6. If a sediment's contents is 55% opaline silica, what is the sediment commonly termed
Pteropod ooze
Pelagic Clay
Siliceous Ooze
Calcareous ooze
7. What is the main reason why water sinking in polar regions has a high oxygen concentration?
Mainly because the water is very cold and so the solubility of oxygen is enhanced
Mainly because phytoplankton abundance is very high in polar regions and so oxygen is supersaturated due to photosynthesis
Mainly because the waters in polar regions have a lower salinity than the rest of the ocean
Mainly because oxygen is more dense than any other gas, causing the water to sink
8. Which of the following statements is FALSE?
Most of the particulate matter falling to the ocean floor is from minerals supplied as wind borne dust.
Much of our information about the nature and distribution of sinking particulate organic matter in the water column comes from material collected in sediment traps.
Marine snow is an aggregate of detritus, living organisms and some inorganic matter.
The concensus between marine scientists is that the oceans are chemically in a steady state
9. Which of these statements is FALSE?
The oldest bottom waters are in the North Pacific and so we should expect them to be most impoverished in dissolved oxygen
Only half the elements found in the periodic table are found dissolved in seawater
Dissolved oxygen displays conservative behaviour in sea water
Profiles for scavenged elements show that their concentration decreases with depth.
10. 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
Organic walled phytoplankton
Diatoms
Coccolithophores
Radiolarians
11. Which of the following statements is FALSE?
The residence time of an element in seawater can be estimated by dividing its mass in the ocean by its annual input from rivers
A constituent with an oceanic residence time of 100 years will be uniformly mixed throughout the oceans.
The major ions in seawater have a residence time longer than average ocean mixing time.
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.
12. 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
