Cambridge A Level Marine Science 9693 — 2025 May/June Paper 1 · Variant 1

[Turn over Cambridge International AS & A Level DC (WW/CB) 342868/3 © UCLES 2025 This document has 16 pages. Any blank pages are indicated. MARINE SCIENCE 9693/11 Paper 1 AS Level Theory May/June 2025 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 [ ]. * 3 1 4 2 4 5 1 5 3 6 * ,










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2 9693/11/M/J/25 © UCLES 2025 Section A Answer all questions in this section. 1 (a) Carbon, hydrogen and oxygen are used to make many important biological molecules. Complete Table 1.1 by stating one other essential element required to make each biological molecule. Table 1.1 biological molecule essential element chlorophyll … DNA … skeletons and shells … [3] (b) Large biological molecules are made from smaller molecules. State the name of the two smaller molecules used to form lipids. 1 … 2 … [2] [Total: 5] * 0000800000002 * ,










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3 9693/11/M/J/25 © UCLES 2025 [Turn over 2 Fig. 2.1 shows kelp, a macroalga. A Fig. 2.1 (a) (i) State the name and suggest the function of the part labelled A. name … function … … [2] (ii) Describe the roles of kelp in the carbon cycle. … … … … … … [3] * 0000800000003 * ,










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4 9693/11/M/J/25 © UCLES 2025 (b) Fig. 2.2 shows part of a food web for a kelp ecosystem. sea otter starfish crabs prawns small fish kelp sea urchins Fig. 2.2 (i) State the name of one omnivore shown in Fig. 2.2. … [1] (ii) Suggest one benefit of being an omnivore. … … [1] (iii) Fig. 2.3 shows the biomass in arbitrary units (a.u.) of each population of organism in one food chain. kelp prawns starfish sea otter 1850 a.u. 325 a.u. 26 a.u. 1 a.u. Fig. 2.3 Calculate the percentage decrease in biomass between prawns and starfish. Space for working. …% [2] * 0000800000004 * ,










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5 9693/11/M/J/25 © UCLES 2025 [Turn over (iv) Sea otters can be infected by large numbers of parasites. Use Fig. 2.2 to draw a pyramid of numbers for the food chain of kelp, prawns, starfish and sea otter. Include a bar for parasites infecting the sea otters. [3] (c) State three ways kelp is of economic importance. 1 … 2 … 3 … [3] [Total: 15] * 0000800000005 * ,










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6 9693/11/M/J/25 © UCLES 2025 3 (a) Water is a solvent. (i) Draw a diagram to show the covalent bonding within a water molecule. Show the electron arrangement in the outer shells. [2] (ii) Describe how sodium chloride dissolves in water. … … … … … … [3] (iii) Define the term salinity. … … [1] (b) A student made 500 cm3 of artificial sea water by dissolving sodium chloride in pure water. State the mass of sodium chloride required to make a solution of 34 parts per thousand (ppt) in 500 cm3 of water. … g [1] * 0000800000006 * ,










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7 9693/11/M/J/25 © UCLES 2025 [Turn over (c) Describe the importance of ice floating to the marine ecosystem. … … … … … … [3] [Total: 10] * 0000800000007 * ,










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8 9693/11/M/J/25 © UCLES 2025 4 Fig. 4.1 shows a diagram of an estuary viewed from above. Fig. 4.2 shows how the salinity changes at location X in the estuary during a 24-hour period. K X Key land islands exposed at low tide equator 00:00 03:00 06:00 09:00 12:00 time / hours of the day salinity / ppt 15:00 18:00 21:00 00:00 10 5 0 15 20 25 Fig. 4.1 Fig. 4.2 (a) (i) Use Fig. 4.2 to calculate the salinity range for location X during the 24-hour period. … ppt [1] (ii) Suggest the reasons for the changes in salinity levels at location X in Fig. 4.1 during the 24-hour period. … … … … … … [3] * 0000800000008 * ,










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9 9693/11/M/J/25 © UCLES 2025 [Turn over (b) (i) Explain why location K is suitable for the development of a mangrove ecosystem. … … … … … … [3] (ii) Explain one adaptation of the red mangrove, Rhizophora mangle, to its tidal habitat. … … … … [2] [Total: 9] * 0000800000009 * ,










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10 9693/11/M/J/25 © UCLES 2025 5 (a) Primary productivity was continuously measured in two parts of an ocean in the southern hemisphere for a year. Fig. 5.1 shows the results. Jun Jul Aug Sept primary productivity / a.u. Oct Nov Dec Jan Feb month Mar Apr May polar temperate Fig. 5.1 (i) Define the term productivity. … … [1] (ii) Use Fig. 5.1 to describe how productivity differs between temperate and polar regions. … … … … [2] (iii) Light intensity is an abiotic factor which affects primary productivity. State two other changes in abiotic conditions that decrease primary productivity. 1 … … 2 … … [2] * 0000800000010 * ,










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11 9693/11/M/J/25 © UCLES 2025 [Turn over (b) Table 5.1 shows the neap tide heights in South Georgia in the Southern Ocean on one day. Table 5.1 time height / m 05:04 1.09 12:40 0.58 18:36 1.01 21:24 0.76 Suggest how the data would be different during a spring tide. … … [1] [Total: 6] * 0000800000011 * ,









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12 9693/11/M/J/25 © UCLES 2025 Section B Answer all questions in this section. 6 Rocky shore ecosystems contain different zones. Rocky shore organisms show different distribution and abundance across the zones. Fig. 6.1 shows this zonation. splash zone spring high tide spring low tide intertidal zone subtidal zone sea anemones brittle star mussels hermit crab limpets rockweed barnacles goose barnacles kelp sea cucumber sea urchins sea star Fig. 6.1 Explain why zonation occurs. … … … … … … … … … … … … … … … … [8] * 0000800000012 * ,









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13 9693/11/M/J/25 © UCLES 2025 [Turn over 7 Describe how underwater volcanoes form close to convergent plate boundaries. … … … … … … … … … … [5] * 0000800000013 * ,









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14 9693/11/M/J/25 © UCLES 2025 8 (a) Discuss the structure of a typical coral polyp. Describe the function of each structure. You can include a diagram. … … … … … … … … … … … … … … … … [8] * 0000800000014 * ,









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15 9693/11/M/J/25 © UCLES 2025 (b) Discuss the causes and effects of coral reef erosion. … … … … … … … … … … … … … … … … … … [9] [Total: 17] * 0000800000015 * ,









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16 9693/11/M/J/25 © UCLES 2025 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 * 0000800000016 * ,









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This document consists of 16 printed pages. © Cambridge University Press & Assessment 2025 [Turn over Cambridge International AS & A Level MARINE SCIENCE 9693/11 Paper 1 AS Level Theory May/June 2025 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 2025 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 2025 © Cambridge University Press & Assessment 2025 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 2025 © Cambridge University Press & Assessment 2025 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 2025 © Cambridge University Press & Assessment 2025 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 2025 © Cambridge University Press & Assessment 2025 Page 5 of 16 Annotations guidance for centres Examiners use a system of annotations as a shorthand for communicating their marking decisions to one another. Examiners are trained during the standardisation process on how and when to use annotations. The purpose of annotations is to inform the standardisation and monitoring processes and guide the supervising examiners when they are checking the work of examiners within their team. The meaning of annotations and how they are used is specific to each component and is understood by all examiners who mark the component. We publish annotations in our mark schemes to help centres understand the annotations they may see on copies of scripts. Note that there may not be a direct correlation between the number of annotations on a script and the mark awarded. Similarly, the use of an annotation may not be an indication of the quality of the response. The annotations listed below were available to examiners marking this component in this series. Annotations Annotation Meaning correct point or mark awarded incorrect point or mark not awarded information missing or insufficient for credit allow or accept incorrect or insufficient point ignored while marking the rest of the response contradiction in response, mark not awarded benefit of the doubt given error carried forward applied maximum mark reached benefit of doubt was considered, but the response was decided to not be sufficiently close for benefit of doubt to be applied

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 6 of 16 Annotation Meaning point already given power of ten error incorrect point or mark not awarded rounding error point has been noted, but no credit has been given or blank page seen response is too vague or there is insufficient detail in response , , marking point 1 or marking point a is awarded. Used to mark against a particular marking point from an extended answer MS used to highlight parts of an answer / incorrect idea / irrelevant to question used to highlight parts of an extended response / incorrect idea / irrelevant to question key point attempted / working towards marking point / incomplete answer / response seen but not credited / blank page seen ruler allows lengths to be measured multi-line overlay overlays graphs

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 7 of 16 This mark scheme will use the following abbreviations: ; separates marking points / alternative responses for the same marking point R reject the response A accept the response I ignore the response ECF error carried forward AVP any valid point / alternative valid point ORA or reverse argument AW alternative wording underline actual word given must be used by candidate (grammatical variants excepted) ( ) the word / phrase in brackets is not required but sets the context MAX indicates the maximum number of marks that can be given + AND statements on both sides of the + or AND are needed for that mark OR separates two different routes to a mark point and only one should be awarded

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 8 of 16 Question Answer Marks 1(a) substance components chlorophyll magnesium OR nitrogen; DNA phosphorous OR nitrogen skeletons and shells calcium OR phosphorus 3 1(b) fatty acids ; glycerol ; 2 Question Answer Marks 2(a)(i) holdfast ; any 1 from: (idea of) attach / secure/AW the kelp / macroalgae to the, seabed / seafloor/ rock / substrate ; OR withstand, current / wave action ; absorbing minerals / nutrients ; 2 2(a)(ii) any 3 from: absorb carbon (dioxide) during photosynthesis ; providing, food / carbon / glucose / organic matter / energy, passed along, food chains / through food webs ; releasing carbon (dioxide) from, respiration / decomposition OR carbon in faeces / carbon lost in egestion ; acts as carbon sink / stores carbon in tissues ; 3 2(b)(i) crabs ; 1 2(b)(ii) different, food sources / supplies available OR different/ wider range, of nutrients available ; 1

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 9 of 16 Question Answer Marks 2(b)(iii) 26 – 325 / 325  100 ; (–) 92 (%) ; 2 2(b)(iv) 5 closed rectangular bars approx. centrally positioned on top of each other in correctly named order ; bars for prawns, starfish and sea otter decreasing in width ; parasites bar (5th bar) is wider than sea otters and directly above sea otters bar ; 3 2(c) any 3 from: alginates / in food industry / food source / edible ; cosmetics / pharmaceuticals / medicines ; used as fertiliser ; (beds attract) tourism / named tourism ; food / nursery area for, economically important / harvested, fish / invertebrate species / (land) farm animals ; heavy metals extraction ; 3 kelp prawns starfish parasites sea otter

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 10 of 16 Question Answer Marks 3(a)(i) Ignore any other concentric circles around H and O correct sharing of electron pairs shown in oxygen and hydrogen atoms (must be within the overlapping area / on the overlapping lines) ; (only) 4 remaining outer electrons shown in oxygen AND no additional electrons in hydrogen ; 2 3(a)(ii) positive ions / Na+ / positive sodium ion, are attracted to, - oxygen / oxygen dipole ; negative ions / Cl- / negative chloride (ion), are attracted to, + hydrogen / hydrogen dipoles ; separates ions from the lattice / breaks the ionic, bond/ structure (in NaCl) / NaCl dissociates ; 3 3(a)(iii) concentration of (dissolved) salt in (sea) water OR concentration / mass, of dissolved salt ; 1 3(b) 17 (g) 1 3(c) (thermal) insulator ; so whole water column doesn’t freeze / maintains warmer temperature in sea below / organisms don’t freeze in the water ; habitat, for (named) organism(s) / algae OR algae / bacteria / protists, live /grow, in the ice / attached to bottom/ sides of ice / on the underside of the ice ; platform / place / surface, for / organisms, to rest / hide from predators OR a platform to hunt from / organisms hide below the ice / protection from predators ; releases minerals / nutrients ; 2

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 11 of 16 Question Answer Marks 4(a)(i) 10.5 (ppt) ; 1 4(a)(ii) any 3 from: due to rising AND falling tides ; salinity rises, as sea water enters the estuary / as sea water enters at high tide OR salinity drops as sea water leaves the estuary / sea water leaves at low tide ; as sea water leaves the estuary / at low tide, fresh water is, still entering / brought down the river, which dilutes the sea water / reduces salinity ; (heavy) rain (adds fresh water to the estuary so) reduces salinity / (high) evaporation increases salinity ; 3 4(b)(i) any 3 from: (mangroves) tolerant to salt water ; shallow ; (idea of) slow current / low or decreased wave action ; suitable substrate / muddy / sedimentation occurs (due to low current) ; located in a tropical / sub-tropical region OR it is a warm climate ; 3 4(b)(ii) any pair from: prop roots ; for stability / anchorage / prevent being washed away ; salt exclusion by roots ; to prevent (high level of) salt passing into the, mangrove / plant ; viviparous reproduction ; for young plant to survive in high salinity / seeds are buoyant to float / roots start to form, before detachment from parent / so they embed quickly (into new area or substrate) ; lenticels (on the roots) / (idea of ) aerial roots ; to, absorb / release, carbon dioxide / oxygen OR for gas exchange ; 2

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 12 of 16 Question Answer Marks 5(a)(i) rate of production of biomass (per unit, area / volume) ; 1 5(a)(ii) any 2 from: 1 polar only has one peak AND temperate has two peaks ; 2 polar (productivity), peaks / is high, in Nov / Dec AND temperate (productivity), peaks / is high, in Aug / Sept OR Feb / March ; 3 polar region reaches, a higher / the highest, productivity, than temperate region / ORA ; 4 polar productivity drops lower than the temperate / ORA ; 5 temperate has more productivity overall ORA OR temperate has productivity throughout the year AND polar productivity stops between Feb to Oct ORA ; 6 polar rate of productivity, increases / decreases, more rapidly than temperate ; 7 Oct–Jan polar has higher productivity than temperate ; 2 5(a)(iii) any 2 from: low / cold (water) / decrease in temperature / very high / hot temperature ; low, mineral/nutrient availability / concentration of named mineral ; low carbon dioxide concentration /lack of carbon dioxide ; AVP ; 2 5(b) range would be higher / greater OR higher high tide AND lower low tide ; 1

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 13 of 16 Question Answer Marks 6 any 8 from: 1 tides ; 2 (tides) create different physical / environmental / abiotic conditions (at different heights on the shore) ; 3 species have an, upper / lower, limit they can survive in ; 4 (idea of) organisms adapted to survive in a zone / organisms require different conditions to survive / organisms are adapted to a given or named condition ; 5 (more time in air, more chance of / adapted to) drying out / desiccation ; 6 changes in, exposure time in air / time submerged ; 7 changes / differences in light intensity ; 8 changes / differences in wave action ; 9 changes / differences in temperature ; 10 changes / differences in (water) depth / water pressure (at high / low tide) ; 11 predators control level of prey / organisms more susceptible to predation in some zones / predators are found more in some zones than others ; 12 difference in nutrient / food / prey, availability (in different zones) ; a interspecific competition / competition between species ; b intraspecific competition / competition within a species ; c competition for (named) resources ; 8

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 14 of 16 Question Answer Marks 7 any 5 from: 1 (denser) plate subducts / subduction zone ; 2 (idea of plate) comes into contact with the mantle ; 3 plate, is heated / melts ; 4 increases the magma (chamber) pressure ; 5 magma, forced out / ejected / erupts (at high pressure) ; 6 hot magma / molten rock is less dense rises ; 7 (hot magma / molten rock) solidifies when it meets the (cold) water ; 5

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 15 of 16 Question Answer Marks 8(a) MAX. 4 from structure names in bold (spelling must be correct or clear) plus any correct functions for named structures : 1 tentacles ; 2 to move food towards mouth ; 3 clear debris / sediment from near mouth ; 4 (tentacles contain) nematocyst ; 5 stinging cells / nematocysts, capture food / capture zooplankton / prey; 6 (stinging cells) as protection from predators ; 7 mouth / anus ; 8 ingests food OR removal of waste ; 9 stomach digests food ; 10 calyx / calcium carbonate, cup ; 11 (hard structure / skeleton / basal / base plate) to attach polyp (to reef / substrate) ; a (polyp retracts into calyx / theca) for support / protection ; b theca ; c walls of the calyx ; d basal / base (of calyx), plate ; e AVP ;; 8

9693/11 Cambridge International AS & A Level – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 16 of 16 Question Answer Marks 8(b) any 9 from: 1 water temperature rise ; 2 acidification / reduced pH ; 3 prevents / reduces, formation of (calcium carbonate) skeleton OR dissolves the calcium carbonate skeleton ; 4 (water temperature rise/ acidification/ named pollution can lead to) coral bleaching / zooxanthellae leave ; 5 storms / hurricanes ; 6 (storms / hurricanes) breaks pieces of coral off ; 7 sediments cause abrasion ; 8 (sediments) blocks mouth of polyp ; 9 (blocked mouth) reduces feeding ; 10 increased turbidity ; 11 sewage / oil / plastic / organic / toxins, pollution ; 12 reduced light availability ; a (increased turbidity / reduced light availability / less polyps) reduces, photosynthesis / productivity ; b stated, tourist / human, activities / divers touching or standing on corals / boat hitting them /anchors dropped on them / dynamite fishing / fishing nets / building materials / building infrastructure ; c bioerosion / described example ; d disease ; e coral / polyp death (leads to erosion) ; f reduces biodiversity / loss of food source (for non human organisms) / affects nursery or breeding grounds / ref. to disrupted food chains / habitat loss ; g reduction, in diving / tourism / affects fisheries / (potential) source of medicines ; h (more) erosion of land / less shore protection / loss of breakwater ; i AVP ; 9