Today we are going to talk about a sea that receives this name but which is an endorheic lake of brackish water. Its about Caspian SeaThe Caspian Sea is a body of water completely surrounded by land and with no direct access to the sea or ocean. Therefore, according to the geological definition, it is a shore, not a sea. It has a certain level of salinity and is classified as the largest inland lake or endorheic basin in the world. At the same time, it is considered the smallest sea in the world.
Therefore, we are going to dedicate this article to tell you all the characteristics, geology and curiosities of the Caspian Sea.
Key features
When considering the Caspian Sea or lake, one must also look at the legal aspect. For example, if it will be considered a sea by the countries that limit it, and the natural resources that exist in its funds would be the property of the coast of each country. Otherwise, if we are talking about a lake, the resources of the bottom will be divided equally among the riparian countries.
The Caspian Sea lies east of the Caucasus Mountains in a deep depression between Europe and Asia. We are roughly 28 meters below sea level. The riparian countries surrounding the Caspian Sea are Iran, Azerbaijan, Turkmenistan, Russia, and Kazakhstan. This sea is made up of 3 basins: central or middle north and the southern basin.
The first basin is the smallest, covering just over a quarter of the sea's total area. It is also the shallowest part of the sea. The central basin is approximately 190 meters deep, allowing for a greater abundance of natural resources, although the deepest basin is the southern one. The southern basin holds two-thirds of the Caspian Sea's total water volume.
The total width of this sea is on average about 230 kilometers. At the widest point it is capable of measuring 435 kilometers and its maximum length is approximately 1030 kilometers. The deepest part is an area where the terrain abruptly rises to a depth of 1.025 meters. The approximate total area of the sea is 371000 square kilometers with a water volume of 78.200 cubic kilometersIt can be said that this sea contains more than 40% of all the world's continental waters. Although it has no outlet to the sea, there was no ocean, it is fed by multiple rivers that flow into it.
Among the most important rivers that flow into this sea are the Ural, the Terek, the Atrak, and the Kura. This is one of the reasons why it's known as a sea, since so many rivers flow into it. Also, if you're interested in learning more about other seas of asia, this article may be of interest to you.
Formation of the Caspian Sea
The waters of this sea are slightly salty, although only about a third of the salinity of ocean water. This is due to the percentage of water that evaporates since it is quite high in some areas.
When the evil called Paratetis was formed about 5.5 million years ago, it lost its connection with the sea and was totally isolated after a decrease in the water level and the lifting of the earth's crust that formed nearby mountains. These mountains are the Caucasus and the Elburz. At the beginning of the formation of the Caspian Sea, it formed a single basin together with the Black Sea and reached its maximum extent during the time of the PaleoceneIt was during this time that the Caucasus Mountains experienced a great uplift, which favored the separation of the basin into two distinct bodies. This caused the Caspian Sea to become completely isolated. To better understand its geological environment, I recommend exploring more about the caucasus mountains.
Biodiversity and threats of the Caspian Sea
As you might expect, the Caspian Sea is part of a large amount of biodiversity. In it there are more than 850 species of animals and more than 500 species of plants Thanks to these unique formation conditions, it has been declared that approximately 400 endemic species of animals are housed and many more that coexist in the deltas of the rivers and the coasts.
Some animal species that we can find in the Caspian Sea are: the seal, being one of the most iconic animals since they are not found anywhere else on earth since it is an endemic species. We also have a large number of fish such as perch, pike, herring, castle whitefish, sprat, bream and sturgeon. The sturgeon is one of the fish that gives the most money to the surrounding countries since its roe is served as caviar. The sturgeon fishery in this sea represents almost 90% of its world catch.
If we go to the underwater part of the ecosystem we can also observe the existence of various types of mollusks and crustaceans, as well as some reptiles. We find the Russian tortoise, the black tortoise, among others. On the surface and around the sea, some birds also nest and overwinter, such as the Caspian gull, the common coot, the common swan, the common goose, the mallard, the whooper swan and the imperial eagle, Among others.
On the vegetation side, we find some species of red and brown algae found in the deepest part of the sea and in some areas of the coast. In the areas closest to the shore, some xerophytic plants grow favorably. Some of these plants are adapted to drier soils. For those interested in the relationship between global warming and the Caspian Sea, you can find valuable information at this link.
Threats
As expected, this sea is threatened by human economic activities. This sea basin is rich in oil and natural gas deposits. These natural resources are the most important in the entire region. Production has increased in recent decades in line with demand. Together with sturgeon fishing they contribute to great economic growth that also causes impacts on the environment.
This is due to water pollution caused by the construction of extraction platforms, artificial islands, and other structures necessary to extract these natural resources and the discharge of toxic substances from agriculture and livestock farming.
There are also constant threats of oil spills. Given the enclosed nature of the sea, the Caspian Sea is highly vulnerable to pollution. For more details on how the climate change impacts the seas, you can consult our related article.
I hope that with this information you can learn more about the Caspian Sea.