September 21, 2020

A time capsule on the frozen continent



Have you ever opened a book that had been closed for years? Smells old, yes, but something else. The humidity, the cellulose suffocated after several decades without seeing the sunlight. When all these aromas reach our nose they do not do it for good, they drag us against our will to a past time, they evoke in us something more than the image of the old book. They are, in a way, cameras of time. Things of our present that have been isolated for so long from the rest of the world, that in them the essence of a previous era remains. Books are an example, but in nature there are hundreds more. The rarity of animal species in Australia or Madagascar is due precisely to this isolation, which has allowed them to remain as they were thousands of years ago, without the complex evolutionary pressures of the continent.

However, the pages of the book are gradually impregnated with the air that surrounds it and the islands receive small settlers who, after a storm, had been pushed out to sea by manning branches and trunks. A true time capsule should be completely airtight and as we peek into it we should be able to see what the world was like when it was isolated. Fortunately, we know that these capsules exist and the queen of them all is in the most remote territory on the planet, the interior of Antarctica, almost 4,000 meters under the ice.

The biggest time capsule

In the early 1960s, the Soviets were engaged, among other things, in dynamiting Antarctic soil. It was the Soviet Antarctic Expedition and they had good reason to do so. If you imagine Antarctica as a snow desert, this article will not be the one to discuss it. There, the hills are not snowy, they are made of snow, so much that it covers anything from lakes to entire mountain ranges. To know the continental surface of Antarctica you have to figure out and see through all that solidified water and the best solution back then was something like a hybrid between an ultrasound and a mascletá.

These were seismic soundings in which the waves produced by the explosions were transmitted through the snow, ice and rock, bouncing differently in each one of them and returning them to the surface. Knowing how these waves have behaved during their journey, how they have deviated or how much they have been attenuated, we can infer what is under our feet. That’s more or less what geographer Andrei Kapitsa was doing when he found the largest time capsule in history.

At about 3700 meters deep the soil structure was suddenly changing. They were the limits of an underground lake, but not just any lake. Over time the measurements improved and we now know that, at 500 meters deep, 50 kilometers wide and 250 kilometers long, Lake Vostok is one of the largest lakes in the world. A time capsule completely isolated from the environment with space for 5,400 cubic kilometers of liquid water.

Under pressure

The possibility that these subglacial lakes might exist had been suspected for some years. It may seem strange that liquid water exists at those sub-zero temperatures, but the key lies in the depth. Under so many kilometers there is a lot of pressure, so much that the snow itself begins to melt. This and the high concentration of salts work its wonders and allow us to speak today of the largest subglacial lake in the world.

To tell the truth, between the snow and the lake there is a layer of ice formed approximately 15 million years ago. It is speculated that this was the moment when Lake Vostok was isolated, trapping within it a world from another era. However, we should not confuse this with the age of its waters. Part of the lake is gradually freezing, being supplied by liquid water that filters from other nearby snows, under similar pressures. This makes the water that is now inside it, at most, about 13,300 years old.

So, reviewing: we have a huge lake that has remained isolated for a very little 13,300 years, at temperatures below zero and where sunlight does not reach. It is not the ideal place to live, yet it seems that even such a dump could be teeming with life.

Extreme life

It is exciting to think that under so much ice life can exist, even if it is single-celled. However, it is even more so if we think of the icy moons of giant planets. Enceladus on Saturn and Europe on Jupiter they are satellites covered in ice and containing seas or even oceans of liquid water. These asmobiologists consider these moons to be the most likely places to find life without leaving our solar system. However, the distance and the excessive thickness of the ice make it very difficult to investigate your inner world in search of life, but Lake Vostok is a perfect substitute.

A long time ago, the Soviets already tried to make their way down to the lake, but the techniques were dangerous and drilling could spill antifreeze that would compromise the samples. If this was a sanctuary, any contamination could be dire. In other words: to make sure that there is something in there we need to make sure that we have not carried that something in our apparatus.

Precisely this is why the two measurements made to date are somewhat controversial. The first, carried out by the British and Americans, claimed to have detected thousands of different genetic sequences from all kinds of single-celled beings. The problem is that their first intention was not to collect samples, so their drilling systems were not designed to be sterilized with UV radiation. Its purpose was to extract cylinders of ice and capture trapped gases from them so that they could tell us about the atmosphere and climate of thousands of years ago. So Scott O. Rogers’ 2013 post is controversial to say the least.

The second was carried out by the same discoverers of the lake, the Russians, in this case with French collaboration. These found a few bacteria that could well be the result of contamination, but next to them was one never seen. Its uniqueness supports the idea that it could be an exclusive species of the lake.

Perhaps in the future we will be able to pilot drones in that ice sanctuary and verify that indeed there was a whole fauna of microorganisms reproducing in Lake Vostok. If we succeed, we will not only be talking about the roughness of life, capable of adapting to the most extreme conditions imaginable, but we will be instilling a little hope in our search for life beyond Earth, under the inhospitable surface of another. frozen world.

DON’T NECK IT:

  • The water in Lake Vostok is not 15 million years old, it is constantly being renewed and it is estimated that every 13,300 years it has completely changed.
  • The samples of genetic material obtained can be contaminations, so it is prudent to wait for more solid tests to affirm the existence of life in the lake.

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