Ocean currents are continuous movements of ocean water that wind, breaking waves, temperature and salinity differences, and other forces acting upon the water generated. They are primarily horizontal water movements and often flow for great distances and create the global conveyor belt, which helps to determine the climate of different parts of the Earth.

There are hundreds of ocean currents that you can consider. However, some of them play a more important role than others.

This article focuses on six major ocean currents that play the most prominent role in shaping the Earth’s climate and ecosystems. Read on if you want to know the names of these ocean currents, how they are formed, their unique benefits, and more.

Gulf Stream

Major Feature: Formed by the movement of water in the Gulf of Mexico

Impact on the Environment?: Regulate the temperature of the North Atlantic region

The Gulf Stream is widely known as a warm surface current that flows from the Gulf of Mexico to the Atlantic coast of Europe. It carries warm water from the tropics to higher latitudes.

Map  of the Gulf Stream Current
Map of the Gulf Stream Current

This famous ocean current is formed by the movement of water in the Gulf of Mexico, which the sun warms and then flows into the Atlantic Ocean. As the water flows northward, the atmosphere cools and becomes denser, causing it to sink and flow back toward the equator. This sinking and flowing back of water is known as a ‘western boundary current,’ and it helps to drive the global ocean conveyor belt.

The Gulf Stream is an integral part of the Earth’s climate system because it helps to regulate the temperature of the North Atlantic region. It transports heat from the tropics to Western Europe, which helps to keep the region warm in winter. What’s more, it helps in the distribution of plants and animals around the world.

California Current

Major Feature: The cool, dry air of the Pacific Highinfluences it

Impact on the Environment?: Supports various species, including whales, dolphins, and seals.

If you are looking for cold surface currents that flow along the west coast of North America, you are in the right place. The California current suits this description, and it helps the North Pacific to carry cold water from the Arctic southward.

California Current when viewed from space
California Current when viewed from space

What causes the California current? The cool, dry air of the Pacific High, which results in relatively cool and nutrient-rich waters, influences it. It is also affected by the warmer, moister air of the Aleutian Low, which can bring warmer and less nutrient-rich waters. These temperature and nutrient content fluctuations can significantly impact the region’s marine life, including fish, seabirds, and mammals.

The California Current supports many species, including many commercially important fish species such as sardines, anchovies, and hake. It is also home to numerous marine mammal species, including whales, dolphins, and seals.

Kuroshio Current

Major Feature: The movement of water in the western Pacific Ocean forms it

Impact on the Environment?: Regulate the temperature of the North Pacific region

This is one of the major warm surface currents, and it flows along the east coast of Japan. The North Pacific ocean depends on it to carry warm water from the tropics northward.

Image showing the directions  of the Kuroshio Current
Image showing the directions of the Kuroshio Current

The Kuroshio Current is formed by the movement of water in the western Pacific Ocean, which is warmed by the sun and then flows northward along the east coast of Japan. As the water flows northward, it’s cooled by the atmosphere and becomes denser.

The Kuroshio Current helps to regulate the temperature of the North Pacific region. It transports heat from the tropics to Japan and other parts of East Asia, which is necessary for keeping the region warm in winter. At the same time, this current plays a role in the distribution of plants and animals worldwide, as many species use it as a highway to migrate between the tropics and higher latitudes.

Agulhas Current

Major Feature: Formed by the movement of water in the western Indian Ocean

Impact on the Environment?: Regulate the temperature of the Indian Ocean region

Map of Agulhas Current
Map of Agulhas Current

The Agulhas Current is found along the east coast of Africa and carries warm water from the tropics to higher latitudes. It is formed by the water movement in the western Indian Ocean, which is warmed by the sun and then flows southward along the east coast of Africa. Like in the other cases above, as the water flows southward, it is cooled by the atmosphere and becomes denser, causing it to sink and flow back toward the equator.

Additionally, it helps to regulate the temperature of the Indian Ocean region. It transports heat from the tropics to South Africa and other parts of southern Africa, which helps to keep the region warm in winter. The Agulhas Current also plays a role in the distribution of plants and animals worldwide, as many species use it as a highway to migrate between the tropics and higher latitudes.

Antarctic Circumpolar Current

Major Feature: Formed by the movement of water in the Southern Ocean

Impact on the Environment?: Regulate the temperature of the Southern Ocean region

 This is the world’s most extensive ocean current and is an essential part of the Southern Ocean Current, which carries cold water from the poles to the tropics. It’s also a cold surface current that flows around Antarctica.

Image of  the Antarctic Circumpolar Current as it circumnavigates the planet
Image of the Antarctic Circumpolar Current as it circumnavigates the planet

Credit: European Union, Copernicus Marine Environment Monitoring Service

The Antarctic Circumpolar Current is formed by the movement of water in the Southern Ocean, which is cooled by the atmosphere and then flows eastward around Antarctica. As the water flows eastward, a process almost the same as the one we’ve seen repeats itself. The sun warms this water, causing it to rise to the surface and flow back toward the west. This rising and flowing back of water is known as an ‘eastern boundary current.’ 

Are you thinking of what helps to regulate the temperature of the Southern Ocean region? It’s this current. It transports cold water from the poles to the tropics, which helps to keep the region cool in summer. The Antarctic Circumpolar Current also helps in the distribution of living things.

Thermohaline Circulation

Major Feature: Deep current that is driven by differences in water density

Impact on the Environment?: Regulate the temperature of the Earth’s surface

Thermohaline circulation is a deep current driven by water density differences caused by temperature and salinity variations. It carries warm water from the equator to higher latitudes and cold water from the poles back to the equator.

Image showing how  the  thermohaline circulation functions
Image showing how the thermohaline circulation functions

Credit: US Global Change Research Program

This current helps to distribute heat and nutrients throughout the ocean. Warm water from the tropics flows northward and southward, while cold water from the poles flows equatorward. As the warm water flows northward, it cools and becomes denser, causing it to sink and flow back toward the equator. As the cold water flows equatorward, it warms and becomes less dense, causing it to rise to the surface and flow back toward the poles. This sinking and rising of water are known as the “overturning circulation.” 

Benefits of Leading Ocean Currents

As we’ve seen, some of the most critical ocean currents are the Gulf, California, Kuroshio, Agulhas, Antarctic Circumpolar, and Thermohaline circulation. All of them help to regulate the Earth’s temperature and play a role in the distribution of some species of plants and animals worldwide. Deep currents distribute nutrients from deep parts of the ocean to other areas.

FAQs

What are surface ocean currents?

Surface currents are the most visible current driven by wind and the Earth’s rotation. Surface currents can be either warm or cold, depending on the temperature of the water. Examples of surface currents include the Gulf Stream, which flows from the Gulf of Mexico to the Atlantic coast of Europe, and the California Current, which flows along North America’s western coast.

Temperature and salinity variations drive which types of ocean currents?

Variations in temperature and salinity cause deep currents. They flow at several hundred meters or more depths and play a crucial role in distributing heat and nutrients throughout the oceans. One example of a deep current is the thermohaline circulation, which carries warm water from the equator to higher latitudes and cold water from the poles back to the equator.

How do ocean currents distribute nutrients?

Ocean currents distribute nutrients by picking up nutrients from the sea floor and carrying them to other parts of the world as the water flow. For example, the Agulhas Current carries nutrients from the western Indian Ocean to the east coast of Africa.
The ocean currents also distribute nutrients when surface water is pushed away from the coast by wind or the Earth’s rotation, allowing deep water rich in nutrients to rise to the surface.

Do ocean currents regulate the Earth’s temperature?

Yes, the circulation of heat through the oceans helps regulate the Earth’s temperature, especially in areas far from the equator. For example, the Gulf Stream helps to keep Western Europe warm in winter by transporting heat from the tropics to the region. Similarly, the Agulhas Current helps to keep southern Africa warm in winter by transporting heat from the tropics to the region.