Cambridge A Level Marine Science 9693 — 2024 May/June Paper 1 · Variant 1

This document has 16 pages. Any blank pages are indicated. [Turn over Cambridge International AS & A Level MARINE SCIENCE 9693/11 Paper 1 AS Level Theory May/June 2024 1 hour 45 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 [ ]. * 7 0 2 7 6 1 8 4 2 3 * DC (LK/CB) 329252/5 © UCLES 2024

2 9693/11/M/J/24 © UCLES 2024 Section A Answer all questions in this section. 1 Fig. 1.1 shows an atom of calcium. Fig. 1.1 (a) (i) Complete Table 1.1 with the names of the particles found in the nucleus and the charge of each type of particle. Table 1.1 name of particle charge of particle [2] (ii) Marine organisms use dissolved calcium salts for production of bones and shells. State the name and formula of one calcium salt commonly used by marine organisms. name … formula … [1] (iii) Explain the role of hydrogen bonding as sodium chloride dissolves in water. … … … … … … … … [4]

3 9693/11/M/J/24 © UCLES 2024 [Turn over (b) (i) The density of water changes as it freezes. Explain the changes that occur as water freezes. Include kinetic particle theory in your answer. … … … … … … [3] (ii) Calculate the volume of a mass of water of 14 863 g and a density of 1022 kg m–3. Show your working. … m3 [2] [Total: 12]

4 9693/11/M/J/24 © UCLES 2024 2 Fig. 2.1 shows an ascidian and Fig. 2.2 shows a reef shark. Both organisms are in the phylum Chordata. NOT TO SCALE Fig. 2.1 Fig. 2.2 (a) (i) State two features both organisms have in common during their early development. 1 … 2 … [2] (ii) On Fig. 2.2, label on the reef shark one visible feature typically found only in cartilaginous fish. [1] (b) (i) The binomial name of the blacktip reef shark is Carcharhinus melanopterus. Complete Table 2.1 with the classification for the blacktip reef shark. Table 2.1 group classification for the blacktip reef shark domain Eukarya … Animalia phylum Chordata class Chondrichthyes order Carcharhiniformes family Carcharhinidae … … species … [2]

5 9693/11/M/J/24 © UCLES 2024 [Turn over (ii) Shark species have a large amount of lipids in their liver to provide buoyancy. State the names of the molecules which combine to form lipids. … and … [1] (iii) Sharks use the ion PO4 3–. Give the name of PO4 3– and state one function of this ion in the shark. name … function … [2] (c) Some sharks are predators of ascidians. Some ascidians have a mutualistic species of bacteria living in their tissues. The bacteria produce a toxin. The toxin is only harmful to predators. Suggest how this relationship benefits the ascidians and the bacteria. … … … … [2] [Total: 10]

6 9693/11/M/J/24 © UCLES 2024 3 (a) Describe how weathering and erosion give rise to the morphology of a rocky shore. weathering … … … … erosion … … … … [4] (b) Muddy estuaries have high sedimentation rates. Red mangrove propagules settle in muddy areas. Describe three root adaptations that allow the red mangrove to survive the muddy conditions. 1 … … 2 … … 3 … … [3]

7 9693/11/M/J/24 © UCLES 2024 [Turn over (c) Fig. 3.1 shows the global loss of mangrove forests between 2000 and 2015. 2000 – 2005 mangrove loss / km2 0 500 1000 1500 2000 2005 – 2010 year natural human-caused 2010 – 2015 Key Fig. 3.1 (i) Suggest two different causes of natural mangrove loss. 1 … 2 … [1] (ii) Suggest two different causes of mangrove loss due to human activity. 1 … 2 … [1] (iii) Calculate for the period 2000 – 2005 the loss of mangrove due to natural causes as a percentage of the human‑caused loss. Give your answer to three significant figures. Show your working. … % [3] [Total: 12]

8 9693/11/ M/J/24 © UCLES 2024 4 (a) Fig. 4.1 shows a world map. Fig. 4.1 On Fig. 4.1, label the Pacific Ocean and the Southern Ocean. [1] (b) Fig. 4.2 shows the relationship between temperature and depth for one area of ocean in the northern hemisphere during four months of the year. 0 2 4 6 8 10 temperature / °C depth / m Mar 12 14 16 20 40 60 80 100 Jul Nov Aug Fig. 4.2 (i) Explain how Fig. 4.2 shows that the data were collected from a temperate region and not a tropical or polar region. … … … … … … … … [4]

9 9693/11/M/J/24 © UCLES 2024 [Turn over (ii) Use Fig. 4.2 to state the month in which the water density is highest at 20 m depth. … [1] (iii) Explain how and why primary productivity differs between March and August. … … … … … … … … [4] (iv) State the word equation for photosynthesis. … [1] [Total: 11]

10 9693/11/M/J/24 © UCLES 2024 Section B Answer all questions in this section. 5 Coral polyps have two methods of obtaining nutrition. Describe and explain both methods. … … … … … … … … … … … … … … … … … … … … [10]

11 9693/11/M/J/24 © UCLES 2024 [Turn over 6 Exposure time in air, dissolved oxygen concentration and competition are factors affecting the distribution and abundance of organisms in the different zones on a rocky shore. Explain how these three factors affect the distribution and abundance of organisms in the different zones on a rocky shore. … … … … … … … … … … … … … … … … … … [9]

12 9693/11/M/J/24 © UCLES 2024 7 Fig. 7.1 is a world map. Greenland ice sheet east coast of Australia Fig. 7.1

13 9693/11/M/J/24 © UCLES 2024 (a) Fig. 7.1 shows the location of the Greenland ice sheet. The global ocean conveyor belt is the constantly moving system of deep and surface water ocean circulation. Some scientists believe the global ocean conveyor belt is slowing down due to the melting of the Greenland ice sheet. Suggest why the melting of the ice sheet may slow down the global ocean conveyor belt. … … … … … … … … … … … … [6] (b) Fig. 7.1 shows the east coast of Australia. Describe the effects of El Niño on the east coast of Australia. … … … … … … … … … … [5] [Total: 11]

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16 9693/11/M/J/24 © UCLES 2024 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 Cambridge Assessment. Cambridge Assessment is the brand name of the University of Cambridge Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge. BLANK PAGE

This document consists of 16 printed pages. © Cambridge University Press & Assessment 2024 [Turn over Cambridge International AS & A Level MARINE SCIENCE 9693/11 Paper 1 AS Level Theory May/June 2024 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 2024 series for most Cambridge IGCSE, Cambridge International A and AS Level and Cambridge Pre-U components, and some Cambridge O Level components.

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 2 of 16 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 descriptions 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 2024 © Cambridge University Press & Assessment 2024 Page 3 of 16 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 2024 © Cambridge University Press & Assessment 2024 Page 4 of 16 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 2024 © Cambridge University Press & Assessment 2024 Page 5 of 16 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 2024 © Cambridge University Press & Assessment 2024 Page 6 of 16 Question Answer Marks 1(a)(i) Name of particle Charge of particle proton +1 / positive / + neutron 0 / neutral 2 1(a)(ii) calcium carbonate ; CaCO3 ; 1 1(a)(iii) any 4 from: (in water molecule) oxygen is slightly negatively charged / hydrogen is slightly positively charged / water is, polar (molecule) / dipolar / has a dipole ; Cl – / Na+ OR Cl ion / chloride, is negative OR / Na ion / sodium ion, is positive / because chloride / chlorine atom gains an electron from the sodium ion OR because sodium loses an electron to the chloride ions ; Cl – and hydrogen are attracted / hydrogen surrounds Cl – (to each other) / OR Na+ and oxygen are attracted (to each other) ; separates from the lattice / breaks the ionic bond (in NaCl) / NaCl dissociates ; e.g. of diagram for MP’s 2 and 3, and if they had + or - on the oxygen or hydrogen, they would also get MP1 4

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 7 of 16 Question Answer Marks 1(b)(i) any 3 from: (water cools so) molecules / particles, lose kinetic energy / move slower ORA ; (slower movement) allows formation of more hydrogen bonds between water molecules ; (hydrogen bonds) cause molecules to be, further apart / spread further apart, (than in the liquid state) ; ice is less dense so ice floats (on water) OR less molecules per unit volume so floats ; 3 1(b)(ii) 14.863 ÷ 1022 OR 14863 ÷ 1022000 ; 0.01454 / 0.014543 / 0.0145431 (m3) ; 2 Question Answer Marks 2(a)(i) any 2 from: post-anal tail ; notochord ; dorsal neural tube ; pharyngeal slits ; 2 2(a)(ii) 1 gill slits

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 8 of 16 Question Answer Marks 2(b)(i) group classification for the reef shark domain Eukarya kingdom Animalia phylum Chordata class Chondrichthyes order Carcharhiniforms family Carcharhinidae genus Carcharhinus species melanopterus 2 2(b)(ii) fatty acid(s) + glycerol ; 1 2(b)(iii) phosphate (ion) ; nucleic acid(s) / DNA / RNA / bones / skeletal structure / teeth ; 2 2(c) reduces chance of being eaten / reduce predation of ascidians / protection from, predators / sharks ; bacteria receive a named benefit; 2

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 9 of 16 Question Answer Marks 3(a) (weathering) is the breaking down of rocks into (smaller sizes) ; from, high/forceful, waves / constant wave action / drying and wetting / salt crystallisation in fissures / freeze fracture (above the splash zone) / chemical / acid rain / biological ; PLUS max. 3 from: (erosion) is the, transport/movement, of substrate (to a new location) ; by wind / water / waves / gravity ; low rates of erosion due to size of rocks / small pieces move with a smaller force ; erosion keeps rocky shores free of sediment / erosion (rate) is greater than sedimentation (rate) ; 4 3(b) thick / large / deep / cage like, prop root for stability ; gas exchange, in aerial roots ; salt exclusion during water uptake / filter out salt ; 3 3(c)(i) any 2 from: storm / hurricanes ; disease / parasites ; tsunamis ; fires ; being eaten ; erosion of, substrate / mud / coast ; invasive / alien, species ; 1

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 10 of 16 Question Answer Marks 3(c)(ii) any 2 from: over harvesting / deforestation OR (cut down,) for building materials / firewood ; (clearing for,) building land / aquaculture / shrimps farms / tourism infrastructure / infrastructure / housing ; climate change / global warming ; sea level rises ; named pollution ; eutrophication ; 1 3(c)(iii) 1200  1900 ;  100 = 63.15789 ; 63.2 (%) ; 3 Question Answer Marks 4(a) 1 Pacific ocean anywhere within the marked area. Southern ocean anywhere within the marked area.

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 11 of 16 Question Answer Marks 4(b)(i) any 4 from: 1 tropical temperature would have higher (surface) temperature OR polar temperature would be lower / tropical or polar, temperature changes little through the year ORA ; 2 August / max., (surface) temperature 14 °C OR March / lowest, (surface) temperatures do not drop below 4.5 °C / (surface) temperature range is 9.5 °C ; 3 lack of thermocline in March / large thermocline in August ; 4 (lack of thermocline in March) due to winter, mixing / turbulence / storms OR (large thermocline in August) due to stable (warm) weather ; 5 definite seasons shown (in graph) due to the large change in the thermocline (position) / thermocline (position) in tropical regions, don’t change significantly / August thermocline is similar to tropical thermocline ; 6 because polar region does not develop a (significant) thermocline / March thermocline is similar to polar thermocline; 4 4(b)(ii) March ; 1

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 12 of 16 Question Answer Marks 4(b)(iii) productivity, highest in March / lowest in August (no MP for this statement) any 4 from: 1 productivity is the rate of production of biomass ; 2 high nutrient availability / ref. to upwelling in spring OR nutrients used over summer so few available in August ; 3 (nutrient availability) due to high winter runoff ; 4 light availability increasing for more photosynthesis ; 5 fewer storms improve water clarity ; OR productivity, highest in August / lowest in March (no MP for this statement) any 4 from: 6 productivity is the rate of production of biomass ; 7 (primary) productivity is determined by rate of photosynthesis ; 8 temperature cold in March, so less photosynthesis ORA ; 9 fewer hours of sunlight in March, so less photosynthesis ORA ; 10 light intensity less in March, so less photosynthesis ORA ; AVP ; 4 4(b)(iv) carbon dioxide + water → glucose + oxygen ; 1

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 13 of 16 Question Answer Marks 5 any 10 from: 1 zooxanthellae ; 2 symbiotic / live in the corals (tissues) / mutualism ; 3 (zooxanthellae) are photosynthetic ; 4 (corals found in) shallow waters to gain sunlight / zooxanthellae use light energy for photosynthesis ; 5 produce glucose for the polyp / excess glucose is released ; 6 stinging cells / nematocyst / cnidoblast / cnidocyte ; 7 (nematocyst in or on) tentacles ; 8 fire out barb (into prey) ; 9 contains toxin ; 10 (toxin) which, paralyses / stuns / immobilises, prey ; 11 (prey) passed through the mouth and into stomach for digestion ; 12 for coral polyp to, absorb / use ; 13 AVP ; 10

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 14 of 16 Question Answer Marks 6 1 naming any 2 zones from splash zone, upper shore / zone, middle shore / zone or lower shore / zone ; 2 organisms cannot survive outside of their range of tolerance of (named) abiotic factors ; 3 ref. to, vertical zonation / horizontal bands ; 4 abundance OR distribution increases down the shore/biodiversity increases down the shore ORA ; 5 reference to, (named) animal, moving to rock pools, for gas exchange / prevent drying out / desiccation OR reference to (named) animal moving, under macroalgae / into crevices, to prevent drying out / desiccation ; At least 1 from: exposure time in air: 6 higher zones have greater exposure to air / less water coverage ORA ; 7 (higher zones) longer in air gives greater risk of desiccation / organisms have to be adapted to desiccation ORA ; 8 higher zones have a greater range of temperatures / more temperature fluctuations ORA ; 9 named adaptation to being out of the water e.g. shell closure to trap water or migrate with the tide ; 10 ref. to spring and neap tide range differences ; 11 named linked examples (mussel, limpet, macroalgae, barnacles, crab) ; 12 reference to diurnal tides / being covered / uncovered during a day (twice a day) ; 9

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 15 of 16 Question Answer Marks 6 At least 1 from: dissolved oxygen concentration: (a) (during high tide) dissolved oxygen (concentration) is high due to, wave action / crashing waves ; (b) organisms extract oxygen from the water (rather than air) ; At least 1 from: competition: (c) explanation of interspecific competition ; (d) explanation of intraspecific competition ; (e) correct ref. to resource competed for e.g. location, space, light, food / nutrient availability ; (f) harsh conditions in splash zone, so little competition / favourable conditions in lower or middle so a lot of competition ; Question Answer Marks 7(a) any 6 from: 1 land ice / ice sheet, is fresh water ; 2 lowers / reduces, density (of seawater) ; 3 (so it) floats on top of the ocean water ; 4 reduces evaporation of the salt water ; 5 salinity of surface water does not increase as much; 6 takes longer for salt water to become dense enough to sink / water sinks more slowly / reduces sinking of seawater / reduces downwelling / reduces movement of water by convection / convection currents reduced ; 7 (downwelling or sinking water) is the driving force (for the conveyor belt) / stops pushing water through the cycle / does not push deep water south ; 8 (BUT) melted ice water will be cold(er) ; 9 which is more dense ; 10 so (may still) sink ; 6

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2024 © Cambridge University Press & Assessment 2024 Page 16 of 16 Question Answer Marks 7(b) any 5 from: 1 increased temperature / warmer water / increased ocean heat (western Pacific) ; 2 reduced / stopped, winds blowing across the Pacific to Australia OR reduced / stopped Easterly winds OR increased, Westerly winds / winds blowing to the east ; 3 decreased rainfall / drier / droughts ; 4 reduces, fish catch / fish population OR fish migrate deeper or to cooler regions ; 5 reduced crops / less profit for farmers or fisherfolk / less food (for the population) ; 6 (increased) risk of, forest / bush, fires ; 7 (increased) coral bleaching ; 8 (increased) death of coral polyps ; 9 decreased biodiversity on coral reefs ; 10 fewer, cyclones / hurricanes / typhoons ; 11 increased frost ; 12 higher air pressure / high pressure system ; 5