Nutrients and Eutrophication Active
Agriculture, Nutrients, and the Nation's Waters
Affecting every component of the hydrologic system
Like people, plants need nutrients, but too much of a good thing can be a problem. Nutrients, such as nitrogen and phosphorus, occur naturally, but most of the nutrients in our waterways come from human activities and sources—fertilizers, wastewater, automobile exhaust, animal waste. The USGS investigates the source, transport, and fate of nutrients and their impacts on the world around us.
Featured: Nutrient yields in the Mississippi/Atchafalaya River Basin
A new USGS study estimates total nitrogen (N) and total phosphorus (P) yields from catchments throughout the Mississippi/Atchafalaya River Basin, which drains about 41% of the conterminous U.S. Results could assist nutrient reduction strategies.
BACKGROUND
Nutrients are essential for plant growth, but the overabundance of nutrients in water can have many harmful health and environmental effects. An overabundance of nutrients—primarily nitrogen and phosphorus—in water starts a process called eutrophication. Algae feed on the nutrients, growing, spreading, and turning the water green. Algae blooms can smell bad, block sunlight, and even release toxins in some cases. When the algae die, they are decomposed by bacteria—this process consumes the oxygen dissolved in the water and needed by fish and other aquatic life to "breathe". If enough oxygen is removed, the water can become hypoxic, where there is not enough oxygen to sustain life, creating a "dead zone".
WHAT ARE NUTRIENTS?
Nutrients are chemical elements found in the food that plants and animals need to grow and survive. Although there are many kinds of nutrients, two of the most important and abundant are nitrogen and phosphorus. Nitrogen and phosphorus occur in a variety of forms, or species, and the species present can change as they move between the air, water, and soil.
- AMMONIA (NH3) and AMMONIUM (NH4+) are among the primary forms of nitrogen in natural waters. Ammonia can be toxic to fish. It is also soluble in water and relatively unstable in most environments. Ammonia is easily transformed into nitrate (NO3-) in waters that contain sufficient dissolved oxygen or into nitrogen gas in waters that have no dissolved oxygen.
- NITRATE (NO3-) is another primary form of nitrogen in lakes and streams. Nitrate is verysoluble in water and is stable over a wide range of environmental conditions. It is readily transported in groundwater and streams. An excessive amount of nitrate in drinking water can cause health problems.
- PHOSPHATES (containing PO43−) are the most common form of phosphorus in natural waters. Phosphates are only moderately soluble and, compared to nitrate, are not very mobile in soils and groundwater. Phosphates tend to remain attached to soil particles, but erosion can transport considerable amounts of phosphate to streams and lakes.
Learn more about nutrients in our Nation's surface water and groundwater.
USGS Circular 1350
WHAT HAPPENS WHEN THERE ARE EXCESSIVE NUTRIENTS?
Eutrophication is a natural process that results from accumulation of nutrients in lakes or other bodies of water. Algae that feed on nutrients grow into unsightly scum on the water surface, decreasing recreational value and clogging water-intake pipes. Decaying mats of dead algae can produce foul tastes and odors in the water; their decay by bacteria consumes dissolved oxygen from the water, sometimes causing fish kills. Human activities can accelerate eutrophication by increasing the rate at which nutrients enter the water. Algal growth is usually limited by the available supply of either phosphate or nitrate, and we say that a water body is nitrogen limited if the ratio of nitrogen species to phosphorus species (N:P) is low, or is phosphorus limited if N:P is high.
Harmful algal blooms (HABs) are can be caused by many different types of algae in freshwater ecosystems, and can be triggered by nutrient enrichment. The most frequent and severe blooms typically are caused by cyanobacteria, the only known freshwater algae with the potential for production of toxins potent enough to harm human health. CyanoHABs can threaten human and aquatic ecosystem health. Economic damages related to cyanoHABs include the loss of recreational revenue, decreased property values, and increased drinking-water treatment costs.
RELATED USGS RESEARCH
The USGS works extensively across the country on a variety of aspects related to nutrients and eutrophication. Explore the related projects tab for some examples or click the links below.
- Agriculture and the Quality of the Nation's Waters
- Regional Stream Quality Assessments
- SPARROW modeling: Estimating nutrient, sediment, and dissolved solids transport
- Harmful Algal Blooms
- Effects of Nutrient Enrichment on Stream Ecosystems
- Nutrient Loading for the Mississippi River and Subbasins
- Water-Quality Benchmarks, Including Nutrient Criteria
ADDITIONAL RESOURCES
U.S. Environmental Protection Agency
Natural Resources Conservation Service
Nutrients can come from many areas, but mostly they are associated with runoff from agricultural applications. Here are a few studies that relate to nutrients.
Agriculture and the Quality of the Nation's Waters
Below are data or web applications related to USGS research on nutrients.
Below are a few videos and images related to nutrients and eutrophication.
Follow the links below to USGS publications on nutrients and the quality of our nation's waters.
Understanding the influence of nutrients on stream ecosystems in agricultural landscapes
Point-source nutrient loads to streams of the conterminous United States, 2012
Recent trends in nutrient and sediment loading to coastal areas of the conterminous U.S.: Insights and global context
Catchment-level estimates of nitrogen and phosphorus agricultural use from commercial fertilizer sales for the conterminous United States, 2012
Effects of urban multi-stressors on three stream biotic assemblages
Linking the agricultural landscape of the Midwest to stream health with structural equation modeling
Water-quality trends in US rivers: Exploring effects from streamflow trends and changes in watershed management
Nutrient enrichment in wadeable urban streams in the piedmont ecoregion of the southeastern United States
Agriculture — A river runs through it — The connections between agriculture and water quality
Assessing the influence of multiple stressors on stream diatom metrics in the upper Midwest, USA
County-level estimates of nitrogen and phosphorus from animal manure for the conterminous United States, 2007 and 2012
Statistically extracted fundamental watershed variables for estimating the loads of total nitrogen in small streams
High nitrate concentrations in some Midwest United States streams in 2013 after the 2012 drought
Below are data or web applications related to USGS research on nutrients.
There are numerous software packages scientists use to investigate water quality and pollution transport. Here are a few examples of applications USGS uses.
See what is newsworthy concerning water-quality in the Nation's lakes and rivers.
What's In Your Stream? Get Online to Find Out!
A new update to an online interactive tool for learning about pesticides, nutrients, and overall stream health in major regions of the U.S. is available from the U.S. Geological Survey’s Regional Stream Quality Assessment.
- Overview
Like people, plants need nutrients, but too much of a good thing can be a problem. Nutrients, such as nitrogen and phosphorus, occur naturally, but most of the nutrients in our waterways come from human activities and sources—fertilizers, wastewater, automobile exhaust, animal waste. The USGS investigates the source, transport, and fate of nutrients and their impacts on the world around us.
Featured: Nutrient yields in the Mississippi/Atchafalaya River BasinA new USGS study estimates total nitrogen (N) and total phosphorus (P) yields from catchments throughout the Mississippi/Atchafalaya River Basin, which drains about 41% of the conterminous U.S. Results could assist nutrient reduction strategies.
BACKGROUND
Nutrients are essential for plant growth, but the overabundance of nutrients in water can have many harmful health and environmental effects. An overabundance of nutrients—primarily nitrogen and phosphorus—in water starts a process called eutrophication. Algae feed on the nutrients, growing, spreading, and turning the water green. Algae blooms can smell bad, block sunlight, and even release toxins in some cases. When the algae die, they are decomposed by bacteria—this process consumes the oxygen dissolved in the water and needed by fish and other aquatic life to "breathe". If enough oxygen is removed, the water can become hypoxic, where there is not enough oxygen to sustain life, creating a "dead zone".
WHAT ARE NUTRIENTS?
Nutrients are chemical elements found in the food that plants and animals need to grow and survive. Although there are many kinds of nutrients, two of the most important and abundant are nitrogen and phosphorus. Nitrogen and phosphorus occur in a variety of forms, or species, and the species present can change as they move between the air, water, and soil.
- AMMONIA (NH3) and AMMONIUM (NH4+) are among the primary forms of nitrogen in natural waters. Ammonia can be toxic to fish. It is also soluble in water and relatively unstable in most environments. Ammonia is easily transformed into nitrate (NO3-) in waters that contain sufficient dissolved oxygen or into nitrogen gas in waters that have no dissolved oxygen.
- NITRATE (NO3-) is another primary form of nitrogen in lakes and streams. Nitrate is verysoluble in water and is stable over a wide range of environmental conditions. It is readily transported in groundwater and streams. An excessive amount of nitrate in drinking water can cause health problems.
- PHOSPHATES (containing PO43−) are the most common form of phosphorus in natural waters. Phosphates are only moderately soluble and, compared to nitrate, are not very mobile in soils and groundwater. Phosphates tend to remain attached to soil particles, but erosion can transport considerable amounts of phosphate to streams and lakes.
Learn more about nutrients in our Nation's surface water and groundwater.
USGS Circular 1350WHAT HAPPENS WHEN THERE ARE EXCESSIVE NUTRIENTS?
Eutrophication is a natural process that results from accumulation of nutrients in lakes or other bodies of water. Algae that feed on nutrients grow into unsightly scum on the water surface, decreasing recreational value and clogging water-intake pipes. Decaying mats of dead algae can produce foul tastes and odors in the water; their decay by bacteria consumes dissolved oxygen from the water, sometimes causing fish kills. Human activities can accelerate eutrophication by increasing the rate at which nutrients enter the water. Algal growth is usually limited by the available supply of either phosphate or nitrate, and we say that a water body is nitrogen limited if the ratio of nitrogen species to phosphorus species (N:P) is low, or is phosphorus limited if N:P is high.
Harmful algal blooms (HABs) are can be caused by many different types of algae in freshwater ecosystems, and can be triggered by nutrient enrichment. The most frequent and severe blooms typically are caused by cyanobacteria, the only known freshwater algae with the potential for production of toxins potent enough to harm human health. CyanoHABs can threaten human and aquatic ecosystem health. Economic damages related to cyanoHABs include the loss of recreational revenue, decreased property values, and increased drinking-water treatment costs.
RELATED USGS RESEARCH
The USGS works extensively across the country on a variety of aspects related to nutrients and eutrophication. Explore the related projects tab for some examples or click the links below.
- Agriculture and the Quality of the Nation's Waters
- Regional Stream Quality Assessments
- SPARROW modeling: Estimating nutrient, sediment, and dissolved solids transport
- Harmful Algal Blooms
- Effects of Nutrient Enrichment on Stream Ecosystems
- Nutrient Loading for the Mississippi River and Subbasins
- Water-Quality Benchmarks, Including Nutrient Criteria
ADDITIONAL RESOURCES
U.S. Environmental Protection Agency
Natural Resources Conservation Service
- Science
Nutrients can come from many areas, but mostly they are associated with runoff from agricultural applications. Here are a few studies that relate to nutrients.
Agriculture and the Quality of the Nation's Waters
Intensive studies by the USGS National Water-Quality Assessment (NAWQA) Project in agricultural areas provide insight into how agricultural activities have altered the natural flow of water and the way that agricultural chemicals enter streams and aquifers, and in particular how nutrients affect algal and invertebrate communities in agricultural streams. - Data
Below are data or web applications related to USGS research on nutrients.
- Multimedia
Below are a few videos and images related to nutrients and eutrophication.
- Publications
Follow the links below to USGS publications on nutrients and the quality of our nation's waters.
Understanding the influence of nutrients on stream ecosystems in agricultural landscapes
Sustaining the quality of the Nation’s water resources and the health of our diverse ecosystems depends on the availability of sound water-resources data and information to develop effective, science-based policies. Effective management of water resources also brings more certainty and efficiency to important economic sectors. Taken together, these actions lead to immediate and long-term economic,AuthorsMark D. Munn, Jeffrey W. Frey, Anthony J. Tesoriero, Robert W. Black, John H. Duff, Kathy Lee, Terry R. Maret, Christopher A. Mebane, Ian R. Waite, Ronald B. ZeltFilter Total Items: 54Point-source nutrient loads to streams of the conterminous United States, 2012
Total nitrogen and phosphorous loads were estimated for 5,430 major point-source facilities (all types) and 11,537 minor wastewater treatment facilities discharging to streams in the conterminous United States during 2012. Facilities classified as a major discharger are typically a facility that discharges greater than one million gallons of water per day however some industrial facilities are claAuthorsKenneth D. Skinner, Molly A. MaupinRecent trends in nutrient and sediment loading to coastal areas of the conterminous U.S.: Insights and global context
Coastal areas in the U.S. and worldwide have experienced massive population and land use changes contributing to significant degradation of coastal ecosystems. Excess nutrient pollution causes coastal ecosystem degradation, and both regulatory and management efforts have targeted reducing nutrient and sediment loading to coastal rivers. Decadal trends in flow-normalized nutrient and sediment loadsAuthorsGretchen P. Oelsner, Edward G. StetsCatchment-level estimates of nitrogen and phosphorus agricultural use from commercial fertilizer sales for the conterminous United States, 2012
Nutrient inputs from commercial agricultural fertilizer, particularly nitrogen and phosphorus, are important factors contributing to the degradation of surface-water quality and the alteration of aquatic ecosystems. Despite this importance, information about the application of fertilizer to agricultural land is not available in a consistent manner across the United States at a scale useful for regAuthorsJana S. Stewart, Gregory E. Schwarz, John W. Brakebill, Stephen D. PrestonEffects of urban multi-stressors on three stream biotic assemblages
During 2014, the U.S. Geological Survey (USGS) National Water-Quality Assessment(NAWQA) project assessed stream quality in 75 streams across an urban disturbance gradient within the Piedmont ecoregion of southeastern United States. Our objectives were to identify primary instream stressors affecting algal, macroinvertebrate and fish assemblages in wadeable streams. Biotic communities were surveyedAuthorsIan R. Waite, Mark D. Munn, Patrick W. Moran, Christopher P. Konrad, Lisa H. Nowell, Michael R. Meador, Peter C. Van Metre, Daren CarlisleLinking the agricultural landscape of the Midwest to stream health with structural equation modeling
Multiple physical and chemical stressors can simultaneously affect the biological condition of streams. To better understand the complex interactions of land-use practices, water quality, and ecological integrity of streams, the U.S. Geological Survey National Water Quality Assessment Project is conducting regional-scale assessments of stream condition across the United States. In the summer of 20AuthorsTravis S. Schmidt, Peter C. Van Metre, Daren CarlisleWater-quality trends in US rivers: Exploring effects from streamflow trends and changes in watershed management
We present a conceptual model that explores the relationship of streamflow trends to 15 water-quality parameters at 370 sites across the contiguous United States (US). Our analytical framework uses discrete water-quality data, daily streamflow records, and a statistical model to estimate water-quality trends between 1982 and 2012 and parse these trends into the amount of change attributed to trendAuthorsJennifer C. Murphy, Lori A. SpragueNutrient enrichment in wadeable urban streams in the piedmont ecoregion of the southeastern United States
The U.S. Geological Survey (USGS) Southeastern Stream Quality Assessment (SESQA) collected weekly samples for nitrogen and phosphorus in 76 wadeable streams in the urbanized Piedmont ecoregion of the Southeastern United States, during April–June 2014. Total nitrogen (TN) concentrations in excess of EPA guidelines and statistically greater than at reference locations indicated nitrogen-nutrient enrAuthorsCeleste A. Journey, Peter C. Van Metre, Daniel T. Button, Jimmy M. Clark, Mark D. Munn, Naomi Nakagaki, Sharon L. Qi, Ian R. Waite, Paul M. BradleyAgriculture — A river runs through it — The connections between agriculture and water quality
Sustaining the quality of the Nation’s water resources and the health of our diverse ecosystems depends on the availability of sound water-resources data and information to develop effective, science-based policies. Effective management of water resources also brings more certainty and efficiency to important economic sectors. Taken together, these actions lead to immediate and longterm economic,AuthorsPaul D. Capel, Kathleen A. McCarthy, Richard H. Coupe, Katia M. Grey, Sheila E. Amenumey, Nancy T. Baker, Richard L. JohnsonAssessing the influence of multiple stressors on stream diatom metrics in the upper Midwest, USA
Water resource managers face increasing challenges in identifying what physical and chemical stressors are responsible for the alteration of biological conditions in streams. The objective of this study was to assess the comparative influence of multiple stressors on benthic diatoms at 98 sites that spanned a range of stressors in an agriculturally dominated region in the upper Midwest, USA. The pAuthorsMark D. Munn, Ian R. Waite, Christopher P. KonradCounty-level estimates of nitrogen and phosphorus from animal manure for the conterminous United States, 2007 and 2012
County-level estimates of nitrogen and phosphorus inputs from animal manure for the conterminous United States were calculated from animal population inventories in the 2007 and 2012 Census of Agriculture, using previously published methods. These estimates of non-point nitrogen and phosphorus inputs from animal manure were compiled in support of the U.S. Geological Survey’s National Water-QualityAuthorsJoAnn M. Gronberg, Terri ArnoldStatistically extracted fundamental watershed variables for estimating the loads of total nitrogen in small streams
Accurate estimation of total nitrogen loads is essential for evaluating conditions in the aquatic environment. Extrapolation of estimates beyond measured streams will greatly expand our understanding of total nitrogen loading to streams. Recursive partitioning and random forest regression were used to assess 85 geospatial, environmental, and watershed variables across 636 small (<585 km2) watersheAuthorsScott C. Kronholm, Paul D. Capel, Silvia TerziottiHigh nitrate concentrations in some Midwest United States streams in 2013 after the 2012 drought
Nitrogen sources in the Mississippi River basin have been linked to degradation of stream ecology and to Gulf of Mexico hypoxia. In 2013, the USGS and the USEPA characterized water quality stressors and ecological conditions in 100 wadeable streams across the midwestern United States. Wet conditions in 2013 followed a severe drought in 2012, a weather pattern associated with elevated nitrogen concAuthorsPeter C. Van Metre, Jeffrey W. Frey, MaryLynn Musgrove, Naomi Nakagaki, Sharon L. Qi, Barbara Mahler, Michael E. Wieczorek, Daniel T. Button - Web Tools
Below are data or web applications related to USGS research on nutrients.
- Software
There are numerous software packages scientists use to investigate water quality and pollution transport. Here are a few examples of applications USGS uses.
- News
See what is newsworthy concerning water-quality in the Nation's lakes and rivers.
What's In Your Stream? Get Online to Find Out!
A new update to an online interactive tool for learning about pesticides, nutrients, and overall stream health in major regions of the U.S. is available from the U.S. Geological Survey’s Regional Stream Quality Assessment.