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Sea of Azov

The shallowest sea in the world, whose basin possesses significant natural potential for biogas (methane) in bottom silt and is a global leader in fish resource density. Part of its coastline belongs to occupied Crimea, complicating the development of these energy riches by Ukraine.

Overview

The Sea of Azov is a unique natural phenomenon, the shallowest sea in the world: maximum depth is only 14 m, average — 7–8 m, and the sea floor is covered with a layer of silt 4–6 m thick. It is also the most deeply indented sea into the Eurasian continent. Thanks to its shallow waters, the sea warms up well in summer, contributing to the proliferation of plankton.

Geological origin and history. In prehistoric times, the Pontus (ancient Black Sea) was a gulf of the Arctic Ocean. When the Ocean retreated, large closed basins and lakes were formed — the Aral, Caspian, and Azov seas. The lowland in the lower reaches of the Don, Kuban, Molochna, Kalmius, Mius, and Yeya rivers became a sea back during the time of the first Hellenic explorations. Ancient Romans called the sea the "Maeotian Swamp", pointing to its even greater shallowing in antiquity.

Origin of the name. Ancient Greeks called it the Maeotian Lake; the name "Azov" originates from the Arabic al-zaward — "azure", sky blue. Ukrainian ancestors called it the Blue Sea (although marine vegetation gives the water a green hue). One of the Turkic names is Balik-deniz, i.e. Fish Sea. In ancient times it was also known as the Surozh Sea.

Salinity and ice. Water in the Azov is less saline — on average 11.5‰ (ten times more than fresh water, but three times less than ocean salinity). Due to low salinity, the sea freezes easily in winter, and in spring ice moves through the Kerch Strait (historically destroying structures, including the temporary Kerch Bridge).

Biogas and methane. Intensive biochemical processes take place in the bottom silt, more favorable than in the Black Sea, so a colossal amount of biogas consisting of methane is generated in a smaller area. Unlike the Black Sea depths, Azov biogas contains almost no hydrogen sulfide. Rising to the surface, methane spontaneously escapes into the atmosphere (damaging the ozone layer and enhancing global warming). Extracting and burning Azov methane causes less environmental harm than its free leakage — the resource is renewable. Scientists at Mariupol Technical University worked on extraction technology (communicating vessels principle: methane rises upward and fills the upper container). In coastal waters, the concentration of methane is several times higher than in the central part of the water area, so extraction is possible without floating platforms or seabed equipment.

Fauna. In terms of the quantity of marine fauna and flora, the Sea of Azov holds world leadership. The density of fish per unit area in Azov waters is: 6.5 times higher than in the Caspian Sea, 40 times higher than in the Black Sea, and 160 times higher than in the Mediterranean. Both marine and freshwater fish species inhabit these waters.

Energy potential. The Sea of Azov could yield approximately 100 billion m³ of biogas annually. For comparison: Ukraine currently consumes 32 billion m³ of natural gas (of which 18 billion is extracted domestically, and the rest is imported). The rf extracts 600–640 billion m³/year.

Key Details / Subtopics

  • Biogas / methane: renewable resource in bottom silt; extraction using communicating vessels principle; coastal concentration higher than central; absence of hydrogen sulfide unlike the Black Sea.
  • Geography and hydrology: shallowest sea in the world (average depth 7–8 m, max. 14 m); most deeply indented into the Eurasian continent; salinity ~11.5‰; silt 4–6 m; underwater bars (e.g. underwater ridge from the mouth of the Salhyr to the mouth of the Yeya River); etymology of names (Maeotian Swamp, Maeotian Lake, al-zaward/azure, Blue Sea, Balik-deniz/Fish Sea, Surozh Sea).
  • Fauna: world leadership in fish density; coexistence of marine and freshwater species; exceeding indicators of Caspian (×6.5), Black (×40), Mediterranean (×160).
  • Energy of Ukraine: potential ~100 billion m³/year of biogas versus consumption of 32 billion m³/year (domestic extraction — 18 billion m³); argument in favor of energy independence.
  • Coastline and occupation: one-third of the coast is Yedykuy (Lenine) District of Crimea (occupied by the rf); one-quarter is Krasnodar Krai; the remainder is Donetsk, Zaporizhzhia, and Kherson Oblasts. The issue of coastal ownership complicates resource development.
  • Energy of Two Seas. Part 2 — article by Valeriy Verkhovskyi (Krymska Svitlytsia, 2018, No. 21) on energy resources, biogas, fauna, and geography of the Sea of Azov.
  • Simply Put, This Is Also Crimea — article by Maksym Duboviaz (Krymska Svitlytsia, 2017, No. 24) on geological origin, shallow waters, salinity, and underwater relief of the Sea of Azov.
  • Arabat Spit — The Sea of Azov washes the Arabat Spit (Kherson Region).
  • Arabat Fortress — fortress on the isthmus between the Sea of Azov and Syvash.
  • Crimean Lighthouses — lighthouses provide navigation in the Black and Azov seas; Cape Fonar controls the entrance to the Sea of Azov.
  • Kherson and Taurida Governorates — Taurida Governorate covered the coastlines of the Black and Azov seas.
  • North Crimean Canal — the Azov Rice Canal branches off from the main canal on the territory of Crimea.
  • Crimean (Eastern) War of 1853–1856 in Kherson Region — shelling of settlements on the Azov coast (Henichesk, Arabat Spit).
  • Dolphins of the Black Sea — harbour porpoise (azovka), a cetacean species common to both the Black and Azov seas; marine fauna of the region.
  • Greeks in Crimea — Greeks resettled in 1778 to Pryazovia founded settlements here (Manhush, Urzuf, Yalta, etc.), becoming part of Ukrainian Pryazovia.
  • Mud Volcanoes of Crimea — Geological phenomenon on the Kerch Peninsula linked to the history of Ak-Monay Strait between the Azov and Black seas.