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Scientists Discover What Makes Lake Tahoe Blue

Karin Higgins / UC Davis

Scientists in the UC Davis Tahoe Environmental Research Center's research vessel check on a NASA research buoy that collects data about Lake Tahoe.

Karin Higgins / UC Davis

Scientists have long thought that the blueness of Lake Tahoe was due to the lake’s clarity.

But a new study shows that algae plays an important role.

For the past three years, UC Davis researchers have been measuring the degree of blueness in Lake Tahoe using a NASA research buoy. They compared those results with the lake’s clarity and found something surprising.

“Clarity and blueness are controlled by very different things," says Geoffrey Schladow with the UC Davis Tahoe Environmental Research Center.

“Clarity is controlled by very fine particles, dust and clay and silt that are washed into the lake. The blueness is controlled by algae,” says Schladow.


Emerald Bay, Lake Tahoe, Photo by Karin Higgins / UC Davis

The less algae, the bluer the lake. Stormwater runoff carries nutrients that spawn algae growth. Schladow says that’s not happening in the drought which gives him hope for restoration efforts.
“What we’re seeing is how the lake responds. We’re seeing it's becoming bluer, it’s becoming clearer and that’s evidence that the strategies that are being proposed will actually work,” he says.
The State Of the Lake Report also found that average surface temperatures reached an all time high, including the highest ever recorded during the winter


Amy Quinton

Environment Reporter

Amy came to Sacramento from New Hampshire Public Radio (NHPR) where she was Environment Reporter. Amy has also reported for NPR member stations WFAE in Charlotte, WAMU in Washington D.C. and American Public Media's "Marketplace."  Read Full Bio