Academician L.A. Zenkevich

Dreams of controlling the fantastic riches of the Ocean has lived in mind of Man for many centuries. The path to those riches was blocked by the violent temper of the Ocean, the absence of scientific knowledge and reliable engineering. Beginning in the mid-20^th century, the situation sharply changed. The necessity for raw material forced Man to look toward the Ocean for help. An intensive search effort by scientists and engineers resulted in increased knowledge and opened the door to a promising future by utilising the treasures of the Ocean. A commonplace feature of the Ocean landscape has become drilling and petroleum production platforms not only near the coasts, but also in the open areas on the outer continental shelves.

Exploitation of coastal and marine placer deposits is also underway. Several kinds of minerals are mined from these deposits which, in some cases, is easier than onshore mining. These processes are the results of long-term engineering studies and the creation of techniques for the recovery of raw materials, now extending into deeper waters.

Further development of prospecting and extraction methods, especially in the open Ocean, depends on the International Law of the Sea, since all types of Ocean activity are closely interconnected.

As continental mineral deposits gradually become exhausted, the methods for extraction become complicated, and the cost of their recovery dramatically increases. At the same time, from near the coasts down to great depths, extensive regions of the World Ocean hold enormous reserves of mineral and chemical resources necessary for well-being of Mankind and its industrial activities. Therefore, interest in the search and development of richest marine deposits steadily grows by scientists, engineers and economic specialists.

The Oceans contain all known minerals found on the Earth, but most are in a dissolved form, in a suspension or in bottom deposits. Reserves of many kinds of marine raw minerals are frequently extensions of onshore resources. The World Ocean hides about 65% of the potential oil and gas reserves of the Earth - 35% are on the shelf and 30% extend to the bottom of the continental slope and in deep-water basins.

As a storehouse of raw materials, the Ocean can be divided into 3 sections: lower - deep within the sea floor; middle - the surface of the sea floor with uncompacted, mainly recently deposited sediments: and upper - within the sea water.

In working situations, marine mineral reserves are classified as liquid, gaseous and soluble. Their extraction is made possible with the help of drill holes (petroleum, gas, sulphur and other accompanying minerals); hard surface dredging, hydraulic or similar engineering methods (metalliferous deposits, silts, pavements, etc.) and solid, buried deposits which are extracted from underwater mines (coal, iron ore, tin, etc.).

Using physical and chemical processes, various chemical elements and compounds, such as sodium chloride (cooking salts), magnesium, magnesium chloride, bromine, potassium compounds, iodine, titanium, etc. are extracted from sea water. Attempts are being made to recover gold, uranium and lithium. Extraction of the majority of chemical resources from sea water is conducted in natural and special pools by evaporating the sea water as a result of solar heating.

Since it is a naturally-occurring material, sea water can be used immediately, without processing, in industry and agriculture. On sea coasts, especially in arid regions, sea water is turned into fresh water at special processing plants, greatly easing the natural deficit.

Intensive exploration activities and maintenance of natural marine hydrocarbon deposits (oil and gas) are presently being conducted. At the end of the 1980s, the total annual extraction of petroleum from undersea deposits was about 13 billion tons. Industrial development of oil and gas has been implemented on the shelves off 40 countries. It is expected that, by the year 2000, fully half of all oil and gas produced World-wide will come from the depths of the World Ocean.

Oil and gas were formed in ancient marine basins under favourable geological and thermodynamic conditions. The Ocean environment provides a favourable environment for organic life, and after these animals die, it provides a fast burial place for them on the bottom, where oxidation is non-existent. The bodies of these micro-organisms contain various substances, among them, organic hydrocarbons, which are similar to petroleum. These are called scattered or micro-petroleum.

Gradually, layers of micro-organism deposits form on the bottom under increasing pressure which causes a rise in temperature. Under these conditions, the properties of proto-petroleum change, and the deposited contents thicken. The newly-formed petroleum migrates to structural traps, most often in natural, convex folds (anticlines) in the sediment layers. The petroleum accumulates near the tops of the anticlines, forming oil and gas pools.

People have known about marine petroleum deposits for a long time. In 1824, cofferdams were constructed near the shore of the Caspian Sea in the region near the city of Baku (Azerbaijan), isolating the sea from the shore, and petroleum was scooped from the surface sediment layers.

Near the Japanese city of Izumosaki, an artificial, alluvial island was constructed for a petroleum derrick in 1870. In 1891, the drilling of inclined holes from the shore into the sea began on the coast of California. The first oil drilling from a barge began on Lake Maracaibo in Venezuela in 1933. Petroleum derricks were constructed over drilling holes in the Gulf of Mexico, connected to the shore by wooden bridges, thus starting commercial exploitation of underwater oil deposits. Commercial development of underwater petroleum deposits was begun in 1938 off the coast of the state of Louisiana (USA).

Geologists and geophysicists use special acoustic devices to penetrate the sea floor and reveal structural traps. However the quality and quantity of petroleum or gas can be learned only by drilling into the sediments.

Continental and insular shelves of the World Ocean have become the primary regions for petroleum and natural gas exploration and drilling. Hundreds of reservoirs of "black gold" are already developed in these areas. There are over 3,000 steel platforms extracting of petroleum and natural gas, and tens of thousands of holes have been drilled into these reservoirs.

Wells drilled from the shore, artificial islands or on pilings into the shallow, near-shore zone are joined with the shore by special viaducts. These are widespread in the Gulf of Mexico, in Venezuela and in the Caspian Sea. Oil is primarily transported from the wells to storage facilities by pipelines, but also by barges and other methods.

Permanently-placed marine petroleum platforms can be constructed on the sea floor in depths of up to 200 m. Development of deposits in deeper water can be done by using semi-submersible platforms, kept in-place by special, deep-water anchors. Production activities in depths of up to 1,000 m are conducted not only from floating and stationary platforms, but also from underwater systems. The depths of exploratory drill sites reached 2,500 meters by 1985. Drill-ships equipped with dynamic positioning systems can drill wells in depths of up to 5 km.

Volume of World oil extraction from the Ocean floor (in million tons)

Usually deposits of petroleum and gas exist in groups, forming so-called zones of oil and gas accumulation. Some zones are located over large areas and connected to large oil and gas basins in the Earth’s crust. Those, together, make up a province.

The geography of marine extraction of petroleum rapidly enlarges and changes. In 1970, 34% of oil extraction occurred in Venezuela, 30% in the USA and 26% in the Persian Gulf states. By 1980, the Persian Gulf states were the number-one producer.

The oil and gas-bearing province of the Persian Gulf is one of the richest in the world. Together with the adjacent land of the Arabian Peninsula, the region holds more than half of the World reserves of petroleum. There are 42 reservoirs of petroleum in the Persian Gulf, which have an unusually high number of producing wells.

By comparison, the daily average production of wells is (in tons): in the USA - 2.5; in Canada - 16.3; in Saudi Arabia - 1,509; in Iraq - 1,960; in Iran - 2,300.

The large annual extraction of petroleum from a small number of wells in the Persian Gulf, in comparison with other regions, provides a much more cost-effective and therefore lower price on the World marketplace.

Great Britain and Norway have become the primary oil-producing countries of Western Europe. Exploration and prospecting activity in the North Sea have begun in 1959. In 1964 there was a partition of the sea floor between the coastal nations surrounding the North Sea. Commercial deposits of natural gas were detected in 1965 in the coastal waters of the Netherlands and near the east coast of Great Britain. By the end of the 1960s, commercial production of petroleum from the central North Sea was in operation. The North Sea oil and gas-bearing province covers 660,000 km². The largest petroleum deposit in this province is Ekofisk (Norway). Exploitable reserves are estimated to be 1 billion tons. Presently, the daily average production from the wells is up to 500 tons.

The oldest producing oil and gas-bearing offshore province is in the Gulf of Mexico. It was here that the exploration and prospecting techniques for the extraction of petroleum and natural gas were developed Marine geophysical researchers have efficiently penetrated the deep horizons of sedimentary cover, and determined that the tops and flanks of so-called “salt” domes were oil-bearing places. After extensive research by experts, it has been determined that this unique area in the World Ocean is the only such place presently known where it is sensible to drill oil and gas wells to depths of more than 7.5 km.

Within the limits of the Texas and Louisiana coasts, a bay exists that contains more than 100 deposits with estimated recoverable petroleum reserves of 7.7 billion tons, and 4.3 trillion m³ of natural gas. These deposits are now in production. Rich deposits of petroleum and gas are found along south-west and southern coasts in the Gulf of Mexico Gulf and in the territorial waters of Mexico.

The Caspian Sea is the World’s largest internal sea. Its sea floor contains a huge reserve of petroleum. The South-Caspian oil and gas bearing province was formed in relatively recent geological time. The deposits of petroleum and gas are located mainly in the western part. The main marine oil-production/processing facility of the of the Caspian Sea Petroleum Refinery is located here. Petroleum derricks on fixed pilings are located in depths of up to 60 - 80 m. Utilising modern, semi-submersible drilling rigs, drilling is accomplished in depths of up to 200 m.

One of the largest estimated reserves for oil extraction is on the coast of West Africa. More than 160 marine deposits of petroleum and gas, among them the giant Amerada petroleum field with estimated reserves of 1 billion tons, are in production.

Rich marine petroleum and natural gas deposits are also located near the shores of Indonesia and Indochina, and in the shelf zone off northern Australia.

At the end of 1960s, active exploration began for marine deposits of petroleum and natural gas in coastal regions of the Arctic Ocean. The location of a unique gas and oil deposit was discovered in the Beaufort Sea at Prudhoe Bay, on the northern coast of Alaska, and in the Mackenzie River (northern Canada) delta, 18 petroleum, natural gas and condensed-gas deposits have been located. Petroleum and natural gas are being searched for on the shelves of the Canadian Arctic archipelago, north-east Greenland and the islands of the Spitsbergen archipelago. Also in the Arctic, petroleum is extracted on the southern shelf of the Barents Sea. Artificial ice islands are frequently built for drilling wells in the Arctic region.

There is a rapidly-developing marine oil and gas industry in the South American countries of Argentina and Brazil.

The exploitation of marine deposits has resulted in the solution of many technical problems. It promotes development and perfection of marine drilling engineering, a growth of the shipbuilding and machinery construction industry in a number of coastal nations.

 Solid mineral wealth extracted from the Ocean, in proportion to the difficulty of extraction are produced in considerably smaller quantities than petroleum and natural gas. However the exhaustion of similar reserves on land have stimulated exploration and an increase of mining them in the Ocean.

The deposits of the solid mineral wealth in the World Ocean can be subdivided into the following categories: radical, formed in-place, and placer. The latter is a concentrated deposit where a deposit forms on an underwater coastal slope, with a steady accumulation near the shore (beach, spit, dune), in deltas of rivers, etc. Radical, on the other hand, can be divided into buried, which are recovered from within the bottom, and surface, located at the sea floor as pavements, silts, etc.

The mining of radical deposits of minerals is usually conducted through inclined shafts, beginning on the coast, or on natural or artificial islands. Horizontal mine shaft tunnels are dug from a shore at distances of up to 10-12 km, in depths of up to 120 m. By this method, it is possible to mine coal (e.g., up to 40% of the total volume mined by Japan), iron ore (the deposit on Newfoundland (Canada) annually extracts more than 3 million tons) and in the Aegean Sea in Turkey, mercury ores are mined.

Radical tin deposits are extracted from the offshore region of the Cornwall peninsula (Great Britain). The marine waters here hide ore veins of tin, tungsten, copper and other metals. Copper and nickel are extracted in small quantities from underwater mines in Hudson Bay (Canada).

In the sedimentary layers on a shelf that is usually associated with salt domes, sulphur is found in deposits tens of meters thick. Potential sulphur deposits are estimated to be from tens to hundreds of millions of tons. The extraction of sulphur from wells at depths on the order of 15m in the Gulf of Mexico is accomplished from platforms on artificial islands.

Coastal-marine deposits are veritable storehouses of valuable minerals and metals. Their formation occurs as follows: weathering of metalliferous ores on land results in transport by rivers draining into the Ocean. In the coastal zone, currents, waves and tides sort the deposited material so that the metallic (heavier) particles are dropped and sorted according to size. The tidal changes, surf activity and geology of the adjacent land determines the structure of placer deposits. The conditions for deposition of the loose materials are determined by the type of materials, and in most cases are found along the shore at shallow depths with wide coverage.

At the end of the 19th and the beginning of the 20th centuries, mining of placer gold deposits was begun, followed by ilmenite, rutile, zircon and monazite on the coasts of Australia (1870), Brazil (1884) and India (1909). The extraction of tin from marine deposits started in Indonesia in1962, and diamond mining began on the shelf of Southwest Africa (Zambia) about the same time. In the USSR, work on mining coastal-marine deposits was initiated in 1966 on the shelf of the eastern Baltic Sea coast, where titanium-zircon concentrates were extracted.

An important feature of placer deposits is their ability to be restored as a result of the sea transporting new materials to the site, as opposed to land mining, where materials are only removed.

World production of minerals from coastal-marine placers, while presently insignificant in volume, produced certain raw materials of high value. Some coastal-marine placers contain valuable metals, rare earths and radioactive elements in great amounts. Ilmenite and rutile, for example, are rich in titanium, which is widely used in special metallurgy, electric welding and other areas of engineering. Zircon - the main source of zirconium - also contains hafnium, yttrium, tantalum and niobium. Monazite is raw material for cerium and thorium, used in nuclear engineering and energy production.

Coastal-marine placers provide 100% of the zirconium and rutile, 80% of the ilmenite and more than 40% of the cassiterite used in modern industry.

Gold and platinum are usually found in placers of other minerals, but sometimes, they also form independent deposits. For example, on an Alaskan peninsula near the city of Nome, an industrial-grade deposit with a gold content of up to 15 g/m³ has been found, and in Goodnews Bay, platinum deposits with up to 10 g/m³ are mined.

Basic deposits of diamond sands are found on the continental shelf off Southwest Africa. They provide 5% of the volume of the World market in precious stones.

A peculiar kind of mineral raw material is amber (fossil plant resin), used in jewellery production and in the chemical and pharmaceutical industries. Amber is found on the Baltic North and Barents Seas.

Sand, clay, gravel and coquina are extracted in aggregate form from the shelves for manufacture of building materials. Great Britain, Iceland, Russia, USA and a number of other countries produce lime, cement and fodder flour from extracted coquina.

Depending on geological and meteorological conditions, placer deposits are exploited by various means, including the use of equipment for mining and transporting of raw material. This equipment includes underwater bulldozers, earth-moving machines, dredges and a lot of scooping, hydraulic and grab drags. The raw materials are delivered to processing and storage facilities with the help of pipelines, vessels, barges, etc.

Among the minerals found on the World Ocean floor, phosphorites hold a special place. They are formed as a result of biochemical processes occurring during precipitation of dissolved phosphorus compounds which had been dissolved in sea water. Phosphorite deposits are found on the sea floor in the form of nodules about the size of large cobbles to phosphate sands and phosphate clays or in layered beds. They are widely distributed near the outer edges of the continental shelf and on flat tops of guyots. The reserves of phosphorites on oceanic bottom are estimated to be in hundreds of billions of tons. If 10% of the reserves was used today, Mankind will still have raw phosphates to use for a thousand years or more.

A sizeable area of the Ocean bed contains ferro (iron)-manganese nodules. The Pacific Ocean has a great abundance of them, since these nodules cover almost the entire deep-water sea surface. Nodules are naturally round and/or lens-shaped concretions containing a high concentration of mineral substances. The chemical composition of nodules is not consistent. They can contain up to 30 various elements, but manganese and iron predominate. The sizes of nodules vary from less than 1 cm up to 1.5-2.0 m in diameter.

Variety and average composition of nodules by main components (by weight %)

Nodules were found in the Ocean for the first time during the research expedition on the vessel, HMS "Challenger" (1872-1876). For a long time, they were considered “exotic deposits.” Only during the last half of the 20th century, when it was proved that mining them from the sea floor is technically possible and can be profitable, has interest in nodules increased to the point where exploitation can become a very large industry. The reserves of iron-manganese nodules are enormous. The quantities of the various metals and minerals contained in them, many times exceeds their reserves on land.

Metalliferous deposits are sea-bottom sediments containing high concentrations of valuable metals, such as, iron, manganese and zinc. They were first discovered the 1960s. Metalliferous deposits are formed as a result of the interaction of thermal waters raised from the depths of the Earth with water the environment of the Ocean and suspended matter at and near the bottom. As an outcome of these complex physical-chemical processes, a high concentration of metals is formed. Metalliferous deposits have been detected in regions of underwater volcanoes in the mid-oceanic ridge system.

The study of metalliferous deposits is in a developmental stage. The attention of geologists and engineers has been drawn to deposits in the Red Sea, most of which are enriched with metals. Their iron content is about 26 %. Extraction may be possible using special suction devices, which are designed to create an erosion effect on the deposits. Using a system of pipes they will be “vacuumed” from the sea floor onto a cargo/recovery ship.

Ocean bottom accumulations of polymetallic sulphide ores have been found on the slopes of geyser-like structures called “black smokers” over the last several years. The ore differs structurally from iron-manganese nodules. Sulphide ore has a lot of zinc (in some cases up to 50-60%), a high copper content, and varying amounts of lead, antimony, arsenic etc. The interest in sulphides as a new source of metals is very great, however it is still necessary to answer many questions: how to extract these ores, how large are their reserves, what is the quality and quantity and whether the ore body is economically exploitable. Studies of the natural deposits in the Ocean with the use of new technology has only just begun, and the practical removal of sulphide ores remains a business of future.

By carrying out deep-water drilling and seismo-acoustic sounding of the sea bottom, scientists have detected accumulations of natural gas in a unusual state. Molecules of gas, by incorporating with water, form hydrates, which outwardly appear to have the physical properties of ice. The process has been going on in the bottoms of the seas and Oceans for several million years. Unique reserves of frozen methane gas have been noticed on the surface, and from depths of several centimetres down to 200-300 m below the sea bottom. Scientists think that the richest deposits may be on the continental slopes. Deposits of methane (gas) hydrates may exceed those of petroleum and natural gas by a hundred times or more. It may be possible to develop gas hydrate deposits by installing special equipment on the sea floor, which is joined with a receiving vessel. Extraction of gas hydrates will most likely have a very low impact on Nature, since the crystalline gasses are edible by a number of marine micro-organisms.

Organic and inorganic elements and compounds which are dissolved in the seas and oceans, are the chemical resources of the Ocean.

The main quantities of dissolved elements are chlorine, sodium and magnesium. There are also insignificant concentrations of silver, zinc, copper, mercury, uranium, gold etc. Waters of the World Ocean are figuratively called, "liquid polymetallic ore."

Reserves of chemical resources in the Ocean are practically unlimited, since the constant chemical composition of sea water is based upon continual deposition/solution from the environment. Only a small fraction of the large variety of chemical riches of the Oceans and seas is presently extracted, because the technology has not yet been developed to accomplish this in an economical manner. Constantly improving mining, and recovery processes will make it possible in the future to extract chemical resources from the sea.

Marine water is also a reserve of raw material for the production of fertilisers, salts, acids, alkalis, various metals and a number of chemical products.

In ancient times, people learned to use cooking salt. In countries with a hot and dry climate, salts are extracted by evaporation in special pools (or lagoons) under natural conditions, using energy of the sun and wind. At present, the same methods are used for obtaining the salts. There is also the method whereby salt is deposited when sea water freezes, however this process is not widely used.

The best cooking salt contains not less than 96% NaCl (sodium chloride), and is used mainly for food preparation and seasoning. In industry, lower quality salt is used. Cooking salt is necessary for manufacture of soda, salt acid, plaster, glass, soup, papers, clearing of fats, smelting of metals, etc.

One-third of the World’s supply of salts comes from the seas and Oceans.

1.Chlorine 2.Sodium 3.Magnesium 4.Sulphur 5.Calcium 6.Potassium 7.Bromine 8.Strontium 9.Boron 10.Silicon 11.Fluorine 12.Nitrogen 13.Lithium 14.Rubidium 15.Phosphorus 16.Iodine 17.Barium 18.Zinc 19.Iron 20.Aluminium 21.Molybdenum 22.Tin 23.Copper 24.Arsenic 25.Uranium 26.Nickel 27.Vanadium 28.Manganese 29.Titanium 30.Antimony 31.Cobalt 32.Caesium 33.Cerium 34.Yttrium 35.Silver 36.Cadmium 37.Tungsten 38.Chromium 39.Thorium 40.Lead 41.Mercury 42.Bismuth 43.Gold

Simple magnesium and its compounds are widely used in the construction of rockets, aircraft and spacecraft. Textiles, building materials, paper, rubber, pharmaceuticals and agriculture are also customers. The Ocean provides more than 40% of all magnesium produced World-wide.

Presently, only England and the USA have more than 20 plants producing a majority of magnesium from sea water, a majority of which is consumed within these countries.

Potassium salts represent the bases for various agricultural fertilisers. Usually they are received as a by-product of sodium chloride production. Potassium salts are used for refining, cleaning and dyeing fabrics, in the production of explosives and other items. The extraction of potassium from marine water was begun during the First World War in Japan and China.

Sea water and the precipitation of salts of dried up seas are basic sources of bromine. Bromine is practically unobtainable from land minerals. Although bromine concentration in sea water is rather minor (0.008%), it exceeds by 8 times the contents of an equal volume of land minerals. Current World-wide extraction of bromine is about 10,000 tons/year. Pharmacists have long used bromine for the preparation of medicines. Interest in bromine increased after the discovery of two-bromide ethylene, a compound permitting to prepare fuels that do not explode in internal combustion engines. Bromine is also used in the production of dyes, photographic and film-materials, fire extinguishers, etc.

The production of iodine from sea marine water is based on extracting it from the water with the help of activated charcoal, and also by processing of laminaria seaweed.

High hopes are laid to waters of the Ocean as a source of uranium, radium, gold, lithium, caesium and other trace-elements. Great obstacles lie in the path of extraction of these elements because the quantities are too small to efficiently extract them, thereby making technological methods very complex, and the final yield extremely expensive. Prospective methods for their extraction by using synthetic, ion-exchanging resins are being studied, due to the tendency of some materials toward selective absorption of a required group of elements. These methods have been developed to some degree and Japan was the first to build a facility for obtaining uranium from marine waters.

Use of biological methods to extract rare elements is based on the fact that that some marine plants and animals are capable of filtering them from water and storing these elements in their bodies. For example, in the bodies of marine crayfish (spiny lobsters) cobalt and radioactive plutonium²³⁹ have been found; holothurians and ascidians have vanadium in their bodies; the cellular tissue of oysters stores copper; there is gold in the bodies of jellyfish; and zinc, tin and lead have been noted. In some seaweed and the concentration of iron is 100,000 times greater than in marine water.

Waters of the seas and Oceans are the main storehouses of hydrogen and its heavy isotopes deuterium and tritium), and the latter are included in the structure of heavy water. The mass of the heavy water of the Ocean is estimated at 274,000 billion tons. The use of nuclear energy created by a reaction between deuterium and tritium opens a practically inexhaustible source of convenient and cheap energy to Mankind. Heavy water is presently used to decelerate reactions in nuclear reactors. The largest production facility for heavy water in the World (77% of the production from it goes to countries of Western nations) is in Canada.

Hydrogen is a natural fuel which is extractable from sea water by electrolysis. It is used in many industries and in transportation. World-wide, more than 20 million tons of hydrogen are produced annually.

The salty waters of the World Ocean are used not only for manufacturing of chemicals, but also as a raw material for obtaining fresh water. Rapidly developing industry and agriculture, and growth of the population of the Earth, requires an increasing quantity of fresh water. The available natural resources of fresh water are extremely nonuniformly distributed on our planet. About 2 billion people are without the necessary quantities and quality of it. The shortage of the fresh water is so acute, the UN declared 1981-1990 as the "Decade of Potable Water". The heavy activities of desalination of salt waters of the ocean should play a significant role in slaking of the "eternal thirst."

Distillation of marine water has been a problem for a long time in connection with the fresh water supply of vessels on extended voyages. Obtaining fresh water by distillation has been used by seafarers from ancient times. The primary locations, the number of distilling installations and the output amounts of fresh water has for a long time belonged (and still belongs) to the marine fleet.

Creation of industrial distilling installations on land began in the end of the 19^th - beginning of the 20^th centuries. From the middle of the 20th century, distilled water began to be made in industrial quantities. At the present time, about 30 different methods are known to desalinate sea water. All of the methods of transforming salt water to fresh require large expenditures of energy. For example, desalination by distillation requires the production of 13-14 kW/h / ton. The distillation method is considered as very simple and reliable. The use of it becomes economically expedient where high levels of salts are present in marine water.

Alongside with perfecting distillation methods, other methods have been developed for obtaining fresh water: natural and artificial freezing; chemical processes such as ion exchange; extracting processes using a diaphragm, hyperfiltration (electrodialysis); and biological methods.

A common fault of all methods of desalination is in the problem of removing residual brine. Brine is the residue of fresh water production, and at significant levels of desalination it needs to be removed from the ground areas thereby requiring construction of facilities for warehousing. Brine residue storage can be on land or it can be removed to the sea, but this procedure can damage local ecological systems. In the long term, brines should be subjected to further processing and removal of useful elements.

In the 1970s, there were only 800 large desalinisation plants in the world, with a total output of 1.25 million m³/day. By 1985, the output volume of desalinated water increased to 10 million m³/day. Over the last 20 years, the price of distilled water has decreased 100-fold. Presently, the most efficient installations, in Kuwait and Las Palmas (Canary islands) can produce a cubic meter of fresh water for 10 cents. The end of high prices for fresh water and the significant progress in the field of sea water desalination methods make distilled water comparable to natural, fresh water.

There is one more way of obtaining of fresh water, which on can produce better tasting qualities, and which greatly exceeds the amount of water from desalinating installations: from glaciers.

Scientists have suggested various ways of transporting icebergs from the Antarctic continent and Greenland. For the economic reasons, transporting of Antarctic icebergs is most preferable for the nearest southern regions of America, Africa and Australia. Transportation of Antarctic icebergs to the Northern Hemisphere, in particular, for the water supplies of California, Central America and countries of Near East is also considered expedient. For these purposes, it is proposed that major Ocean currents be used.

Transporting Greenland icebergs, particularly to the shores of Germany has been proposed, where many regions also suffer from a shortage of a water. There are projects to use icebergs on polar stations and in Arctic region settlements.

The problem of qualitative exhaustion of waters in industrially-developed countries and also in a number of oil producing countries is so great, that icebergs have attracted attention as sources of clean, fresh water. However iceberg transportation projects have been delayed because of the unpredictability of ecological consequences.

 One of the real and yet little-studied problems of the present time is the use of the huge resources of marine water for the needs of industry and agriculture. The development of new engineering processes, with an allowance made for natural and chemical properties naturally occurring in sea water, will allow Mankind to use it with a high degree of effectiveness.

Marine water already finds uses for enrichment of mineral wealth, transporting of raw material and residues and as a coolant in steam generators. Having electrolytic and other properties, it can be used during concentration and deposition of suspended particles, for maintaining pressure in oil and natural gas-bearing strata, for solvents and for many other purposes.

 The primary percentage of marine water is used for cooling. Seaside thermal-electric power stations and nuclear power stations in various regions use from 33 to 75% of the total volume of the marine water supply available to them.

In agriculture, marine water is used in treating sewage, washing fruit and vegetables, watering cattle, growing water-fowl in lagoons and flood plains, etc. Sea water is used for watering plants in the USA, Spain, islands of Pacific, Atlantic and Indian Oceans, and also on the coasts of the Baltic, North and Mediterranean Seas, the Arabian peninsula, India and Australia.