Ocean Sciences 101 The Marine Environment OCEA 101 THE MARINE ENVIRONMENT MID-TERM EXAM

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1 OCEA 101 THE MARINE ENVIRONMENT MID-TERM EXAM Part I. Multiple Choice Questions. Choose the one best answer from the list, and write the letter legibly in the blank to the left of the question. 2 points each. 1. Keeping accurate time at sea is necessary to make A. measurements of latitude. B. measurements of longitude. C. measurements of latitude and measurements of longitude. D. accurate maps. E. measurements of longitude and accurate maps. 2. Oceanography as a modern science is usually dated from A. the Challenger Expedition. B. Nanson's polar voyage. C. Ammundsen's voyage to the Antarctic. D. Darwin s voyage on the Beagle. E. Nanson's polar voyage and Ammundsen's voyage to the Antarctic. 3. If a clock is set to Greenwich Mean Time and the sun is observed to reach its zenith at 10:00 A.M., what is the longitude? A. 45 E B. 45 W C. 30 E D. 30 W E The residence time for water in any of Earth's principal reservoirs can be calculated by dividing A. reservoir volume by rate of water supply. B. rate of water removal by reservoir volume. C. rate of water removal by water supply. D. None of these are correct. 5. The average depth of the ocean is about A m. B km. C mi. D. 11,000 m. E. 11,000 mi.

2 6. The Moho is located between the A. lithosphere and the asthenosphere. B. crust and the mantle. C. mantle and the outer core. D. inner and outer cores. E. continental margin and the abyssal plain. 7. Higher seafloor heat flow values are found A. along coastlines. B. in the middle of ocean basins. C. near ocean ridge systems. D. associated with abyssal hills. E. along the edges of trenches. 8. A fixed volcanic hot spot on Earth tends to produce a on a moving plate. A. series of volcanic peaks B. high landmass with a fixed location C. transform fault system D. submarine canyon and associated abyssal hills E. trench 9. The ocean s oldest sediments are found A. adjacent to a rift valley. B. on top of the basalt layer, far from spreading centers. C. adjacent to a transform fault. D. at the surface of sediment layers, far from spreading centers. E. in hot spots. 10. Inactive volcanic seamounts on top of the oceanic crust will A. continue to elevate with time. B. subside with time. C. remain in equilibrium once formed. D. keep a constant elevation. E. steepen in slope. 11. The sediments of the central deep-ocean basins of the North Pacific are formed chiefly from A. radiolaria. B. foraminaferia. C. red clay particles. D. diatoms. E. coral reefs. 12. Which type of sediment is the greatest contributor, on a world scale, to the sediments of the neritic zone? A. biogenous B. terrigenous C. hydrogenous D. cosmogenous E. volcanic

3 13. Why do small particles descend to the seafloor at rates exceeding expectation? A. the particles attract each other B. the particles increase their density C. the particles are incorporated into the fecal pellets of small animals D. the particles attract each other and the particles are incorporated into the fecal pellets of small animals E. the particles attract each other, the particles increase their density, and the particles are incorporated into the fecal pellets of small animals 14. Submarine canyons are associated with A. river systems. B. turbidity currents. C. volcanic eruptions. D. river systems and turbidity currents. E. turbidity currents and volcanic eruptions. 15. Density of seawater increases as A. temperature, salinity, and pressure decrease. B. temperature, salinity, and pressure increase. C. temperature increases and salinity and pressure decrease. D. salinity and pressure increase and temperature decreases. E. pressure increases and temperature and salinity decrease. 16. The maximum penetration of visible light in clear seawater is about meters. A. 100 B. 200 C. 300 D. 500 E A rapid change in salinity with depth is called a A. halocline. B. thermocline. C. photic level. D. midwater current. E. pycnocline. 18. The Coriolis effect arises primarily from the A. curvature of Earth's surface. B. rotation of Earth around its axis. C. rotation of Earth around the sun. D. effect of winds high in the atmosphere. E. motion of the oceans in their basins.

4 19. A parcel of air from the South Pole moves due north along the prime meridian. Over what longitude will it be found four hours later? A. 60 W B. 60 E C. 0 D. 40 E E. 40 W 20. Thermohaline circulation is driven by changes in A. viscosity. B. surface tension. C. convection. D. pressure. E. density. 21. The Coriolis effect A. deflects to the right in the Northern Hemisphere. B. deflects to the left in the Southern Hemisphere. C. has no effect at the equator. D. deflects to the right in the Northern Hemisphere and deflects to the left in the Southern Hemisphere. E. deflects to the right in the Northern Hemisphere, deflects to the left in the Southern Hemisphere, and has no effect at the equator. 22. Layering in the ocean occurs because A. surface processes form water layers of differing combinations of salinity and temperature. B. processes at depth add and subtract salt and heat. C. atmospheric processes control conditions at the surface. D. All of these are correct. E. surface processes form water layers of differing combinations of salinity and temperature and atmospheric processes control conditions at the surface. 23. The large oceanic surface current gyres centered on about 30 N A. rotate counterclockwise. B. do not rotate. C. have depressed surface elevations. D. rotate clockwise. E. alternate their direction of rotation with the seasons. 24. Currents are more intense on the side of the North Pacific and North Atlantic Oceans. A. northern B. southern C. eastern D. western E. None of these are correct; they are not more intense on one side.

5 25. Deep-ocean water in the Atlantic Ocean flows mainly A. east-west. B. north-south. C. to the right. D. to the left. E. None of these are correct; there is no deep-water flow. 26. If very warm and salty sea water is added on top of average seawater, A. the warm salty water will float at the surface. B. the warm salty water will sink to the bottom and stagnate. C. the warm salty water will sink and move rapidly out of the area. D. an overturn will begin. E. The answer cannot be determined unless the densities of the warm salty water and average sea water are known. 27. A zone of surface divergence is an area of and biological productivity. A. upwelling; high B. upwelling; low C. downwelling; high D. downwelling; low E. no vertical motion; average Part II. Fill in the blank/best word choice. Fill in the blank with what you think is the best answer to complete the sentence. 3 points each. 28. The ph of seawater is regulated by. 29. A nutrient-type element, such as exhibits the values for a vertical profile at the surface of the ocean. 30. A local shore wind controlled only by daily temperature variation between land and water will blow during the night.

6 Part III. Short Answer. Provide the best answer to each question in a few words (not an essay), or using a diagram. 5 points each. 31. Give an example of a major boundary current and a major wind-driven current. What (in simple terms) drives these currents? What is different about them? 32. Draw a cross-section of the Atlantic basin from North to South pole (across the Equator), and draw/label the major water masses (there should be at least 4).

7 33. What is the fate of ocean crust produced by sea floor spreading? Use a figure to assist on your answer. Present a specific example of where it is taking place. 34. Describe how two whales could theoretically communicate with each other over a distance of a few thousand kilometers. Where and why does such a feature exist?