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Lake Van
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Lake Van ( ) is the largest lake in Turkey, located in the far east of the country. It is a saline and soda lake, receiving water from numerous small streams that descend from the surrounding mountains. Lake Van is one of the world's largest endorheic lakes (having no outlet). The original outlet from the basin was blocked by an ancient volcanic eruption.
Van is across at its widest point, averaging a depth of with a maximum recorded depth of .
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Encyclopedia
Lake Van ( ) is the largest lake in Turkey, located in the far east of the country. It is a saline and soda lake, receiving water from numerous small streams that descend from the surrounding mountains. Lake Van is one of the world's largest endorheic lakes (having no outlet). The original outlet from the basin was blocked by an ancient volcanic eruption.
Hydrology and chemistry
Lake Van is across at its widest point, averaging a depth of with a maximum recorded depth of . The lake surface lies above sea level and the shore length is . Lake Van has an area of and a volume of .
The western portion of the lake is deepest, with a large basin deeper than lying northeast of Tatvan and south of Ahlat. The eastern arms of the lake are shallower. The Van-Ahtamar portion shelves gradually, with a maximum depth of about on its northwest side where it joins the rest of the lake. The Ercis arm is much shallower, mostly less than , with a maximum depth of about .
The lake water is strongly alkaline (pH 9.7–9.8) and rich in sodium carbonate and other salts, which are extracted by evaporation and used as detergents.
Geology
The lake's outlet was blocked at some time during the Pleistocene, when lava flows from Nemrut volcano blocked westward outflow towards the Mus Plain. Now dormant, Nemrut Dagi is close to the western shore of the lake, and another dormant stratovolcano, Süphan Dagi dominates the northern side of the lake.
The water level of the lake has often altered dramatically: near Tatvan, Oswald (see Geology of Armenia, 1901) noted a raised beach high above the present level of the lake as well as recently drowned trees. Investigation by Degens and others in the early 1980s determined that the highest lake levels ( above the current height) had been during the last ice age, about 18,000 years ago. About 9,500 years ago there was a dramatic drop to more than below the present level. This was followed by an equally dramatic rise around 6,500 years ago.
Similar but smaller fluctuations have been seen recently. The level of the lake rose by at least three metres during the 1990s, drowning much agricultural land, and (after a brief period of stability and then retreat) seems to be rising again. The level has risen about two meters in the ten years immediatey prior to 2004.
As a deep lake with no outlet, Lake Van has accumulated great amounts of sediment washed in from surrounding plains and valleys, and occasionally deposited as ash from eruptions of nearby volcanoes.
This layer of sediment is estimated to be up to thick in places, and has attracted climatologists and vulcanologists interested in drilling cores to examine the layered sediments.
In 1989 and 1990, an international team of geologists led by Dr. Stephan Kempe from the University of Hamburg (now Professor at the Technische Universität Darmstadt) retrieved ten sediment cores from depths up to . Although these cores only penetrated the first few meters of sediment, they provided sufficient varves to give climate data for up to 14,570 years BP.
A team of scientists headed by palaeontologist Professor Thomas Litt at the University of Bonn has applied for funding from the International Continental Scientific Drilling Program (ICDP) for a new, deeper drilling project to examine the lake's sediments. Litt expects to find that "Lake Van stores the climate history of the last 800,000 years—an incomparable treasure house of data which we want to tap for at least the last 500,000 years." A test drilling in 2004 detected evidence of 15 volcanic eruptions in the past 20,000 years.
Ecology
The only fish known to live in the brackish water of Lake Van is Chalcalburnus tarichi the Pearl Mullet or inci kefali, a Cyprinid fish related to chub and dace, which is caught during the spring floods. In May and June, these fish migrate from the lake to less alkaline water, spawning either near the mouths of the rivers feeding the lake or in the rivers themselves. After spawning season it returns to the lake.
103 species of phytoplankton have been recorded in the lake including Diatome, Bacteriophyta, Cyanophyta, Chlorophyta, Flagellata and Phaeophyta. 36 species of zooplankton have also been recorded including Rotatoria, Cladocera and Copepoda in the lake.
In 1991, researchers reported the discovery of tall microbialites in Lake Van. These are solid towers on the lake bed created by mats of coccoid cyanobacteria (Pleurocapsa group) that create aragonite in combination with calcite precipitating out of the lake water.
The Lake Van region is the home of the rare Van Kedisi breed of cat, noted for among other things its unusual fascination with water.
Since about 1995 there have been reported sightings of a 'Lake Van monster' about in length named Van Canavari ("Monster of Van").
The lake is surrounded by fruit and grain-growing agricultural areas.
History
Tushpa, the capital of Urartu, was located near the shores of Lake Van, on the site of what became medieval Van's castle, west of present-day Van city. The ruins of the medieval city of Van are still visible below the southern slopes of the rock on which Van Castle is located.
Armenian kingdoms
The lake was the centre of the Armenian kingdom of Ararat from about 1000 BC, afterwards of the Satrapy of Armina, Kingdom of Greater Armenia, and the Armenian Kingdom of Vaspurakan.
Along with Lake Sevan in today's Armenia and Lake Urmia in today's Iran, Van was one of the three great lakes of the Armenian Kingdom, referred to as the seas of Armenia (in ancient Assyrian sources: "tâmtu ša mât Nairi" (Upper Sea of Nairi), the Lower Sea being Lake Urmia). Over time, the lake was known by various Armenian names, including .
Byzantine empire
By the 11th century the region around Lake Van was on the border between the Byzantine empire, with its capital at Constantinople, and the Seljuk Turkish empire, with its capital at Isfahan. In the uneasy peace between the two empires, local Armenian-Byzantine landowners employed Turcoman gazis and Byzantine akritoi for protection. However, these mercenaries often turned to looting for their own benefit.
In the second half of the 11th century the situation on the southeast border of the Byzantine empire had reached such a point that Emperor Romanus IV Diogenes launched a campaign to re-conquer Armenia and head off growing Seljuk control. Diogenes and his large army crossed the Euphrates and confronted a much smaller Seljuk force led by Alp Arslan at the Battle of Manzikert, north of Lake Van on 26 August 1071. Despite their greater numbers, the cumbersome Byzantine force was defeated by the more mobile Turkish horsemen and Diogenes was captured.
Seljuk empire
Alp Arslan divided the conquered eastern portions of the Byzantine empire among his Turcoman generals, with each ruled as a hereditary beylik, under overall sovereignty of the Great Seljuq Empire. Alp Arslan gave the region around Lake Van to his commander Sökmen el Kutbî (literally Sökmen the Slave), who set up his capital at Ahlat on the western side of the lake. The dynasty of Ahlatshahs (also known as Sökmenler) ruled this area from 1085 to 1192.
The Ahlatshahs were succeeded by the Ayyubid dynasty.
Architecture
Near the Van Castle and the southern shore, on Akdamar Island lies the Church of the Holy Cross (Armenian: ????? ???, Surb Khach), which served as a royal church to the Armenian Vaspurakan kingdom.
The Ahlatshahs left a large number of historic tombstones in and around the town of Ahlat. Local administrators are currently trying to have the tombstones included in UNESCO's World Heritage List, where they are currently listed tentatively.
Transportation
The railway connecting Turkey and Iran built in the 1970s uses a train ferry across Lake Van between the cities Tatvan and Van, rather than building railway tracks around the rugged shore line. Transfer from train to ship and back again limits the total carrying capacity.
In May, 2008 talks started between Iran and Turkey to upgrade the ferry to a double track electrified railway.
Islands
See also
External links
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