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

The layer of the water in the oceans and lakes that separates the warmer surface layer from the deeper colder layer is called:

  1. epilimnion

  2. hypolimnion

  3. thermocline

  4. hypothermia
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The thermocline is the transition layer in a body of water where the temperature changes more rapidly with depth than it does in the layers above or below. It effectively separates the warm, well-mixed surface layer from the much colder deep-water layer.

Multiple choice

Radiolarian oozes occur in the depths of

  1. 600 to 1200 fathoms

  2. 1500 to 2000 fathoms

  3. 2000 to 5000 fathoms

  4. 5000 to 6000 fathoms
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Radiolarian oozes are siliceous pelagic sediments found in deep ocean basins. They typically occur at depths between 2000 and 5000 fathoms, where the dissolution of calcium carbonate allows these silica-based remains to accumulate.

Multiple choice

Consider the following conditions:1. Anticyclone conditions with static air and high temperature 2. Cyclonic conditions with unstable air 3. High precipitation with low evaporation4. Low precipitation with high evaporation.High salinity of ocean water is associated with:

  1. 1 and 4

  2. 2 and3

  3. 1 and 3

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

High salinity is caused by high evaporation and low freshwater input. Anticyclonic conditions (high pressure and temperature) promote evaporation, while low precipitation ensures that the salt concentration remains high.

Multiple choice

The average salinity of the ocean water is-

  1. 2.5%

  2. 3.0%

  3. 3.5%

  4. 4.0%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The average salinity of ocean water is approximately 35 parts per thousand, which is equivalent to 3.5 percent. This means that for every 1,000 grams of seawater, there are about 35 grams of dissolved salts. Salinity can vary slightly depending on evaporation rates and freshwater input from rivers.

Multiple choice

The coral reef which is circular or elliptical in shape an enclose a lagoon is called

  1. A barrier

  2. An atoll

  3. A coral dune

  4. A coral fringe
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

An atoll is a ring-shaped coral reef, island, or series of islets that surrounds a body of water called a lagoon. They typically form when a coral reef grows around a volcanic island that eventually subsides or sinks beneath the ocean surface. Fringing reefs and barrier reefs are different structures that do not fully enclose a central lagoon in this circular fashion.

Multiple choice

What percentage of Earth's surface area is covered by water?

  1. 71%

  2. 20%

  3. 15%

  4. 2%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Approximately 71% of the Earth's surface is covered by water, primarily in the form of oceans. The remaining 29% consists of continents and islands. This high percentage of water is why Earth is often referred to as the 'Blue Planet'.

Multiple choice

Directions: In this question, the first and the last (correctly ordered) sentences of a passage are numbered 1 and 6. The rest of the passage is split into four parts named B, C, D and E. These four parts are not given in the proper order. Choose the correct combination among the four alternatives given.

  1. Coral reefs are diverse underwater ecosystems held together by calcium carbonate structures secreted by corals. B. The polyps belong to a group of animals known as Cnidaria, which also includes sea anemones and jellyfish. C. Coral reefs are built by colonies of tiny animals found in marine waters that contain few nutrients. D. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. E. Unlike sea anemones, corals secrete hard carbonate exoskeletons, which support and protect the coral polyps.
  2. Reefs grow best in warm, shallow, clear, sunny and agitated waters.

  1. BEDC

  2. DBCE

  3. CDBE

  4. EBCD
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

‘Structures’ in 1 and ‘built’ in C link the sentences 1 and C. Introduction of 'polyps' in D links it with B and 'anemones' in B links it with E. Hence, we get the DBE link.

Multiple choice

What is the average salinity in ocean water?

  1. 3.5%

  2. 4.5%

  3. 8.5%

  4. 5.5%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The average salinity of ocean water is approximately 35 parts per thousand, which translates to 3.5 percent. This salinity is mainly due to dissolved salts, primarily sodium chloride. Salinity can vary depending on evaporation rates and freshwater influx from rivers.

Multiple choice

' Breakers' is another word for

  1. surf

  2. trough

  3. crest

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In oceanography, breakers are waves that have become unstable and collapse or 'break' as they approach the shore, forming the surf.

Multiple choice

Which of the following statements is/are false?

a. Some animals like sponges, corals and sea anemones do not move from place to place. b. The movement of a plant or its part towards the soil is called as geotropic movement. c. The period during which bacteria complete their life cycle is very long.

  1. Only a

  2. Only a and b

  3. Only b

  4. Only b and c

  5. Only c
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The period during which a bacterium completes its life cycle is very short. It is not more than 20 minutes.

Multiple choice

Oozes are associated with

  1. volcanic deposits

  2. terrigenous deposits

  3. pelagic deposits

  4. coral reefs
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Oozes are deep-sea sediments composed of at least 30 percent skeletal remains of microscopic organisms. They are classified as pelagic deposits, which accumulate on the deep ocean floor.

Multiple choice

Mangroves grow in the

  1. Oceans

  2. Inter-tidal zones

  3. Land

  4. Rivers
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Mangroves are specifically adapted to grow in inter-tidal zones, where they are periodically submerged by tides.