Black Sea

The Black Sea is a marginal sea that sits between Europe and Asia, positioned east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. Six nations—Bulgaria, Georgia, Romania, Russia, Turkey, and Ukraine—have coastlines along it. Its main water sources are the Danube, Dnieper, and Dniester Rivers, and while only six countries border the sea itself, its drainage basin extends into parts of 24 European countries. The sea covers 436,400 square kilometers, not counting the Sea of Azov, reaches a maximum depth of 2,212 meters, and holds a volume of 547,000 cubic kilometers. Most of the coastline rises steeply. To the south are the Pontic Mountains, to the east the Caucasus Mountains, and to the mid-north the Crimean Mountains, along with southwest-facing peninsulas. In the west, the coast features small floodplains below foothills like the Strandzha, Cape Emine (where the Balkan Mountains taper off), and the Dobruja Plateau farther north. The sea’s longest east–west stretch is about 1,175 kilometers. Key coastal cities, listed clockwise from the Bosporus, include the northern suburbs of Istanbul, Burgas, Varna, Constanța, Odesa, Yevpatoria, Sevastopol, Yalta, Kerch, Novorossiysk, Sochi, Poti, Batumi, Rize, Trabzon, Ordu, Samsun, and Zonguldak. The Black Sea has a positive water balance, losing a net 300 cubic kilometers annually through the Bosporus and Dardanelles into the Aegean Sea. Although the overall flow through these Turkish Straits is outward, water moves in both directions at once: denser, saltier Aegean water enters below the lighter, fresher water leaving the Black Sea. This creates a deep, permanent layer that never drains or mixes, making it anoxic. That oxygen-free layer preserves ancient shipwrecks found in the sea. The Black Sea ultimately drains into the Atlantic Ocean via the Turkish Straits, the Aegean Sea, the Mediterranean Sea, and the Strait of Gibraltar. The Bosporus links it to the small Sea of Marmara, which connects to the Aegean through the Dardanelles. To the north, the Kerch Strait joins it to the Sea of Azov. The sea’s water level has shifted greatly over geological time. When levels changed, the surrounding shelf and slopes sometimes became dry land. At certain critical levels, connections to other water bodies formed. The most active of these is the Turkish Straits, which now links the Black Sea to the global ocean. During periods when this link was absent, the Black Sea was an endorheic basin, independent of the world ocean system, much like the Caspian Sea today. Currently, its water level is relatively high, so it exchanges water with the Mediterranean. The Black Sea undersea river—a current of very salty water flowing through the Bosporus and along the seabed—was the first such feature ever discovered. Modern names for the sea in bordering countries are generally equivalents of “Black Sea.” These include, among others: Abkhaz (Амшын Еиқәа), Adyghe (Хы Шӏуцӏэ), Armenian (Սեւ ծով), Azerbaijani (Qara dəniz), Bulgarian (Черно море), Crimean Tatar (Qara deñiz), Gagauz (Kara deniz), Georgian (შავი ზღვა), Laz and Mingrelian (უჩა ზუღა), Persian (دریای سیاه), Romanian (Marea Neagră), Russian (Чёрное море), Turkish (Karadeniz), and Ukrainian (Чорне море). Such names have not been proven to predate the 13th century. In Greece, the historical name “Euxine Sea” (meaning “Hospitable Sea”) is still widely used, alongside “Mávri Thálassa” (“Black Sea”). Pontic Greeks also call it “Πόντος Εὔξεινος.” The Black Sea is one of four seas named in English after common color terms, alongside the Red Sea, the White Sea, and the Yellow Sea. The earliest known name for the Black Sea was the “Sea of Zalpa,” used by the Hattians and later the Hittites. The Hattic city of Zalpa was likely located at or near the mouth of the Marrassantiya River (modern Kızıl Irmak) on the Black Sea coast. The principal Greek name “Póntos Áxeinos” is generally thought to come from the Iranian word *axšaina- (“dark-colored”). Ancient Greek voyagers adapted it as “Á-xe(i)nos,” linking it to the Greek word “áxeinos” (“inhospitable”). The name “Πόντος Ἄξεινος” (“Inhospitable Sea”), first recorded in Pindar around 475 BC, was seen as bad luck and was euphemized to its opposite, “Εὔξεινος Πόντος” (“Hospitable Sea”), also first found in Pindar. This became the common Greek term, though in mythological contexts the original “Póntos Áxeinos” remained preferred.