For several years, researchers have worked to determine how life can be sustained in extraterrestrial space, known for conditions of extreme heat and cold. A recent study in the journal Extremophiles, conducted on Deception Island in Antarctica, provides answers to some of these questions.
At Deception Island, both volcanoes and glaciers lie in close proximity, creating regions of prominent temperature differences over a short distance. The extreme conditions on the island range from 98 to 0 degrees Celsius due to the presence of active fumaroles (openings near the volcano), where the temperatures reach values of 100 degrees Celsius, and glaciers, where temperatures drop to 0 degrees Celsius. The close proximity of volcanoes and glaciers makes Deception Island an interesting analogue for extraterrestrial environments, including Mars’s extinct volcanoes and Enceladus’s cryovolcanoes.
This polar location allowed researchers to recover microorganisms that have the ability to survive under very hot conditions beyond their growing range of temperature. The study explored the microorganisms surviving in these conditions and tested their survival potential in astrobiological conditions.
To isolate the microorganisms surviving in these extreme environments, the scientists collected sediment samples from the volcano on Deception Island during the XXXII Brazilian Antarctic Expedition from December 2013 to January 2014 at the geothermally active sites of Fumarole Bay and Whalers Bay.
Through DNA-sequencing techniques, scientists estimated the total number of bacterial cells in the sediment. To isolate microbes that have the ability to survive in extreme conditions, the samples were incubated in two different temperatures, 4 degrees Celsius and 60 degrees Celsius. The samples were allowed to grow for about two weeks. A total of 147 colonies were successfully obtained from these procedures, and they were subjected to further molecular analyses to determine the species and the genera of the microorganisms.
In addition, the samples were subjected to ultraviolet radiation that is present on Mars, called UV-C radiation. UV-C radiation, although not present on Earth, composes a significant proportion of UV spectra on the Martian surface, due to the rarified atmosphere of the planet.
Scientists from the study found that the microorganisms were able to survive these conditions despite the fact that these range of temperatures were beyond the range in which they normally grow. The study also found that these microorganisms adapted to surviving under these temperatures by forming spores around their membranes, which enabled them to resist the extreme range of temperatures. These structures suggested to the researchers that there could be a similar adaptation strategy to enable the survival of microbial life on Martian surfaces.
The study provided interesting insights into strategies deployed by microorganisms to survive in conditions that resemble the Martian surface. The initial data from the study suggest the thermophiles isolated by the researchers have the potential to be further explored in astrobiological studies.
Sruti Devendran holds a Master’s degree in Climate and Society from Columbia University. She did her undergraduate degree in biotechnology in India. She is curious about the potential possibility of life in extraterrestrial space. She enjoys writing and cares about issues affecting low income communities impacted by climate change.