Understanding Concepts and Terminology

• Aquatic food production systems: aquaculture, capture fisheries, aquatic species harvesting 1 mark
• Terrestrial food production systems: provision of food to a growing population 1 mark
• Aquatic pollution sources: wide range of parameters lowering water quality 1 mark
• Soil content, soil degradation, soil fertility 1 mark
• Sustainability of food production systems influenced by industrialization, fossil fuel use, mechanization, fertilizers, pesticides, acid deposition, tropospheric ozone, ozone depletion, eutrophication, dead zones, climate change 1 mark Relevant examples will be of pollution affecting food production NOT the other way round

Breadth in Addressing and Linking

• Range of pollutants/polluting activities: fertilizer use, emissions from combustion of fossil fuels, mining, waste disposal, etc. 1 mark
• Impacts on food production systems: aquaculture, terrestrial farming systems 1 mark
• Methods of limiting impacts: alternative sources, regulations, clean-up procedures 1 mark

Examples

• Food production systems
• Farming practices (aquatic and terrestrial)
• Impacts of pollutants/polluting activities
• Methods of limiting impacts 1 mark

Balanced Analysis

• Extent to which a range of pollution events are impacting, or being restored/prevented from impacting, a range of different food production systems 1 mark

Conclusion

• Consistent with and supported by analysis and examples given
• Example: 'Terrestrial FPSs are affected by a wider range of pollutants and polluting activities, thus aquatic FPSs show a greater potential for sustainable production feeding the fast-growing global population' 1 mark

9 marks max

Understanding Concepts and Terminology

• Acid deposition: wet (acid rain, fog, snow) and dry (gases, particulates) forms of pollution 1 mark
• Natural ecosystems: terrestrial (forests, grasslands) and aquatic (lakes, rivers) 1 mark

Causes

• Emissions of sulfur dioxide ($SO_2$) and nitrogen oxides ($NO_x$) from fossil fuel combustion 1 mark
• Other sources: volcanic activity, biological decay 1 mark

Effects

• Terrestrial ecosystems: soil acidification, nutrient leaching, damage to vegetation 1 mark

$$\text{Acid deposition} + \text{soil} \rightarrow \text{aluminum ions released} \rightarrow \text{toxic to plants}$$

• Aquatic ecosystems: lowered pH, loss of biodiversity, reproductive failure in fish 1 mark

$$\text{Acid deposition} \rightarrow \text{increased acidity of lakes/rivers} \rightarrow \text{death of aquatic life}$$

Examples

• Specific examples of affected ecosystems and species 1 mark Examples must be relevant and support the analysis

7 marks max

Primary pollution

• Is active upon emission of pollutant 1 mark
• Examples: carbon dioxide, sulphur oxides, ozone, lead, nitrates, phosphates, heat, light 1 mark

Secondary pollution

• Occurs when primary pollutants undergo some kind of physical or chemical change 1 mark
• Examples: nitrogen/sulphur oxides combining with water to form nitric acid/sulphuric acid/acid rain; nitrogen oxides/VOCs combining to form tropospheric ozone/photochemical smog 1 mark

Some pollutants (e.g. ozone/sulphur oxides) can be credited as both a primary and secondary pollutant but to gain credit for the latter there must be an identification of a primary pollutant from which it is derived. Do not accept eutrophication (e.g. toxic substances released from algal blooms) as example of secondary pollutant.

4 marks max