Cambridge A Level Marine Science 9693 — 2018 May/June Paper 4 · Variant 0

1 Scientists carried out an investigation into the composition of water samples taken from an area of the Arctic Ocean. They measured the concentration of dissolved oxygen, and also the quantity of chlorophyll present in a 1 dm3 sample. Sampling was carried out on the first day of each month from late winter, through spring and into early summer. The condition of the surface ice on the water was also determined. It was assessed as increasing in size or melting. The results are shown in Table 1.1. Table 1.1 quantity of oxygen time condition chlorophyll concentration (month) of ice sheet / arbitrary units / mg dm–3 December 1000 8.5 increasing January 500 8.5 increasing February 500 7.8 increasing March 500 6.9 increasing April 2000 7.6 melting May 6000 8.4 melting June 3000 8.6 melting July 1500 8.8 melting (a) Plot a graph to show the changes in quantity of chlorophyll and oxygen concentration over time. [5] (b) (i) Explain the relationship between the quantity of chlorophyll and the oxygen concentration shown in Table 1.1 and your graph. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [2] (ii) Use the information in Table 1.1 to suggest two explanations, other than the changes in the quantity of chlorophyll, for the changes in oxygen concentration. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [2] (c) It has been suggested that global warming could affect ocean productivity. Use the information in Table 1.1 and your graph to suggest how ocean productivity could be affected. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [2] [Total: 11]

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2 A student carried out an investigation into the effect of size on the time taken for dye to diffuse to the centre of cubes of agar jelly. Cubes of agar jelly of different side length were placed into a solution of dye, as shown in Fig. 2.1. beaker solution of dye cube of agar jelly Fig. 2.1 The times taken for the dye to reach the centre of the cubes of agar jelly were recorded. The results are shown in Table 2.1. Table 2.1 surface area : time taken for side length of surface area of volume of volume ratio dye to reach cube / mm cube / mm2 cube / mm3 of cube centre / s 5 150 125 1.2 : 1 35 10 600 1000 0.6 : 1 76 15 1350 174 20 2400 8000 0.3 : 1 296 (a) (i) Calculate the surface area : volume ratio for the cube with a side length of 15 mm. Show your working. ................................................................ [2] (ii) Use the information in Table 2.1 to explain why larger marine organisms require specialised gas exchange organs. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [3] (b) Temperature also affects the time taken for dye to diffuse to the centre of a cube of agar jelly. Describe an experiment that you could do to investigate the effect of temperature on the rate of diffusion of the dye. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [4] [Total: 9]

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3 (a) (i) Explain why the precautionary principle is used when considering whether to permit the aquaculture of genetically engineered fish such as salmon. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [2] (ii) Outline how and why salmon have been genetically engineered for aquaculture. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [5] (b) Both genetically engineered and non-genetically engineered salmon are grown using aquaculture systems. Explain the negative impacts that aquaculture could have on wild fish near to a salmon farm. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [8] [Total: 15]

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4 (a) Mass tourism in coastal areas can have negative effects on marine environments. These can be caused by large scale agriculture to meet the demands for food and the use of desalination plants to meet the demands for fresh water. (i) Explain the negative ecological impacts of agriculture on the marine environment. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [4] (ii) Explain the negative ecological impacts of desalination plants on the marine environment. ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ........................................................................................................................................... ...................................................................................................................................... [4] (b) Damage to the marine environment can be reduced by responsible tourism practices. A new coastal ecotourist resort is planned. Describe the responsible practices that should be included in the development of this resort. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... .............................................................................................................................................. [7] [Total: 15]

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