The Ocean stores a large quantity of heat, hence it is often called “the saving bank for the solar energy, receiving deposits in season of excessive insolation and paying them back in seasons of want”.
The extensive deep waters of oceans gain as well as loose heat more slowly than the land when both are subjected to the same amount of insolation.
The oceans supply water vapour to the atmosphere and thus are the basic source of all precipitation on earth.
They are also the vital source of fresh water on earth.
Ocean currents are important regulators of temperature on the earth’s surface.
They help in exchange of heat between low and high latitudes and are essential in sustaining the global energy balance.
The ocean’s surface has six or more permanent centres of high pressure.
These high pressure areas give birth to the planetary wind system over the earth.
These planetary winds determine the amount of rainfall and its distribution over the earth’s surface.
The westerlies give rainfall on the West European Coast after collecting moisture from the warm North Atlantic Drift.
The animals and plants of the sea constitute a vast resource from which man can derive food, fertilizers for agriculture and raw material for industry.
Fish and other marine animals form a rich source of food and nutrition for man.
Fishes now make up more than 10 per cent of the total animal protein that human consume.
Oceans are the store house of a large number of useful metallic and nonmetallic minerals.
Foremost among the minerals are the petroleum deposits of the continental shelves.
Vast deposits of petroleum have been found in many places such as in the North Sea, off the coast of South California and Texas, in the Mediterranean Sea, Persian Gulf, and Bombay High in the Arabian Sea.
The common salt or sodium chloride is extracted from sea water.
Apart from salt, magnesium and bromine have long been extracted from sea water.
All the metallic elements are present in the seawater in some degree.
However waters and sediments of ocean are heavily saturated with such metals as zinc, copper, lead, silver and gold, especially in the volcanic region of the oceanic ridge.
The technology to exploit these minerals has not yet developed.
The most significant are mineral nodules found on the deep sea floor.
The important ones are phosphorites and manganese nodules.
The energy resources of the oceans are of various types – tidal power, geothermal energy and energy from the ocean temperature.
Tidal energy was in use even in the 12th Century.
Water wheels driven by the tides were used for grinding grain.
Today, efforts are being made to harness the energy to run electric generators.
A few tidal power stations are working in Russia, France and China.
Oceans act as natural link among continents and nations of the world.
They provide natural highways at low cost for international trade.
They facilitate movement of bulky goods.
The water is buoyant and needs less motive power.