3. Characteristics of the oceanic aquatic environment.
© Vladimir Kalanov,
"Knowledge is power".
The oceanic environment, that is, sea water, is not just a substance known to us from birth, which is hydrogen oxide H 2 O. Sea water is a solution of a wide variety of substances. Almost all known chemical elements are found in the waters of the World Ocean in the form of various compounds.
What an absurd situation when the decision was simply to drink sea water! How ignorant were all our ancestors and people who are currently suffering from disasters! Let me finish with a few more general reflections. It is all too easy to get supporters of "our cause" by accusing a powerful and external enemy without getting into serious and stern arguments.
Systematically, these accusations are not based on facts, but simply on the sowing of suspicion of doubt, not to mention anything in particular. An extraordinary sea - but dead! For centuries it has been called Sea Fitido, Devil's Sea and Lake Asphalt. The Bible calls it the Salt Sea and the Arab Sea. Many scholars adhere to the idea that the ruins of Sodom and Gomorrah are buried deep in the sea.
Most of all chlorides are dissolved in seawater (88.7%), among which sodium chloride predominates, that is, ordinary table salt NaCl. Sulfates, that is, salts of sulfuric acid, are significantly less in seawater (10.8%). All other substances account for only 0.5% of the total salt composition of seawater.
After sodium salts, magnesium salts are in second place in seawater. This metal is used in the manufacture of light and strong alloys required in mechanical engineering, especially in aircraft construction. Each cubic meter of seawater contains 1.3 kilograms of magnesium. The technology of its extraction from sea water is based on the conversion of its soluble salts into insoluble compounds and their precipitation with lime. The cost of magnesium, obtained directly from sea water, turned out to be significantly lower than the cost of this metal, previously mined from ore materials, in particular, dolomites.
Some of these names are not exactly what is needed for good place... However, every year thousands of people are attracted to this extraordinary body of water, now known as the Dead Sea or the Salt Sea. And how can he be healthy at the same time? The lowest and saltiest seas.
The Dead Sea is located in the northern part of the Great Crevas Valley, geological fault which extends south to East Africa. Jordan River mosque from the north to reach the lowest surface of the planet - approximately 418 meters below sea level. This closed sea is surrounded by mountain ranges - the Judea Hills to the west and the Moab Mountains to the east.
It should be noted that bromine, discovered in 1826 by the French chemist A. Balyar, is not contained in any mineral. Bromine can be obtained only from seawater, where it is contained in a relatively small amount - 65 grams per cubic meter. Bromine is used in medicine as a sedative, as well as in photography and petrochemicals.
But what makes the Dead Sea so salty? Salts - mainly chlorides of magnesium, sodium and calcium - are delivered to the Dead Sea by the waters of the Jordan River and smaller rivers, streams and springs. It is estimated that the Jordan River alone precipitates a huge amount of 850 thousand tons of salt annually. Because of the low altitude of this sea, the water has nowhere to run; its only recourse is evaporation. On a hot summer day, 7 million tons of water evaporate, which explains why the volume of this lake is not increasing. The water evaporates, but the salts and minerals remain.
Thus, it is the saltiest sea in the world, about 30% salinity - several times saltier than the oceans. Since ancient times, people have been intrigued by the unique characteristics of the Dead Sea. The Greek philosopher Aristotle heard that this sea was "so bitter and salty that there was no fish in it." Its salt concentration is higher than usual, making it even easier to swim without any effort. Thus, even those who cannot swim can swim without problems. The Jewish historian Flavius Josephus says that the Roman general Vespasian experienced this phenomenon by throwing his prisoners of war into this sea.
Already at the end of the 20th century, the ocean began to provide 90% of the world production of bromine and 60% of magnesium. Sodium and chlorine are extracted in significant quantities from seawater. As for food (table) salt, people have long been getting it from sea water by evaporation. Marine salt mines are still operating in tropical countries, where salt is obtained directly in shallow areas of the coast, fencing them off from the sea with dams. The technology is not very complicated here. The concentration of table salt in water is higher than that of other salts, and therefore, when evaporated, it first precipitates. The crystals that have settled on the bottom are removed from the so-called mother liquor and washed with fresh water to remove residual magnesium salts, which impart a bitter taste to the salt.
By now, you may be wondering how this body can be dead and still be healthy. Travelers from the medieval era took stories of a barren sea without birds, fish or vegetation. The smelly fumes of the lake were even thought to be deadly. This, of course, promoted the idea of a fetid, dead sea. In fact, due to its high salinity, only simple organisms, such as some resistant bacteria species, survive in this water, and any fish that stops in this sea, dragged out by rivers flowing into it, quickly perishes.
A more advanced technology for extracting salt from seawater is used in numerous salt works in France and Spain, which supply large amounts of salt not only to the European market. For example, one of the new ways to obtain salt is to install special seawater sprays in the salt pans. Water, turned into dust (suspension), has a huge evaporation area and from the smallest drops it evaporates instantly, and only salt falls to the ground.
The sea is unable to support life, but the same cannot be said for the surrounding region. Although much of it is arid, there are small areas that stand out as lush oases, with waterfalls and tropical plants. The region is also considered to be a rich wildlife habitat. There are 24 species of mammals living near the sea, including the wild cat, Arabian wolf and ibex, which are quite common. Fresh water sources provide habitat for many amphibians, reptiles and fish.
Since the Dead Sea is located on one of the main migration routes, more than 90 species of birds have been identified there, such as the black stork and the white stork. The griffin and the Egyptian griffin can also be seen in this region. But how can the Dead Sea be the healthiest body? It is said that in ancient times, people drank from the water, believing that they have healing properties. Obviously this is not recommended these days. It makes more sense, although some say that bathing in salt water detoxifies the body. The therapeutic benefits of the entire region are highly regarded.
The extraction of table salt from sea water will continue to increase, because the deposits of rock salt, like other minerals, will sooner or later be depleted. Currently, about a quarter of all table salt necessary for mankind is mined in the sea, the rest is mined in salt mines.
Iodine is also contained in sea water. But the process of obtaining iodine directly from water would be completely unprofitable. Therefore, iodine is obtained from dried brown algae growing in the ocean.
Low altitude creates an oxygen-rich atmosphere. The high concentration of bromide in the air is said to have a relaxing effect. The black mud, rich in minerals and sulfurous thermal springs along the shores, is used to treat various skin conditions and arthritis problems.
One of the strangest phenomena of the Dead Sea is the release of bitumen, which sometimes appears on the surface in pieces. Bitumen has been described as "the first petroleum product ever used by humans." Some people thought that these pieces of asphalt were released from the Dead Sea bed and rose to the surface due to earthquakes. However, the asphalt is likely to come out through flaps or crevasses mixed with salt rocks and to the bottom of the sea. Then, as these rocks dissolve, the asphalt blocks rise to the surface.
Even gold is found in ocean water, albeit in negligible amounts - 0.00001 grams per cubic meter. There is a well-known attempt by German chemists in the 1930s to extract gold from the waters of the German Sea (as the North Sea is often called in German). However, it was not possible to fill the vaults of the Reichsbank with gold bars: the production costs would have exceeded the cost of the gold itself.
Over the centuries, bitumen has been used in many ways: as a waterproofing agent for boats, in buildings, and even as a repellent. At that time, the Nabataeans, former nomadic people who settled near the Dead Sea, monopolized the bitumen trade in the region. They brought the bitumen to the bank, cut it open, and then took it to Egypt.
The Dead Sea is truly extraordinary. It is no exaggeration to describe it as saltier, lower, more inhospitable and arguably the healthiest sea. This is definitely one of the most interesting seas on the planet. Petroleum-derived bitumen is also known as asphalt. But in many places the word "asphalt" refers to bitumen mixed with mineral aggregates such as sand or gravel commonly used in road surfaces. In this article, we use both "bitumen" and "asphalt" to refer to the raw product.
Some scientists suggest that in the next few decades it may become economically feasible to obtain heavy hydrogen (deuterium) from the sea, and then humanity will be provided with energy for millions of years to come ... But uranium from seawater is already being mined on an industrial scale. Since 1986 on the banks of the inner Sea of Japan the world's first plant for the extraction of uranium from seawater operates. This complex and expensive technology is designed to produce 10 kg of metal per year. To obtain such an amount of uranium, more than 13 million tons of seawater must be filtered and subjected to ion treatment. But the hard-working Japanese do the job. In addition, they know very well what atomic energy is. -)
Historians report that the Dead Sea was part of a busy commercial route. This has been confirmed by the recent discovery of two wooden anchors. These anchors were found on the shores of the Dead Sea, which were once covered with water, next to which was the old port of En Gedi. One of them is estimated to be about 500 years old, making it the oldest anchor already discovered in the region. It is believed that another, around 2000 years old, was made using the most advanced Roman technology of the time.
Unlike metal anchors, wooden anchors often break in seawater. But the lack of oxygen in the Dead Sea and its salinity kept the timber and ropes of these anchors in excellent condition. Where does all this salt come from, especially considering the many freshwater currents like rivers that flow into the oceans? Scientists have discovered several sources of salt.
An indicator of the amount of chemicals dissolved in water is a special characteristic called salinity. Salinity is the mass of all salts, expressed in grams, contained in 1 kg of seawater... Salinity is measured in thousandths, or ppm (‰). On a surface open ocean salinity fluctuations are small: from 32 to 38 ‰. Average surface salinity The world's oceans are about 35 ‰ (more precisely - 34.73 ‰).
One of them is the ground under your feet. When rainwater seeps into soil and rocks, it dissolves small amounts of minerals, including salts and their chemical constituents, and transports them to the sea through streams and rivers. This process is called erosion. Of course, the concentration of salt in fresh water is very low, so we do not feel salt when we drink it.
Another source is minerals that form salt in the earth's crust below the oceans. Water enters the ocean floor through cracks. It overheats and returns to a surface filled with dissolved minerals. Hydrothermal chimneys - some forming geysers in the seabed - displace the resulting chemical soup into the sea.
Atlantic waters and Pacific oceans have salinity slightly above average (34.87 ‰), and the waters of the Indian Ocean - slightly lower (34.58 ‰). Here the freshening effect of the Antarctic ice affects. For comparison, let us point out that the usual salinity of river waters does not exceed 0.15 ‰, which is 230 times less than the surface salinity of seawater.
In the opposite process, with similar results, submarine volcanoes release large amounts of heated rock into the oceans, where they release chemicals into the water. Another source of minerals is wind, which carries particles from land to sea. All these processes cause seawater to contain almost all known elements. However, the main salt component is sodium chloride - common cooking salt. It makes up 85% of dissolved salts and is the main reason that sea water tastes salty.
What keeps salt levels stable? Salts are concentrated in the sea because the water that evaporates from the ocean is practically pure, and therefore the minerals remain in the sea. Thus, it is clear that salts and other minerals are added and removed in proportion. The question arises: where do the salts go?
The least salty in the open ocean are the waters of the polar regions of both hemispheres. This is due to melting continental ice, especially in the Southern Hemisphere, and large volumes of river flows in the Northern Hemisphere.
Salinity increases towards the tropics. The highest concentration of salts is observed not at the equator, but in the latitude bands of 3 ° -20 ° south and north of the equator. These bands are sometimes called salinity belts.
Many salt compounds are absorbed by the bodies of living organisms. For example, coral polyps, molluscs and crustaceans absorb calcium, a component of salt, into their shells and skeletons. Microscopic algae are called silica diatom extracts. Bacteria and other organisms consume dissolved organic matter. When these organisms die or are eaten, the salts and minerals in their bodies end up in the seabed in the form of dead matter or feces.
Many salts that cannot be removed by biochemical processes are discarded in other ways. For example, clays and other soil materials that reach the ocean through rivers, runoff and volcanic sediments can carry certain salts to the seabed. Some salts also stick to rocks. Thus, through a series of processes, most of the salt ends up being added to the seabed.
The fact that in equatorial zone the surface salinity of water is relatively low, due to the fact that the equator is a zone of torrential tropical rains that desalinate the water. Often, in the equatorial region, dense clouds block the ocean from direct sunlight, which reduces the evaporation of water at such moments.
In the marginal and especially inland seas, salinity differs from that of the ocean. For example, in the Red Sea, the surface salinity of water reaches the highest values in the World Ocean - up to 42 ‰. This is simply explained: the Red Sea is in a zone of high evaporation, and it communicates with the ocean through the shallow and narrow Bab-el-Mandeb Strait, and does not receive fresh water from the continent, since not a single river flows into this sea, but rare rains not able to freshen the water in any noticeable way.
Many researchers believe that geophysical processes complete the cycle, although it takes countless ages. The earth's crust is built from giant plates. Some of them are in subduction zones, where one plaque sinks under another, sinks into a warm mantle. Typically, a denser oceanic plate sinks beneath the nearest, lighter continental plate, while simultaneously accepting salt precipitation as if it were a large conveyor belt. Thus, good part crust slowly processed.
The Baltic Sea, extending far into the land, communicates with the ocean through several small and narrow straits, is located in the temperate zone and receives waters of many large rivers and small rivers. Therefore, the Baltic is one of the most freshened basins in the World Ocean. Surface salinity of the central part Baltic Sea is only 6-8 ‰, and in the north, in the shallow Gulf of Bothnia, it even drops to 2-3 ‰).
Earthquakes, volcanoes and valleys are three manifestations of this process. The salinity of the ocean varies from place to place, and sometimes from season to season. Salt waters are found in the Persian Gulf and the Red Sea, where evaporation is very high. Areas of the oceans that receive fresh water from big rivers or rain is abundant, less salty than average. The same applies to seawater, close to the melting ice of the polar regions, which freezes fresh water. On the other hand, when ice forms, the seawater in the vicinity becomes more saline.
Salinity changes with increasing depth... This is due to the movement of subsurface waters, that is, the hydrological regime of a particular basin. For example, in equatorial latitudes Of the Atlantic and Pacific oceans below a depth of 100-150 m layers of very salt water(above 36 ‰), which are formed due to the transfer of more saline tropical waters by deep countercurrents from the western outskirts of the oceans.
Salinity changes sharply only up to depths of about 1500 m. Below this horizon, fluctuations in salinity are almost not observed. At great depths in different oceans, salinity indicators approach each other. Seasonal changes in salinity on the surface of the open ocean are insignificant, no more than 1 ‰.
Experts believe that salinity anomaly is the salinity of water in the Red Sea at a depth of about 2000 m, which reaches 300 ‰.
The main method for determining the salinity of seawater is the titration method. The essence of the method is that a certain amount of silver nitrate (AgNO 3) is added to the water sample, which in combination with sodium chloride of sea water precipitates in the form of silver chloride. Since the ratio of the amount of sodium chloride to other substances dissolved in water is constant, then, by weighing the precipitated silver chloride, it is quite simple to calculate the salinity of the water.
There are also other methods for determining salinity. Since such, for example, indicators as the refraction of light in water, the density and electrical conductivity of water depend on its salinity, then, having determined them, you can measure the salinity of water.
Taking samples of seawater to determine its salinity or other indicators is not an easy task. To do this, use special samplers - bottles, providing sampling from different depths or from different layers of water. This process requires a lot of care and attention from hydrologists.
So, the main processes affecting the salinity of water are the rate of evaporation of water, the intensity of mixing of more saline waters with less saline ones, as well as the frequency and intensity of precipitation. These processes are determined climatic conditions one or another area of the World Ocean.
In addition to these processes, the salinity of sea water is affected by the proximity of melting glaciers and the volume of fresh water brought by rivers.
In general, the percentage of various salts in seawater in all areas of the ocean almost always remains the same. However, in some places, marine organisms have a noticeable effect on the chemical composition of seawater. They use for their nutrition and development many substances dissolved in the sea, although in different quantities. Some substances, such as phosphates and nitrogenous compounds, are consumed especially in large quantities. In areas where there are many marine organisms, the content of these substances in the water decreases slightly. The smallest organisms that make up plankton have a noticeable effect on the chemical processes taking place in seawater. They drift on the surface of the sea or in the near-surface layers of water and, dying off, slowly and continuously fall to the bottom of the ocean.
Salinity of the World Ocean. Current monitoring map(increase) .
What is the total salt content in the oceans? Now the answer to this question is not at all difficult. If we proceed from the fact that the total amount of water in the World Ocean is 1370 million cubic kilometers, and the average concentration of salts in seawater is 35 ‰, that is, 35 g in one liter, it turns out that one cubic kilometer contains about 35 thousand tons salt. Then the amount of salt in the oceans will be expressed by the astronomical figure 4.8 * 10 16 tons (that is, 48 quadrillion tons).
This means that even the active extraction of salts for domestic and industrial needs will not be able to change the composition of seawater. In this respect, the ocean can be considered inexhaustible without exaggeration.
Now it is necessary to answer an equally important question: where is so much salt in the ocean?
For many years, the hypothesis that rivers brought salt to the sea prevailed in science. But this hypothesis, at first glance quite convincing, turned out to be scientifically untenable. It has been established that every second the rivers of our planet carry out about a million tons of water into the ocean, and their annual flow is 37 thousand cubic kilometers. It takes 37 thousand years for the complete renewal of water in the World Ocean - in about this time, it is possible to fill the ocean with river runoff. And if we assume that in the geological history of the Earth there were at least one hundred thousand such periods, and the salt content in river water, in an average approximation, is about 1 gram per liter, then it turns out that in the entire geological history of the Earth about 1, 4 * 10 20 tons of salts. And according to the calculations of scientists, which we have just cited, 4.8 * 10 16 tons of salt are dissolved in the World Ocean, that is, 3 thousand times less. But it's not only that. Chemical composition salts dissolved in river water differ sharply from the composition of sea salt. If sodium and magnesium compounds with chlorine absolutely predominate in seawater (89% of the dry residue after evaporation of water and only 0.3% is calcium carbonate), then in river water calcium carbonate takes the first place - over 60% of the dry residue, and sodium chlorides and magnesium together - only 5.2 percent.
Scientists have only one suggestion: the ocean became salty during its birth. The most ancient animals could not exist in slightly salted, and even more so in freshwater basins. This means that the composition of sea water has not changed since its inception. But where are the carbonates that have been entering the ocean along with river flows over hundreds of millions of years? The only correct answer to this question was given by the founder of biogeochemistry, the great Russian scientist Academician V.I. Vernadsky. He argued that almost all calcium carbonate, as well as silicon salts brought by rivers into the ocean, are immediately extracted from solution by those marine plants and animals that need these minerals for their skeletons, shells and shells. As these living organisms die off, their calcium carbonate (CaCO 3) and silicon salts are deposited on the seabed as organic sediments. So living organisms throughout the entire existence of the World Ocean maintain unchanged the composition of its salts.
And now a few words about one more mineral contained in sea water. We have spent so many words praising the ocean for the many different salts and other substances found in its waters, including deuterium, uranium, and even gold. But we did not mention the main and main mineral that is found in the oceans - plain water. H 2 O... Without this "mineral" there would be nothing on Earth at all: no oceans, no seas, no you and me. We have already had the opportunity to talk about the basic physical properties of water. Therefore, here we will restrict ourselves to only a few remarks.
In the entire history of science, people have not solved all the secrets of this simple enough chemical, the molecule of which consists of three atoms: two hydrogen atoms and one oxygen atom. By the way, modern science claims that hydrogen atoms make up 93% of all atoms in the universe.
And among the mysteries and secrets of water remain, for example, such: why frozen water vapor turns into snowflakes, the shape of which is a surprisingly regular geometric figure, reminiscent of magnificent patterns. And the drawings on the window panes on frosty days? Instead of amorphous snow and ice, we see ice crystals that are lined up in such an amazing way that they look like leaves and branches of some fabulous trees.
Or here's another. Two gaseous substances - oxygen and hydrogen, combining together, turned into a liquid. Many other substances, including solid ones, when combined with hydrogen, become, like hydrogen, gaseous, for example, hydrogen sulfide H 2 S, hydrogen selenide (H 2 Se), or a compound with tellurium (H 2 Te).
It is known that water dissolves many substances well. They say that it dissolves, albeit to a vanishingly small extent, even the glass of the glass into which we poured it.
However, the most important thing to say about water is that water has become the cradle of life. Water, initially dissolving dozens of chemical compounds in itself, that is, becoming sea water, turned into a solution that is unique in terms of the variety of components, which ultimately turned out to be a favorable environment for the emergence and maintenance of organic life.
In the first chapter of this story of ours, we have already noted that it is almost universally accepted. The hypothesis has now turned into a theory of the origin of life, each position of which, according to the authors of this theory, is based on the factual data of cosmogony, astronomy, historical geology, mineralogy, energy, physics, chemistry, including biological chemistry and other sciences.
The first opinion that life originated in the ocean was expressed in 1893 by the German naturalist G. Bunge. He realized that the amazing similarity between blood and seawater in the composition of the salts dissolved in them is not accidental. Later, the theory of the oceanic origin of the mineral composition of blood was developed in detail by the English physiologist McKellum, who confirmed the correctness of this assumption by the results of numerous blood tests of various animals, from invertebrates to mammals.
It turned out that not only blood, but also the entire internal environment of our body shows traces preserved from the long stay of our distant ancestors in sea water.
At present, world science has no doubts about the oceanic origin of life on Earth.
© Vladimir Kalanov,
"Knowledge is power"
The main feature that distinguishes water Oceans from the waters of the land, is their high salinity... The number of grams of substances dissolved in 1 liter of water is called salinity.
Sea water is a solution of 44 chemical elements, but salts play a primary role in it. Table salt gives the water a salty taste, while magnesium salt gives it a bitter taste. Salinity is expressed in ppm (% o). This is a thousandth of a number. In liter ocean water dissolved on average 35 grams of various substances, which means that the salinity will be 35% o.
The amount of salts dissolved in will be approximately 49.2 10 tons. In order to visualize how large this mass is, the following comparison can be made. If all dry sea salt is distributed over the entire surface of the land, then it will be covered with a layer 150 m thick.
The salinity of ocean waters is not the same everywhere. The salinity is influenced by the following processes:
- evaporation of water. In this process, salts with water do not evaporate;
- ice formation;
- loss, lowering salinity;
- ... The salinity of ocean waters near the continents is much less than in the center of the ocean, since the waters desalinate it;
- melting ice.
Processes such as evaporation and ice formation contribute to an increase in salinity, and precipitation, river runoff, and ice melting lower it. Evaporation and precipitation play a major role in changing salinity. Therefore, the salinity of the surface layers of the ocean, as well as temperature, depends on those related to latitude.
