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 of the following could replace 'turning' as used in the passage?

Directions: Read the following passage carefully and select the most suitable option according to the corresponding number in the passage.

The Hydrosphere is an imaginary (1) sphere. However, its importance is not imaginary. The hydrosphere contains all the water that is above, below, or upon the surface of the earth. It also includes (2) the water inside plants and animals. The larger part of the earth's hydrosphere is salt water. The water cycle pureifys (3) the atmosphere and surface water by removing (4) pollutants. It (5) supplies usable water to living things on land. It does so by purifying the saltwater of the oceans and by turning (6) it into fresh water. All life thus depends upon an "active hydrosphere." That means an intact or undamaged hydrosphere with a running (7) water cycle. Since all living things use water inside their bodies, an active hydrosphere and life travel hand in hand (8).

  1. fixing

  2. converting

  3. rotating

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

The passage discusses how the water cycle transforms saltwater into freshwater. Converting means changing from one form, state, or function to another, which perfectly describes the transformation of saltwater to fresh water through evaporation and precipitation. The other options don't capture this transformative process.

Multiple choice

Which of the following factors modify ocean currents?

  1. Rotation of Earth
  2. Air pressure and wind
  3. Ocean water density
  4. Revolution of Earth

  1. 1 and 2

  2. 1, 2 and 3

  3. 1 and 4

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

Ocean currents are driven by three primary factors: Earth's rotation creates the Coriolis effect, wind patterns move surface water, and differences in water density (from temperature and salinity variations) cause vertical movement. Earth's revolution around the sun creates seasons but does not directly cause ocean currents. Therefore, only factors 1, 2, and 3 are correct.

Multiple choice

What is Continental Shelf?

  1. Mountain ranges that edge a continent

  2. The raised land on a continent's edge

  3. The land that gently slopes and extends to the steeper descent of the continent before sharply sloping to form the sea floor.

  4. A plateau in the centre of a continent
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

A continental shelf is the submerged edge of a continent that gradually slopes from the shoreline to a drop-off point (usually around 200 meters deep), after which the sea floor slopes steeply down to the abyssal plain. It is NOT a mountain range, raised land, or plateau - those are terrestrial features. Option C accurately describes the gentle slope followed by steep descent characteristic of continental shelves.

Multiple choice

The average salinity of sea water is

  1. 35/1

  2. 27/1

  3. 80/1

  4. 42/1
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The standard average salinity of seawater is 35 parts per thousand (ppt), often expressed as 35/1 or 35‰. This means 35 grams of salt per kilogram of seawater. The other values (27, 80, 42) don't match the established scientific standard for ocean salinity.

Multiple choice

Sea tides are caused by

  1. revolution of Earth

  2. rotation of Earth

  3. combined effects of gravitational forces exerted by moon, sun and rotation of Earth

  4. wind over the ocean

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

Tides are the rise and fall of sea level caused by the combined effects of gravitational forces exerted by the moon, sun and rotation of Earth.

Multiple choice

What would happen to oceanic water if the moon comes nearer to the earth?

  1. Fall of temperature of oceanic water

  2. Stopping of oceanic currents

  3. Rise of the sea level

  4. Increase in the height of oceanic tides
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

If the Moon came closer to Earth, the gravitational pull on oceanic water would increase, causing higher tides. Tidal force is inversely proportional to the cube of distance, so a smaller distance means significantly stronger tidal effects. The temperature change (A), stopping of currents (B), and general sea level rise (C) are not direct consequences of the Moon's distance.

Multiple choice

We generally measure the depth of the sea in

  1. feet

  2. fathoms

  3. metres

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

Sea depth is traditionally measured in fathoms in maritime navigation. One fathom equals 6 feet (approximately 1.83 meters). While meters are also used in modern contexts, fathoms remain the standard nautical unit for depth measurement on navigational charts. Feet and nautical miles are used for distance, not depth.

Multiple choice

What is an Isthmus?

  1. It is a circular or horse-shoe shaped coral reef surrounding a lagoon either having an island or submerged plateau in it.

  2. It is a narrow passage of water connecting two seas or two large areas of water.

  3. It is a narrow strip of land joining two large areas of land that would otherwise be separated by water.

  4. It is a shallow stretch of water separated completely or partly from the sea by a narrow strip of land.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Isthmus

Multiple choice

Consider the following regions:

  1. Gulf of Khambat
  2. Gulf of Kachchh
  3. Sunderbans

The correct sequence of these regions in the descending order of their tidal energy potential is

  1. 1, 2, 3

  2. 3, 2, 1

  3. 3, 1, 2

  4. 1, 3, 2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The Gulf of Khambat has the highest tidal energy potential due to its unique geography and extreme tidal range (up to 11 meters). Gulf of Kachchh ranks second with significant tidal potential. Sunderbans has lower tidal energy potential compared to these two gulfs. The correct descending order is Gulf of Khambat > Gulf of Kachchh > Sunderbans.

Multiple choice

Consider the following facts about marine habitats:

  1. Neritic zone is the coastal waters extending upto continental shelf, different from the littoral zone.
  2. The benthic zone is the ecological region at the lowest level of a body of water.

Which of the above given facts is/are true?

  1. Only 1

  2. Only 2

  3. Both 1 and 2

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

The neritic zone, also called coastal waters, the coastal ocean or the sublittoral zone, is the part of the ocean extending from the low tide mark to the edge of the continental shelf, with a relatively shallow depth extending to about 200 metres (110 fathoms or 667 feet). The neritic zone has generally well-oxygenated water, low water pressure, and relatively stable temperature and salinity levels. The benthic zone is the ecological region at the lowest level of a body of water such as an ocean or a lake, including the sediment surface and some sub-surface layers. Organisms living in this zone are called benthos. For example, the benthic invertebrate community, including crustaceans and polychaetes.

Multiple choice

Consider the following facts:

  1. The Great Pacific Garbage Patch is so huge that it is visible through satellite imagery.
  2. Bound by the North Pacific Gyre, its position is almost stationary.
  3. The patch is characterized by exceptionally high concentration of pelagic plastics, which have been known to cause deaths of turtles and sea birds.

Which of the above are true?

  1. Both 1 and 2

  2. Both 2 and 3

  3. Both 1 and 3

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

The Great Pacific garbage patch, also described as the Pacific trash vortex, is a gyre of marine debris in the central North Pacific Ocean located roughly between 135°W to 155°W and 35°N and 42°N. The patch is characterized by exceptionally high concentrations of pelagic plastics, chemical sludge and other debris that have been trapped by the currents of the North Pacific Gyre. The garbage patch occupies a large and relatively stationary region of the North Pacific Ocean bound by the North Pacific Gyre (a remote area commonly referred to as the horse latitudes).

Multiple choice

The most striking set of characteristic of the deep sea includes

  1. high temperature, low pressure and high oxygen level

  2. low temperature, low pressure and low oxygen level

  3. high temperature, high pressure and high oxygen level

  4. low temperature, high pressure and low oxygen level
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The most striking set of characteristic of the deep sea includes: low temperature, high pressure and low oxygen level. Deep sea is the lowest layer in ocean. No light enters this region and the maximum organisms that live there depend for sustenance on falling organic matter formed in the photic zone.