Although it is not the closest outer point to the center of the Earth, the Mariana Trench is the closest place to the depths of hell that we have been to. What can live down there?
The deepest recorded point of this chasm is located at more than 11,000 meters . And the human being has come almost to the end, three times! This is what we have learned from this huge and almost unfathomable pit.
In the jaws of hell
More than a thousand atmospheres, barely four degrees and total darkness : if this doesn’t look like the most gruesome hell we can imagine, nothing will. And yet, even here we find life. East of the Mariana Islands in the Philippines is this crescent-shaped chasm.
This pit has the deepest point on Earth, although not the closest to its center due to the irregularity of our geoid. Specifically, with 11,034 meters below the surface. It is so deep that, if we put Mount Everest inside it, it would still have another 2,000 meters to go before it can approach the surface.
In his bed we have been, human beings, up to three times. The first in 1960, when the famous Aguste Piccard, together with Don Walsh, a former military man, reached 10,911 meters aboard a bathyscaphe, in the “Challenger Abyss”. In 2012, filmmaker James Cameron managed to descend, alone, to the not inconsiderable 10,908 meters, a little above the Piccard mark.
A while ago, the record was broken by Victor Vescovo, reaching 10,928 meters. His impression was quite strong: “It was very disappointing to see the obvious human contamination in the deepest point of the ocean,” he told the press. But, in addition to plastic pollution, the truth is that the deepest natural point on Earth, a barren scene, almost frozen, with dense water like nowhere else and absolute blackness, has more to show.
What or who lives in the deepest part of the ocean?
James Cameron described his immersion as a journey into the most immense solitude. But it is not true. Although few beings are capable of surviving such extremely extreme conditions, the truth is that there are. In 2011 it was discovered that the bottom of the abyss was hosting xenophiophores. These beings may look like sea sponges or other animals, at first glance.
But, in reality, they are microorganisms organized in “pseudostructures”, that is, forms with a certain organization that appear to be more complex than they are. These beings are highly specialized to live in impossible conditions. They are extremely delicate and there has not been a single collection that has not ended their life. At the moment, it seems impossible to study them “in vivo” comfortably.
Much of what we know about these organisms is from their relatives. Xenophyophorea is a class of protists, single-celled organisms among which are amoebas. The xenophiophores are spread over all the fairy bottoms (below 6,000 meters) that we know of. In themselves, this class of protists are very difficult to handle and remain a real mystery in many respects.
Due to their large numbers, marine biologists speculate that they play a key role in the cycle of sediments that settle to the bottom. But, besides xenophiophores, what else is there? It is also speculated that there must be other microorganisms inhabiting the bed, although it is very difficult to obtain samples of these organisms, since they do not resist such sudden changes in conditions. But let’s go up a bit.
Eight kilometers under the sea
In September 2018, in the Peru-Chile trench, the deepest species of fish found to date were found. These animals have a characteristic “gelatinous” tissue, not very consistent and that “melts” when the pressure and temperature are not those of the marine fossa they inhabit.
Although this belongs to other graves, the truth is that it would serve us well to illustrate some of the surprising species that can appear deep in the Marianas. However, unlike in other sea chasms, this one seems spectacularly lonely.
As reported by Cameron, and confirmed by Vescovo, unlike in other deep dives, bioturbations are not observed in the Mariana Trench. These consist of modifications of the terrain by animals, such as worms or holothurians. Above 7,000 or 8,000 meters, in this pit, the largest are amphipods, small crustaceans similar to prawns.
Some species of cephalopods probably reach these depths, especially some so-called giant squids, although we do not know for sure, since the conditions here are extreme. If we continue climbing, little by little, the barren desert is inhabited by different beings, each one more strange. From shiny cnidarians (jellyfish and hydras), to toothy, blind fish, to sucker squid, long-legged crustaceans and quirky sea cucumbers …
The cast between the hadal and the abyssal zone, between 4,000 and 6,000 meters, resembles the craziest ideas we have about aliens. Some of the most terrifying monsters in our cultural heritage come from here. If we keep going up, the sea is becoming more and more populated. From 700 meters, where the light begins to arrive (although it is barely seen), life is rich, especially when approaching the continental slope, although we will not see this in the Mariana Trench, of course.
We have been more times on the Moon than on the bottom of the sea
Specifically, we have been eight more times . The surface of the Moon has been stepped on by a dozen more humans than have even been able to get close to the bottom of the pit. For what reason? Both outer space and the depths of the sea are completely inhospitable places for humans. There are direct and ominous dangers, although each of these environments has its own in particular, simplifying it a lot.
In the case of the bottom of the Mariana Trench, the most destructive danger is pressure. In the case of space, it could be radiation. In both cases, there are a multitude of factors that can be fatal. But let’s continue the comparison, why have we reached the Moon more times than the limit of the Mariana Trench (which we have not reached)?
Thanks to the Earth’s magnetosphere, missions to the Moon have been completed with some success, avoiding an amount of radiation that could have been lethal to astronauts. But the more than 1,000 atmospheres of pressure to which the bathyscaphs are subjected when going down is unbeatable. Putting a “bubble” with people inside, protected from this action, being able to breathe and not having any kind of accident … is more difficult.
That is not to say that it cannot be done, as we have already shown, and as was proven with incredible success in the last Vescovo expedition, aboard the DSV limiting factor. This vehicle is reinforced in aluminum, has its own sonar and a complex propulsion and descent system, as well as cameras and analysis instruments. But its greatest achievement is the incredible resistance it shows, capable of withstanding, at least in the laboratory, more than 12,000 atmospheres.
But, in addition to the technical section, there is another answer to the question. If we have not arrived more times, it is probably because the seabed has never been as attractive as space or the Moon. We have never experienced a “race” like space. Perhaps because we do not know what is under the sea. It is estimated that only between 1% and 2% have been explored. Fortunately, a little of that percentage is in the deepest part of the sea.
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