What An Antarctic Island Tells Us about Mars

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.

Pendulum Cove, Deception Island, Antarctica (Source: Delphinidaesy/Flickr).

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.

Deception Island, Antarctica (Source: Melissa Scott/Flickr).

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.

On top of the volcano crater on Deception Island (Source: staigue/Flickr).

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.

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Could Cryoconites Hold the Secrets to Extraterrestrial Life?

In recent years, scientists have found other locations on planets, moons and exoplanets where life might exist. Different animals and organisms like tardigrades (eight-legged microscopic animals commonly known as water bears) have also been sent into space to explore the conditions for survival away from Earth. However, a recent paper published in the journal Contemporary Trends in Geoscience argues that we can look closer to home to understand survival strategies of extraterrestrial life.

More concretely, the authors propose we look to glacier cryoconites, which are granular or spherical mineral particles aggregated with microorganisms like cyanobacteria, algae, fungi, tardigrades and rotifera (another type of multicellular, microscopic animal). Glaciers are among the most extreme environments on Earth due to the high levels of ultraviolet (UV) radiation received and the permanently cold conditions. These factors make them analogous to icy planets or moons.

(Clockwise from top left) An ice sheet in Greenland, cryoconite holes, cryoconite granules, and cryconite granules in high resolution (Source: Zawierucha et al., 2017).

The associations of cryoconites and microorganisms on glaciers are held together in biofilms by extracellular polymeric substances (natural polymers of high molecular weight) secreted by cyanobacteria. They exist as sediment or in cryoconite holes (water-filled reservoirs with cryoconite sediment on the floor) on glacier surfaces.

Cryoconites have been found on every glacier where researchers have looked for them. Cryoconite holes form due to the darkening of color (also termed a decrease in the albedo, or reflectivity of solar radiation) of cryoconite-covered surfaces. The darker color leads to greater absorption of radiation, with an associated warming and increasing melt rates.

“Today we think that simple life forms might have survived on Mars in glacial refugia or under the surface. They can and could have evolved on Saturn and Jupiter’s icy moons,” Krzysztof Zawierucha, the lead author from Adam Mickiewicz University in Poland, shared with GlacierHub. “Imagine a multicellular organism, even a microscopic one, which is able to live and reproduce on an icy moon… It is a biotechnological volcano.”

Earth’s glaciers could be analogous to environments like floating ice on Europa, one of Jupiter’s moons (Source: NASA).

Organisms that live in glaciated regions are adapted to survive in extreme conditions and could provide insights into the survival strategies of extraterrestrial life. Some possess lipids (organic compounds that are not water-soluble), and produce proteins and extracellular polymeric substances that protect them from freezing and drying. Others are able to enter cryptobiotic states in which metabolic activity is reduced to an undetectable level, allowing them to survive extremely harsh conditions.

The microorganisms in cryoconites cooperate and compete, affecting each other’s survival responses. Therefore, previous astrobiological studies, which have only been conducted on single strains of microorganisms, may not reflect the true survival mechanisms of these microorganisms.

Tardigrades can undergo cryptobiosis and survive in the vacuum of space (Source: UNC Chapel Hill/Creative Commons).

In addition, previous astrobiological studies involving some of these microorganisms used terrestrial or limno-terrestrial (moist terrestrial environments that go through periods of immersion and desiccation) taxa, such as moss cushions, which are less likely to be well-adapted to icy planets than their glacier-dwelling cousins.

Tardigrades found in cryoconite have black pigmentation, which probably protects them from high UV radiation. Along with tardigrades, glacier-dwelling rotifera, specifically Bdelloidea, also possess a great ability to repair DNA damage, which confers high resistance to UV radiation. Both may also be better adapted to surviving in constantly near-freezing conditions than terrestrial forms.

“So far, a number of processes analogous to those on Mars and other planets or moons have been found in the McMurdo Dry Valley as well as other dry valleys or brines in sea ice, both of which were considered to be extraterrestrial ecosystem analoguos. There is a great body of evidence that some bacteria and microscopic animals like tardigrades may survive under Martian conditions,” Zawierucha explained.

“Of course, to survive does not mean to be active and to reproduce. Undoubtedly, however, it triggers consideration regarding life beyond Earth, especially in close proximity or connection with permafrost or ice,” he added.

As such, further research about cryoconites could provide insight to mechanisms that enable organisms to survive such extreme conditions. At the same time, cryoconites could also be used in future astrobiological studies to understand how life on other planets functions.

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