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 normally 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. The major consequence of eutrophication are algal blooms.
Eutrophication Media
Eutrophication can cause harmful algal blooms like this one in a river near Chengdu, China.
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
The eutrophication of Mono Lake, which is a cyanobacteria-rich soda lake
Eutrophication is apparent as increased turbidity in the northern part of the Caspian Sea, imaged from orbit.