Sarah Stewart Johnson (right), assistant professor in the biology department and the Science, Technology and International Affairs program, and undergraduate Angela Bai (C’17) are two members of the Georgetown team headed to Antarctica later this month for research that may one day help solve the question of whether there was ever life on Mars.

A Georgetown professor is leading a National Science Foundation-funded expedition to Antarctica later this month that may one day help solve the question of whether there was ever life on Mars.

Sarah Stewart Johnson, assistant professor in the biology department and the Science, Technology and International Affairs program, is teaming up with undergraduate Angela Bai (C’17), post-doctoral fellow Elena Zaikova and David Goerlitz of the Lombardi Comprehensive Cancer Center to conduct the first-ever DNA sequencing on the continent.

The work, which will begin after Thanksgiving and last for about a month, takes place in the McMurdo Dry Valleys, just across the sound from the U.S. Antarctic Program’s main base at McMurdo Station.

CELL SURVIVAL

“We’re testing a series of questions about the nature of long-term cell survival under cold and hyper-arid conditions,” says Johnson, also a visiting scientist at the NASA’s Goddard Space Flight Center and a member of NASA's Curiosity Rover Science Team.

The McMurdo Dry Valleys are home to some of the most physically and chemically extreme environmental conditions in the world. The Georgetown team will study whether microbes within ice-covered lakes can survive desiccation as the lakes retreat, and if so, how.

“Mars and Earth used to be much more similar,” notes Johnson, who teaches courses in geobiology as well as planetary science. “Like the Earth, Mars once had lakes, but not anymore. Because it’s smaller and further from the sun than Earth, it cooled down more rapidly.”

“It also lost its protective magnetic field and most of its atmosphere, and now is bitterly cold and extremely arid,” she adds. “If life did evolve there, what’s become of it?”

Johnson says that Antarctica is the “coldest, driest place on Earth.”

“We believe the paleolakes there provide an unrivaled opportunity to investigate fundamental questions about the persistence of life,” she explains.

EXPLORING OTHER WORLDS

Johnson, a Rhodes scholar with a Ph.D. in planetary science from MIT, says she first became interested in her field as a child in Kentucky, where her father was an amateur geologist and astronomer.

In her first year at Washington University in St. Louis, she worked with a professor on the prototype for the Mars Spirit and Opportunity rovers. She was part of a team that went out into the Mojave Desert to take measurements.

“I fell completely in love with the idea of exploring other worlds,” she says

“Planetary science is a field that’s really wide open. There’s so much left to discover. In some ways it’s like being an earth scientist 100 years ago.”

Coincidentally, Georgetown Provost Robert Groves will be in Antarctica at the same time that Johnson’s group is conducting research.

As a member of the National Science Board, which governs NSF, he will be part of a team inspecting two of the three Antarctica science operations – McMurdo and the South Pole.

Source: https://www.georgetown.edu/sarah-johnson-antarctica-trip