The World Ocean

Practice exam questions written by Timothy H. Heaton,
Professor of Earth Sciences, University of South Dakota

Click the circle by an answer with the mouse, then click on the Submit button to get a response. You will be told if your answer is correct or not and will be given some comments.

  1. What is the largest ocean on earth?
    Arctic.
    Atlantic.
    Indian.
    Pacific.

  2. Which ocean is increasing most in size over time?
    Arctic.
    Atlantic.
    Indian.
    Pacific.

  3. Which ocean is decreasing most in size over time?
    Arctic.
    Atlantic.
    Indian.
    Pacific.

  4. Which ocean is a remnant of the universal ocean Panthalassa?
    Arctic.
    Atlantic.
    Indian.
    Pacific.

  5. Where are the major ocean basins most connected to one another such that substantial water is exchanged between them?
    Around Antarctica.
    At the North Pole.
    Near the equator.
    Throughout the northern hemisphere.
    Throughout the southern hemisphere.

  6. How deep are the ocean basins on average?
    4,000 feet.
    4,000 km.
    4,000 meters.
    4,000 miles.

  7. What are the deepest parts of the ocean?
    In ocean sinkholes.
    In random depressions.
    Near the continents.
    The middle of the ocean basins.
    In trenches formed by subduction zones.

  8. What is the most abundant dissolved ion in the oceans?
    Calcium.
    Chlorine.
    Magnesium.
    Sodium.
    Sulfate.

  9. What value is salinity usually measured in?
    Calories.
    Ounces.
    Parts per million.
    Parts per thousand.
    Percent.

  10. What is a typical salinity value for the oceans?
    5 o/oo.
    10 o/oo.
    15 o/oo.
    25 o/oo.
    35 o/oo.

  11. Where does ocean salinity tend to be the highest?
    At desert latitudes.
    In deeper water.
    Near the equator.
    Near the poles.
    Near river mouths.

  12. What is the thermocline?
    The coldest part of the ocean.
    The hottest part of the ocean.
    The zone of greatest heat loss.
    The zone of greatest temperature change.
    The zone of greatest salinity change.

  13. What primarily drives the surface ocean currents?
    Coriolis forces.
    Deep sea vents.
    Density differences between water bodies.
    Rotation of the earth.
    Winds.

  14. What primarily drives the deep ocean currents?
    Coriolis forces.
    Deep sea vents.
    Density differences between water bodies.
    Rotation of the earth.
    Winds.

  15. What consequence does the coriolis effect have, relative to the Earth's surface, on masses of air or water that are changing latitude?
    The results are unpredictable; currents can veer right or left in either hemisphere.
    They veer to the left in the northern hemisphere and to the right in the southern hemisphere.
    They veer to the right in the northern hemisphere and to the left in the southern hemisphere.
    They veer to the right in both hemispheres.
    They veer to the left in both hemispheres.

  16. What phenomenon does the Coriolis effect arise from?
    Curvature of the earth's surface.
    Rotation of the earth around its axis.
    Rotation of the earth around the sun.
    Effect of winds high in the atmosphere.
    Motion of the oceans in their basins.

  17. In most ocean basins, how does surface water circulate?
    It circulates counterclockwise (CCW) in both hemispheres.
    It circulates clockwise (CW) in both hemispheres.
    In circulates CCW in the northern hemisphere and CW in the southern hemisphere.
    In circulates CW in the northern hemisphere and CCW in the southern hemisphere.
    There is no general pattern, and each ocean behaves completely differently.

  18. Where does deep upwelling usually occur?
    In the middle of the oceans.
    Near continents.
    Near the equator.
    Near the poles.
    Near trenches.

  19. Under what conditions does coastal upwelling commonly occur?
    Only where biotic productivity is high enough to sustain it.
    Only on the eastern coasts of continents.
    Only on the western coasts of continents.
    Where winds blow toward shore or Ekman flow carries surface water toward shore.
    Where winds blow away from shore or Ekman flow carries surface water away from shore.

  20. As waves move along the surface of the water, what do water particles do?
    They move back and forth in a direction parallel to wave motion.
    They move back and forth in a direction perpendicular to wave motion.
    They move along the crests of waves and can travel thousands of miles.
    They oscillate in circles whose diameters decrease with depth.
    They remain almost entirely motionless.

  21. How deep in water do surface waves cause particle motion?
    Half the wave height.
    Exactly the wave height.
    Twice the wave height.
    Four times the wave height.
    Half the wave length.

  22. What determines wave speed in the open oceans?
    Wave height.
    Wave length.
    Wind velocity.
    All of the above.
    Wave speed is constant regardless of these factors.

  23. What is Surf?
    Capillary waves generated by light winds.
    Fully-developed waves generated by strong winds.
    Waves that grow larger the farther they travel.
    Waves moving out of the generating area.
    Waves moving into shallow water and eventually breaking.

  24. What is Swell?
    Capillary waves generated by light winds.
    Fully-developed waves generated by strong winds.
    Waves that grow larger the farther they travel.
    Waves moving out of the generating area.
    Waves moving into shallow water and eventually breaking.

  25. What happens to waves when they reach shallow water?
    They continue unabated.
    They slow down.
    They speed up.
    They veer to the right.
    They veer to the left.

  26. When waves reach an irregular coastline, how is their energy distributed?
    It is equally distributed between bays and headlands.
    It is focused on bays and cuts them deeper.
    It is focused on headlands and erodes them back.
    It is reflected back to sea.

  27. What effect does wave energy tend to have on a coastline?
    It makes the coast more straight.
    It makes the coast more jagged.

  28. Which of the following waves generally have the longest wavelength?
    Capillary waves.
    Gravity waves.
    Internal waves.
    Tides.
    Tsunami.

  29. Which of the following waves are generated by earthquakes and can devastate coastal communities?
    Capillary waves.
    Gravity waves.
    Internal waves.
    Tides.
    Tsunami.

  30. How many bulges are generated by the tide-raising force on the earth at one time?
    1.
    2.
    3.
    4.

  31. How many high tides occur per day in most coastal areas?
    1.
    2.
    3.
    4.

  32. What are tides of large amplitude that occur every two weeks called?
    Diurnal tides.
    Equatorial tides.
    Neap tides.
    Semidiurnal tides.
    Spring tides.

  33. What is the relative tidal force of the sun and moon?
    The sun and moon exert equal tidal forces on the earth.
    The sun exerts twice the tidal force of the moon.
    The sun exerts three times the tidal force of the moon.
    The moon exerts twice the tidal force of the sun.
    The moon exerts three times the tidal force of the sun.

  34. Where are the greatest tidal ranges on earth found?
    In large lakes like Lake Ontario.
    In narrow bays like the Bay of Fundy.
    In polar oceans like the Arctic Ocean.
    In the largest oceans, particularly the Pacific.
    In wide bays like the North Sea.

Please report any problems or errors to Dr. Heaton.