The coastline is not as clear in Clear Lake, California.
A satellite image taken by NASA shows the popular tourist destination so overgrown with bright green algae that it is visible from space.
The light swirls visible in the May 15 photo covered most of the freshwater lake, located about 120 miles north of San Francisco and is the Golden State’s largest natural freshwater lake and oldest lake from North America.
The bloom could pose a threat to marine animals and humans, according to the agency, and officials warn it could affect recreational activities.
The bloom may contain blue-green algae, also known as cyanobacteria, which can produce a powerful toxin that can cause skin rashes, eye irritation and respiratory problems.
In extreme and rare cases, it can lead to gastroenteritis, liver and kidney failure, and even death, according to the Environmental Protection Agency.
Humans are generally exposed through accidental ingestion or inhalation during activities near or on water.
Clear Lake State Park attracts visitors for swimming, fishing, boating and water skiing.
Only a direct sample will allow the exact composition of the lake bloom to be determined.
Toxicity monitoring conducted on May 8 did not show blooms and the next sampling will take place on June 4, the Los Angeles Times reported.
Cyanobacteria are a type of phytoplankton, a floating plant-like organism that reproduces abundantly with the right nutrients, sunlight, and water conditions.
Clear Lake is already a nutrient-rich body of water, and humans have recently contributed to an increase in harmful vegetation, studies show.
The lake, which is one of the Golden State’s most visited lakes, once lived up to its name but has become murkier due to the entry of nutrients such as phosphorus through tributaries, according to the U.S. Geological Survey .
Officials say runoff from nearby farms, vineyards, faulty septic tanks, gravel mines and an abandoned open-pit mercury mine are likely the cause.
Waves and non-native carp also throw nutrients from the lake bed into the water.
The flowers generally appear every year and thrive during the summer months.
New York Post
