Nutrient pollution

Nutrient pollution, a form of water pollution, refers to contamination by excessive inputs of nutrients. It is a primary cause of eutrophication of surface waters, in which excess nutrients, usually or, stimulate algal growth. Sources of nutrient pollution include surface runoff from farm fields and pastures, discharges from septic tanks and feedlots, and emissions from combustion. Excess nutrients have been summarized as potentially leading to: In a 2011 United States Environmental Protection Agency report, the agency's Science Advisory Board succinctly stated: “Excess reactive nitrogen compounds in the environment are associated with many large-scale environmental concerns, including eutrophication of surface waters, toxic algae blooms, hypoxia, acid rain, nitrogen saturation in forests, and global warming.”
 * Population effects: excess growth of algae (blooms);
 * Community effects: species composition shifts (dominant taxa);
 * Ecological effects:food web changes, light limitation;
 * Biogeochemical effects: excess organic (eutrophication); dissolved oxygen deficits (environmental hypoxia); toxin production;
 * Human health effects: excess nitrate in drinking water (blue baby syndrome); disinfection by-products in drinking water.