Final Previous Prelims

Question 1

What kind of tectonic process takes place in deep-sea trenches?

Answer 1

b. This is where ocean crust continuously sinks back into the mantle.

Question 2

How much of the total heat energy that has been trapped in the earth system by human added greenhouse gases has accumulated in the ocean? a. Less that 10% b. 32% c. 72% d. Greater than 90%

Answer 2

d. Greater than 90%

Question 3

3. What did Professor Greene propose as the key factor that may have setup the conditions that led to super storm Sandy striking New York and New Jersey with such explosive force? a. Warmer than normal surface ocean temperatures in the Atlantic due to global warming. b. A combination of a strong Pacific El Nino and a strong positive phase in the North Atlantic Oscillation. c. Loss of Arctic ice cover. d. Much of the destruction was associated with weak building designs that did not anticipate such high winds and flooding

Answer 3

c. Loss of Arctic ice cover.

Question 4

6. There is currently a massive amount of organic carbon locked away in frozen tundra soil. What is the big concern about the thawing of the tundra with regard to its impact on global warming? a. Microbial decomposition of the thawed organic material will eventually drive down oxygen levels, leading to hypoxic and anoxic conditions and creating massive dead zones in the arctic similar to what happens in the Gulf of Mexico. b. A runaway positive feedback loop will kick in and become unstoppable whereby methane gas will be released to the atmosphere as a byproduct of microbial decomposition of the thawed organic material, the planet will warm more, even more tundra will thaw, and even more microbial decomposition will occur, and so on.

Answer 4

b. A runaway positive feedback loop will kick in and become unstoppable whereby methane gas will be released to the atmosphere as a byproduct of microbial decomposition of the thawed organic material, the planet will warm more, even more tundra will thaw, and even more microbial decomposition will occur, and so on.

Question 5

7. Methane gas is produced when methane clathrates (frozen methane ice) found in continental shelf sediments undergo sublimation (a process of going directly from a solid to a gas) as a result of warming ocean conditions. How much global warming can occur (relative to preindustrial temperatures) before these clathrates start sublimating and methane gas starts to be produced? a. 0.8 °C b. 1.8 °C c. 2.0 °C d. 4.0 °C

Answer 5

1.8

Question 6

8. Do methane clathrates around the globe represent a large pool of methane? a. No, the methane pool is modest and would at most represent the equivalent of about 10 years of emissions at current emission rates. b. Yes, the methane pool is truly huge and would represent the equivalent of about 10,000 years of emissions at current emission rates

Answer 6

b. Yes, the methane pool is truly huge and would represent the equivalent of about 10,000 years of emissions at current emission rates

Question 7

10. Given that there is a fixed limit on the total amount of CO2 that can be added to the atmosphere before we would cross the 2°C warming threshold, when will we cross that limit with business as usual emission rates? a. By 2024 b. By 2034 c. By 2054 d. By 2100

Answer 7

b. By 2034

Question 8

11. Climate scientist James Hansen analyzed paleoclimate records of past atmospheric CO2 concentration and past sea level to create an equilibrium curve/graph showing how high sea level eventually equilibrates over time to a given CO2 concentration. Based on this equilibrium curve/graph he determined that to prevent catastrophic sea level rise we should limit CO2 in the atmosphere to: a. 280 ppm b. 350 ppm c. 380 ppm d. 450 ppm e. 550 ppm

Answer 8

B. 350 ppm

Question 9

12. Carbon Dioxide Reduction refers to the process of capturing carbon from the atmosphere and sequestering (storing) it deep underground. While this is the best geo-engineering solution, it is still largely in the proof-of-concept mode and not yet ready for widespread deployment. a. True b. False

Answer 9

True

Question 10

18. When oil companies explore for oil, they use air guns. Which of the sound sources below gives a comparable sound to that made by an air gun? a. Navy Sonar system b. Large commercial cargo ship c. Dynamite blast d. Large (10 km diameter) asteroid impact e. None of the above

Answer 10

C. Dynamite blast

Question 11

19. What analogy best describes the effect that increased commercial boat traffic has on whale populations? a. Eardrum-piercing noise that leads to deafness in whales. b. A noisy bar or restaurant that prevents social communication across appreciable distances. c. Loud discordant music that creates a strong sense of aggravation and agitation that often results in male whales becoming extremely aggressive. d. It closely mimics whale calls and leads many whales to leave the whale social group and follow the large commercial ships by thinking the ship is another whale calling them to follow.

Answer 11

b. A noisy bar or restaurant that prevents social communication across appreciable distances.

Question 12

20. How far does the noise travel from ships doing oil exploration on the continental shelf with seismic survey air guns? a. It can extend for hundreds of kilometers up and down the continental shelf. b. Most of the sound is attenuated within 3 nautical miles from the ship, which is why survey ships are required to have a spotter constantly on lookout for whales found within this range. c. Sound is attenuated very rapidly and does not travel more than 200 meters from its source.

Answer 12

a. It can extend for hundreds of kilometers up and down the continental shelf

Question 13

21. What percentage of top-predator fish, like tuna and swordfish, still remain in the ocean today relative to their abundance several decades ago? a. 10% remain b. 30% remain c. 60% remain d. 90% remain e. They are close to the same levels as before

Answer 13

a. 10% remain

Question 14

22. How much area of ocean seafloor is bottom-trawled each year relative to the amount of area lost to deforestation each year? a. Bottom trawling area is the same as deforestation area. b. Bottom trawling area is 100 times larger than deforestation area. c. Bottom trawling area is 150 times larger than deforestation area. d. Bottom trawling area is 300 times larger than deforestation area. e. Bottom trawling area is 600 times larger than deforestation area

Answer 14

c. Bottom trawling area is 150 times larger than deforestation area.

Question 15

23. How long are the lines and how many hooks are typically used on a longline fishing boat? a. About 1 km of line with close to a hundred baited hooks b. About 10 km of line with several hundred baited hooks c. About 100 km of line with several thousand baited hooks d. About 10,000 km with tens of thousands of baited hook

Answer 15

c. About 100 km of line with several thousand baited hooks

Question 16

25. What is the driving force behind the astonishing increase in shark finning over the past decade? a. Increases in sport fishing b. Increases in bycatch by long-line fishing c. Increased demand for shark fin soup d. Increased safety concerns for recreational swimmers e. Trophy hunting for fins

Answer 16

c. Increased demand for shark fin soup

Question 17

33. What is the main source of mercury to the global ocean? a. Factories that discharge water into the coastal ocean b. Runoff from roads c. Unregulated coal power generation of electricity d. Leaching from plastic pollution

Answer 17

c. Unregulated coal power generation of electricity

Question 18

36. How many coastal rivers and bays are moderately to severely degraded from nitrogen pollution? a. Less than 30% b. Greater than 50% c. Greater than 90% d. 100%

Answer 18

b. Greater than 50%

Question 19

39. It is known that a heavy meat diet puts a larger demand on the use of freshwater relative to a plant-based diet. What fraction of the major ground water basins (aquifers) around the world are currently under threat of being depleted? a. 1/3 b. 2/3 c. 3/3

Answer 19

a. 1/3

Question 20

40. According to the guest lecturer, Alison Tracy, what happens to coral reefs when exposed to increasing acidification conditions? a. Structural complexity decreases b. Species diversity declines c. Both and a and b

Answer 20

c. Both and a and b

Question 21

42. How might reefs be protected against future climate change? a. Selective breeding of more temperature resilient corals. b. Manipulation of their microbiome. c. Both a and b.

Answer 21

c. Both a and b.

Question 22

46. To Stay below 2°C (or 1.5°C) by end of the century, negative emissions are needed. a. True b. False

Answer 22

a. True

Question 23

47. Assuming that 2°C warming will keep human society safe is based on the fact that 2°C warmings happened in the geologic past and did not lead to strong positive climate feedbacks causing ruinous runaway climate. a. True b. False

Answer 23

a. True

Question 24

59. Seafloor spreading was thought to occur at mid-ocean ridges based on observations of: a. Extensional faulting along the ridge axis. b. Magnetic anomaly banding on either side of the ridge axis. c. The age of the crust on either side of the ridge axis. d. All of the above.

Answer 24

d. All of the above.

Question 25

60. What type of tectonic plate boundary is responsible for the formation of the Japanese Islands? a. Convergence of ocean crust with ocean crust b. Convergence of ocean crust with continental crust c. Divergence at a mid-ocean ridge d. Mantle hot spot

Answer 25

a. Convergence of ocean crust with ocean crust

Question 26

83. What determines the salinity of surface ocean water? a. Rate of precipitation. b. Rate of evaporation. c. The difference between evaporation and precipitation. d. The amount of dust blowing off of continents. e. The amount of continental rock weathering and stream transport to the ocean.

Answer 26

c. The difference between evaporation and precipitation.

Question 27

84. What happens to the concentration of phosphate in the deep ocean as the deep water from the North Atlantic slowly moves down and around the Southern Ocean and up into the North Pacific? a. Phosphate concentration decreases as the deep water moves from the North Atlantic to the North Pacific b. Phosphate concentration increases as the deep water moves from the North Atlantic to the North Pacific c. Phosphate concentration does not change much as the deep water moves from the North Atlantic to the North Pacific

Answer 27

b. Phosphate concentration increases as the deep water moves from the North Atlantic to the North Pacific

Question 28

86. With business as usual emissions (i.e., without cutting future emissions), what sort of timelines are we facing before polar seas become corrosive to calcium carbonate shells of planktonic organisms, and coral reef growth is slowed or stopped altogether? a. In 2 to 3 years b. In 20 to 30 years c. By the end of the century (2100) d. Acidity will never reach a level of measureable impact on any marine life

Answer 28

b. In 20 to 30 years

Question 29

87. What happens to the Trade Winds when the Pacific undergoes a transition from normal to El Niño conditions? a. Trade Winds speed up greatly b. Trade Winds slow down and even reverse direction c. Trade Winds remain about the same speed and direction

Answer 29

b. Trade Winds slow down and even reverse direction

Question 30

88. What is the magnitude of the energy imbalance in the earth system that has been created due to anthropogenic greenhouse gas emissions? a. 1 watts m-2 b. 2 watts m-2 c. 4 watts per m-2 d. 8 watts per m-2 e. 10 watts per m-2

Answer 30

b. 2 watts m-2

Question 31

92. How frequently do air guns explode during seismic surveys for oil exploration along the continental shelf? a. Every 10 seconds for a period of weeks to months b. Every 10 minutes for a period of weeks to months c. Every 30 minutes for a period of weeks to months d. Once per hour for a period of weeks to months

Answer 31

a. Every 10 seconds for a period of weeks to months

Question 32

93. Which overarching cause of the overfishing problem has grown worse over the past several decades? a. A big increase in family-run fishing effort b. A switch to industrial fishing methods using large ships that are owned by large financial holding companies c. A switch in fishing gear that is better able to catch fish more efficiently d. None of the aboves

Answer 32

b. A switch to industrial fishing methods using large ships that are owned by large financial holding companies

Question 33

94. Which kind of seafood is expected to have the highest concentration of toxic heavy metals? a. Shrimp b. Sardine c. Tilapia d. Tuna

Answer 33

d. Tuna

Question 34

8. Where did the oxygen in the atmosphere come from? a. Out-gassing of volcanoes b. Comets c. Asteroids d. Photosynthesis e. Respiration of anaerobic microbes

Answer 34

d. Photosynthesis

Question 35

9. Life on earth began in the ocean billions of years ago. When did life on land begin? a. About the same time as in the ocean b. About 2.5 billion years ago c. About 1.5 billion years ago d. About 550 million years ago e. About 65 million years ago

Answer 35

d. About 550 million years ago

Question 36

31. How fast does a tsunami wave propagate? a. About 5 miles per hour b. About 50 miles per hour c. About 500 miles per hour d. About 1,500 miles per hour

Answer 36

c. About 500 miles per hour

Question 37

32. Why is it so difficult to predict the height of a tsunami wave for a specific location? a. Wave dispersion causes the tsunami wave to change speed, direction, and height in complex and unpredictable ways. b. The constructive and destructive addition of wave crests and wave troughs, associated with the multiple individual tsunami waves created during a single event, are hard to predict. c. Bottom depth affects the wave height and the very detailed maps of the sea floor that are needed to predict wave height are not available. We know more about the surface of moon than the bottom of the ocean.

Answer 37

b. The constructive and destructive addition of wave crests and wave troughs, associated with the multiple individual tsunami waves created during a single event, are hard to predict.

Question 38

34. According to the figure below, semi-diurnal tides are expected: a. At high-latitude b. At mid-latitude c. Along the equator

Answer 38

c. Along the equator

Question 39

37. Why do we get rotary tides? a. The action of the trade winds and the westerly winds continuously turn the tide crest from the expected east to west direction to form a rotary motion. b. The combination of the blocking by continents and the action of the trade winds and westerly winds continually drive an Ekman Transport to the right of the wind direction. c. The combination of Coriolis force and blocking by continents. d. Wave refraction, resulting from deep water in the middle of an ocean basin and shallow water near the coast, causes the tide wave to turn in a clockwise direction in the northern hemisphere and a counter clockwise direction in the southern hemisphere.

Answer 39

c. The combination of Coriolis force and blocking by continents.

Question 40

39. Why is the atmosphere heated from below by a modestly warm earth surface and not from above by a very hot sun? a. Because the atmosphere does not absorb short wavelength radiation, but does absorb long wavelength radiation. b. Because the atmosphere does absorb short wavelength radiation, but does not absorb long wavelength radiation.

Answer 40

a. Because the atmosphere does not absorb short wavelength radiation, but does absorb long wavelength radiation.

Question 41

Why do the surface Trade Winds blow in the westward direction when the pressure gradient force that drives the winds is actually directed toward the equator from 30°N and 30°S? a. The winds are turned westward by the curvature of the earth. b. The winds are turned westward by the Coriolis force. c. The winds from the northern hemisphere and the southern hemisphere move to the equator by the pressure gradient force and then winds converge at the equator and have nowhere to go except to the east or west. They always move westward because the Cascade and Andes mountains block the possibility of any eastward movement.

Answer 41

b. The winds are turned westward by the Coriolis force.

Question 42

42. What happens to the surface ocean mixing depth in temperate (mid-latitude) regions as the surface ocean layer is cooled during fall, and into winter, periods? a. Mixing depth becomes shallower. b. Mixing depth becomes deeper. c. Mixing depth is unaffected by the cooling of the surface ocean.

Answer 42

b. Mixing depth becomes deeper.

Question 43

If winds are blowing from the south to the north along the west coast of the United States (e.g., the Washington, Oregon and California Coasts), would you expect to see Coastal Upwelling? a. Yes b. No

Answer 43

b. No

Question 44

46. How are the subtropical gyres forced to rotate in a clockwise direction in the northern hemisphere and counter-clockwise in the southern hemisphere? a. The trade winds and the westerly winds apply a lateral torque on the gyres and spin them up directly – sort of like unscrewing the lid from a jar. b. Strong upwelling, caused by Ekman layer divergence, brings deep water to the ocean surface in the center of the gyre and this excess water is turned by Coriolis force (to the right in the northern hemisphere) as the water flows outward from the upwelling center. c. The trade winds and the westerly winds pile water up in the center of the gyre and this creates a downward pressure force that leads to the turning of the gyres. d. The combination of Coriolis force and blocking of the continents forces east and west directed ocean currents to turn clockwise and counter clockwise.

Answer 44

c. The trade winds and the westerly winds pile water up in the center of the gyre and this creates a downward pressure force that leads to the turning of the gyres.

Question 45

48. How long does it take for deep ocean water to move from the North Atlantic to the North Pacific? a. About 10 years b. About 100 years c. About 200 years d. About 2,000 years e. About 10,000 years

Answer 45

d. About 2,000 years