Why is it called the Caspian Sea if it is a lake

The Caspian Sea, formerly known as Caspium Mare or Hyrcanium Mare , is not a true sea, but is actually a lake. The Caspian Sea is the largest lake in the world with a total area of ​​371,000 km ² (somewhat larger than Germany) and a volume of 78,200 km ³ . This immense lake is located between two continents; Asia and Europe. Its waters bathe several countries, including Russia and Azerbaijan to the west, Kazakhstan to the north and northeast, Turkmenistan to the east and finally, Iran to the south.

Geographically it is located in the western part of the uralocasp depression and is part of the largest endorheic basin that exists on the earth’s surface . As it is an endorheic basin, the water in this lake has no outlet, neither towards other basins nor towards the sea, nor does it infiltrate the ground, so the only possible loss of water is due to evaporation. This makes the lake rich in salts and, therefore, and although it is a lake, its waters are salty . There is a small artificial connection to the Sea of ​​Azov through the Manych Canal.

The Caspian Sea is fed by the waters of the Volga, Ural, Emba and Kura rivers . The coast of the Caspian Sea is irregular, has large gulfs to the east and is surrounded by high mountain ranges (Elburz and the Greater Caucasus) on the south and southwest coast.

The Caspian Sea measures approximately 1,210 km from north to south and between 210 and 436 km from west to east. In addition, it has an average depth of about 170 m but the deepest areas located in the southern part of the lake can reach 995 or even 1,025 m. Although its water level can vary from year to year, it is usually 28 meters below sea level.

Regarding the biology of the Caspian Sea, it is worth highlighting the presence of the sturgeon ( Acipenser sturio ), especially famous for the important gastronomic value of its roe and commonly known as caviar. Due to their overfishing, sturgeon populations have decreased considerably in recent years and various environmental initiatives have emerged that support the prohibition of sturgeon fishing. Another characteristic species of these waters is the Caspian seal ( Phoca caspica or Pusa caspica ), an endemic aquatic mammal of the Caspian Sea.

To understand the nature of the waters of the Caspian Sea it is necessary to look back and go back to its origins. 30 million years ago the Caspian Sea was linked to the oceans and seas that bathed southwest Asia, like the Paratetis Sea. Later, about 5.5 million years ago, the European continent began to rise and its waters were separated from the ocean. In the beginning and after the rise of the Caucasus and Elburz Mountains, the Caspian Sea and Black Sea basins were united, but finally the elevation of the Caucasus Mountains completely isolated the waters of the Caspian Sea. This isolation together with the unique environmental conditions of this lake favored the radiation of new species due to the triggering of new evolutionary processes.

Due to its origin the waters are slightly salty . Its salinity is one third of the salinity of the water found in the oceans, or what is to say, 1.2% of the salinity of the ocean. In addition, this lake has a high evaporation rate, so the salts accumulate in the remaining water, increasing its salinity.

Countries whose waters are washed by the Caspian Sea have needed to regulate the reserves of natural resources found in it. There are three resources of special importance and that could become a source of conflict if not properly regulated:

• Mineral and energy resources (oil and natural gas).
• Fishing resources.
• Access to international waters (Volga River and the canals that connect to the Black Sea and the Baltic Sea)

Legally, if a body of water is considered sea, international treaties would force access to foreign ships to be guaranteed. However, these obligations disappear when it comes to a lake. In addition, this would mean that if the neighboring countries are sea, the resources of the bottom should be distributed according to the size of their coasts and, since it is a lake, the resources should be distributed proportionally among the surrounding countries.

In the particular case of the Caspian Sea, there is an added problem that concerns all the countries that use its waters, as well as that of its tributary rivers. Since the waters of this lake naturally have no outlets , this system is very susceptible to water contamination . The water remains in the lake for a long time and therefore the entry of a dangerous pollutant into the lake would remain for a long time and could seriously damage the health of the ecosystem. The potential threats are mainly related to:

• Oil extraction (extraction platforms, spills).
• Construction of artificial islands.
• Intense and uncontrolled agricultural and industrial activity.