5.4 Eutrophication

What was the impact of the eutrophication in Lake erie?

- Decline in biodiversity - Ecosystems species diversity reduced - Oxygen depletion = death of fish - Thickening of lake sediment due to build up of dead organic matter

What are the impacts of eutrophication?

- Increased turbidity - Rate of sediment deposition increases - Net primary productivity higher - DO increases - Diversity of primary producers changes- dominant species changes - Death of aerobic organisms, loss of macrophytes - Algal blooms - Anoxia - Loss of species diversity

How can the water bodies be restored?

- Mud pumping - removal of nutrient enriched sediments - Removal of biomass - Mechanical removal of plants - removing nitrogen

How can human activities be altered?

- Phosphate free detergents in the home - Reduced residential use of lawn fertilisers - Reduced reliance on agricultural fertilisers heavy in phosphorus and nitrogen - Soil consevration

How can eutrophication be regulated and reduced?

- Sewage treatment modifications - Treatment marshes on farms - Domestic campaigns

How was lake erie saved?

- University of manitoba established an experimental lake to try and devise a pollution management strategy to prevent eutrophication - Legislation to control phosphates in sewage and to remove them from detergents etc.

What processes occur in eutrophication

1) Algal blooms- increase nitrogen and phosphorus are carried into streams, lakes and ground water causing nutrient enrichment 2) Anoxia - Increase in algae and plankton shade life below resulting in anoxia 3) Change in species composition- Increased build up in dead matter leads to changes in species composition

What are 3 ways that eutrophication can be dealt with?

1) Altering human activities that produce pollution - replace 2) Regulate and reduce pollutants at the point of emission - reduce 3) Clean up and restoration of polluted water by pumping mud from eutrophic lakes

What are the steps of eutrophication?

1- nutrients wash into river or stream 2- Algae grow quickly in response to increased nutrients 3- Algae block sunlight to aquatic plants= slow photosynthesis, less oxygen in water, low DO levels 4- Decomposer populations increase due to more food(algae) they use up all of the oxygen for respiration = high BOD levels 5- Fish and other consumers die due to lack of oxygen and lack of producers at the base of the pyramid 6- Oxygen levels decline and dead organic matter forms sediments on the lake or river - turbidity increases 7- All life is gone and sediment settles to leave a clear blue lake

What is natural eutrophication?

A process of primary succession

What is anthropogenic eutrophication?

Human activities cause phosphorus(domestic detergents) and nitrogen(air pollution, farm runoff) levels to increase

What is a case study of eutrophication?

Lake Erie in Canada - Rapid anthropogenic eutrophication during 1960s

What is the impact on a freshwater ecosystem?

Loss of submerged aquatic plants - thought to disappear as they lose their energy supply

Define eutrophication

The nutrient enrichment of streams, ponds and groundwater, caused when increased levels of nitrogen or phosphorus are carried into water bodies.

What are the physical impacts?

Ugly Smelly and effects aesthetic value of ecosystem