Marine biologists like to carry plastic foam products, such as cups, when studying the seabed. They usually engrave diaries, various patterns or print the name of the expedition team on the quilt and then put them on. the submersible.
As the diving depth of the submersible increases, seawater pressure will gradually compress these cups. Eventually these cups will be compressed into a small part of the original, but the density will be higher than before. .
Some people like to collect these cups compressed by water from the depths of the sea. Through these cups, we can also directly feel the pressure exerted on the seabed.
Since seawater pressure can compress foam cups, why can deep-sea fish live here?
Deep water pressureWhere the depth of sea waterexceeds 200 meters, we speak of deep sea. With different depths, it is divided into: middle zone, deep zone, abyssal zone and ultra-abyssal zone (sea water depth exceeds 6,000 meters). Sea water pressure will increase as sea depth increases. For every 10 meters of depth of sea water, the pressure will increase by 1 atmosphere. At 4,000 meters deep, an area the size of a fingernail must support the weight of an elephant.
Generally speaking, the deeper the seawater, the less energy it has, so the deeper the seawater, the fewer organisms, and the ultra-abyssal zone has the fewest organisms. However, the University of Aberdeen in the United Kingdom discovered a kind of lionfish in the ultra-deep abyssal zone at a depth of 7,700 meters. Although the energy here is scarce and the pressure is high, the lionfish lives here very comfortably.
The lionfishhe ultra-abyssal zone is considered the vertebrate with the deepest known habitat in the region. Scientists have discovered through research and anatomy that the body mechanism of lionfish has undergone great changes in order to. adapt to the super pressure of deep sea changes.
First of all, their skin is almost transparent, and we can directly see the inside of their body from their appearance. The reason they are transparent is that their skin is very thin, only the thickness of a layer of membrane, which can maintain the balance of pressures inside and outside the fish.
We can think of a fish as a balloon. If the pressure outside the balloon is too high and the pressure inside the balloon is too low, the balloon will be compressed. If the pressure inside the balloon is high and the pressure outside is low, the balloon will expand and burstra. Only when the pressure inside and outside the fish is constant can the fish survive.
The same goes for deep-sea lionfish. Their skin tissues will attempt to ensure that the pressure in their body is consistent with the external pressure, so that they do not feel pressure changes.
Also, although they have bones, their bones are very thin and bend easily, and their muscles are also very flexible, all to reduce pressure in the body and in the environment . .
Why can deep-sea fish adapt to the deep-sea environment?Although most organisms are accustomed to keeping the pressure inside and outside the body constant, the environment on the sea floor is different. You should know that the pressure inside and outside the cup is also the same, but. they are at high altitude.Theyhave also compressed in a pressurized environment. It stands to reason that the fish should be the same, but why aren't they compressed like cups?
In the late 1970s, a group of scientists began to study why deep-sea fish can withstand the enormous pressure on the seafloor. They discovered that there is a substance called lactate dehydrogenase (LDH) in deep-sea fish. However, the LDH of fish living in the diving layer cannot adapt to the deep-sea environment. LDH found in deep-sea fish cannot adapt to the deep-sea environment. LDH substances can adapt to deep water pressure.
In addition, there is a molecule called trimethylamine oxide (TMAO) in deep-sea fish, which can effectively prevent protein distortion by seawater pressure, resulting inis equivalent to the deformation of proteins in living organisms. Proteins play a stabilizing role.
British scientists detected the content of trimethylamine oxide in deep-sea lionfish and found that the survival limit of this fish is 8,200 meters under the sea.
Although deep-sea lionfish can survive in deep water, their bodies can no longer adapt to the pressure of the sea surface. If we catch them on land, they will burst like an inflated balloon . This is because the pressure inside their body is higher, while the pressure outside is lower.
SummaryThe deep water environment is very harsh and only a few creatures can survive there. However, what shocked scientists was that in the Mariana Trench, the deepest trench in the known world, scientists found themselves. the 10,000 meter chasm. ArtefaHuman objects were discovered on the seabed: plastic bags. In other words, plastic products made by humans reached the abyss before humans did. This shows that due to the existence of humans, the pure land of the deep sea has also been polluted and damaged.
The key to knowing whether it will be crushed lies in the balance of pressures.
Crushing involves deforming the object so that it occupies a smaller space. The strength of the metal is generally relatively high. Although it is not easy to deform, it is not a problem under high pressure. Substances such as liquids and solids, unlike gases, are difficult to compress although they can become deformed.
In seawater, metal objects that can be crushed are usually hollow or closed, such as submarines and unopened Coke bottles, because this can create a pressure difference. THEChinese manned submersible Jiaolong once dived to a depth of 7 kilometers. Although the strength of the cabin is extremely high, it has also suffered slight deformation. As there are people inside the cabin, the pressure is almost the same as that of the ground. As a result, the pressure difference between the inside and outside of the submarine is very large.
In other words, to flatten an object, the external pressure must be greater than the internal pressure. Likewise, if the internal pressure is greater than the external pressure, expansion or even explosion will occur. This is why an empty can is easier to crush with your hands, but a full Coca-Cola can is not.
If it is a solid metallic object, or a metallic object in the open state, it will not undergo significant deformation even if it sinks to the seabed the most. deepest in the world. Humans have roamed the oceans sinces hundreds of years and many ships sunk in the deep sea, such as the Titanic.The wreck of the USS K lies on the sea floor, 3,750 meters underwater. However, because the interior of these sunken ships is filled with seawater, the overall structure does not deform under the enormous pressure of seawater.
As shown in the picture below, the sunken ship on the seabed still retains its original appearance.
Deep sea and deep water fish
Water pressure in deep water is indeed very high. For every 10 meters of ocean depth, the pressure increases by an atmosphere. At the same depth, the pressure in all directions is the same.
How strong is atmospheric pressure? I think many people who have been to college know that there are many examples of the use of air pressure in life. The pressure of a standard atmosphere equatedis the pressure produced by a column of water 10.339 meters high or a column of mercury 76 centimeters high.
Three thirds of the earth is divided into seven parts of the sea. There are 4 oceans on earth: the Pacific Ocean, the Indian Ocean, the Atlantic Ocean and the Arctic Ocean. is 3,800 meters. The deepest place is located in the Mariana Trench near the Philippines, which has a depth of 11,000 meters, the water pressure there is 1,100 times higher than standard atmospheric pressure. The deep sea is internationally defined as the ocean area less than 200 meters above the sea surface. In the depths of the sea, in addition to high water pressure and high salinity , the temperature is generally low and it is dark.
What will happen as water depth increases?
In recent years, with the maturity of large-scale exploration technologyseabed, scientists have gained a deeper understanding of the seabed. In the past, marine life gradually declined as water depth increased. Scientists have discovered that this is not absolute. In some specific environments, the situation may also be abnormal. For example, the number of organisms living near deep-sea hot springs is very abundant. The capacity of living beings to survive is much greater than we imagine.
The animal currently known to live in the deepest part of the ocean is the short-legged Gammarus, and scientific researchers have found traces of it at the bottom of the Mariana Trench.
The image above shows the short-legged Gammarus lobata.
The most typical creature of the ocean is the fish. Currently, scientists have discovered fish at a depth of 8 kilometers. The fishdeep seas are smaller, but have oversized eyes and even have "lighting equipment". However, the eyes of some fish have also degenerated. Some body parts of some fish are still translucent and appear very random. When I first see their strange shapes, I feel like I've discovered alien life.
The image above shows a strange fish in the deep sea. Does this look strange?
In addition to fish, there are also invertebrates such as squid, octopus and shrimp, as well as a large number of plankton and microorganisms living in the deep sea.
Why are deep sea fish okay?
Without equipment, the human diving limit is generally around 100 meters, which is the maximum water depth that humans can physiologically withstand. SIf the pressure is too high, the body will not be able to handle it. Especially if the lungs are compressed, it will make breathing difficult and ultimately cause death from suffocation.
In addition to high pressures, it is also difficult for humans to adapt to low pressure environments. Toward the Qinghai-Tibet high altitude of more than 4,000 meters, it turns out that many people feel unwell because the air there is more thinner and contains less oxygen, which can easily lead to hypoxia. Additionally, low air pressure is also a significant cause of discomfort in the human body. Human beings cannot survive in space. One reason is that space is a vacuum and has no atmospheric pressure.
These deep-sea creatures do not have steel bodies. The reason they can live in such a high water pressure environment is because the pressure in these creatures is equivalent to the pressure of sea water outside. and there is no greater pressure, so the body will not be crushed and can survive.
The image above shows a deep-sea animal with a soft, transparent body and a high water content in its body.
Having lived in such deep seas for a long time, the physiological characteristics of these deep-sea fish are very different from those of shallow-water fish in some respects.
In waters thousands of meters deep, the bodies of these fish are very soft, and there is a lot of body fluid in their bodies. The main component of these bodily fluids is water. Because water is difficult to compress, coupled with special cellular and tissue structures, these creatures can withstand the pressure of the deep sea. Additionally, their flexible body structure allows them to remain intact under the presion of sea water at high pressure. Deep-sea fish do not have fish bodies as large as shallow-sea fish, and some fish do not even have fish bodies. The low gas content in the body can also reduce the pressure difference, so that the body and the sea water can maintain a pressure balance as much as possible.
Many living things in nature have adapted their body structures to live in a specific pressure environment for a long time. If the pressure is too high or too low, they will become uncomfortable or even die. If deep-sea fish are released into shallow seas, even if their bodies do not explode, they will die due to excessive pressure of bodily fluids.
There are also expert divers in the wild, such as sperm whales, who can live on the surface and dive into deep waters of pseveral thousand meters. Whales are mammals that breathe through their lungs. They need to inhale a large amount of air from the sea surface before diving. The reason why they can withstand the high pressure of the deep sea is mainly because their body structure is relatively strong and strong. their lungs can withstand higher pressure.