Oceans occupies over 70 percent or 360 million square kilometres of the earth’s total area of 510 million square kilometres.
Oceanography is the study oceans, the water in the oceans,the movement of water and the economic significance of the ocean.The depth of the ocean is measured by a technique called Echo sound technique but this has been replaced by the radar sound technique.
TYPES OF OCEANS
There are four main types of oceans in the world and the rest constitute the seas.
- Pacific ocean which occupies about 165 million km square
- Atlantic ocean which occupies 82 million km square
- Indian ocean which occupies about 74 million km square
- Arctic ocean which occupies about 14 million km square
- The seas which occupies 25 million km square
NOTE: Pacific ocean is the largest of all the oceans in the world
ECONOMIC IMPORTANCE OF OCEANS TO MAN
Means of transportation: Oceans are used in the world as a major means of transportation and communication between countries during international trade.
Tourism: Oceans,especially around the beaches and coasts are centres of tourist attraction e.g the bar beaches
Provision of food: Ocean also provide food for man especially proteins in form of fish,prawn,crabs,crayfish etc.
Provision of employment: Ocean also provide employment to many people e.g fishermen,sailors and ship builders.
Development of seaport: Seaports which have terminal points for ships are located on the coast e.g In Nigeria they have Apapa port in Lagos
Promotion of economic activities: International trade is made possible through oceans and many other economic activities such as ship building,transport.
Extraction of salt: Ocean water provides the raw materials from which domestic and industrial salts are extracted.
Sources of minerals: Some minerals like petroleum and natural gas are associated with the ocean. e.g In the continental shelf.
Provision of industrial products: Some seaweeds are known to be used by certain industries for the production of cosmetics.
Educational research: The ocean also provides a means for research in aquatic plants and animals that are useful to man e.g Institutes of oceanography and marine research.