Lake Tahoe's Clarity Threatened As Bottom-Dwelling Creatures Disappear


Researchers at Lake Tahoe are trying to figure out why some of the smallest creatures and plants at the bottom of the lake are disappearing at an amazing rate. Populations of worms, stoneflies and bottom shrimp are declining to levels measured in the 1960s.

Sudeep Chandra, an associate professor with the Biology department and the College of Science at the University of Nevada, Reno, told KNPR the crashing of populations is absolutely dramatic.

“The organisms that are in decline are called benthic invertebrates,” Chandra said. “They are the size of your thumbnail or smaller. Most of these organisms are found at Lake Tahoe or endemic to the system.”

He said there are eight animals total in decline, including the stonefly and flatworms. Chandra added that the health of the bottom of Lake Tahoe was crucial because the “bottom of lakes are important habitats for processing nutrients and organic matter.”

Although researchers do not exactly why the populations are declining, the two most likely explanations are that the plants that the creatures live in are dying off because they are not getting the light needed to survive due to the decline of the lake's clarity and that non-native, invasive species like the crawfish are devouring the plants that are the creatures' habitat. 

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“Changes at the bottom may be an indication of things to come in the future,” Chandra said. “These eight declining animals are multiple canaries in the coal mine indicating that we need to think (of) the functioning of the entire Lake Tahoe ecosystem.


Sudeep Chandra, an associate professor, Biology department and the College of Science at the University of Nevada, Reno.

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