Why the seas and oceans do not dry up. Can the sea dry up? What will happen to the earth

Why is the sea salty and where does the salt come from? This is a question that has interested people for a long time. There is even a folk tale about this.

As folklore explains

Whose legend is this, and who exactly invented it, is no longer known. But among the peoples of Norway and the Philippines, it is very similar, and the essence of the question of why the sea is salty, the tale conveys as follows.

There were two brothers - one rich, and the other, as usual, poor. And no, to go and earn bread for his family - the poor goes for alms to the stingy rich brother. Having received a half-dried ham as a “gift”, the poor, in the course of some events, falls into the hands of evil spirits and exchanges this very ham for a stone millstone, modestly standing outside the door. And the millstone is not simple, but magical, and can grind everything that the soul pleases. Naturally, the poor man could not live quietly, in abundance, and not talk about his miracle find. In one version, he immediately built a palace for himself one day, in another, he threw a feast for the whole world. Since everyone around him knew that just yesterday he lived in poverty, those around him began to ask questions about where and why. The poor man did not consider it necessary to hide the fact that he had a magic millstone, and therefore many hunters appeared to steal it. The last such person was a salt merchant. Having stolen the millstones, he did not ask him to grind money, gold, overseas delicacies, because having such a “device” it was possible not to engage in the salt trade. He asked to grind salt for him so that he would not have to swim behind her across the seas and oceans. A miracle millstone started up, and it ground so much salt for it that it sank the ship of the unfortunate merchant, and the millstone fell to the bottom of the sea, continuing to grind salt. This is how people explained why the sea is salty.

Scientific explanations of the fact

Rivers are the main source of salts in the seas and oceans.

Yes, those rivers that are considered fresh (more correctly, less salty, because only distillate is fresh, that is, devoid of salt impurities), in which the salt value does not exceed one ppm, make the seas salty. This explanation can be found in Edmund Halley, a man known for the comet named after him. In addition to space, he studied more mundane issues, and it was he who first put forward this theory. Rivers constantly bring a huge amount of water, along with small impurities of salts, into the depths of the sea. There, water evaporates, but salts remain. Perhaps earlier, many hundreds of thousands of years ago, the ocean waters were very different. But they add another factor that can explain why the seas and oceans are salty - volcanic eruptions.

Chemicals from volcanoes that bring salt to the sea

At a time when the earth's crust was in a state of constant formation, there were frequent ejections of magma with an incredible amount of various elements to the surface - both on land and under water. Gases, indispensable companions of eruptions, mixing with moisture, turned into acids. And those, in turn, reacted with the alkali of the soil, forming salts.

This process is happening now, because seismological activity is much lower than it was millions of years ago, but still present.

In principle, the rest of the facts explaining why the water in the sea is salty have already been studied: salts enter the seas from the soil by means of movement by precipitation and winds. Moreover, in each open reservoir, the chemical composition of the main terrestrial liquid is individual. When asked why the sea is salty, Wikipedia answers in the same way, only emphasizing the harm of sea water for the human body as drinking water, and the benefits when taking baths, inhaling and the like. No wonder sea salt is so popular, which is even added to food instead of table salt.

The uniqueness of the mineral composition

We have already mentioned that the mineral composition is unique in each reservoir. Why the sea is salty and how much it is, decides the intensity of evaporation, that is, the temperature of the wind on the reservoir, the number of rivers that flow into the reservoir, the richness of flora and fauna. So, everyone knows what the Dead Sea is, and why it is called that.

Let's start with the fact that it is incorrect to call this body of water a sea. It is a lake because it has no connection with the ocean. They called him dead because of the huge proportion of salts - 340 grams per liter of water. For this reason, no fish is able to survive in the reservoir. But as a hospital, the Dead Sea is very, very popular.

Which sea is still the most salty?

But the right to be called the most salty belongs to the Red Sea.

There are 41 grams of salts in a liter of water. Why is the Red Sea so salty? Firstly, its waters are replenished only by precipitation and the Gulf of Aden. The second is also salty. Secondly, the evaporation of water here is twenty times higher than its replenishment, which is facilitated by the location in the tropical zone. If it were a little further south, closer to the equator, and the amount of precipitation typical for this zone would drastically change its content. Due to its location (and the Red Sea is located between Africa and the Arabian Peninsula), it is also the warmest sea among all available on planet Earth. Its average temperature is 34 degrees Celsius. The whole system of possible climatic and geographical factors has made the sea what it is now. And this applies to any body of salt water.

The Black Sea is one of the unique compositions

For the same reasons, one can single out the Black Sea, whose composition is also peculiar.

Its salt content is 17 ppm, and these are not quite suitable indicators for marine inhabitants. If the fauna of the Red Sea strikes any visitor with its variety of colors and forms of life, then do not expect this from the Black Sea. Most of the "settlers" of the seas do not tolerate water with less than 20 ppm salts, therefore the diversity of life is somewhat reduced. But it contains many useful substances that contribute to the active development of unicellular and multicellular algae. Why is the Black Sea half as salty as the ocean? This is primarily due to the fact that the size of the territory from which river water flows into it exceeds the area of the sea itself by five times. At the same time, the Black Sea is very closed - only a thin strait connects it with the Mediterranean, but otherwise it is surrounded by land. Salt concentration cannot become very high due to intensive desalination by river waters - the first and most important factor.

Conclusion: we see a complex system

So why is the sea water salty? It depends on many factors - river waters and their saturation with substances, winds, volcanoes, precipitation, evaporation intensity, and this, in turn, affects the level and diversity of living organisms in it, both flora and fauna. This is a huge system with a large number of parameters that ultimately make up an individual picture.

How quickly will the oceans dry up if in the Challenger Abyss - the deepest point in the world's oceans - there is a portal with a diameter of 20 meters leading straight into space? And what will happen to the Earth in this case?

Let me start by saying the following:

According to my rough estimates, if an aircraft carrier sank there and blocked the drain, then the pressure would be more than enough to crush it and suck it through the portal. Cool.

But how far does this portal lead? If we place it close to the Earth, then the water will simply fall back onto the Earth. Falling, the water heats up and turns into steam, then condenses and returns to the ocean as precipitation. In addition, the energy released into the atmosphere due to these processes will seriously affect our climate, not to mention the impact of huge clouds of vapor hanging at high altitude.

So let's place the ocean shipping portal further away - say, on Mars. (In fact, I vote to place it directly above the Curiosity rover - this way we will have irrefutable evidence of the existence of water on the surface of Mars.)

What will happen to the Earth?

Right away, nothing serious. It will take hundreds of thousands of years to dry up the oceans.

Even though the opening is wider than a basketball court and the water moves at incredible speeds, the sheer size of the oceans makes up for it. At first, the water level will drop by less than a centimeter a day.

And no cool whirlpool forms on the surface - the portal is too small, and the ocean is too big. (For the same reason, the tub does not swirl when it is more than half full.)

But let's assume that we speed up the drain by opening more drains. (Remember to clean the whale filter every few days, then the water level will drop faster.)

Let's see how the map changes.

This is how it looked originally:

And this is what it looks like after lowering the water level by 50 meters:

The similarities are strong, but there are also some differences: Sri Lanka, New Guinea, the UK, Java, and Borneo now have overland links with their neighbors.

And now, after 2,000 years of constant attempts to drive the sea back, the Netherlands is finally up and dry. No one is obsessed with the constant threat of flooding anymore; now the Dutch can think about external expansion. And they immediately proceed to it, appropriating new lands.

When the sea level reaches (minus) 100 meters, a huge new island will open up near Nova Scotia - the former Great Newfoundland Bank.

You may notice something unusual: not all seas dry up. For example, the Black Sea will decrease quite a bit, and then it will completely stop drying.

This is because these areas are no longer connected to the ocean. As sea levels fall, some bodies of water will stop drying up. Depending on the details of the seabed topography, undercurrents can cut deep channels that allow water to flow out. But most of the seas will eventually be surrounded by land and stop drying up.

At 200 meters the map starts to look weird. New islands appear. Indonesia is like a big blob. The Netherlands now controls most of Europe.

Japan becomes an isthmus connecting the Korean Peninsula with Russia. New Zealand gets new islands. The Netherlands is expanding to the north.

New Zealand is growing very fast. The Arctic Ocean is cut off from the portal by land, and the water level in it stops falling. The Netherlands penetrates into North America through a new isthmus.

The sea level dropped by two kilometers. New islands appear here and there. The Caribbean Sea and the Gulf of Mexico are no longer connected to the Atlantic Ocean. I don't even know what New Zealand is doing.

At a level of 3 kilometers, many peaks of ocean ridges - the longest mountain systems on Earth - break out to the surface. Huge swaths of new, uneven land protrude from the water.

By this point, most of the major oceans will have separated and stopped shrinking. The exact location and size of the various inland seas is difficult to determine, and only rough estimates can be made.

This is what the map will look like when draining is over. There will be an unexpected amount of water left, although most of it is now contained in shallow seas, and some depressions will be up to four to five kilometers deep.

Sucking out half of the oceans will lead to the most serious, poorly predictable changes in climate and ecosystems. This will almost certainly lead to the destruction of the biosphere and mass extinction at all levels, if not worse.

But it is possible - though unlikely - that people can survive. And if we manage to survive, then we will have to count on the following:

How people discovered their land Tomilin Anatoly Nikolaevich

Can the sea dry up?

The Mediterranean Sea is located between Europe, Asia Minor and North Africa and is surrounded on all sides by land. Two narrow straits - the Gibraltar and the Dardanelles - connect it with the rest of the oceans - with the North Atlantic and the Sea of Marmara. Even people themselves dug the Suez Canal, which leads through the Red Sea to the Indian Ocean.

According to the bottom topography, the Mediterranean Sea consists of two basins connected by shallow waters surrounding the island of Sicily.

When we were at school, in history lessons, talking about Ancient Greece, the teacher mentioned the seas of the eastern Mediterranean - the Adriatic Sea, the Ionian, Aegean and Marmara, located between the Dardanelles and the Bosphorus. We were familiar with the names of the Ligurian and Tyrrhenian seas, the Bolearic and Alboran seas ... However, their boundaries are set arbitrarily and they all enter the Mediterranean basin.

Approximately in the 60s of our century, geophysicists found at the bottom of the Mediterranean Sea under a loose sedimentary layer a dense layer that reflects sound waves well. It was called "reflector M". What was the surprise of scientists when, having drilled the bottom to this “reflector”, they discovered that it consists of such sediments that can be formed only with the complete evaporation of water.

Was there really a time when the Mediterranean dried up? Apparently, yes ... For some geological reasons, the Strait of Gibraltar could close. And then the sun would need only about a thousand years to dry up the sea and turn it into a huge basin with small drying salt lakes.

Then the Strait of Gibraltar reopened. Such a rapid flow of water from the Atlantic burst into the formed passage that it is difficult to imagine it. And yet, it took at least two thousand years for the dried-up depression to fill up again and again turn into a sea.

But now I will tell you about an even more amazing discovery. In a core column taken from a drilled well, geologists counted 11 layers with ordinary deep ocean sediments. And this means that during its existence the Mediterranean Sea dried up 11 times!..

When could it be? All these catastrophic events took place about five and a half - six million years ago. Scientists believe that it was then that strong earthquakes occurred in that area. The land, and hence the seabed, rose up and down. The drying up of the sea changed the climate in Europe. Paleontologists confirm that at about the same time, luxurious forests in the surrounding areas were replaced by steppes.

But where could such a huge amount of evaporated water go?

First into the clouds, and then out of the clouds, in the form of rain and snow, again into the ocean. And again, scientists confirm: indeed, in those days, the waters of the oceans rose more than once. This could be due to the addition of evaporated water from the Mediterranean Sea to them ...

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Water forms the water shell of our planet - the hydrosphere (from the Greek words "hydro" - water, "sphere" - a ball).

¾ of the surface of the globe is water, and ¼ is land. The hydrosphere will include three main parts: the oceans, land waters and water in the atmosphere.

The oceans account for over 96% of our planet. Continents and islands divide it into separate oceans: Pacific, Atlantic, Indian and Arctic.

Land waters are rivers, lakes, swamps, glaciers and groundwater. The share of rivers, lakes and swamps is very small - only 0.02% of the volume of the hydrosphere.

Much more water is contained in glaciers - about 2% of the volume of the hydrosphere. Do not confuse them with the ice that forms when water freezes. Glaciers are formed from snow. They occur where there is more snow than it has time to melt. Gradually, the snow accumulates, compacts and turns into ice. Glaciers are located on the mainland Antarctica and Greenland, as well as on the tops of high mountains.

Groundwater makes up about 2% of the hydrosphere.

There is water in the atmosphere, it is there, in the form of water vapor, water droplets, ice crystals. Atmospheric moisture is only 1/1000 of the total water supply on Earth, but its role is enormous. It feeds rivers, lakes, glaciers, saturates the Earth with water. Without it, the water cycle on our planet would not be possible.

Hydrology is a science that studies natural waters, their interaction with the atmosphere and lithosphere, as well as the phenomena and processes occurring in them (evaporation, freezing, etc.).

The subject of hydrology is all types of waters of the hydrosphere in the oceans, seas, rivers, lakes, reservoirs, swamps, soil and groundwater.

Hydrology studies the water cycle in nature, analyzes the hydrosphere, evaluates and forecasts the state and rational use of water resources. Uses methods used in geography, physics and other sciences. Marine hydrology data are used in navigation and warfare by surface ships and submarines.

Hydrology is subdivided into oceanology, land hydrology and hydrogeology.

The importance of water for our planet, humans and living organisms

Scientists are absolutely right: there is no substance on Earth that is more important for us than ordinary water, and at the same time there is no other such substance, in the properties of which there would be as many contradictions and anomalies as in its properties.

Almost 3/4 of the surface of our planet is occupied by oceans and seas. Solid water - snow and ice - covers 20% of the land. The planet's climate depends on water. Geophysicists say that the Earth would have cooled down long ago and turned into a lifeless piece of stone, if not for water. She has a very high heat capacity. When heated, it absorbs heat; cooling down, gives it away. Terrestrial water both absorbs and returns a lot of heat and thus "levels" the climate. And those water molecules that are scattered in the atmosphere protect the Earth from cosmic cold - in clouds and in the form of vapors one cannot do without water - this is the most important substance on Earth.

There is more than enough water on Earth. But we must not forget that life on planet Earth, according to scientists, first appeared in water, and only then came to land. Organisms have maintained their dependence on water in the course of evolution for many millions of years. Water is the main "building material" of which their body consists. This can be easily verified by analyzing the numbers in the following table:

Table 1

Medusa 97-99%

Cucumbers, salad 95%

Tomatoes, carrots, mushrooms 90%

Pears, apples 85%

Potato 80%

Human 65-70%

The last number of this table indicates that a person weighing 70 kg contains 50 kg of water! But there is even more of it in the human fetus: in a three-day period - 97%, in a three-month period - 91%, in an eight-month period - 81%.

The problem of "water hunger" is the need to maintain a certain amount of water in the body, as there is a constant loss of moisture during various physiological processes. For a normal existence in a temperate climate, a person needs to receive about 3.5 liters of water per day with food and drink, in the desert this rate increases to at least 7.5 liters. Without food, a person can exist for about forty days, and without water, much less - 8 days. According to special medical experiments, with a loss of moisture in the amount of 6-8% of body weight, a person falls into a semi-conscious state, with a loss of 10%, hallucinations begin, with 12%, a person can no longer recover without special medical care, and with a loss of 20%, inevitable death.

Many animals adapt well to a lack of moisture. The most famous and striking example of this is the "ship of the desert", the camel. He can live for a very long time in a hot desert without drinking water. At the same time, without prejudice to its performance, it loses up to 30% of its original weight. So, in one of the special tests, a camel lost 100 kg out of 450 kg of its initial weight in 8 days of work under the scorching summer sun. And when they brought him to the water, he drank 103 liters and regained his weight. It has been established that a camel can get up to 40 liters of moisture by converting the fat accumulated in its hump. Desert animals such as jerboas and kangaroo rats do not use drinking water at all - they have enough moisture that they get from food and water that is formed in their body during the oxidation of their own fat, just like camels.

Even more water is consumed for their growth and development of plants. A head of cabbage “drinks” more than one liter of water per day, one tree, on average, more than 200 liters of water. Of course, this is a rather approximate figure - different tree species in different natural conditions consume very, very different amounts of moisture. So the saxaul growing in the desert spends the minimum amount of moisture, and the eucalyptus, which in some places is called the "pump tree", passes through itself a huge amount of water, and for this reason its plantations are used to drain swamps.

Three states of water.

The transition of water from one state to another

We are already familiar with some properties of water. Water is transparent, colorless, odorless and tasteless, flowing. Water can be liquid (in the seas, oceans, rivers, lakes), solid (in the form of snow and ice) or gaseous.

Ice is the solid state of water. A thick layer of ice has a bluish color, which is associated with the peculiarities of light refraction. The compressibility of ice is very low. Ice at normal pressure exists only at or below 0°C and is less dense than cold water. That is why icebergs float in water. At the same time, since the ratio of the densities of ice and water at 0 ° C is constant, ice always protrudes from the water by a certain part, namely by 1/9 of its volume.

Experience: Take an ice cube with a volume of 169 cm3. We lower it into the water and measure the height of the protruding part of the ice above the water. The height is 0.4cm, which is 17cm3. Therefore, it is 1/9 part.

Water that is in a gaseous state is called water vapour. When people talk about air humidity, they usually mean the amount of water vapor. If the air is described as "moist", it means that the air contains a large amount of water vapor.

How can water be transferred from one state to another? To answer this question, let's do an experiment.

Experiment: Let's take a lump of snow 19 grams, the temperature of the snow is -1 ° C, put it in a flask and heat it up. After 4 minutes, the snow will melt and water will form in the glass. Therefore, when heated, solid water turns into a liquid. Let's continue heating the water. It will boil in 1 minute. If you heat it for 11 minutes, then it will all evaporate. It will turn into water vapor. Water vapor is an invisible impurity.

The temperature at which it boils is called the boiling point. Typically, this temperature is 100°C. But boiling can occur at other temperatures as well. It depends on atmospheric pressure. Boiling water is used in everyday life, in various industries. It is also found in nature in the form of geysers.

Thus, when heated, water changes from a solid state to a liquid state, and then from a liquid state to a gaseous state.

When cooled, water changes from a liquid state to a solid state. We often observe this process in nature, when water bodies freeze in autumn. Ice is on top, it is lighter than water, its layer reliably protects the inhabitants of the reservoir from winter frosts.

If all the glaciers melted, then the water level on the Earth would rise by 64 m and about 1/8 of the land surface would be flooded with water.

Sea water, with its usual salinity of 35 ‰, freezes at a temperature of −1.91 ° C.

Processes: evaporation, transpiration, condensation

When heated and boiled, water turns into steam, this is evaporation. Evaporation is the process by which water changes from a liquid state to a gaseous state. Evaporation occurs at any temperature, but when boiling, water vapor is formed especially quickly. Puddles dry up after rain in both hot summer and cold autumn. But in the summer they dry out faster. Wind accelerates evaporation, so puddles dry out faster in windy weather. Water evaporates from the surface of the oceans, lakes, rivers, reservoirs.

Evaporates not only water, but also other liquids. Ice gradually evaporates as well. Therefore, water vapor rises above the glaciers. Linen dries in the cold.

Plants evaporate a significant amount of water from the land surface. Transpiration is the process of changing water from a liquid to a gaseous state during the respiration of living organisms. The fact that each plant evaporates water can be seen by doing a simple experiment.

Experience: Place a leaf of a houseplant peralgonia in a glass flask without cutting it off from the plant. Close the neck of the flask with cotton wool. After a while, water droplets will appear on the walls of the flask. Where did the water in the flask come from? The leaf evaporated her.

Evaporation of water from plant leaves is different from evaporation from the surface of a reservoir. In plants, this is a complex life process. Plants evaporate water through small holes in the leaf - stomata. The stomata of most plants are in the skin on the underside of the leaf. Periodically, opening and closing, they regulate the flow of air into the leaves. The number of stomata per 1 mm 2 leaves ranges from several hundred to a thousand. There are more than a million of them on one linden leaf, and several million on a cabbage leaf. The stomata are very small. The tip of a thin needle seems to be a giant compared to a small stomata. Despite their small size, more than 90% of the water absorbed by the plant evaporates through the stomata.

The larger the leaves, the more water they evaporate. Usually large leaves have plants of wet places. The homeland of our indoor plants with large leaves - begonias, ficus - tropical rainforests.

To determine how much water the plant evaporates, another experiment will help.

Experience: A shoot (stem with leaves) of tradescantia was placed in a vessel with water. A little vegetable oil was poured into a vessel on the surface of the water. The oil layer prevents evaporation from the water surface. Place a vessel with water on the scales and balance the scales with weights. In a day, the scales on which the vessel is located will rise. Rebalance the scale pans by placing several weights on the raised pan. Calculate how much water (in grams) the leaves of the cut shoot evaporated per day.

table 2

Experience results

The amount of water in the vessel

1 day of observation 158 gr 510 ml gr

Day 2 of observation 158 gr 10 ml

Day 3 of observation 157 gr 300 ml

Conclusion 1 g 210 ml g evaporated leaves of the cut shoot

One cabbage plant evaporates up to 1 liter of water per day, oak - 50 liters, birch - 60 liters, sunflower up to 100 liters of water.

In nature, another process is widespread - the transformation of water vapor into water. Try breathing on a mirror. Its surface will be covered with water droplets. Where did she come from? Experience gives the answer.

Experiment: If a small glass or metal plate is placed over boiling water, water droplets form on it. This water vapor turns into water, i.e., condensation occurs. In the same way, water vapor condenses when we breathe on a mirror.

It is easy to observe the condensation of water vapor if you hold a saucer over the spout of a kettle with boiling water.

The importance of the processes of evaporation, transpiration and condensation for nature and man

Evaporation is of great importance in human and animal life. Difficulty in evaporation can cause overheating of the body. Coming out of the water after swimming, even on a hot day, there is a coolness. This is because when the water evaporates, the temperature on the surface of the body decreases.

The sun strongly heats various objects: stones, sand, iron, etc. It also heats the leaves and stems of the plant. The evaporation of water on a sunny day cools the plants and protects them from overheating. At the same time, the temperature on the surface of the leaves decreases to the air temperature and below. That is why under the crown of trees, even in dry and hot weather, it is cool and easy to breathe. However, excessive strong evaporation causes wilting of plants, and sometimes their death. That is why plants have developed various adaptations to reduce evaporation. So the leaves of many plants of arid places are modified into thorns, for example, in cacti. Evaporation depends not only on air temperature, but also on other environmental conditions, such as the time of day. During the day, plants evaporate a relatively large amount of water, and at night very little. Therefore, in order for the flowers to retain their fresh look longer, they are cut in the evening. In the shade, plants evaporate less water than in the sun. With a strong and dry wind, evaporation occurs faster than in calm weather.

With the condensation of water vapor we meet in everyday life. On a summer evening or early morning, when the air gets colder, dew falls. This water vapor in the air, when cooled, settles on grass, leaves and other objects in the form of small droplets of water. Clouds also form as a result of the condensation of water vapor. Rising above the ground and water bodies into the upper, colder layers of air, this vapor forms clouds, consisting of tiny water droplets. If the air temperature is low enough, the water droplets freeze. Snow falls from such clouds, and sometimes hail.

All water on earth is in constant motion. Evaporating from the surface of the land, oceans, seas and other bodies of water, it replenishes atmospheric moisture in the form of vapors. Almost 90% of water vapor falls on the lowest 5-kilometer layer of the atmosphere. Most of this moisture comes from the surface of the World Ocean and the zone of humid equatorial forests.

As the temperature drops, the vapor condenses. Therefore, at an altitude where the air temperature drops, clouds form. The winds carry the clouds. And with them, atmospheric moisture from one area of the ocean to another, from the ocean areas to land areas. Falling out in the form of rain, snow or hail, atmospheric moisture, continuing its movement, feeds groundwater, rivers and lakes, forms glaciers, moistens the soil, is absorbed and then evaporated by plants. A forest, for example, evaporates 10 times more water than a body of water of the same area. Having fallen on land, the water partially evaporates again, replenishing the reserves of atmospheric moisture, and again falls in the form of precipitation to the earth.

The water that air currents bring from the ocean to land is returned by rivers to the ocean. This is how the eternal cycle of water in nature takes place. At the same time, it passes from one state to another, moves around the globe from one region to another.

What forces set in motion the huge masses of water that make up the planet's water shell, its hydrosphere?

The main force is solar heat. Under its influence, water evaporates, snow and glaciers melt, and a wind arises that carries water from one place to another. With a lack of heat, water condenses.

An important role is also played by gravity, under the influence of which raindrops fall, water flows from higher places to lower ones. Under the influence of gravity, water seeps deep into the earth, glaciers slide. The process of movement of water in nature, starting in the World Ocean and ending in it, is circular in nature and is called the water cycle in nature. Thanks to which the water on our planet does not dry out.

The water cycle in nature not only sets in motion the entire water shell of the Earth, but also connects all parts of the hydrosphere into a single whole, constantly replenishing water supplies in its various parts. However, the rate of replenishment of water reserves in different parts of the hydrosphere is not the same. Most often, there is a change in atmospheric moisture - every 9 days, or 40 times a year. The water in all the rivers on Earth changes completely in 12 days, or 30 times a year. Groundwater reserves and desert water are replenished more slowly. Least of all, this replenishment occurs in the polar glaciers - once in 8 thousand years, in Antarctica - in tens of millions of years.

With the water cycle, heat is transferred over the surface of the Earth, and water is also purified during evaporation. The water cycle in nature ensures the interconnection of the hydrosphere with the lithosphere, the air envelope of the Earth, flora and fauna.

Conclusion

There is no more important substance on Earth than ordinary water.

The planet's climate depends on water. Geophysicists say that the Earth would have cooled down long ago and turned into a lifeless piece of stone, if not for water. She has a very high heat capacity. When heated, it absorbs heat; cooling down, gives it away. Terrestrial water both absorbs and returns a lot of heat and thus "levels" the climate. And those water molecules that are scattered in the atmosphere - in clouds and in the form of vapors protect the Earth from cosmic cold.

Water is the main "building material" that makes up the human body and all other living organisms.

Water on Earth is in three states: liquid, solid and gaseous and can move from one state to another. Thanks to the processes: evaporation, transpiration, condensation, all waters participate in the world cycle. Therefore, water on Earth does not dry out.

The importance of the global water cycle on Earth is great. Imagine that atmospheric precipitation brought from the ocean has ceased to fall on land. Gradually, all the water on it will disappear, as part of it will evaporate, and part will drain into the ocean. Without water, neither plants nor animals can exist on land.

Due to the water cycle, all parts of the hydrosphere are closely united and interconnect other shells of our planet: the lithosphere, atmosphere, biosphere.

It is impossible to do without water - it is the most important substance on Earth.

And indeed - why, because thousands of fresh rivers flow into all the seas and oceans, and the water in them is very salty. Science has no answer to this question, like many others. But, despite this, in recent years, many discoveries have been made that allow shedding light on many things, including this mysterious question. The problem, as in many other cases, is that a significant part of the important discoveries simply do not reach the general public.

A similar situation has developed with the so-called "black smokers", known mainly only to specialists in geology and hydromorphology. "Black smokers", or hydrothermal vents of the mid-ocean ridges, are numerous springs operating on the ocean floor, confined to the axial parts of the mid-ocean ridges. It is from them that highly mineralized hot water constantly flows into the oceans under a pressure of hundreds of atmospheres. They are tubular formations, reaching a height of tens of meters, the stability of which, according to official science, is ensured by the action of the force of Archimedes.

Hydrothermal ocean vents, according to official scientists, carry dissolved elements from the oceanic crust into the oceans, while changing the crust itself and making a very significant contribution to the chemical composition of the oceans. Together with the cycle of oceanic crust generation at oceanic ridges and its recycling into the mantle, hydrothermal alteration produces a transfer of elements between the mantle and the oceans. The oceanic crust recycled into the mantle, as scientists see it, is responsible for some of the mantle heterogeneities.

According to scientists, hydrothermal springs are a kind of "oasis of life" in the deep aphotic zone of the ocean, existing not on the basis of photosynthesis, but on the basis of chemosynthesis of chemosynthetic bacteria. Recall that the aphotic zone is the deep water column of a reservoir, characterized by the complete absence of sunlight and the almost complete absence of photosynthesis. This is the habitat of unusual biological communities that ensure the formation of independent ecosystems. Thus, the deepest parts of the biosphere are confined to them, reaching a depth of 2500 meters or more.

Hydrothermal vents are believed to be a significant contributor to the Earth's heat balance. Beneath the median ridges, the mantle comes closest to the surface. According to scientists, sea water penetrates through cracks into the oceanic crust to a considerable depth, is heated by mantle heat due to thermal conductivity and is concentrated in magma chambers. Further, according to scientists, the internal pressure of superheated water in the chambers leads to the release of highly mineralized jets from sources at the bottom. In fact, of course, a real ongoing process

Their total contribution to the heat balance of the Earth is estimated to be about 20% of the total geothermal heat released - annually, "black smokers" spew about 3 10 to 9 tons of highly mineralized water heated to 350 ° C, and about 6 10 to 11 degrees - low-temperature sources (above 20 °C).

The deepest "smokers" discovered are located at a depth of 5000 m in the Cayman depression.

Along with "black smokers" there are also "white smokers", which vomit lighter-colored solutions and suspensions of minerals containing large amounts of barium, silicon and calcium.

In other words, it is "smokers" who are one of the main instruments of salinization of the oceans. But were the oceans always salty, or were they originally fresh, and their salinization began due to the processes of global change in the appearance of our planet that began at a certain stage? This question is still open.