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.
Learn more: USGS Water Science School - Why are some lakes full of algae?
Related Content
Why is our porcelain sink stained brown?
Why does my drinking water look cloudy sometimes?
Why does it take so long to rinse the soap off my hands? What are hard water and soft water?
Where can I find information about my local drinking water supply?
What can cause our water to have an earthy odor or to smell like rotten eggs?
What can be causing our drinking water to have a reddish color?
Does the use of pesticides affect our Nation's water quality?
How does mine drainage occur?
Phosphorus and River Water Quality
Investigating the effects of historical phosphorus on current river water quality.
Global Study Finds Algal Blooms Intensifying in Freshwater Lakes Worldwide
A study of global freshwater algal blooms funded in part by a U.S. Geological Survey (USGS) Landsat Science Team (LST) Award has found that harmful blooms showing up more and more in various U.S. cities are intensifying in lakes worldwide as well.
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.
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.