Hello and welcome to my new video. Bacteria survive in the harsh conditions of the Andean lakes of Argentina among high concentrations of arsenic. In some of the most remote areas of our planet, scientists are examining how life can persist in the form of tiny microbes that inhabit a niche that would be fatal to the vast majority of organisms on Earth.
Living off toxic substances like arsenic, or in oxygen-free zones, these hardy microbes metabolise food and nutrients in completely different ways from most plants, animals and humans. Some move and metabolise so slowly, for example, that until recently scientists did not even consider them to be alive.
The harsh environments where they live are similar to conditions found on Mars and other planets, and by furthering our understanding of how these microbial communities work, space geobiologists will be better equipped to identify signs of extra-terrestrial life.
Dr Amedea Perfumo of the GFZ German Research Centre for Geosciences leads the EU-funded BIOFROST project, which is investigating how organisms survive in the deep biosphere of Earth’s permafrost, where temperatures are sub-zero and there is a lack of oxygen.
These anoxic and frozen conditions are extremely relevant for space exploration. It’s an analogue for Mars,’ she said. It’s about finding what the limits for life on Earth are under the most similar conditions to space and seeing if we can have a better interpretation of what might come out from a space mission.
BIOFROST focused on building up a so-called on-filter analytic pipeline, where information about live bacteria, such as how many there are of which type, how active they are and how they interact with each other are extracted from the permafrost sediment and collected onto a special gold-platinum coated filter.
I am supported by some of the most forefront techniques, which include NanoSIMS and nano-spectroscopy, and I hope, in particular, to provide scientific evidence to the basic functioning of a cell under such extreme conditions and how this impacts on the permafrost’s ecosystem functioning, said Dr Perfumo. The permafrost microorganisms being studied by Dr Perfumo have developed unique adaptations to their freezing, oxygen-free zones. Their metabolism is so slow, for example, that it is only recently that technology has become sophisticated enough to detect that the organisms are even alive.
Ecological adaptation can come at a cost, however. Because they’ve evolved to fit so perfectly into their niche, any kind of temperature change can spell trouble for the organisms. In previous experiments, Dr Perfumo found that when the heat was turned up by only 5 degrees Celsius, the bacteria died.
This shows a very low tolerance for change in environmental conditions, unlike many other kinds of bacteria. The various species of bacteria that we tend to find at room temperatures, for example, need to be able to survive fluctuating weather conditions, whereas deep permafrost bacteria are generally guaranteed to live at constant, though very cold, temperatures.
High up in the Andean lakes of Argentina, researchers are exploring another so called extremophile organism bacteria that survive in high concentrations of arsenic. The World Health Organization recommends that drinking water should have no more than 10 micrograms of arsenic per litre, but these lakes contain four or five orders of magnitude more.
The conditions in fact mimic life on prehistoric Earth. ‘When you are there, it’s like you are on Earth 3 500 million years ago,’ says Dr Maria Sancho-Tomas of the Institut de Physique du Globe de Paris, France, who leads the ASLIFE project to investigate the bacteria. ‘It’s amazing. If you look at the landscape, it’s like Mars.’
Biologists are collecting samples of structures created by microorganisms in Argentina, where conditions are like those on prehistoric Earth. Thank you for watching.
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