5.4: Eutrophication

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  • Eutrophication is the addition of excess nutrients to a water system, which leads to the growth and subsequent death of algae, which reduces the dissolved oxygen available for other aquatic organisms
  • Or simply: the process of nutrient enrichment of an ecosystem

Process(Positive Feedback):
  1. Increase in inputs of nutrients (nitrates and phosphates) which enter the lake
  2. Increase in algae productivity in the lake
  3. Massive increase in algae
  4. Increase in dead organic matter due to increase in decomposer as there are more algae for food
  5. Higher rate of decomposition as the decomposers respiration
  6. Increase in oxygen demand but decline in oxygen level
  7. Death of organisms

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5.4.2 Evaluate the impacts of Eutrophication.

Impact
  • Death of aerobic animals
  • Organisms been poisoned due to algal blooms
  • Increase of turbidity
  • Loss of macrophysics
  • Declines in biodiversity and loss in food chain length
  • Loss of water resources to human
  • Impact on tourism due to bad smell and aesthetic reasons


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5.4.3 Describe and evaluate pollution management strategies with respect to Eutrophication.

Minimize the amount of nutrients being released into the system by:
  • limiting production/use of detergents containing phosphates
  • create buffer zones between agricultural land and water sources
  • prevent animal waste from leaching into groundwater and rivers/streams

Treat the polluted area by:
  • pumping air into the water source
  • divert or treat sewage properly
  • dredge (dig up) contaminated sediments
  • physically remove algae blooms