Point source or non-point source pollution? Eutrophication Definition: The rapid growth of plants which reduce oxygen supply in water, caused by excess nutrients Causes: Nitrates from fertilisers applied to surrounding arable land Phosphates from animal slurry Phosphates from sewage effluent from settlements and holiday centres Point source or non-point source pollution?

Effects of Eutrophication

Ecological Impacts What role do positive feedback mechanisms play in the process of eutrophication? Explain why eutrophication can have the following ecological impacts: death of aerobic organisms (invertebrates, fish, amphibians) increased turbidity (cloudiness) loss of macrophytes (emergent, submergent or floating aquatic plants) shortening of food chains loss of species diversity

Tackling Eutrophication Dredging out algal mud Damming small broads to prevent pollution from main broads and rivers Extracting more phosphates at sewage treatment works Grants to farmers to recreate traditional grazing lands, with limited/no fertiliser application

MANAGEMENT of EUTROPHICATION Pollution management can be considered using three broad strategies: replace (with alternatives) regulate (the release) restore (the environment) Factors such as culture, politics and economics influence strategies used to manage pollution. Case Study: Norfolk Broads, UK

Effects on Norfolk Broads:

Strategies specific to tackling eutrophication