Warming impact: Study looks at climate change and Tahoe
September 29, 2008
The effects of a changing climate are appearing in Lake Tahoe.
UC Davis researchers last week published the first evidence that a warming climate is impacting microscopic plant life in Tahoe ” the foundation of the ecosystem in the lake. If the changes continue, the effects could reverberate up the food chain to fish, birds, and land animals dependent on the species below them.
“This will definitely have an effect on zooplankton and fish species,” said Monika Winder, research associate at the UC Davis Tahoe Environmental Research Center, and the study’s lead author. “And it may indirectly effect water clarity and carbon cycling.”
What the researchers looked at were diatoms ” single-celled plants that both feed the aquatic food chain and store a substantial amount of carbon, Winder said.
And what they found was as the water warms, the difference in density increases, so less mixing of the lake occurs, Winder said.
With less mixing, larger, heavier diatoms sink while smaller, lighter ones stay higher up in the water column, she said.
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As the types of diatoms change, so do the species that eat them, and the impact could be amplified as it goes up the line to larger fish species and beyond, Winder said.
Exactly what this means for the lake’s fish and other wildlife isn’t yet known however, she said.
The smaller diatoms stay at the surface longer, reducing clarity and making Tahoe look greener, Winder said.
“The smaller diatoms will probably store less carbon ” but that will require additional research,” Winder said.
Carbon’s potential role in climate change as a greenhouse gas has some scientists interested in the storage capacity of plant species from forests to plankton like diatoms.
The study, “Lake warming favors small-sized planktonic diatom species,” co-authored by John Reuter, associated director of the UC Davis Tahoe Environmental Research Center, was published Sept. 24.
It can be found at journals.royalsociety.org.