2023-06-28 10:27:01
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[EN VIDÉO] In Antarctica, the flow of the Trooz glacier is accelerating A team of scientists from the University of Leeds (United Kingdom) and the University of Utrecht (Netherlands) has…
They spring from the Taylor Glacier in Antarctica. Waterfalls with the color red color which earned them the nickname of waterfalls of blood. A color which, at the time of their discovery in 1911, was first attributed to an algae. More recently, a study had revealed that the phenomenon could rather be due to the existence of a network of rivers and a sub-glacial lake – in which life had settled – carrying iron-rich salt water. Enough to allow this water to remain liquidliquid in this cold environment. And take a reddish color by oxidation oxidation of iron salts.
On closer inspection, a team of American researchers made an amazing discovery about it. They observed, in this water not quite like the others, a quantity of nanospheres. Spheres about 100 times smaller even than human red blood cells. Spheres rich in iron and which also contain many other elements. Siliconsilicon, calciumcalcium, aluminumaluminum or even sodiumsodium. All different spheres.
Better understand the other planets
And these nanospheres are not crystalline, the researchers report. This explains why they had not been detected with the conventional instruments used so far to study this water. Instruments dedicated to the examination of mineralminerals. Only the transmission electron microscope could update them.
The work of American researchers thus shows that the analyzes carried out by roversrovers sent to other planets could well prove to be incomplete. They might not be able to show the true nature of the materials on the surface of these planets. Especially in the case of cold planets, like Mars. And they might even miss some evidence of life on the red planet. In environments that would resemble those of the Taylor Glacier in Antarctica.
In Antarctica, a strange pocket of life isolated from the rest of the world
In Antarctica, micro-organismsmicro-organisms have managed to adapt, for more than a million years, to an environment totally devoid of lightlight, oxygen and heatheat. Their trick: breathe iron.
Article by Jean Etienne published on 04/22/2009
A pocket of seawater, trapped for 1.5 million years in Antarctica, under the Taylor Glacier (near Victoria Land), has just revealed a fascinating secret. This mass of water, with an average temperature of -10°C, never receives daylight, is devoid of oxygen and appears loaded with salt, iron and sulphates. Regularly, flows of red water coming from the depths of the glacier suggest the presence of red algae, a hypothesis to which the first scientists who explored the region agreed. But the absence of sulfidesulfides, which should have come from the metabolization of sulfursulfur by micro-organisms, had however invalidated this theory.
More recently, geomicrobiologist Jill Mikucki, from Harvard University in Cambridge, and her colleagues took a sample of these red effluents. A genetic analysis of the populations of bacteria bacteria has shown that they are close to species which, for respiration, exploit sulphates rather than oxygen. However, the dosage of oxygen isotope isotopes show, according to the authors, that these Antarctic bacteria do not use sulfates directly to breathe. Finally, the seawater sampled seems abnormally rich in ferrous iron (Fe2+). This excess would come from the bacteria themselves, which would transform ferric iron (Fe3+), which is insoluble, into ferrous iron. Conclusion of the biologists: the bacteria would use sulphates as catalystscatalysts to, literally, breathe iron, which would therefore play the role of oxygen.
A clue to the origin of life, not just on Earth
« When I started to analyze this water, which hadn’t seen the light of day for at least a million years, there was no trace of oxygen. I screamed Eureka when I made this discovery “recalls Jill Mikucki.
It is currently impossible to assess the amount of water contained in this pocket under the ice, but its depth is estimated at 400 meters while it would be at least 4 kilometers from the place where the red flows occur from time to time. another in the sea. When the level of the oceans fell more than 1.5 million years ago, a deposit of water was probably trapped, then covered by the Taylor glacier in formation.
Scientists believe that similar concentrations of life may have persisted in other places, especially during so-called episodes of snowball earth, a hypothetical but strongly suspected event over 600 million years ago, during which the Earth would have been completely covered in ice and snow. These eras would have seen the disappearance of the vast majority of life forms but would also have been the triggering factor for the evolution of the first complex life forms.
Exobiologists are also very interested in these atypical life forms, which could constitute a model of what could be discovered on inhospitable worlds or very different from Earth, such as Mars or the frozen oceans of Europa, one of the natural satellites of JupiterJupiter.
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