Ocean current

An ocean current is a continuous, directed movement of seawater created by many forces, such as wind, the Coriolis effect, and differences in temperature and salinity. These currents can flow horizontally across entire oceans or vertically, moving nutrients and gases like carbon dioxide between the surface and deep ocean.

Ocean currents are either warm or cold and can be drifts, currents, or streams depending on their speed and direction. They shape climate zones and weather patterns worldwide. For example, the Gulf Stream makes northwest Europe much warmer than other areas at the same latitude.

The largest ocean current is the Antarctic Circumpolar Current, which flows clockwise around Antarctica, connecting all the oceanic basins and linking the atmosphere with the deep ocean. Together, ocean currents form a global conveyor belt that helps determine Earth’s climate.

Causes

Ocean currents are the continuous movement of seawater and are driven by several forces. The main forces include wind, the pull of the Moon creating tides, and differences in water density caused by temperature and salt levels. These forces work together to create the motion of water within the oceans.

There are two main types of currents: surface currents and deep-water currents. Surface currents are mostly pushed by wind, while deep-water currents are driven by changes in water density due to temperature and saltiness. The way these currents move can be influenced by the shape of the ocean floor and the Earth's rotation.

Effects on climate and ecology

Ocean currents help decide temperatures all around the world. For example, the current that brings warm water to parts of Europe stops ice from forming near the shore, which helps ships reach ports. This shows how currents shape the weather of places they flow through. They also matter for things like floating trash in the sea.

Cold currents from colder parts of the world bring nutrients to the surface. These nutrients help tiny plants called plankton grow, which many sea animals eat. Currents also help spread animals and plants, even moving baby fish and plants far away. They can even carry land animals like tortoises on floating objects to new islands.

Ocean currents and climate change

The rise in temperatures in the air is expected to change how strong surface ocean currents are, how they move, and how they spread things around. Ocean currents help shape our climate, and changes in climate can, in turn, change these currents.

Over the past hundred years, we have seen that some important currents along coastlines are warming up faster than the rest of the ocean. This warming may make these currents stronger and could keep getting stronger. There are also ideas that a big current in the Atlantic might slow down or even stop because of climate change, which could change the weather in northern Europe. Another big current around Antarctica is also slowing down and might lose a lot of its strength by 2050. Wind patterns, which also affect currents, are changing because of both climate change and natural processes. These changes in currents can affect where marine animals and plants end up, possibly moving some species toward the poles and deeper water, which could change the balance of ocean life.

Economic importance

Knowing about surface ocean currents helps save money on shipping because ships use less fuel when they travel with the currents. In the time of sailing ships, understanding wind patterns and ocean currents was very important. Ships used currents to help them reach ports and return home. Not knowing about these currents may have caused some exploration failures.

Today, ocean currents can help with sailing races and even provide power for machines in places like Japan, Florida, and Hawaii. Currents also affect the fishing industry. For example, currents like the Tsugaru, Oyashio, and Kuroshio change the temperature of the western North Pacific, which helps determine where fish like Skipjack tuna live. Even currents from nearby areas can influence a country's fishing industry.

Distribution

Currents of the Arctic Ocean

• Baffin Island Current – Arctic Ocean current
• Beaufort Gyre – Wind-driven ocean current in the Arctic Ocean polar region
• East Greenland Current – Current from Fram Strait to Cape Farewell off the eastern coat of Greenland
• East Iceland Current – Cold water ocean current that forms as a branch of the East Greenland Current
• Labrador Current – Western North Atlantic Ocean current
• North Icelandic Jet – Deep-reaching current that flows along the continental slope of Iceland
• Norwegian Current – Current that flows northeasterly along the Atlantic coast of Norway
• Transpolar Drift Stream – Current in the Arctic Ocean
• West Greenland Current – Weak cold water current that flows to the north along the west coast of Greenland
• West Spitsbergen Current – Warm, salty current that runs poleward just west of Spitsbergen

Currents of the Atlantic Ocean

• Angola Current – Temporary ocean surface current
• Antilles Current – Ocean current
• Atlantic meridional overturning circulation – System of surface and deep currents in the Atlantic Ocean
• Azores Current – Ocean current in the North Atlantic Ocean
• Benguela Current – Ocean current in the South Atlantic
• Brazil Current – Water current along Brazil's southern coast
• Canary Current – Wind-driven surface current that is part of the North Atlantic Gyre
• Cape Horn Current – Cold water current that flows west-to-east around Cape Horn
• Caribbean Current – Atlantic Ocean current
• East Greenland Current – Current from Fram Strait to Cape Farewell off the eastern coat of Greenland
• East Iceland Current – Cold water ocean current that forms as a branch of the East Greenland Current
• Equatorial Counter Current – Shallow eastward flowing current found in the Atlantic, Indian, and Pacific Oceans
• Falkland Current – Northward cold water Atlantic Ocean current
• Florida Current – Thermal ocean current
• Guinea Current – Atlantic warm-water current off West Africa
• Gulf Stream – Warm Atlantic Ocean current
• Irminger Current – North Atlantic ocean current
• Labrador Current – Western North Atlantic Ocean current
• Lomonosov Current – Deep current in the Atlantic Ocean. from the coast of Brazil to the Gulf of Guinea
• Loop Current – Ocean current between Cuba and Yucatán Peninsula
• North Atlantic Current – Current of the Atlantic Ocean
• North Brazil Current – North Atlantic ocean current
• North Equatorial Current – Current in the Pacific and Atlantic Oceans
• Norwegian Current – Current that flows northeasterly along the Atlantic coast of Norway
• Portugal Current – Weak ocean current that flows south along the coast of Portugal
• South Atlantic Current – Eastward ocean current, fed by the Brazil Current
• South Equatorial Current – Ocean current in the Pacific, Atlantic, and Indian Ocean
• West Greenland Current – Weak cold water current that flows to the north along the west coast of Greenland
• West Spitsbergen Current – Warm, salty current that runs poleward just west of Spitsbergen

Currents of the Indian Ocean

• Agulhas Current – Southwest Indian Ocean current off Africa's east coast
• Agulhas Return Current – Ocean current in the southern Indian Ocean
• East Madagascar Current – Oceanic flow feature near Madagascar
• Equatorial Counter Current – Shallow eastward flowing current found in the Atlantic, Indian, and Pacific Oceans
• Indian Monsoon Current – Seasonally-varying ocean current regime in the northern Indian Ocean
• Indonesian Throughflow – Ocean current
• Leeuwin Current – Ocean current off Western Australia
• Madagascar Current – Ocean current in the West Indian Ocean
• Mozambique Current – Warm ocean current in the Indian Ocean
• North Madagascar Current – Ocean current near Madagascar that flows into the South Equatorial Current
• Somali Current – Boundary current in the Indian Ocean
• South Equatorial Current – Ocean current in the Pacific, Atlantic, and Indian Ocean
• Southwest Madagascar Coastal Current – Warm poleward ocean current flowing in the south-west of Madagascar
• West Australian Current – Cool oceanic current

Currents of the Pacific Ocean

• Alaska Current – Warm-water current west of North America
• Aleutian Current – Eastward-flowing ocean current which lies north of the North Pacific Current;
• California Current – Pacific Ocean current
• Cape Horn Current – Cold water current that flows west-to-east around Cape Horn
• Cromwell Current – Eastward-flowing subsurface current that extends along the equator in the Pacific Ocean
• Davidson Current – Countercurrent of the Pacific Ocean
• East Australian Current – Currents of the Pacific Ocean
• East Korea Warm Current – Ocean current in the Sea of Japan
• Equatorial Counter Current – Shallow eastward flowing current found in the Atlantic, Indian, and Pacific Oceans
• Humboldt Current – Current of the Pacific Ocean
• Indonesian Throughflow – Ocean current
• Kamchatka Current – Pacific Ocean current
• Kuroshio Current – North-flowing current in the northwest Pacific Ocean
• Mindanao Current – Narrow, southward-flowing ocean current along the southeastern coast of the Philippines
• Mindanao Eddy – Semi-permanent cold-ring ocean eddy near the Philippines
• North Equatorial Current – Current in the Pacific and Atlantic Oceans
• North Korea Cold Current – Cold water current in the Sea of Japan
• North Pacific Current – Ocean current, Japan to British Columbia
• Oyashio Current – Cold subarctic ocean current in the Pacific Ocean
• South Equatorial Current – Ocean current in the Pacific, Atlantic, and Indian Ocean
• Subtropical Countercurrent – Narrow eastward ocean current in the central North Pacific Ocean
• Tasman Front – Pacific Ocean current
• Tasman Outflow – Deepwater current that flows from the Pacific Ocean past Tasmania into the Indian Ocean

Currents of the Southern Ocean

• Antarctic Circumpolar Current – Ocean current that flows clockwise from west to east around Antarctica
• Tasman Outflow – Deepwater current that flows from the Pacific Ocean past Tasmania into the Indian Ocean
• Kerguelen deep western boundary current

Oceanic gyres

• Beaufort Gyre – Wind-driven ocean current in the Arctic Ocean polar region
• Indian Ocean Gyre – Major oceanic gyre in the Indian Ocean
• North Atlantic Gyre – Major circular system of ocean currents
• North Pacific Gyre – Major circulating system of ocean currents
• Ross Gyre – Circulating system of ocean currents in the Ross Sea
• South Atlantic Gyre – Subtropical gyre in the south Atlantic Ocean
• South Pacific Gyre – Major circulating system of ocean currents
• Weddell Gyre – One of two gyres within the Southern Ocean