Lake Tahoe is famous for its magnificent blue color and incredible clarity. These features have turned the lake in a landmark of the country being one of the most beautiful lakes in the United States. It has been said that the color of the lake is caused by the presence of algae, but a new study indicates that it is in fact due to the lack of it. Moreover the color of Lake Tahoe has nothing to do with its clearness.
Researcher Shohei Watanabe from University of California, Davis created a Blueness index as a way to measure the factors which contributed to the magnificent color of the lake. For this he used an instrument which captures light and information from a NASA Jet Propulsion Lab research buoy.
Watanabe explained that they have been dealing with this problem the wrong way when they assumed that the clearer the lake was the bluer it turned. Now it was discovered that the lower the algal concentration was the bluer the lake was. So water clearness has nothing to do with the color.
Using the research buoy the scientists gathered data above the lake and analyzed the connection between color and clarity using hyperspectral radiometers.
While blueness is influenced by algal concentration clarity is influenced by sediment. Algal concentration is controlled by the level of nutrients, meaning phosphorus and nitrogen. The less nutrient the bluer the lake.
Researchers observed that at times Lake Tahoe was clearer and less blue and other times the other way around. Experts say that this change is caused by the variations in the levels of algae, sediments and nutrients which tend to be different from one season to another. In summer time, which coincides with the period of time when most tourists come to visit Lake Tahoe the lake is the bluest.
Geoffrey Schladow, the director of Tahoe Environmental Research Center at UC Davis, remarked:
Less nutrients washed into lake, nutrients that helped algae to grow. So nature has shown us what happens if nutrients get into the lake. In that way, Lake Tahoe has shown us what it needs to be blue and clear again.”
Image Source: laketahoechambers.com