How does the salinity of ocean waters change. The temperature of the waters of the oceans: what is it, what does it depend on and how is it related to humans? The temperature of the ocean water depends on

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The level of average salinity of the World Ocean is 35 ppm - this figure is most often called in statistics. A slightly more accurate value, without rounding: 34.73 ppm. In practice, this means that about 35 g of salt should be dissolved in each liter of theoretical ocean water. In practice, this value varies quite a lot, since the World Ocean is so huge that the waters in it cannot quickly mix and form a homogeneous in terms of chemical properties space.

The salinity of ocean water depends on several factors. First, it is defined percentage water evaporating from the ocean and precipitation falling into it. If there is a lot of precipitation, the level of local salinity drops, and if there is no precipitation, but the water evaporates intensively, then salinity rises. Therefore, in the tropics, in certain seasons, the salinity of the waters reaches record values ​​for the planet. The most part of the ocean is the Red Sea, its salinity is 43 ppm.

At the same time, even if the salt content on the surface of the sea or ocean fluctuates, usually these changes practically do not affect the deep layers of water. Surface fluctuations rarely exceed 6 ppm. In some areas, the salinity of the water is reduced due to the abundance of fresh rivers flowing into the seas.

The salinity of the Pacific and Atlantic oceans is slightly higher than the rest: it is 34.87 ppm. The Indian Ocean has a salinity of 34.58 ppm. The Arctic Ocean has the lowest salinity, and the reason for this is melting polar ice, which is especially intense in southern hemisphere. The currents of the Arctic Ocean also affect the Indian Ocean, which is why its salinity is lower than that of the Atlantic and Pacific Oceans.

The farther from the poles, the higher the salinity of the ocean, for the same reasons. However, the saltiest latitudes are between 3 and 20 degrees in both directions from the equator, not the equator itself. Sometimes these "bands" are even said to be salinity belts. The reason for this distribution is that the equator is a zone of constant heavy torrential tropical rains that desalinate water.

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Not only salinity changes, but also the temperature of the water in the oceans. Horizontally, the temperature changes from the equator to the poles, but there is also a vertical change in temperature: it decreases towards depth. The reason is that the sun is not able to penetrate the entire water column and heat the waters of the ocean to the very bottom. The surface temperature of the waters varies greatly. Near the equator, it reaches +25-28 degrees Celsius, and near the North Pole it can drop to 0, and sometimes it can be a little lower.

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The area of ​​the World Ocean is approximately 360 million square kilometers. km. This is about 71% of the entire territory of the planet.

1. What determines the salinity of ocean waters?

The world ocean - the main part of the hydro-sphere - is a continuous water shell the globe. The waters of the World Ocean are heterogeneous in composition and differ in salinity, temperature, transparency and other features.

The salinity of water in the ocean depends on the conditions of evaporation of water from the surface and the inflow of fresh water from the surface of the land and with precipitation. Evaporation of water occurs more intensively in equatorial and tropical latitudes and slows down in temperate and subpolar latitudes. If we compare the salinity of the northern and southern seas, we can establish that the water in the southern seas is more salty. The salinity of the waters in the oceans also varies depending on the geographical location, however, in the ocean, water mixing occurs more intensively than in more closed seas, therefore, the difference in the salinity of the ocean water masses will not be too sharp, as in seas. The most saline (more than 37% o) are the waters of the ocean in the tropics.

2. What are the differences in ocean water temperature?

The water temperature in the World Ocean also varies depending on the geographical latitude. In tropical and equatorial latitudes, the water temperature can reach +30 °С and higher, in the polar regions it drops to -2 °С. With more low temperatures ocean water freezes. Seasonal changes in ocean water temperature are more pronounced in temperate climate zone. The average annual temperature of the World Ocean is 3 °C higher than average temperature sushi. This heat is transferred to land with the help of atmospheric air masses.

3. In what areas of the ocean does ice form? How do they affect the nature of the Earth and economic activity human?

The waters of the World Ocean freeze in the arctic, subarctic and partially in temperate latitudes. The resulting ice cover has an impact on the climate of the continents, making it difficult to use cheap sea transport in the north for transporting goods.

4. What is called the water mass? What are the main types of water masses. What water masses are released in the surface layer of the ocean? material from the site

Water masses, by analogy with air masses, are named according to the geographical zone in which they formed. Each water mass (tropical, equatorial, arctic) has its own characteristic properties and differs from the rest in salinity, temperature, transparency and other features. Water masses differ not only depending on the geographical latitudes of their formation, but also depending on the depth. Surface waters are different from deep and bottom waters. There is practically no effect on deep and bottom waters sunlight and warm. Their properties are more constant throughout the world's oceans, in contrast to surface waters, whose properties depend on the amount of heat and light received. There is much more warm water on Earth than cold water. Residents of temperate latitudes spend their New Year holidays with great pleasure on the coasts of those seas and oceans where the water is warm and clean. Sunbathing under the hot sun, swimming in salty and warm water, people restore strength and improve health.

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On this page, material on the topics:

• "The world's oceans are the main part of the hydrosphere" answers
• short message about the oceans
• what masses of water are secreted in the surface layer of the ocean
• transparency of equatorial water masses
• report on the geography of the waters of the oceans

It has long been known that ocean waters cover most of the surface of our planet. They constitute a continuous water shell, which accounts for more than 70% of the entire geographical plane. But few people thought that the properties of ocean waters are unique. They have a huge impact on climatic conditions and economic activities of people.

Property 1. Temperature

Ocean waters can store heat. (about 10 cm deep) retain a huge amount of heat. Cooling, the ocean warms the lower layers of the atmosphere, due to which the average temperature earth air is +15 °С. If there were no oceans on our planet, then the average temperature would hardly reach -21 ° C. It turns out that thanks to the ability of the oceans to accumulate heat, we got a comfortable and cozy planet.

The temperature properties of oceanic waters change abruptly. The heated surface layer gradually mixes with deeper waters, as a result of which a sharp temperature drop occurs at a depth of several meters, and then a gradual decrease to the very bottom. The deep waters of the oceans have approximately the same temperature, measurements below three thousand meters usually show from +2 to 0 ° C.

As for surface waters, their temperature depends on the geographic latitude. The spherical shape of the planet determines the sun's rays to the surface. Closer to the equator, the sun gives off more heat than at the poles. So, for example, the properties of the ocean waters of the Pacific Ocean directly depend on average temperature indicators. The surface layer has the highest average temperature, which is more than +19 °C. This cannot but affect the surrounding climate, and the underwater flora and fauna. This is followed by the surface waters of which, on average, are warmed up to 17.3 ° С. Then the Atlantic, where this figure is 16.6 ° C. And the lowest average temperatures are in the Arctic Ocean - about +1 °С.

Property 2. Salinity

What other properties of ocean waters are being studied by modern scientists? they are interested in the composition sea ​​water. Water in the ocean - a cocktail of dozens chemical elements, and salts play an important role in it. The salinity of ocean waters is measured in ppm. Designate it with the icon "‰". Promille means a thousandth of a number. It is estimated that a liter of ocean water has an average salinity of 35‰.

In the study of the oceans, scientists have repeatedly wondered what are the properties of ocean waters. Are they the same everywhere in the ocean? It turns out that salinity, like the average temperature, is not uniform. The indicator is influenced by a number of factors:

• amount precipitation- rain and snow significantly reduce the overall salinity of the ocean;
• runoff of large and small rivers - the salinity of the oceans washing the continents with a large number of full-flowing rivers is lower;
• ice formation - this process increases salinity;
• melting ice - this process lowers the salinity of the water;
• evaporation of water from the surface of the ocean - salts do not evaporate with the waters, and salinity rises.

It turns out that the different salinity of the oceans is explained by the temperature of surface waters and climatic conditions. The highest average salinity near the water Atlantic Ocean. However, the most salty point - the Red Sea, belongs to the Indian. The Arctic Ocean is characterized by the least indicator. These properties of the oceanic waters of the Arctic Ocean are most strongly felt near the confluence of the full-flowing rivers of Siberia. Here salinity does not exceed 10‰.

Interesting fact. The total amount of salt in the world's oceans

Scientists did not agree on how many chemical elements are dissolved in the waters of the oceans. Presumably from 44 to 75 elements. But they calculated that just an astronomical amount of salt is dissolved in the oceans, about 49 quadrillion tons. If all this salt is evaporated and dried, it will cover the surface of the land with a layer of more than 150 m.

Property 3. Density

The concept of "density" has been studied for a long time. This is the ratio of the mass of matter, in our case the oceans, to the volume occupied. Knowledge of the density value is necessary, for example, to maintain the buoyancy of ships.

Both temperature and density are inhomogeneous properties ocean waters. The average value of the latter is 1.024 g/cm³. This indicator was measured at average values ​​of temperature and salt content. However, in different parts of the World Ocean, the density varies depending on the depth of measurement, the temperature of the site, and its salinity.

Consider, for example, the properties of ocean waters indian ocean, and specifically the change in their density. This figure will be highest in the Suez and Persian Gulf. Here it reaches 1.03 g/cm³. In the warm and salty waters of the northwestern Indian Ocean, the figure drops to 1.024 g/cm³. And in the freshened northeastern part of the ocean and in the Bay of Bengal, where there is a lot of precipitation, the indicator is the lowest - about 1.018 g / cm³.

Density fresh water lower, which is why staying on the water in rivers and other fresh water bodies is somewhat more difficult.

Properties 4 and 5. Transparency and color

If you collect sea water in a jar, it will seem transparent. However, with an increase in the thickness of the water layer, it acquires a bluish or greenish tint. The change in color is due to the absorption and scattering of light. In addition, suspensions of various compositions affect the color of ocean waters.

The bluish color of pure water is the result of weak absorption of the red part of the visible spectrum. At a high concentration of phytoplankton in ocean water, it becomes blue-green or green color. This is due to the fact that phytoplankton absorbs the red part of the spectrum and reflects the green part.

The transparency of ocean water indirectly depends on the amount of suspended particles in it. In the field, transparency is determined with a Secchi disk. A flat disk, the diameter of which does not exceed 40 cm, is lowered into the water. The depth at which it becomes invisible is taken as an indicator of transparency in the area.

Properties 6 and 7. Sound propagation and electrical conductivity

Sound waves can travel thousands of kilometers under water. average speed distribution - 1500 m/s. This indicator for sea water is higher than for fresh water. The sound always deviates slightly from the straight line.

It has a higher electrical conductivity than fresh water. The difference is 4000 times. It depends on the number of ions per unit of water volume.