Ch 14 -16 Quiz Review – Key
1. What are the main producers of food in the ocean? Photosynthetic organisms like plants, algae,
bacteria
2. What does the steep continental slope merge into where there are no trenches? The continental rise
3. Define thermocline and pycnocline. Thermocline is the layer of ocean water between about 300 and
1000 meters where there is a rapid change of temperature with depth (it gets colder). Pycnocline is the
layer of ocean water between about 300 and 1000 meters where there is a rapid change of density with
depth (it gets more dense).
4. What is turbulence? What does it do? Irregular movement of water, churning; it allows the longshore
current to move larger sand and gravel particles along the ocean bottom near the shore
5. Where do you find the lowest density seawater? Surface mixed zone
6. Describe the deepest parts of the ocean floor (include temperature, density, animal/plant life). Low
temperatures a few degrees above freezing, constant high-density water, animals live in constant
darkness
7. What term describes organisms that live on or in the ocean floor? benthos
8. What happens to waves when there is refraction in bays? They erode headlands.
9. Describe the characteristics of a deep ocean trench. They are long narrow depressions; they form the
deepest parts of the ocean; they are sites where plates plunge back into the mantle.
10. Most ocean water is located in which zone? Deep zone
11. What is an upwelling? The rising of cold water from deeper layers to replace warmer surface water
12. List the Earth’s four main oceans from largest to smallest. Pacific, Atlantic, Indian, Arctic
13. What is plankton? Give an example. Organisms that drift with the ocean currents; algae
14. Are the ocean currents move toward the poles warm or cold? Or both? warm
15. What factors are used to divide the ocean into distinct marine life zones? Availability of sunlight,
distance from shore, and water depth
16. Which ocean has the greatest average depth? Pacific
17. What factors affect the density of seawater? Salinity and temperature
18. Which ocean zone is characterized by high water pressure, low temperatures, and no sunlight?
Abyssal zone
19. What is wave erosion? What landforms can be created by wave erosion? Erosion by waves; sea
arches and sea stacks
20. What part of the ocean are important mineral deposits associated with? Continental shelves
21. What is nekton? Give an example. Organisms capable of moving independently of the ocean currents;
fishies
22. What technology do scientists use to measure ocean depth? sonar
23. Deep, steep-sided valleys that originate on the continental slope and may extend to the ocean basin
floor are called _____. Submarine canyons
24. Which part of the ocean is deepest? trenches
25. Which force is involved in the development of surface currents? friction
26. Describe the different types of ocean sediments. Terrigenous sediments originate on land from eroded
rocks. Biogenous sediments are shells and skeletons of marine animals and algae. Hydrogenous
sediments are minerals that crystallize directly from ocean water.
27. How do most gas hydrates form? Bacteria break down organic matter trapped in ocean-floor
sediments.
28. What does circular orbital motion refer to? Water particles and the transfer of energy
29. What are hydrothermal vents? Mineral-rich water, heated by newly formed ocean crust, that escapes
through cracks in the ocean floor
30. What processes decrease the salinity of seawater? Increase the salinity? Answer the same two
questions for density. Salinity will decrease because of precipitation, sea ice melting, icebergs melting,
and runoff. It will increase from evaporation and formation of sea ice. Density increases with an
increase in salinity and a decrease in temperature. It decreases with a decrease in salinity and an
increase in temperature.
31. What are submersibles and what can they do? They are small underwater crafts used for deep-sea
research; they collect data about areas of the ocean that were previously unreachable by humans, and
they can remain underwater for long periods of time.
32. When do waves begin to “feel bottom”? when water depth is equal to half the wavelength
33. What ocean currents are associated with downslope movements of dense sediments-rich water?
Turbidity currents
34. What factors affect ocean waves? They greater the wind speed is, the higher the wave; they can travel
long distances; they get their energy from the wind.
35. The vertical distance between trough and crest is called the _____. Wave height
36. What factors influence a region’s photosynthetic productivity? Nutrients and sunlight
37. What causes surface ocean currents to be deflected? The Coriolis Effect