Oceans: Storehouse of Resources.


Earth is the third planet from the Sun and the only astronomical object known to harbour life. About 71% of Earth's surface is covered with water, mostly by oceans. The remaining 29% is land consisting of continents and islands that together contain many lakes, rivers and another freshwater. Within the first billion years of Earth's history, life appeared in the oceans and began to affect Earth's atmosphere and surface, leading to the proliferation of anaerobic and, later, aerobic organisms.



An ocean is a body of water that composes much of a planet's hydrosphere. On Earth, an ocean is one of the major conventional divisions of the World Ocean. These are, in descending order by area, the Pacific, Atlantic, Indian, Antarctic, and Arctic Oceans. The phrases "the ocean" or "the sea" used without specification refer to the interconnected body of saltwater covering the majority of the Earth's surface.

Saline seawater covers approximately 361,000,000 km2 and is customarily divided into several principal oceans and smaller seas, with the ocean covering approximately 71% of Earth's surface. The ocean contains 97% of Earth's water, the total volume is approximately 1.35 billion cubic kilometres with an average depth of nearly 3,700 meters.


As the world ocean is the principal component of Earth's hydrosphere, it is integral to life, forms part of the carbon cycle, and influences climate and weather patterns. The World Ocean is the habitat of 230,000 known species, but because much of it is unexplored, the number of species that exist in the ocean is much larger, possibly over two million. The origin of Earth's oceans is unknown; Oceans are thought to have formed in the Hadean eon and may have been the cause for the emergence of life.

Oceans: Storehouse of Resources

Oceans cover 70 per cent of Earth's surface, host a vast variety of geological processes responsible for the formation and concentration of mineral resources, and are the ultimate repository of many materials eroded or dissolved from the land surface. Hence, oceans contain vast quantities of materials that presently serve as major resources for humans. Today, direct extraction of resources is limited to salt; magnesium; placer gold, tin, titanium, and diamonds; and freshwater.

Ancient ocean deposits of sediments and evaporites now located on land were originally deposited under marine conditions. These deposits are being exploited on a very large scale and in preference to modern marine resources because of the easier accessibility and lower cost of terrestrial resources. Yet the increasing population and the exhaustion of readily accessible terrestrial deposits undoubtedly will lead to broader exploitation of ancient deposits and increasing extraction directly from ocean water and ocean basins.

Principal Mineral Resources:

Resources presently extracted from the sea or areas that were formerly in the sea range from common construction materials to high-tech metals to water itself. Chemical analyses have demonstrated that seawater contains about 3.5 per cent dissolved solids, with more than sixty chemical elements identified. The limitations on the extraction of the dissolved elements as well as the extraction of solid mineral resources are nearly always economic, but may also be affected by geographic location (ownership and transport distance) and hampered by technological constraints (depth of ocean basins).

The principal mineral resources presently being extracted and likely to be extracted in the near future are briefly considered here.


Salt, or sodium chloride, occurs in seawater at a concentration of about 3 per cent and hence constitutes more than 80 per cent of the dissolved chemical elements in seawater. The quantity available in all the oceans is so enormous that it could supply all human needs for hundreds, perhaps thousands, of years. Although salt is extracted directly from the oceans in many countries by evaporating the water and leaving the residual salts, most of the nearly 200 million metric tons of salt produced annually is mined from large beds of salt. These beds, now deeply buried, were left when waters from ancient oceans evaporated in shallow seas or marginal basins, leaving residual thick beds of salt; the beds were subsequently covered and protected from solution and destruction.

Salt Farming


Like the sodium and chlorine of salt, potassium occurs in vast quantities in seawater, but its average concentration of about 1,300 parts per million (or 0.13 per cent) is generally too low to permit direct economic extraction. Potassium salts, however, occur in many thick evaporite sequences along with common salt and is mined from these beds at rates of tens of millions of metric tons per year. The potassium salts were deposited when seawater had been evaporated down to about one-twentieth of its original volume.


Magnesium, dissolved in seawater at a concentration of about 1,000 parts per million, is the only metal directly extracted from seawater. Presently, approximately 60 per cent of the magnesium metal and many of the magnesium salts produced in the United States are extracted from seawater electrolytically. The remaining portion of the magnesium metal and salts is extracted from ancient ocean deposits where the salts precipitated during evaporation or formed during diagenesis. The principal minerals mined for this purpose are magnesite and dolomite.

Minirals from Oceans

Sand and Gravel:

The ocean basins constitute the ultimate depositional site of sediments eroded from the land, and beaches represent the largest residual deposits of sand. Although beaches and near-shore sediments are locally extracted for use in construction, they are generally considered too valuable as recreational areas to permit removal for construction purposes. Nevertheless, older beach sand deposits are abundant on the continents, especially the coastal plains, where they are extensively mined for construction materials, glass manufacture, and preparation of silicon metal. Gravel deposits generally are more heterogeneous but occur in the same manner, and are processed extensively for building materials.


Limestone and Gypsum:

Limestones (rocks composed of calcium carbonate) are forming extensively in the tropical to semitropical oceans of the world today as the result of precipitation by biological organisms ranging from molluscs to corals and plants. There is little exploitation of the modern limestones as they are forming in the oceans. 

However, the continents and tropical islands contain vast sequences of limestones that are extensively mined; these limestones commonly are interspersed with dolomites that formed through diagenetic alteration of limestone. Much of the limestone is used directly in cut or crushed form, but much is also calcined (cooked) to be converted into cement used for construction purposes. Gypsum (calcium sulphate hydrate) forms during evaporation of seawater and thus may occur with evaporite salts and/or with limestones. The gypsum deposits are mined and generally converted into plaster of Paris and used for construction.

Manganese Nodules:

The deep ocean floor contains extremely large quantities of nodules ranging from centimetres to decimetres in diameter (that is, from less than an inch to several inches). Although commonly called manganese nodules, they generally contain more iron than manganese but do constitute the largest known resource of manganese.

Despite the abundance and the wealth of metals contained in manganese nodules (iron, manganese, copper, cobalt, and nickel), no economic way has yet been developed to harvest these resources from the deep ocean floor. Consequently, these rich deposits remain as potential resources for the future. Terrestrial deposits of manganese are still relied on to meet human needs.


Complex organic and inorganic processes constantly precipitate phosphate-rich crusts and granules in shallow marine environments. These are the analogy (comparative equivalents) of the onshore deposits being mined in several parts of the world, and represent future potential reserves if land-based deposits become exhausted.


Metal Deposits Associated with Volcanism and Seafloor Vents:

Submarine investigations of oceanic rift zones have revealed that rich deposits of zinc and copper, with associated lead, silver, and gold, are forming at the sites of hot hydrothermal emanations commonly called black smokers. These metal-rich deposits, ranging from the chimney to a pancake-like, from where deeply circulating seawater has dissolved metals from the underlying rocks and issue out onto the cold seafloor along with major fractures. The deposits forming today are not being mined because of their remote locations, but many analogous ancient deposits are being mined throughout the world.

Placer Gold, Tin, Titanium, and Diamonds:

Placer deposits are accumulations of resistant and insoluble minerals that have been eroded from their original locations of the formation and deposited along with river courses or at the ocean margins. The most important of these deposits contain gold, tin, titanium, and diamonds.


Today, much of the world's tin and many of the gem diamonds are recovered by dredging near-shore ocean sediments for minerals that were carried into the sea by rivers. Gold has been recovered in the past from such deposits, most notably in Nome, Alaska. Large quantities of placer titanium minerals occur in beach and near-shore sediments, but mining today is confined generally to the beaches or onshore deposits because of the higher costs and environmental constraints of marine mining.



The world's oceans, with a total volume of more than 500 million cubic kilometres, hold more than 97 per cent of all the water on Earth. However, the 3.5-per cent salt content of this water makes it unusable for most human needs.


The extraction of freshwater from ocean water has been carried out for many years, but provides only a very small portion of the water used, and remains quite expensive relative to land-based water resources. Technological advances, especially in reverse osmosis, continue to increase the efficiency of fresh-water extraction. However, geographic limitations and dependency on world energy costs pose major barriers to large-scale extraction.


The ocean is one of Earth's most valuable natural resources. It provides food in the form of fish and shellfish—about 200 billion pounds are caught each year. The oceans have been fished for thousands of years and are an integral part of human society. Fish have been important to the world economy for all of these years, starting with the Viking trade of cod and then continuing with fisheries like those found in Lofoten, Europe, Italy, Portugal, Spain and India. Fisheries of today provide about 16% of the total world’s protein with higher percentages occurring in developing nations. Fisheries are still enormously important to the economy and well-being of communities.

Sea Food

Oxygen Production:

Gases in the atmosphere like carbon, nitrogen, sulphur and oxygen are dissolved through the water cycle. The gases that are now crucial to all ecosystems and biological processes originally came from the inside layers of the earth during the period when the earth was first formed. The rate of flow for oxygen, as well as other gases, is controlled by biological processes, especially the metabolism of organisms like prokaryotes and bacteria. Prokaryotes have been around since the beginning of the Earth, have evolved to be able to use chemical energy to create organic matter and are capable of both reducing and oxidizing inorganic compounds. Bacteria that can reduce inorganic compounds are anaerobic and those that oxidize inorganic compounds are aerobic. Aerobic bacteria release oxygen as a by-product of photosynthesis.

Approximately two billion years ago, aerobic bacteria began producing oxygen which gradually filled up all of the oxygen reservoirs in the environment. Once these “sinks” were filled, molecular oxygen began to build in the atmosphere, creating an environment favourable for other life to inhabit the Earth. Sinks included reduced iron ions and hydrogen sulphide gas. Evidence of this process can be found in the banded iron formations created when iron minerals were precipitated. The oxygen started to fill the atmosphere up and new bacteria evolved that could use oxygen to oxidize both inorganic and organic compounds. Bacteria that were accustomed to an oxygen-poor atmosphere only survived in anaerobic environments like sewage, swamps, and in the sediments of both marine and freshwater areas.


Phytoplankton accounts for possibly 90% of the world’s oxygen production because water covers about 70% of the Earth and phytoplankton are abundant in the photic zone of the surface layers. Some of the oxygen produced by phytoplankton is absorbed by the ocean, but most flows into the atmosphere where it becomes available for oxygen-dependent life forms.

The Ocean regulates the Earth climate:

In many ways, the sea regulates our climate. It soaks up the heat and transports warm water from the equator to the poles, and cold water from the poles to the tropics. Without these currents, the weather would be extreme in some regions, and fewer places would be habitable.

Oceans Current

It regulates rain and droughts. Holding 97% of the water of our planet, almost all rain that drops on land comes from the sea. The ocean absorbs CO2, to keep the carbon cycle, and accordingly temperatures on earth, in balance. It is like our global climate control system.

Oceans Current effecting Weather

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