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What is Wrong With This Lake?. Eutrophication. Nutrient Cycles Out Of Balance. What is Eutrophication?. An increase in chemical nutrients in an ecosystem Related to chemicals containing nitrogen or phosphorus (e.g. fertilizers and soap) Results in excessive plant growth and decay.
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Eutrophication Nutrient Cycles Out Of Balance
What is Eutrophication? • An increase in chemical nutrients in an ecosystem • Related to chemicals containing nitrogen or phosphorus (e.g. fertilizers and soap) • Results in excessive plant growth and decay
Signs of Eutrophication • Thick algae “skum” on the surface of water • Smell of rotting plants and animals
A Healthy Lake • Low nutrient levels • Normal levels of algae • Lots of oxygen in the water • Results in a variety of fish • Sunlight reaches the bottom • Good plant growth
A “Sick” Lake • High nutrient levels • High levels of algae growth • Sunlight blocked at the surface • Bottom plants die • Plant decay removes oxygen from the water • Lack of oxygen in the water • Fish start to die
Causes of Eutrophication • Can be natural • Leaching (run-off) from rocks and soil • Animal waste • Often because of human activity. • Mining and forestry disturbing the soil • Fertilizer from farms (containing nitrates, phosphates and ammonia) • Sewage from factories and cities (containing soap and other detergents)
How do we fix the problem? • reducing the use of phosphates as builders in detergents • reducing the use of nitrate containing fertilizers • directing waste water away from lakes to rivers and the sea • aerating lakes and reservoirs to prevent oxygen depletion particularly during algal blooms • removing phosphate-rich plant material from affected lakes