Cambridge A Level Marine Science 9693 — 2021 May/June Paper 1 · Variant 1

This document has 16 pages. Any blank pages are indicated. DC (RW/SW) 201655/6 © UCLES 2021 [Turn over * 4 6 7 9 9 1 1 8 3 3 * MARINE SCIENCE 9693/11 Paper 1 AS Structured Questions May/June 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 [ ]. Cambridge International AS & A Level

2 9693/11/M/J/21 © UCLES 2021 Answer all the questions in the spaces provided. 1 Table 1.1 shows the predicted and actual heights of high and low tides at a port for one day. Table 1.1 predicted tide height / m actual tide height / m high tide 6.1 7.1 low tide 0.9 1.9 high tide 6.9 8.3 (a) (i) Suggest two reasons for the differences between the predicted and actual tide heights on this day. 1 … 2 … [2] (ii) Suggest two negative impacts this difference in tide height could have on the local human community. … … … … [2]

3 9693/11/M/J/21 © UCLES 2021 [Turn over (b) A spring tide is formed when the Moon and the Sun are in alignment with the Earth. Fig. 1.1 shows the spring tide bulge over a 24‑hour period as the Earth rotates on its axis. 00:00 Key moon midnight 06:00 6am 12:00 midday 18:00 6pm 00:00 midnight time: X X X X X Fig. 1.1 (i) Use the information in Fig. 1.1 to sketch a curve on the axes below, showing the tide height at X over a 24‑hour period. 00:00 tide height at X 06:00 12:00 18:00 00:00 [2] (ii) Describe one way the curve would look different when the Moon and the Sun are not aligned with the Earth. … … [1] [Total: 7]

4 9693/11/M/J/21 © UCLES 2021 2 Fig. 2.1 shows the quantity of energy that enters and leaves a single sea bream. The values are given in arbitrary units (a.u.). sea bream waste material sinks 3300 a.u. 2200 a.u. 720 a.u. W consumer Fig. 2.1 (a) (i) State two processes occurring at W. 1 … 2 … [2] (ii) Explain what happens to the energy in the waste material that sinks. … … … … [2] (iii) Calculate the efficiency of energy transfer between the sea bream and the consumer as a percentage. Space for working. …% [3]

5 9693/11/M/J/21 © UCLES 2021 [Turn over (b) Fig. 2.2 shows a pyramid of numbers for a food chain that includes sea bream. small crustacea sea bream tuna nematodes algae Fig. 2.2 (i) State the trophic level of tuna. … [1] (ii) Explain the reason for the shape of the pyramid of numbers shown in Fig. 2.2. … … … … [2] (iii) Describe how a pyramid of energy for the same food chain will differ from the pyramid of numbers shown in Fig. 2.2. … … [1]

6 9693/11/M/J/21 © UCLES 2021 (c) Sea bream require a variety of nutrients in their diet, including phosphorus and calcium. (i) State two uses of phosphorus in sea bream. 1 … 2 … [2] (ii) Suggest the pathway of phosphorus from the sea water into the sea bream. … … … … [2] (iii) Not all nutrients in one trophic level are passed onto the next trophic level. Suggest one reason why all the calcium in the sea bream is not used by the tuna. … … [1] [Total: 16]

7 9693/11/M/J/21 © UCLES 2021 [Turn over 3 Fig. 3.1 shows the relationship between temperature, salinity and oxygen concentrations in water. Each plotted line shows one oxygen concentration, which is stated in the circle on each line. Oxygen concentration is given in mg dm–3. 30 0 5 10 15 20 salinity / ‰ temperature / °C 25 30 35 40 45 25 20 15 10 5 0 14 13 12 11 10 9 8 7 6 Fig. 3.1 (a) Complete the sentence: At a given temperature, as salinity increases oxygen concentration … [1] (b) Predict the oxygen concentration in water at a temperature of 15 °C and a salinity of 35 ‰. … mg dm–3 [1] (c) Use the information in Fig. 3.1 to explain the effect of increasing depth on oxygen concentration in water. … … … … … … [3] [Total: 5]

8 9693/11/ M / J /21 © UCLES 2021 4 Fig. 4.1 shows the global historical occurrence of tropical cyclones (hurricanes or typhoons) for a period of 150 years. equator land bands of tropical cyclones Key Fig. 4.1 (a) (i) State why no tropical cyclones have been observed around the equator. … … [1] (ii) Suggest why no tropical cyclones have formed around South America. … … [1]

9 9693/11/M/J/21 © UCLES 2021 [Turn over (b) (i) Describe and explain the energy transfers that occur during the formation of a tropical cyclone. … … … … … … … … [4] (ii) State how coral reefs reduce the effect of tropical cyclones and storm surges on coastal communities. … … [1] (c) Suggest the impacts of a tropical cyclone on a sandy shore. … … … … [2] [Total: 9]

10 9693/11/M/J/21 © UCLES 2021 5 (a) (i) State the meaning of the term biodiversity. … … … … [2] (ii) Explain why sandy shores have a low biodiversity compared to rocky shores. … … … … … … [3] (iii) Describe how a predator‑prey relationship differs from a parasitic relationship. Use named examples in your answer. … … … … … … … … [4]

11 9693/11/M/J/21 © UCLES 2021 [Turn over (b) Name and describe the interrelationship between coral polyps and zooxanthellae. name … description … … … … … … [4] [Total: 13]

12 9693/11/ M / J /21 © UCLES 2021 6 Volcanic islands can form near to convergent (destructive) plate boundaries between two oceanic tectonic plates. Fig. 6.1 shows the formation of these islands. X volcanic islands Fig. 6.1 (a) Name the feature labelled X. … [1] (b) Outline the processes that create the volcanic islands shown in Fig. 6.1. … … … … … … … … [4] (c) Name the type of wave that could be produced when a large underwater earthquake suddenly displaces a large volume of water. … [1] [Total: 6]

13 9693/11/M/J/21 © UCLES 2021 [Turn over 7 Fig. 7.1 shows the location of the Great Barrier Reef on the east coast of Australia. N Great Barrier Reef Australia equator Fig. 7.1 (a) State three conditions that are suitable for tropical reef‑building coral growth on the Great Barrier Reef. 1 … 2 … 3 … [3] (b) In late summer of 2016 around 30% of the Great Barrier Reef coral polyps died. This was particularly noticeable on the northern end of the reef. Suggest three causes for the death of the corals. 1 … … 2 … … 3 … … [3]

14 9693/11/M/J/21 © UCLES 2021 (c) The rate of loss in 2016 was higher than historical coral loss events. Suggest how scientists determined the historical rate of loss. … … … … … … [3] [Total: 9]

15 9693/11/M/J/21 © UCLES 2021 8 Wet and dry monsoon winds occur in areas of the Asian continent at different times of the year. (a) Describe the factors that cause the formation of a dry monsoon wind. … … … … … … … … [4] (b) (i) During the wet monsoon there is high precipitation over the land. Discuss the impact this could have on the physical and chemical properties of sea water in this region. … … … … … … … … [4] (ii) Explain how a change in the chemical properties of sea water could increase the productivity of the oceans in this region. … … … … [2] [Total: 10]

16 9693/11/M/J/21 © UCLES 2021 BLANK PAGE The boundaries and names shown, the designations used and the presentation of material on any maps contained in this question paper/insert do not imply official endorsement or acceptance by Cambridge Assessment International Education concerning the legal status of any country, territory, or area or any of its authorities, or of the delimitation of its frontiers or boundaries. Permission to reproduce items where third‑party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. To avoid the issue of disclosure of answer‑related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series. Cambridge Assessment International Education is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.

This document consists of 12 printed pages. © UCLES 2021 [Turn over Cambridge International AS & A Level MARINE SCIENCE 9693/11 Paper 1 AS Structured Questions May/June 2021 MARK SCHEME Maximum Mark: 75 Published This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge International will not enter into discussions about these mark schemes. Cambridge International is publishing the mark schemes for the May/June 2021 series for most Cambridge IGCSE™, Cambridge International A and AS Level components and some Cambridge O Level components.

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 2 of 12 Generic Marking Principles These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the specific content of the mark scheme or generic level descriptors for a question. Each question paper and mark scheme will also comply with these marking principles. GENERIC MARKING PRINCIPLE 1: Marks must be awarded in line with: • the specific content of the mark scheme or the generic level descriptors for the question • the specific skills defined in the mark scheme or in the generic level descriptors for the question • the standard of response required by a candidate as exemplified by the standardisation scripts. GENERIC MARKING PRINCIPLE 2: Marks awarded are always whole marks (not half marks, or other fractions). GENERIC MARKING PRINCIPLE 3: Marks must be awarded positively: • marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the scope of the syllabus and mark scheme, referring to your Team Leader as appropriate • marks are awarded when candidates clearly demonstrate what they know and can do • marks are not deducted for errors • marks are not deducted for omissions • answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the question as indicated by the mark scheme. The meaning, however, should be unambiguous. GENERIC MARKING PRINCIPLE 4: Rules must be applied consistently, e.g. in situations where candidates have not followed instructions or in the application of generic level descriptors.

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 3 of 12 GENERIC MARKING PRINCIPLE 5: Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may be limited according to the quality of the candidate responses seen). GENERIC MARKING PRINCIPLE 6: Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or grade descriptors in mind. Science-Specific Marking Principles 1 Examiners should consider the context and scientific use of any keywords when awarding marks. Although keywords may be present, marks should not be awarded if the keywords are used incorrectly. 2 The examiner should not choose between contradictory statements given in the same question part, and credit should not be awarded for any correct statement that is contradicted within the same question part. Wrong science that is irrelevant to the question should be ignored. 3 Although spellings do not have to be correct, spellings of syllabus terms must allow for clear and unambiguous separation from other syllabus terms with which they may be confused (e.g. ethane / ethene, glucagon / glycogen, refraction / reflection). 4 The error carried forward (ecf) principle should be applied, where appropriate. If an incorrect answer is subsequently used in a scientifically correct way, the candidate should be awarded these subsequent marking points. Further guidance will be included in the mark scheme where necessary and any exceptions to this general principle will be noted. 5 ‘List rule’ guidance For questions that require n responses (e.g. State two reasons …): • The response should be read as continuous prose, even when numbered answer spaces are provided. • Any response marked ignore in the mark scheme should not count towards n. • Incorrect responses should not be awarded credit but will still count towards n. • Read the entire response to check for any responses that contradict those that would otherwise be credited. Credit should not be awarded for any responses that are contradicted within the rest of the response. Where two responses contradict one another, this should be treated as a single incorrect response. • Non-contradictory responses after the first n responses may be ignored even if they include incorrect science.

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 4 of 12 6 Calculation specific guidance Correct answers to calculations should be given full credit even if there is no working or incorrect working, unless the question states ‘show your working’. For questions in which the number of significant figures required is not stated, credit should be awarded for correct answers when rounded by the examiner to the number of significant figures given in the mark scheme. This may not apply to measured values. For answers given in standard form (e.g. a × 10n) in which the convention of restricting the value of the coefficient (a) to a value between 1 and 10 is not followed, credit may still be awarded if the answer can be converted to the answer given in the mark scheme. Unless a separate mark is given for a unit, a missing or incorrect unit will normally mean that the final calculation mark is not awarded. Exceptions to this general principle will be noted in the mark scheme. 7 Guidance for chemical equations Multiples / fractions of coefficients used in chemical equations are acceptable unless stated otherwise in the mark scheme. State symbols given in an equation should be ignored unless asked for in the question or stated otherwise in the mark scheme.

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 5 of 12 This mark scheme will use the following abbreviations: ; separates marking points / separates alternatives within a marking point () contents of brackets are not required but should be implied / the contents set the context of the answer R reject A accept (answers that are correctly cued by the question or guidance you have received) I ignore (mark as if this material was not present) AW alternative wording (where responses vary more than usual, accept other ways of expressing the same idea) AVP alternative valid point (where a greater than usual variety of responses is expected) ORA or reverse argument • underline actual word underlined must be used by the candidate (grammatical variants excepted) • MAX indicates the maximum number of marks that can be awarded • + statements on both sides of the + are needed for that mark • OR separates two different routes to a mark point and only one should be awarded • ECF error carried forward (credit an operation from a previous incorrect response)

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 6 of 12 Question Answer Marks 1(a)(i) any 2 of: low air pressure ; onshore wind ; hurricane / tropical cyclone / typhoon ; 2 1(a)(ii) any 2 of: flooding / port flooded ; (coastal) erosion ; damage to, property / structures / infrastructure / water damage / agriculture / crops ; 2 1(b)(i) 2 peaks, approx. same height + correct alignment with the time ; points plotted at midnight (1), midday (3) and midnight (5) at approx. the same height ; tide height at X 2 1(b)(ii) range is smaller ; 1 0 6 12 18 24

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 7 of 12 Question Answer Marks 2(a)(i) any 2 of: respiration ; movement or named, e.g. swimming ; digestion / other ; 2 2(a)(ii) any 2 of: (released) through decomposition ; by bacteria ; (may be) taken back into food chain / ref. to detritivores ; (return to the surface in nutrients in) upwelling ; incorporated (into chemical components) in the reef ; 2 2(a)(iii) 3300 – 720 – 2200 OR 2920 (lost) OR 380 ; 380 100 3300 × ; = 11.5(15)% ; OR 720 + 2200 OR 2920 ; ( ) 2920 100 88. 484 3300 × = OR 88.5 ; 100 – 88.48 (or 88.5) = 11.5(2) ; 3 2(b)(i) fourth ; 1 2(b)(ii) any 2 of: large, numbers / population, of (small) producers / algae ; (supports) smaller number of larger, organisms / consumers (in next level up) ; large number of, parasites /nematodes, living in tuna OR parasites / nematodes are very small organisms OR parasites / nematodes live inside the tuna ; 2 2(b)(iii) nematode bar will be narrower / smaller than the tuna bar ; 1

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 8 of 12 Question Answer Marks 2(c)(i) any 2 of: bones / skeleton ; DNA / RNA / nucleic acids ; ATP / ADP ; phospholipids ; 2 2(c)(ii) absorbed by algae / phytoplankton / producer ; (idea of ) passed along the food chain to the sea bream ; 2 2(c)(iii) not all of the sea bream is, eaten / consumed OR the bones are indigestable ; 1 Question Answer Marks 3(a) decrease(s) ; 1 3(b) 7.8 ; 1 3(c) any 3 of: increasing depth decreases temperature ; colder water holds more oxygen / allows a higher oxygen con-centration ORA ; increasing depth increases salinity ; increasing salinity reduces oxygen concentration ; 3 Question Answer Marks 4(a)(i) no Coriolis forces / Coriolis forces too weak ; 1 4(a)(ii) any 1 of: high wind shear ; water temperature not warm enough / water temperature below 26.5°C / 80°F / correct ref. to upwelling ; 1

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 9 of 12 Question Answer Marks 4(b)(i) any 4 of: evaporation / formation of water vapour / high humidity / moist air ; transfers (heat) energy from ocean to atmosphere ; energy stored in water vapour ; rises / convection ; (water vapour) condenses ; releases latent, heat / energy ; 4 4(b)(ii) absorb energy / reduces wave height / act as breakwater ; 1 4(c) any 2 of: increases / causes, erosion ; removes sand from shore ; moves sand around the shore ; ref. to organisms being disrupted ; 2 Question Answer Marks 5(a)(i) any 2 of: the number / amount of, species / types, of living organisms ; idea of, and (their) abundance ; idea of, genetic diversity ; 2 5(a)(ii) any 3 of: unstable / shifting, sands / substrate ; few species adapted to live there / few species can live there ; have to eat anything available / few producers / less food available ; species burrow to survive / ref. to infauna ; few / no suitable substrate for attachment ; few niches ; 3

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 10 of 12 Question Answer Marks 5(a)(iii) named predator-prey relationship + named parasitic relationship, e.g. nematodes and tuna ; plus any 3 of: predator, hunts / kills, and eats prey (quickly) ; parasite does not always cause death of host / (idea of) can recover from / have parasites removed (e.g. by cleaner fish) ; (idea of) parasite gains long-term advantage / nutrition ; host harmed (or named harm) + parasite benefits (or named benefit) ; predator will eat many prey + parasite infects 1 host (at each stage of its lifecycle) ; 4 5(b) mutualism / mutualistic ; plus MAX 3 of: both species benefit ; coral polyp receives, nutrients / food / sugars / carbohydrate ; coral polyp receives oxygen (from zooxanthellae) ; zooxanthellae receives, protection / a shelter ; zooxanthellae receives carbon dioxide (from coral polyp) ; 4

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 11 of 12 Question Answer Marks 6(a) (oceanic) trench ; 1 6(b) any 4 of: correct ref. to relative plate densities OR oceanic plate under, land / continental plate ; crust subducted ; (crust) melts ; magma pressure increases ; weakness in crust / lithosphere ; lava erupts ; solidifies (to create cone) ; builds up (until reaches the surface) ; 4 6(c) tsunami ; 1 Question Answer Marks 7(a) any 3 of: warm waters (within stated range of 16–35°C / 60–95°F) ; shallow ; clear water / low turbidity / low nutrient ; high light penetration ; high light intensity ; rocky substrate (for attachment) ; pH 8.1–8.5 ; 3 7(b) any 3 of: disease ; air exposure ; water pollution ; sedimentation / blocking coral polyps from feeding / blocking light / abrasion ; extreme weather example (hurricanes / severe storms) ; natural disaster (tsunami / earthquake) ; rising sea temperature ; acidification ; outbreak of, predators / COTS / crown of thorns starfish / coral eating fish / named coral eating fish ; 3

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2021 © UCLES 2021 Page 12 of 12 Question Answer Marks 7(c) any 3 of: core sampling / drilling ; coral banding ; geomorphological analysis ; carbon dating ; 3 Question Answer Marks 8(a) any 4 of: (idea of,) ocean warmer than land ; air over the ocean is warmer ; warm air rises ; creating low pressure area over ocean ; leaving space for dry air to move from above the land ; (dry) offshore wind occurs ; 4 8(b)(i) any 4 of: rainfall causes runoff ; reduces sea water density ; washes, nutrients / fertilizer / named toxin, into the ocean ; reduced pH / acidification (due to freshwater input) ; increases turbidity ; reduces salinity ; increased oxygen / dissolved gases ; temperature change ; 4 8(b)(ii) increased nutrients / carbon dioxide / named nutrients ; more photosynthesis / greater population of producers ; 2