Every diver knows: when a colleague underwater suddenly starts behaving aggressively cheerfully, it means that he is in big trouble. He begins to claim that n front of his eyes there is also a flame burning, nitrogen anesthesia or, as others call it, deep drunkenness, has taken off.
I all the moment a diver dives. With each meter of depth, the pressure drops. For gases in the body, this only means that they will dissolve much faster and easier. Nitrogen, when it has the most, penetrates from the body fluids into the blood and is released in the form of bubbles, very similar to what happens when a bottle of champagne is opened. The trouble is that the consequences are far from similar: with decompression, because that's what it is about, there are unbearable pains in the joint where bubbles press on nerve endings, capillaries in the lungs become clogged, the diver's movements slow down and he eventually cramps, falls into unconsciousness. If he isn't helped in time, he will die due to the cessation of breathing and the work of the bloodstream.
Seals that dive to great depths and abruptly emerge to breathe air don't experience any of this. Why?
Everything that was know about this phenomenon until recently was known thanks to anatomical research and experiments in decompression chambers in which seals were subjected to forced "simulated" diving. The discovery was made in natural environment of the seal, in Antarctica, under the ice of the McMurdo Sea.
The experiment was performed by scientists from the University of Dusseldorf. An opening was made in a predetermined place in the ice. "Backpacks" were attached to four experimental seals, in which there was tiny pressure-resistant pump that was inserted into the arterial system of the animal. The pumps worked under the supervision of a computer programmed to take blood samples and at certain intervals and to record the pulse, swimming speed, and blood temperature at the same time. As soon as the seal surfaced, the collected data was entered into a computer on the surface.
The hole in the ice was six kilometers from the nearest crack, so that the seals, in order to breathe the air, were forced to return to the place of departure. Thanks to that, the scientists were able to immediately examine the blood samples taken at depths and measure the amount of nitrogen in them.
In this way, the amount of nitrogen in the seal's blood was measured to a depth of 230 meters. The finding was as follows: the pressure of nitrogen in the blood reaches its peak at depths of 30-70 meters, and then sharply decreases and continues to decrease throughout the descent. Low pressure is maintained even during ascent.
That is how the obtained data read, explanation for them still needed to be found. Apparently, it partly lies in the fact that the seal, before diving, exhales air, thus limiting the amount of nitrogen in the lungs that the bloodstream can later absorb. However, this doesn't fully explain phenomenon, because the researchers determined that the highest pressure of nitrogen in the blood is only 25 percent of the average lung capacity during diving.
Apparently, the alveoli also play a big role in reducing the amount of nitrogen in the blood, because it has been shown that at a depth of 28 meters, these air-filled bubbles in the lungs of the seal through which the gas exchange takes place disintegrate. In this way, the seals successfully prevent the absorption of nitrogen that has remained in the lungs. It is then pushed into the parts of the respiratory organs where there is no gas exchange.
The presence of hemoglobin could explain the fact that then the solubility of nitrogen in the blood increases by 8 to 10 percent. Judging by this, it is possible that if some other tissues, such as, for example, muscles and adipose tissue, are filled with blood , they also use the seal to distribute nitrogen, reducing their presence in the blood to safe limit when emerging.
In a word, nature has done to ensure that the seals at the depth never turn their heads. It remain for a men, based on what they learned from them, to overcome that danger themselves.
Literature and images: Politica's Entertainer, number 3581
Nature is amazing. Although despite all the research, I would dare to dive so deep. Definitely a great and instructive article for divers, and those who have only a small fear of diving.