Geography · Environmental Studies

Oceanography and Hydrology

1,743 Questions

Find relevant questions on oceanography and hydrology that address aquatic ecosystems and physical geography. The topics include coastal landforms, coral reefs, ocean salinity, and tidal patterns. These concepts frequently appear in civil services and state level administrative examinations.

Coral reef structuresCoastal landformsOcean salinity patternsGlacial retreat impactsMangrove ecosystems

Oceanography and Hydrology Questions

Multiple choice

Which one of the following sequences correctly indicates the increasing order of the distance from the coast?

  1. Abyssal plain-continental shelf-continental slope-continental rise

  2. Continental shelf-continental slope-abyssal plain-continental rise

  3. Continental shelf-continental slope-continental rise-abyssal plain

  4. Continental slope-continental shelf-abyssal plain-continental rise
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The distance from the coast increases progressively: continental shelf (0-200m depth, extending from coastline), continental slope (steeper descent), continental rise (gentle slope at base), and finally abyssal plain (deepest ocean floor, typically 4000-6000m).

Multiple choice

Consider the following statements:

  1. Where fold mountains runs parallel and close to the coast, continental shelf is narrow or absent

  2. The average depth for continental shelf is 100 metres.

  3. Submarine canyons are mostly found in continental slope.

  4. The submarine flat topped mountains are called guyots.

Which of the statements given above are correct?

  1. 1, 2. 3 and 4

  2. 1, 2 and 4

  3. 1, 3 and 4

  4. 2 and 3
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Statement 1 is correct - fold mountains running parallel to coastlines typically have narrow or absent continental shelves (like the Andes). Statement 2 is incorrect - continental shelf depth ranges from 0-200m, averaging 130m, not exactly 100m. Statement 3 is correct - submarine canyons are indeed common on continental slopes. Statement 4 is correct - guyots are flat-topped seamounts (submarine mountains).

Multiple choice

The coastline formed by the submergence of mountain ridges running parallel to the coast is known as :

  1. Dalmation coast

  2. Ria coast

  3. Fiord coast

  4. Haff caost
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Dalmatian coast is formed when parallel mountain ridges running along the coast are submerged, creating longitudinal islands and channels. This coastline type is named after the Dalmatian region of Croatia and is characterized by islands parallel to the mainland coast.

Multiple choice

Consider the following statements: Salinity of water in the equatorial ocean decreases because

  1. large rivers like Amazon and Congo enter into the sea
  2. evaporation is less.
  3. waters from Arctic and Antarctic mix with waters of equator.
  4. of heavy rainfall.

Which of these statements are correct?

  1. 1 and 2

  2. 3 and 4

  3. 1 and 3

  4. 1 and 4
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Equatorial ocean salinity decreases primarily because: (1) large rivers like Amazon and Congo discharge tremendous freshwater volume, and (4) heavy rainfall directly dilutes surface waters. Statement 2 about evaporation is incorrect - evaporation is actually high in equatorial regions, which would increase salinity. Statement 3 about polar waters mixing is incorrect.

Multiple choice

Spring tide means

  1. Higher high tide, higher low tide

  2. Higher high tide, lower low tide

  3. Lower high tide, lower low tide

  4. Lower low tide, higher low tide
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Spring tides occur when the Sun, Moon, and Earth align during new moon or full moon phases, creating the greatest tidal range. This alignment produces both higher high tides and higher low tides than normal, as gravitational forces combine to maximize water movement.

Multiple choice

Consider the following statements

  1. Continental shelves are wider where high mountains area very close and parallel to the coast.
  2. Continental shelves are formed by prolonged deposition of detritus under sea water in those areas where sea conditions are calm.
  3. Extensive continental margins during the time of negative change of the sea level.
  4. Continental shelves are formed by the submergence of continental margins due to tilting of land towards sea.

Which of the above statements are correct?

  1. 1, 2 and 3

  2. 2, 3 and 4

  3. 1, 3 and 4

  4. 1, 2 and 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Statements 2, 3, and 4 are correct: shelves form by prolonged deposition under calm conditions (2), can expand during negative sea level changes (3), and form through submergence due to land tilting (4). Statement 1 is incorrect because shelves are typically narrower where high mountains parallel the coast, not wider. Thus option B (2, 3, 4) is correct.

Multiple choice

Salinity in ocean water is decrease when

  1. evaporation is more

  2. wind velocity is high

  3. rainfall is heavy

  4. humidity is high
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ocean salinity decreases when freshwater input increases. Heavy rainfall (C) adds fresh water to oceans, diluting salt content. High evaporation increases salinity by removing water while leaving salts behind. Wind velocity and humidity affect evaporation rates but don't directly decrease salinity like rainfall does.

Multiple choice

Which one of the following statements is not correct?

  1. Gulf with narrow fronts and wider rears experiences high tides.

  2. Tidal currents take place when a gulf is connected with the open sea by a narrow channel.

  3. Tidal bore occurs when a tide enters the row and shallow estuary of a river.

  4. The tidal nature of the mouth of the river Hooghly is of crucial importance to Kolkata as a port.
Reveal answer Fill a bubble to check yourself
D Correct answer
Multiple choice

Top layer of marine ecosystem possess

  1. planktons

  2. nektons

  3. both of the above

  4. neustons

  5. benthos
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The collection of minute or microscopic organisms that inhabit the surface layer of a body of water