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Is the Mediterranean sea salty or not? Why is the sea salty? What is the easiest way to determine the salinity of the sea?

Rating of seas by salinity

There are about 80 seas on our planet. Of course, the Dead Sea would take first place in the ranking, since its waters are famous for their salinity. The Dead Sea is one of the saltiest bodies of water on Earth, salinity is 300-310 ‰, in some years up to 350 ‰. But scientists call this body of water a lake.

  1. Red Sea with a salinity of 42‰.

The Red Sea is located between the shores of Africa and Asia. The Red Sea, in addition to its salinity and warmth, boasts its transparency. Many tourists love to relax on its shores.

2. The Mediterranean Sea has a salinity of 39.5‰.

The Mediterranean Sea washes the shores of Europe and Africa. In addition to salinity, it can also boast of its warm waters - in summer they warm up to 25 degrees above zero.

3. Aegean Sea with a salinity of 38.5‰.

The waters of this sea with a high concentration of sodium can cause skin irritation. Therefore, after swimming it is better to take a fresh shower. In summer, the water warms up to 24 degrees Celsius. Its waters wash the shores of the Balkan Peninsula, Asia Minor and the island of Crete.

4. Ionian Sea with a salinity of 38 ‰.

This is the densest and saltiest Greek sea. Its waters allow slow swimmers to hone this skill, as the high density will help keep the body afloat. The area of ​​the Ionian Sea is 169 thousand square kilometers. It washes the shores of Southern Italy, Albania and Greece.

5. The Sea of ​​Japan, whose salinity is 35‰

The sea is located between the continent of Eurasia and the Japanese islands. Its waters also wash the island of Sakhalin. The water temperature depends on the geographical location: in the north – 0 -+12 degrees, in the south – 17-26 degrees. The area of ​​the Sea of ​​Japan is more than 1 million square kilometers.

6. Barents Sea with salinity 34.7-35 ‰

This is the marginal sea of ​​the Arctic Ocean. It washes the shores of Russia and Norway.

7. Laptev Sea with a salinity of 34‰.

Area - 662 thousand square kilometers. It is located between the New Siberian Islands and Severnaya Zemlya. The average annual water temperature is 0 degrees Celsius.

8. Chukchi Sea with a salinity of 33‰.

In winter, the salinity of this sea rises to 33‰, while in summer the salinity decreases slightly. The Chukchi Sea has an area of ​​589.6 thousand km². The average temperature in summer is 12 degrees Celsius, and in winter - almost 2 degrees Celsius.

9. White Sea also has high salinity. In the surface layers the figure stopped at 26 percent, but at depth it increases to 31 percent.

10. Laptev Sea. Salinity at the surface is recorded at 28 percent

The sea has a harsh climate with temperatures below 0°C for more than nine months of the year, sparse flora and fauna, and low population along the coast. Most of the time, with the exception of August and September, it is under ice. The salinity of sea water at the surface in the northwestern part of the sea in winter is 34 ‰ (ppm), in the southern part - up to 20-25 ‰, decreasing in summer to 30-32 ‰ and 5-10 ‰, respectively. The salinity of surface waters is strongly influenced by the melting of ice and the runoff of Siberian rivers.

) or PSU (Practical Salinity Units) units of the Practical Salinity Scale.

Content of some elements in sea water
Element Content,
mg/l
Chlorine 19 500
Sodium 10 833
Magnesium 1 311
Sulfur 910
Calcium 412
Potassium 390
Bromine 65
Carbon 20
Strontium 13
Bor 4,5
Fluorine 1,0
Silicon 0,5
Rubidium 0,2
Nitrogen 0,1

Salinity in ppm is the amount of solids in grams dissolved in 1 kg of seawater, provided that all halogens are replaced by an equivalent amount of chlorine, all carbonates are converted to oxides, and organic matter is burned.

In 1978, the practical salinity scale (PSS-78) was introduced and approved by all international oceanographic organizations, in which the measurement of salinity is based on electrical conductivity (conductometry), and not on water evaporation. Oceanographic CTD sounders became widely used in marine research in the 1970s, and since then water salinity has been measured primarily electrically. To check the operation of electrical conductivity cells that are immersed in water, laboratory salt meters are used. In turn, standard seawater is used to check salinity meters. Standard seawater, recommended by the international organization IAPSO for calibrating salinity meters, is produced in the UK by the Ocean Scientific International Limited (OSIL) laboratory from natural seawater. If all measurement standards are met, a salinity measurement accuracy of up to 0.001 PSU can be achieved.

The PSS-78 scale produces numerical results similar to mass fraction measurements, and the differences are noticeable either when measurements with precision better than 0.01 PSU are required or when the salt composition does not correspond to the standard composition of ocean water.

  • Atlantic Ocean - 35.4 ‰ The highest salinity of surface waters in the open ocean is observed in the subtropical zone (up to 37.25 ‰), and the maximum is in the Mediterranean Sea: 39 ‰. In the equatorial zone, where the maximum amount of precipitation is recorded, salinity decreases to 34 ‰. A sharp desalination of water occurs in the estuary areas (for example, at the mouth of La Plata - 18-19 ‰).
  • Indian Ocean - 34.8 ‰. The maximum salinity of surface waters is observed in the Persian Gulf and the Red Sea, where it reaches 40-41 ‰. High salinity (more than 36 ‰) is also observed in the southern tropical zone, especially in the eastern regions, and in the northern hemisphere also in the Arabian Sea. In the neighboring Bay of Bengal, due to the desalination effect of the Ganges runoff with the Brahmaputra and Irrawaddy, the salinity is reduced to 30-34 ‰. The seasonal difference in salinity is significant only in the Antarctic and equatorial zones. In winter, desalinated waters from the northeastern part of the ocean are transported by the monsoon current, forming a tongue of low salinity along 5° N. w. In summer this language disappears.
  • Pacific Ocean - 34.5 ‰. Tropical zones have the highest salinity (up to a maximum of 35.5-35.6 ‰), where intense evaporation is combined with a relatively small amount of precipitation. To the east, under the influence of cold currents, salinity decreases. High precipitation also reduces salinity, especially at the equator and in the westerly circulation zones of temperate and subpolar latitudes.
  • Arctic Ocean - 32 ‰. In the Arctic Ocean there are several layers of water masses. The surface layer has a low temperature (below 0 °C) and low salinity. The latter is explained by the desalination effect of river runoff, melt water and very weak evaporation. Below there is a subsurface layer, colder (up to −1.8 °C) and more saline (up to 34.3 ‰), formed when surface waters mix with the underlying intermediate water layer. The intermediate water layer is Atlantic water coming from the Greenland Sea with a positive temperature and high salinity (more than 37 ‰), spreading to a depth of 750-800 m. Deeper lies the deep water layer, which is formed in winter also in the Greenland Sea, slowly creeping in a single stream from the strait between Greenland and Spitsbergen. The temperature of deep waters is about −0.9 °C, salinity is close to 35 ‰. .

The salinity of ocean waters varies depending on latitude, from the open part of the ocean to the shores. In the surface waters of the oceans, it is lower in the equator region, in polar latitudes.

Name Salinity,
‰

The salinity of the Black Sea is much lower than in the nearby Mediterranean or Red Seas; it is more like a huge fresh lake. High-water rivers flowing into the Black Sea significantly desalinate its water.

The Black Sea is known for the fact that hydrogen sulfide accumulates in it at great depths, so its bottom has not yet been thoroughly studied. And just above the layer of hydrogen sulfide, water accumulates, much saltier than on the surface of the sea.

What factors influence the salinity of the Black Sea?

  • The level of salinity in this sea is affected by:
  • Located in a temperate and subtropical climate.
  • Significant catchment area.
  • The flow of fresh water from rivers flowing into this sea.
  • Distant location of the Mediterranean and Atlantic.
  • The sea is quite deep.
  • Lack of sea tides.

River flow into the Black Sea

The salinity of water in the Black Sea is relatively low, because... it receives huge volumes of fresh water. The largest river that supplies fresh water to the sea is the Danube. Rivers also provide a lot of water:

  1. Dnieper;
  2. Kuban;
  3. Dniester;
  4. Don et al.

Thanks to these rivers, the water level in the Black Sea is significantly higher than the similar water level in the Atlantic, but lower than the average water level in certain areas of the Mediterranean.

But the water temperature and the percentage of salinity in the Black Sea waters are significantly lower than in the Mediterranean Sea. This is due to the climate and the relatively small influx of fresh water into the Mediterranean.

What is salinity?

The water of any sea contains a huge number of metals, salts, alkalis, etc. Scientists calculate its salinity as a percentage or ppm. A liter of water taken for testing is evaporated, after which the remaining substances are studied and evaluated.

Salinity of the Black Sea in percent

This indicator is calculated based on the content of various substances dissolved in water in grams, and is reflected as a percentage of the total mass. The mass of each precipitated substance is multiplied by 100 grams and divided by 100 percent.

Salinity of the Black Sea in ppm

In ppm, the salinity of the sea is calculated not in hundredths, but in thousandths. For example, from specialized literature we know that the salinity of the Black Sea is 17-18 ppm, the average salinity of the World Ocean is 35 ppm, the Red Sea is 42 ppm, etc.

What is the easiest way to determine the salinity of the sea?

There is a relatively simple way to determine salinity; to conduct such a study at home, you will need dishes that are resistant to high temperatures, a heater and a scale where you can weigh substances in milligrams.

The Earth can be confidently called a water planet, because the World Ocean surrounding the land covers 71% of its entire surface. , included in its composition, differ from each other in many ways. Including such a parameter as salinity, which means the amount of salts dissolved in one liter of water under certain conditions. The salinity of sea water is most often measured in “‰” (ppm). Now it won’t be difficult to find out which is the saltiest sea on Earth.

5. Ionian Sea - salinity exceeds 38 ‰

The Ionian Sea is the part of the Mediterranean that washes the shores of southern Italy and Greece. The bottom of the sea is covered with silt, and closer to the shores - with sand and small shell rock. Its area is 169 thousand km², maximum depth is 5,121 m. This is the greatest depth in the entire Mediterranean Sea. Commercial fishing of mackerel, mullet, tuna, and flounder is carried out. The waters of the Ionian Sea are safe and very warm, even in February their temperature does not fall below 14°C, and at the peak of the holiday season, in August, reaches 25.5°C. Among its inhabitants are bottlenose dolphins, huge turtles, and octopuses. And very dangerous sea urchins and white sharks can hardly be found near the coast. Poisonous dragon fish, which can cause an allergic reaction in humans, are more active at night and burrow into the sand during the day.

4. Aegean Sea - salinity from 37 to 40.0 ‰

This semi-enclosed sea has about 20,000 islands and is located in the eastern Mediterranean. The total area is 179 thousand km². Through the straits it is connected to the Marmara, Black and Mediterranean seas. The salinity of its waters is increasing, which is associated with global warming. After swimming, it is recommended to rinse off the sea water, as this can negatively affect the condition of the skin and mucous membrane of the eyes. There is a fishing industry in the Aegean Sea; sponges are actively mined and octopuses are caught. Due to the fact that there is little plankton in this sea, fishing in its waters is gradually declining.

3. Ligurian Sea - salinity 38 ‰

This sea is located in the western part of the Mediterranean. The shores are steep and rocky, but there are sandy beaches. Many small rivers flow into the Ligurian Sea, which originate in the Apennines. On its shores there are such important ports as:

  • Limpia, which is considered the sea gate of Nice.
  • Cruise ports of Savona, La Spezia, with container and bulk terminals.
  • Genoese port, ranking first in terms of trade volume in Italy.

Despite the high salinity of these waters, on the French-Italian coast of the Ligurian Sea there is one of the most famous resort areas in the world - the Riviera.

2. Mediterranean Sea - salinity from 36 to 39.5 ‰

The Mediterranean Sea is a relic of the ancient Tethys Ocean. It is considered one of the largest seas in size, its area is 2.5 million km². Its basin includes the Sea of ​​Azov, Black and Marmara. The salinity of the sea fluctuates significantly, as water with a much lower salinity comes from the Atlantic through the Strait of Gibraltar. The amount of zooplankton in the Mediterranean Sea is relatively small, and as a result there are few different species of fish, as well as marine animals and mammals. But algae are present in large numbers, especially peridinea and diatoms. The bottom fauna is very poor due to yellowish silt, which is not conducive to the development of life. There are 550 species of fish in the Mediterranean Sea, 70 of which are endemic. The most common species are: mackerel, sardine, horse mackerel, mullet, etc. There are also larger “inhabitants” - sharks, rays, tuna. Edible shellfish are common.

1. Red Sea - salinity 41 ‰

The saltiest of all, the Red Sea is located in a tectonic depression, the depth of which can reach 3 km. It is an inland sea of ​​the Indian Ocean. The hot climate, which provokes strong surface evaporation and low precipitation (about 100 mm per year), and the absence of rivers flowing into the sea, leads to a gradual increase in its salinity. Due to the absence of silt and sand, which are abundant in river water, the Red Sea is distinguished by its extraordinary transparency and purity. The water temperature even in winter is +20 °C, and in summer it is much higher.

Despite its salinity, the waters of the Red Sea amaze with the huge number of different species of fish living in it. But ichthyologists believe that only 60% of fish capable of existing at great depths have been discovered. The sea is extremely beautiful, and it has many interesting and sometimes funny inhabitants, but touching them is strictly prohibited. Corals, sponges, jellyfish, as well as sea urchins, moray eels and poisonous sea snakes are potentially extremely dangerous. Any contact with them can result in a burn, significant blood loss or a severe allergic reaction, and sometimes death. 44 species of sharks live in warm sea waters. The most terrible of them is the tiger, which can easily attack a person.

Having examined them separately, it is now easy to conclude which is the saltiest sea. The salinity of the very famous Dead Sea reaches 350 ‰, but in fact, despite its name, it is an endorheic lake that is gradually drying up.

Our planet is covered with water by 70%, of which more than 96% is occupied by oceans. This means that most of the water on Earth is salty. What is water salinity? How is it determined and what does it depend on? Is it possible to use such water on the farm? Let's try to answer these questions.

What is water salinity?

Most of the water on the planet has salinity. It is usually called sea water and is found in oceans, seas and some lakes. The rest is fresh, its amount on Earth is less than 4%. Before you understand what the salinity of water is, you need to understand what salt is.

Salts are complex substances that consist of cations (positively charged ions) of metals and anions (negatively charged ions) of acid bases. Lomonosov defined them as “fragile bodies that can dissolve in water.” There are many substances dissolved in sea water. It contains sulfates, nitrates, phosphates, cations of sodium, magnesium, rubidium, potassium, etc. Together these substances are defined as salts.

So what is water salinity? This is the content of substances dissolved in it. It is measured in parts per thousand - ppm, which are designated by a special symbol - %o. Permille determines the number of grams in one kilogram of water.

What determines the salinity of water?

In different parts of the hydrosphere and even at different times of the year, the salinity of water is not the same. It changes under the influence of several factors:

  • evaporation;
  • ice formation;
  • precipitation;
  • melting ice;
  • river flow;
  • currents.

When water evaporates from the surface of the oceans, salts remain and do not erode. As a result, their concentration increases. The freezing process has a similar effect. Glaciers contain the largest reserve of fresh water on the planet. During their formation, the salinity of the waters of the World Ocean increases.

The melting of glaciers has the opposite effect, reducing the salt content. In addition to them, the source of fresh water is precipitation and rivers flowing into the ocean. The level of salts also depends on the depth and nature of the currents.

Their greatest concentration is on the surface. The closer to the bottom, the less salinity. influence the salt content in a positive direction; cold ones, on the contrary, reduce it.

Salinity of the World Ocean

What is the salinity of sea water? We already know that it is far from the same in different parts of the planet. Its indicators depend on geographic latitudes, climatic features of the area, proximity to river objects, etc.

The average salinity of the waters of the World Ocean is 35 ppm. Cold areas near the Arctic and Antarctic are characterized by lower concentrations of substances. Although in winter, when ice forms, the amount of salts increases.

For the same reason, the least saline ocean is the Arctic Ocean (32%). The Indian Ocean has the highest content. It covers the Red Sea and Persian Gulf region, as well as the southern tropical zone, where salinity is up to 36 ppm.

The Pacific and Atlantic oceans have approximately equal concentrations of substances. Their salinity decreases in the equatorial zone and increases in subtropical and tropical regions. Some are warm and balance each other out. For example, the non-salty Gulf Stream and the salty Labrador Current in the Atlantic Ocean.

Salinity of lakes and seas

Most lakes on the planet are fresh, as they are fed mainly by sediments. This does not mean that there are no salts in them at all, just that their content is extremely low. If the amount of dissolved substances exceeds one ppm, then the lake is considered saline or mineral. The Caspian Sea has a record value (13%). The largest fresh lake is Baikal.

The concentration of salts depends on how the water leaves the lake. Fresh water bodies are flowing, while saltier ones are closed and subject to evaporation. The determining factor is also the rocks on which the lakes were formed. Thus, in the region of the Canadian Shield, rocks are poorly soluble in water, which is why the water bodies there are “clean”.

The seas are connected to the oceans through straits. Their salinity is slightly different and affects the average values ​​of ocean waters. Thus, the concentration of substances in the Mediterranean Sea is 39% and is reflected in the Atlantic. The Red Sea, with an indicator of 41%o, greatly raises the average. The saltiest is the Dead Sea, in which the concentration of substances ranges from 300 to 350%o.

Properties and significance of sea water

Not suitable for economic activity. It is not suitable for drinking or watering plants. However, many organisms have long adapted to life in it. Moreover, they are very sensitive to changes in its salinity level. Based on this, organisms are divided into freshwater and marine.

Thus, many animals and plants that live in the oceans cannot live in the fresh water of rivers and lakes. Edible mussels, crabs, jellyfish, dolphins, whales, sharks and other animals are exclusively marine.

People use fresh water for drinking. Salted water is used for medicinal purposes. Water with sea salt is consumed in small quantities to restore the body. The healing effect comes from swimming and bathing in sea water.