Geography · Environmental Studies

Oceanography and Hydrology

1,673 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 relief features is defined as a low island found in the tropical oceans consisting of coral reefs surrounding a central depression?

  1. Seamount

  2. Guyot

  3. Submarine Canyon

  4. Atoll

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

Atoll is a low island found in the tropical oceans consisting of coral reefs surrounding a central depression. It may be a part of the sea (lagoon), or sometimes form enclosing body of fresh, brackish, or highly saline water.

Multiple choice

Sonar fitted in ships helps to find

  1. presence of oil in sea water

  2. presence of icebergs

  3. hotness of sea water

  4. coldness of sea water

  5. depth of sea water
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Sonar sends vibrations deep inside the sea, they touch the ground and return back and the time they take in returning back, helps in calculating the depth of the sea.

Multiple choice

The water that is evaporated from the oceans or seas again ____________ to form water and fills up the rivers and seas.

  1. condenses

  2. transpires

  3. evaporates

  4. precipitates

  5. photosynthesises
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Correct. The process through which evaporated water is converted back to water is called condensation. The water vapor present starts to condense to form tiny water droplets, these droplets float in the air and form cloud and fog and rain . The whole process is called water cycle.

Multiple choice

Which of the following statements is correct?

  1. The life cycle of aquatic organisms is called the water cycle.

  2. Our Earth is covered by three-fourths of water.

  3. A variety of salts, like magnesium and potassium, are present in saline water.

  4. Rain harvesting causes the problem of depleting the ground water.

  5. Ocean and sea water contains many dissolved salts and is beneficial for drinking, agriculture and domestic purposes.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Correct. A variety of salts, like sodium chloride, calcium, magnesium, and potassium are present in saline water.

Multiple choice

In the hydrosphere, ocean water unsuitable for human use is

  1. 92%

  2. 94%

  3. 96%

  4. 97%
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Of all water on Earth, about 97.5% is saline ocean water unsuitable for drinking or irrigation without desalination. Only about 2.5% is freshwater, and most of that is locked in glaciers or groundwater. This makes approximately 97% of ocean water unusable for direct human consumption.

Multiple choice

Directions: Complete the given paragraph by selecting the most appropriate answer from the given options and fill blank (11).

Tidal waves are ________ (9) sea waves known as tsunamis. They are often_________ (10), destroying entire towns. Tsunamis are caused by ________ (11) movements such as earthquakes, volcanic_________ (12), or landslides. They can reach speeds up to 450 miles per hour and a height of 100 feet.

  1. oceanic

  2. kaolin

  3. submarine
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The meaning of Option 3 is undersea.

Multiple choice

The consequence(s) of ocean acidification is/are

  1. decrease in the noise propagation
  2. over-population of shell creatures

  1. Only 1

  2. Only 2

  3. Both 1 and 2

  4. Neither 1 nor 2
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Ocean acidification is the decrease in the pH and increase in acidity of the Earth's oceans caused by the uptake of anthropogenic carbon dioxide (CO2) from the atmosphere. About a quarter of the carbon dioxide in the atmosphere goes into the oceans, where it forms carbonic acid. Statement 1 is wrong as ocean acidification allows sound to propagate, further increasing ocean noise and impacting animals that use sound for echolocation or communication. Statement 2 is wrong because when ocean pH falls, the concentration of carbonate ions get under saturated and structures made of calcium carbonate become vulnerable to dissolution. Species like shellfish and pteropods experience dissolution when exposed to elevated CO2. Hence, option '4' is correct.

Multiple choice

A stetch of land surrounded by water on three sides known as:

  1. Strait

  2. Delta

  3. Peninsula

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A peninsula is a landform surrounded by water on three sides and connected to mainland on the fourth. India itself is a peninsula (Deccan Peninsula). A strait is a narrow water passage, while a delta is formed by river deposition at a river's mouth.

Multiple choice

Which among the following statements does not characterise red tides?

  1. The occurrence of red tides may be natural or from human activities.

  2. Coastal water pollution can cause red tides.

  3. Iron-rich dust influx from large desert can cause red tides.

  4. Red tides are related to the movements of the tides.

  5. When the algae are present in high concentrations, the water appears to be discolored.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Red tides are unrelated to movements of the tides. They are not necessarily red and many have no discolouration at all.

Multiple choice

Percentage of salt in the sea water is

  1. 40 gr per kilo

  2. 50 gr per kilo

  3. 35 gr per kilo

  4. 25 gr per kilo
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Seawater contains approximately 3.5% salt by weight, which equals 35 grams per kilogram of seawater. This salinity level is consistent across most of Earth's oceans.

Multiple choice

Ocean surface currents follow clockwise circulatory paths in the northern parts of the Pacific and Atlantic oceans due to the

  1. convergence and divergence movements

  2. coriolis force

  3. density differences in sea water

  4. impact of prevailing winds
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Ocean surface currents in the northern hemisphere form clockwise rotating systems called gyres, primarily driven by wind patterns and the Coriolis effect. However, the question specifically asks for the primary cause. The Coriolis force causes the deflection that creates the circular pattern, but it is the prevailing winds (trade winds and westerlies) that provide the initial energy and momentum to the surface currents. The impact of prevailing winds is the more direct and immediate cause of both the movement and the clockwise direction (combined with Coriolis). Options A, B, and C are incorrect because: convergence/divergence is a result not the cause, density differences drive deep ocean currents not surface ones, and while Coriolis causes the rotation, winds drive the movement itself.

Multiple choice

Which of the given statements is/are correct in reference to Law of the Sea Treaty?

Consider the following statements:

1. Sea baseline limit is based on territorial waters, archipelagic waters, contiguous zones, continental shelves and EEZs.

2. High seas include the water column beyond the exclusive economic zone (EEZ).

3. United States has extended U.S. territorial waters from three nautical miles to twelve nautical miles for national security purpose.

  1. Only 1

  2. Only 2

  3. Only 3

  4. All of the above

  5. None of the above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This statement is correct. High seas is the term used for water column beyond the Exclusive Economic Zone (EEZ) or beyond the territorial sea where no EEZ has been declared.