Eutrophication

Eutrophication is what a water-based ecosystem does when too many nutrients are added to it. Eutrophication is mainly caused by two nutrients, phosphorus and nitrogen. These are brought to aquatic ecosystems as runoff from fertilized agricultural areas, erosion from river banks, river beds, clearing of land (deforestation), or sewage that ends up in aquatic environments. This causes algal blooms, the accumulation of algaer. When the algae die, they deplete the dissolved oxygen in the water.

Eutrophication Media

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  Eutrophication can cause harmful algal blooms like this one in a river near Chengdu, China.

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  Skeletal model of sodium tripolyphosphate

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  An example in Tennessee of how soil from fertilized fields can turn into runoff after a storm, creating a flux of nutrients that flow into local bodies of water such as lakes and creeks

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  The eutrophication of Mono Lake, which is a cyanobacteria-rich soda lake

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  Eutrophication is apparent as increased turbidity in the northern part of the Caspian Sea, imaged from orbit.

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  An algal bloom in Lake Valencia, the largest freshwater lake in Venezuela. Since 1976 the lake has been affected by eutrophication caused by wastewater.

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  Autumn in Netherlands

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  Bivalves at Strawberry Rocks, Oudekraal.

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  Application of a phosphorus sorbent to a lake - The Netherlands