Rivers And Seas Of The World Codexery

Caspian Sea

Last updated

Caspian Sea

NASA · Public domain

It covers 371,000 km² and has a salinity of about 1.2%, roughly one-third that of average seawater.[1] The Caspian Sea, which is roughly the size of Japan, is the planet's biggest inland water expanse and is commonly classified as both the largest lake and a genuine sea.[2][3] Five nations—Azerbaijan, Iran, Kazakhstan, Russia, and Turkmenistan—have coastlines along this body of water.[4][5]

Geography and history

The sea is a remnant of the ancient Paratethys Sea, with a seafloor of oceanic basalt about 30 million years old.[6][7] The Southern Caspian reaches oceanic depths of over 1,000 meters.[8][9] The sea level has fluctuated rapidly over centuries, falling 3 meters from 1929 to 1977 and rising 3 meters from 1977 to 1995.[10] Tectonic uplift and a drop in sea level caused the Caspian to become landlocked during the Late Miocene epoch, roughly 5.5 million years ago.[6][7]

With an average depth of just 5 to 6 meters, the Northern Caspian holds less than 1% of the sea's total water volume.[11] A record low for the Caspian was observed in July 2025, when its surface dropped to more than 29 meters below sea level.[12]

What the cited sources add

A 2019 article in The Nation reports that the Caspian seal population has declined from over one million a century ago to fewer than 10% today.[3] The same source notes that sturgeon populations have declined by more than 90% over the last three generations, according to the World Wildlife Fund.[3] The UN Environment Programme warns that the Caspian suffers from pollution from oil extraction, radioactive wastes, and untreated sewage introduced mainly by the Volga River.[3][13] A 2025 paper by Court et al. projects that under medium to high emission scenarios, water levels could decline by up to 18 meters, converting up to 143,000 km² to land.[14][15]

A 2011 paper by Kazmin and Verzhbitskii confirms the South Caspian Basin's origin as a remnant of the Paratethys Sea.[6][7] According to the same paper, during the Akchagylian period the lake expanded to over three times its present size and re-established connections with the Black Sea and the Aral Sea.[16][17]

References

  1. Wikipedia, "Caspian Sea" (CC BY-SA 4.0), which cites: Leong, "Certificate Physics And Human Geography; Indian Edition", Oxford University Press, 1995-10-27, p. 66 (original not read by us) en.wikipedia.org
  2. Wikipedia, "Caspian Sea" (CC BY-SA 4.0), which cites: "Convention on the Legal Status of the Caspian Sea", President Of Russia, 2018-08-12; "Is the Caspian a sea or a lake?", The Economist, 2018-08-16; Zimnitskaya, "Is the Caspian Sea a Sea; and Why Does it Matter?", Journal of Eurasian Studies, January 2011, p. 1–14 (original not read by us) en.wikipedia.org
  3. "Caviar pool drains dry as Caspian Sea slides towards catastrophe", The Nation, 2019-04-18. facts only, no text reused. nationthailand.com
  4. Wikipedia, "Caspian Sea" (CC BY-SA 4.0), which cites: Hooshang Amirahmadi, "The Caspian Region at a Crossroad: Challenges of a New Frontier of Energy and Development", Palgrave Macmillan, 2000, p. 112– (we also read that source) en.wikipedia.org
  5. Open Library record, ISBN 9780312223519 ("The Caspian region at a crossroad"). CC0 (metadata); book content not read. openlibrary.org
  6. Wikipedia, "Caspian Sea" (CC BY-SA 4.0), which cites: Kaz’min, "Age and origin of the South Caspian Basin", Oceanology, 2011, p. 131–140; "Caspian Sea: Largest Inland Body of Water", Live Science, 24 February 2017 (we also read that source) en.wikipedia.org
  7. Vladimir G. Kazmin, "Age and origin of the South Caspian Basin", Oceanology (2011), doi:10.1134/s0001437011010073. OpenAlex metadata CC0; paper not read. doi.org
  8. Wikipedia, "Caspian Sea" (CC BY-SA 4.0), which cites: "Aquatic Invasions in the Black, Caspian, and Mediterranean Seas", Springer, 2004 (we also read that source) en.wikipedia.org
  9. Open Library record, ISBN 9781402018695 ("Aquatic Invasions in the Black, Caspian, and Mediterranean Seas (Nato Science Series)"). CC0 (metadata); book content not read. openlibrary.org
  10. Wikipedia, "Caspian Sea" (CC BY-SA 4.0), which cites: "Welcome to the Caspian Sea Level Project Site", Caspage.citg.tudelft.nl (original not read by us) en.wikipedia.org
  11. Wikipedia, "Caspian Sea" (CC BY-SA 4.0), which cites: A. G. Kostianoi and A. Kosarev, "The Caspian Sea Environment", Birkhäuser, 2005 (original not read by us) en.wikipedia.org
  12. Wikipedia, "Caspian Sea" (CC BY-SA 4.0), which cites: "The Caspian Sea Hits Historic Low - The Times Of Central Asia", 2025-07-23 (original not read by us) en.wikipedia.org
  13. Wikipedia, "Caspian Sea" (CC BY-SA 4.0), which cites: "Caviar pool drains dry as Caspian Sea slides towards catastrophe", The Nation, 2019-04-18 (we also read that source) en.wikipedia.org
  14. Wikipedia, "Caspian Sea" (CC BY-SA 4.0), which cites: Court, "Rapid decline of Caspian Sea level threatens ecosystem integrity, biodiversity protection, and human infrastructure", Communications Earth & Environment, 2025-04-10, p. 261; Court, "Rapid decline of Caspian Sea level threatens ecosystem integrity, biodiversity protection, and human infrastructure", Communications Earth & Environment, 2025-04-10, p. 261 (we also read that source) en.wikipedia.org
  15. Rebecca Court, "Rapid decline of Caspian Sea level threatens ecosystem integrity, biodiversity protection, and human infrastructure", Communications Earth & Environment (2025), doi:10.1038/s43247-025-02212-5. OpenAlex metadata CC0; paper not read. doi.org
  16. Wikipedia, "Caspian Sea" (CC BY-SA 4.0), which cites: Dumont, "The Caspian Lake: History, biota, structure, and function", Limnology and Oceanography, January 1998, p. 44–52 (we also read that source) en.wikipedia.org
  17. Henri Jean Dumont, "The Caspian Lake: History, biota, structure, and function", Limnology and Oceanography (1998), doi:10.4319/lo.1998.43.1.0044. OpenAlex metadata CC0; paper not read. doi.org

Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Caspian Sea (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.

Test yourself on TriviaCafe: Europe's longest river, the Volga, flows from hills northwest of Moscow about 2,300 miles, finally emptying… · What is the world's largest inland sea? · More geography trivia

Related entries

Sea, Europe, Asia

More in Rivers And Seas Of The World

Coral SeaDead SeaAmazon RiverAmu DaryaAmurAngaraBlue NileBrahmaputra RiverColorado RiverColumbia RiverCongo RiverDanube

Related in Rivers And Seas Of The World

Amu DaryaAmurBlack Sea

Links follow this subject's own source article.

Sources

Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.

Spotted an error? Know more?

Reader corrections go straight into our review queue. Suggest an edit · How this site is sourced

Comments

Loading…
Open in the interactive codex →