Ocean in Action End-of-Cycle Study Guide Ocean Circulation

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Ocean in Action End-of-Cycle Study Guide
Ocean Circulation

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1.Using the map of ocean surface currents above, what would be the most likely location for plastics and other solid waste pollution to collect?

2.What happens as warm water along the coast is blown away by wind and moved back out to sea, as cold, nutrient rich water is pushed up from along the land.


3.Which of the following are the 2 main drivers of global deep ocean currents?

1) Temperature

2) Salinity
4.What causes the wind and currents to curve/not travel in a straight line due to the rotation of the earth? In the north it curves to the right, and in the south it curves left.
The coriolis effect
5.What is the temperature and direction of the California Current, which flows along the west coast of North America?






6.How would a colder Scandanavia and Great Britain affect the thermohaline circulation of currents? (increase it, decrease it, cause it to shut down).

Shut it down
7.During an El Niño-Southern Oscillation (ENSO) event, which of the following best describes conditions in the eastern part of the tropical Pacific Ocean (e.g., near Peru and Ecuador)? What happens to the high and low pressure areas in the eastern and western Pacific?

The high ad low pressure areas are switched, so that the normal cold upwelling along the coast of the South America (Eastern Pacific) is replaced with higher sea surface temperatures and higher precipitation levels.

Fisheries and Aquaculture

8.Give four results of salmon farming (aquaculture).

    1. Environmental stress to salmon after their release

    2. Resource competition between farmed and wild salmon

    3. Increased susceptibility to diseases due to genetic uniformity

    4. Pollution of surrounding ocean with waste and excess feed

9.How is bottom trawling is detrimental to benthic organisms?

A boat drags a large net across the bottom of the ocean floor, destroying habitats, stirring up sedimentation, reducing spawning grounds, and catching unwanted bycatch.

10.Why has the maximum sustainable yield for ocean fisheries has been exceeded? (what happens annually? Refer to your Tragedy of the commons activity)

Too many marine fish of reproductive age are harvested annually

11.What is an economic approach to reduce overfishing/what could government eliminate for fisherman?

Eliminating subsidies

12.Which of the following laws was implemented in the US to govern the conservation and management of ocean fisheries?

Magnuson Fishery Conservation and Management Act
13.One of the world’s largest exporters of shrimp is Thailand, where coastal mangrove swamps are often destroyed to make room for shrimp farms. What are 4 ecological impacts of the destruction of mangrove forests for this type of aquaculture?

    1. Exposes the surrounding shorelines to coastal erosion

    2. Opens coastal areas to severe damage from storms and hurricanes

    3. Reduces biodiversity in important spawning and nursery areas

    4. May increase spread of diseases to wild populations of shrimp

Aquatic Biomes
14.Which part of the ocean would a marine biologist studying areas of high biodiversity be most likely to conduct research in?
Coral reefs in the neritic zone, above the continental shelf

15.Why are sharks are at the top of the food chain and their removal would have far-reaching consequences for the entire ecosystem. What is the term to describe an organism that would cause such a drastic change to the ecosystem, if it were removed?

Keystone species

16.Which of the following terms best describes an area where salt and freshwater mix that has a very high level of productivity? (3% salt water or brackish water exists here)

An estuary

17.Put the following aquatic biomes into the following catagories of salinity: River, Lake, Esturary, Coral Reefs (Coastal Marine Ecosystem), Deep ocean Marine Ecosystem.

Oligotrophic (0.5-5 psu)

Mesotrophic (5-18psu)

Polytrophic (18-30 psu)



Coral Reefs


Deep Ocean Marine Ecosystem

18.Wetlands surrounding a river, provide what ecosystem services?

1) Prevention of Flooding
2) remediation of toxic chemicals and excess nutrients

19.What does phytoplankton (the most abundant primary producer in the world) produce through photosynthesis in the ocean?

1) dissolved oxygen
2) glucose

20.The ecosystems with the world’s highest net primary productivity (NPP) per unit area are located in which part of the ocean?

Euphotic zone
Water Pollution

21.In a river ecosystem, dissolved oxygen concentrations drop quickly downstream from a point-source input of organic matter into the river. What is this effect most likely due to?

Increasing bacterial activity due to decay of organic matter

[Source: http://mdk12.org/instruction/clg/public_release/biology/G3_E5_I2.html]
22.Which organism in the food web above would be most likely to accumulate the highest concentration of a fat-soluble pollutant?

The Killer whale because of biomagnification, in which toxic pollutants are not broken down, and travel up the food chain, accumulating at the top.

23.In what way does the Great Pacific Garbage Patch represent a “tragedy of the commons”?

Pacific Rim countries are polluting the water in a way that affects the quality of the ocean for all, but no one is accountable for it.
24.Which of the following is the most common cause of cultural eutrophication in surface waters?

Runoff of nitrate into bodies of water

25.How does logging/ deforestation lead to non-point source pollution?

Logging and deforestation leads to sedimentation, which lowers water quality. It is not easily identifiable, and therefore is considered a non-point source of pollution.

26.When we did our toxicity lab, we found that worm (we used black worms) tend to be very tolerant of pollution, and resistant to high toxicity levels. Explain why the presence of black worms or sludge worms and anaerobic bacteria are indicators of polluted water.

Sludge worms and anaerobic bacteria

27.What is the number 1 source of oil pollution in the ocean? (surprisingly)
Storm water runoff from land

28.What are three of the most common methods employed to clean up oil spills?

Large floating booms, skimmer boats, and chemical dispersants

29.Name 3 point sources of pollution.

  1. Factory effluent (emissions and discharge)

  2. A specific active or inactive mine

  3. Sewage Treatment plant

30.A marine scientist suspects that runoff from nearby farms is creating a hypoxic zone (area of low oxygen content) in a coastal area. Which of the following water quality tests would be best suited to determining whether the area is actually hypoxic?

Dissolved oxygen

31.Environmental conditions in coastal estuaries vary hourly and seasonally. What are TWO important causes for the variation in the temperature and/or salinity of an estuary. Be sure to include the connection between each cause and temperature and/or salinity.



32.What are 2 reasons that wetlands are ecologically important?



33.What are 2 reasons that wetlands are economically important?



34.Explain THREE ways in which humans have had a negative impact on or have degraded coastal wetlands.

35.What are 2 pieces of legislation that could reduce the negative impacts that humans have on the wetlands, and explain using the provisions of each act how they might prevent/reduce wetland degradation.



36.Excess carbon dioxide (CO2 ) dissolved in the ocean (due to increased pollution) could affect pH. pH is the amount of H+ that can be donated. Write the chemical equation, that explains why excess CO2 may increase the acidity of the ocean?

37.Coral reefs are produced when corals acquire calcium ions (Ca2+) and carbonate ions (CO32-) from seawater and deposit solid CaCO3 to form their exoskeletons. How might coral reefs be affected by excess CO2?

38. Look at the chart above. Explain 2 reasons why the movement of carbon into the ocean has been increasing since 1850, as a result of CO2 production by humans.

In order to model the effects of ocean acidification on coral reefs, some simplifying assumptions can be made. Use the assumptions in the table below to perform the calculations that follow.
Assume that the total global area of corals growing in reefs is 2.5 x 1011m2

Assume that corals grow only vertically and that the average vertical growth rate of corals is 3 mm/year.

Assume that the average density of CaCO3 in corals is 2 x 103 kg/m3.

  1. Calculate the current annual global increase in volume, in m3 per year, of CaCO3 in coral reefs. Show all steps in your calculation.

Step 1: What is the total global area (m2) of coral reefs?

Step 2: convert mm to m, to determine the vertical m/year.

Step 3: What is the volume (m3) per year CaCO3? (Volume= area times vertical height)

  1. Calculate the current annual global increase in mass, in kg, of CaCO3 in coral reefs. Show all steps in your calculation.

Step 1: What is the annual global volume increase that you calculated in part (i)?

Step 2: What is the density of CaCO3 in kg/m3?

Step 3: Using the formula for density (D=m/v) what is the increase in global mass in kg of CaCO3 in coral reefs?

  1. Because of ocean acidification, it is expected that in 2050 the mass of CaCO3 deposited annually in coral reefs will be 20 percent less than is deposited currently. Calculate how much less CaCO3, in kg, is expected to be deposited in 2050 than would be deposited if ocean water pH were to remain at its current value.

Step 1: What is the annual global increase in mass in kg of CaCO3 in coral reefs? (from part ii)

Step 2: find 20% of that mass using multiplication.

39. Give 4 reasons why destroying coral reefs would be harmful to the environment, and why?



40. What are 3 environmental problems (other than one due to ocean acidification or loss of coral reefs) that humans cause and affect marine ecosystems on a global scale?


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