Definition

A process where excess nutrients (typically nitrates and phosphates) build up in rivers, lakes, and coastal waters. This nutrient excess means aquatic plants like algae grow excessively and deplete the water’s oxygen. Overgrowth of algae (algal blooms) near the surface can also stop sunlight reaching other aquatic plants, which then die and decompose, which uses up more oxygen. Oxygen levels drop and drop until ‘dead zones’ are created where no aquatic life can survive. Sewage and farming waste runoffs (fertiliser and animal manure) are important causes of eutrophication.

Further reading
What is eutrophication? - National Oceanic and Atmospheric Administration (NOAA)[website]
About Eutrophication - World Resources Institute (WRI) [website]
Eutrophication science: where do we go from here? (Smith & Schindler, 2009) [journal article]
Related

agricultural nutrient runoff; agricultural surface runoff; agricultural wastewater treatment; algae bloom; algae growth; algae overgrowth; animal waste; anoxia/anoxic; anthropogenic eutrophication; aquatic ecosystems; chemical fertilisers; cultural eutrophication; effluents; excess nitrates; excess nitrogen; excess phosphates; excess phosphorus; fertiliser runoff; fish kills; Harmful Algal Blooms (HABs); hypoxia/hypoxic; low-oxygen zones; nitrate fertilisers; nutrient enrichment; nutrient loading; nutrient management; nutrient overloading; nutrient pollution; nutrient runoff; oxygen-depleted waters; oxygen depletion; sewage pollution; surface runoff; water pollution

See also
Agriculture
Anthropogenic
Pollution
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Environmental Changes
Food & Farming
Drafted by
Chris Graham
Reviewed by
TBC