The Caspian Sea is the Earth’s largest inland body of water. It lies at the junction of Europe and Asia, with the Caucasus Mountains to the west and the steppes of Central Asia to the east. It is bordered by Russia to the northwest, Azerbaijan to the west, Iran to the south, Turkmenistan to the southeast and Kazakhstan to the northeast.
Ownership of the sea’s resources is a contentious issue among its surrounding countries. The Caspian Sea is rich with oil and natural gas, making access to it a high-stakes proposition. These complicated socio-cultural and political aspects, as well as the geographic and environmental features, make the Caspian Sea an interesting subject for researchers.
Despite its name, the Caspian Sea can be called either a lake or a sea. Kukral refers to it as a lake, as do many scholars. It has historically been considered a sea because of its size and its saline water, but it embodies many characteristics of lakes. Much of the confusion comes because there are no internationally agreed-upon definitions for seas or lakes.
Seas are often defined by connection to the ocean or another sea via salt water, which the Caspian Sea is not. Seas are usually partially enclosed by land, according to the National Oceanic and Atmospheric Administration, but the Caspian Sea is entirely enclosed by land. Seas are typically salt water. While the Caspian Sea is not fresh water, its salty water is diluted by the inflow of fresh water, especially in the north.
The question of whether it is a lake or a sea has political and economic ramifications, wrote Hanna Zimnitskaya in a 2011 Journal of Eurasian Studies article. If the Caspian Sea is a lake, then the United Nations and international law have no control over its waters, she wrote. If it is a sea, international organizations can have input on its use.
This is especially important because its energy resources. “Petroleum resources around and under the Caspian Sea make it an economic natural resource and a political issue of access and ownership,” Kukral said.
If the Caspian Sea is a lake, it contains 40 percent of all lake water in the world. “It is the world’s largest lake,” Kukral said.
History The Caspian Sea is a remnant of the ancient Paratethys Sea, part of the Tethys Ocean that existed 50 million to 60 million years ago. At that time, the Tethys Ocean was connected to the Atlantic and Pacific oceans, according to WorldLakes.org. Over millennia, continental platforms shifted, and the Tethys Ocean lost its connections to other oceans. Much of it evaporated during hot and dry periods, and eventually the Caspian Sea, the Black Sea and the Aral Sea formed. The Caspian Sea is estimated to be about 30 million years old. The salt water from the Tethys Sea remained and accounts for the Caspian Sea’s salinity.
According to the New World Encyclopedia, archaeologists estimate that humans inhabited the area around 75,000 years ago. It is named after the Caspi Tribe, which settled on its southwestern shore. By the 10th century, small oil wells dotted the shores of the Caspian Sea, according to the State Oil Company of Azerbaijan Republic (SOCAR). Europeans learned of the resource-rich area and began traveling to the Caspian Sea to investigate in the 16th century. The first offshore oil well was drilled in 1820. Today, the oil and gas industry is prominent in the area. Other businesses include salt extraction, fishing and tourism along the coasts.
The water level of the Caspian Sea has fluctuated throughout history, according to GRID-Arendal. From the mid-19th to late 20th century, the water level varied by more than 12 feet (3.6 m). In 1977, the Caspian Sea flooded and caused widespread destruction. Since then, several more floods have occurred. Since 1978, the water level has risen almost 7.4 feet (2.2 m), according to the Pars Times.
The eggs of beluga sturgeons, the largest freshwater fish, are the source of beluga caviar. The majority of the world’s beluga caviar comes from the Caspian Sea. (Image credit: Mick Rush/Shutterstock) Ecosystem The Caspian Sea is known for its biodiversity, Kukral said. It is considered an independent zoogeographical region because of its unique qualities, according to the World Wildlife Fund.
In many areas, the shores are dotted with shallow saline pools in which birds, small fish, crustaceans and invertebrates thrive. Birds are present throughout the year, and many species use the Caspian Sea as a migratory refuge. Nearly 2,000 species and subspecies of animals live in and around the Caspian Sea, according to Casp Info. About 400 of them are endemic to the area, including the Caspian gull, Caspian turn, spur-thighed tortoise, Horsfield’s tortoise, Caspian white fish, Caspian salmon and Caspian seal, the only aquatic mammal in the area. Nearby petroglyphs suggest that dolphins and porpoises may have once lived in the Caspian Sea, according to the Smithsonian Institution.
The most famous and financially valuable animal in the region is the beluga sturgeon, sometimes called the European or Caspian sturgeon. The world’s largest freshwater fish, the beluga sturgeon is known for its eggs, which are processed into caviar. The majority of the world’s beluga caviar comes from the Caspian Sea. This has caused problems with overfishing. Dams have also destroyed much of their spawning grounds, and pesticides used in land agriculture have limited their fertility. The beluga sturgeon is now critically endangered, according to the World Wildlife Fund.
The Volga River Delta in the North Caspian is home to a wide range of endemic or rare aquatic plants, according to the World Wildlife Fund. The vegetation in the Turkmenistan portion of the Caspian shores is considered impoverished. Nevertheless, there are some specialized salt-resistant plants like shrubs and sagebrush.
Threats The Caspian Sea faces many ecological threats that have ramifications on human residents of the area, flora and fauna, the economy and the overall ecosystem. “Like all international inland bodies of water the questions today are about access, usage, pollutants/water quality and resources,” Kukral said.
The intensive oil and gas development in the Caspian region has caused serious water, air and land pollution problems, natural resources depletion, harm to wildlife and plant life, ecosystem disturbance, desertification and loss of biological and landscape diversity, according to Casp Info. Oil spills, waste from onshore industrial and municipal sites and chemicals, untreated sewage and trash carried in from rivers are major causes of land and water pollution. About 1 million cubic meters (264 million gallons) of untreated industrial wastewater is dumped into the Caspian each year, according to the Pars Times.
The rising sea levels have caused flooding, and as the water washes over shoreline oil wells, it carries oil and other pollutants inland. Scientists estimate that the on- and off-shore drilling operations in the Caspian area emit 15 to 20 million tons of CO2-equivalent each year, according to GRID-Arendal. This has led to serious air pollution problems in the area.
The environmental damage has led to serious health problems for residents of the five countries around the Caspian Sea, who ingest pollutants through air, drinking water, food and swimming. According to the Pars Times, Caspian-area Kazakhstan sees four times the rate of blood diseases, tuberculosis and intestinal infections than other parts of the country. Rates of cancer around the Caspian Sea are also higher than average in all five countries. During the Soviet era, the cities of Sumgayit and Baku were heavily industrialized. Today, the sea around these cities is an ecological dead zone. Human stillbirths and miscarriages happen at higher levels than in inland areas.
Addressing any of these problems is extremely difficult because of ownership disputes between the five countries. “Who is responsible to manage the water quality? Five countries share the Caspian Sea but who benefits from the oil? Where are the boundaries or jurisdiction within the lake?” Kukral said. These persistent questions are hard to answer and often undermine efforts at cooperative.