Nutrient sources in both agricultural and urban areas contribute to elevated nutrient concentrations in streams and groundwater across the nation.
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
Water-Quality Benchmarks for Contaminants
SPARROW modeling: Estimating nutrient, sediment, and dissolved solids transport
NWQP Research on Harmful Algal Blooms (HABs)
Groundwater/Surface-Water Interaction
Agricultural Contaminants
Regional Stream Quality Assessment (RSQA)
Phosphorus and Water
Nitrogen and Water
Biological Response to Nutrients
Excess Nutrients
Below are data or web applications related to USGS research on nutrients.
Data and model archive for multiple linear regression models for prediction of weighted cyanotoxin mixture concentrations and microcystin concentrations at three recurring bloom sites in Kabetogama Lake in Minnesota
Input and results from a boosted regression tree (BRT) model relating base flow nitrate concentrations in the Chesapeake Bay watershed to catchment characteristics (1970-2013)
Datasets and metadata for estimates of nitrate loads and yields from groundwater to streams in the Chesapeake Bay watershed based on land use and geology
County-Level Estimates of Nitrogen and Phosphorus from Commercial Fertilizer for the Conterminous United States, 1987-2012
Water Quality and Hydrologic Data (2011-13) for Freshwater Science Paper titled, "Patterns of Diel Variation in Nitrate Concentrations in the Potomac River"
Below are a few videos and images related to nutrients and eutrophication.
Nutrient sources in both agricultural and urban areas contribute to elevated nutrient concentrations in streams and groundwater across the nation.
Increasing nitrogen emissions from motor vehicles, energy production, and agriculture are being deposited in lakes throughout the world, directly affecting lake biology and associated food webs. Alpine lake ecosystems are especially vulnerable to this deposition.
Increasing nitrogen emissions from motor vehicles, energy production, and agriculture are being deposited in lakes throughout the world, directly affecting lake biology and associated food webs. Alpine lake ecosystems are especially vulnerable to this deposition.
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
Nitrogen and phosphorus sources and delivery from the Mississippi/Atchafalaya River Basin: An update using 2012 SPARROW models
Factors affecting nitrate concentrations in stream base flow
Nitrate in streams during winter low‐flow conditions as an indicator of legacy nitrate
Cyanotoxin occurrence in large rivers of the United States
Cyanotoxins occur in rivers worldwide but are understudied in lotic ecosystems relative to lakes and reservoirs. Eleven large river sites located throughout the United States were sampled during June–September 2017 to determine the occurrence of cyanobacteria with known cyanotoxin-producing strains, cyanotoxin synthetase genes, and cyanotoxins. Chlorophyll-a concentrations spanned the range from o
Network controls on mean and variance of nitrate loads from the Mississippi River to the Gulf of Mexico
Using age tracers and decadal sampling to discern trends in nitrate, arsenic and uranium in groundwater beneath irrigated cropland
Response of nitrogen loading to the Chesapeake Bay to source reduction and land use change scenarios: A SPARROW‐informed analysis
Variable impacts of contemporary versus legacy agricultural phosphorus on US river water quality
Phosphorus and nitrogen transport in the binational Great Lakes Basin estimated using SPARROW watershed models
Drinking water quality in the glacial aquifer system, northern USA
Monitoring the Riverine Pulse: Applying high-frequency nitrate data to advance integrative understanding of biogeochemical and hydrological processes
Point-source nutrient loads to streams of the conterminous United States, 2012
There are numerous software packages scientists use to investigate water quality and pollution transport. Here are a few examples of applications USGS uses.
RSPARROW
RSPARROW, now available on the USGS GitLab repository, provides the first open-source version of the USGS SPARROW water-quality model
SPARROW modeling: Estimating contaminant transport
SPARROW (SPAtially Referenced Regression On Watershed attributes) models estimate the amount of a contaminant transported from inland watersheds to larger water bodies by linking monitoring data with information on watershed characteristics and contaminant sources.
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.
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
Water-Quality Benchmarks for Contaminants
SPARROW modeling: Estimating nutrient, sediment, and dissolved solids transport
NWQP Research on Harmful Algal Blooms (HABs)
Groundwater/Surface-Water Interaction
Agricultural Contaminants
Regional Stream Quality Assessment (RSQA)
Phosphorus and Water
Nitrogen and Water
Biological Response to Nutrients
Excess Nutrients
Below are data or web applications related to USGS research on nutrients.
Data and model archive for multiple linear regression models for prediction of weighted cyanotoxin mixture concentrations and microcystin concentrations at three recurring bloom sites in Kabetogama Lake in Minnesota
Input and results from a boosted regression tree (BRT) model relating base flow nitrate concentrations in the Chesapeake Bay watershed to catchment characteristics (1970-2013)
Datasets and metadata for estimates of nitrate loads and yields from groundwater to streams in the Chesapeake Bay watershed based on land use and geology
County-Level Estimates of Nitrogen and Phosphorus from Commercial Fertilizer for the Conterminous United States, 1987-2012
Water Quality and Hydrologic Data (2011-13) for Freshwater Science Paper titled, "Patterns of Diel Variation in Nitrate Concentrations in the Potomac River"
Below are a few videos and images related to nutrients and eutrophication.
Nutrient sources in both agricultural and urban areas contribute to elevated nutrient concentrations in streams and groundwater across the nation.
Nutrient sources in both agricultural and urban areas contribute to elevated nutrient concentrations in streams and groundwater across the nation.
Increasing nitrogen emissions from motor vehicles, energy production, and agriculture are being deposited in lakes throughout the world, directly affecting lake biology and associated food webs. Alpine lake ecosystems are especially vulnerable to this deposition.
Increasing nitrogen emissions from motor vehicles, energy production, and agriculture are being deposited in lakes throughout the world, directly affecting lake biology and associated food webs. Alpine lake ecosystems are especially vulnerable to this deposition.
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
Nitrogen and phosphorus sources and delivery from the Mississippi/Atchafalaya River Basin: An update using 2012 SPARROW models
Factors affecting nitrate concentrations in stream base flow
Nitrate in streams during winter low‐flow conditions as an indicator of legacy nitrate
Cyanotoxin occurrence in large rivers of the United States
Cyanotoxins occur in rivers worldwide but are understudied in lotic ecosystems relative to lakes and reservoirs. Eleven large river sites located throughout the United States were sampled during June–September 2017 to determine the occurrence of cyanobacteria with known cyanotoxin-producing strains, cyanotoxin synthetase genes, and cyanotoxins. Chlorophyll-a concentrations spanned the range from o
Network controls on mean and variance of nitrate loads from the Mississippi River to the Gulf of Mexico
Using age tracers and decadal sampling to discern trends in nitrate, arsenic and uranium in groundwater beneath irrigated cropland
Response of nitrogen loading to the Chesapeake Bay to source reduction and land use change scenarios: A SPARROW‐informed analysis
Variable impacts of contemporary versus legacy agricultural phosphorus on US river water quality
Phosphorus and nitrogen transport in the binational Great Lakes Basin estimated using SPARROW watershed models
Drinking water quality in the glacial aquifer system, northern USA
Monitoring the Riverine Pulse: Applying high-frequency nitrate data to advance integrative understanding of biogeochemical and hydrological processes
Point-source nutrient loads to streams of the conterminous United States, 2012
There are numerous software packages scientists use to investigate water quality and pollution transport. Here are a few examples of applications USGS uses.
RSPARROW
RSPARROW, now available on the USGS GitLab repository, provides the first open-source version of the USGS SPARROW water-quality model
SPARROW modeling: Estimating contaminant transport
SPARROW (SPAtially Referenced Regression On Watershed attributes) models estimate the amount of a contaminant transported from inland watersheds to larger water bodies by linking monitoring data with information on watershed characteristics and contaminant sources.
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.