Cambridge A Level Marine Science 9693 — 2021 Oct/Nov Paper 1 · Variant 0

This document has 20 pages. Any blank pages are indicated. Cambridge International AS & A Level DC (CE/CT) 207520/7 © UCLES 2021 [Turn over * 2 0 9 6 3 4 3 5 2 7 * MARINE SCIENCE 9693/01 Paper 1 AS Structured Questions October/November 2021 1 hour 30 minutes You must answer on the question paper. No additional materials are needed. INSTRUCTIONS ● Answer all questions. ● Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs. ● Write your name, centre number and candidate number in the boxes at the top of the page. ● Write your answer to each question in the space provided. ● Do not use an erasable pen or correction fluid. ● Do not write on any bar codes. ● You may use a calculator. ● You should show all your working and use appropriate units. INFORMATION ● The total mark for this paper is 75. ● The number of marks for each question or part question is shown in brackets [ ].

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3 9693/01/O/N/21 © UCLES 2021 [Turn over Answer all the questions in the spaces provided. 1 (a) Fig. 1.1 shows a food web in a marine ecosystem. leopard seal arctic cod krill baleen whale zooplankton phytoplankton Fig. 1.1 (i) Use Fig. 1.1 to write the food chain that includes a baleen whale. … [1] (ii) State the number of trophic levels in the food web in Fig. 1.1. … [1]

4 9693/01/O/N/21 © UCLES 2021 (b) Fig. 1.2 is a photograph of a krill. Fig. 1.2 (i) Suggest how a lack of dissolved calcium in sea water may affect krill. … … [1] (ii) Explain how a lack of nitrogen may affect krill. … … … … [2]

5 9693/01/O/N/21 © UCLES 2021 [Turn over (c) Fig. 1.3 is a pyramid of energy for a marine food chain. large fish small fish zooplankton phytoplankton 3 2 4 1 trophic level 1260 7980 126 31 080 energy / kJ m–2 yr–1 Fig. 1.3 (i) Calculate the efficiency of transfer of energy between the phytoplankton and the zooplankton. Show your working. …% [2] (ii) Describe how the shape of a pyramid of biomass for trophic levels 1 and 2 may differ from the one shown in Fig. 1.3. Explain reasons for this difference. … … … … … … [3] [Total: 10]

6 9693/01/O/N/21 © UCLES 2021 2 Scientists recorded the stomach contents of two different types of fish, Pterois volitans (red lionfish) and Lutjanus apodus (schoolmaster snapper). Fig. 2.1 shows photographs of the two fish. P. volitans L. apodus Fig. 2.1 Table 2.1 shows a summary of the results. Table 2.1 P. volitans L. apodus number of different species found in stomach 21 8 percentage of species that were crustaceans 9 85 percentage of species that were fish 91 15 (a) (i) The species that was most abundant in the stomach contents of P. volitans was the damselfish Stegastes leucostictus. Describe the relationship between P. volitans and S. leucostictus. … … … … [2]

7 9693/01/O/N/21 © UCLES 2021 [Turn over (ii) Use the information in Table 2.1 to compare the niches of P. volitans and L. apodus. … … … … … … [3] (b) S. leucostictus often has parasites inside its intestine. Suggest and explain the effect of this on the efficiency of energy transfer from S. leucostictus to P. volitans. … … … … [2] [Total: 7]

8 9693/01/O/N/21 © UCLES 2021 3 Fig. 3.1 is a photograph of a hydrothermal vent. Fig. 3.1 (a) (i) State two environmental conditions found at a hydrothermal vent. 1 … 2 … [2] (ii) Explain why there is low biodiversity at a hydrothermal vent. … … … … [2] (b) With reference to named organisms, describe succession at a hydrothermal vent. … … … … … … [3]

9 9693/01/O/N/21 © UCLES 2021 [Turn over (c) (i) State the initial source of energy for the food chain in a hydrothermal vent. … [1] (ii) Explain the meaning of the term productivity. … … … … [2] (iii) Suggest how an increase in underwater volcanic activity can increase productivity at a hydrothermal vent. … … … … … … [3] [Total: 13]

10 9693/01/O/N/21 © UCLES 2021 4 Fig. 4.1 is a photograph of a sandy shore. Fig. 4.1 (a) Describe how the type of shore shown in Fig. 4.1 is formed. … … … … … … … … [4] (b) Explain why few producers are able to survive in the type of shore shown in Fig. 4.1. … … … … [2]

11 9693/01/O/N/21 © UCLES 2021 [Turn over (c) Describe and explain two adaptations that help organisms to survive on a sandy shore. adaptation 1 … … … … adaptation 2 … … … … [4] [Total: 10]

12 9693/01/O/N/21 © UCLES 2021 5 Table 5.1 shows the chemical composition of two samples of sea water from different locations. Table 5.1 substance concentration in sea water / g per 100 g of water location A location B Na+ 1.09 4.00 Mg2+ 0.13 4.30 Ca2+ 0.04 1.70 K+ 0.04 0.76 Cl – 1.90 21.80 Br – 0.01 0.50 (a) The percentage of dissolved substances (salinity) in sea water at location A is 3.21%. Calculate the percentage of dissolved substances in sea water at location B. … % [1] (b) Environmental conditions affect the salinity of sea water. Suggest reasons for the differences in salinity between location A and location B. … … … … … … [3]

13 9693/01/O/N/21 © UCLES 2021 [Turn over (c) Table 5.2 shows the pH of sea water at both locations. Table 5.2 location A location B pH 8.1 5.9 Suggest reasons for the difference in pH between the two locations. … … … … … … [3] [Total: 7]

14 9693/01/O/N/21 © UCLES 2021 6 (a) Fig. 6.1 shows a mid-ocean ridge. magma plate 1 plate 2 Fig. 6.1 (i) Draw two arrows on the plates on Fig. 6.1 to show the direction of movement of the two plates. [1] (ii) Draw a line labelled X on Fig. 6.1 to show the location of the youngest rock. [1] (iii) State the name of the type of plate boundary shown in Fig. 6.1. … [1] (iv) Explain the reason for the movement of the plates shown in Fig. 6.1. … … … … … … [3] (v) The rocks either side of the type of plate boundary shown in Fig. 6.1 can provide evidence for the plate tectonic theory. Describe this evidence. … … … … [2]

15 9693/01/O/N/21 © UCLES 2021 [Turn over (b) Underwater earthquakes often occur at convergent boundaries. (i) Explain how tectonic activity leads to earthquakes. … … … … … … … … [4] (ii) State the name of one feature found at convergent boundaries. … [1] [Total: 13]

16 9693/01/O/N/21 © UCLES 2021 7 A core sample was taken from a coral reef by drilling down through the reef to a depth of several metres. The reef was located in a region that experiences one cool season and one warmer season each year. Fig. 7.1 is a diagram showing the core sample. growth during warmer months growth during cooler months lines representing stress periods experienced by the coral Fig. 7.1 (a) Use Fig. 7.1 to work out how many years of coral growth are represented in this core sample. … [1] (b) Identify the band that shows the fastest rate of growth on Fig. 7.1. Label this with an X. [1] (c) Suggest reasons for the periods of faster growth shown in Fig. 7.1. … … … … … … [3]

17 9693/01/O/N/21 © UCLES 2021 [Turn over (d) Suggest reasons for the stress periods represented by the lines in Fig. 7.1. … … … … [2] (e) Drilling cores is one way of reconstructing the history of a coral reef. State one other method that can be used. … [1] [Total: 8]

18 9693/01/O/N/21 © UCLES 2021 8 Fig. 8.1 shows the major surface currents in the oceans. Fig. 8.1 (a) Describe and explain the different direction of currents in the northern and southern hemisphere. … … … … … … … … [4] (b) Mixing occurs between the water at the surface and deep ocean water. State two factors that cause this mixing. 1 … 2 … [2] (c) State the name of the process that brings water from the sea bed to the surface. … [1] [Total: 7]

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