Why are some lakes full of algae and thick plants?
Plants naturally grow in and around lakes, but sometimes lakes and ponds can get an overgrowth of plants, algae, or bacteria. In many cases, humans are responsible. Chemicals that are used on lawns and in agriculture (like nitrogen and potassium) wash into our water systems. Once there, plants and algae have a feast on this “food”.
Sometimes overgrowths of cyanobacteria (called “blooms”) can make the water scummy and turn it a blue-green color (or other colors). Cyanobacteria produce compounds that impact the taste and odor of water, make fish unpalatable, and even produce toxins that affect human health. Scientists are still studying the causes of these blooms.
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Harmful algal blooms
This postcard provides details about "Cyanobacterial Harmful Algal Blooms and U.S. Geological Survey Science Capabilities, "Open File Report 2016-1174, where you can find details about how U.S. Geological Survey (USGS) scientists use traditional methods and emerging technologies in collaboration with numerous partners to lead a diverse range of...
Agriculture — 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,...
Capel, Paul D.; McCarthy, Kathleen A.; Coupe, Richard H.; Grey, Katia M.; Amenumey, Sheila E.; Baker, Nancy T.; Johnson, Richard L.
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,...
Munn, Mark D.; Frey, Jeffrey W.; Tesoriero, Anthony J.; Black, Robert W.; Duff, John H.; Lee, Kathy E.; Maret, Terry R.; Mebane, Christopher A.; Waite, Ian R.; Zelt, Ronald B.
Monitoring indicators of harmful cyanobacteria in Texas
Harmful algal blooms can occur when certain types of microscopic algae grow quickly in water, forming visible patches that might harm the health of the environment, plants, or animals. In freshwater, species of Cyanobacteria (also known as bluegreen algae) are the dominant group of harmful, bloom-forming algae. When Cyanobacteria form a harmful...
Kiesling, Richard L.; Gary, Robin H.; Gary, Marcus O.
Harmful Algal Blooms
What are Harmful Algal Blooms (HABs)? Freshwater and marine harmful algal blooms (HABs) can occur anytime water use is impaired due to excessive accumulations of algae. HAB occurrence is affected by a complex set of physical, chemical, biological, hydrological, and meteorological conditions making it difficult to isolate specific causative...
Graham, Jennifer L.
An annotated key to the identification of commonly occurring and dominant genera of algae observed in the phytoplankton of the United States
In early 1979, a retrieval was made for all phytoplankton data contained in the computerized data file of the U. S. Geological Survey. The retrieval revealed the analytical results of 17,959 samples collected and processed between October 1973 and October 1978. Of the approximately 500 genera of freshwater algae reported in the United States, the...
Greeson, Phillip E.
USGS Kicks Off Innovative Project to Study Harmful Algal Blooms in New York
Monitoring Effort Supports State’s Initiative to Combat Potentially Toxic Blooms
Salty water causes some freshwater harmful algae to release toxins
USGS study of Lake Okeechobee algae gives new insight on South Florida coastal blooms
20 Years Researching Harmful Algal Blooms Supports Sustainable Water Supply in Wichita
Two decades of harmful algal bloom, nutrient and sediment research by the U.S. Geological Survey is helping to support Wichita’s long-term vision of a sustainable water supply into the future. Early warning indicators of harmful algal blooms have been developed for Cheney Reservoir, Kansas, according to a new USGS publication done in cooperation with the City of Wichita, Kansas.
Tracking the Bad Guys: Toxic Algal Blooms
Every few days, a fleet of satellites orbiting 700 kilometers above the Earth scans the continental United States to help keep Americans safe. But these eyes in the sky aren’t seeking terrorists or enemy combatants: they scrutinize lakes to locate problems of the microbial variety, namely cyanobacteria.
The Science of Harmful Algal Blooms
Building knowledge to protect ecological and human health
Nutrient Experiments May Help Gain a Better Understanding of Algal Blooms in Utah
Scientists to test the Great Salt Lake and Utah Lake
New Science Challenges Old Assumptions about Harmful Algal Blooms
First-of-its-kind survey shows that algal toxins are found nationwide.
Algal Toxins Detected in One-Third of Streams Assessed in Southeastern United States
USGS scientists have detected toxins known as microcystins produced by various forms of algae in 39 percent of the small streams assessed throughout the southeastern United States. Their recent study looked at 75 streams in portions of Alabama, Georgia, North Carolina, South Carolina and Virginia.
Key Study Launched to Understand Increased Algae Growth in Lake Tahoe
The U.S. Geological Survey and the University of Nevada, Reno, will study the cause of eutrophication, or increased algae growth, along the nearshore of Lake Tahoe. Supported by California’s Lahontan Water Quality Control Board, the investigation is in response to widespread concerns with water quality and ecological degradation of the lake’s nearshore environment.
Multiple Satellite Eyes to Track Algal Threat to U.S. Freshwater
Four federal agencies including the U.S. Geological Survey have joined forces in an effort to transform satellite data into vital information to protect the American public from freshwater contaminated by harmful algal blooms.
Causes of Toxic Golden Algal Blooms Determined
The causes of toxic golden algal blooms in Texas reservoirs are now better understood, according to a new study by the U.S. Geological Survey.
Cyanobacteria - Scytonema (blue green algae)
Microscopic view of blue green algae sample. Some algae produce toxins that threaten the health and safety of living things that come in direct contact. Cyanobacteria - Scytonema (blue green algae)
Cyanobacteria - Phormidium (blue green algae)
Microscopic view of blue green algae sample. Some algae produce toxins that threaten the health and safety of living things that come in direct contact. Cyanobacteria - Phormidium (blue green algae)
Landsat Image of Cyanobacteria
Images from Landsat, and other satellites, help locate the blue-green swirls associated with cyanobacteria. Photograph credit: NASA.
Aerial View of Lake Okeechobee
An aerial view of Lake Okeechobee in Florida shows an algal bloom. A third of all lakes studied by the USGS contained toxins produced by similar blooms. Photograph credit: Nicholas Aumen, USGS.
Collecting a sample from a cyanobacterial bloom
USGS scientist collecting a sample from a cyanobacterial bloom from Milford Lake, KS; Sept. 2, 2011.
Algal Toxin Photo
Creek filled with Algal Toxins is surrounded by plant life on both banks. Trees line the background.
Cyanobacteria - Nostoc (blue green algae)
Microscopic view of blue green algae sample. Some algae produce toxins that threaten the health and safety of living things that come in direct contact. Cyanobacteria - Nostoc (blue green algae)
Cyanobacteria - Dolichospermum (blue green algae)
Microscopic view of blue green algae sample. Some algae produce toxins that threaten the health and safety of living things that come in direct contact. Cyanobacteria - Dolichospermum (blue green algae)
Harmful Algal Bloom (HAB) in a stream
Algal Bloom on Upper Klamath Lake
A view of an algal bloom in Upper Klamath Lake from field sampling boat.