A flourishing ecosystem has been found a mile and a half beneath Antarctic ice in a lake cut off from the outside world for millions of years.
The discovery was made by US scientists who found tiny organisms that generate energy for growth from the natural ammonium and methane in the environment.
This is the first direct evidence that life can be found deep below the Antarctic ice sheet and could have implications for finding life in extreme environments in our solar system.
‘We were able to prove unequivocally to the world that Antarctica is not a dead continent,’ said lead scientist Professor John Priscu, from Montana State University.
Many of the organisms found belong to a primitive extended family of microbes, distinct from bacteria, called the Archaea.
The team drilled through half a mile of ice to reach the sub-glacial Lake Whillans in January last year.
Archaea form one of the three great ‘domains’ of life on Earth, the other two being bacteria and eukayotes – organisms with their DNA contained in a cell nucleus – to which humans belong.
Many of the sub-glacial archaea survived by harnessing energy in the chemical bonds of ammonium, the research showed.
Another group of micro-organisms in the same area relied on the energy and methane locked into carbon to survive.
The scientists insisted that the microbes originated in Lake Whillans and were not introduced by contaminated equipment.
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.
‘We went to great extremes to ensure that we did not contaminate one of the most pristine environments on our planet while at the same time ensuring that our samples were of the highest integrity,’ said Professor Priscu.
‘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,’ said Jill Mikucki from the University of Tennessee, who was also involved in the project.
‘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.’