Ecology
Eutrophication
Excessive nutrient enrichment of water bodies, typically from agricultural runoff or sewage, causing algal blooms that deplete oxygen and kill aquatic life.
Biological Context
Nitrogen and phosphorus from fertilizers fuel algal growth. When algae die, decomposition consumes oxygen, creating 'dead zones' where fish and other organisms cannot survive. Eutrophication has created hundreds of ocean dead zones and degraded freshwater ecosystems worldwide.