Nutrients, eutrophication and harmful algal blooms along the freshwater to marine continuum

• Published in: Wiley interdisciplinary reviews. Water Vol. 6; no. 5; pp. e1373 - n/a
• Main Authors: Wurtsbaugh, Wayne A., Paerl, Hans W., Dodds, Walter K.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.09.2019; Wiley Subscription Services, Inc
• Subjects: Agricultural management; Algae; Algal blooms; aquatic; Aquatic ecosystems; coastal; Coastal waters; Coastal zone; Control; dead zones; Drinking water; ecology; Ecosystems; Estuaries; Estuarine environments; Eutrophication; Fish; Food supply; Freshwater; Greenhouse effect; Greenhouse gases; harmful algal bloom; Headwaters; Hypoxia; Industrial areas; Inland water environment; Lakes; Marine ecosystems; Mineral nutrients; Nitrogen; Nutrients; Oceans; Odor; Odors; Odour; Phosphorus; Rivers; Sensory stimulation; Shellfish; Social values; Streams; Unidirectional flow; Urban agriculture; Water pollution; Water quality
• ISSN: 2049-1948; 2049-1948
• DOI: 10.1002/wat2.1373

Agricultural, urban and industrial activities have dramatically increased aquatic nitrogen and phosphorus pollution (eutrophication), threatening water quality and biotic integrity from headwater streams to coastal areas world‐wide. Eutrophication creates multiple problems, including hypoxic “dead zones” that reduce fish and shellfish production; harmful algal blooms that create taste and odor problems and threaten the safety of drinking water and aquatic food supplies; stimulation of greenhouse gas releases; and degradation of cultural and social values of these waters. Conservative estimates of annual costs of eutrophication have indicated $1 billion losses for European coastal waters and $2.4 billion for lakes and streams in the United States. Scientists have debated whether phosphorus, nitrogen, or both need to be reduced to control eutrophication along the freshwater to marine continuum, but many management agencies worldwide are increasingly opting for dual control. The unidirectional flow of water and nutrients through streams, rivers, lakes, estuaries and ultimately coastal oceans adds additional complexity, as each of these ecosystems may be limited by different factors. Consequently, the reduction of just one nutrient upstream to control eutrophication can allow the export of other nutrients downstream where they may stimulate algal production. The technology exists for controlling eutrophication, but many challenges remain for understanding and managing this global environmental problem. This article is categorized under: Science of Water > Water Quality Water and Life > Stresses and Pressures on Ecosystems Considerable gains have been made in controlling eutrophication in rivers, lakes and coastal areas, but much work remains to be done. Location—Great Salt Lake, Utah. Photograph by W. Wurtsbaugh.