures are referred to as ''banks'' in different fields of geography. In limnology (the study of inland waters), a stream bank or river bank is the terrain alongsid ...

floodplain A floodplain or flood plain or bottomlands is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high Discharge (hydrolog ...

waterfall A waterfall is any point in a river or stream where water flows over a vertical drop or a series of steep drops. Waterfalls also occur where meltwater drops over the edge of a tabular iceberg or ice shelf. Waterfalls can be formed in seve ...

s and

rapids Rapids are sections of a river where the river bed has a relatively steep stream gradient, gradient, causing an increase in water velocity and turbulence. Flow, gradient, constriction, and obstacles are four factors that are needed for a rapid t ...

. One major difference is that the underwater river, when rounding a bend, moves in currents spinning in the opposite direction from those on land. The river works as a

density current Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek language, Greek letter rho), although the Latin letter ''D'' (or ''d'') ...

, because it carries

sediment Sediment is a solid material that is transported to a new location where it is deposited. It occurs naturally and, through the processes of weathering and erosion, is broken down and subsequently sediment transport, transported by the action of ...

s along the sea floor and has a higher

salinity Salinity () is the saltiness or amount of salt (chemistry), salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensio ...

than the surrounding water. A secondary channel exists ~6 km east of the main channel complex. It was formed from intermittent leakage, and has eroded through several shore-parallel ridges.

References

{{reflist Black Sea Physical oceanography Coastal and oceanic landforms Bosphorus

See also

References