North America’s oldest lake turned green this month, raising health concerns among officials.
California authorities issued a health warning Friday after the 500,000-year-old Clear Lake became contaminated with harmful blue-green algae.
The algae can release toxins such as microcystin, which irritate the skin and can cause kidney and liver damage if ingested.
And while the bloom occurs naturally, it has become worst in recent years due to mining and sewage disposal.
NASA’s Landsat 9 satellite has captured an image showing North America’s oldest lake turning green (pictured)
Located about 60 miles north of San Francisco Bay, Clear Lake attracts a wide variety of fish and birds, making it a popular location for nature lovers, but its shallow and tepid waters also make it an ideal breeding ground for algae blooms.
Algae play an important role in keeping lakes fertile and healthy by preventing the sun’s rays from reaching the lake bottom, which in turn reduces aquatic weeds that would block oxygen, effectively smothering the lake.
NASA, which captured the bloom from space, reported that the poor water quality stems directly from “runoff from nearby farms, vineyards, failed septic systems, gravel mines and an abandoned open mercury mine.”
If there are enough pollutants in the water, blue-green algae can release microcystin as it dies, making it easy for swimmers to ingest the toxin.
When the microcystin breaks open in the stomach, it can cause serious health problems – from rashes and diarrhea to vomiting, breathing problems, liver damage and neurological effects.
The toxin can also lead to neurological problems when it crosses the blood-brain barrier and enters the brain.
Lake Clear (pictured) has more than 130 species of algae, three of which can contain harmful toxins such as mycocystin. This toxin can cause liver and kidney failure or breathing problems
Historical records show that the lake was relatively clear until 1925, but an increase in ‘erosion, fertilizer and wastewater discharges due to urban and agricultural development were the likely causes of the increased growth of blue-green algae’
As of May 25, microcystin measurements were unavailable, NASA reported, but even if the toxins are not present in the algae, the abundance could still devastate aquatic life.
“Bacteria consume oxygen as they break down dead phytoplankton, which can cause hypoxia and dead zones,” NASA said.
Historical records show that the lake was relatively clear through 1925, but an increase in “erosion, fertilizer, and sewage discharges due to urban and agricultural development” from that year through 1939 “were the likely causes of the increased growth of blue-green algae’. Provincial government website said.
As the algae forms along the shoreline, it may begin to die and rot, turning a bright green hue and creating a sewer-like odor.
The lake has long contained high levels of algae since the last ice age, which ended about 10,000 years ago.
An 1873 report by biologist Livingston Stone confirmed that the lake is no novice when it comes to algal blooms.
“It is a singular fact … that the water of Clear Lake is never clear,” Stone told Congress at the time, according to the Lake County government website.
“It’s so cloudy, to use a mild word, that you can’t see a meter below the surface,” he said.
‘The color of the water is yellowish brown and varies infinitely with the varying light. The water has an earthy taste, like swamp water, and is reminiscent of moss and aquatic plants.
‘In fact, the bottom of the lake, except in deep places, is covered with a deep, dense moss, which sometimes rises to the surface, and often to such an extent in summer as to seriously impede the passage of boats through the water hinders. .’
His descriptions are similar to the conditions Clear Lake has experienced over the past twenty years as environmental conditions deteriorated.
The National Oceanic and Atmospheric Administration (NOAA) warned there is no way to slow or stop the growth of harmful algae because it is a ‘natural process’.
The only steps agencies can take are to develop tools and forecasts that identify harmful algal blooms, and NOAA said it is already studying harmful algal blooms (HABs) to find ways “to mitigate their effects, and to provide early warning of when and where flowering will occur’. prevent.’
DailyMail.com has contacted NASA for comment.