ocean prelim 2 answers

1. With regard to the global carbon cycle, how does the magnitude of CO2 sequestered by the global ocean through photosynthesis and, separately, the magnitude of CO2 released by the global ocean through respiration compare to the magnitude of CO2 emitted by humans through fossil-fuel burning?
   a. Ocean respiration and ocean photosynthesis are each much smaller than human emissions.
   b. Ocean respiration and ocean photosynthesis are each about the same as human emissions.
   c. Ocean respiration and ocean photosynthesis are each much larger than human emissions.

c. Ocean respiration and ocean photosynthesis are each much larger than human emissions.

2. Net Primary Production and Photosynthesis are equivalent terms.
   a. True
   b. False

b. False

3. Which light level produces zero Net Primary Production?
   a. Photo-Inhibited Light Level
   b. Light-limited Level
   c. Compensation Light Level
   d. Light-Saturation Level

c. Compensation Light Level

4. Which type of phytoplankton has the growth advantage at low nutrient concentration?
   a. Small cells
   b. Large cells

a. Small cells

5. Which nutrient limits the growth of phytoplankton in the Southern Ocean?
   a. Nitrogen
   b. Phosphorous
   c. Magnesium
   d. Iron

d. Iron

6. Why is primary production in the Eastern Equatorial Pacific higher than in the Western Equatorial Pacific?
   a. The Trade Winds are stronger in the East, and this drives stronger equatorial divergence of the Ekman Layer.
   b. The thermocline is shallower in the Eastern Equatorial Pacific.
   c. Coriolis force is stronger in the Eastern Equatorial Pacific.
   d. Walker Circulation is stronger in the Eastern Equatorial Pacific.

b. The thermocline is shallower in the Eastern Equatorial Pacific.

7. Why do coastal upwelling regions experience seasonal increases in primary production?
   a. Because higher sun angles and longer day lengths in summer stimulate the growth of phytoplankton.
   b. Because the winds driving upwelling is seasonally variable.
   c. Because iron-rich dust blowing off continents and into the coastal environment is seasonally variable.
   d. Because river runoff increases during springtime and enhances the delivery of nutrients to the coastal environment.

b. Because the winds driving upwelling is seasonally variable.

8. Where is the critical depth located relative to the compensation depth?
   a. Shallower
   b. Deeper
   c. They are found at the same depth

b. Deeper

9. If phytoplankton mix a little bit below the compensation depth, then net primary production averaged over the course of a day will be negative.
   a. True
   b. False

b. False

10. Why should you thank the ocean for every other breath you take?
    a. Because primary production in the ocean constitutes about half of global primary production.
    b. Because half of all living biomass on Earth resides in the ocean.
    c. Because half of all the CO2 emitted since the beginning of the Industrial Era has been taken up by the ocean.
    d. Because the ocean produces half of all the global CO2 each year.

a. Because primary production in the ocean constitutes about half of global primary production.

11. Which region comprises most of the global ocean primary production
    a. Open ocean
    b. Coastal upwelling

a. Open ocean

12. What do oceanographers mean when they say that pelagic ecosystems are strongly size structured?
    a. They mean larger animals will consume any and all animals that have a smaller body size.
    b. They mean larger animals will consume any and all animals with a similar body size.
    c. They mean that body size is the dominant factor that determines what trophic level any given animal species will reside in.
    d. They mean as a general rule, pelagic animal body shape is elongated in structure to allow for more efficient movement through the fluid environment.

c. They mean that body size is the dominant factor that determines what trophic level any given animal species will reside in.

13. What is the level of Exploitation Efficiency for the case of small grazers feeding on small phytoplankton in tropical regions?
    a. Exploitation Efficiency is Low
    b. Exploitation Efficiency is Medium
    c. Exploitation Efficiency is High

c. Exploitation Efficiency is High

14. Given a Trophic Transfer Efficiency of 10%, how many units of fish would be produced each year if you started with 1000 units of phytoplankton?
    phytoplankton > zooplankton > fish
    a. 1000
    b. 100
    c. 10
    d. 1

c. 10

15. Where is overall production of harvestable fish greatest?
    a. Open Ocean Region
    b. Coastal Region
    c. Equatorial Region
    d. Arctic Region
    e. Southern Ocean Region

b. Coastal Region

16. What do heterotrophic bacteria use for their source of energy and carbon?
    a. Dissolved organic matter.
    b. Sunlight and carbon dioxide.
    c. Predation on viruses that are 1/10 the size of heterotrophic bacteria.

a. Dissolved organic matter.

17. Prochlorococcus contributes to more than a quarter of the total global ocean primary production.
    a. True
    b. False

a. True

18. Where does the Biological Carbon Pump operate most efficiently?
    a. In Eutrophic regions
    b. In Oligotrophic regions
    c. In Mesotrophic regions
    d. In Anoxic conditions

a. In Eutrophic regions

19. What factor or factors determines where a given species resides in the rocky intertidal?
    a. Ability to withstand desiccation
    b. Ability to compete for space
    c. Ability to avoid predation
    d. All of the above

d. All of the above

20. What happens to the level of biodiversity in the rocky intertidal region when the starfish Pisaster is removed?
    a. Biodiversity increases
    b. Biodiversity decreases
    c. Biodiversity stays about the same

b. Biodiversity decreases

21. What is meant by the term Trophic Cascade?
    a. It describes the additive impact of greater and greater decrease in the abundance of organisms in adjacent trophic levels.
    b. It describes the alternating decrease-increase-decrease in the abundance of organisms in adjacent trophic levels.

b. It describes the alternating decrease-increase-decrease in the abundance of organisms in adjacent trophic levels.

22. What is responsible for the massive declines in kelp forests off the California coast over the past decade?
    a. Over harvesting of kelp for animal feed in industrial agriculture.
    b. A large sea otter increase resulting from new marine protections
    c. Sunflower starfish decline due to bacterial disease
    d. Sea urchin declines due to over harvesting

c. Sunflower starfish decline due to bacterial disease

23. What percentage of a coral’s nutrition comes from its Zooxanthellae symbionts?
    a. 10%-20%
    b. 30%-60%
    c. 60%-90%
    d. 100%

c. 60%-90%

24. What resource is in short supply in coral reefs and under stiff competition with other coral species?
    a. Light
    b. Nutrients
    c. Space
    d. Zooplankton Prey

c. Space

25. What happens when coral reefs are overfished?
    a. The decline in fish leads to an increase in sea urchins and a decrease in coral cover.
    b. It leads to a large increase in zooplankton … causes coral to expel Zooxanthellae.
    c. It reduces herbivory on macro algae and allows the macro algae to overgrow and smother coral species.
    d. Overfishing reduces biodiversity, but corals are not affected.

c. It reduces herbivory on macro algae and allows the macro algae to overgrow and smother coral species.

26. How much coral cover has already been killed off over the past 150 years?
    a. <10% b. 50% c. 90% d. >99%

b. 50%

27. What percentage of corals will be lost if global warming reaches 2 ºC?
    a. <10% b. 30%-50% c. 70%-90% d. >99%

d. >99%

28. What unique skeletal feature is used to connect all of the transitional fossils between Pakicetus and modern whales?
    a. Skull shape
    b. Hooved limbs
    c. Ear bone
    d. Dental pattern

c. Ear bone

29. What time of year should you visit Hawaii if you wanted to see humpback whales?
    a. Summer
    b. Winter

b. Winter

30. Which of the following noise sources did Professor Chris Clark express the most concern for impacting whale population success?
    a. Navy Sonar.
    b. Commercial shipping.
    c. Offshore oil exploration.

b. Commercial shipping.

31. Off-shore oil exploration uses air guns… How often do these air guns blast noise into the ocean?
    a. Once a day for several months
    b. Once an hour for several months
    c. Once every 10 minutes for several months
    d. Once every 10 seconds for several months

d. Once every 10 seconds for several months

32. Whether or not whales can be humanely killed is one ethical issue… What was the other ethical issue discussed in class?
    a. Whaling puts sailors at great risk.
    b. Extraction of a common public resource from the ocean for commercial profit.
    c. Hunting species listed as vulnerable or endangered with extinction.
    d. Only a small fraction of the whale is marketed and most discarded.

b. The extraction of a common public resource from the ocean for commercial profit.

33. What property of water allows it to form hydrogen bonds with adjacent water molecules?
    a. Triangular molecular shape
    b. Linear molecular shape
    c. Polar charge distribution (slightly + on one side, slightly − on the other)
    d. Ability to covalently share electrons with adjacent molecules.

c. The polar charge distribution with one side slightly positive and the other slightly negative.

34. What two opposing molecular forces/energies determine the three phases of water?
    a. H-bonds and Hydro-elastic energy
    b. Covalent bonds and Hydrogen bonds
    c. Strong nuclear forces and Weak electrostatic forces
    d. Strong nuclear forces and Weak nuclear forces
    e. H-bonds and Thermal-Kinetic energy

e. H-bonds and Thermal-Kinetic energy

35. When heat is added to the surface ocean, temperature rises less than on land/air. Why?
    a. Heat is diluted by mixing through the entire water column to the seafloor.
    b. Water has an exceptionally large specific heat capacity.
    c. Water has an exceptionally small specific heat capacity.
    d. Evaporation removes much of the added heat energy.
    e. Conveyor belt removes excess heat to high latitudes quickly.

b. Water has an exceptionally large specific heat capacity.

36. When water vapor is transported by winds it transports heat stored as latent heat that becomes sensible heat when it condenses to rain elsewhere.
    a. True
    b. False

a. True

37. What determines surface ocean salinity for a given geographic location?
    a. Amount of Precipitation
    b. Amount of Evaporation
    c. Difference between Evaporation and Precipitation
    d. Difference between river salt addition and precipitation dilution

c. The difference between Evaporation and Precipitation in the region.

38. Where is surface ocean salinity lowest?
    a. Subpolar North Atlantic
    b. Subpolar North Pacific
    c. Atlantic Subtropical Gyres
    d. Pacific Subtropical Gyres

b. Subpolar North Pacific

39. What happens to nitrate and phosphate in deep ocean waters (4000 m) as deep waters move from the North Atlantic to the North Pacific?
    a. The concentration increases
    b. The concentration decreases
    c. The concentration stays roughly constant

a. The concentration increases

40. Why is oxygen high in the upper layer of the ocean?
    a. Diffusion of atmospheric oxygen into the ocean.
    b. Photosynthesis
    c. Both a and b

c. Both a and b

41. What causes an oxygen minimum zone to form just below the sunlit layer?
    a. Rapid downward mixing just below the minimum zone.
    b. High microbial respiration fueled by dead organic material raining down.
    c. Ekman transport of low oxygen water from winds.
    d. None of the above

b. A high level of microbial respiration, fueled by dead organic material raining down.

42. Why does deep-ocean oxygen (4000 m) decrease from the North Atlantic to the North Pacific?
    a. Lateral mixing dilutes oxygen.
    b. Oxygen reacts with water to form dioxygen monoxide.
    c. Microbial respiration along the ~2000-year journey.
    d. Oxygen radioactively decays.

c. Microbial respiration along the 2000-year journey from Atlantic to

Pacific

43. Why is CO2 low in the surface ocean?
    a. Downward diffusion of dissolved CO2 to the deep ocean.
    b. Upward diffusion of CO2 to the atmosphere.
    c. Photosynthesis in the surface ocean
    d. Respiration in the surface ocean

c. Photosynthesis in the surface ocean

44. How much of cumulative fossil-fuel CO2 has the ocean taken up?
    a. About 10%
    b. About 30%
    c. About 60%
    d. About 90%

b. About 30%

45. The ocean surface is 60% more acidic today relative to the pre-industrial level.
    a. True
    b. False

b. False

46. What will happen to surface-ocean acidity if you bring deep ocean water to the surface?
    a. Acidity will increase.
    b. Acidity will decrease.
    c. Acidity will stay about the same.

a. Acidity of the surface ocean will increase.

47. Oyster aquaculture on the west coast of the United States will begin to be impacted by ocean acidification within two to three decades.
    a. True
    b. False

b. False

48. Why are polar seas especially vulnerable to ocean acidification?
    a. Surface ocean salinity is lower in polar regions.
    b. Cold water can absorb more CO2 than warm water.
    c. Western boundary currents transport additional CO2 to polar regions.
    d. Convergence into polar regions concentrates CO2.

b. Cold water can absorb more CO2 than warm water.

49. With “business-as-usual” emissions, how soon will polar seas become corrosive to calcium carbonate shells used by plankton?
    a. 2 to 3 years
    b. 20 to 30 years
    c. By the end of the century (2100)

b. 20 to 30 years

50. When we finally stop burning fossil carbon and emitting CO2, ocean acidity will remain elevated for 10,000 years.
    a. True
    b. False

a. True
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