Caspian Sea

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Caspian Sea
Caspian Sea from orbit.jpg
The Caspian Sea as taken by the MODIS on the orbiting Terra satellite, June 2003
Coordinates 41°40′N50°40′E / 41.667°N 50.667°E / 41.667; 50.667 Coordinates: 41°40′N50°40′E / 41.667°N 50.667°E / 41.667; 50.667
Type Endorheic, Saline, Permanent, Natural
Primary inflows Volga River, Ural River, Kura River, Terek River
Primary outflows Evaporation, Kara-Bogaz-Gol
Catchment area 3,626,000 km2 (1,400,000 sq mi) [1]
Basin  countries Azerbaijan, Iran, Kazakhstan, Russia, Turkmenistan
Max. length1,030 km (640 mi)
Max. width435 km (270 mi)
Surface area371,000 km2 (143,200 sq mi)
Average depth211 m (690 ft)
Max. depth1,025 m (3,360 ft)
Water volume78,200 km3 (18,800 cu mi)
Residence time 250 years
Shore length17,000 km (4,300 mi)
Surface elevation−28 m (−92 ft)
Islands 26+
Settlements Baku (Azerbaijan), Rasht (Iran), Aktaw (Kazakstan), Makhachkala (Russia), Türkmenbaşy (Turkmenistan) (see article )
References [1]
1 Shore length is not a well-defined measure.

The Caspian Sea is the world's largest inland body of water, variously classed as the world's largest lake or a full-fledged sea. It is an endorheic basin (a basin without outflows) located between Europe and Asia, to the east of the Caucasus Mountains and to the west of the broad steppe of Central Asia. It is bounded by Kazakhstan to the northeast, Russia to the northwest, Azerbaijan to the west, Iran to the south, and Turkmenistan to the southeast. The Caspian Sea is home to a wide range of species and may be best known for its caviar and oil industries. Pollution from the oil industry and dams on rivers draining into the Caspian Sea have had negative effects on the organisms living in the sea.

Body of water Any significant accumulation of water, generally on a planets surface

A body of water or waterbody is any significant accumulation of water, generally on a planet's surface. The term most often refers to oceans, seas, and lakes, but it includes smaller pools of water such as ponds, wetlands, or more rarely, puddles. A body of water does not have to be still or contained; rivers, streams, canals, and other geographical features where water moves from one place to another are also considered bodies of water.

Sea Large body of salt water

The sea, the world ocean or simply the ocean is the connected body of salty water that covers over 70 percent of the Earth's surface. It moderates the Earth's climate and has important roles in the water cycle, carbon cycle, and nitrogen cycle. It has been travelled and explored since ancient times, while the scientific study of the sea—oceanography—dates broadly from the voyages of Captain James Cook to explore the Pacific Ocean between 1768 and 1779. The word "sea" is also used to denote smaller, partly landlocked sections of the ocean.

Endorheic basin Closed drainage basin that allows no outflow

An endorheic basin is a limited drainage basin that normally retains water and allows no outflow to other external bodies of water, such as rivers or oceans, but converges instead into lakes or swamps, permanent or seasonal, that equilibrate through evaporation. Such a basin may also be referred to as a closed or terminal basin or as an internal drainage system or interior drainage basin.


The wide and endorheic Caspian Sea has a north–south orientation and its main freshwater inflow, the Volga River, enters at the shallow north end. Two deep basins occupy its central and southern areas. These lead to horizontal differences in temperature, salinity, and ecology. The Caspian Sea spreads out over nearly 750 miles (1,200 km) from north to south, with an average width of 200 miles (320 km). It covers a region of around 149,200 square miles (386,400 square km)—bigger than the region of Japan—and its surface is about 90 feet (27 meters) below sea level. The sea bed in the southern part reaches as low as 1,023 m (3,356 ft) below sea level, which is the second lowest natural depression on earth after Lake Baikal (−1,180 m, −3,871 ft). The ancient inhabitants of its coast perceived the Caspian Sea as an ocean, probably because of its saltiness and large size.

Japan Constitutional monarchy in East Asia

Japan is an island country in East Asia. Located in the Pacific Ocean, it lies off the eastern coast of the Asian continent and stretches from the Sea of Okhotsk in the north to the East China Sea and the Philippine Sea in the south.

Sea level Average level for the surface of the ocean at any given geographical position on the planetary surface

Mean sea level (MSL) is an average level of the surface of one or more of Earth's oceans from which heights such as elevation may be measured. MSL is a type of vertical datum – a standardised geodetic datum – that is used, for example, as a chart datum in cartography and marine navigation, or, in aviation, as the standard sea level at which atmospheric pressure is measured to calibrate altitude and, consequently, aircraft flight levels. A common and relatively straightforward mean sea-level standard is the midpoint between a mean low and mean high tide at a particular location.

Depression (geology) landform sunken or depressed below the surrounding area

A depression in geology is a landform sunken or depressed below the surrounding area. Depressions form by various mechanisms.

The sea has a surface area of 371,000 km2 (143,200 sq mi) (not including the detached lagoon of Garabogazköl) and a volume of 78,200 km3(18,800 cu mi). It has a salinity of approximately 1.2% (12 g/l), about a third of the salinity of most seawater.

Garabogazköl bay in Turkmenistan

The Garabogazköl Aylagy or Kara-Bogaz-Gol is a shallow inundated depression in the northwestern corner of Turkmenistan. It forms a lagoon of the Caspian Sea with a surface area of about 18,000 km2 (6,900 sq mi). It is separated from the Caspian Sea proper, which lies immediately to the west, by a narrow, rocky ridge having a very narrow opening in the rock through which the Caspian waters flow, cascading down into Garabogazköl, leading to the Turkmen language name of the bay, "Mighty Strait Lake". The water volume of the bay fluctuates seasonally with the Caspian Sea; at times it becomes a large bay of the Caspian Sea, while at other times its water level drops drastically.

Salinity The proportion of salt dissolved in a body of water

Salinity is the saltiness or amount of salt dissolved in a body of water, called saline water. This is usually measured in . Salinity is an important factor in determining many aspects of the chemistry of natural waters and of biological processes within it, and is a thermodynamic state variable that, along with temperature and pressure, governs physical characteristics like the density and heat capacity of the water.

Seawater Water from a sea or ocean

Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5%. This means that every kilogram of seawater has approximately 35 grams (1.2 oz) of dissolved salts. Average density at the surface is 1.025 kg/L. Seawater is denser than both fresh water and pure water because the dissolved salts increase the mass by a larger proportion than the volume. The freezing point of seawater decreases as salt concentration increases. At typical salinity, it freezes at about −2 °C (28 °F). The coldest seawater ever recorded was in 2010, in a stream under an Antarctic glacier, and measured −2.6 °C (27.3 °F). Seawater pH is typically limited to a range between 7.5 and 8.4. However, there is no universally accepted reference pH-scale for seawater and the difference between measurements based on different reference scales may be up to 0.14 units.


The word Caspian is derived from the name of the Caspi, an ancient people who lived to the southwest of the sea in Transcaucasia. [2] Strabo wrote that "to the country of the Albanians belongs also the territory called Caspiane, which was named after the Caspian tribe, as was also the sea; but the tribe has now disappeared". [3] Moreover, the Caspian Gates, which is the name of a region in Iran's Tehran province, possibly indicates that they migrated to the south of the sea. The Iranian city of Qazvin shares the root of its name with that of the sea. In fact, the traditional Arabic name for the sea itself is Baḥr al-Qazwin (Sea of Qazvin). [4]


The Caspians were a people of antiquity who dwelled along the southern and southwestern shores of the Caspian Sea, in the region known as Caspiane. Caspian is the English version of the Greek ethnonym Kaspioi, mentioned twice by Herodotus among the Achaemenid satrapies of Darius and applied by Strabo. The name is not attested in Old Iranian.

Transcaucasia geopolitical region located on the border of Eastern Europe and Western Asia

Transcaucasia, or the South Caucasus, is a geographical region in the vicinity of the southern Caucasus Mountains on the border of Eastern Europe and Western Asia. Transcaucasia roughly corresponds to modern Georgia, Armenia, and Azerbaijan. Total area of these countries is about 186,100 square kilometres. Transcaucasia and Ciscaucasia together comprise the larger Caucasus geographical region that divides Eurasia.

Strabo Greek geographer, philosopher and historian

Strabo was a Greek geographer, philosopher, and historian who lived in Asia Minor during the transitional period of the Roman Republic into the Roman Empire.

In classical antiquity among Greeks and Persians it was called the Hyrcanian Ocean. [5] In Persian middle age, as well as in modern Iran, it is known as درياى خزر, Daryā-e Khazar; it is also sometimes referred to as Mazandaran Sea (Persian : دریای مازندران) in Iran. [6] Ancient Arabic sources refer to it as Baḥr Gīlān (بحر گیلان) meaning "the Gilan Sea".

Classical antiquity Age of the ancient Greeks and the Romans

Classical antiquity is the period of cultural history between the 8th century BC and the 5th or 6th century AD centered on the Mediterranean Sea, comprising the interlocking civilizations of ancient Greece and ancient Rome known as the Greco-Roman world. It is the period in which Greek and Roman society flourished and wielded great influence throughout Europe, North Africa and Western Asia.

Hyrcania is a historical region composed of the land south-east of the Caspian Sea in modern-day Iran, bound in the south by the Alborz mountain range and the Kopet Dag in the east.

Iran Country in Western Asia

Iran, also called Persia and officially known as the Islamic Republic of Iran, is a country in Western Asia. With over 81 million inhabitants, Iran is the world's 18th most populous country. Comprising a land area of 1,648,195 km2 (636,372 sq mi), it is the second largest country in the Middle East and the 17th largest in the world. Iran is bordered to the northwest by Armenia and Azerbaijan, to the north by the Caspian Sea, to the northeast by Turkmenistan, to the east by Afghanistan and Pakistan, to the south by the Persian Gulf and the Gulf of Oman, and to the west by Turkey and Iraq. The country's central location in Eurasia and Western Asia, and its proximity to the Strait of Hormuz, give it geostrategic importance. Tehran is the country's capital and largest city, as well as its leading economic and cultural center.

Turkic languages refer to the lake as Khazar Sea. In Turkmen, the name is Hazar deňizi, in Azeri, it is Xəzər dənizi, and in modern Turkish, it is Hazar denizi. In all these cases, the second word simply means "sea", and the first word refers to the historical Khazars who had a large empire based to the north of the Caspian Sea between the 7th and 10th centuries. An exception is Kazakh, where it is called Каспий теңізі, Kaspiy teñizi (Caspian Sea).

Turkic languages Language family

The Turkic languages are a language family of at least thirty-five documented languages, spoken by the Turkic peoples of Eurasia from Eastern Europe, the Caucasus, Central Asia, and West Asia all the way to North Asia and East Asia. The Turkic languages originated in a region of East Asia spanning Western China to Mongolia, where Proto-Turkic is thought to have been spoken, according to one estimate, around 2,500 years ago, from where they expanded to Central Asia and farther west during the first millennium.

Turkmen is the official language of Turkmenistan and the language of the Turkmen peoples of Central Asia. It is a Turkic language spoken by 3.5 million people in Turkmenistan as well as by around 719,000 people in northeastern Iran and 1.5 million people in northwestern Afghanistan. Not all "Turkmen" in northeastern Iran are speakers of Turkmen; many are speakers of Khorasani Turkic.

Turkish language Turkic language (possibly Altaic)

Turkish, also referred to as Istanbul Turkish, is the most widely spoken of the Turkic languages, with around 10–15 million native speakers in Southeast Europe and 60–65 million native speakers in Western Asia. Outside Turkey, significant smaller groups of speakers exist in Germany, Bulgaria, North Macedonia, Northern Cyprus, Greece, the Caucasus, and other parts of Europe and Central Asia. Cyprus has requested that the European Union add Turkish as an official EU language, even though Turkey is not a member state.

Renaissance European maps labelled it as Abbacuch Sea (Oronce Fine's 1531 world map), Mar de Bachu (Ortellius' 1570 map), or Mar de Sala (Mercator's 1569 map).

Old Russian sources call it the Khvalyn or Khvalis Sea (Хвалынское море / Хвалисское море) after the name of Khwarezmia. [7] In modern Russian, it is called Каспи́йское мо́ре, Kaspiyskoye more.

Physical characteristics


The Caspian Sea, like the Black Sea, Namak Lake, and Lake Urmia, is a remnant of the ancient Paratethys Sea. It became landlocked about 5.5 million years ago due to tectonic uplift and a fall in sea level. During warm and dry climatic periods, the landlocked sea almost dried up, depositing evaporitic sediments like halite that were covered by wind-blown deposits and were sealed off as an evaporite sink when cool, wet climates refilled the basin. (Comparable evaporite beds underlie the Mediterranean.) Due to the current inflow of fresh water, the Caspian Sea is a freshwater lake in its northern portions, and is most saline on the Iranian shore, where the catchment basin contributes little flow. [8] Currently, the mean salinity of the Caspian is one third that of Earth's oceans. The Garabogazköl embayment, which dried up when water flow from the main body of the Caspian was blocked in the 1980s but has since been restored, routinely exceeds oceanic salinity by a factor of 10. [9]


Area around the Caspian Sea. Yellow area indicates the (approximate) drainage area. CaspianSeaDrainage v1.png
Area around the Caspian Sea. Yellow area indicates the (approximate) drainage area.

The Caspian Sea is the largest inland body of water in the world and accounts for 40 to 44% of the total lacustrine waters of the world. [10] The coastlines of the Caspian are shared by Azerbaijan, Iran, Kazakhstan, Russia, and Turkmenistan. The Caspian is divided into three distinct physical regions: the Northern, Middle, and Southern Caspian. [11] The Northern–Middle boundary is the Mangyshlak Threshold, which runs through Chechen Island and Cape Tiub-Karagan. The Middle–Southern boundary is the Apsheron Threshold, a sill of tectonic origin between the Eurasian continent and an oceanic remnant, [12] that runs through Zhiloi Island and Cape Kuuli. [13] The Garabogazköl Bay is the saline eastern inlet of the Caspian, which is part of Turkmenistan and at times has been a lake in its own right due to the isthmus that cuts it off from the Caspian.

Differences between the three regions are dramatic. The Northern Caspian only includes the Caspian shelf, [14] and is very shallow; it accounts for less than 1% of the total water volume with an average depth of only 5–6 metres (16–20 ft). The sea noticeably drops off towards the Middle Caspian, where the average depth is 190 metres (620 ft). [13] The Southern Caspian is the deepest, with oceanic depths of over 1,000 metres (3,300 ft), greatly exceeding the depth of other regional seas, such as the Persian Gulf. The Middle and Southern Caspian account for 33% and 66% of the total water volume, respectively. [11] The northern portion of the Caspian Sea typically freezes in the winter, and in the coldest winters ice forms in the south as well. [15]

Over 130 rivers provide inflow to the Caspian, with the Volga River being the largest. A second affluent, the Ural River, flows in from the north, and the Kura River flows into the sea from the west. In the past, the Amu Darya (Oxus) of Central Asia in the east often changed course to empty into the Caspian through a now-desiccated riverbed called the Uzboy River, as did the Syr Darya farther north. The Caspian also has several small islands; they are primarily located in the north and have a collective land area of roughly 2,000 km2 (770 sq mi). Adjacent to the North Caspian is the Caspian Depression, a low-lying region 27 metres (89 ft) below sea level. The Central Asian steppes stretch across the northeast coast, while the Caucasus mountains hug the western shore. The biomes to both the north and east are characterized by cold, continental deserts. Conversely, the climate to the southwest and south are generally warm with uneven elevation due to a mix of highlands and mountain ranges; the drastic changes in climate alongside the Caspian have led to a great deal of biodiversity in the region. [9]

The Caspian Sea has numerous islands throughout, all of them near the coasts; none in the deeper parts of the sea. Ogurja Ada is the largest island. The island is 37 km (23 mi) long, with gazelles roaming freely on it. In the North Caspian, the majority of the islands are small and uninhabited, like the Tyuleniy Archipelago, an Important Bird Area (IBA), although some of them have human settlements.


Caspian Sea near Aktau, Mangystau Region, Kazakhstan Caspian Sea Kazakhstan Mangistau.jpg
Caspian Sea near Aktau, Mangystau Region, Kazakhstan

The Caspian has characteristics common to both seas and lakes. It is often listed as the world's largest lake, although it is not a freshwater lake. It contains about 3.5 times more water, by volume, than all five of North America's Great Lakes combined. The Caspian was once part of the Tethys Ocean, but became landlocked about 5.5 million years ago due to plate tectonics. [10] The Volga River (about 80% of the inflow) and the Ural River discharge into the Caspian Sea, but it has no natural outflow other than by evaporation. Thus the Caspian ecosystem is a closed basin, with its own sea level history that is independent of the eustatic level of the world's oceans.

The level of the Caspian has fallen and risen, often rapidly, many times over the centuries. Some Russian historians[ who? ] claim that a medieval rising of the Caspian, perhaps caused by the Amu Darya changing its inflow to the Caspian from the 13th century to the 16th century, caused the coastal towns of Khazaria, such as Atil, to flood. In 2004, the water level was 28 metres (92 feet) below sea level.

Over the centuries, Caspian Sea levels have changed in synchrony with the estimated discharge of the Volga, which in turn depends on rainfall levels in its vast catchment basin. Precipitation is related to variations in the amount of North Atlantic depressions that reach the interior, and they in turn are affected by cycles of the North Atlantic oscillation. Thus levels in the Caspian Sea relate to atmospheric conditions in the North Atlantic, thousands of miles to the northwest.[ citation needed ]

The last short-term sea-level cycle started with a sea-level fall of 3 m (10 ft) from 1929 to 1977, followed by a rise of 3 m (10 ft) from 1977 until 1995. Since then smaller oscillations have taken place. [16]

Environmental degradation

The Volga River, the largest in Europe, drains 20% of the European land area and is the source of 80% of the Caspian's inflow. Its lower reaches are heavily developed with numerous unregulated releases of chemical and biological pollutants. Although existing data is sparse and of questionable quality, there is ample evidence to suggest that the Volga is one of the principal sources of transboundary contaminants into the Caspian.

The magnitude of fossil fuel extraction and transport activity in the Caspian also poses a risk to the environment. The island of Vulf off Baku, for example, has suffered ecological damage as a result of the petrochemical industry; this has significantly decreased the number of species of marine birds in the area. Existing and planned oil and gas pipelines under the sea further increase the potential threat to the environment. [17]

The Vladimir Filanovsky field in the Russian section of the body of water was discovered for its wealth of oil in 2005. It is reportedly the largest discovery of oil in 25 years. It was announced in October 2016 that Lukoil would start production in this region. [18]


Iran's northern Caspian Hyrcanian mixed forests are maintained by moisture captured from the Caspian Sea by the Alborz Mountain Range. Ghaleye Rud Khan (40) 4.jpg
Iran's northern Caspian Hyrcanian mixed forests are maintained by moisture captured from the Caspian Sea by the Alborz Mountain Range.



The rising level of the Caspian Sea between 1994 and 1996 reduced the number of habitats for rare species of aquatic vegetation. This has been attributed to a general lack of seeding material in newly formed coastal lagoons and water bodies.[ citation needed ]


Most tadpole gobies (Benthophilus) are only found in the Caspian Sea basin. Benthophilus casachicus, Caspian Sea.jpg
Most tadpole gobies (Benthophilus) are only found in the Caspian Sea basin.

The Caspian turtle (Mauremys caspica), although found in neighboring areas, is a wholly freshwater species. The zebra mussel is native to the Caspian and Black Sea basins, but has become an invasive species elsewhere, when introduced. The area has given its name to several species, including the Caspian gull and the Caspian tern. The Caspian seal (Pusa caspica) is the only aquatic mammal and is endemic to the Caspian Sea, being one of very few seal species that live in inland waters, but it is different from the those inhabiting freshwaters due to the hydrological environment of the sea.

Archeological studies of Gobustan petroglyphs indicate that there once had been dolphins [20] and porpoises, [21] [22] or a certain species of beaked whales [23] and a whaling scene indicates large baleen whales [24] likely being present in Caspian Sea at least until when the Caspian Sea ceased being a part of the ocean system or until the Quaternary or much more recent periods such as until the last glacial period or antiquity. [25] Although the rock art on Kichikdash Mountain is assumed to be of a dolphin [26] or of a beaked whale, [23] it might instead represent the famous beluga sturgeon due to its size (430 cm in length), but fossil records suggest certain ancestors of modern dolphins and whales, such as Macrokentriodon morani (bottlenose dolphins) and Balaenoptera sibbaldina (blue whales) were presumably larger than their present descendants. From the same artworks, auks, like Brunnich's Guillemot could also have been in the sea as well, and these petroglyphs suggest marine inflow between the current Caspian Sea and the Arctic Ocean or North Sea, or the Black Sea. [26] This is supported by the existences of current endemic, oceanic species such as lagoon cockles which was genetically identified to originate in Caspian/Black Seas regions. [24]

The sea's basin (including associated waters such as rivers) has 160 native species and subspecies of fish in more than 60 genera. [19] About 62% of the species and subspecies are endemic, as are 4–6 genera (depending on taxonomic treatment). The lake proper has 115 natives, including 73 endemics (63.5%). [19] Among the more than 50 genera in the lake proper, 3–4 are endemic: Anatirostrum , Caspiomyzon , Chasar (often included in Ponticola ) and Hyrcanogobius . [19] By far the most numerous families in the lake proper are gobies (35 species and subspecies), cyprinids (32) and clupeids (22). Two particularly rich genera are Alosa with 18 endemic species/subspecies and Benthophilus with 16 endemic species. [19] Other examples of endemics are four species of Clupeonella , Gobio volgensis , two Rutilus , three Sabanejewia , Stenodus leucichthys , two Salmo , two Mesogobius and three Neogobius . [19] Most non-endemic natives are either shared with the Black Sea basin or widespread Palearctic species such as crucian carp, Prussian carp, common carp, common bream, common bleak, asp, white bream, sunbleak, common dace, common roach, common rudd, European chub, sichel, tench, European weatherfish, wels catfish, northern pike, burbot, European perch and zander. [19] Almost 30 non-indigenous, introduced fish species have been reported from the Caspian Sea, but only a few have become established. [19]

Six sturgeon species, the Russian, bastard, Persian, sterlet, starry and beluga, are native to the Caspian Sea. [19] The last of these is arguably the largest freshwater fish in the world. The sturgeon yield roe (eggs) that are processed into caviar. Overfishing has depleted a number of the historic fisheries. [27] In recent years, overfishing has threatened the sturgeon population to the point that environmentalists advocate banning sturgeon fishing completely until the population recovers. The high price of sturgeon caviar, however, allows fishermen to afford bribes to ensure the authorities look the other way, making regulations in many locations ineffective. [28] Caviar harvesting further endangers the fish stocks, since it targets reproductive females.



Many rare and endemic plant species of Russia are associated with the tidal areas of the Volga delta and riparian forests of the Samur River delta. The shoreline is also a unique refuge for plants adapted to the loose sands of the Central Asian Deserts. The principal limiting factors to successful establishment of plant species are hydrological imbalances within the surrounding deltas, water pollution, and various land reclamation activities. The water level change within the Caspian Sea is an indirect reason for which plants may not get established.

These affect aquatic plants of the Volga Delta, such as Aldrovanda vesiculosa and the native Nelumbo caspica . About 11 plant species are found in the Samur River Delta, including the unique liana forests that date back to the Tertiary period.[ citation needed ]


Illustration of two Caspian tigers, extinct in the region since the 1970s. Extantigerturanianwksciam97.jpg
Illustration of two Caspian tigers, extinct in the region since the 1970s.

Reptiles native to the region include spur-thighed tortoise (Testudo graeca buxtoni) and Horsfield's tortoise.


A New and Accurate Map of the Caspian Sea by the Soskam Sabbus & Emanuel Bowen, 1747. Bowen, Emanuel; Orbeliani, Sulxan-Saba. A new and accurate map of the Caspian Sea. 1747. (A).jpg
A New and Accurate Map of the Caspian Sea by the Soskam Sabbus & Emanuel Bowen, 1747.
Caspian Sea (Bahr ul-Khazar). 10th century map by Ibn Hawqal Caspian sea Ibn Hawqal.JPG
Caspian Sea (Bahr ul-Khazar). 10th century map by Ibn Hawqal

The history of the Caspian sea is divided into two parts: a Miocene stage, determined by tectonic events that correlate with the closing of the Tethys Sea, and a Pleistocene stage, that includes glaciation cycles and the creation of the present Volga River. During the first stage, the Tethys Sea had evolved into the Sarmatian Lake, that was created from the modern Black Sea and south Caspian, when the collision of the Arabian peninsula with Western Asia pushed up the Kopet Dag and Caucasus Mountains, setting definitive south and west boundaries to the Caspian basin. This orogeneic movement was continuous throughout the years, while Caspian was regularly disconnecting from the Black Sea. In the late Pontian, a mountain arch rose across the south basin and divided it in the Khachmaz and Lankaran Lakes (or early Balaxani). The period of restriction to the south basin was reversed during the Akchagyglian, when the lake expanded to more than three times its present area and established the first of a series of contacts with the Black Sea and with Lake Aral. A recession of the lake Akchagyl completed stage one. [31]

The 17th-century Cossack rebel and pirate Stenka Razin, on a raid in the Caspian (Vasily Surikov, 1906) Surikov1906.jpg
The 17th-century Cossack rebel and pirate Stenka Razin, on a raid in the Caspian (Vasily Surikov, 1906)

The earliest hominid remains found around the Caspian Sea are from Dmanisi dating back to around 1.8 Ma and yielded a number of skeletal remains of Homo erectus or Homo ergaster. More later evidence for human occupation of the region came from a number of caves in Georgia and Azerbaijan such as Kudaro and Azykh Caves. There is evidence for Lower Palaeolithic human occupation south of the Caspian from western Alburz. These are Ganj Par and Darband Cave sites.

Neanderthal remains also have been discovered at a cave site in Georgia. Discoveries in the Huto cave and the adjacent Kamarband cave, near the town of Behshahr, Mazandaran south of the Caspian in Iran, suggest human habitation of the area as early as 11,000 years ago. [32] [33]

The Caspian area is rich in energy resources. Oil wells were being dug in the region as early as the 10th century to reach oil "for use in everyday life, both for medicinal purposes and for heating and lighting in homes". [34] [ full citation needed ] By the 16th century, Europeans were aware of the rich oil and gas deposits around the area. English traders Thomas Bannister and Jeffrey Duckett described the area around Baku as "a strange thing to behold, for there issueth out of the ground a marvelous quantity of oil, which serveth all the country to burn in their houses. This oil is black and is called nefte. There is also by the town of Baku, another kind of oil which is white and very precious [i.e., petroleum]." [35] [ full citation needed ]

In the 18th century, during the rule of Peter I the Great, Fedor I. Soimonov, hydrographer and pioneering explorer of the Caspian Sea charted the until then little known body of water. Soimonov drew a set of four maps and wrote Pilot of the Caspian Sea, the first report and modern maps of the Caspian, that were published in 1720 by the Russian Academy of Sciences. [36]

Today, oil and gas platforms abound along the edges of the sea. [37]


Baku, the capital of Azerbaijan is the largest city by the Caspian Sea. View of night Baku, 2010.jpg
Baku, the capital of Azerbaijan is the largest city by the Caspian Sea.




Oil pipelines in the Caspian region. September 2002 Oil pipelines in the Caspian region.gif
Oil pipelines in the Caspian region. September 2002

Countries on the Caspian region, such as Azerbaijan, Kazakhstan and Turkmenistan, illustrate the examples of natural-resource-based economies. A resource-based economy is defined as one where the natural resources, gas and oil, compose more that 10 percent of the particular country's GDP and 40 percent of exports. [38] All the Caspian region economies are highly dependent on the mineral wealth. The world energy markets were influenced by Azerbaijan and Kazakhstan, as they became strategically crucial in this sphere, thus attracting the largest share of FDI (foreign direct investment).

Iran has an enormous energy potential based on several specific factors. It has reserves containing 137.5 billion bbl of crude oil, the second largest in the world, producing around 4 million bbl/day. Additionally, Iran has an estimated 988.4 trillion cubic feet of natural gas, around 16 percent of total world reserves, which makes it to play a key role in the global energy security equation. [39]

Russia's economy ranks as the twelfth largest by nominal GDP and sixth largest by purchasing power parity in 2015. [40] Russia's extensive mineral and energy resources are the largest such reserves in the world, [41] making it the second leading producer of oil and natural gas globally. [42]

Oil and gas

Drilling platform "Iran Khazar" in use at a Dragon Oil production platform in the Cheleken field (Turkmenistan). Jack-up-rig-in-the-caspian-sea.JPG
Drilling platform "Iran Khazar" in use at a Dragon Oil production platform in the Cheleken field (Turkmenistan).

The Caspian Sea region presently is a significant, but not major, supplier of crude oil to world markets, based upon estimates by BP Amoco and the U.S. Energy Information Administration, U.S. Department of Energy. The Caspian region produced an estimated 1.4–1.5 million barrels per day (bbls/day) including natural gas liquids in 2001, or 1.9% of total world output (table 1).3 More than a dozen non-Caspian countries each produce more than 1.5 million bbls/day. Caspian region production has been higher, but suffered during the collapse of the Soviet Union and the years following. Kazakhstan accounts for 55% and Azerbaijan for about 20% of current regional oil output. [43]

Caspian region oil and natural gas infrastructure. August 2013. Caspian region oil and natural gas infrastructure.png
Caspian region oil and natural gas infrastructure. August 2013.

The world's first offshore wells and machine-drilled wells were made in Bibi-Heybat Bay, near Baku, Azerbaijan. In 1873, exploration and development of oil began in some of the largest fields known to exist in the world at that time on the Absheron Peninsula near the villages of Balakhanli, Sabunchi, Ramana, and Bibi Heybat. Total recoverable reserves were more than 500 million tons. By 1900, Baku had more than 3,000 oil wells, 2,000 of which were producing at industrial levels. By the end of the 19th century, Baku became known as the "black gold capital", and many skilled workers and specialists flocked to the city.

By the beginning of the 20th century, Baku was the centre of international oil industry. In 1920, when the Bolsheviks captured Azerbaijan, all private property – including oil wells and factories – was confiscated. Afterwards, the republic's entire oil industry came under the control of the Soviet Union. By 1941, Azerbaijan was producing a record 23.5 million tons of oil per year, and the Baku region supplied nearly 72 percent of all oil extracted in the entire Soviet Union. [34]

In 1994, the "Contract of the Century" was signed, signalling the start of major international development of the Baku oil fields. The Baku–Tbilisi–Ceyhan pipeline, a major pipeline allowing Azerbaijan oil to flow straight to the Turkish Mediterranean port of Ceyhan, opened in 2006.


Baku, which is the starting point of all sea routes of Azerbaijan, is the largest port of the Caspian Sea. Azerbaijan has access to the oceans along the Caspian Sea-Volga-Volga-Don Canal, and the Don-Sea of Azov. Along with the Volga-Don Canal, the Azerbaijani vessels have the opportunity to enter the world ocean through the Volga-Baltic and White Sea-Baltic canals. Moreover, oil tankers are being transported through the Caspian Sea. Baku Sea Trade Port and Caspian Shipping Company CJSC, have a big role in the sea transportation of Azerbaijan. The Caspian Sea Shipping Company CJSC, along with the transport fleet, also includes a specialized fleet and shipyards. The transport fleet consists of 51 vessels, including 20 tankers, 13 ferries, 15 universal dry cargo vessels, 2 Ro-Ro vessels, as well as 1 technical vessel and 1 floating workshop. The specialized fleet includes 210 vessels, including 20 cranes, 25 towing and supplying vehicles, 26 passenger, two pipe-laying, six fire-fighting, seven engineering-geological, two diving and 88 auxiliary vessels. [44]

The Caspian Sea Shipping Company of Azerbaijan, which acts as a liaison in the Transport Corridor Europe-Caucasus-Asia (TRACECA), simultaneously with the transportation of cargo and passengers in the Trans-Caspian direction, also performs work to fully ensure the processes of oil and gas production at sea. This activity has a rich history. The development of the shipping industry in Azerbaijan is closely connected with the formation and progress of the oil industry. In the 19th century, the sharp increase in oil production in Baku gave a huge impetus to the development of shipping in the Caspian Sea, and as a result, there was a need to create fundamentally new floating facilities for the transportation of oil and oil products. [45]

Political issues

Many of the islands along the Azerbaijani coast continue to hold significant geopolitical and economic importance because of the potential oil reserves found nearby. Bulla Island, Pirallahı Island, and Nargin, which is still used as a former Soviet base and is the largest island in the Baku bay, all hold oil reserves.

The collapse of the Soviet Union and subsequent opening of the region has led to an intense investment and development scramble by international oil companies. In 1998, Dick Cheney commented that "I can't think of a time when we've had a region emerge as suddenly to become as strategically significant as the Caspian." [46]

A key problem to further development in the region is the status of the Caspian Sea and the establishment of the water boundaries among the five littoral states. The current disputes along Azerbaijan's maritime borders with Turkmenistan and Iran could potentially affect future development plans.

Much controversy currently exists over the proposed Trans-Caspian oil and gas pipelines. These projects would allow Western markets easier access to Kazakh oil and, potentially, Uzbek and Turkmen gas as well. Russia officially opposes the project on environmental grounds. [47] However, analysts note that the pipelines would bypass Russia completely, thereby denying the country valuable transit fees, as well as destroying its current monopoly on westward-bound hydrocarbon exports from the region. [47] Recently, both Kazakhstan and Turkmenistan have expressed their support for the Trans-Caspian Pipeline. [48]

U.S. diplomatic cables disclosed by WikiLeaks revealed that BP covered up a gas leak and blowout incident in September 2008 at an operating gas field in the Azeri-Chirag-Guneshi area of the Azerbaijan Caspian Sea. [49] [50]

Territorial status

Southern Caspian Energy Prospects (portion of Iran). Country Profile 2004. Iran southern caspian energy prospects 2004.jpg
Southern Caspian Energy Prospects (portion of Iran). Country Profile 2004.
Caspian Sea, Azerbaijan Baku Bulvar.jpg
Caspian Sea, Azerbaijan

As of 2000, negotiations related to the demarcation of the Caspian Sea had been going on for nearly a decade among the states bordering the Caspian – Azerbaijan, Russia, Kazakhstan, Turkmenistan, and Iran. The status of the Caspian Sea [51] is the key problem. Access to mineral resources (oil and natural gas), access for fishing, and access to international waters (through Russia's Volga river and the canals connecting it to the Black Sea and Baltic Sea) all depend upon the outcomes of negotiations. Access to the Volga River is particularly important for the landlocked states of Azerbaijan, Kazakhstan, and Turkmenistan. This concerns Russia, because the potential traffic would use its inland waterways. If a body of water is labelled as a sea, then there would be some precedents and international treaties obliging the granting of access permits to foreign vessels. If a body of water is labelled merely as a lake, then there are no such obligations. Environmental issues are also somewhat connected to the status and borders issue.

All five Caspian littoral states maintain naval forces on the sea. [52]

According to a treaty signed between Iran and the Soviet Union, the Caspian Sea is technically a lake and was divided into two sectors (Iranian and Soviet), but the resources (then mainly fish) were commonly shared. The line between the two sectors was considered an international border in a common lake, like Lake Albert. The Soviet sector was sub-divided into the four littoral republics' administrative sectors.

Russia, Kazakhstan, and Azerbaijan have bilateral agreements with each other based on median lines. Because of their use by the three nations, median lines seem to be the most likely method of delineating territory in future agreements. However, Iran insists on a single, multilateral agreement between the five nations (as this is the only way for it to achieve a one-fifth share of the sea). Azerbaijan is at odds with Iran over some oil fields that both states claim. Occasionally, Iranian patrol boats have fired at vessels sent by Azerbaijan for exploration into the disputed region. There are similar tensions between Azerbaijan and Turkmenistan (the latter claims that the former has pumped more oil than agreed from a field, recognized by both parties as shared).

The Caspian littoral states' meeting in 2007 signed an agreement that bars any ship not flying the national flag of a littoral state from entering the sea. [53]

Negotiations among the five littoral states have been ongoing, amidst ebbs and flows, for the past 20 years, with some degree of progress being made at the fourth Caspian Summit held in Astrakhan in 2014. [54]

Caspian Summit

The Caspian Summit is a head of state-level meeting of the five littoral states. [55] The fifth Caspian Summit took place on August 12, 2018 in the Kazakh port city of Aktau. [55] The five leaders signed the ‘Convention on the Legal Status of the Caspian Sea’. [56]

The five littoral states build consensus on legally binding governance of the Caspian Sea through Special Working Groups of a Convention on the Legal Status of the Caspian Sea. [57] In advance of a Caspian Summit, 51st Special Working Group took place in Astana in May 2018 and found consensus on multiple agreements: Agreements on cooperation in the field of transport; trade and economic cooperation; prevention of incidents on the sea; combating terrorism; fighting against organized crime; and border security cooperation. [58]

The Convention grants jurisdiction over 15 miles of territorial waters to each neighboring country, plus additional 10 miles of exclusive fishing rights on the surface, while the rest is international waters. The seabed, on the other hand, remains undefined, subject to bilateral agreements between countries. Thus, the Caspian Sea is legally neither fully a sea nor a lake. [59]

Crossborder inflow

UNECE recognizes several rivers that cross international borders which flow into the Caspian Sea. [60] These are:

Atrek River Iran, Turkmenistan
Kura River Armenia, Azerbaijan, Georgia, Iran, Turkey
Ural River Kazakhstan, Russia
Samur River Azerbaijan, Russia
Sulak River Georgia, Russia
Terek River Georgia, Russia


Although the Caspian Sea is endorheic, its main tributary, the Volga, is connected by important shipping canals with the Don River (and thus the Black Sea) and with the Baltic Sea, with branch canals to Northern Dvina and to the White Sea.

Another Caspian tributary, the Kuma River, is connected by an irrigation canal with the Don basin as well.

Several scheduled ferry services (including train ferries) operate on the Caspian Sea, including:

The ferries are mostly used for cargo; only the Baku–Aktau and Baku–Türkmenbaşy routes accept passengers.


As an endorheic basin, the Caspian Sea basin has no natural connection with the ocean. Since the medieval period, traders reached the Caspian via a number of portages that connected the Volga and its tributaries with the Don River (which flows into the Sea of Azov) and various rivers that flow into the Baltic Sea. Primitive canals connecting the Volga Basin with the Baltic have been constructed as early as the early 18th century. Since then, a number of canal projects have been completed.

The two modern canal systems that connect the Volga Basin, and hence the Caspian Sea, with the ocean are the Volga–Baltic Waterway and the Volga–Don Canal.

The proposed Pechora–Kama Canal was a project that was widely discussed between the 1930s and 1980s. Shipping was a secondary consideration. Its main goal was to redirect some of the water of the Pechora River (which flows into the Arctic Ocean) via the Kama River into the Volga. The goals were both irrigation and the stabilization of the water level in the Caspian, which was thought to be falling dangerously fast at the time. During 1971, some peaceful nuclear construction experiments were carried out in the region by the U.S.S.R.

In June 2007, in order to boost his oil-rich country's access to markets, Kazakhstan's President Nursultan Nazarbayev proposed a 700-kilometre (435-mile) link between the Caspian Sea and the Black Sea. It is hoped that the "Eurasia Canal" (Manych Ship Canal) would transform landlocked Kazakhstan and other Central Asian countries into maritime states, enabling them to significantly increase trade volume. Although the canal would traverse Russian territory, it would benefit Kazakhstan through its Caspian Sea ports. The most likely route for the canal, the officials at the Committee on Water Resources at Kazakhstan's Agriculture Ministry say, would follow the Kuma–Manych Depression, where currently a chain of rivers and lakes is already connected by an irrigation canal (Kuma–Manych Canal). Upgrading the Volga–Don Canal would be another option. [61]

See also

Related Research Articles

Geography of Azerbaijan

Azerbaijan is situated in the Caucasus region of Eurasia. Three physical features dominate Azerbaijan: the Caspian Sea, whose shoreline forms a natural boundary to the east; the Greater Caucasus mountain range to the north; and the extensive flatlands at the country's center. About the size of Portugal or the state of Maine, Azerbaijan has a total land area of approximately 86,600 square kilometers, less than 0.5% of the land area of the former Soviet Union. Of the three Transcaucasian states, Azerbaijan has the greatest land area. Special administrative subdivisions are the Nakhchivan Autonomous Republic, which is separated from the rest of Azerbaijan by a strip of Armenian territory, and the Nagorno-Karabakh Autonomous Region, entirely within Azerbaijan.

Transport in Turkmenistan includes such as roadways, railways, airways, seaways, waterways, oil, gas and water pipelines.

Transport in Azerbaijan

The transport in Azerbaijan involves air traffic, waterways and railroads. All transportation services in Azerbaijan except for oil and gas pipelines are regulated by the Ministry of Transportation of Azerbaijan Republic.

Kura (Caspian Sea) river in Caucasia

The Kura is an east-flowing river south of the Greater Caucasus Mountains which drains the southern slopes of the Greater Caucasus east into the Caspian Sea. It also drains the north side of the Lesser Caucasus while its main tributary, the Aras drains the south side of those mountains. Starting in northeastern Turkey, it flows through Turkey to Georgia, then to Azerbaijan, where it receives the Aras as a right tributary, and enters the Caspian Sea at Neftçala. The total length of the river is 1,515 kilometres (941 mi).

Baku–Tbilisi–Ceyhan pipeline oil pipeline

The Baku–Tbilisi–Ceyhan (BTC) pipeline is a 1,768 kilometres (1,099 mi) long crude oil pipeline from the Azeri–Chirag–Gunashli oil field in the Caspian Sea to the Mediterranean Sea. It connects Baku, the capital of Azerbaijan and Ceyhan, a port on the south-eastern Mediterranean coast of Turkey, via Tbilisi, the capital of Georgia. It is the second-longest oil pipeline in the former Soviet Union, after the Druzhba pipeline. The first oil that was pumped from the Baku end of the pipeline reached Ceyhan on 28 May 2006.

Ceyhan District in Mediterranean, Turkey

Ceyhan is a city and a district in the Adana Province, in southern Turkey, 43 km (27 mi) east of Adana. With a population of over 157,000, it is the largest district of the province, outside the city of Adana. Ceyhan is the transportation hub for Middle Eastern, Central Asian and Russian oil and natural gas. The city is situated on the Ceyhan River that flows through Çukurova plain. The Ceyhan River is dammed at Aslantas to provide flood control and irrigation for the lower river basin around Ceyhan.

Caspian Depression A low-lying flatland region encompassing the northern part of the Caspian Sea

The Caspian Depression or Pricaspian/Peri-Caspian Depression/Lowland is a low-lying flatland region encompassing the northern part of the Caspian Sea, the largest enclosed body of water on Earth. It is the larger northern part of the wider Aral-Caspian Depression around the Aral and Caspian seas.

South Caucasus Pipeline gas pipeline

The South Caucasus Pipeline is a natural gas pipeline from the Shah Deniz gas field in the Azerbaijan sector of the Caspian Sea to Turkey. It runs parallel to the Baku–Tbilisi–Ceyhan pipeline (oil).

Trans-Caspian Gas Pipeline pipeline

The Trans-Caspian Gas Pipeline is a proposed subsea pipeline between Türkmenbaşy in Turkmenistan, and Baku in Azerbaijan. According to some proposals it will also include a connection between the Tengiz Field in Kazakhstan, and Türkmenbaşy. The Trans-Caspian Gas Pipeline project is purposed to transport natural gas from Turkmenistan and Kazakhstan to European Union member countries, circumventing both Russia and Iran. It is also considered as a natural eastward extension of Southern Gas Corridor. This project attracts significant interest since it will connect vast Turkmen gas resources to major consumer geographies as Turkey and Europe.

The Trans-Caspian Oil Transport System is a proposed project to transport oil through the Caspian Sea from Kazakhstani Caspian oilfields to Baku in Azerbaijan for the further transportation to the Mediterranean or Black Sea coast. The main options under consideration are an offshore oil pipeline from Kazakhstan to Azerbaijan, and construction of oil terminals and oil tankers fleet. A strong push for the project has been from the partners of the Kashagan oilfield project and in particular Total who has a share in both the field and the BTC pipeline. They have estimated that such a project would cost roughly US$4 billion. The project also faces opposition from Iran and Russia, both alternative avenues for Kazakhstan's oil and gas who would likely object to competing pipelines being built.

Central Asia–Center gas pipeline system Gazprom pipeline in Turkmenistan, Uzbekistan, Kazakhstan and Russia

The Central Asia – Center gas pipeline system is a Gazprom controlled system of natural gas pipelines, which run from Turkmenistan via Uzbekistan and Kazakhstan to Russia. The eastern branch includes the Central Asia - Center (CAC) 1, 2, 4 and 5 pipelines, which start from the south-eastern gas fields of Turkmenistan. The western branch consists of the CAC-3 pipeline and a project to build a new parallel Caspian pipeline. The western branch runs from the Caspian Sea coast of Turkmenistan to north. The branches meet in western Kazakhstan. From there the pipelines run to north where they are connected to the Russian natural gas pipeline system.

Absheron Peninsula Place

The Absheron Peninsula is a peninsula in Azerbaijan. It is the location of Baku, the biggest and the most populous city of the country, and also the Baku metropolitan area, with its satellite cities Sumqayit and Khyrdalan.

Caspian pipeline may refer to:

The Neka–Jask pipeline is a proposed oil pipeline in Iran. If constructed, it will transport crude oil from Kazakhstan, Azerbaijan, Turkmenistan and Russia through the port of Neka on the Caspian Sea to Jask, Iran on the Gulf of Oman. The planned capacity of the 1,515 kilometres (941 mi) pipeline is 1 million barrels per day of crude oil. It is expected to cost US$2 billion.

The Manych Ship Canal is a canal system between the basins of the Sea of Azov, Black Sea, and Caspian Sea. Proposals are being considered to expand the system into a larger Eurasia Canal system. The canal would be a multipurpose water-resources system and an important part of the national transport system serving internal and international Caspian oil traffic, with huge economic potential for the region. A proposed design would enlarge the Manych Ship Canal to a depth of 6.5 m (21 ft) and width of 80 m (260 ft) with traffic capacity for more than 75 million tons per year. This proposed Eurasia Canal would allow passage of vessels with a freight-carrying capacity of up to 10,000 tons. Russia's unique geographic location and transportation infrastructure does not correspond economically to the current logistics of Russian and foreign trade.

Chirag is an offshore oil field in the Caspian Sea, located 120 km (75 mi) east of Baku, Azerbaijan and is a part of the larger Azeri-Chirag-Guneshli (ACG) project. The production, drilling and quarters (PDQ) platform Chirag 1 (EOP) has been in operation since 1997. Chirag 1 has been producing the Early Oil from the ACG field. West Chirag is planned as an extension of ACG project.

<i>Ponticola gorlap</i> species of fish

Ponticola gorlap, or the Caspian bighead goby, is a species of goby, a benthic fish native to the Caspian Sea basin. It is widespread in lower parts of many rivers in Iran, and also found in Azerbaijan and Turkmenistan. In Russia, it occurred in the lowest part of the Volga River up to Astrakhan until 1977, but has thereafter spread upstream. In 2000 it was recorded as being established in the Ivankovo and Rybinsk Reservoirs in the Moscow region, and already invaded the Don drainage by way of the Volga-Don Canal in 1972. This species occurs in sheltered environments, such as inshore fresh or brackish waters of estuaries, lagoons, lakes and large rivers, where it prefers habitats with a well vegetated rock or firmly packed sand substrate. It can reach a length of 20 centimetres (7.9 in) SL, and a common size is 12 centimetres (4.7 in) SL.

Azerbaijan in World War II

Azerbaijan, officially by its full name – the Azerbaijan Soviet Socialist Republic, entered World War II alongside the Soviet Union, after the German declaration of war on June 22, 1941. Azerbaijan's oilfields were enticing to the Germans due to the USSR's heavy dependency on Caucasus oil – setting the scene for German campaigns attempting to capture and seize the oilfields in Baku during the Battle of the Caucasus. More than 600,000 people from Azerbaijan were conscripted to the Workers’ and Peasants’ Red Army during World War II from 1941 to 1945.

Borders of Azerbaijan political border

The Borders of Azerbaijan define the land and maritime borders of Azerbaijan. Azerbaijan has international land borders with 5 states.

The Azerbaijan is a country with very favorable natural conditions and rich natural resources. Snowy peaks, high mountains, foothill fertile soils, wide plains, Lowest Land Points Below Ocean Level are the main landscape forms of republic. This complex landscape structure has caused the variety in natural conditions - climate, soil-vegetation, and water resources. This, in turn, led to the uneven distribution of population and farms on the territory, and the specialization of production on different types.


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