World Ocean. The World Ocean and its parts. The structure of the oceans. The movement of the waters of the oceans. Bottom sediments of the World Ocean Gas composition of ocean water

The structure of the World Ocean is its structure - vertical stratification of waters, horizontal (geographical) zonality, the nature of water masses and ocean fronts.

Vertical stratification of the World Ocean. In a vertical section, the water column breaks up into large layers, similar to the layers of the atmosphere. They are also called spheres. The following four spheres (layers) are distinguished:

Upper sphere is formed by direct exchange of energy and matter with the troposphere in the form of microcirculation systems. It covers a layer of 200-300 m thick. This upper sphere is characterized by intense mixing, light penetration and significant temperature fluctuations.

Upper sphere breaks down into the following particular layers:

a) the uppermost layer is several tens of centimeters thick;

b) wind effect layer with a depth of 10-40 cm; he participates in excitement, reacts to the weather;

c) a layer of temperature jump, in which it drops sharply from the upper heated layer to the lower layer, not affected by waves and not heated;

d) penetration layer of seasonal circulation and temperature variability.

Ocean currents usually capture water masses only in the upper sphere.

Intermediate sphere extends to depths of 1500 - 2000 m; its waters are formed from surface waters when they sink. At the same time, they are cooled and compacted, and then mixed in horizontal directions, mainly with a zonal component. Horizontal transfers of water masses predominate.

Deep Sphere does not reach the bottom by about 1,000 m. This sphere is characterized by a certain uniformity. Its thickness is about 2,000 m and it concentrates more than 50% of all the water of the World Ocean.

bottom sphere occupies the lowest layer of the ocean and extends to a distance of about 1,000 m from the bottom. The waters of this sphere are formed in cold zones, in the Arctic and Antarctic, and move over vast expanses along deep basins and trenches. They perceive heat from the bowels of the Earth and interact with the ocean floor. Therefore, during their movement, they are significantly transformed.

Water masses and ocean fronts of the upper sphere of the ocean. A water mass is a relatively large volume of water that forms in a certain area of ​​the World Ocean and has almost constant physical (temperature, light), chemical (gases) and biological (plankton) properties for a long time. The water mass moves as a whole. One mass is separated from another by an ocean front.

The following types of water masses are distinguished:

1. Equatorial water masses limited by the equatorial and subequatorial fronts. They are characterized by the highest temperature in the open ocean, low salinity (up to 34-32 ‰), minimum density, high content of oxygen and phosphates.

2. Tropical and subtropical water masses are formed in the areas of tropical atmospheric anticyclones and are limited from the side of the temperate zones by the tropical northern and tropical southern fronts, and the subtropical ones by the northern temperate and northern southern fronts. They are characterized by high salinity (up to 37 ‰ and more), high transparency, lack of nutrient salts and plankton. Ecologically, tropical water masses are oceanic deserts.

3. Moderate water masses are located in temperate latitudes and are limited from the side of the poles by the Arctic and Antarctic fronts. They are characterized by great variability of properties both in geographical latitudes and in seasons. Moderate water masses are characterized by an intense exchange of heat and moisture with the atmosphere.

4. Polar water masses The Arctic and Antarctic are characterized by the lowest temperature, the highest density, and the highest oxygen content. The waters of the Antarctic sink intensively into the near-bottom sphere and supply it with oxygen.

ocean currents. In accordance with the zonal distribution of solar energy over the surface of the planet, similar and genetically related circulation systems are created both in the ocean and in the atmosphere. The old assumption that ocean currents are caused solely by winds is not supported by the latest scientific research. The movement of both water and air masses is determined by zoning common to the atmosphere and hydrosphere: uneven heating and cooling of the Earth's surface. From this, in some areas, ascending currents and a decrease in mass arise, in others - descending currents and an increase in mass (of air or water). Thus, an impulse of movement is born. The transfer of masses is their adaptation to the field of gravity, the desire for a uniform distribution.

Most macrocirculatory systems last all year. Only in the northern part indian ocean currents change with the monsoons.

In total, there are 10 major circulation systems on Earth:

1) North Atlantic (Azores) system;

2) North Pacific (Hawaiian) system;

3) South Atlantic system;

4) South Pacific system;

5) South Indian system;

6) Equatorial system;

7) Atlantic (Icelandic) system;

8) Pacific (Aleutian) system;

9) Indian monsoon system;

10) Antarctic and Arctic system.

The main circulation systems coincide with the centers of action of the atmosphere. This commonality is genetic in nature.

The surface current deviates from the direction of the wind at an angle of up to 45 0 to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. Thus, the trade winds flow from east to west, while the trade winds blow from the northeast in the Northern Hemisphere and from the southeast in the Southern Hemisphere. The top layer can follow the wind. However, each underlying layer continues to deviate to the right (left) from the direction of movement of the overlying layer. In this case, the flow rate decreases. At a certain depth, the current takes the opposite direction, which practically means its termination. Numerous measurements have shown that currents end at depths of no more than 300 m.

In the geographical envelope as a system of a higher level than the oceanosphere, ocean currents are not only water flows, but also air mass transfer bands, directions of matter and energy exchange, migration routes of animals and plants.

Tropical anticyclonic systems of ocean currents are the largest. They extend from one coast of the ocean to another for 6-7 thousand km in the Atlantic Ocean and 14-15 thousand km in the Pacific Ocean, and along the meridian from the equator to 40 ° latitude, for 4-5 thousand km. Steady and powerful currents, especially in the Northern Hemisphere, are mostly closed.

As in tropical atmospheric highs, the movement of water is clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. From the eastern shores of the oceans (the western shores of the mainland), surface water belongs to the equator, rises from the depths (divergence) in its place, and cold comes in compensation from temperate latitudes. This is how cold currents are formed:

Canarian cold current;

California cold current;

Peruvian cold current;

Benguela cold current;

West Australian cold current, etc.

The speed of the currents is relatively small and is about 10 cm/sec.

Jets of compensatory currents flow into the Northern and Southern Equatorial (Equatorial) warm currents. The speed of these currents is quite high: 25-50 cm/sec on the tropical periphery and up to 150-200 cm/sec near the equator.

Approaching the shores of the continents, the trade winds naturally deviate. Large sewer currents are formed:

Brazilian current;

Guiana current;

Antilles current;

East Australian Current;

Madagascar current, etc.

The speed of these currents is about 75-100 cm/sec.

Due to the deflecting effect of the Earth's rotation, the center of the anticyclonic system of currents is shifted to the west relative to the center of the atmospheric anticyclone. Therefore, the transfer of water masses to temperate latitudes is concentrated in narrow bands near the western coasts of the oceans.

Guiana and Antilles currents wash the Antilles and most of the water enters the Gulf of Mexico. From it begins the flow of the Gulf Stream. Its initial section in the Florida Strait is called Florida Current, the depth of which is about 700 m, width - 75 km, thickness - 25 million m 3 / sec. The water temperature here reaches 26 0 C. Having reached the middle latitudes, the water masses partially return to the same system near the western coasts of the continents, and are partially involved in the cyclonic systems of the temperate zone.

The equatorial system is represented by the Equatorial countercurrent. equatorial countercurrent formed as a compensation between the trade wind currents.

The cyclonic systems of temperate latitudes are different in the northern and southern hemispheres and depend on the location of the continents. Northern cyclonic systems - Icelandic and Aleutian- very extensive: from west to east they stretch for 5-6 thousand km and from north to south about 2 thousand km. The circulation system in the North Atlantic begins with the warm North Atlantic Current. It often retains the name of the initial gulf stream. However, the Gulf Stream proper as a drain continues no further than the New Foundland Bank. Starting from 40 0 ​​N.S. water masses are involved in the circulation of temperate latitudes and, under the influence of western transport and the Coriolis force, are directed from the coasts of America to Europe. Due to the active water exchange with the Arctic Ocean, the North Atlantic Current penetrates into the polar latitudes, where cyclonic activity forms several currents. Irminger, Norwegian, Svalbard, North Cape.

Gulf Stream in a narrow sense, it is called a runoff current from the Gulf of Mexico to 40 0 ​​N, in a broad sense, a system of currents in the North Atlantic and the western part of the Arctic Ocean.

The second gyre is located off the northeastern coast of America and includes currents East Greenland and Labrador. They take out in Atlantic Ocean the bulk of Arctic waters and ice.

The circulation of the northern part of the Pacific Ocean is similar to the North Atlantic, but differs from it in a smaller water exchange with the Arctic Ocean. Stock current Kuroshio goes into North Pacific heading towards Northwest America. Very often this system of currents is called Kuroshio.

A relatively small (36 thousand km 3) mass of ocean water penetrates into the Arctic Ocean. The cold currents of the Aleutian, Kamchatka and Oyashio are formed from the cold waters of the Pacific Ocean without connection with the Arctic.

Circumpolar Antarctic System of the Southern Ocean, respectively, the oceanicity of the Southern Hemisphere is represented by one current Western winds. This is the most powerful current in the oceans. It covers the Earth in a continuous ring in the belt from 35-40 to 50-60 0 S.L. Its width is about 2,000 km, its thickness is 185–215 km3/s, and its speed is 25–30 cm/s. To a large extent, this current determines the independence of the Southern Ocean.

The circumpolar course of the Western winds is not closed: branches depart from it, flowing into Peruvian, Benguela, Western Australian currents, and from the south, from Antarctica, coastal Antarctic currents flow into it - from the Weddell and Ross seas.

The Arctic system occupies a special place in the circulation of the waters of the World Ocean due to the configuration of the Arctic Ocean. Genetically, it corresponds to the Arctic baric maximum and the trough of the Icelandic minimum. The main current here is Western arctic. It moves water and ice from east to west throughout the Arctic Ocean to the Nansen Strait (between Svalbard and Greenland). Then it continues East Greenland and Labrador. In the east, in the Chukchi Sea, it separates from the Western Arctic Current polar current, going through the pole to Greenland and further - to the Nansen Strait.

The circulation of the waters of the World Ocean is dissymmetric with respect to the equator. The dissymmetry of currents has not yet received a proper scientific explanation. The reason for this probably lies in the fact that north of the equator the meridional transport dominates, while in the Southern Hemisphere it is zonal. This is also explained by the position and shape of the continents.

In inland seas, water circulation is always individual.

54. Land waters. Types of land waters

Atmospheric precipitation, after falling on the surface of continents and islands, is divided into four unequal and variable parts: one evaporates and is transported further inland by atmospheric runoff; the second seeps into the soil and into the soil and is retained for some time in the form of soil and underground water, flowing into rivers and seas in the form of groundwater runoff; the third in streams and rivers flows into the seas and oceans, forming surface runoff; the fourth turns into mountain or continental glaciers, which melt and flow into the ocean. Accordingly, four types of water accumulation are distinguished on land: groundwater, rivers, lakes and glaciers.

55. Land runoff. Values ​​characterizing the runoff. Runoff factors

The flow of rain and melt water in small streams down the slopes is called planar or slope drain. Slope runoff jets collect in streams and rivers, forming run-of-river, or linear, called river , stock . Groundwater flows into rivers as ground or underground runoff.

Full river flow R formed from the surface S and underground U:R=S+U . (see Table 1). Total river runoff is 38800 km3, surface runoff is 26900 km3, groundwater runoff is 11900 km3, glacial runoff (2500-3000 km3) and groundwater runoff directly into the seas along the coastline is 2000-4000 km3.

Table 1 - Land water balance without polar glaciers

Surface runoff depends on the weather. It is unstable, temporary, feeds the soil poorly, often needs regulation (ponds, reservoirs).

ground runoff occurs in the soil. During the wet season, the ground receives excess water from the surface and in the rivers, and during the dry months, groundwater feeds the rivers. They ensure the constancy of the flow of water in the rivers and the normal water regime of the soil.

The total volume and ratio of surface and underground runoff varies by zone and region. In some parts of the continents there are many rivers and they are full-flowing, the density of the river network is large, in others the river network is rare, the rivers are shallow or dry up altogether.

The density of the river network and the high water content of rivers are a function of the runoff or water balance of the territory. The flow as a whole is determined by the physical and geographical conditions of the area, on which the hydrological and geographical method of studying land waters is based.

Values ​​characterizing the runoff. Land runoff is measured by the following quantities: runoff layer, runoff modulus, runoff coefficient and runoff volume.

The runoff is most clearly expressed layer which is measured in mm. For example, on the Kola Peninsula, the runoff layer is 382 mm.

Drain module- the amount of water in liters flowing from 1 km 2 per second. For example, in the Neva basin, the runoff module is 9, on the Kola Peninsula - 8, and in the Lower Volga region - 1 l / km 2 x s.

Runoff coefficient- shows what proportion (%) of precipitation flows into rivers (the rest evaporates). For example, on the Kola Peninsula K = 60%, in Kalmykia only 2%. For the entire land mass, the average long-term runoff coefficient (K) is 35%. In other words, 35% of the annual amount of precipitation flows into the seas and oceans.

Flowing water volume measured in cubic kilometers. On the Kola Peninsula, precipitation brings 92.6 km 3 of water per year, and 55.2 km 3 flows down.

The runoff depends on the climate, the nature of the soil cover, topography, vegetation, weathering, the presence of lakes and other factors.

Dependence of runoff on climate. The role of climate in the hydrological regime of the land is enormous: the more precipitation and less evaporation, the greater the runoff, and vice versa. Above 100% humidity, runoff follows rainfall regardless of the amount of evaporation. At less than 100% humidity, runoff decreases following evaporation.

However, the role of climate should not be overestimated to the detriment of other factors. If we recognize climatic factors as decisive, and the rest as insignificant, then we will lose the ability to regulate the flow.

Dependence of runoff on soil cover. Soil and soils absorb and accumulate (accumulate) moisture. The soil cover transforms precipitation into an element of the water regime and serves as a medium in which river runoff is formed. If the infiltration properties and water permeability of soils are low, then little water gets into them, more is spent on evaporation and surface runoff. Well-cultivated soil in a meter layer can store up to 200 mm of precipitation, and then slowly give it to plants and rivers.

Dependence of runoff on relief. It is necessary to distinguish between the value for the runoff of macro-, meso- and microrelief.

Already from insignificant heights, the runoff is greater than from the plains adjacent to them. So, on the Valdai Hills, the runoff module is 12, and on the neighboring plains, only 6 m / km 2 / s. Even more runoff in the mountains. On the northern slope of the Caucasus, it reaches 50, and in the western Transcaucasus, 75 l/km2/s. If on the desert plains Central Asia there is no runoff, then in the Pamir-Alai and Tien Shan it reaches 25 and 50 l / km 2 / s. In general, the hydrological regime and water balance of mountainous countries is different from that of plains.

In the plains, the effect of the meso- and microrelief on the runoff is manifested. They redistribute the runoff and influence its rate. On flat areas of the plains, the runoff is slow, the soils are saturated with moisture, waterlogging is possible. On the slopes, flat runoff turns into a linear one. There are ravines and river valleys. They, in turn, accelerate the flow and drain the area.

Valleys and other depressions in the relief, in which water accumulates, supply the soil with water. This is especially significant in zones of insufficient moisture, where soils and grounds are not soaked and groundwater is formed only when fed from river valleys.

Influence of vegetation on runoff. Plants increase evaporation (transpiration) and thereby drain the area. At the same time, they reduce the heating of the soil and reduce evaporation from it by 50-70%. Forest litter has a high moisture capacity and increased water permeability. It increases the infiltration of precipitation into the ground and thereby regulates runoff. Vegetation contributes to the accumulation of snow and slows its melting, so more water seeps into the ground than from the surface. On the other hand, some of the rain is trapped by the foliage and evaporates before reaching the soil. Vegetation counteracts erosion, slows down runoff and transfers it from surface to underground. Vegetation maintains the humidity of the air and thereby enhances intracontinental moisture cycles and increases the amount of precipitation. It affects the moisture cycle by changing the soil and its water intake properties.

The influence of vegetation is different in different zones. VV Dokuchaev (1892) believed that the steppe forests are reliable and faithful regulators of the water regime of the steppe zone. In the taiga zone, the forests dry up the area through greater evaporation than in the fields. In the steppes, forest belts contribute to the accumulation of moisture by retaining snow and reducing runoff and evaporation from the soil.

The impact on swamp runoff is different in zones of excessive and insufficient moisture. In the forest zone, they are runoff regulators. In the forest-steppe and steppes, their influence is negative, they suck in surface and ground water and evaporate it into the atmosphere.

Weathering crust and runoff. Sand and pebble deposits accumulate water. Often, streams from distant places are filtered through them, for example, in deserts from mountains. On massively crystalline rocks, all surface water drains; on shields, groundwater circulates only in cracks.

Importance of lakes for flow regulation. One of the most powerful flow regulators are large flowing lakes. Large lake-river systems, like the Neva or St. Lawrence, have a very regulated flow and this differs significantly from all other river systems.

Complex of physiographic factors of runoff. All of the above factors act together, influencing one another in an integral system of the geographic envelope, determine gross moistening of the territory . This is the name of that part of atmospheric precipitation, which, with the deduction of rapidly flowing surface runoff, seeps into the soil and accumulates in the soil cover and in the ground, and then is slowly consumed. Obviously, it is the gross moisture that has the greatest biological (plant growth) and agricultural (agriculture) significance. This is the most essential part of the water balance.

General information. The area of ​​the World Ocean is 361 million km/sq. In the northern hemisphere, the World Ocean occupies 61%, and in the southern - 81% of the area of ​​the hemispheres. For convenience Earth depicted in the form of so-called maps of the hemispheres. There are maps of the Northern, Southern, Western and Eastern hemispheres, as well as maps of the hemispheres of the oceans and continents (Fig. 7). In the oceanic hemispheres, 95.5% of the area is occupied by water.

World ocean: structure and history of research. The world ocean is one, it is not interrupted anywhere. From any of its points you can get to any other without crossing the land. According to scientists, the term ocean is borrowed from the Phoenicians and translated from ancient Greek means " great river encircling the earth."

The term "World Ocean" was introduced by the Russian scientist Yu.M. Shokalsky in 1917. In rare cases, the term "oceanosphere" is used instead of the term "World Ocean".

Map of the hemispheres of graphic discoveries, which cover the oceans from the second half of the 15th century to the first half of the 17th century. Great geographical discoveries are associated with the names of X. Columbus, J. Cabot, Vasco da Gama, F. Magellan, J. Drake, A. Tasman, A. Vespucci and others. its outlines, depth, salinity, temperature, etc.

Purposeful scientific research of the World Ocean began in the 17th century and is associated with the names of J. Cook, I. Krusenstern, Yu. Lisyansky, F. Bellingshausen, N. Lazarev, S. Makarov and others. ship Challenger. The results obtained by the Challenger expedition laid the foundation for a new science - oceanography.

In the 20th century, the study of the World Ocean is carried out on the basis of international cooperation. Since 1920, work has been underway to measure the depths of the oceans. The outstanding French explorer Jean Picard was the first to sink to the bottom in 1960. Mariana Trench. A lot of interesting information about the World Ocean was collected by the team of the famous French explorer Jacques Yves Cousteau. Space observations provide valuable information about the World Ocean.

The structure of the oceans. The World Ocean, as is known, is conditionally divided into separate oceans, seas, bays and straits. Each ocean is separate natural complex, conditioned geographic location, the peculiarity of the geological structure and the bioorganisms inhabiting it.

The World Ocean in 1650 was first divided by the Dutch scientist B. Varenius into 5 parts, which are currently approved by the International Oceanographic Committee. As part of the World Ocean, 69 seas are distinguished, including 2 on land (Caspian and Aral).

Geological structure. The world ocean consists of large lithospheric plates, which, with the exception of the Pacific, are named after the continents.

River, glacial and biogenic deposits are found at the bottom of the World Ocean. The deposits of active volcanoes, as a rule, are confined to the mid-ocean ridges.

The relief of the bottom of the oceans. The relief of the bottom of the World Ocean, like the land relief, has a complex structure. The bottom of the World Ocean is usually separated from the land by a continental shelf, or shelf. At the bottom of the World Ocean, as well as on land, there are plains, mountain ranges, plateau-like elevations, canyons and depressions. Deep-sea depressions are a landmark of the World Ocean that cannot be found on land.

The mid-ocean ridges, together with the spurs, form a continuous single chain of mountains with a length of 60,000 km. The waters of the land are divided between five basins: the Pacific, Atlantic, Indian, Arctic and Inner closed. For example, rivers flowing into the Pacific Ocean or its constituent seas are called the rivers of the Pacific Basin, and so on.

A. Soatov, A. Abdulkasymov, M. Mirakmalov "Physical geography of continents and oceans" Publishing and printing art house "O`qituvchi" Tashkent-2013

The hydrosphere is the shell of the Earth, which is formed by oceans, seas, surface water bodies, snow, ice, rivers, temporary water flows, water vapor, clouds. The shell, composed of reservoirs and rivers, oceans has a discontinuous character. The underground hydrosphere is formed by underground currents, groundwater, artesian basins.

The hydrosphere has a volume equal to 1,533,000,000 cubic kilometers. Water covers three fourths of the Earth's surface. Seventy-one percent of the Earth's surface is covered by seas and oceans.

The huge water area largely determines the water and thermal regimes on the planet, since water has a high heat capacity, it has a large energy potential. Water plays an important role in the formation of the soil, the appearance of the landscape. The waters of the oceans differ in chemical composition; water is practically never found in distilled form.

Oceans and seas

The world ocean is a body of water that washes the continents, it makes up more than 96 percent of the total volume of the earth's hydrosphere. Two layers of the water mass of the world's oceans have different temperatures, which ultimately determines the temperature regime of the Earth. The world's oceans accumulate the energy of the sun, and when cooled, part of the heat is transferred to the atmosphere. That is, the thermoregulation of the Earth is largely due to the nature of the hydrosphere. The world ocean includes four oceans: Indian, Pacific, Arctic, Atlantic. Some scientists single out the Southern Ocean, which surrounds Antarctica.

The world ocean is distinguished by the heterogeneity of water masses, which, located in a certain place, acquire distinctive characteristics. The bottom, intermediate, surface and subsurface layers are distinguished vertically in the ocean. The bottom mass has the largest volume, it is also the coldest.

Sea - part of the ocean that extends into the mainland or adjacent to it. The sea differs in its features from the rest of the ocean. The basins of the seas develop their own hydrological regime.

The seas are divided into internal (for example, the Black, Baltic), inter-island (in the Indo-Malay archipelago) and marginal (seas of the Arctic). Among the seas, inland (White Sea), intercontinental (Mediterranean) are distinguished.

Rivers, lakes and swamps

An important component of the Earth's hydrosphere is rivers, they contain 0.0002 percent of all water reserves, 0.005 percent of fresh water. Rivers are an important natural reservoir of water, which is used for drinking, industry, Agriculture. Rivers are a source of irrigation, water supply, watering. Rivers are fed by snow cover, groundwater and rainwater.

Lakes occur when there is excess moisture and in the presence of basins. Basins can be of tectonic, glacial-tectonic, volcanic, cirque origin. Thermokarst lakes are common in permafrost regions, floodplain lakes are often found in river floodplains. The regime of lakes is determined by whether the river carries water out of the lake or not. Lakes can be endorheic, flowing, represent a common lake-river system with a river.

Swamps are common on the plains in conditions of waterlogging. The lowlands are fed by soils, the upland ones are fed by precipitation, the transitional ones are fed by soils and precipitation.

The groundwater

Groundwater is located at different depths in the form of aquifers in the rocks of the earth's crust. Groundwater lies closer to the surface of the earth, groundwater is located in deeper layers. Of greatest interest are mineral and thermal waters.

Clouds and water vapor

Water vapor condensate forms clouds. If the cloud has a mixed composition, that is, it includes ice and water crystals, then they become a source of precipitation.

Glaciers

All components of the hydrosphere have their own special role in the global processes of energy exchange, global moisture circulation, and affect many life-forming processes on Earth.

Water is the simplest chemical compound of hydrogen and oxygen, but ocean water is a universal homogeneous ionized solution, which includes 75 chemical elements. These are solid mineral substances (salts), gases, as well as suspensions of organic and inorganic origin.

Vola has many different physical and chemical properties. First of all, they depend on the table of contents and temperature environment. Let's give brief description some of them.

Water is a solvent. Since water is a solvent, it can be judged that all waters are gas-salt solutions of various chemical composition and various concentrations.

Salinity of ocean, sea and river water

Salinity of sea water(Table 1). The concentration of substances dissolved in water is characterized by salinity which is measured in ppm (% o), i.e., in grams of a substance per 1 kg of water.

Table 1. Salt content in sea and river water (in % of the total mass of salts)

Basic connections	Sea water	river water
Chlorides (NaCI, MgCb)
Sulphates (MgS0 4, CaS0 4, K 2 S0 4)
Carbonates (CaCOd)
Compounds of nitrogen, phosphorus, silicon, organic and other substances

Lines on a map connecting points of equal salinity are called isohalines.

Salinity fresh water (see Table 1) is on average 0.146% o, and marine - on average 35 %about. Salts dissolved in water give it a bitter-salty taste.

About 27 out of 35 grams is sodium chloride (table salt), so the water is salty. Magnesium salts give it a bitter taste.

Since the water in the oceans was formed from hot saline solutions of the earth's interior and gases, its salinity was primordial. There is reason to believe that at the first stages of the formation of the ocean, its waters did not differ much from river waters in terms of salt composition. Differences were outlined and began to intensify after the transformation of rocks as a result of their weathering, as well as the development of the biosphere. The modern salt composition of the ocean, as fossil remains show, was formed no later than the Proterozoic.

In addition to chlorides, sulfites and carbonates, almost all known on Earth chemical elements, including precious metals. However, the content of most elements in sea water is negligible, for example, only 0.008 mg of gold in a cubic meter of water was detected, and the presence of tin and cobalt is indicated by their presence in the blood of marine animals and in bottom sediments.

Salinity of ocean waters- the value is not constant (Fig. 1). It depends on the climate (the ratio of precipitation and evaporation from the surface of the ocean), the formation or melting of ice, sea currents, near the continents - on the influx of fresh water. river waters.

Rice. 1. Dependence of water salinity on latitude

In the open ocean, salinity ranges from 32-38%; in the outskirts and mediterranean seas its fluctuations are much greater.

The salinity of waters down to a depth of 200 m is especially strongly affected by the amount of precipitation and evaporation. Based on this, we can say that the salinity of sea water is subject to the law of zoning.

In the equatorial and subequatorial regions, salinity is 34% c, because the amount of precipitation is greater than the water spent on evaporation. In tropical and subtropical latitudes - 37, since there is little precipitation, and evaporation is high. In temperate latitudes - 35% o. The lowest salinity of sea water is observed in the subpolar and polar regions - only 32, since the amount of precipitation exceeds evaporation.

Sea currents, river runoff, and icebergs disrupt the zonal pattern of salinity. For example, in the temperate latitudes of the Northern Hemisphere, the salinity of water is greater near the western coasts of the continents, where more saline subtropical waters are brought with the help of currents, and the salinity of water is lower near the eastern coasts, where cold currents bring less saline water.

Seasonal changes in water salinity occur in subpolar latitudes: in autumn, due to the formation of ice and a decrease in the strength of river runoff, salinity increases, and in spring and summer, due to ice melting and increased river runoff, salinity decreases. Around Greenland and Antarctica, salinity decreases during the summer as a result of the melting of nearby icebergs and glaciers.

The most saline of all oceans is the Atlantic Ocean, the waters of the Arctic Ocean have the lowest salinity (especially off the Asian coast, near the mouths of Siberian rivers - less than 10% o).

Among the parts of the ocean - seas and bays - the maximum salinity is observed in areas bounded by deserts, for example, in the Red Sea - 42% c, in the Persian Gulf - 39% c.

Its density, electrical conductivity, ice formation and many other properties depend on the salinity of water.

The gas composition of ocean water

In addition to various salts, various gases are dissolved in the waters of the World Ocean: nitrogen, oxygen, carbon dioxide, hydrogen sulfide, etc. As in the atmosphere, oxygen and nitrogen predominate in ocean waters, but in slightly different proportions (for example, the total amount of free oxygen in the ocean 7480 billion tons, which is 158 times less than in the atmosphere). Despite the fact that gases occupy a relatively small place in water, this is enough to influence organic life and various biological processes.

The amount of gases is determined by the temperature and salinity of water: the higher the temperature and salinity, the lower the solubility of gases and the lower their content in water.

So, for example, at 25 ° C, up to 4.9 cm / l of oxygen and 9.1 cm 3 / l of nitrogen can dissolve in water, at 5 ° C - 7.1 and 12.7 cm 3 / l, respectively. Two important consequences follow from this: 1) the oxygen content in the surface waters of the ocean is much higher in temperate and especially polar latitudes than in low latitudes (subtropical and tropical), which affects the development of organic life - the richness of the first and the relative poverty of the second waters; 2) in the same latitudes, the oxygen content in ocean waters is higher in winter than in summer.

Daily changes in the gas composition of water associated with temperature fluctuations are small.

The presence of oxygen in ocean water contributes to the development of organic life in it and the oxidation of organic and mineral products. The main source of oxygen in ocean water is phytoplankton, called the "lungs of the planet." Oxygen is mainly consumed for the respiration of plants and animals in the upper layers of sea waters and for the oxidation of various substances. In the depth interval of 600-2000 m, there is a layer oxygen minimum. A small amount of oxygen is combined with a high content of carbon dioxide. The reason is the decomposition in this water layer of the bulk of the organic matter coming from above and the intensive dissolution of biogenic carbonate. Both processes require free oxygen.

The amount of nitrogen in sea water is much less than in the atmosphere. This gas mainly enters the water from the air during the breakdown of organic matter, but is also produced during the respiration of marine organisms and their decomposition.

In the water column, in deep stagnant basins, as a result of the vital activity of organisms, hydrogen sulfide is formed, which is toxic and inhibits the biological productivity of water.

Heat capacity of ocean waters

Water is one of the most heat-intensive bodies in nature. The heat capacity of only a ten meter layer of the ocean is four times greater than the heat capacity of the entire atmosphere, and a 1 cm layer of water absorbs 94% of the solar heat entering its surface (Fig. 2). Due to this circumstance, the ocean slowly heats up and slowly releases heat. Due to the high heat capacity, all water bodies are powerful heat accumulators. Cooling, the water gradually releases its heat into the atmosphere. Therefore, the World Ocean performs the function thermostat our planet.

Rice. 2. Dependence of heat capacity of water on temperature

Ice and especially snow have the lowest thermal conductivity. As a result, ice protects the water on the surface of the reservoir from hypothermia, and snow protects the soil and winter crops from freezing.

Heat of evaporation water - 597 cal / g, and melting heat - 79.4 cal / g - these properties are very important for living organisms.

Ocean water temperature

An indicator of the thermal state of the ocean is temperature.

Average temperature of ocean waters- 4 °C.

Despite the fact that the surface layer of the ocean acts as the Earth's temperature regulator, in turn, the temperature of sea waters depends on heat balance(incoming and outgoing heat). The heat input is made up of , and the flow rate is made up of the costs of water evaporation and turbulent heat exchange with the atmosphere. Despite the fact that the proportion of heat spent on turbulent heat transfer is not large, its significance is enormous. It is with its help that the planetary redistribution of heat occurs through the atmosphere.

On the surface, the temperature of ocean waters ranges from -2 ° C (freezing temperature) to 29 ° C in the open ocean (35.6 ° C in the Persian Gulf). The average annual temperature of the surface waters of the World Ocean is 17.4°C, and in the Northern Hemisphere it is about 3°C ​​higher than in the Southern Hemisphere. The highest temperature of surface ocean waters in the Northern Hemisphere is in August, and the lowest is in February. In the Southern Hemisphere, the opposite is true.

Since it has thermal relationships with the atmosphere, the temperature of surface waters, like air temperature, depends on the latitude of the area, i.e., it is subject to the zonality law (Table 2). Zoning is expressed in a gradual decrease in water temperature from the equator to the poles.

In tropical and temperate latitudes, water temperature mainly depends on sea currents. So, due to warm currents in tropical latitudes in the west of the oceans, temperatures are 5-7 ° C higher than in the east. However, in the Northern Hemisphere, due to warm currents in the east of the oceans, temperatures are positive all year round, and in the west, due to cold currents, the water freezes in winter. In high latitudes, the temperature during the polar day is about 0 °C, and during the polar night under the ice it is about -1.5 (-1.7) °C. Here, the water temperature is mainly affected by ice phenomena. In autumn, heat is released, softening the temperature of air and water, and in spring, heat is spent on melting.

Table 2. Average annual temperatures of the surface waters of the oceans

	Average annual temperature, "C			Average annual temperature, °C
	North hemisphere	Southern Hemisphere		North hemisphere	Southern Hemisphere

The coldest of all oceans- Arctic, and the warmest- The Pacific Ocean, since its main area is located in the equatorial-tropical latitudes (the average annual temperature of the water surface is -19.1 ° C).

Significant effect on temperature ocean water the climate of the surrounding territories, as well as the season, since the solar heat, which heats the upper layer of the oceans, depends on it. The highest water temperature in the Northern Hemisphere is observed in August, the lowest - in February, and in the Southern - vice versa. Daily fluctuations in sea water temperature at all latitudes are about 1 °C, the largest values ​​of annual temperature fluctuations are observed in subtropical latitudes - 8-10 °C.

The temperature of ocean water also changes with depth. It decreases and already at a depth of 1000 m almost everywhere (on average) below 5.0 °C. At a depth of 2000 m, the water temperature levels off, dropping to 2.0-3.0 ° C, and in polar latitudes - up to tenths of a degree above zero, after which it either drops very slowly or even rises slightly. For example, in the rift zones of the ocean, where at great depths there are powerful outlets of underground hot water under high pressure, with temperatures up to 250-300 °C. In general, two main layers of water are distinguished vertically in the World Ocean: warm superficial and powerful cold extending to the bottom. Between them is a transitional temperature jump layer, or main thermal clip, a sharp decrease in temperature occurs within it.

This picture of the vertical distribution of water temperature in the ocean is disturbed at high latitudes, where at a depth of 300–800 m there is a layer of warmer and saltier water that came from temperate latitudes (Table 3).

Table 3. Average values ​​of ocean water temperature, °C

	Depth, m
equatorial
tropical
Polar

Change in the volume of water with a change in temperature

A sudden increase in the volume of water when freezing is a peculiar property of water. With a sharp decrease in temperature and its transition through the zero mark, a sharp increase in the volume of ice occurs. As the volume increases, the ice becomes lighter and floats to the surface, becoming less dense. Ice protects the deep layers of water from freezing, as it is a poor conductor of heat. The volume of ice increases by more than 10% compared to the initial volume of water. When heated, a process occurs that is the opposite of expansion - compression.

Density of water

Temperature and salinity are the main factors that determine the density of water.

For sea water, the lower the temperature and the higher the salinity, the greater the density of the water (Fig. 3). So, at a salinity of 35% o and a temperature of 0 ° C, the density of sea water is 1.02813 g / cm 3 (the mass of each cubic meter of such sea water is 28.13 kg more than the corresponding volume of distilled water). The temperature of sea water of the highest density is not +4 °C, as in fresh water, but negative (-2.47 °C at a salinity of 30% c and -3.52 °C at a salinity of 35%o

Rice. 3. Relationship between the density of sea water and its salinity and temperature

Due to the increase in salinity, the density of water increases from the equator to the tropics, and as a result of a decrease in temperature, from temperate latitudes to the Arctic Circles. In winter, the polar waters sink and move in the bottom layers towards the equator, so the deep waters of the World Ocean are generally cold, but enriched with oxygen.

The dependence of water density on pressure was also revealed (Fig. 4).

Rice. 4. Dependence of the density of the sea water (A "= 35% o) on pressure at various temperatures

The ability of water to self-purify

This is an important property of water. In the process of evaporation, water passes through the soil, which, in turn, is a natural filter. However, if the pollution limit is violated, the self-cleaning process is violated.

Color and transparency depend on the reflection, absorption and scattering of sunlight, as well as on the presence of suspended particles of organic and mineral origin. In the open part, the color of the ocean is blue, near the coast, where there are a lot of suspensions, it is greenish, yellow, brown.

In the open part of the ocean, water transparency is higher than near the coast. In the Sargasso Sea, the water transparency is up to 67 m. During the development of plankton, the transparency decreases.

In the seas, such a phenomenon as glow of the sea (bioluminescence). Glow in sea water living organisms containing phosphorus, primarily such as protozoa (night light, etc.), bacteria, jellyfish, worms, fish. Presumably, the glow serves to scare away predators, to search for food, or to attract individuals of the opposite sex in the dark. The glow helps fishing boats find schools of fish in sea water.

Sound conductivity - acoustic property of water. Found in the oceans sound-diffusing mine and underwater "sound channel", possessing sonic superconductivity. The sound-diffusing layer rises at night and falls during the day. It is used by submariners to dampen submarine engine noise, and by fishing boats to detect schools of fish. "Sound
signal" is used for short-term forecasting of tsunami waves, in underwater navigation for ultra-long-range transmission of acoustic signals.

Electrical conductivity sea ​​water is high, it is directly proportional to salinity and temperature.

natural radioactivity sea ​​water is small. But many animals and plants have the ability to concentrate radioactive isotopes, so the seafood catch is tested for radioactivity.

Mobility is a characteristic property of liquid water. Under the influence of gravity, under the influence of wind, attraction by the Moon and the Sun and other factors, water moves. When moving, the water is mixed, which allows even distribution of waters of different salinity, chemical composition and temperature.

Natural complexes in the oceans are less studied than on land. However, it is well known that in the World Ocean, as well as on land, the law of zoning operates. Along with latitudinal zonality, deep zonality is also represented in the World Ocean. Latitudinal zones of the World Ocean Equatorial and tropical zones are found in three oceans: Pacific, Atlantic and Indian. The waters of these latitudes are characterized by high temperature, at the equator with […]

The oceans are in constant motion. In addition to waves, the calm of the waters is disturbed by currents, ebbs and flows. All these are different types of water movement in the oceans. Wind waves It is difficult to imagine an absolutely calm expanse of the ocean. Calm - complete calm and the absence of waves on its surface - a rarity. Even in calm and clear weather, ripples can be seen on the surface of the water. And this […]

About 71% of the Earth's surface is covered by ocean waters. The oceans are the largest part of the hydrosphere. The ocean and its parts The World Ocean is the name given to the entire continuous water space of the Earth. The surface area of ​​the World Ocean is 361 million square kilometers, but its waters make up only 1/8oo of the volume of our planet. In the World Ocean, separate parts separated by continents are distinguished. These are oceans - vast areas of the single World Ocean, differing in […]

The waters of the oceans are never at rest. Movements occur not only in the surface water masses, but also in the depths, down to the bottom layers. Water particles perform both oscillatory and translational movements, usually combined, but with a noticeable predominance of one of them. Wave movements (or excitement) are predominantly oscillatory movements. They are fluctuations […]

The freezing point of water with average salinity is 1.8°C below 0°. The higher the salinity of water, the lower its freezing point. The formation of ice in the ocean begins with the formation of fresh crystals, which then freeze. Between the crystals are droplets of salt water, which gradually drains, so young ice is more salty than old, desalinated ice. The thickness of the first-year ice reaches 2-2.5 m, and […]

The ocean receives a lot of heat from the Sun - occupying large area, it receives more heat than land. Water has a high heat capacity, so a huge amount of heat accumulates in the ocean. Only the top 10-meter layer of ocean water contains more heat than the entire atmosphere. But the sun's rays heat only the upper layer of water, heat is transferred down from this layer as a result of […]

3/4 of our planet is covered by the oceans, so it looks blue from space. The world ocean is one, although it is strongly dissected. Its area is 361 million km2, the volume of water is 1,338,000,000 km3. The term "World Ocean" was proposed by Shokalsky Yu.M. (1856 - 1940), Russian geographer and oceanographer. The average depth of the ocean is 3700 m, the greatest is 11,022 m (Marian […]

The World Ocean, divided by continents and islands into separate parts, is a single body of water. The boundaries of the oceans, seas and bays are conditional, since there is a constant exchange of water masses between them. The world ocean as a whole has common features of nature and manifestations of similar natural processes. Research of the World Ocean The first Russian round-the-world expedition of 1803-1806. under the command of I.F. Kruzenshtern and […]

Having reached the sea or the ocean, the fragment would like to calmly lie down on the bottom and “think about its future”, but that was not the case. The aquatic environment has its own forms of movement. Waves, attacking the shores, destroy them and deliver large fragments to the bottom, icebergs carry huge blocks that eventually sink to the bottom, undercurrents carry silt, sand and even blocks […]

The temperature of the waters of the World Ocean The salinity of the waters of the World Ocean The properties of the waters of the World Ocean The world ocean makes up 96% of the mass of the entire hydrosphere. This is a huge body of water that occupies 71% of the Earth's surface. It extends in all latitudes and in all climatic zones of the planet. This is a single indivisible body of water, divided by continents into separate oceans. The question of the number of oceans remains open [...]

Ocean currents - the movement of water in a horizontal direction The reason for the formation of ocean currents is the winds constantly blowing on the surface of the planet. Currents are warm and cold. The temperature of the currents in this case is not an absolute value, but depends on the temperature of the surrounding water in the ocean. If the surrounding water is colder than the current, it is warm; if it is warmer, then the current is considered cold. […]

Russian climatologist Alexander Ivanovich Voeikov called the World Ocean the "heating system" of the planet. Really, average temperature water in the ocean + 17 ° C, while the air temperature is only + 14 ° C. The ocean is a kind of heat accumulator on Earth. Water heats up much more slowly due to its low thermal conductivity compared to solid land, but it also consumes heat very slowly, […]

The ocean is a huge pantry of natural resources, which are comparable in their potential to land resources. Mineral resources are divided into resources of the shelf zone and the deep seabed. The resources of the shelf zone are: Ore (iron, copper, nickel, tin, mercury), at a distance of 10-12 km from the coast - oil, gas. The number of oil and gas basins on the shelf is more than 30. Some basins are purely marine […]

The world ocean includes all the seas and oceans of the Earth. It occupies about 70% of the planet's surface, it contains 96% of all water on the planet. The world ocean consists of four oceans: Pacific, Atlantic, Indian and Arctic. The size of the Pacific oceans - 179 million km2, Atlantic - 91.6 million km2 Indian - 76.2 million km2, Arctic - 14.75 […]

Boundless and great oceans. He is incredibly formidable to people in the hours of bad weather. And then it seems that there is no force that could cope with the mighty abyss. Alas! This impression is deceptive. A serious danger threatens the ocean: drop by drop, substances alien to the ocean environment rush into the ocean, poisoning the water and destroying living organisms. So what is the danger looming [...]

The oceans are called the treasury of the planet. And this is no exaggeration. Sea water contains almost all the chemical elements of the periodic table. There are even more treasures in the bowels of the seabed. For centuries, people did not suspect this. Unless in fairy tales the sea king owned untold riches. Mankind has become convinced that the ocean hides huge reserves of completely unfabulous treasures only in […]

Organic life on our planet originated in the ocean environment. Tens of millions of years, all the wealth organic world limited only water sports. And in our days, when the land was inhabited by living organisms a long time ago, species that are hundreds of millions of years old have survived in the ocean. Many secrets still keep the ocean depths. Not a year goes by without biologists reporting the discovery of […]

As a result of the fact that sea water is saturated with salts, its density is slightly higher than that of fresh water. In the open ocean, this density is most often 1.02 - 1.03 g/cm3. The density depends on the temperature and salinity of the water. It grows from the equator to the poles. Its distribution, as it were, follows the geographical distribution of the spinning top temperature. but with the opposite sign. This […]

In the oceans, the same climatic zones are distinguished as on land. Some oceans do not have certain climatic zones. For example, in the Pacific there is no arctic zone. In the oceans, it is possible to distinguish the surface water column, heated solar heat, and cold deep. Into the depths of the ocean thermal energy The sun penetrates due to the mixing of water masses. Most actively stirs […]