| Date | May 2016 | Marks available | 3 | Reference code | 16M.1.SL.TZ0.2 |
| Level | Standard Level | Paper | Paper 1 | Time zone | Time zone 0 |
| Command term | Identify | Question number | 2 | Adapted from | N/A |
Question
Figure 3: A simplified diagram of the Lake Shergar area.
Figure 3
[Source: © International Baccalaureate Organization 2016]
The lake provides a water supply for the local population.
Outline why this lake may be considered an open system.
Identify two outputs from this lake.
With reference to Lake Shergar, explain what is meant by natural income.
With reference to the cattle in the area, explain how the maximum sustainable yield could be calculated.
Nitrates and phosphates from nearby farms may drain into the lake. Identify a strategy for managing this pollution at each of the following levels:
Markscheme
it exchanges matter and energy (with its surroundings).
[1 max]
water flow/river Nia
evaporation
infiltration/groundwater flow
fish/biota
water (supply for local communities)
hydropower /electricity /energy from the dam
oxygen from plants
heat
Award 1 mark for any two correct responses. No mark for only one correct response.
Accept any other reasonable suggestions.
Do not accept only ‘energy’ (as examples of matter and energy are required).
[1 max]
natural income is the annual growth/yield in natural capital /natural income is derived from natural capital;
natural income are marketable commodities produced by the lake / lake provides a yield or harvest of goods/services.
Example:
goods such as water for the village/crops/cattle
goods such as fish/water plants
services such as flood protection /power or electricity from dam.
Do not accept natural income as money/revenue for selling resources or definition of sustainable yield.
[1] for explaining natural income and [1] for providing one example.
[2 max]
it is the maximum rate that it can be exploited without depleting the stock;
for example calculating the annual gain in biomass (of the cattle/stock)/annual growth of the cattle minus death;
sustainable yield = (total biomass/energy at time t + 1) − (total biomass/energy at time t).
[2 max]
Do not credit use of same management strategy more than once.
Do not accept just ‘contour ploughing/creating barriers/filter water/legislation/change behaviour/clean up’ without explanation.
Do not accept use of natural/organic fertilizers or addition of limestone / calcium carbonate (which releases phosphates from the sediments).
[3 max]
Examiners report
The majority of candidates correctly answered this question.
Most candidates were able to clearly identify two outputs from the lake.
Responses varied widely. A common error included referring to natural income as monetary income. In some cases, no reference was made to the lake as requested.
Few candidates explained how maximum sustainable yield (MSY) could be calculated. Many candidates confused MSY with carrying capacity.
Responses varied widely with some candidates clearly identifying 3 correct strategies, however many responses lacked sufficient detail e.g. answers just stated ‘legislation’ or ‘clean up’.
Syllabus sections
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19M.2.SL.TZ0.6b:
Suggest a range of practical procedures that could be carried out to measure the abiotic and biotic impacts of an oil spill in an aquatic ecosystem.
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19M.1.SL.TZ0.11a:
Explain how the following land-based activities could have a damaging effect on marine ecosystems within the Coral Triangle: deforestation.
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19N.1.SL.TZ0.5:
With reference to information in the resource booklet, evaluate the sustainability of Canada’s management of the Large Ocean Management Area of the St Lawrence River estuary and Gulf of St Lawrence.
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15M.2.SL.TZ0.1c.ii:
Identify one possible pollution management strategy for Inle Lake in each of the categories in the table below.
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18N.2.SL.TZ0.5c:
Discuss strategies that can be used to improve the sustainability of food production systems.
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17M.2.SL.TZ0.4c:
To what extent are the concepts of net productivity and natural income useful in managing the sustainable harvesting of named resources from natural ecosystems?
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15M.2.SL.TZ0.1a.iii:
With reference to Figures 4 and 5, identify three environmental impacts that may occur as a consequence of human activities on and around Inle Lake.
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17M.2.SL.TZ0.6c:
The provision of food resources and assimilation of wastes are two key factors of the environment that determine its carrying capacity for a given species.
To what extent does the human production of food and waste each influence the carrying capacity for human populations?
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15M.2.SL.TZ0.1c.iii:
Explain how the use of fertilizers in agriculture may lead to hypoxic water in the areas shown in Figure 7.
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18M.1.SL.TZ0.10:
Explain how the protection of forests in Makira National Park may contribute to the conservation of the aquatic environment of MaMaBay.
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19N.1.SL.TZ0.4a:
Using Figure 11(b), estimate the highest concentrations of coliform bacteria (in units/100 mL) found in the St Lawrence River one day after the untreated sewage was released.
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19M.1.SL.TZ0.11b:
Explain how the following land-based activities could have a damaging effect on marine ecosystems within the Coral Triangle: agricultural activity.
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19M.1.SL.TZ0.8:
With reference to Figure 5, describe how loss of a coral reef ecosystem could impact a neighbouring seagrass community.
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19N.2.SL.TZ0.8b:
Explain how environmental indicators are used to assess sustainability.
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19N.1.SL.TZ0.3b:
With reference to Figure 9(a), outline how the round goby both positively and negatively affects the St Lawrence River ecosystem.
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19N.2.SL.TZ0.7c:
To what extent do the approaches and strategies of different environmental value systems improve access to fresh water?
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19N.2.SL.TZ0.6b:
Explain how ecological techniques can be used to study the effects of human activities on the biodiversity of a named ecosystem.
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19N.2.SL.TZ0.5c:
To what extent is pollution impacting human food production systems?
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19N.1.SL.TZ0.4c:
With reference to Figures 10, 11(a) and 11(b), describe a method to monitor the impact of the release of untreated sewage into the St Lawrence River ecosystem.
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18N.2.SL.TZ0.6c:
Discuss the consequences of changing global per capita meat consumption on the conservation of ecosystems and biodiversity.
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14M.2.SL.TZ0.5b:
Evaluate the use of biotic indices compared with direct methods of measuring pollution.
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15M.2.SL.TZ0.5a:
Outline two indirect methods that could be used to measure the impact on the river ecosystem of dead organic matter from the flooded vegetation and soils.
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15N.1.SL.TZ0.5c:
Apart from global warming and ozone-depletion, state one pollution problem that may affect a number of countries.
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16N.1.SL.TZ0.6a:
Define biochemical oxygen demand (BOD).
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16N.1.SL.TZ0.6c:
Suggest how the population growth curve for algae in Graph C would appear if the pollutant had been nitrates and phosphates from fertilizer run-off.
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18N.1.SL.TZ0.4a:
With reference to Figures 8(a) and 8(b), describe the changes in nutrient and oxygen content that occur after beaver dams are constructed. Include quantities in your response.
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17M.2.SL.TZ0.5b:
Explain how positive feedback mechanisms may influence the equilibrium of an aquatic ecosystem during the process of eutrophication.
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14N.2.SL.TZ0.3b:
Explain how three pollution management strategies may reduce eutrophication in agricultural areas.
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16N.2.SL.TZ0.4b:
Explain two factors which lead to a loss of marine (ocean) biodiversity.
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16N.2.SL.TZ0.1l:
Using evidence from the resource booklet, justify from an ecocentric viewpoint why the Husab Uranium Project should not be approved.
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17N.1.SL.TZ0.3c:
With reference to Figures 6(c), 7(a) and 7(b) explain the problems associated with land restoration in Iceland.
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18M.2.SL.TZ0.6b:
Explain how organic waste may be an effective fertilizer in terrestrial systems but a source of pollution in aquatic systems.
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19N.1.SL.TZ0.4b:
Outline an environmental problem that may result from the release of untreated sewage into a river.
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17M.2.SL.TZ0.5c:
Pollution management strategies may be aimed at either preventing the production of pollutants or limiting their release into ecosystems.
With reference to either acid deposition or eutrophication, evaluate the relative efficiency of these two approaches to management.
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16N.1.SL.TZ0.6b:
Outline how turbidity changes after the raw sewage discharge point in Graph B.
