(a) Highlight the economic importance of oceans to man, giving specific examples (b) Select any one warm current in the North Atlantic Ocean and describe th...

(a) Economic importance of oceans to man

1. Source of food: oceans provide fish and other sea foods; fishing grounds such as those off the coast of West Africa support the fishing industry.
2. Transportation: oceans are cheap natural highways for international trade; ships carry bulky goods across the Atlantic between Africa, Europe and America.
3. Source of minerals: petroleum and natural gas are obtained from the continental shelf (e.g. Gulf of Guinea), and common salt is obtained by evaporating sea water.
4. Generation of power: tidal and wave energy can be harnessed to produce electricity.
5. Tourism and recreation: beaches and coastal resorts attract tourists and provide income, for example along the Mediterranean coast.
6. Source of fresh water: sea water is desalinated to provide fresh water in dry regions such as North Africa and the Middle East.
7. Influence on climate: oceans and their currents moderate temperatures and bring rain-bearing winds that support agriculture.

(b) A warm current in the North Atlantic and factors responsible for its movement

Selected current: the Gulf Stream / North Atlantic Drift, a warm current flowing from the Gulf of Mexico north-eastward across the Atlantic towards north-west Europe.

Factors responsible for its movement:

1. Prevailing winds: the trade winds drive the water westward across the tropics, and the westerlies then push the warm water north-eastward towards Europe.
2. Rotation of the earth (Coriolis force): deflects the moving water to the right in the Northern Hemisphere, guiding it into a clockwise circulation.
3. Differences in water temperature and density: warm, lighter equatorial water flows towards the colder, denser polar water, setting up movement.
4. Differences in salinity: variations in salt content cause density differences that help drive the current.
5. Shape of the coastline and ocean basin: the outline of the American and African coasts deflects and channels the flow of the current.