Question
Identify two abiotic resources found in each of the following:
(i) continental shelf areas
(ii) ocean floor deposits.
Explain three consequences of oil pollution in oceans.
Examine the effects of the loss of coral reefs and mangrove swamps.[10]
▶️Answer/Explanation
Markscheme
(i) Award 1 mark for each valid resource identified, for example, placer deposits, oil and natural gas.
(ii) Award 1 mark for each valid resource identified, for example, manganese nodules, zinc, phosphates, sulphates, copper, lead, silver.
Possible consequences include:
- reduction in biodiversity
- declining ecological and/or economic productivity
- costs of clean-up operations
- social costs such as loss of livelihoods (short- and long-term unemployment)
- political costs such as after Deepwater Horizon.
Credit other valid consequences.
Award 1 mark for the description or example of each consequence and 1 mark for each explanation.
It is likely that most answers will refer to the possible causes of loss of coral reefs and mangroves as a first step to examining the effects of such loss.
The consequences of the loss of coral reefs are:
- erosion of coastlines
- loss of fish habitats (occupying less than 0.25% of the marine environment, they nevertheless shelter more than 25% of all known fish species)
- loss of biological and economic productivity
- loss of biodiversity
- loss of breeding and feeding grounds for fish
- economic and social loss to people who depend on fishing and/or coral reef tourism/diving.
Some of these effects are similar in the case of mangrove swamps.
In addition, a loss of mangroves may reduce the amount of available food and fuel, building materials and medicine. Mangroves also act as natural filters, absorbing nutrients from farming and sewage disposal.
Both coral reefs and mangroves protect coastlines by absorbing some wave energy, especially during storms such as hurricanes (tropical cyclones). The dense interlocking roads of mangroves help to stabilize shorelines and prevent erosion.
The loss of coral reefs and mangroves is not entirely negative. Removing them may improve navigation. Material eroded from coral reefs can accumulate to form attractive (and economically important) white-sand beaches. The destruction of mangrove swamps may allow for the construction of hotels, harbours and marinas.
Answers accessing markbands E/F should include the consequences of both coral and mangrove loss. Examples would be expected for bands E and F.
Marks should be allocated according to the markbands.
Examiners report
Few candidates had difficulty with this question.
Few candidates had difficulty with this question although it was not always easy for examiners to decide exactly where one consequence ended and the next began.
Responses tended to spend far too long describing causes (not required by the question) and too little time on effects and their consequences. Relatively few responses acknowledged any possible positive effects.
Question
(i) Define the term littoral drift (longshore drift).
(ii) Briefly describe one named feature caused by littoral drift.[4]
Explain the formation of two ocean floor landforms associated with volcanic or tectonic activity.[6]
“The loss of coral reefs is not just a local concern.” Discuss this statement.[10]
▶️Answer/Explanation
Markscheme
(i) The transport/movement of sediment along a coast [1 mark] by wave action/swash and backwash [1 mark]. Credit alternative phrasing.
(ii) Accept spits, bars, tombolos, cuspate forelands, beach cusps, drift-aligned beaches as the named feature. There should be a brief description of the chosen landform eg, a spit [1 mark] is a ridge of shingle that is attached to the mainland at one end [1 mark].
Features include underwater volcanoes, black smokers, trenches, transform faults, mid-ocean ridges and rifts, seamounts, guyots. The explanation should refer to either processes at divergent boundaries (upwelling magma and sea floor spreading) and/or
processes at subduction zones.
In each case, award up to [2 marks] for identification and description of the land forms and up to [2 marks] for explanation of its formation (maximum [3 marks]).
For example, an ocean trench [1 mark] is a very deep area of water parallel to the coast [1 mark] where one plate subducts under another [1 mark].
Economic and environmental issues can be investigated at both the local and other scales, for instance coral reefs have global biological importance in terms of high biodiversity, potential for medicine, while locally coral reefs also protect coasts by absorbing the strength of hurricanes and tropical storms. Economically they are important breeding grounds for fish and support local incomes, while globally coral reefs can be used to stimulate international tourism in visiting coral reefs. A local issue could include income generated from activities on coral reefs or that use coral eg, souvenirs, jewelry etc.
To achieve band D, responses will describe a few concerns probably at one scale only.
At band E, expect either a more detailed range of issues (concerns) such as economical/social/environmental, local and global, positive and negative or some explicit discussion of the statement (might contrast local/economic concern with global/environmental concern).
At band F, expect both.
Marks should be allocated according to the markbands.
Examiners report
The definition of littoral drift was generally well understood. Many candidates were able to identify a feature caused by littoral drift, such as spit or tombolo, but often did not describe the feature, choosing instead to explain its formation.
There was sound knowledge of the landforms associated with volcanic or tectonic activity, but the explanation of their formation was often not developed.
There were some very strong answers about coral reefs and generally no overall problems with interpreting this question. A lot of attention was given to the ecological impacts. Many answers tended to be rather descriptive, or tended to focus on local rather than global issues, with limited discussion of the statement.
Question
State two causes of a negative change in sea level.[2]
Briefly describe one landform associated with an advancing coast.[2]
Using examples, explain two effects of the oceanic conveyor belt on different places.[6]
“The loss of coral reefs has more serious effects than the loss of mangrove swamps.” Discuss this statement.[10]
▶️Answer/Explanation
Markscheme
Sea level fall [1]
Uplift of land [1]
Accept other valid terminology.
Award [1] for a named landform and [1] for description.
Possibilities include:
- relict platform
- raised beaches
- sandbar
- spit
- saltmarsh
- tombolo.
For example: An abandoned cliff / stack [1] is a former marine cliff now above the high tide level [1].
Award [1] for each valid effect and a further [2] for development/exemplification.
The oceanic conveyor belt brings warm water [1] into high latitudes in the North Atlantic [1] causing temperatures, evaporation and rainfall to be higher in this region [1].
In other regions, such as Antarctica [1], the oceanic conveyor belt causes the uplift/mixing of colder water with surface water, leading to an increase in nutrients in the upper water [1], thereby supporting a rich marine life, and, potentially, fisheries [1].
Consequences of the loss of coral reefs include: erosion of coastlines, loss of fish habitats and biodiversity (they shelter more than 25 % of all known fish species), loss of economic productivity and livelihoods for people who depend on fishing and/or coral reef tourism/diving.
In addition to biodiversity loss, the removal of mangroves may reduce the amount of available food, fuel, building materials and medicine for local societies. Mangroves also act as natural filters, absorbing nutrients from farming and sewage disposal. The dense interlocking roads of mangroves help to stabilize shorelines and prevent erosion.
Good answers may provide a structured discussion of different types of effect/impact according to scale (local/global issues), or human and physical effects. Another approach might be to discuss the onshore context of mangroves and the offshore context of reefs, thus reaching a judgement on the severity of loss for local people (relatively more are affected by mangrove loss). Another approach might be to discuss how coral reefs and mangroves both protect coastlines by absorbing some wave energy, especially during storms such as hurricanes (tropical cyclones).
At band D, expect a description of some effects/impacts of coral and mangrove loss (do not expect balance).
At band E, expect either a more detailed explanation of some severe effects of coral and mangrove loss (do not expect balance) or a structured discussion of the statement.
At band F, expect both of these elements.
Marks should be allocated according to the markbands.