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The Marine Environment Ocea 101, Winter 2007 |
 Mid Term Exam - Winter 1998(students have 1 hour and 15 minutes to complete the exam - students get to choose one question to not answer) 1. There is essentially no record of the first 0.6 to 0.7 billion years of Earth's history. Why is there no fossil record of this Archean Era? At approximately 3.9 Ba the "stage was set" for life to evolve on Earth. List 4 conditions or aspects of Earth at that time which were critical in "setting the stage". At roughly 2 Ba an entirely new and dramatically different "stage was set" on Earth to allow new forms of life to evolve. Describe this change and tell who was responsible and how and why the change occurred. What new forms of life subsequently evolved?
2. Using a detailed figure, describe the process of sea floor spreading. Present a specific example of where this is taking place on our modern Earth. What is the driving force for this tectonic activity? What is the ultimate source of energy for this process? Will the Earth continue to be tectonically active for the remainder of its life-time? Explain the reasons for each of your answers.
3. What is the fate of the ocean crust produced by sea floor spreading? Use a figure to assist in your answer. Present a specific example of where this is taking place. Describe 3 distinct geophysical phenomena which result from the destruction of this ocean crust. Explain why and how.
4. Describe submarine canyons (use a figure) and present the most widely supported theory concerning their origin.
5. The heat budget for the entire world ocean is expressed in your text book by these average values: QSun = Qradiation + Qevaporation + Qconduction 100% 41% 53% 6% QSun is the amount of heat added to the surface ocean from the Sun's radiation. Describe the 3 terms on the right side of the equation. What properties cause the Qevaporation term to be so important? In what latitudes of the oceans would each of these various terms be most important? Explain why.
6. Describe (with the help of a figure) the North Pacific subtropical gyre system. Name the various currents comprising this gyre system. Describe the difference between the western and eastern boundary surface currents. Describe and explain the forces that drive this gyre system.
7. Describe the deep water circulation in the Atlantic and Pacific oceans (use a figure). What are the deep water masses called? Where are they formed? What drives the deep water circulation? Why is no deep water formed in the North Pacific?
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OCEA 101 - The Marine Environment - Midterm Exam - Winter 1999
1. a. What is the fate of the ocean crust produced by sea floor spreading? Use a figure to assist in your answer. b. Present a specific example of where this process is taking place. c. Describe 3 distinct geophysical phenomena which result from the destruction of this ocean crust.
2. a. List five characteristics of liquid water that make it relatively unique. b. Explain why and how liquid water has each of these five special attributes. c. Discuss how each of the five properties is important in the physical and/or biological environment.
3. Examine the distribution of salinity in the surface waters of the world's oceans presented in the attached Figure 1. a. Describe the processes leading to this salinity distribution. We recommend the use of another figure to help explain the observed salinity distribution. b. Present a definition of the term salinity and how oceanographers measure salinity today.
4. a. Present two important chemical weathering reactions (stoichiometrically balanced) that occur when rain (from the hydrological cycle) falls on the continents. b. What is the most abundant cation and anion in average river water? c. What is the major cation and anion in seawater? d. Define the term "oceanic residence time" and use it to explain the discrepancy between the flux of ions being delivered to the ocean via rivers and the concentration of ions in the oceans. e. What are the approximate oceanic residence times of the two cations mentioned in parts b and c?
5. a. Describe how two whales could theoretically communicate with each other over a distance of a few thousand kilometers. b. Where and why does such a feature exist? c. If the whales were 4,500 kilometers apart, approximately how long would it take to receive a response?
6. a. Draw a figure of the surface water circulation pattern in the North Pacific subtropical gyre. b. Name the various boundary currents. c. On a separate figure draw the prevailing winds occurring over the latitudes of importance to this gyre system. d. Describe why the surface water currents are the way you drew them. e. Explain the difference between eastern and western boundary currents and why these differences exist. ___________________________________________________________________________________ Ocean Sciences 101 - MID TERM EXAM - Winter 2000
1. a. At what time in Earth's history were the oceans considered to be a "permanent" feature of planet Earth? What process would have led them to be "temporary"? b. When is there the first evidence of life on Earth? Describe this first life and the fossil evidence that remains. c. Describe when and how the Earth's surface changed from being anoxic to oxygenated. This "set the stage" for what sort of organisms or evolution to take place?
2. Draw a water molecule. Describe the three types of bonds or attractions involved between atoms and between molecules in liquid water. Which of these interactions is the reason for liquid water having such a high heat capacity and latent heat of vaporization. Describe why this is so. Finally, describe why water is such an effective solvent for dissolving salts such as sodium chloride (NaCl).
3. Draw a cross section of a hypothetical ocean basin (including the ocean, crust and upper mantle) with a spreading center in the middle and an active margin on the right side and a passive margin on the left side. Draw arrows for motion, label the key features and indicate the approximate thickness of the various features.
4. If you were a coral reef specialist interested in the evolution of the Great Barrier Reef off Australia over the past 30 million years, what geophysical processes would you have to take into account to explain the evolution of the Great Barrier Reef over this time interval. Describe in some detail.
5. Describe and label the surface currents in the major subtropical gyre in the North Pacific. Describe why this major gyre exists and also describe and explain the differences between the western and eastern boundary currents. _________________________________________________________________________________
FINAL EXAMOCEA 101 - THE MARINE ENVIRONMENT - WINTER 1998
1. (25) Draw vertical profiles of temperature, nitrate and dissolved molecular oxygen in the central North Pacific gyre. Discuss the key features of the profiles and explain the reasons for these features.
2. (25) Oceanic Primary Production by phytoplankton has been separated into two components: New Production and Regenerated Production. Describe these two types of production and explain how they are defined or what they are based upon (use a figure to assist in your answer). Explain what is meant by the term "f-ratio". How would the f-ratio vary between a coastal upwelling regime and an oligotrophic central gyre? Discuss what this means with respect to cycling of fixed-nitrogen within the surface waters.
3. (25) Present four different types of regions of high primary production in the ocean and provide a specific example of each. Explain why each of these regions has relatively high productivity. What are the processes leading to the high productivity? How it might the Primary Productivity vary during the year in these regions?
4. (25) Using the concepts of food chains, food webs, and trophic levels, describe the difference between the yield of a fisheries based upon tuna in the central North Pacific and anchovies in a coastal upwelling system. Make use of figures and describe the two systems in some detail.
5. (25) Calcareous oozes are the dominant sediment covering much of the North Atlantic sea floor, yet are relatively rare in the North Pacific. Describe the key factors that lead to calcareous sediments being the dominant sediment type. Then describe the reasons for the difference between the North Atlantic and the North Pacific.
6. (25) Present five different mortality modes or impact mechanisms by which harmful algal blooms can either directly or indirectly cause harm. Present an example of each.
7. (25) a.) Present a growth response curve for a phytoplankton species responding to both an essential (such as Cu2+ ) and a non-essential metal (Pb2+ ). b.) cyanobacteria are much more sensitive to Cu2+ toxicity than are diatoms. Using growth response curves for these two organisms, describe how the carefully controlled addition of Cu2+ to a coastal lagoon could be used to control a potential harmful bloom of cyanobacteria, yet not harm the rest of the ecosystem. ________________________________________________________________________________ OCEA 101 - Final Exam - Winter 1999
(25) 1. A) Draw vertical profiles (0-4000 meters) of temperature, nitrate (NO3-), and dissolved molecular oxygen (O2) in the central North Pacific gyre near Hawaii. B) discuss the key features of the profiles and explain the reasons or processes leading to these features.
(25) 2. A) Describe the process of coastal upwelling. Why and how does it occur? B) Name (and show on a map) 4 important coastal upwelling regimes in the world's oceans. C) Describe the influence of coastal upwelling on phytoplankton productivity. D) Describe an important food chain that occurs in coastal upwelling regimes.
(25) 3. In question #2 you have already described coastal upwelling regimes. A) Now in this question, describe 3 other types of high productivity regions in the oceans. B) Provide a specific example of each of the 3 types of high productivity regions. C) Explain why each of these 3 regions has high primary productivity. D) How does the productivity in these various regions vary seasonally? Explain why.
(25) 4. A) Describe the Gulf Stream. Where is it found? What kind of current is it? B) Describe the formation of both a cold core ring and a warm core ring. With respect to the Gulf Stream, where are these two types of rings or eddies found? What size are they? C) If on an oceanographic cruise, you came across a counter-clockwise rotating ring (or eddy), would you tell your colleagues it was a warm or cold core ring? Why? D) Would you expect this ring to be more or less productive than the surrounding waters? Why?
(25) 5. Shown below is a simplified drawing of the location of the East Pacific Rise, the Equator, and the location of a core obtained at 10 degrees North in the central North Pacific Ocean. Also drawn below is a description of the sediment type found in the sediment core. A) Put together the paleoceanographic history of the core and describe why the sediment type varies as it does. B) What is the source of each of the sediment types?
(25) 6. Halogenated hydrocarbons such as DDT and PCB's are examples of chemical pollutants which have caused deleterious effects in the marine environment. A) Describe these chemicals and provide a detailed example of how they have caused deleterious effects in the marine environment. B) What steps have been taken to alleviate these problems? __________________________________________________________________________________ |
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