The constancy of composition of seawater is maintained because most of the major constituents exhibit conservative behaviour.
Most major ions behave non conservatively
Most minor and trace ions behave conservatively
The concentration of ions exhibiting conservative behaviour are significantly changed by biological and chemical reactions in seawater.
7. What is the definition of a bio-unlimited constituent
A constituent whose concentration in solution is unaffected by biological activity.
A constituent whose concentration in solution is affected by both physical and biological activity
A constituent whose concentration in solution is controlled primarily by biological activity.
. A constituent whose concentration in solution is controlled by scavenging.
8. What is the average oceanic mixing time?
500 years
50 years
5000 years
1,500 years
9. Which process can be described as "The cellular process by which molecules are oxidized, releasing energy and liberating carbon dioxide as a waste product".
Photosynthesis
Respiration
Dissolution
Recycling
10. If the oceans are in steady state the net input from rivers is balanced by material preserved in sediments. If the annual input of phosphate from rivers is 18.75 *109 mol yr-1, what amount of phosphate must be preserved in the sediments every year?
37.5 *109 mol yr-1,
18.75 *109 mol yr-1,
9.375 *109 mol yr-1
It is impossible to calculate with the information that has been given
11. Where would you expect to find the highest concentration of nitrate in bottom waters?
South Pacific
North Pacific
Mediterranean
North Atlantic
12. A secondary standard solution (4mM) is to be used to make up working standards of 6, 12 20 and 24 uM in 500 cm3 volumetrics. What volumes of the secondary standard solution (4mM) would you add to the volumetrics?
0.33, 016, 0.1 and 0.08 cm3
7.5, 15, 25 and 30 cm3
0.75, 1.5, 2.5 and 3 cm3
12.5, 20, 30 and 37.5 cm3
13. In what situation does the rate of production of marine aggregates generally exceed the rate of disaggregation and/or consumption, leading to the occurrence of aggregates at the sea bed?
During winter periods with low biological activity.
During period of high pressure
During seasonal blooms of phytoplankton
During periods of high winds delivering dust to the ocean
14. using the stoichiometric equation for respiration. In samples taken at different depths from below the euphotic zone, nitrate concentrations increase by 9.6M. Over the same depth, by how much would you predict the phosphate concentration to change ?
0.6 microM
128 microM
8 microM
5 microM
15. Which of the following statements is TRUE?
Variations in salinity affect the overall constancy of composition of seawater with respect to major constituents
Oxygen concentrations are lower in the north Pacific compared to the north Atlantic.
The deep oceans are poorly supplied with oxygen by deep water masses formed in polar regions
Elements classified as recycled have concentration profiles resembling those of scavenged elements.
16. Which of these statements is false?
The processes of photosynthesis and respiration are the two major controls on the depth distribution of phosphate and nitrate.
Photosynthesis uses the energy from sunlight to create organic compounds.
Photosynthesis occurs throughout the water column
Respiration occurs throughout the water column
17. For practical reasons a 4mM secondary standard is to be made from the primary (2.5M) standard solution. What volume of the 2.5 M standard solution would you need to add and dilute in a 1 litre volumetric to make the 4mM secondary standard.
10cm3
1.6 cm3
2.7cm3
1cm3
18. What happens to MOST of the biologically produced particulate matter that is produced in the upper, sunlit part of the ocean?
Most of the biological material reaches the sediments
Most biological material is recycled in the surface waters
Most biological material sinks through the water column and is decomposed and recycled in the deep water column below 1000m
Most biological material sinks through the water column and accumulates in the sediments below.
