What happens to a person at great sea depths?


In the era of space exploration, our options are limited. The human body, alas, is too vulnerable to travel around the solar system, so we are being replaced by robotic vehicles – real pioneers. But what if, instead of distant planets, we turn our attention to our own? Are there places on Earth that no human has set foot on?

Take, for example, the bottom of the ocean: unfortunately, freely swimming at great depths for members of the Homo sapiens species is like flying to Mars. Our bodies are incredibly fragile, and the pressure of water at great depths can kill even the most experienced scuba diver.

Lack of breathable oxygen and unimaginable cold are just some of the problems that can be encountered when exploring the Mariana Trench. Strong water pressure poses a threat to life, because it is much less than the ambient pressure. As a result, once at great depths, your lungs will not be strong enough to withstand the high pressure.

And the deeper you go down, the less chance of survival. As you dive, your lungs will begin to completely collapse, so that instant death will be guaranteed to you. But can something be done about it? What are the limits of our survival? And what happens to the body when we try to cross this dangerous boundary?

It just so happened that there are incredibly few places for comfortable living and prosperity of mankind. So if you somehow get stuck in the middle of the ocean abyss, the chances of returning to land will be zero, the less chance of survival.

Secrets of the World Ocean

Most of the Earth is a huge body of water. Water covers 71% of our planet’s surface. Geographically, this volume is divided into separate regions, and the boundaries between them have changed more than once over time for a number of historical, cultural and scientific reasons.

That is why today there are four named oceans: Atlantic, Pacific, Indian and Arctic . However, some countries recognize another ocean – the fifth or Southern (Antarctic). Unlike the Pacific, Atlantic and Indian Oceans, the Southern Ocean is practically new and has received much less fame.

Its borders were marked by the International Hydrographic Organization back in 2000, but not all world powers agree with the innovation, so the status of the Southern Ocean is now in question.

Historically, many maps and textbooks have presented the classical model of four oceans. The first three – Pacific, Atlantic and Indian – are the main ones, while the Arctic Ocean occupies a less prominent place in our minds.

A possible reason is its small size and location on the periphery of the map. In addition, the Arctic Ocean is partially covered with ice. At the same time, all five designated oceans are part of a single whole. Boundaries, as is often the case, only exist in our heads. But how deep is the ocean?

The world ocean is the main part of the hydrosphere, a continuous, but not continuous water shell of the Earth, surrounding the continents and islands.

Researchers estimate the maximum depth of the World Ocean at 11,022 meters. And by analogy with the study of Mars and other bodies of the solar system, the ocean floor is mastered by robots instead of us, or rather deep-sea robotic vehicles.

With their help, scientists keep records of biological resources: since the device moves silently, it does not scare away fish and other inhabitants of the underwater world. But will scientific and technological progress help sink into the Mariana Trench?

Water pressure at great depths

Before we make an imaginary journey deep into the ocean, let’s deal with pressure. Firstly, we are always under a certain pressure, we just do not notice it. Secondly, our internal pressure is usually equal to the air pressure, that is, the weight of the atmosphere pressing against us.

This is why we experience discomfort whenever we move away from land and sea levels in an airplane. During climbing, our internal pressure does not equal the pressure of the environment, as a result of which our ears are “laid”. The same thing happens when we dive too deep underwater. Needless to say, deep-sea diving without an airtight suit is life-threatening.

At a depth of 11 km, the pressure literally flattens all life

But the suit is not a panacea. With each dive of ten and a half meters, the weight of the water above us will increase. And if you continue to “descent,” the pressure of the water will be too great for the muscles to work and, in the first place, it will make breathing extremely difficult. Then the lung tissue begins to contract, leaving only a small supply of air.

The next stage is called the “dive response” during which blood rushes to the heart and brain. This additional inflow dilates the blood vessels in the chest, as if balancing the water pressure.

As for the deepest dives, their characteristic difference is the reduction in heart rate to 14 beats per minute; for reference, this is about a third of the norm for a person who is in a coma. Scientists are not sure why divers do not lose consciousness at significant depths.

Perhaps the instinct of self-preservation allows them to do some pretty crazy and life-threatening things. This is certainly convenient, but only for a short period of time. In general, the depth limit subject to man has not yet been determined. Today, the maximum depth for diving among professional divers barely exceeds 120 meters.

The air pressure inside the body balances the pressure outside. Water, however, is much heavier than air.

It turns out that the only way to test how deep into the ocean we can look is to test it on a living person. But such studies can hardly be considered humane and in any way effective. In addition, scientists know everything that happens to scuba divers – death will occur either from pulmonary bleeding, or from loss of consciousness and redistribution of blood flow. More to the point, professional divers often spit blood on their way to the surface and are generally close to their own body’s limits.

What lives at the bottom of the ocean?

As you can see, deep sea diving is an extreme activity. Fortunately, the development of technology allows us to study the ocean and sea depths. Take, for example, the Mariana Trench, which is the deepest point on the planet.

Located in the Western Pacific Ocean east of the Philippines, the Mariana Trench is a crescent-shaped scar in the earth’s crust. Its length is more than 2550 kilometers, its width reaches 69 km, and the distance between the surface of the ocean and the deepest point of the depression is 11 kilometers.

If Everest were thrown into the Mariana Trench, its peak would still be more than a mile and a half under water. The Mariana Trench is part of a global network of deep trenches that cut through the ocean floor. They are formed when two tectonic plates collide, causing one of the plates to sink under the other into the Earth’s mantle.

The depths of the Mariana Trench were first explored in 1875 by the British ship HMS Challenger as part of the first global oceanographic cruise. The Challenger scientists recorded a depth of about eight kilometers, and in 1951 the British ship HMS Challenger II determined a depth of almost 11 kilometers.

Due to its extreme depth, the Mariana Trench is shrouded in perpetual darkness, with temperatures only a few degrees above freezing. The water pressure at the bottom of the trench is about a thousand times higher than standard atmospheric pressure at sea level.

The deepest point on the planet is the Mariana Trench

Today, scientists have absolutely no doubt that life can exist in the Mariana Trench. Well, or organisms, which we can call it that. The pressure there is so great that all vertebrates literally dissolve, which means there are no fish or their bones.

However, mistakes are inherent in scientists, and the ability of living organisms to survive in extreme conditions is the merit of adaptation. So does anything live at the bottom of the Mariana Trench? For example, microbes that reproduce oxygen without sunlight. There is no single answer to this question today, so all hope is for further research.

In addition, over the past few years, many exotic organisms have been discovered, including strange translucent animals – holothurians, which are relatives of starfish and urchins. Just imagine how many species unknown to science can live in the deepest, darkest and coldest cavity of the planet. Scientists are especially interested in local microorganisms, which can supposedly lead to breakthroughs in biomedicine and biotechnology.

The Mariana Trench is inhabited by numerous species of invertebrates.

The microscopic inhabitants of the Mariana Trench may also shed light on the origin of life on Earth. Some researchers, such as Patricia Fryer of the University of Hawaii and her colleagues, have suggested that mud volcanoes located near ocean trenches could provide suitable conditions for the first life forms on our planet.

Life on the bottom of the Mariana Trench may include the Mariana snail, supergiant amphipods (shellless crustaceans), and sea cucumbers. In addition, studying rocks from ocean trenches can lead to a better understanding of the earthquakes and devastating tsunamis seen throughout the Pacific.

Pollution of the oceans

It may seem surprising, but plastic and other waste pollution has reached the Mariana Trench. According to National Geographic, not so long ago, researchers discovered a plastic bag and candy wrappers inside the deepest point on the planet.

And earlier studies have also found crustaceans to have elevated concentrations of chemicals banned in the 1970s, along with microplastics in their stomachs. Rounding out the list are traces of carbon-14 from nuclear bomb tests. It turns out that man’s ability to pollute the environment surpasses all others. It’s a shame.

Meet the new inhabitant of the Mariana Trench – a plastic bag.

The fact that we have found such extraordinary levels of these pollutants in one of the most remote and inaccessible habitats on Earth is truly indicative of the long-term devastating impact that humanity is having on the planet, the researchers note.

The Mariana Trench is also not immune to plastic pollution, which is slowly but surely penetrating the oceans. A 2018 paper published in the journal Geochemical Perspectives found that microplastics are extremely common in the deepest waters of the Mariana Trench.

Plastic literally seeps through the ocean and concentrates at its deepest points. Unfortunately, rapid climate change has a negative impact on the oceans, as it literally makes it lose its memory.