Q20. Which is a warm ocean current?
[Uttar Pradesh LT Grade Geography, 2018]
(A) Brazil Current
(B) Canary Current
(C) Labrador Current
(D) Benguela Current
Answer: (A) Brazil Current
Explanation: The Brazil Current carries warm water southward along eastern South America. The Canary, Labrador and Benguela currents are predominantly cold. Ocean-temperature contrasts influence fisheries, marine productivity and the climate of neighbouring coastal regions.
2017 — 5 questions
Q19. At which Indian beach does the sea retreat unusually far during low tide, allowing visitors to walk across the exposed seabed?
[UPSC Civil Services Preliminary Examination, 2017]
(A) Bhavnagar
(B) Bheemunipatnam
(C) Chandipur
(D) Nagapattinam
Answer: (C) Chandipur
Explanation: Chandipur beach in Odisha is famous for its conspicuous recession of seawater during low tide. The exposed intertidal zone changes with tidal cycles, illustrating how gravitational forces and local coastal topography affect the shoreline.
Q18. Which of these locations is associated with coral formations in Indian seas?
[MPPEB Examination, 11 January 2017]
(A) Rameswaram
(B) Ujjain
(C) Rajasthan
(D) Madurai
Answer: (A) Rameswaram
Explanation: Rameswaram lies near the Gulf of Mannar, where coral reefs occur in shallow marine waters. Ujjain, Rajasthan and Madurai are inland locations. Reefs contribute to biodiversity, fisheries habitat and coastal protection in suitable warm-sea environments.
Q17. Which phenomenon is a major cause of coral bleaching?
[MPPSC Assistant Professor Geography, 2017]
(A) Cold currents alone
(B) Ocean pollution alone
(C) Global warming and marine heat stress
(D) Higher salinity alone
Answer: (C) Global warming and marine heat stress
Explanation: Coral bleaching occurs when environmental stress, especially sustained high seawater temperature, causes corals to expel or lose symbiotic algae. The resulting loss of colour also reduces energy supply and can lead to mortality if stressful conditions persist.
Q16. Which ocean-current pair is INCORRECTLY matched with its temperature category?
[RPSC Preliminary Examination, 2017]
(A) Benguela—cold
(B) Canary—warm
(C) Agulhas—warm
(D) Humboldt—cold
Answer: (B) Canary—warm
Explanation: The Canary Current is a cold eastern-boundary current of the North Atlantic. Benguela and Humboldt are also cold, whereas Agulhas is warm. These patterns strongly affect coastal productivity through upwelling and influence regional weather.
Q15. Nekton are best described as which aquatic organisms?
[WBCS Preliminary Examination, 2017]
(A) Organisms floating passively with water
(B) Organisms that actively swim in water
(C) Animals living only on aquatic plants
(D) Submerged rooted plants
Answer: (B) Organisms that actively swim in water
Explanation: Nekton include active swimmers such as fish, squid and marine mammals, which can move against currents. Plankton largely drift with the water, while benthic organisms live on or in the seabed. These categories help describe marine food webs.
2016 — 2 questions
Q14. Which of the following currents does NOT belong to the Pacific Ocean?
[UKPSC Examination, 2016]
(A) Canary Current
(B) Kuroshio Current
(C) California Current
(D) Humboldt Current
Answer: (A) Canary Current
Explanation: The Canary Current flows in the northeastern Atlantic along northwestern Africa. Kuroshio, California and Humboldt are Pacific current systems. Understanding their location helps explain marine heat transport, upwelling and productive fishing grounds.
Q13. Which ocean current flows along the northwestern coast of Africa?
[Navodaya Vidyalaya Samiti TGT, 2016]
(A) Falkland Current
(B) Benguela Current
(C) Canary Current
(D) Agulhas Current
Answer: (C) Canary Current
Explanation: The Canary Current flows southwestward along northwest Africa and is generally cold. Coastal upwelling associated with this eastern Atlantic boundary enhances nutrients and plankton, creating productive marine fisheries in the surrounding region.
2015 — 3 questions
Q12. Which factors are responsible for ocean tides?
1. Gravitational attraction of the Sun;
2. Gravitational attraction of the Moon;
3. Centrifugal force associated with the Earth–Moon system.
[UPSC Civil Services Preliminary Examination, 2015]
(A) 1 only
(B) 2 and 3 only
(C) 1 and 3 only
(D) 1, 2 and 3
Answer: (D) 1, 2 and 3
Explanation: Tides arise mainly from the differential gravitational pull of the Moon and, to a lesser extent, the Sun, together with inertial effects in the Earth–Moon system. Their timing and range are important for intertidal ecosystems and coastal operations.
Q11. What explains the eastward movement of the Equatorial Countercurrent?
[UPSC Civil Services Preliminary Examination, 2015]
(A) Earth’s rotation alone
(B) Convergence and accumulation of water driven westward by equatorial currents
(C) High salinity of eastern ocean waters
(D) Equatorial calm conditions alone
Answer: (B) Convergence and accumulation of water driven westward by equatorial currents
Explanation: North and South Equatorial Currents push surface water westward, creating a sea-level and pressure gradient. Part of the accumulated water then returns eastward as the Equatorial Countercurrent. This circulation influences tropical ocean temperature and nutrient patterns.
