inorganic plant nutrients (nitrates and Sources of marine pollution should phosphates), toxic metals, synthetic include rivers, pipelines, atmosphere and compounds, suspended solids, hot activities at sea (operational and water, oil, radioactive pollution, accidental discharges). pathogens, light, noise and biological The role of positive and negative pollutants (invasive species). feedback in the process of eutrophication A wide range of parameters can be used should be covered. Coastal to directly test the quality of aquatic eutrophication can lead to red tide systems, including pH, temperature, blooms. suspended solids (turbidity), metals, With respect to measuring aquatic nitrates and phosphates. pollution, a polluted and an unpolluted Biodegradation of organic material site (for example, upstream and utilizes oxygen, which can lead to anoxic downstream of a point source) should be conditions and subsequent anaerobic compared. decomposition, which in turn leads to International-mindedness: formation of methane, hydrogen sulfide and ammonia (toxic gases). Countries with limited access to clean Biochemical oxygen demand (BOD) is a water often have higher incidences of measure of the amount of dissolved water-borne illnesses. oxygen required to break down the organic material in a given volume of Theory of knowledge: water through aerobic biological activity. BOD is used to indirectly measure the A wide range of parameters are used to amount of organic matter within a test the quality of water and judgments sample. are made about causes and effects of Some species can be indicative of water quality—how can we effectively polluted waters and can be used as identify cause–effect relationships, given indicator species. that we can only ever observe A biotic index indirectly measures correlation? pollution by assaying the impact on species within the community according to their tolerance, diversity and relative Connections: abundance. Eutrophication can occur when lakes, ESS: Terrestrial food production systems estuaries and coastal waters receive and food choices (5.2); climate inputs of nutrients (nitrates and
inorganic plant nutrients (nitrates and phosphates), toxic metals, synthetic compounds, suspended solids, hot water, oil, radioactive pollution, pathogens, light, noise and biological pollutants (invasive species). A wide range of parameters can be used to directly test the quality of aquatic systems, including pH, temperature, suspended solids (turbidity), metals, nitrates and phosphates. Biodegradation of organic material utilizes oxygen, which can lead to anoxic conditions and subsequent anaerobic decomposition, which in turn leads to formation of methane, hydrogen sulfide and ammonia (toxic gases). Biochemical oxygen demand (BOD) is a measure of the amount of dissolved oxygen required to break down the organic material in a given volume of water through aerobic biological activity. BOD is used to indirectly measure the amount of organic matter within a sample. Some species can be indicative of polluted waters and can be used as indicator species. A biotic index indirectly measures pollution by assaying the impact on species within the community according to their tolerance, diversity and relative abundance. Eutrophication can occur when lakes, estuaries and coastal waters receive inputs of nutrients (nitrates and Sources of marine pollution should include rivers, pipelines, atmosphere and activities at sea (operational and accidental discharges). The role of positive and negative feedback in the process of eutrophication should be covered. Coastal eutrophication can lead to red tide blooms. With respect to measuring aquatic pollution, a polluted and an unpolluted site (for example, upstream and downstream of a point source) should be compared. International-mindedness: Countries with limited access to clean water often have higher incidences of water-borne illnesses. Theory of knowledge: A wide range of parameters are used to test the quality of water and judgments are made about causes and effects of water quality—how can we effectively identify cause–effect relationships, given that we can only ever observe correlation? Connections: ESS: Terrestrial food production systems and food choices (5.2); climate
IB_Environmental_Systems_and_Societies_2016.docx