Properties of oceanic waters. Are they the same everywhere in the ocean?

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 the climatic conditions and economic activities of people.

Property 1. Temperature

Ocean waters can accumulate heat. Surface water (about 10 cm deep) retains a huge amount of heat. Cooling, the ocean heats the lower layers of the atmosphere, so that the average temperature of the earth's air is +15 ° C. If there were no oceans on our planet, the average temperature would hardly reach -21 ° C. It turns out that due to the ability of the World Ocean to accumulate heat we got a comfortable and cozy planet.

The temperature properties of oceanic waters vary abruptly. The heated surface layer is gradually mixed with deeper waters, as a result of which a sharp temperature drop occurs at a depth of several meters, and then gradually decreases to the very bottom. The deep waters of the World Ocean have approximately the same temperature, measurements below 3,000 meters usually show a +2 to 0 ° C.

As for surface waters, their temperature depends on geographical latitude. The spherical shape of the planet determines the angle of the sun's rays on the surface. Closer to the equator, the sun gives away more heat than the poles. So, for example, the properties of oceanic waters of the Pacific depend directly on the average temperature indexes. The surface layer has the highest average temperature, which is more than +19 ° C. This can not but affect the surrounding climate, and the underwater flora and fauna. This is followed by the Indian Ocean, whose surface waters are on average heated to 17.3 ° C. Then the Atlantic, where this figure is 16.6 ° C. And the lowest average temperatures - in the Arctic Ocean - about +1 ° C.

Property 2. Salinity

What other properties of oceanic waters are studied by modern scientists? No doubt, they are interested in the composition of the sea water. Water in the ocean is a cocktail of dozens of chemical elements, and an important role in it is reserved for salts. The salinity of ocean waters is measured in ppm. Mark it with the symbol "‰". Promille means a thousandth of a number. It is estimated that a liter of oceanic water has an average salinity of 35 .

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

• The amount of precipitation - rain and snow significantly reduce the overall salinity of the ocean;
• The runoff of large and small rivers is the salinity of the oceans washing the continents with a large number of deep-water rivers below;
• Ice formation - this process increases salinity;
• Melting of ice - this process lowers the salinity of water;
• Evaporation of water from the surface of the ocean - the salts do not evaporate together with the waters, and the salinity rises.

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

Interesting fact. The total amount of salt in the World Ocean

Scientists did not agree on the number of chemical elements dissolved in the waters of the oceans. Presumably from 44 to 75 elements. But they calculated that only an astronomical amount of salts dissolved in the World Ocean, approximately 49 quadrillion tons. If all this salt is evaporated and dried, it will cover the surface of the land with a layer 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 mass of the waters of the World Ocean, to the volume occupied. Knowledge of the magnitude of the density is necessary, for example, to maintain the buoyancy of ships.

Both temperature and density are inhomogeneous properties of ocean waters. The average value of the latter is 1,024 g / cm³. This indicator was measured at mean 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. The largest figure will be in the Suez and Persian Gulf. Here it reaches 1.03 g / cm³. In the warm and salt 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 smallest - about 1.018 g / cm³.

The density of fresh water is lower, which is why it is somewhat more difficult to stay on the water in rivers and other fresh water bodies.

Properties 4 and 5. Transparency and color

If you collect sea water in the jar, it will appear transparent. However, as the thickness of the water layer increases, it acquires a bluish or greenish tinge. The change in color is due to the absorption and dispersion of light. In addition, the color of ocean waters is affected by suspended matter of various composition.

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

Transparency of oceanic water indirectly depends on the amount of suspended particles in it. In the field, transparency is determined by the Secchi disk. A flat disc, whose diameter does not exceed 40 cm, is lowered into the water. The depth at which it does not become visible is taken as the indicator of transparency in this region.

Properties 6 and 7. Sound propagation and electrical conductivity

Sound waves can spread under water for thousands of kilometers. The average propagation velocity is 1500 m / s. This indicator for sea water is higher than for fresh water. The sound always deviates a little from the straight line.

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