Ocean Currents Archives

1. Which one of the following is not a ‘cold ocean current’?

Which one of the following is not a ‘cold ocean current’?

Benguela Current

Canary Current

Falkland Current

Kuroshio Current

This question was previously asked in

UPSC CBI DSP LDCE – 2023

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The Kuroshio Current is a warm ocean current, unlike the other options which are cold currents.

Ocean currents are classified as warm or cold based on whether they carry water from warmer regions to colder regions (warm currents) or from colder regions to warmer regions (cold currents). The Benguela Current flows northwards along the west coast of southern Africa, originating from the Southern Ocean (cold). The Canary Current flows southwards along the northwestern coast of Africa, originating from the North Atlantic (cold). The Falkland Current flows northwards along the coast of Argentina, originating from the Southern Ocean (cold). The Kuroshio Current flows northeastwards from the east coast of Taiwan towards Japan and beyond, originating from the tropics (warm).

Warm currents typically flow towards the poles along the eastern coasts of continents (except in high latitudes), while cold currents typically flow towards the equator along the western coasts of continents (except in high latitudes). These currents play a crucial role in regulating global climate and influencing marine ecosystems.

2. Consider the following statements: 1. In the tropical zone, the west

Consider the following statements:

1. In the tropical zone, the western sections of the oceans are warmer than the eastern sections owing to the influence of trade winds.
2. In the temperate zone, westerlies make the eastern sections of oceans warmer than the western sections.

Which of the statements given above is/are correct?

1 only

2 only

Both 1 and 2

Neither 1 nor 2

This question was previously asked in

UPSC IAS – 2021

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Statement 1 is correct. In the tropical zone, the trade winds blow from east to west, pushing warm surface water towards the western side of ocean basins. This leads to a pile-up of warm water on the western side, making it warmer than the eastern side. Examples include the Gulf Stream (western Atlantic) and Kuroshio Current (western Pacific). Statement 2 is incorrect. In the temperate zone, while westerlies are the prevailing winds, the general ocean circulation patterns (driven by a combination of winds, Earth’s rotation – Coriolis effect, and density differences) result in warm currents flowing poleward on the western side of ocean basins and cold currents flowing equatorward on the eastern side. Therefore, the western sections of ocean basins are generally warmer than the eastern sections in the temperate zone as well, due to the transport of heat from the tropics. For example, the western side of the North Atlantic (near the US East Coast) is warmer than the eastern side (near Europe) at the same latitude due to the Gulf Stream. However, the Gulf Stream carries this warm water to Europe’s western coast, making Europe warmer than North America at similar latitudes. The statement says “eastern sections of oceans warmer than the western sections” which is generally false in the temperate zone for the ocean basin as a whole.

– Trade winds cause warm water to accumulate on the western side of tropical ocean basins.
– Westerlies are dominant winds in temperate zones but oceanic circulation patterns maintain warmer waters on the western side of ocean basins and colder waters on the eastern side in these latitudes.
– Boundary currents like the Gulf Stream and Kuroshio are warm western boundary currents flowing poleward.
– Boundary currents like the California Current and Canary Current are cold eastern boundary currents flowing equatorward.

The large-scale wind-driven surface ocean circulation forms gyres. In both the tropical and temperate zones, within these gyres, there are strong, narrow western boundary currents (like the Gulf Stream) and weaker, broader eastern boundary currents (like the California Current). These dynamics contribute to the western side of ocean basins being generally warmer than the eastern side in both zones.

3. What explains the eastward flow of the equatorial counter-current?

What explains the eastward flow of the equatorial counter-current?

The Earth's rotation on its axis

Convergence of the two equatorial currents

Difference in salinity of water

Occurrence of the belt of calm near the equator

This question was previously asked in

UPSC IAS – 2015

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The eastward flow of the equatorial counter-current is primarily explained by the pressure gradient created by the ‘pile-up’ of water in the western equatorial ocean, which is allowed to flow back eastward in the belt of calm near the equator.

The persistent westward-blowing trade winds in the tropics push surface water westward, causing it to accumulate in the western part of the ocean basin (e.g., western Pacific, western Atlantic). This creates a higher sea level and a pressure gradient sloping downwards towards the east. In the doldrums (Intertropical Convergence Zone – ITCZ), a belt of low pressure and calm or weak winds near the equator, the wind stress is minimal. With reduced opposition from wind, the water flows eastward down this pressure gradient, forming the Equatorial Counter-Current.

While other factors influence ocean currents, the primary driving mechanism for the eastward equatorial counter-current is the interplay between the westward-flowing trade winds, the resulting pressure gradient caused by water accumulation in the west, and the presence of the doldrums where this eastward flow is not inhibited by strong winds. The Earth’s rotation (Coriolis effect) causes deflection, but not the primary eastward flow. Salinity differences mainly influence deeper thermohaline circulation.

4. The most important fishing grounds of the world are found in the regio

The most important fishing grounds of the world are found in the regions where

warm and cold atmospheric currents meet

rivers drain out large amounts of freshwater into the sea

warm and cold oceanic currents meet

continental shelf is undulating

This question was previously asked in

UPSC IAS – 2013

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The most important fishing grounds of the world are typically found where warm and cold oceanic currents meet. This is because the meeting of currents causes upwelling, bringing nutrient-rich cold water from the ocean depths to the surface. This nutrient supply supports a large growth of plankton, which forms the base of the marine food web, leading to high populations of fish and other marine life.

The convergence of different oceanic currents, especially warm and cold ones, is a major factor in creating productive marine environments suitable for large-scale fishing. Upwelling associated with these areas is key to nutrient availability.

Examples of major fishing grounds located at the convergence of currents include the Grand Banks off Newfoundland (meeting of the warm Gulf Stream and the cold Labrador Current) and the North Sea (meeting of the North Atlantic Drift and polar waters). The continental shelf is also important because it is shallow enough for sunlight penetration, supporting photosynthesis, but the current mixing provides the significant boost in productivity.

5. Match List I with List II and select the correct answer using the code

Match List I with List II and select the correct answer using the code given below the Lists :

List I (Ocean Current)	List II (Location)
A. Kuroshio Current	1. Antarctic Ocean
B. Agulhas Current	2. Pacific Ocean
C. East Wind Drift	3. Atlantic Ocean
D. Antilles Current	4. Indian Ocean

Code :

3 4 1 2

3 1 4 2

2 1 4 3

2 4 1 3

This question was previously asked in

UPSC CAPF – 2024

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The correct match is A-2, B-4, C-1, D-3.

Kuroshio Current is in the North Pacific Ocean. Agulhas Current is in the Indian Ocean off the southeast coast of Africa. East Wind Drift is a current flowing around Antarctica in the Southern Ocean/Antarctic Ocean. Antilles Current is in the Atlantic Ocean, north of the Caribbean Sea.

Ocean currents are major features of ocean circulation patterns and play a crucial role in climate regulation and marine ecosystems. Matching specific currents to their respective ocean basins is a common geography topic.

6. Which one of the following is not correct?

Which one of the following is not correct?

The Gulf Stream is a warm ocean current.

The North Atlantic Drift is a warm ocean current.

The Labrador Current is a cold ocean current.

The California Current is a warm ocean current.

This question was previously asked in

UPSC CAPF – 2022

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The California Current is a cold ocean current, not warm. It flows southward along the west coast of North America, bringing cooler water from higher latitudes towards the equator.

Ocean currents are classified as warm or cold based on their temperature relative to the surrounding water and the region they flow through. Warm currents typically flow from equatorial regions towards the poles, while cold currents flow from polar regions towards the equator.

The Gulf Stream and North Atlantic Drift are warm currents transporting heat towards Europe. The Labrador Current is a cold current flowing from the Arctic south along the coast of Labrador and Newfoundland. The California Current is a cold current influencing the climate of the North American west coast.

7. Which one of the following ocean currents is not a warm current?

Which one of the following ocean currents is not a warm current?

North Pacific

Falkland

North Equatorial

Canary

This question was previously asked in

UPSC CAPF – 2018

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The Falkland current is not a warm current; it is a cold current.

– Ocean currents are broadly classified as warm or cold based on their temperature relative to the surrounding water and whether they bring water from warmer or colder regions.
– The North Pacific Current is part of the North Pacific Gyre and is considered a warm current, carrying warm water eastward across the Pacific.
– The Falkland Current (also known as the Malvinas Current) is a cold current flowing northward along the Atlantic coast of Patagonia, originating from the Antarctic Circumpolar Current.
– The North Equatorial Current (e.g., North Atlantic or North Pacific) flows westward in the tropical regions and carries warm water.
– The Canary Current is a cold current flowing southward along the northwestern coast of Africa, part of the North Atlantic Gyre’s eastern boundary.

The question asks for the current that is “not a warm current”. Both the Falkland Current (B) and the Canary Current (D) are classified as cold currents. However, typically in such multiple-choice questions, only one option is intended as correct. Based on common interpretations of this specific question structure in similar exams, the Falkland Current is often identified as the intended ‘not warm’ (cold) current among these options. The Falkland Current’s connection to Antarctic waters makes it a very distinct cold current.

8. The Sargasso Sea is a vast patch of Atlantic Ocean characterized by an

The Sargasso Sea is a vast patch of Atlantic Ocean characterized by an abundance of floating brown seaweed called ‘Sargassum’. This is formed due to the deposit of marine plants and refuse carried by the :
1. North Atlantic current
2. Canary current
3. North Atlantic Equatorial current
Select the correct answer using the code given below :

1 only

2 and 3 only

1 and 3 only

1, 2 and 3

This question was previously asked in

UPSC CAPF – 2014

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The Sargasso Sea is a region in the North Atlantic Ocean that is bounded by the currents forming the North Atlantic Gyre.

The currents that form the North Atlantic Gyre and trap the Sargassum seaweed are the Gulf Stream (to the west), the North Atlantic Current (to the north), the Canary Current (to the east), and the North Atlantic Equatorial Current (to the south). All three currents listed in the options (North Atlantic current, Canary current, North Atlantic Equatorial current) are part of the boundary currents that define and circulate around the Sargasso Sea, contributing to the accumulation of floating material within it.

The Sargasso Sea is unique as it is the only sea in the world that is defined by ocean currents rather than by land boundaries. Its calm, clear waters are home to a unique ecosystem, including the Sargassum seaweed which provides habitat for numerous marine species. The lack of strong currents within the gyre allows the seaweed and other floating debris to accumulate.

9. The Kuroshio is a north flowing Ocean current on the west side of the

The Kuroshio is a north flowing Ocean current on the west side of the North Pacific Ocean. Which one among the following statements regarding this is not correct ?

It is similar to the Gulf Stream in the North Atlantic Ocean

It transports warm, tropical water northward towards the Polar region

The warm water of the Kuroshio current sustains the coral reefs of Japan

It begins off the coast of Japan and flows northward

This question was previously asked in

UPSC CAPF – 2014

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The correct answer is It begins off the coast of Japan and flows northward.

Let’s examine each statement about the Kuroshio current:
A) It is similar to the Gulf Stream in the North Atlantic Ocean: Both are strong, warm, western boundary currents in the Northern Hemisphere. This statement is correct.
B) It transports warm, tropical water northward towards the Polar region: This is the primary function and characteristic of a warm current flowing poleward. This statement is correct.
C) The warm water of the Kuroshio current sustains the coral reefs of Japan: The warm waters allow coral reefs to exist in higher latitudes than they otherwise could. Southern Japan (Ryukyu Islands) and parts of the mainland coast influenced by the Kuroshio have coral reefs. This statement is correct.
D) It begins off the coast of Japan and flows northward: The Kuroshio current originates from the North Equatorial Current in the western Pacific, flowing westwards and then turning north near the Philippines and Taiwan. It then flows northward along the east coast of Japan before turning eastward into the North Pacific as the Kuroshio Extension. Therefore, it flows *along* the coast of Japan but does *not* begin there. Its origin is further south and west. This statement is incorrect.

The Kuroshio, also known as the Japan Current, plays a significant role in the climate and marine ecosystems of the region, influencing temperatures, precipitation patterns, and marine life distribution.

10. Which one among the following ocean currents mixes with Labrador

Which one among the following ocean currents mixes with Labrador current?

Canaries current

Benguela current

Florida current

California current

This question was previously asked in

UPSC CAPF – 2013

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The correct answer is C. The Labrador Current, a cold current, mixes with the warm waters originating from the Gulf Stream system, which includes the Florida Current.

– The Labrador Current flows from the Arctic Ocean southward along the coast of Labrador and Newfoundland.
– It meets the Gulf Stream system off the Grand Banks of Newfoundland.
– The Gulf Stream is a powerful warm ocean current that flows from the Gulf of Mexico and the Caribbean Sea northward into the Atlantic Ocean. The Florida Current is a component of the Gulf Stream, flowing through the Florida Straits.

The mixing of the cold Labrador Current and the warm Gulf Stream waters creates the fog commonly found on the Grand Banks and is also a significant area for marine life and fishing. Other options like the Canaries Current (off NW Africa), Benguela Current (off SW Africa), and California Current (off West USA) are in different ocean basins or flow regimes.