From the perspective of sailors, the sea was black due to severe storms in the winter, during which the water is so dark it looks black. The Black Sea is the world’s largest body of water with a meromictic basin. The deep waters do not mix with the upper layers of water that receive oxygen from the atmosphere. As a result, over 90% of the deeper Black Sea volume is anoxic water. The Black Sea is a saltwater sea, but it is of lesser salinity than the oceans. The salinity of the Black Sea’s surface waters averages between 17 and 18 parts per thousand, which is approximately half that of the oceans.
Where is the Black Sea located? Spread across an area of 436,400 km2, the Black is located in Eurasia, surrounded by Europe, Caucasus and Anatolia. The countries that share a border with the Black Sea include Romania, Turkey, Bulgaria, Ukraine, Russia, and Georgia.
Can aircraft carriers enter the Black Sea?
This, too, is impossible because of the Montreux Convention of 1936. Under that treaty, countries along the Black Sea get special naval privileges, and other countries are strictly limited in what ships may enter the sea (for example, no aircraft carriers or submarines), how many at a time, and for how long.
How many Russian warships are in the Black Sea? 25,000 (including marines) c. 39-41 surface warships (surface combatants, amphibious, mine warfare) plus support and auxiliaries 7 submarines (of which 2 in the Mediterranean as of March 2022)
The Black Sea was once a rich fishing ground, an
abundant source of fish for everyone from the Ancient
Greeks to the modern Soviet Union. Sturgeon and their
eggs were so plentiful in the estuaries of Black Sea rivers
that they were once the food of the poor.
Huge schools of anchovies migrated each year around the
northeastern shores, followed by bonito, mackerel, tuna, and
dolphins, which preyed on them and provided a wonderful
catch for Black Sea fishermen. Anchovies, known in Russia as
hamsa, moved in such vast numbers every spring through the
Kerch Strait into the Sea of Azov to spawn that fishermen only
had to stand in the water to fill their nets again and again.
The anchovies, in turn, depended on lush seagrass
meadows and vast kelp forests that grew on the seabed on
the northwestern shelves. Countless tiny animals sheltered
in the seagrass – amphipods, isopods, shrimp, molluscs, and
crabs, as well as the larvae of numerous large fish. Masses of
fish, including Black Sea turbot, whiting, rays, and, of course,
anchovies, feasted on this seabed banquet. Farther out from the
shore were rich oyster beds and carpets of mussels. Farther out
still grew vast forests of Phyllophora seaweed, the largest forests
of red algae in the world. The seaweed forests were not only
home to 170 species of animals, from sponges to crabs, but were
one of the main sources of oxygen in the oxygen-poor Black Sea,
cut off from the main ocean currents.
The Dead Sea
However, in the 1990s, the seagrass meadows and kelp forests,
as well as the oyster and mussel beds, all but vanished, victims
of disastrous pollution. Huge amounts of fertilizer and animal
manure drained into the Danube and other rivers from the
vast farms of Eastern Europe and Russia. As all these nutrients
washed out into the Black Sea, they triggered massive algal
blooms. So vast were these blooms that the sea stank of rotten
eggs. The stench was hydrogen sulphide gas given off by bacteria
multiplying to feed on all the decaying matter produced by
the algal bloom.
The masses of algae also cast the seabed into deep gloom,
blocking out up to 95 percent of the sunlight on which the
seagrass and kelp rely for energy. Almost all the kelp forests and
the seagrass meadows died within a few years. In the 1950s, there
were 10,000 sq. km (3,860 sq. miles) of kelp forests. By 1992,
there were just 50 sq. km (19.3 sq. miles), making a loss of
99.5 percent. With the kelp and seagrass went all the many
animals that relied on them – all the amphipods, the shrimp,
the crabs, and the fish. And as these animals went, so the
commercial fish, already reduced by overfishing, dwindled
almost to nothing, ruining the livelihoods of millions of Black
Sea fishermen. A huge area of the Black Sea became a dead zone.
The second wave
With the Black Sea ecosystem already weak, another, and even
more devastating, attack occurred as the invasive comb jellyfish
Mnemiopsis leidyi multiplied to an astonishing degree and
mopped up any survivors (see pages 224–225). It was not just
the wildlife and fishermen that suffered. Tourism plummeted,
too, put off by the smelly sea, and the fact that it was necessary
to shower after swimming to avoid the risk of disease. Many
people around the Black Sea stared poverty in the face. In 1998,
British born oceanographer Laurence Mee declared sadly,
‘The Black Sea is really facing an environmental catastrophe.
It is very unusual for scientists to use the word catastrophe. The
word is not used lightly.’
Mee orchestrated a campaign to get all the Black Sea countries
to come together in a last-ditch effort to save the Black Sea.
The Black Sea Environment Program, funded by the United
Nations, the European Union, and the World Bank, as well
as the Black Sea countries, was a pioneering example of
multinational cooperation. But in the end, the reason the
Black Sea is now showing real signs of recovery is down to
two remarkable strokes of luck.
The first piece of luck was the political upheaval of the early
1990s. As the communist regimes of countries along the Danube
and the Dnieper collapsed, so too did the farm programmes that
supplied farmers with fertilizers and created gigantic manureproducing
animal farms. Although it brought hardship to
farmers who could not afford to fertilize their crops, the nutrient
influx into the Black Sea plummeted. The dead zone shrank, and
seabed communities began to show small signs of recovery. By
2002, limited bivalve communities could be seen on the gravel
of the seabed. By 2006, seaweeds were beginning to grow well.
The second stroke of luck was the arrival of a second comb
jellyfish invader in 1997, Beroe ovata, which instead of preying
on fish fry and zooplankton ate the notorious comb jellyfish
M. leidyi. Anchovy numbers are now partially recovered, and
Black Sea turbot, bonito, and even mackerel are being caught
again. But it could all prove to be a false dawn. Scientists
warn that recovery will not continue unless fishing is severely
curtailed to avoid the knock-on effect through the food chain
that impairs the seabed communities. Moreover, the coast is
seeing a construction boom as tourism returns. And the massive
oil reserves of central Asia and the demand for oil in the West
have turned the Black Sea into a major conduit for oil supply. In
November 2007, a major oil spill in the Kerch Strait devastated
local bird life in what was described as the worst ecological
disaster in Russia since Chernobyl in 1986.