"I can't believe someone's letting me pilot a little submersible!" But there she was, UC Davis geology graduate student Bekah Shepard, exploring Pavilion Lake, British Columbia, as part of an expedition to study strange life forms that could give clues to the history of life on Earth and other planets.

The researchers used a pair of one-person submersibles to map and sample microbialites -- formations of living microbes and minerals thought to be similar to some of the earliest forms of life on Earth.

Darlene Lim from the National Aeronautics and Space Administration's Ames Research Center led the team, which also included UC Davis undergraduate Natalie Stork.

With the submersibles, the team reached the deepest parts of the lake (about 180 feet), after earlier doing their research by scuba diving and with remote-controlled vehicles.

Shepard and Stork have been studying for their doctorates with UC Davis geology professor Dawn Sumner, who studies ancient forms of life on Earth and how their billion-year-old fossils can be distinguished from purely mineral traces. The same knowledge could be applied to look for evidence of life on other planets, notably Mars.

The expeditionary team also included Canadian astronaut Dave Williams, now a professor of surgery at McMaster University, and NASA astronaut Michael Gernhardt.

Hear from Shepard in a NewsWatch video.

-- Andy Fell