Lake Tahoe looks stunningly blue because of the algal concentration that determines the color of water, a new study conducted by University of California (UC) researchers suggested.

For a very long time, it has been believed that iconic blue hue of Lake Tahoe is because of the clarity of its water. But UC concluded that the blueness of the lake comes from the amount of algae in the water instead of its clarity.

Shohei Watanabe, a postdoctoral researcher from UC Davis, concluded that the lower the algal concentration, the bluer the lake. Watanabe came up that conclusion after a Blueness Index was created with the help of NASA-JPL research buoy and Lake Tahoe’s color was quantified for the first time.

The researchers were surprised to find no connection between clarity and blueness of the lake.

However, Watanabe stressed, “This does not mean that clarity should be dismissed. Rather, it shows that algae concentrations and nutrient input should be managed more closely to truly keep Tahoe blue and clear.”

There were times when Lake Tahoe was clearer and less blue and when it less clear and deep blue. The change takes place due to changes in sediments, nutrients and algal production with changes in the season.

Geoffrey Schladow, director of Tahoe Environmental Research Center at UC Davis, described the findings as “remarkable achievement” in terms of better understanding how Lake Tahoe works.