Black Sea (2 page)

Almost all discoveries have an element of successsful presentation about them. The undercurrent (Marsigli's
Corrente Sottano)
was known to those who worked in the waters of the Bosporus for a living, as Marsigli handsomely admitted. In his first account of his achievement, he wrote that 'my speculations had been stimulated not only by ideas formulated in my own inner cogitations but also by reports from many Turkish fishermen and above all by the urgings of Signor Cavalier Finch [Sir John Finch], Ambassador to the Porte of His Majesty the King of England and a great savant in the study of nature: to whom this notion was first disclosed by one of his ships' captains who was not able to reach any clear conclusions by experiment, perhaps for want of time . . .'

Marsigli's true glory is the way in which he followed through and consolidated his initial experiment. After the sounding, he took water samples at varying depths and was able to show that the water of the undercurrent was denser and more saline than the overcurrent running out of the Black Sea. He then constructed a demonstration apparatus: a vertically divided tank filled on one side with dyed sea-water of higher salt content and on the other with less saline water. Opening a hatch in the tank's partition, he allowed the two samples to mingle until the coloured sea-water had found its place as a visible layer at the bottom of the tank. And, without fully understanding what he had done, Marsigli had also discovered one of the basic facts of oceanography: that currents are generated not by gravity, like the flow of rivers, but by other forces which include the principles of fluid mechanics - in this case, a pressure gradient. The movement of heavier Mediterranean water into the Black Sea was impelling the lighter water in the opposite direction.

After Marsigli, other scientists, most of them Russians, began to explore the strange and stubborn nature of the Black Sea. Marsigli had shown that the Sea's water was less salty and dense than that of the Mediterranean, and he had explained a mystery: why its shore-level did not fall in spite of its outflow through the Bosporus. But it was left to others, much later, to uncover the basic fact about the Black Sea which makes it unlike all other seas: that almost all of it is dead.

On the atlas, the Black Sea appears as a kidney-shaped pond, connected to the outer oceans by the thread-like channel of the Bosporus and the Dardanelles. And yet it is a sea, not a fresh-water lake: a salt-water mass some
630
miles across from east to west and
330
miles from north to south - except at its 'waist', where the projecting peninsula of Crimea reduces the north-south distance between the Crimean shore and Turkey to only
144
miles. The Black Sea is deep, reaching down to more than
2200
metres in places. But there is a large, shallow shelf in its north-western corner, off the stretch of coast which reaches round from the Danube delta in Romania in the west to Crimea in the north. This shelf, less than a hundred metres deep, has been the breeding-ground for many of the Black Sea's fish species.

As one travels clockwise round the Sea from the Bosporus, the Bulgarian and Romanian shores are seen to be low-lying, like most of the Ukrainian coastline. Then come the towering sea-cliffs of the Crimean mountains. The eastern and southern coasts (Abkhazia, Georgia and Turkey) are mostly mountainous, sometimes fringed with a narrow coastal plain and sometimes — as in north-eastern Turkey — plunging steeply down to the Black Sea in forested ridges and gorges.

But it is the rivers which dominate the Black Sea. Only three major rivers — Rhone, Nile and Po — run into the far bigger Mediterranean. But the Black Sea receives five: the Kuban, the Don, the Dnieper, the Dniester and, above all, the Danube whose drainage basin extends across the whole of eastern and central Europe and almost to the borders of France. The Danube alone carries
203
cubic kilometres of fresh water into the Black Sea every year, more than the entire flow of river water into the North Sea.

It is these rivers, source of so much life, which over tens of thousands of years extinguished life in the Black Sea depths. The inrush of organic matter from the rivers was too much for the bacteria in sea-water which would normally decompose it. They feed by oxidising their nutrients, using the dissolved oxygen normally present in sea-water. But when the organic inflow is so great that the supply of dissolved oxygen is used up, then the bacteria turn to another biochemical process: they strip the oxygen from the sulphate ions which are a component of sea-water, creating in this process a residual gas: hydrogen sulphide, or H
₂
S.

This is one of the deadliest substances in the natural world. A full breath of it is usually enough to kill a human being. Oil workers know and dread it; they watch for its rotten-eggs reek and at the first whiff they run. They are right to do so. Hydrogen sulphide almost instantly destroys the sense of smell, so that after the first sniff it is impossible to tell whether one is inhaling more.

The Black Sea is the world's biggest single reservoir of hydrogen sulphide. Below a fluctuating depth of between
150
and
200
metres, there is no life. The water is anoxic, without dissolved oxygen, and impregnated with H
₂
S; because much of the Black Sea is deep, this means that some
90
per cent of the Sea's volume is sterile. It is not the only place in the oceans where H
₂
S has accumulated. There are anoxic areas on the floor of the Baltic Sea, and under some Norwegian fjords where water circulation is slight. Off the Peruvian coast, hydrogen sulphide is sometimes brought welling up from the depths to the surface in the periodic catastrophes known as 'el Nino', where it kills the entire ecosystem, destroying the coastal fisheries and reacting with paint on ships' bottoms to turn them black (the 'Callao Painter' effect). But the Black Sea deeps remain the largest mass of lifeless water in the world.

And yet, until the last hundred years, the Black Sea has seemed to human beings a place of almost monstrous abundance. The poisonous darkness lay far below, unknown to anyone. Above the hundred-fathom line, the 'haloclyne' or 'oxyclyne' which marks the upper limit of anoxia, the Sea boiled with life. Salmon and huge sturgeon — the beluga can reach the length and weight of a small whale — crowded up the big rivers to spawn (caviar was so plentiful that in fourteenth-century Byzantium it was the food of the poor).
¹
Along the shores and on the shallow north-western shelf of the Black Sea, there lived spiny turbot, sprat, goby, ray, grey mullet and whiting, most of them feeding off underwater prairies of
Zostera
sea-grass.

On the other side of the Crimean peninsula, in the far northeastern corner of the Black Sea, is the Sea of Azov, resembling a miniature version of the Black Sea itself with its narrow channel -the Kerch Straits - connecting it to the larger ocean. This small sea, shallow and landlocked, used to be the home of more than a hundred breeds of fish in the
130
miles between the Kerch Straits and the marshy delta of the river Don. At every spate, the Don delta would flood up over miles of reeds and brackish mud, providing spawning-grounds for fat river fish which could be caught by the cart-load. Millions of marine fish on their migrations to breeding areas pushed through the Bosporus at Istanbul, or through the Kerch Straits into the Sea of Azov. Catching them required little more effort than sticking a hand-net out of a sea-side window, and Strabo wrote that in the Golden Horn, the creek of the Bosporus which runs up under the walls of Istanbul, bonito could be pulled from the water with bare hands.

Out in the open waters, among the schools of dolphin and porpoise, two fish species performed a slow, gyratory migration around the Black Sea, their progress almost as punctual as a shipping schedule. One was the bonito
(palamud),
a member of the mackerel family so important to food and trade that its image appears on some Byzantine coins. The other was the
hamsi,
or Black Sea anchovy.

To this day, the shrunken remnant of the anchovy hordes spawn off the Bay of Odessa in July and most of August, setting off on their anti-clockwise journey round the Sea between the last week of August and the first days of September. Travelling about twelve miles a day, in groups whose biomass even now weighs up to
20,000
tons each, they pass the delta of the Danube, skirt the shores of Romania and Bulgaria, and then turn east along the coast of Anatolian Turkey. By early November, the shoals are midway between Istanbul and Sinop, several hundred miles to the east. The fish have grown heavier and are travelling more slowly in tighter groups as they enter the main fishing areas off Trabzon (Trebizond). Finally, in the New Year, the anchovies reach the south-eastern corner of the Black Sea, somewhere off Batumi, and then divide: some heading north along the Georgian and Abkhazian coasts and round to their point of departure, others returning to Sinop and then cutting straight across the central Black Sea to the Bay of Odessa. One estimate of the
hamsi
biomass, done before genocidal overfishing collapsed the species in the
1980s,
suggested that something approaching a million tons of anchovies swam in this circular pilgrimage every year.

Fish brought the Black Sea into history. There were, of course, other factors too: other prodigious sources of food and wealth. The south Russian plains for example, the so-called Pontic Steppe, formed a level expanse of prairie stretching for almost
800
miles from the Volga River to the foothills of the Carpathian Mountains in the west, a band of open country some
200
miles deep between the sea-coast and the forest country to the north. The grasslands of the Pontic Steppe could feed the horses and cattle of a whole nomad nation; later, its best soil was ploughed up and grew the finest wheat in the world before the cultivation of North America. In the mountains of the Caucasus, whose snowy summits were visible from far out at sea, there were both timber and gold. Across the river deltas wandered flocks of edible birds which darkened the sky with their migrations. But in all that apparently infinite plenty of natural life, the fish mattered most.

The voyage of the
Argo
is a Bronze Age legend. When Jason crossed the Black Sea, ran his boat up the river Phasis in Colchis (part of modern Georgia) and tied her fast to the trees overhanging the bank, he was after magical treasure - the Golden Fleece of Colchis. But gold is for heroes. All along the Black Sea coasts, inshore dredgers bring up from the sea-bed big stones pierced with a hole: the anchors of Mycenaean ships. These carried the real Bronze Age venturers. They brought with them from the Aegean luxurious trade goods like ornamental pottery and decorated rapiers, but they were looking for food to bring home, and what they took away seems to have been mostly fish: sun-dried, or cured with salt from the Dnieper and Danube estuaries. When the Mycenaean kingdoms passed away and were replaced by small, hungry city-states perched on Greek and Ionian headlands, the ships returned to the Black Sea on the same errand, which became steadily more desperate as the city-states grew more populous and their small arable hinterlands grew less fertile through over-cultivation. By the seventh century BC, the Ionian Greeks were establishing coastal colonies all round the Black Sea, settling into communities whose first business was the curing, packing and exporting of fish.

Satisfying this need, a very simple one, led unexpectedly into one of the formative moments of human history. The significance lay not just in the meeting of settled, literate people with pastoral nomads. That had happened before, and would happen again. It was important because the literate people brooded on this meeting, and constructed from it - the first 'colonial' encounter in European experience — a series of questioning discourses which still remain with us.

One discourse concerns 'civilisation' and 'barbarism'. A second is about cultural identity, and about where its distinctions and limits should be drawn. A third is a deep self-criticism which imagines that technical and social sophistication entails not only gain but loss — a departure of conscious and rational behaviour from what is 'natural' and spontaneous.