QUICK FACTS
Where is he? Pyramid Lake, Nevada [40.063141310, -119.561560320]
What’s in the photo? A massive proliferation of toxic cyanobacteria swirling in the lake
Which satellite took the photo? Landsat9
When was it taken? October 8, 2024
This striking satellite photo shows an exceptionally dense and toxic algal bloom swirling in the waters of Pyramid Lake, Nevada. Some experts estimate that algae has existed in the lake for at least 9,000 years.
The lake is fed by a single river, but it is endorheic, meaning it has no flow. As a result, its salinity is much higher than most lakes, as excess water evaporates, leaving behind its dissolved salts. The lake is also slightly alkaline and has a pH of around 9, which is roughly equivalent to baking soda.
Pyramid Lake experiences annual algae blooms between September and October, due to warmer temperatures and increased nutrient availability. The predominant algae species is Spumigenic nodularwhich is a nitrogen-fixing blue-green cyanobacteria that thrives in high salinity waters, according to NASA Earth Observatory.
But the 2024 bloom, captured in this satellite image, was one of the most extreme in recent memory. It peaked on October 15, about a week after this photo was taken. We do not yet know why this flowering was so intense.
Related: Check out all the best images of Earth from space
N. spumigena has the potential to produce toxins, such as nodularin, which can affect the liver and cause other adverse health effects in humans and other animals. During the 2024 flowering, local authorities I warned people not to let their animals near the water.
Pyramid Lake was once part of a much larger prehistoric body of water, known as Lake Lahontan, which covered an area of approximately 8,000 square miles (21,000 square km), approximately 45 times larger than Pyramid Lake.
This ancient lake was affected by climate change at the end of the last ice age, or Pleistocene Epochwhich ended around 12,000 years ago. About 3,000 years later, Lahontan had all but disappeared, leaving Pyramid Lake as its largest remnant.
Today, Pyramid Lake is known for a series of pillar-shaped calcium carbonate formations, known as tuffs, that developed from the receding waters of Lake Lahontan between 26,000 and 13,000 years ago, according to the United States Geological Survey. (This includes the pyramid-shaped structure that gives the lake its name.)
A 1990 study analyzed trends over 15 consecutive years N. spumigena bloomed in Pyramid Lake between 1972 and 1986. Researchers hypothesize that cyanobacteria once flourished in Lake Lahontan and may have persisted in its remaining waters ever since.
Pyramid Lake is also home to the cui-ui (Cujus chasmists) – an endangered species of sucker found nowhere else on Earth. These fish mainly feed on algae, such as N. spumigenaand also probably inhabited Lake Lahontan.
