WARMING ADDS TO TAHOE'S WORRIES: A new UC Davis study predicts that climate change will irreversibly alter water circulation in Lake Tahoe, radically changing the conditions for plants and fish in the lake -- and it could happen in 10 years. One likely result would be a warmer lake overall, with fewer cold-water native fish, and more invasive species, such as large-mouth bass, bluegill and carp.

Still unclear is how the changes would affect the lake's phenomenal clarity and cobalt-blue color, which have helped to make the Tahoe Basin an international vacation destination.

"What we expect is that deep mixing of Lake Tahoe's water layers will become less frequent, even nonexistent, depleting the bottom waters of oxygen. This will result in major, permanent disruption to the entire lake food web," said Geoffrey Schladow, director of UC Davis' Tahoe Environmental Research Center.

"A permanently stratified Lake Tahoe becomes just like any other lake or pond. It is no longer this unique, effervescent jewel, the finest example of nature's grandeur."

Schladow said research is ongoing to determine if lowered global greenhouse-gas emissions would significantly slow the lake's decline, or even prevent it.

-- Sylvia Wright

LYME DISEASE BACTERIA CAN LINGER: The bacteria that cause Lyme disease, the most common tick-borne illness in the United States, can linger in mouse tissues long after a full round of antibiotic treatment is completed, UC Davis researchers reported in the March issue of the journal Antimicrobial Agents and Chemotherapy.

"It's important to note that the numbers of residual bacteria identified in this study were very low and there was no evidence that they were causing inflammation," said Stephen Barthold, director of the Center for Comparative Medicine. "Their presence shouldn't be misconstrued as a sign of chronic disease."

Nor does the finding support extended use of antibiotics to treat Lyme disease in people.

However, the study sets the stage for controlled laboratory research investigating potential therapies for persistent Lyme disease infections.

-- Pat Bailey