Intro to oceans - Hilary online test compilation B

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1. The remains of which of the following type of planktonic organism are most likely to be remineralised (added back to seawater) and least likely to reach and accumulate on the ocean floor after death/being consumed

  • Radiolarians
  • Organic walled phytoplankton
  • Coccolithophores
  • Diatoms
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Other questions in this quiz

2. Why do dissolved oxygen concentrations decrease as deep water formed in the Atlantic ages during its transport to the Pacific Ocean?

  • Because the deep water warms significantly beteween the Atlantic and Pacific Ocean.
  • Bacteria organisms use oxygen during respiration/decomposition of organic matter
  • Oxygen is adsorbed by inorganic particles
  • Because the oxygen diffuses up to the surface and out into the atmosphere faster than it is transported in the bottom water currents moving towards the Pacific Ocean.

3. Which of the following statements is FALSE?

  • A constituent with an oceanic residence time of 100 years will be uniformly mixed throughout the oceans.
  • That the chemical composition of the oceans is in steady state means that the rate of addition of dissolved constituents to seawater is balanced by their rate of removal, so that their concentrations do not change significantly with time.
  • The major ions in seawater have a residence time longer than average ocean mixing time.
  • The residence time of an element in seawater can be estimated by dividing its mass in the ocean by its annual input from rivers

4. The constancy of composition means that although salinity may vary in the oceans the ratio of the major ions remain constant. Given that the ratio of sodium to chloride in the ocean is 0.554, which of the following statements is FALSE?

  • There is roughly half as much sodium in seawater than chloride, no matter where you collect your seawater sample.
  • There is roughly twice as much sodium in seawater than chloride, no matter where you collect your seawater sample.
  • There is roughly twice as much chloride in seawater than sodium, no matter where you collect your seawater sample.
  • Whether the salinity of the water is 30 or 40 the ratio of sodium to chloride will be 0.554

5. Which of the following statements about coccolithophores is FALSE?

  • Coccolithophores envelope themselves in coccoliths to form coccospheres.
  • Coccoliths are made up of minute plates of calcite usually less then 10 centimeters in size
  • When the algal cell dies, the coccosphere disintegrates easily, releasing the individual plates, the coccoliths, into suspension.
  • The white cliffs of Dover are formed of chalk that is mostly comprised of coccoliths

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