The temperature of the waters of the oceans: what is it, what does it depend on and how is it related to man. How the salinity of ocean waters changes What temperature is optimal for pregnant women

1. What determines the salinity of ocean waters?

The world ocean - the main part of the hydro-sphere - is a continuous water shell of 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. At lower temperatures, ocean water freezes. Seasonal changes in ocean water temperature are more pronounced in the temperate climate zone. The average annual temperature of the World Ocean is 3 °C higher than the average land temperature. 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 human economic activity?

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. Deep and bottom waters are practically not affected by sunlight and heat. Their properties are more constant throughout the world's oceans, unlike surface subsoils, 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

In the open ocean, the water is more transparent than near the shores, since there are more impurities in the water near the shores. Depending on the type of impurities, water may have a different shade. For example, the waters of the Yellow Sea have a yellow hue due to the silt of this color, which enters the sea along with the waters of the rivers flowing into it.

Water warms up more slowly than land and cools down more slowly. Its heat capacity is greater. In warm weather, ocean water accumulates a huge amount of heat and, cooling down in cold weather, gives it away. Therefore, the World Ocean significantly affects the temperature of the land when the winds blow from it to the continents.

With depth, the temperature of the ocean waters drops and already deeper than 200 m it can be near zero or even lower.

The temperature of the upper layers of the waters of the World Ocean, as well as on land, depends on the latitude of the area. It is much warmer at the equator than at the poles. In temperate zones, the water is warmer in summer than in winter. The average temperature of the surface waters of the World Ocean is about +17 °C.

An important property of the ocean is its salinity. In fact, sea water is bitter-salty. Various salts are dissolved in it. Salinity shows how many grams of salts are dissolved in 1 liter of water. Salinity is measured in ppm (‰). The average salinity of the waters of the World Ocean is about 35‰. This means that 35 grams of various salts are dissolved in 1 liter of ocean water.

Many different substances are dissolved in the oceans, but most of all it contains table salt.

The salinity of the ocean waters is not the same everywhere. So it is not affected by the rivers entering the seas. They desalinate nearby waters. Melting ice also makes the water less salty. Currents carry water and affect salinity. Precipitation has a particularly strong effect on salinity. Where there is a lot of rain, the salinity is less. In places where the temperature is high and there is little rainfall, salinity is high, since water evaporates more at high temperatures.

Salinity and temperature affect the density of water. Cold water is heavier than warm water, more salty water is heavier than less salty water. The different density of water causes it to move.

The amount of substances dissolved in water affects its freezing point. The more of them, the lower the temperature at which water freezes. So, on average, ocean water freezes at -2 °C.

Living organisms living in the seas and oceans are adapted to a certain salinity.

Gases are also dissolved in water. So the amount of oxygen in water decreases with increasing temperature. Therefore, in warm waters, the number of living organisms is less than in relatively colder ones. The amount of oxygen also decreases with depth.

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 heats the lower layers of the atmosphere, due to which the average temperature of the earth's air is +15 °C. 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 of sea water. Ocean water is a cocktail of dozens of 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:

the amount of precipitation - rain and snow significantly lower 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 is near the water of the 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 heterogeneous properties of 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 the oceanic waters of the 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.

The density of fresh water is 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. When there is a high concentration of phytoplankton in ocean water, it becomes blue-green or green in 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. The average propagation speed is 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.

Instruction

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 space that is homogeneous in terms of chemical properties.

The salinity of ocean water depends on several factors. First, it is determined by the percentage of 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 the melting of polar ice, which is especially intense in the 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.

What determines the temperature of the world's oceans

Considering why and how the temperature of the water changes, climate and geographical location are of decisive importance here. If the waters are surrounded by endless deserts, like the Red Sea, then they are able to warm up to + 34C. They are even higher in the Persian Gulf - up to +35.6C. Moving away from the equator, warm currents begin to work. At the same time, cold masses are directed towards warm masses. There is a mixing of giant water masses. The wind is also able to mix the surface layers. In this regard, of course, the example of the Pacific Ocean, which occupies almost half of the entire World and a third of the entire planet Earth, is indicative. Thus, in the state of a storm, the wind mixes the waters in the surface layer of the Pacific Ocean in southern latitudes to a depth of 65 meters. Mixing and dissolving, the average temperature of water in the world ocean is +17.5C.

Considering the average statistical temperature of the water of the oceans, we can state the following: the surface layer of the Pacific Ocean is the warmest + 19.4C. The second place belongs to the Indian +17.3C. The temperature of the surface waters of the Atlantic Ocean is +16.5C - the third place. The champion in the coldest water - a little above + 1C - is predictably the Arctic. But, despite the fact that the average temperature of the surface waters of the Pacific Ocean is the highest, due to its huge size, there are areas in it where it can drop to -1C in winter (Bering Strait).

Salinity influence

High salinity is a hallmark of the world's oceans. By this criterion, it many times exceeds the indicators of waters on land. Sea water contains 44 chemical elements, but salt is the largest among them. To understand how much salt is in the oceans, you need to imagine such a picture - a layer of salt, evenly scattered over land, will be equal to a thickness of 150 meters.

The salinity of the oceans can be arranged in this way:

Atlantic is the saltiest - 35.4%;
Indian in the middle - 34.8%.
The average salinity of the Pacific is the lowest - 34.5%.

This directly affects the density. Thus, the average density of water in the Pacific Ocean is also lower than in others.

The maximum salinity of tropical waters is up to 35.5-35.6 ‰ higher than the average of the World Ocean.

Why and how does the salinity of water change? There are several reasons for this difference:

Evaporation;
Ice cover formation;
Decreased salinity during precipitation;
River waters flow into the world's oceans.

Near the continents, at short distances from the coast, the salinity of the waters is not as high as in the center of the ocean, since they are affected by the desalination of river flows and the melting of ice. And the increase in salinity is actively promoted by evaporation and the formation of ice.

For example, the Red Sea has no rivers flowing into it, but there is very high evaporation due to strong solar heating and low rainfall. As a result, salinity is 42%o. And if we take the Baltic Sea into consideration, then its salinity does not exceed 1% o and, in fact, it is very close to the indicators of fresh water. This is explained by the fact that it is located in a climate with very low evaporation and the highest amount of precipitation.

What water temperature is best for swimming

On the shore of any sea it is very difficult to resist the desire to swim. The sea, waves, sand act as tempters. But someone is tempted by the opportunity to dive into a winter hole, and someone will enjoy swimming only at a water temperature of at least +20C. Everything is very individual in this world. But there is also an ordinary average person who will be happy with the usual average bathing in a pond. Normal temperature is considered to be +22 - +24C. It is important to understand that when immersed in water, the human body is affected not only by the temperature of the surrounding liquid, but also by factors such as:

Sun rays and air temperature;
Pressure;
The power of sea waves.

And yet the human body is able to adapt to numerous changes in the external environment. It can either harden or relax due to the process of thermoregulation. Therefore, the statement, there is nothing better than lukewarm water, is not always and not always correct. Very warm waters contribute to the development and reproduction of a huge number of harmful microorganisms and unpleasant infections. Swimming in such conditions is a threat not only for children, but also for adults. Therefore, it is completely reasonable that residents of different continents and regions of habitat have their own comfort zone for swimming. Here we can cite as an example the inhabitants of the Greek coast with a water temperature not lower than +25C or those who live on the shores of the Baltic Sea, where, by definition, it does not exceed +20C.

What temperature is optimal for pregnant women

Expectant mothers, as well as young children, are most suitable for bathing in warm water. Often, sea baths are chosen for this. The recommended temperature during pregnancy should not be lower than + 22C. It is the most natural and safe and does not pose any threat. Nevertheless, it is important for expectant mothers to remember that even if the temperature balance is observed, direct sunlight should be avoided and it is desirable to avoid possible thermal fluctuations. And no matter how much you like being in the arms of warm sea waves, you should not abuse long bathing. It is believed that the optimal duration of water procedures for pregnant women should not be more than 15-20 minutes.

By absorbing a huge amount of heat, the ocean makes life possible on the planet. This reflects its pricelessness and necessity for all life on Earth. The sun in a certain period heats the World Ocean, and in the next period, warm water gradually warms the atmosphere with this heat. Without this process, our planet will plunge into the most severe cold, and life on Earth will perish. Scientists have calculated that left without the heat stored by the world's oceans, the average earth temperature will drop to -18C or -23C, which is 36 degrees lower than usual today.