Antarctic sub to explore Lake Tahoe's depths

SOUTH LAKE TAHOE - Despite what Polar Plunge participants may tell you, Lake Tahoe is not the Antarctic.

But it will pretend to be in a little more than two months.

The maiden voyages of a 24-foot-long robotic submarine hosting an array of cameras, lights, sonar and sample-gathering "fingers" are scheduled for the lake during two weeks near the end of March.

The submarine is a key component in a multimillion-dollar, five-year investigation of melting near the base of the West Antarctic Ice Sheet.

Near the end of 2011, researchers will thread the submarine through a 3-foot drill hole melted through nearly 3,000 feet of the Ross Ice Shelf to gather information critical to climate modelers trying to predict future rises in sea levels due to global warming.

"The unique technology will allow scientists for the first time ever to observe melting and other conditions at the interface between seawater and the base of the glacial ice," according to a statement from Northern Illinois University, one of nine institutions involved in the research.

Substantial melting at the base of the ice shelf and ice sheet would lead to a more rapid sea-level rise than expected, according to the statement.

"We'll be investigating some of the last unexplored aquatic environments on the planet," said researcher Ross Powell in the statement. "One of our major objectives is to get to the bottom of the Ross Ice Shelf and West Antarctic Ice Sheet and see what's going on. We know the ice is melting there, but we don't know how fast."

During a phone interview last week, Powell said Lake Tahoe was chosen as the submarine's training ground because it's deep and relatively calm.

The submarine's Antarctic mission will take place in calm waters, and wave action experienced during ocean tests would have had the potential to damage delicate instrumentation, Powell said.

Lake Tahoe's proximity to Alameda, Calif., where the submarine was built by Deep Ocean Exploration and Research Marine, also made the lake a natural choice, Powell said.

The first phase of the submarine's local voyage will be to ensure the untested submarine and its instrumentation work properly, Powell said.

The second phase will include some local research.

The submarine will take a look at whether Lake Tahoe's invasive Asian clam population has spread from near shore areas into deeper regions of the lake, as well as examine the lake's seismic fault zones.

Examination of the faults, as well as landslides believed to be caused by historic earthquakes, will provide insight into the frequency and potential future seismic activity at the lake, said Richard McCarthy, the executive director of the California Seismic Safety Commission.

The commission contributed $50,000 to support the Lake Tahoe tests.

The information gathered in March also may be used to guide development in some areas of the basin in light of potential earthquake risk, McCarthy said.

Exact dates and locations of the Lake Tahoe tests have yet to be determined, although researchers are looking at sites near the UC Davis Tahoe Environmental Research Center in Incline Village, Powell said.

Those involved in the project are also working on setting up live streaming video of the submarine's Lake Tahoe exploration. Where it will be broadcast has yet to be determined.