University of Tennessee, Knoxville, research finds life can persist in a cold, dark world. A UT microbiology assistant professor was part of a team that examined waters and sediments from a shallow lake deep beneath the Antarctic ice sheet and found the extreme environment supports microbial ecosystems.
The National Science Foundation-funded research by Jill Mikucki and her colleagues has implications for life in other extreme environments, both on Earth and in the solar system. The findings are published in the current edition of the science journal Nature.
Analysis of samples taken from Subglacial Lake Whillans, which is under 800 meters of ice, shows that the lake "supports a metabolically active and...diverse ecosystem that functions in the dark at subzero temperatures," according to the authors.
The NSF project, called Whillans Ice Stream Subglacial Access Research Drilling, or WISSARD, made scientific and engineering history in late January 2013 when the researchers retrieved water and sediment samples from Subglacial Lake Whillans that had been isolated from direct contact with the atmosphere for at least many thousands of years.
Previous research at Subglacial Lake Vostok, the largest subglacial lake in Antarctica, has been called into question due to potential contamination, primarily from hydrocarbon-based drilling fluid. To avoid contamination concerns, the team used a novel clean hot-water drill technology to directly obtain samples from the waters and sediments that were uncontaminated by the drilling itself.
"Because Antarctica is basically a microbial continent, exploring below its thick ice sheet can help us understand how life has evolved to survive in cold darkness. I hope our findings motivate new research on the role of these extreme microorganisms in the function of our planet and other icy worlds in our solar system," said Mikucki.
Subglacial Lake Whillans is part of a network of major reservoirs under the Whillans Ice Stream. The researchers say their data shows that through this network's connections to the waters surrounding Antarctica, the microbial ecosystems influence the chemical and biological composition of the Southern Ocean which encircles the continent.
"Given the prevalence of subglacial water in Antarctica, our data...lead us to believe that aquatic microbial systems are common features of the subsurface environment that exists beneath the...Antarctic Ice Sheet," wrote the authors.
Co-authors on the paper include researchers from Montana State University, the University of Venice in Italy, the Scripps Institution of Oceanography, St. Olaf College in Minnesota and Aberystwyth University in the United Kingdom. Mikucki will return to the Whillans Ice Stream with UT graduate student Alicia Purcell this December.
NASA's Cryospheric Sciences Program, the National Oceanic and Atmospheric Administration, and the private Gordon and Betty Moore Foundation also provided support for the project.