Unlocking Secrets of Antarctic Microbes: New Research Methods Simplify Study
Thanks to an innovative platform for scientific exploration in Antarctica's most remote regions, the origins of Antarctic bacteria and the bacterial communities trapped in the snow and ice over the past 40-50 years are now being deciphered. WindSled, a mobile and versatile scientific base, enables the development of cutting-edge science with minimal environmental impact. Researchers can now describe microbial life from the air to depths of up to 4 metres in the ice, in the most inhospitable place on Earth. And in doing so, approach what life could be on other planets.
A lab to imagine life on other planets
The Antarctic Plateau, a vast expanse of ice and snow more than 3000 metres above sea level, is one of the most extreme environments on Earth, with -89.2°C being the lowest recorded temperature there (although it is estimated it could be as low as -93.2°C). It is, at the same time, one of the most arid places on the planet.
This environment is perhaps the best terrestrial analogue for studying the possibility of life on other worlds, such as the icy moons Europa (Jupiter) and Enceladus (Saturn), or the large icy areas of the planet Mars. This makes the Antarctic Plateau an ideal place to develop instrumentation for astrobiological purposes, such as the Life Detector Chip”, says Professor Victor Parro, INTA researcher at the Centro de Astrobiología (CAB), INTA-CSIC.
The combination of extreme cold and dryness makes it a Mars-like environment, where the average annual surface temperature near the equator is -58ºC and the atmospheric water vapour content is negligible. As on Mars, the water on the Antarctic Plateau is physically in the form of ice or vapour, but rarely in a liquid state.
Logistical constraints, cold, remoteness and altitude make it difficult to access the Antarctic plateau for sampling and in situ studies. The use of heavy vehicles, with combustion engines, is expensive, polluting, inefficient and logistically complex to travel long distances. But now, an international team led by the Centro de Astrobiología (CAB), CSIC-INTA, and the Universidad Autónoma de Madrid shows how the use of a lighter platform for scientific exploration is helping unlock the secrets of Antarctic microbial life in a freshly published, open source, Nature Communications (Springer) article:
WindSled allows us to go to the most remote places in Antarctica and study under what conditions liquid water can form in a frozen desert, for example through the deliquescence of certain salts, to understand similar processes on Mars. We have shown that at certain times along the more than 2500 km travelled, such deliquescent phenomena are possible and could provide water to maintain minimal biological activity. Perhaps similar phenomena can occur in some regions of Mars”, says Dr Alfonso F. Davila, a researcher at NASA’s Ames Center in California.
The last pristine environment on Earth
The Antarctic plateau is considered the last pristine environment on Earth. Here, the wind - as a means of transporting deposited particles, has been proposed as the main cause of input and distribution of life, nutrients, as well as pollutants.
During the 2018-2019 campaign to the Antarctic Plateau, four well-trained crew members travelled 2,538 km across the western sector of the Antarctic Plateau, from the vicinity of Novolazarevskaya Station to the Fuji Dome (>3,500 m altitude). The WindSled carried 200 kg of scientific instrumentation to conduct multiple sampling and in situ science experiments, including the detection of microorganisms.
The equipment included a portable immunosensor (LDChip) designed for the detection of life in planetary exploration, an aerosol and airborne biological material collector capable of operating in the extreme conditions of the expedition, and continuous monitoring of potential deliquescence events along the transect.
This work demonstrates the value and importance of using relatively inexpensive, emission-free sampling platforms even in the most remote parts of Antarctica, where in situ observations are lacking, but are essential for understanding current climate change and predicting future climate change and its impacts”, says Professor Mayewski, director of the Climate Change Institute at the University of Maine, USA, and co-author of the paper.
An archive of past climatic and atmospheric events
Low temperature and absolute humidity, coupled with high UV radiation during the summer, scarcity of liquid water and scarcity of nutrients, make the Antarctic Plateau an excellent natural laboratory for investigating the extremes of life on Earth. The ice here represents an archive of past climatic and atmospheric events, as well as the historical presence and accumulation of biological material.
Until now, few studies have focused on the microbiology of the high Antarctic Plateau, and those that have done so have only explored surface snow up to 30 cm deep. But things are different now: "We describe the first microbial profile from air to 4 m depth of snow/ice on the Antarctic Plateau at three significantly distant locations, deciphering the bacterial communities trapped in snow/ice over the last 40-50 years. This is the first time that microorganisms have been collected and identified from the air on the Antarctic Plateau”, says Prof. Antonio Quesada, Universidad Autónoma de Madrid.
Transport vectors, such as snow/ ice particles and windblown bioaerosols, can condition the biogeographic distribution of the bioburden, depending on the prevailing winds, as the authors of this paper have shown. The use of the LDChip biochip to detect life or traces of life during the campaign made it possible to detect the presence of certain microorganisms, including cyanobacteria, in ice core samples.
This is not only the first time that we have been able to obtain samples of the micro-organisms that circulate in the air of this immense territory of the planet, but also the first time that we have used the new collectors and the statistical instrument that we have had to invent to understand their origin”, explains Prof. Ana Justel, Universidad Autónoma de Madrid.
Once in the laboratory, a new species of cyanobacteria of the genus Gloeocapsopsis was isolated and cultured from one of the core samples from a depth of 3 to 4 m, with an estimated age of 30-40 years. This is a further demonstration of the great capacity of the LDChip in the search for life in planetary exploration”, says Dr Mercedes Moreno, researcher of the INTA SOLID-LDChip team at the CAB.
Undoubtedly, the WindSled is a truly mobile, zero-emission, highly manned and loaded scientific platform, allowing unprecedented and planet-friendly research to be conducted on the unexplored Antarctic plateau and other large ice masses. Using the Wind Sled on a regular basis on the world's frozen plateaus could mean access to barely studied ecosystems, putting our researchers at the forefront of the study of the cryosphere.
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