Cambridge A Level Marine Science 9693 — 2022 May/June Paper 1 · Variant 1

This document has 16 pages. Any blank pages are indicated. [Turn over Cambridge International AS & A Level DC (CE/FC) 301906/5 © UCLES 2022 * 2 6 1 1 7 2 6 4 2 7 * MARINE SCIENCE 9693/11 Paper 1 AS Level Theory May/June 2022 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 [ ].

2 9693/11/M/J/22 © UCLES 2022 BLANK PAGE

3 9693/11/M/J/22 © UCLES 2022 [Turn over Section A Answer all questions in this section. 1 Table 1.1 lists four environmental factors that affect the solubility of gases. Complete Table 1.1 by placing one tick in each row. Table 1.1 environmental factor increases gas solubility decreases gas solubility decreasing water temperature increasing water depth increasing salinity decreasing atmospheric pressure [2]

4 9693/11/M/J/22 © UCLES 2022 2 (a) Fig. 2.1 shows a yellowfin tuna and Fig. 2.2 shows a spotted dolphin. These are not to scale. Fig. 2.1 Fig. 2.2 (i) Label Fig. 2.1 to show the: • operculum • lateral line. [2] (ii) State two features common to all organisms in the phylum Chordata, that would be present in the embryos of both species. 1 … 2 … [2] (iii) Yellowfin tuna reproduce through external fertilisation. The fertilised eggs and larvae become part of the zooplankton. Explain the meaning of the term zooplankton. … … … … [2] (b) Groups of adult yellowfin tuna sometimes swim with groups of spotted dolphins. The adult yellowfin tuna swim just above the thermocline. Spotted dolphins swim at depths of up to 20 m in daylight. (i) Use this information to suggest why yellowfin tuna are sometimes found with spotted dolphins only in tropical regions. … … … … [2]

5 9693/11/M/J/22 © UCLES 2022 [Turn over (ii) Dolphin populations can be estimated using a modified form of mark-release-recapture. All dolphins seen on the first day (first sample) of monitoring along a transect in a specific area are photographed. The dolphins are identified by their dorsal fin size, scarring and dorsal fin notches or body markings, which are unique to each individual. Fig. 2.3 shows a dolphin with notches and scarring on its dorsal fin. Fig. 2.3 Individuals are again identified on the second monitoring day (second sample). The Lincoln index is then applied to this data. Discuss the limitations of this method for determining dolphin populations over a five-year period. … … … … … … [3] [Total: 11]

6 9693/11/M/J/22 © UCLES 2022 3 Fig. 3.1 shows the location of Madagascar. Tropic of Capricorn Madagascar 0 1000 miles equator Fig. 3.1 Fig. 3.2 shows the location of mangroves around the island of Madagascar. Cap St. Vincent land Tsiribihina River Ambanja Maintirano Mahajamba Bay Bombekota Bay Key mangrove rivers N 0 300 km 0 18 km 0 18 km Fig. 3.2

7 9693/11/M/J/22 © UCLES 2022 [Turn over (a) (i) Outline the conditions in Mahajamba Bay that make it suitable for the development of a mangrove forest. … … … … … … [3] (ii) Some mangrove species on Madagascar use the same method of reproduction as the red mangrove tree. Explain this method of reproduction and how it is an advantage to these mangrove trees. … … … … … … … … [4]

8 9693/11/M/J/22 © UCLES 2022 (b) Table 3.1 shows the changes in mangrove forest areas in different regions of Madagascar between 1975 and 2005. Table 3.1 change in mangrove forest area / km2 region 1975–1990 1990–2000 2000–2005 Bombekota Bay –66 –87 –68 Mahajamba Bay +1 –63 +14 coast of Ambanja +75 –12 +18 Cap St. Vincent –8 –11 –35 Tsiribihina River –32 –19 –83 (i) Use Table 3.1 to calculate the total changes in mangrove forest area between 1975 and 2005 in: Bombekota Bay … … coast of Ambanja … … [2] (ii) Suggest three reasons for changes in mangrove forest area in Madagascar over the period 1975 to 2005. 1 … … 2 … … 3 … … [3]

9 9693/11/M/J/22 © UCLES 2022 [Turn over (c) Coral reefs and seagrass beds are present off the west coast of Madagascar. Suggest one ecological impact of the loss of mangrove forest in Bombekota Bay and the impact this could have on the local human community. … … … … [2] [Total: 14]

10 9693/11/M/J/22 © UCLES 2022 4 (a) Describe how the processes of erosion and sedimentation cause the formation of a sandy shore. … … … … … … … … [4] (b) (i) Sandy shores act as a biological filter for sea water. Suggest two other services the sandy shore could provide. 1 … 2 … [2] (ii) Diatoms are part of the first trophic level on sandy shores. Describe the role of diatoms in the food chain. … … … … [2] [Total: 8]

11 9693/11/M/J/22 © UCLES 2022 [Turn over 5 Sea water is a mixture of water, salts and gases. (a) State the name of two salts found in abundance in sea water. … and … [1] (b) Fig. 5.1 shows a hydrogen atom and Fig. 5.2 shows an oxygen atom. Fig. 5.1 Fig. 5.2 (i) Explain how bonding occurs between hydrogen atoms and oxygen atoms in a water molecule. You may use diagrams in your answer. … … … … … … … … [4]

12 9693/11/M/J/22 © UCLES 2022 (ii) Explain how hydrogen bonds form between water molecules. You may use diagrams in your answer. … … … … … … [3] (iii) Sea ice is less dense than sea water, so it floats. Explain the importance to organisms of sea ice floating on sea water. … … … … [2] [Total: 10]

13 9693/11/M/J/22 © UCLES 2022 [Turn over Section B Answer all questions in this section. 6 Discuss the relationships formed between each of the following pairs of organisms. coral polyps and zooxanthellae … … … … copepods and marine fish … … … … manta rays and remora fish … … … … [6]

14 9693/11/M/J/22 © UCLES 2022 7 (a) Discuss plate tectonic theory and the evidence used to support the theory. … … … … … … … … … … … … … … [7]

15 9693/11/M/J/22 © UCLES 2022 (b) Explain the formation of the global ocean conveyor belt. … … … … … … … … … … … … … … [7] [Total: 14] [Turn over

16 9693/11/M/J/22 © UCLES 2022 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. 8 Explain the processes which replenish dissolved nutrients in sea water. … … … … … … … … … … … … … … … … … … … … [10]

This document consists of 14 printed pages. © UCLES 2022 [Turn over Cambridge International AS & A Level MARINE SCIENCE 9693/11 Paper 1 AS Level Theory May/June 2022 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 2022 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 2022 © UCLES 2022 Page 2 of 14 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 2022 © UCLES 2022 Page 3 of 14 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 2022 © UCLES 2022 Page 4 of 14 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 2022 © UCLES 2022 Page 5 of 14 Key Points  Refer to the Instructions for Examiners (marking scripts on-screen) 2021 booklet for details of all procedures.  As soon as you are able (usually about two days after the paper set date), please access the question paper and provisional mark scheme from the RM support portal. In conjunction with the provisional mark scheme, browse scripts in RM Assessor (scoris) and feed any issues or comments to your Team Leader.  The decisions of the Principal Examiner are final, and the final agreed mark scheme must be applied as intended by the Principal Examiner. If you are in any doubt about applying this mark scheme, consult your Team Leader by telephone or by email.  Please report any serious problems during marking to your Team Leader / Principal Examiner (details in the confidential package).  If you require technical support, please contact the RM Helpdesk. If you require administrative support relating to the examination process, please contact the CIE Examiner Helpdesk. For all queries relating to payment, please contact Cambridge Assessment Finance Division. Up-to-date contact details for each of these can be found in the Instructions for Examiners (marking scripts on-screen) 2021 booklet.  The schedule of dates is very important. It is essential that you meet the Batch 1 and Batch 2 deadlines. If you experience problems, you must contact your Team Leader without delay.  Mark strictly to the mark scheme. All marks awarded must relate directly to the mark scheme. However, always credit correct, relevant, science, even if it lies outside of the syllabus content. For answers not provided for in the mark scheme, give as far as possible equivalent marks for equivalent work. If in doubt, consult your Team Leader.  Never transfer marks allocated for one question item to another.  Where work has been crossed out, mark it when nothing else has been written.  Do not penalise grammatical constructions/spelling of words that are not in the syllabus, so long as the meaning is clear.  Credit should be given to all the candidate’s correct responses, wherever they have been written (including blank pages, around diagrams, etc.).  Additional materials may be attached and must be checked for candidates’ responses. Show that you have checked blank pages for answers by placing an annotation on each blank page. Do not use crosses or ticks for this purpose, unless the points are credited as part of a response to a specific question. In this instance, please use the On Page Comment tool to clearly annotate which question part the marks relate to.  If the candidate has left an answer blank, or has left a mark/comment that does not in any way relate to the question (for example ‘my dog is black’ or ‘----‘ or ‘can’t do’ or ‘?’) use the NR (No Response, #) option.  Award 0 marks for any attempt which does not earn credit. This includes copying out all / part of the question or any working that does not earn any marks (whether crossed out or not).

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 6 of 14  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 2022 © UCLES 2022 Page 7 of 14 Question Answer Marks 1 environmental factor increases gas solubility decreases gas solubility decreasing water temperature  increasing water depth  increasing salinity  decreasing atmospheric pressure  2 Question Answer Marks 2(a)(i) label line touching operculum ; label line touching lateral line ; 2 2(a)(ii) any 2 from: post-anal tail ; notochord ; dorsal neural tube ; pharyngeal slits ; 2 Accept operculum line to anywhere within this area Accept lateral line label to anywhere

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 8 of 14 Question Answer Marks 2(a)(iii) (primary) consumers ; plus any 1 of: limited mobility / swim weakly ; drift in oceanic currents ; 2 2(b)(i) thermocline, is shallow(er) / at 15–25 m (accept any stated value within the range) ; plus any 1 from: due to more heat energy OR warm / stable / less varied, conditions ; the dolphins are only found in shallow water / tuna swim in shallower areas ; 2 2(b)(ii) any 3 from: inaccuracies in identifying individuals second time / assumes no additional scarring has occurred ; photos, may be poor quality / of the other side of the dolphin ; migration / immigration / emigration may have occurred ; dolphins may be, disturbed / stressed, by the presence of boats (and learn to avoid) ; births / deaths may have occurred ; (Lincoln Index) assumes the effort (time taken) for the observations must be the same / AW ; (Lincoln Index) assumes all animals must be equally likely to be seen on the transect ; (Lincoln Index) assumes equal mixing of all those first observed / AW ; 3

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 9 of 14 Question Answer Marks 3(a)(i) any 3 from: tropical / sub-tropical / within named latitudes (30 degrees north / 30 degrees south) ; tidal ; saline ; freshwater input ; slow moving water / partly enclosed / low wave action / sheltered / calm waters / shallow ; sediment run-off from land ; fine grained sediments / sedimentation ; 3 3(a)(ii) any 4 from: viviparous ; seeds remain attached to parent tree ; providing water and nutrients ; germination occurs (while still attached) ; forming a propagule ; (propagule) drops into the ocean / water OR floats in the ocean ; carried by currents ; settles and (continues) growth ; propagules / plant spread to new areas ; seeds would not survive in sediment around trees / do not compete (for resources) with parent plant ; (seeds) do not have pneumatophores / cannot survive in anoxic sediment / would die if they absorbed saline water ; 4 3(b)(i) (Bombekota Bay) loses / decreases / – by, 221 km2 ; (coast of Ambanja) gains / increases / + by, 81 km2 ; 2

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 10 of 14 Question Answer Marks 3(b)(ii) any 3 from: (stated) change in land use (e.g. cleared for shrimp farm / tourism / housing / infrastructure) ; temperature change (increase / decrease) / climate change /global warming / rising sea level ; named natural disaster (e.g. hurricanes / cyclones / typhoons / tsunami) / more frequent storms ; over-harvesting of timber / deforestation ; replanting of mangroves ; parasites / diseases ; AVP ; 3 3(c) any 1 from: (ecological) allows build-up of sediment on coral reefs / sea grass beds ; damages / loses, nursery areas for, fish / marine species / habitat loss ; (human caused) pollutants increase ; reduces biodiversity ; reduces water quality ; AND (Impact) reduces, fish stock / income / catch, for fishermen / tourism ; OR reduced protection for shoreline / ORA (mangroves provide protection) ; AND increases coastal erosion / increased flooding / damage to (named) infrastructure ; 2

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 11 of 14 Question Answer Marks 4(a) any 4 from: (erosion is the) removal / movement, of sand particles away from source ; (particles from land) carried by wind or water ; (sand) particles sediment / settle / deposit ; (sedimentation occurs in) areas of low water, velocity / flow / speed ; sedimentation (rate) is higher than erosion (rate) ; 4 4(b)(i) any 2 from: (stated) economic / tourism ; protection of land ; maintain biodiversity / (turtle / bird) nesting sites / shore bird populations ; provides food (e.g. clams) / nursery area for some fish species ; 2 4(b)(ii) any 2 from: photosynthesis / photosynthetic / contain chlorophyll / producer ; use light (energy) to convert ; carbon dioxide and water ; to glucose (and oxygen) ; feed (primary) consumers / pass energy along food chain ; 2 Question Answer Marks 5(a) any 2 from: sodium chloride / magnesium sulfate / calcium carbonate ; 1 5(b)(i) any 4 from: covalent ; outer electron shells not full / (electron sharing) fills outer shells ; hydrogen requires 1 electron (to fill shell) / has 1 valence electron ; oxygen requires 2 electrons (to fill shell) / has 6 valence electrons ; share electrons ; two hydrogen atoms required for each oxygen atom ; 4

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 12 of 14 Question Answer Marks 5(b)(ii) any 3 from: (weak) electrostatic forces (develop) ; oxygen atom becomes (slightly), negatively charged / negative dipole ; hydrogen atom becomes (slightly), positively charged / positive dipole ; positive and negative charges attract ; 3 5(b)(iii) area for, mammals / birds, to rest on / escape predators ; thermal insulator / ORA / stops the whole water column from freezing ; (substrate for ) ice algae grow on underside ; 2 Question Answer Marks 6 MAX 2 from each section: coral polyp and zooxanthellae mutualism ; both organisms benefit ; coral obtains, food / nutrition / energy / carbohydrates / oxygen, from zooxanthellae ; zooxanthellae have, shelter / protection / carbon dioxide, from polyp ; copepods and marine fish parasitism ; the marine host / fish is harmed ; the parasite / copepod benefits ; manta rays and remora fish commensalism ; remora fish, benefit / transportation ; the manta rays are neither harmed nor helped ; 6

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 13 of 14 Question Answer Marks 7(a) any 7 from: (a) crust / lithosphere broken into plates ; (b) float on magma / mantle / asthenosphere ; (c) movement ; (d) due to convection current ; (e) caused / driven, (by differences in), temperature / density, (f) ongoing / continual / cyclical ; (g) jigsaw fit of continents ; (h) fossil records (at coasts) have same species ; (i) paleomagnetic stripes ; (j) geological matching / correlation (of rock formations) AW ; (k) similar species (alive now) found in different continents (l) named tectonic feature (ocean trench / sea floor spreading / subduction zone / volcanoes / mountain ranges / earthquakes (at plate boundaries) / hydrothermal vents) ; (m) named plate boundary, convergent (destructive) / divergent (constructive) / transform (conservative) 7 7(b) any 7 from: (a) warm water of Gulf Stream ; (b) heated at the equator / Caribbean / Gulf of Mexico / equatorial Atlantic ; (c) (warm water) flowing north ; (d) warms atmosphere when it reaches cold (northern) regions / ORA; (e) sea ice formation (in Arctic) leaves sea water saltier ; (f) water cools and sinks ; (g) due to higher density ; (h) pulls more (surface) water (north) ; (i) sinking water moves south ; (j) down to Antarctica ; (k) (Antarctic) circumpolar current around all oceans ; (l) travels into Indian ocean / warmed in the Indian Ocean ; (m) travels back to circumpolar region ; (n) rises as, warmer / less dense, water ; (o) returns to surface due to, mixing / upwelling ; (p) relevant reference to thermohaline current ; 7

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2022 © UCLES 2022 Page 14 of 14 Question Answer Marks 8 any 10 from: (a) run off ; (b) water, from rivers / flowed over land washed in from soil / fertiliser from fields / (weathering or erosion) rocks; (c) carries, nutrients / minerals ; (d) upwelling ; (e) carries nutrient rich water ; (f) from sea bed to the surface ; (g) tectonic activity / hydrothermal vents / underwater volcanoes ; (h) release gases / minerals ; (i) (gases from vents / volcanoes) dissolve ; (j) atmospheric dissolution / good description of atmospheric dissolution ; (k) excretion ; (l) decomposition / decay / bacterial action, of dead organisms OR marine snow ; (m) AVP ; 10