Water on our planet is in three states - liquid, solid (ice, snow) and gaseous (steam). Currently, water occupies 3/4.

Water forms the water shell of our planet - the hydrosphere.

The hydrosphere (from the Greek words "hydro" - water, "sphere" - a ball) includes three main components: the oceans, land waters and water in the atmosphere. All parts of the hydrosphere are interconnected by the process of the water cycle in nature already known to you.

1. Explain how water from the continents enters the oceans.
2. How does water get into the atmosphere?
3. How does water get back to land?

The oceans account for over 96% of all water on our planet.

Continents and islands divide the World Ocean into separate oceans: Pacific, Atlantic, Indian,.

In recent years, the maps highlight the Southern Ocean - the body of water surrounding Antarctica. The largest in area is the Pacific Ocean, the smallest is the Arctic Ocean.

The parts of the oceans that protrude into the land and differ in the properties of their waters are called seas. There are a lot of them. The largest seas of the planet are the Philippine, Arabian, Coral.

Water in natural conditions contains various substances dissolved in it. 1 liter of ocean water contains on average 35 g of salt (most of all table salt), which gives it a salty taste, makes it unsuitable for drinking and use in industry and agriculture.

Rivers, lakes, swamps, glaciers and underground waters are land waters. Most of the land's waters are fresh, but salty ones are also found among lakes and groundwater.

You know what a huge role rivers, lakes, swamps play in nature and people's lives. But here's what is surprising: in the total amount of water on Earth, their share is very small - only 0.02%.

Much more water is enclosed in glaciers - about 2%. Do not confuse them with the ice that forms when water freezes. occur where more falls than has time to melt. Gradually, the snow accumulates, compacts and turns into ice. Glaciers cover about 1/10 of the land. They are located primarily on the mainland of Antarctica and the island of Greenland, which are covered with huge ice shells. Blocks of ice that break off along their shores form floating mountains - icebergs.

Some of them reach enormous sizes. Large areas are occupied by glaciers in the mountains, especially in such high places as the Himalayas, the Pamirs, and the Tien Shan.

Glaciers can be called pantries of fresh water. So far, it has hardly been used, but scientists have long been developing projects to transport icebergs to arid regions in order to provide local residents with drinking water.

They also make up about 2% of all water on Earth. They are located in the upper part of the earth's crust.

These waters can be salty and fresh, cold, warm and hot. Often they are saturated with substances useful for human health and are medicinal (mineral waters).

In many places, for example, along the banks of rivers, in ravines, groundwater comes to the surface, forming springs (they are also called springs and springs).

Groundwater reserves are replenished due to atmospheric precipitation, which seeps through some of the rocks that make up the earth's surface. Thus, groundwater is involved in nature.

Water in the atmosphere

Contains water vapor, water droplets and ice crystals. Together they make up fractions of a percent of the total amount of water on Earth. But without them, the water cycle on our planet would be impossible.

1. What is the hydrosphere? List its constituent parts.
2. What oceans form the World Ocean of our planet?
3. What makes up land water?
4. How are glaciers formed and where are they located?
5. What is the role of groundwater?
6. What is water in the atmosphere?
7. What is the difference between river, lake and ?
8. What is the danger of an iceberg?
9. Are there salt water bodies on our planet other than seas and oceans?

The water shell of the Earth is called the hydrosphere. It consists of the oceans, land waters and water in the atmosphere. All parts of the hydrosphere are interconnected by the process of the water cycle in nature. The oceans account for over 96% of the world's water. It is divided into separate oceans. The parts of the oceans that jut out into the land are called seas. Land waters include rivers, lakes, swamps, glaciers, groundwater. The atmosphere contains water vapor, water droplets and ice crystals.

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Question 1. What is the hydrosphere?

Question 2. What is the oceans?

The oceans are the main part of the hydrosphere, a continuous, but not continuous, water shell of the Earth, surrounding the continents and islands, and characterized by a common salt composition. The oceans cover almost 70% of the earth's surface.

Question 3. Can separate parts of the hydrosphere exist independently of each other?

The hydrosphere is formed by all types of natural waters, regardless of their state: liquid, solid and gaseous. All of them are interconnected by the water cycle.

Question 4. What is the hydrosphere?

The hydrosphere is the water shell of the Earth. The totality of the waters of the seas, oceans, continental reservoirs, rivers, underground sources, swamps and ice sheets of the Earth.

Question 5. List the components of the hydrosphere.

The hydrosphere is formed by all types of natural waters, regardless of their state: liquid, solid and gaseous.

Question 6. What part of the hydrosphere are the waters of the oceans?

Most of the water is concentrated in the oceans. 97% of all the waters of the planet are salty waters of the seas and oceans.

Question 7. What are the properties of the hydrosphere?

The hydrosphere unites all types of natural waters. Separate parts of the hydrosphere are connected into a single shell by the process of the water cycle.

Question 8. How does the hydrosphere affect the life of our planet?

Water is the basis of life on our planet. The role of water in the life of our planet, the individual components of nature, each living being is enormous. It is present in all organisms. The richness and diversity of nature directly depends on the availability of water.

Question 9. Give reasons in favor of the statement: "The hydrosphere forms a continuous shell of the Earth."

Separate parts of the hydrosphere are connected into a single shell by the process of the water cycle. Its main elements are the evaporation of water, the transfer of water vapor by the wind, precipitation, water runoff along river beds, and underground runoff.

Question 10. Why is water called the basis of life on Earth?

It is present in all organisms. Cell sap - cytoplasm - is an aqueous solution of various salts. All organisms on the planet are made up of cells. This means that water is the basis of life.

Question 11. Using the textbook illustrations, prove that all parts of the hydrosphere are connected by the water cycle.

Water evaporates from the surface of reservoirs. The salty waters of the World Ocean, like the fresh waters of rivers and lakes, turn into water vapor, which, concentrating, forms clouds. By the way, only water evaporates. The salts contained in sea water remain in the ocean. Therefore, water vapor and clouds are composed of fresh water. Clouds are carried by winds for hundreds and thousands of kilometers. Sooner or later, precipitation falls in the form of rain or snow. Part of the precipitation seeps into the soil and becomes part of the groundwater, while the other part flows into rivers. Melt waters formed during the melting of snow or mountain glaciers also partially seep and enter the groundwater, and partially enter the rivers. Rivers return water to lakes, seas and oceans.

To better understand what the atmosphere, hydrosphere, lithosphere is, it is necessary to consider such a term as "geographical shell".

The geographic shell is the totality of the geospheres of the Earth: the earth's crust, hydrosphere and atmosphere. They form a single whole and exist interconnectedly. Thus, solar energy is transformed into thermal, kinetic, electrical, chemical, etc. within the lithosphere. In the same place, it accumulates, is transferred to other spheres - air and water.

What is the hydrosphere

The term "hydrosphere" means the water shell of the Earth. This includes both surface (rivers, lakes, seas, oceans) and underground (ground) waters, as well as snow cover, glaciers, and steam in the atmosphere.

What is the hydrosphere? The definition of the concept is as follows: it is the totality of all the waters of our planet. The most important elements that make up the hydrosphere are rivers, swamps, lakes, glaciers and groundwater.

Rivers are of great importance, they carry masses of water over long distances. Marshes, like mountain glaciers, are a source of food for rivers. Glaciers are a reservoir of fresh water.

Reservoirs are artificial reservoirs created by man for economic activity.

The composition of the hydrosphere:

As can be seen from these data, the largest share of water falls on the World Ocean, and on the Earth's rivers - only 0.0001%. All these parts of the hydrosphere are interconnected, and water can move from one classification to another.

Water and its features

Water is a unique chemical element that is present on our planet in three states of aggregation. But the most useful is liquid, it is in this form that water is a necessary source for the existence of all living things. For many organisms, this is not just a source of food, but a habitat. It is proved that the first organisms lived in water, and only then, in the process of evolution, they came to land. Thus, the main characteristic of the hydrosphere is the presence of a huge number of living organisms.

What is the hydrosphere? We can say that this is the totality of the water of our planet.

Functions of the water shell

Let's single out some of the most important functions of the hydrosphere:

1. Accumulating. Water accumulates a huge amount of heat and provides a constant average temperature of the planet.
2. Oxygen production. As mentioned above, a large number of living organisms live in the water shell of the Earth, among which phytoplankton is present. It is he who produces most of the oxygen in the atmosphere. And oxygen, in turn, is necessary for the normal functioning of most organisms.
3. The hydrosphere, in particular the World Ocean, is a huge resource base. Various types of fish are caught here, and mineral resources are mined. Mankind also uses the water itself for various purposes: for purification, energy extraction, cooling, etc.
4. The water shell is an excellent breeding ground for various harmful microorganisms. It can transmit certain diseases.

Use of water resources

1. Water users. These are industries that use water for certain purposes, but do not return it. Among them are thermal power engineering, agriculture, ferrous and non-ferrous metallurgy, pulp and paper and chemical industries.
2. Water users. These are industries that use water for their needs, but then always return it. For example, household and drinking services, sea and river transport, shipping, and fisheries.

It should be noted that for the life support of a city with a population of 1 million people, more than 300 thousand m³ of clean water per day is needed, and more than 75% of the water is returned unsuitable for living organisms, i.e. contaminated.

Classification of waters by purpose

• Drinking water - used by man to quench his thirst. It should contain a minimum amount of toxic and chemical substances.
• Mineral water - extracted from underground sources by drilling. Used by humans for medicinal purposes.
• Industrial water is not necessarily water thoroughly purified from impurities, because. it is used in industry.
• Thermal energy water - thermal. It can be used in any branches of the national economy.

technical water

It is divided into several types:

1. Water for irrigation. Used in agriculture, does not require complex purification from impurities.
2. Energy water. It is used for space heating. Water is heated to a gaseous state.
3. Household water. It is used for various needs in hospitals, canteens, laundries and baths.

In industry, almost half of the water is used to cool equipment. In this case, it does not get dirty.

Process water also has several classifications. Allocate:

• flushing- used for washing various materials (solid, gaseous and liquid).
• Environment-forming- used for enrichment of ores, dissolution of rocks during mining.
• reactionary- used to speed up or slow down various reactions.

Irrational use of water and ways to solve problems

The biggest problem is the overuse of surface water. As a result, such regional cataclysms arise as the death of animals and plants, the drainage of swamps, and the drop in the water level in rivers.

In order to avoid overspending a valuable resource, it is necessary to use it rationally, create closed cycles of water use in industry, and save at the household level.

Groundwater is overused due to increased abstraction and reduced rainfall, when underground storage facilities do not have time to replenish depleted reserves. To solve this problem, it is necessary to take into account the characteristics of the territory from which water is taken.

If you do not respond to the above problem in time, the next one may occur - soil subsidence. When underground sources are depleted, cavities appear in the bowels of the earth, the soil is no longer supported by anything and settles. This is dangerous because the drawdown can be unexpected in places where people are.

To prevent this problem from being taken by surprise, it is necessary to reduce the consumption of groundwater, install high-quality filters for the reuse of the waste fluid.

Another problem that arises from the excessive use of groundwater is the inflow of salt water. This is due to a decrease in pressure inside the cavities as a result of a decrease in the groundwater level.

Water pollution

What is hydrosphere pollution? This water pollution is one of the global problems of mankind. There is a glut of oil products. For purification, it is necessary to catch not only the oils floating on the surface, but also the sediment that sinks to the bottom. The chemical industry is one of the main sources of pollution not only of the hydrosphere, but also of the atmosphere.

The pulp and paper industry litters nearby areas with insoluble fibers and other substances. Because of this, the water has an unpleasant smell and taste, changes color, and increases the growth of bacteria and fungi.

CHP plants discharge waste water back into water bodies. Considering that it is usually much warmer, one can understand that the entire reservoir is heating up. This adversely affects the local flora and fauna. The waters begin to bloom, because. the growth of cyanobacteria, algae and other vegetation is enhanced. The liquid acquires an unpleasant odor and taste.

Rafting timber also adversely affects the state of water. Rivers are clogged and polluted. In addition, this economic activity harms the fish and animals that live in the river along which the rafting takes place. Young fish and eggs die from lack of oxygen. The species composition is decreasing.

Human activity harms the environment, especially the hydrosphere and biosphere. Wastewater from sewers ends up in the ground, harmful substances get not only into the soil, but also into groundwater, rivers and lakes. In addition to harmful organic substances, wastewater contains various impurities: radioactive elements, heavy metals, products of organic synthesis.

Water has a unique property - it can self-renew and self-purify thanks to solar energy.

The earth's hydrosphere is a fragile structure. To solve the problem of its pollution, it is necessary to take a number of measures:

• providing each enterprise with a modern water treatment plant;
• installation of high-quality filters for domestic water;
• improvement of closed cycles of water consumption.

Perhaps everyone knows what the hydrosphere is and how important it is, but not many people think about the catastrophic rate of water pollution. If everyone made an effort to save clean water, the disaster would not be so massive. The earth's hydrosphere will never fully recover, but humanity can make sure that the current reserves are not contaminated.

Hydrosphere - the water shell of our planet, includes all water, chemically unbound, regardless of its state (liquid, gaseous, solid). The hydrosphere is one of the geospheres located between the atmosphere and the lithosphere. This discontinuous envelope includes all oceans, seas, continental fresh and salt water bodies, ice masses, atmospheric water, and water in living things.

Approximately 70% of the Earth's surface is covered by the hydrosphere. Its volume is about 1400 million cubic meters, which is 1/800 of the volume of the entire planet. 98% of the waters of the hydrosphere is the World Ocean, 1.6% is enclosed in continental ice, the rest of the hydrosphere falls on the share of fresh rivers, lakes, groundwater. Thus, the hydrosphere is divided into the World Ocean, groundwater and continental water, and each group, in turn, includes subgroups of lower levels. So, in the atmosphere, water is in the stratosphere and troposphere, on the earth's surface the waters of the oceans, seas, rivers, lakes, glaciers are released, in the lithosphere - the waters of the sedimentary cover, the foundation.

Despite the fact that the bulk of water is concentrated in the oceans and seas, and only a small part of the hydrosphere (0.3%) accounts for surface waters, they play the main role in the existence of the Earth's biosphere. Surface water is the main source of water supply, watering and irrigation. In the water exchange zone, fresh groundwater is rapidly renewed in the course of the general water cycle, therefore, with rational exploitation, it can be used indefinitely.

During the development of the young Earth, the hydrosphere was formed during the formation of the lithosphere, which, over the geological history of our planet, has released a huge amount of water vapor and underground magmatic waters. The hydrosphere was formed during the long evolution of the Earth and the differentiation of its structural components. Life was born in the hydrosphere for the first time on Earth. Later, at the beginning of the Paleozoic era, the emergence of living organisms on land took place, and their gradual settlement on the continents began. Life without water is impossible. The tissues of all living organisms contain up to 70-80% water.

The waters of the hydrosphere constantly interact with the atmosphere, the earth's crust, the lithosphere, and the biosphere. At the boundary between the hydrosphere and the lithosphere, almost all sedimentary rocks are formed that make up the sedimentary layer of the earth's crust. The hydrosphere can be considered as part of the biosphere, since it is completely populated by living organisms, which, in turn, affect the composition of the hydrosphere. The interaction of the waters of the hydrosphere, the transition of water from one state to another manifests itself as a complex water cycle in nature. All types of water cycle of various volumes represent a single hydrological cycle, during which the renewal of all types of water is carried out. The hydrosphere is an open system, the waters of which are closely interconnected, which determines the unity of the hydrosphere as a natural system and the mutual influence of the hydrosphere and other geospheres.

Related content:

The hydrosphere is the water shell of the Earth, which includes the World Ocean, land waters (rivers, lakes, swamps, glaciers), groundwater. Water plays the most important role in the history of the development of our planet, since the origin and development of living matter, and, consequently, the entire biosphere (?!) is associated with it.

The bulk of the water is concentrated in the seas and oceans - almost 94%, and the remaining 6% falls on other parts of the hydrosphere (Table 4).

Table 4

Distribution of water in the Earth's hydrosphere (M.I. Lvovich, 1986)

The area of ​​the hydrosphere is 70.8% of the surface area of ​​the globe, while its volume is only about 0.1 % the volume of the planet. The thickness of a uniformly distributed film over the Earth's surface is only 0.03% of its diameter. The proportion of surface water in the hydrosphere is very small, but they are extremely active (changing on average every 11 days), and this is the beginning of the formation of almost all sources of fresh water on land. The amount of fresh water is 2.5% of the total, with almost two thirds

This water is enclosed in the glaciers of Antarctica, Greenland, polar islands, ice floes and icebergs, mountain peaks. Groundwater is at different depths (up to 200 m or more); deep underground aquifers are mineralized and sometimes saline. In addition to water in the hydrosphere itself, water vapor in the atmosphere, groundwater in soils and the earth's crust, there is biological water in living organisms. With a total mass of living matter in the biosphere of 1400 billion tons, the mass of biological water is 80 % or 1120 billion tons (Table 5).

Table 5

The average annual water balance of the globe

Surface	Bad, million km	Volume, km;
		evaporation
Earth
World Ocean
Including the area of ​​runoff into the ocean
The area of ​​runoff that does not reach the ocean (internal runoff)

Fresh water plays the main role in the life of living organisms on land. Fresh water is called water, the salinity of which does not exceed 1%, i.e., containing no more than 1 g of salts in 1 liter (the salinity of ocean water is about 35%). According to available estimates, the total world fresh water resources amount to a total runoff - 38-45 thousand km 3, water reserves in fresh lakes - 230 thousand km 1, and soil moisture - 75 thousand km 1. The annual volume of moisture evaporating from the surface of the planet (including transpiration by plants) is estimated at about 500-575 thousand km 1, and 430-500 thousand km 3 evaporates from the surface of the World Ocean, thus, a little more than 70 thousand km3 falls on the land. km 3 of evaporating moisture. During the same time, 120 thousand km 3 of water falls in the form of precipitation on all continents (Table 6).

An analysis of the Earth's water balance shows that the total amount of precipitation falling on the surface of the World Ocean is always less than evaporation, since part of the evaporated water is carried away to land and falls there as precipitation. On average, a layer of water equal to 1400 mm annually evaporates from the surface of the ocean, and 1270 mm of precipitation falls. The difference is balanced by river runoff into the ocean. On land, on the contrary, the amount of precipitation is greater than the amount of evaporated moisture, up to 38 % all precipitation is carried away by river runoff to the ocean.

Table 6

Water balance and fresh water resources of the continents and land in general*

Continents	Area, mln km		river runoff	hydration territory	Evaporation
Northern America**
South America
Australia ***
All land ****

# In the numerator the values ​​are given in mm, in the denominator the volume is in km 1 .

• f Including Central America, excluding the Canadian Arctic Archipelago.
• Including Tasmania, New Guinea. New Zealand.

Excluding Antarctica, Greenland, Canadian Arctic Archipelago.

South America is the richest in water resources per unit area, followed by Europe, Asia and North America. In terms of river runoff, Asia is the most endowed with water resources. Despite the uneven distribution of fresh water across the continents of the Earth, in general, they still provide the biosphere.

Water is the most common mineral on earth. IN AND. Vernadsky wrote that water stands apart in the history of our planet. There is no natural body that could compare with it in terms of its influence on the course of the main, most grandiose geological processes. There is no earthly substance - a mineral, a rock, a living body, which would not contain it. All earthly matter is permeated and embraced by it. Pure, free of impurities, the water is clear, colorless and odorless. This is the only mineral on our planet that occurs naturally in three states of aggregation: gaseous, liquid and solid. Water can be considered from a chemical point of view as hydrogen oxide or oxygen hydride. In table. 7 shows the melting and boiling points of compounds close in composition to water.

Table data analysis. 7 as well as Fig. 13 shows the illogicality of the behavior of water: the transitions of water from a solid state to liquid and gaseous occur at temperatures much higher than they should. The anomalous behavior is due to the structure of the water molecule H 2 0; it is built in the form of an obtuse triangle: the angle between two oxygen-hydrogen bonds is 104 ° 27 "(Fig. 14). But, since both hydrogen atoms are located one hundred

Ron from oxygen, electric charges in it disperse, and the water molecule acquires polarity. Polarity is the reason for the chemical interaction between different water molecules. Hydrogen atoms in the H 2 0 molecule, having a partial positive charge, interact with the electrons of the oxygen atoms of neighboring molecules. This chemical bond is called hydrogen. It combines water molecules into unique polymers of spatial structure; the plane in which the hydrogen bonds are located is perpendicular to the plane of the atoms of the same water molecule. The interaction between H 2 0 molecules explains the anomalously high melting and boiling points. In order to “loosen” hydrogen bonds, significant additional energy is needed, which, in particular, explains the high heat capacity of water.

Table 7

Melting and boiling points of hydrogen compounds of the main elements

subgroups of group VI of the periodic system

Ice crystals are formed from analogous associates (combinations of molecules). The atoms in an ice crystal are "packed" loosely, and in connection with this, ice does not conduct heat well. The density of liquid water at a temperature close to zero is greater than that of ice. At 0 ° C, 1 g of ice occupies a volume of 1.0905 cm 3, 1 g of liquid water - 1.0001 cm 5. Therefore, ice has buoyancy and therefore reservoirs do not freeze to the bottom, but only have an ice cover.

Rice. 13.

four element hydrides

This is another anomaly of water. After melting, water first contracts and only then, at a temperature of 4 ° C and above, does it begin to expand.

Rice. 15. Phase diagram of water: /- VI- ice modifications

• 60 50 40 30 * 20 10 about
• -20 -30
• -40 -50

Special methods were used to obtain ice-N and ice-Sh - heavier and denser crystalline forms of solid water (Fig. 15) (the hardest, densest and most refractory ice-UP was obtained at a pressure of 3 billion Pa; its melting point is +190 * C) .

Of the chemical properties of water, one of the most important is the ability of its molecules to dissociate, i.e., decomposition into ions, as well as the colossal ability (activity) to dissolve substances of various chemical nature.

The role of water as the main and universal solvent is determined primarily by the polarity of its molecules and, as a consequence, its extremely high dielectric constant. Opposite electrical charges, and in particular ions, are attracted to each other in water 80 times weaker than they would be attracted to air. In this case, it is easier for thermal motion to separate the molecules. That is why dissolution occurs, including many hardly soluble substances: it is not in vain that they say: "Water wears away a stone."

Dissociation (disintegration) of water molecules into ions under normal conditions is very small: one molecule out of half a billion dissociates. It should be noted that of the above reactions, the first one is conditional, since a proton H without an electron shell cannot exist in an aqueous medium; it instantly combines with a water molecule, forming a hydroxonium ion H 3 SG:

H 3 0-> H + OH,

2H 2 0 -> H,0* + OH

It is fundamentally possible that the associates of water molecules decompose into very heavy ions, such as: 8H 2 0 H 9 0^ + H 7 0 4 ,

and the reaction H 2 0 - "H + + OH" is just a schematic general representation of more complex reactions.

Water is weakly reactive. Some active metals are able to displace hydrogen from it:

• 2Na + 2H g O -> 2NOH + H / G, and in an atmosphere of free fluorine it can burn:
• 2P 2 + 2H g O -> 4HP + 0,

V.P. Zhuravlev et al. (1995) cites the data of G.V. Vasiliev on the very diverse characteristics of water, in particular, anomalous water (or superwater) reaches its maximum density at { = \u003d -10 ° C, its viscosity is 10-15 times less than classical water, it has polymers (H,0) 5 and (H 2 0) 4.

The presence of super-anomalous water has been established, which does not have a maximum density, does not crystallize (even at -100 * C), but vitrifies like resin. Acad. A.N. Frumkin believes that this new fourth state of aggregation of water is resinous and puts it on a par with the discovery of new chemical elements.

Metabolic water is a special liquid that is produced by a living organism, which has the property of counteracting “drying out”, in other words, “aging”; metabolic water, according to some scientists, is itself capable of aging and turning into "dead" water.

G.V. Vasiliev allocates "melt" water, which increases productivity; "magnetic" water that prevents carbonate formation; "electric" water, accelerating the flowering of some plants; "dry" water, consisting of 90 % H 2 0 and 10 % H 2 8O 4 , as well as 71-water, "black", "remembering", etc. Many of these types of water have specific properties, some are hypothetical. However, it was noted that water dissolves almost all substances, except for fats and a very limited number of minerals. Therefore, in nature there is no practically pure water, it is always a solution of a greater or lesser concentration.

Water is a liquid, i.e., a mobile body, which allows it to penetrate into a wide variety of bodies and environments and move in different directions, while simultaneously transporting substances dissolved in it. In this way, it ensures the exchange of substances in the geographical envelope, including between living organisms and the environment. Water is able to overcome gravity even in a liquid state, rising through the thinnest capillaries. This determines the possibilities of water circulation in rocks and soils; blood circulation in animals; the movement of plant juices up the stems. Water has the ability to wet, "stick" to various surfaces. Electric forces of interaction are capable of binding water around solid particles of minerals, significantly changing its characteristics. For example, its freezing temperature becomes equal to - 4 ° C, density - up to 1.4 g / cm

The origin of water on Earth has not yet been fully explained: some experts believe that it was formed as a result of synthesis from hydrogen and oxygen during their release from the bowels of the Earth in the early stages of its existence, while others, following Acad. O.Yu. Schmidt, suggest that water came to Earth during the formation of the planet from outer space.

The oceans are the water shell of the Earth, with the exception of water bodies on land and the glaciers of Antarctica, Greenland, polar archipelagos and mountain peaks. The world ocean is divided into four main parts - Pacific, Atlantic, Indian, Arctic oceans. The waters of the World Ocean, going into the land, form seas and bays. The seas are relatively isolated parts of the ocean (for example, the Black, Baltic, etc.), and the bays do not protrude into the land as much as the seas, and in terms of the properties of the waters differ little from the World Ocean. In the seas, the salinity of water can be higher than oceanic (35%), as, for example, in the Red Sea - up to 40%, or lower, as in the Baltic Sea - from 3 to 20 %.

The waters of the World Ocean and its constituent parts have some common features:

• they all communicate with each other;
• the level of the water surface in them is almost the same;
• salinity averages 35%, has a bitter-salty taste due to the large amount of mineral salts dissolved in them (Fig. 16).

In addition to salts, various gases are dissolved in ocean water, the most important of which is oxygen, which is necessary for breathing.

Supralittoral

• 11000

Rice. 16. Ecological regions of the ocean

living organisms. In different parts of the World Ocean, the amount of dissolved oxygen is different, which depends on the temperature of the water and its composition. The presence of carbon dioxide in ocean water makes photosynthesis possible, and also allows some marine animals to form shells and skeletons as a result of life processes.

Temperature,°С О 5 10 15 20 25

Fig, ]7, Typical distribution of water temperature by depth:

/ - high latitudes; 2- temperate latitudes (summer); 3 - tropics

Water temperatures in the oceans range from freezing in the polar seas to 28°C at the equator (Figure 17).

The waters of the oceans are in constant motion in the form of waves, sea currents and tides. Waves arise under the influence of wind and sea quakes; sea ​​currents are formed under the influence of constant winds and the difference in the density of ocean water; ebbs and flows of ocean water are associated with the attraction of the moon and the rotation of the earth around its axis (Fig. 18).

Groundwater is water located in pores, cracks, caverns, voids, caves in the thickness of rocks under the surface of the Earth. These waters can be in liquid, solid and gaseous states. Groundwater and surface water are interconnected: in some cases, some are feeding zones, others are discharge zones, in other cases, vice versa. Groundwater has a different origin and is divided into:

• juvenile, formed (according to the hypothesis of M. V. Lomonosov) during magma processes;
• infiltration, formed due to the infiltration of atmospheric precipitation through the thickness of permeable soils and soils and accumulated on impervious layers;
• condensation, accumulated in rocks during the transition of water vapor in the ground atmosphere into a liquid state;
• water buried by sediments in surface water bodies.

It is practically impossible to establish the genesis of groundwater by its characteristics, and there is no special need for this, much more important is the state of water in soils and soils. Water,

Rice. 18. The system of surface currents of the World Ocean in winter 1 - warm current; 2- cold current; 3 - areas of development of secondary monsoons; 4 -

tropical and and clones

held by molecular forces, almost does not participate in the processes that ensure the vital activity of organisms, in particular, plants cannot use this water with the help of their root system. Capillary and gravitational water is suitable for these purposes. The latter includes groundwater, which moves in the depths of the earth's crust under the influence of the Earth's gravity. Groundwater has a different temperature, basically it corresponds to the temperature of the host rocks, but deep groundwater, located near magma chambers, is a source of hot water. In Russia, they are discovered in Kamchatka, the North Caucasus, where their temperature reaches 70-95 °C. Gushing hot springs are called geysers. More than 20 of them have been discovered in the valley of geysers in Kamchatka, among them such as the “Giant”, which gives a fountain 30 m high, or the “Old Faithful” (Yellowstone, USA), which gushes at regular intervals. Geysers are also common in Iceland and New Zealand.

When filtered through rocks with different mineral and chemical compositions, groundwater naturally replenishes itself with dissolved substances. This is how mineral waters are gradually formed, which are sometimes saturated with carbon dioxide, hydrogen sulfide. Some of these waters are of medical and resort importance.

Surface waters of land. Rivers. In general, on the surface of the earth's land, waters move in various forms: rivers, streams, springs, temporary streams. Recently, man-made watercourses (channels) have become of serious importance.

Rivers and streams are permanent streams located in natural relief depressions. The sizes of the rivers are very different: from huge ones (the Amazon River) to rivers that are known to almost every person because they can be stepped over. The high water content of the deepest river in the world, the Amazon - 3160 km 3 per year - is explained by the huge area of ​​\u200b\u200bthe basin (about 7 million km 2) and the abundance of precipitation (more than 2000 mm per year). The Amazon has 17 tributaries of the so-called first order, each of which is equal to the Volga River in terms of high water content.

Streams are even smaller natural watercourses with a width of no more than 0.5-1.0 m.

Rivers form a river network in a certain area from the main channel and tributaries. Rivers are fed from a certain area, called its basin. Groundwater, melt water from snow and glaciers, and rainfall are permanent sources of river nutrition. Depending on the feeding conditions, a regime is formed near the rivers; According to the water level, periods of high and low water are distinguished. They were named: flood, high water and low water.

Rivers perform colossal erosion and accumulation work. They erode rocks, form channels, and the resulting material is transferred and deposited in the form of alluvial (river) deposits, creating a floodplain and accumulative terraces near the bedrock banks. There are young and old rivers. The latter, as a rule, have wide developed valleys with abandoned old winding channels (oxbow lakes), a large number of terraces and wide floodplains. Young rivers often have rapids and waterfalls (areas where water falls from high ledges). One of the largest waterfalls in the world - Victoria on the river. Zambezi - falls from a height of 120 m with a width of 1800 m; Niagara Falls - height 51 m, stream width 1237 m. Many mountain waterfalls are even higher. The highest of them is Angel on the river. Orinoco - 1054 m high.

Lakes. In addition to watercourses, where water moves from higher to lower elevations, there are permanent reservoirs on land in natural relief depressions. On the territory of our country there is part of the largest lake in the world - the Caspian Sea and the deepest - Lake Baikal. Lakes were formed in various ways: from volcanic craters to tectonic troughs and karst sinkholes; sometimes there are dammed lakes during landslides and mudflows in the mountains. A large number of lakes, which are located in Finland, Sweden, Karelia (Russia), Canada, were formed during the advance and retreat of glaciers during periods of glaciation. Most of the lakes are filled with fresh water, but there are also salty ones, such as the Caspian, Aral and some others. Fresh have a salinity of less than 1%, brackish - more than 1%, salty - more than 24.7%.

Lakes develop depending on the surrounding conditions. Rivers, temporary water flows bring to the lakes a huge amount of inorganic and organic substances that are deposited on their bottom. Vegetation appears, the remains of which also accumulate, filling the lake basins, and give rise to the formation of swamps (Fig. 19).

Rice. 19.

I- moss cover (ryam); 2 - bottom sediments of organic residues; 3 - "window" go

clean water area

6 )

Rice. 20. Lowland ( a) and upland (o) swamps

Swamps are overly moist areas of land covered with moisture-loving vegetation. Waterlogging in the forest belt often occurs as a result of deforestation. The tundra is a zone where permafrost does not allow water to penetrate into the soil and its gradual accumulation leads to the formation of swamps.

According to the nutritional conditions and location, the swamps are divided into lowland and riding(Fig. 20). The former are fed by precipitation, groundwater and surface water. A large amount of mineral components coming from groundwater contributes to the active development of vegetation and its high productivity. Under certain conditions, lowland bogs turn into so-called upland bogs. In these swamps, peat formation is carried out - a very complex geochemical process of mineral formation and sedimentation. The accumulation of peat, on the one hand, increases the reserves of fertility in the earth's interior by increasing the volume of humus, and also contributes to the conservation of excess carbon, but, on the other hand, significantly impoverishes the mineral component that feeds plants in the swamp. There is a replacement with less demanding plants, such as sphagnum mosses, which release organic acids that slow down peat formation. Water no longer enters the zones of development of sphagnum mosses, and the process of destruction of vegetation gradually develops more and more.

The considerable attention paid to swamps is due to the fact that they occupy vast areas on the territory of our country and often represent the sources of significant surface watercourses. But this is not the only thing, the fact of the determining influence of the swamp on the existence of the forest has recently been established, that is, there is a deep connection between the optimal conditions for the development of forest ecosystems and the swamps existing in them, and many small lakes.

Water is of paramount importance for the functioning of living organisms. This is the main medium of biochemical reactions, and, ultimately, an absolutely necessary component of protoplasm. Nutrients are transported inside living organisms in the form of aqueous solutions, and water also transports and removes dissimilation products from organisms (I.A. Shilov, 2000). The relative water content in living organisms ranges from 50 to 95% (95% of water is contained in the body of jellyfish, and in the tissues of many mollusks up to 92%). The intracellular and intercellular metabolism depends on the amount of water and dissolved salts, and in hydrobionts, the osmotic relationship with the environment. Most terrestrial animals can only perform gas exchange with the environment in the presence of wet surfaces; moisture also during its evaporation contributes to the formation of a thermal balance between the changing temperature parameters of the environment and the warmth of organisms.

I.A. Shilov (2000) describes the water exchange between organisms and the environment as an exchange consisting of two opposite processes, one of which is the entry of water into the body, the other is its return to the external environment. In higher plants, this process is “sucking” water from the soil by the root system, carrying it (together with dissolved substances) to individual organs and cells and excreting it in the process of transpiration. Of the total volume, 5% of water is used for photosynthesis, and the rest to maintain turgor (internal hydrostatic pressure in living cells, causing tension in the cell membrane).

Animals get water mainly by drinking, and this way for most of them, even for aquatic ones, is not only necessary, but also the only one. Excretion of water occurs with urine or excrement, as well as by evaporation. Individual organisms living in the aquatic environment are able to receive and give water either through their integuments or through specialized areas of tissues that are permeable to water. This also applies to terrestrial inhabitants: for many plants, invertebrates and amphibians, it is typical to receive water from sources such as dew, fog, rain.

For animals, one of the sources of water is food. At the same time, its significance in water metabolism is not limited to the water content in the tissues of food objects. Enhanced nutrition is accompanied by the accumulation of fat reserves in the body, which are important both as an energy reserve and as an internal source of water entering cells and tissues. Water exchange is directly related to the exchange of salts. A certain set of salts (ions) is a necessary condition for the normal functioning of the body, since salts are part of the composition of tissues and play a certain role in the metabolic mechanisms of cells. If there are disturbances in the amount of incoming water and, accordingly, the necessary salts, then the complete balance is disturbed and shifts in osmotic processes occur.

For all living organisms, the most important is the maintenance of a stable water-salt metabolism as the main factor in the implementation of their vital functions.