Causes Of Ocean Currents, Meaning, Types, Effects

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Hi, welcome to this blog on Ocean Currents types and causes.

Table Of Contents

  1. Meaning of Ocean Currents
  2. Types of Ocean currents
  3. Causes of Ocean currents
  4. Distribution of ocean current according to oceans and their hemisphere.
  5. Effect of ocean Currents on adjacent coastal area

Meaning of Ocean Current

Meaning: Ocean current refers to the regular movement of water from one part of the ocean to another. In other words, they are large masses of surface water that circulates in regular patterns around the ocean.

Types of Ocean Currents

Ocean currents are grouped into two major types which are, warm current and cold currents.

  1. Warm current: Warm currents are those that flows from the equatorial regions towards the poles and have a relatively low surface temperature.
  2. Cold current: Cold current are those that flows from the poles towards equatorial regions and have a relatively low surface temperature..

Causes Of Ocean Currents

Ocean currents are caused by the following factors:

  1. Planetary wind
  2. Rotation of the Earth
  3. Temperature differences
  4. Shape of the Land masses
  5. Salinity.

1. Planetary wind

  • Wind is one of the most important factors responsible for the movement of surface water in Oceans.
  • The trade wind moves equatorial water pole-wards and westwards and warm the eastern coast of the continents. For example, the North East trade winds move the North equatorial current to warm the Southern and Eastern coasts of U.S.A
  • Also, the South East trade wind drive the South equatorial current which warms the eastern coasts of Brazil, e.g, Brazilian current.

2. Rotation of the Earth

  • As a result of the rotation of the Earth, ocean Waters are deflected to the right in northern hemisphere and to the left in the Southern hemisphere.

3. Temperature differences

  • Ocean Waters at the equator are more heated and therefore warmer and lighter than those are the poles.
  • Thus, those at the equator flow on the ocean surface towards the pole.
  • Those at the poles are cold and heavy, thus creeping below the bottom of the ocean towards the equator.

4. Shape of the Land masses

  • Warm and cold current flow in obedience to the topography and configuration of the Land masses.
  • The landmass may divert the Currents from the direction initially taken by current to totally different directions.

5. Salinity

  • Where the salinity of an ocean is high, the ocean water is dense or heavy, and creeps or moves at the bottom of the ocean to low salinity areas.
  • But where the salinity is low, the ocean water is light and flows at the Ocean surface towards a high salinity area.

Distribution of ocean currents according to oceans and their hemisphere

(a) Northern hemisphere

1. The main warm ocean currents are:

Atlantic Ocean

  • Cayenne current
  • Florida current
  • Gulf stream current.
  • North Atlantic drift.
  • Guinea current.

Pacific Ocean

  • Kuroshio current.
  • Oyashio-Bering current.
  • North Pacific Drift.

2. The men called Ocean currents are:

Atlantic Ocean

  • Labrador current
  • Irminger current.
  • Canaries current.

Pacific Ocean

  • California current
  • Okhotsk current

(b) Southern hemisphere

1. The main warm ocean currents are;

Atlantic Ocean

  • Brazilian current
  • South Atlantic Drift

Pacific Ocean

  • Eastern Australian Current
  • South Pacific Drift

Indian Ocean

  • Mozambique current
  • South Indian Ocean Drift

2. The men cold ocean currents are:

Atlantic Ocean

  • Benguela current.
  • Falkland current.

Indian Ocean

  • West Australian Current.

Pacific Ocean

  • Peruvian Current.

Effect Of Ocean Current On Adjacent Coastal Areas

  1. It modifies the climate of an area: By either lowering the temperature if the current is cold or by raising it if it is warm.
  2. Contribute to Aridity: Cold current contribute to aridity (deserts) on the landmass they affect. e.g, Benguela current of west coast of South Africa causes Namid and Kalahari deserts. Also Canaries current of North-West Africa causes Sahara desert.
  3. Causes Coastal fogs: Cold current also cause coastal fogs instead of actual rain. This is a sort of danger as it reduces visibility for airplanes and sailors.
  4. Bring regular and heavy rainfall: Cold current brings regular and heavy rainfall to their coastlands, e.g, Mozambique current of South East Africa and Guinea current of West Africa bring rain to their coastland.
  5. Reduce the temperature of the areas: Coastal fogs caused by cold current reduce the temperature of the areas where they occur.
  6. Resist the temperature of adjacent land: Warm ocean currents, by warming the winds blowing over them raise the temperature of the adjacent lands.
  7. Free from ice: Warm ocean current help to keep Ports in polar regions free from ice.
  8. Release of plant nutrients: The meeting of warm and cold currents can be a blessing to the people of the place. Such meeting often brings about the release of plant nutrients and other micro-organisms which are good for fish, e.g, the Ground Banks of Newfoundland is noted as a great fishing ground.

Revision Questions

  1. (a) Explain the types of ocean Currents (b) Briefly state and discuss four causes of ocean Currents.
  2. Write short notes on benguela current and Guinea current.
  3. (a) Identify and explain any four factors which determine the direction of flow of ocean currents. (b) using specific examples discuss the effects of ocean current on the climate of the adjacent coastal area.
  4. What is the meaning of ocean Currents?
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