We remember: What is the World Ocean? What parts is it divided into? What are the main shapes of the ocean floor? How does the temperature of ocean waters change? What are the types of water movement in the ocean? Under the influence of what causes are sea waves, tsunamis, ocean currents, ebbs and flows formed? What are the characteristics of marine plants and animals and how are they distributed in the ocean? What riches of the oceans are used by man? What is the negative human impact on the ocean? How to deal with pollution of the waters of the oceans?
Keywords:expedition ships, drifting stations, submersibles, artificial satellites and spacecraft.
1. Exploring the ocean in the past. The ocean has always amazed people with its expanses, power, mysterious distances. Ancient people tried in their own way to explain incomprehensible phenomena in the ocean. In their imagination, not natural processes arose, but sea spirits, and then deities. For the ancient Greeks, it was Poseidon, and for the Romans, it was Neptune.
At present, sailors of all countries do not forget about their patron Neptune and arrange a holiday in his honor.
If there are not so many unexplored territories left on land, then in the depths of the ocean there are still a lot of unknown and even mysterious things. First of all, people got acquainted with what is happening on the surface of the ocean and in coastal, shallow parts of it.
The first explorers of the ocean were divers for pearls and sea sponges. They dived without any devices and could stay under water for only a few minutes.
2. Modern research of the World Ocean. A lot of time passed before the researchers got heavy hard suits - spacesuits connected by a hose and cable to the ship. In the forties of the XX century, J.I. Cousteau invented scuba gear. This opened the way for a wide range of people to explore the depths of the sea: archaeologists, geologists, oceanologists, and divers (Fig. 110).
Despite the dangers that await researchers in the ocean, its study does not stop.
Ocean exploration is carried out with the help of special expedition ships, drifting stations, artificial Earth satellites, and underwater vehicles. One of them - a bathyscaphe - is called an underwater airship (Fig. 111).
Rice. 111. Bathyscaphe
On the bathyscaphe "Trieste" in 1960, the Swiss scientist Jacques Picard and his assistant descended into the Mariana Trench to a depth of about 10,500 m. Sometimes underwater houses - laboratories are installed at a depth of 10-20 meters.
An important role in the study of the oceans and seas belongs to artificial earth satellites and spacecraft. From satellites, for example, they study sea currents, monitor the warm current of the Gulf Stream, sea waves and ice.
The ocean is studied comprehensively. The properties of water, its movement at different depths, the characteristics of marine organisms and their distribution are clarified, depths are measured, samples of bottom sediments are taken and studied.
If it is necessary to study large areas of the ocean, scientists different countries combine their efforts. Dozens of special vessels, aircraft, underwater vehicles, and artificial Earth satellites are involved in such studies.
The results of the research are of great importance for navigation, fishing, exploration and extraction of minerals.
1. How is the World Ocean studied? 2. What role do artificial earth satellites and spacecraft play in ocean exploration? 3. Why is it necessary to study the ocean? 4* Do you know when the Neptune festival is held and what ritual it is accompanied by?
Incredible Facts
The ocean is full of secrets. People traditionally fear the ocean and prefer to admire it from the shore. There are places in the world's oceans that people are especially afraid of. Planes and ships disappear there without a trace. There are also giant whirlpools, waves and mysterious luminous circles on the water. However, in addition to the well-known Bermuda Triangle, there are several more such frightening places.
Sargasso Sea
Many people confuse the Sargasso Sea with the Bermuda Triangle. The sea is southeast of the triangle. Moreover, there are many who are trying to find the answer to the mysteries of the triangle in this particular sea. However, the sea is in the center of the Atlantic Ocean. There is a certain feature due to which the sea got its name. Ocean currents move clockwise.
However, the sea is a giant whirlpool that lives by its own laws. The water temperature inside the pool is much higher than outside. While staying in this place, people often see wonderful mirages, for example, it may seem that the sun rises both in the east and in the west at the same time.
Richard Sylvester, a scientist at the University of Western Australia, has suggested that the giant whirlpool of the Sargasso Sea is a centrifuge that creates smaller whirlpools that reach the Bermuda Triangle area. Whirlpools are the cause of mini-cyclones in the air. Cyclones support the spiraling movements of water, which is what makes them appear. This may be the cause of accidents in small aircraft.
devil sea
This is the region of the Pacific Ocean around Miyake Island, which is located about 100 kilometers south of Tokyo. This "relative" of the Bermuda Triangle cannot be found on any map, however, sailors prefer to stay away from this sea. A storm there can start quite unexpectedly, and end as well. Whales, dolphins, and even birds do not live in this region. Since the early 1950s, 9 ships have gone missing in this region. The most famous of the incidents is the disappearance of the Kaiyo Maru No. 5, a Japanese research vessel.
This area is also characterized by high seismic activity. The sea floor is constantly moving, volcanic islands appear and disappear. The region is also known for very active cyclonic activity.
Cape of Good Hope
This area off the coast of South Africa is also known as the Cape of Storms. For hundreds of years, many ships have been wrecked in this region. Most of the disasters have been due to bad weather, particularly killer waves. Scientists also call them solitary waves. They are very large, reaching up to 30 meters in height. They are formed by two coherent waves and become one huge wave. They do not change their shape as they move, even if they collide with other similar waves along the way. They can "move" over very long distances without losing their power. Such huge waves create very deep cavities in front of them, the depth of which corresponds to the height of the wave.
There are many other places in the world's oceans where similar waves form, but in this regard, the region near the Cape of Good Hope is extremely dangerous.
Eastern Indian Ocean and Persian Gulf
This area is known for a very spectacular and mysterious phenomenon - giant, luminous and rotating circles on the surface of the water. German oceanologist Kurt Kahle believes that the luminous circles appear as a result of underwater earthquakes, which make plankton glow. This hypothesis has been recently criticized because it fails to explain the logic of the round shape. Modern science also cannot explain it. Moreover, scientists cannot explain the origin of the rays that come from the center of the circles. The UFO version in this case comes to the fore.
Whirlpool Maelstrom
This whirlpool has no planetary significance like the whirlpool in the Sargasso Sea. However, sailors know dozens of chilling stories about this amazing phenomenon. This whirlpool occurs twice a day in the western Norwegian Sea, off the northwest coast of Norway. The word "maelstrom" was popularized by Edgar Allan Poe in the short story "The Fall into the Maelstrom". A whirlpool is a very strong and large body of "swirling" water, which has a significant downward flow of air. The water surface of the cavity in the center of a powerful vortex is tens of meters below the surface of the water in the ocean. The strength of the whirlpool is ten times greater than the strength of the general current.
Oddly enough, but the whirlpool changes its direction to the opposite every 3-4 months. Maelstrom whirlpools can also occur in other areas, including Bermuda Triangle. It is believed that the Maelstrom is a whirlwind that spins counterclockwise in the northern hemisphere and clockwise in the southern, which is explained by the rotation of the planet Earth.
Land covers less than 30% of our planet's surface. The rest is covered by seas and oceans. Dozens of mysteries and amazing natural phenomena are associated with them. And, despite the fact that scientists have successfully explained the causes of these phenomena, they remain magnificent works of nature that amaze the imagination of people. Let's find out about 10 unusual and exciting phenomena associated with the oceans.
Icebergs don't always look perfectly white!
It's no secret that ocean water temperatures vary from place to place. geographical latitudes. At the equator, the surface layer can warm up to +28°C and higher, while in areas close to the poles - no more than +2°C. Therefore, large icebergs can float in the Arctic and Antarctic for decades. And sometimes they turn ... into striped icebergs!
Striped icebergs form when water first thaws and then refreezes. In between, small particles of dirt, minerals, etc. get into it. After freezing, the color of the fresh iceberg layer is different from others. Thanks to this process, many multi-colored stripes can be observed on the surface of the ice block. That is, not all icebergs are white or transparent, as they are shown in the pictures. On some of them we can observe an amazing play of colors and shades. Moreover, the older the iceberg, the more stripes it has. Looking at them, it may seem that nature itself adorned these blocks of ice with a skillful hand.
9. Whirlpool
Whirlpool - a huge funnel with a lower draft, sucking everything that is nearby
The word "whirlpool" seems to deliberately warn people that this phenomenon should be feared. Interestingly, it was first used by the famous writer Edgar Allan Poe. He described it as a "destructive current". In fact, the ocean whirlpool is a powerful funnel with a lower thrust, slowly but surely sucking in everything that is nearby. They are of three types - permanent (always existing in the same place), seasonal (caused by certain climatic conditions) and episodic (occurring, for example, during earthquakes).
In the seas and oceans, whirlpools are most often caused by the collision of tidal or ebb waves with oncoming currents. At the same time, water in them can move at speeds of hundreds of kilometers per hour.
It is interesting: The width of whirlpools sometimes reaches 3-5 kilometers. Not only small yachts and fishing boats, but also large liners can become victims of such phenomena. You may remember the shocking incident when, in 2011, off the coast of Japan, a ship with a hundred passengers on board was pulled into the whirlpool formed after an earthquake.
Previously, people believed in legends that whirlpools would certainly drag them to the very bottom of the ocean. But scientists have debunked such myths.
8. Red tide
The largest Red Tide can be observed in the Gulf of Florida
Waves of saturated bright red and orange hues are an amazingly beautiful natural phenomenon. But enjoying the red tides is too often unhealthy, because they are fraught with no small danger.
Algae blooms (which cause the water to turn scarlet) can be so intense that plants begin to produce all sorts of toxins and chemicals. Some of them dissolve in water, some get into the air. Toxins harm aquatic life, seabirds and even humans.
The largest Red Tide on the planet is observed annually off the coast of the Gulf of Florida in June-July.
7. Brinicle (salty icicle)
Brinicle spreads an ice net across the bottom of the sea, from which not a single living creature can get out
An amazing work of nature - a salty icicle, is something unimaginable. When a brinicle is finally formed, it looks something like a crystal lowered into water. Salty icicles are formed when water from melting ice seeps into the sea. Considering that very low air and water temperatures are needed for the formation of salty icicles, they can only be observed in the cold waters of the Arctic and off the coast of Antarctica.
It is interesting: Brinicles are fraught with great danger to the flora and fauna of the ocean. At the moment of contact with them, starfish, fish and even algae either freeze and freeze, or receive significant cuts.
The generally accepted model for the formation of brinicles was described by oceanographer Silje Martin as early as 1974. For more than 30 years, only scientists could witness this vivid oceanic performance. But in 2011, the formation of a sea icicle was captured on video by a BBC cameraman.
A stream of salty water flowing out of an ice block is so cold that the liquid surrounding it freezes almost instantly. Seconds after a brinicle enters the ocean, a fragile armor of porous ice forms around it. When the critical mass is reached, the icicle falls to the bottom. Then she begins to unravel her cold nets further. Any animal caught in them is doomed to death. In front of the operators, the "killer icicle" sprouted several meters in 3 hours and reached the ocean floor. After that, in some 15 minutes, the brinicle destroyed all marine life that was within a radius of four meters.
6. The longest wave on Earth
Brazilians call the process of formation of the longest wave Pororoca
Weather conditions have a huge impact on ocean waters. It is not surprising that some natural phenomena can be observed only in a certain season with a combination of many factors contributing to them.
So, the longest wave on the planet can be seen in Brazil no more than 2 times a year. At the end of February and then at the beginning of March, a huge volume of water from the Atlantic Ocean rises up the mouth of the Amazon River. When the current of the river collides with the tidal forces of the ocean, the longest wave on Earth is formed. In Brazil, this phenomenon is called Pororoca. The height of the waves formed during this phenomenon sometimes reaches 3.5-4 meters. And you can hear the sound of the wave half an hour before it crashes onto the shore with a roar. Sometimes Pororoka destroys coastal houses or uproots trees.
5. Frosty Flowers
Thousands of amazing frosty flowers in arctic waters
Few people know about the existence of these delicate, charming flowers. Frosty flowers are formed quite rarely - only on young ice in cold weather. sea water. Their formation occurs at low temperatures in calm weather. The diameter of such formations usually does not exceed four centimeters, but they look like crystal copies of real flowers. They contain a lot of salt, which explains the crystallized appearance of frosty flowers.
It is interesting: If millions of these flowers form in a small area of the sea, they begin to “release” salt into the air!
The sea can not only create conditions for life and support it. It changes itself, like a living organism. And frosty flowers are an example of one of the most beautiful pieces of art created by the oceans.
4. Killer waves
Rogue killer waves can reach a height of 25 meters or more. The reasons for their formation are not known for certain.
As a rule, it is not difficult to determine the moment of wave formation. But there are so-called killer waves, which, in fact, appear out of nowhere and show no signs of their approach.
It is interesting: Usually killer waves are found in the open ocean far from land. They can appear even in clear weather in the absence of strong winds. The reasons have not yet been established. Their size is simply colossal. The height of the wandering killer waves can reach 30 meters, and sometimes more!
For a long time, scientists considered wandering waves to be a fiction of sailors, because they did not fit into any existing mathematical models of the occurrence and behavior of waves. The fact is that from the point of view of classical oceanology, a wave with a height of more than 20.7 meters cannot exist in terrestrial conditions. There was also a lack of reliable evidence of their existence. But on January 1, 1995, on the Norwegian oil platform Dropner, located in the North Sea, instruments recorded a wave 25.6 meters high. They called it the Dropner wave. Soon research began within the framework of the MaxWave project. The specialists monitored the Earth's water surface using two radar satellites launched by the European Space Agency. In just 3 weeks, 10 single stray waves over 25 meters high were recorded in the oceans.
After that, scientists were forced to take a fresh look at the cases of the death of huge ships - container ships and supertankers. Rogue waves have been included among the likely causes of these catastrophes. Later it was proved that in 1980 the 300-meter English cargo ship Derbyshire sank off the coast of Japan after colliding with a giant wave that broke through the cargo hatch and flooded the holds. Then 44 people died.
Killer waves are a sailor's nightmare that appears in many stories and legends. They hide something mysterious and sinister. It seems incredible that predicting the appearance of such a wall of water is almost impossible. The thought of killer waves will definitely make you reconsider your relationship with the ocean. It is unlikely that you will continue to believe that in calm weather you can sail on a boat or yacht far from the coast without fear for your life.
3. The meeting point of the Baltic Sea with the North
On the left is the North Sea, on the right is the Baltic. Surprisingly, their waters don't mix.
In the Danish province of Skagen, one can observe an amazing phenomenon that previously caused a lot of controversy among scientists. In a picturesque place, 2 neighboring seas meet - the Baltic and the North. Surprisingly, they do not mix, as if separated by an invisible wall. The color of the water in each sea is different, this allows you to visually determine the border between them.
According to oceanologists, the density of sea waters differs, as does their salinity (it is 1.5 times higher in the North Sea). Because of this, each sea remains on its own side of the "watershed", not mixing with the neighboring one and not yielding to it. In addition to the composition of the water, the boundary is so pronounced due to the opposite currents in the two straits. Running into each other, they form colliding waves.
Interestingly, the meeting of the North Sea with the Baltic Sea is mentioned in religious literature - in the Koran. It is not clear how the ancient Muslims got to the territory of modern Denmark to see this fantastic sight.
2. Bioluminescence
The glow of the ocean in coastal waters is a fantastic sight
The bioluminescence of water is a phenomenon that looks amazing in photographs and is even more spectacular in reality. The glow of the ocean is due to the simplest algae - dinoflagellates, which make up most of the plankton.
A tiny molecule - the substrate luciferin, is oxidized under the influence of the luciferase enzyme and oxygen. The released energy does not turn into heat, but excites the molecules of the substance, which emits photons. The type of luciferin determines the frequency of light, that is, the color of the glow.
It is best to observe the glow of the ocean during the reproduction of unicellular algae (usually - no more than 3 weeks a year). There are so many tiny lights that sea water becomes like milk, however, painted in bright blue. However, one should be careful when admiring the bioluminescence of the sea or ocean: many algae produce toxins that are dangerous to human health. Therefore, during the period of their reproduction and the greatest intensity of the glow, it will still be better to observe a bright tide while on the shore. And definitely at night! It may seem that huge searchlights are hidden under the water, illuminating it from the depths.
1. Phenomenon of the Milky Sea
The glow of the ocean, caused by the phenomenon of bioluminescence, can sometimes be seen even from space!
The Sea of Milk phenomenon is observed in the Indian Ocean, and this is one of the manifestations of the bioluminescence process.
It is interesting: In certain areas of the ocean, ideal conditions are created for the reproduction of bacteria. Then huge volumes of salt water begin to glow and are colored with light blue lights. Sometimes bacteria illuminate such large areas of water that they can be easily seen even from space. Such a spectacle will not leave anyone indifferent!
This phenomenon has been observed for more than a century. The glow of the water was often observed by sailors in antiquity, it made them enthusiastically peer into the depths of the ocean. However, if earlier people could not find an explanation for this phenomenon, then in our time everything is known about its nature. But this does not prevent the glow of water from being a fantastic sight.
Such phenomena show all the beauty and diversity of the majestic oceans. Watching them, you involuntarily catch yourself thinking that human civilization, no matter how advanced it may be, will not be able to create anything like this! After all, people are only temporary guests on this amazing planet. And we must not destroy, but preserve all the splendor of nature for future generations.
The World Ocean, covering 71% of the Earth's surface, strikes with the complexity and variety of processes developing in it.
From the surface to the greatest depths, the waters of the ocean are in continuous motion. These complex movements of water from huge ocean currents to the smallest eddies are excited by tide-forming forces and serve as a manifestation of the interaction of the atmosphere and the ocean.
The water mass of the ocean at low latitudes accumulates heat received from the sun and transfers this heat to high latitudes. The redistribution of heat, in turn, excites certain atmospheric processes. So, in the area of convergence of cold and warm currents powerful cyclones occur in the North Atlantic. They reach Europe and often determine the weather throughout its space up to the Urals.
The living matter of the ocean is very unevenly distributed over the depths. In different regions of the ocean, biomass depends on climatic conditions and the supply of nitrogen and phosphorus salts to surface waters. The ocean is home to a great variety of plants and animals. From bacteria and unicellular green phytoplankton algae to the largest mammals on earth - whales, whose weight reaches 150 tons. All living organisms form a single biological system with their own laws of existence and evolution.
Loose sediments accumulate very slowly at the bottom of the ocean. This is the first stage in the formation of sedimentary rocks. In order for geologists working on land to be able to correctly decipher the geological history of a particular territory, it is necessary to study in detail the modern processes of sedimentation.
As it turned out in recent decades, the earth's crust under the ocean has great mobility. At the bottom of the ocean, mountain ranges, deep rift valleys, and volcanic cones are formed. In a word, the bottom of the ocean "lives" violently, and often there are such strong earthquakes that huge devastating tsunami waves rapidly run across the surface of the ocean.
Trying to explore the nature of the ocean - this grandiose sphere of the earth, scientists are faced with certain difficulties, to overcome which they have to apply the methods of all the main natural sciences: physics, chemistry, mathematics, biology, geology. Oceanology is usually spoken of as a union of various sciences, a federation of sciences united by the subject of study. In this approach to the study of the nature of the ocean, there is a natural desire to penetrate deeper into its secrets and an urgent need to deeply and comprehensively know the characteristic features of its nature.
These tasks are very complex, and they have to be solved by a large team of scientists and specialists. In order to imagine exactly how this is done, consider the three most relevant areas of ocean science:
- ocean-atmosphere interaction;
- the biological structure of the ocean;
- ocean floor geology and its mineral resources.
The long-term tireless work of the oldest Soviet research vessel "Vityaz" has completed. It arrived at the Kaliningrad sea port. The 65th farewell flight, which lasted more than two months, has ended.
Here is the last "traveling" entry in the ship's log of a veteran of our oceanographic fleet, who, in thirty years of voyages, left more than a million miles behind the stern.
In a conversation with a Pravda correspondent, the head of the expedition, Professor A. A. Aksenov, noted that the 65th flight of the Vityaz, like all previous ones, was successful. During complex research in the deep-sea regions of the Mediterranean Sea and the Atlantic Ocean, new scientific data have been obtained that will enrich our knowledge of the life of the sea.
Vityaz will be temporarily based in Kaliningrad. It is assumed that then it will become the base for the creation of the Museum of the World Ocean.
For several years, scientists from many countries have been working on the international project GAAP (Global Atmospheric Process Research Program). The aim of this work is to find a reliable method for weather forecasting. There is no need to explain how important this is. It will be possible to know in advance about drought, floods, downpours, strong winds, heat and cold ...
So far, no one can give such a forecast. What is the main difficulty? It is impossible to accurately describe the processes of interaction between the ocean and the atmosphere with mathematical equations.
Nearly all of the water that falls on land as rain and rain enters the atmosphere from the surface of the ocean. Ocean waters in the tropics become very hot, and currents carry this heat to high latitudes. Over the ocean there are huge whirlwinds - cyclones that determine the weather on land.
The ocean is the kitchen of the weather... But there are very few permanent weather stations in the ocean. These are a few islands and several automatic floating stations.
Scientists are trying to build a mathematical model of the interaction between the ocean and the atmosphere, but it must be real and accurate, and this lacks many data on the state of the atmosphere over the ocean.
The solution was found to be very accurate and continuous measurements from ships, aircraft and meteorological satellites in a small area of the ocean. Such an international experiment called "Tropex" was carried out in the tropical zone of the Atlantic Ocean in 1974, and very important data were obtained for building a mathematical model.
It is necessary to know the whole system of currents in the ocean. Currents carry heat (and cold), nutritious mineral salts necessary for the development of life. A long time ago, sailors began to collect information about the currents. It began in the 15th-16th centuries, when sailing ships took to the open ocean. Nowadays, all sailors know that there are detailed maps of surface currents, and use them. However, in the last 20-30 years, discoveries have been made that have shown how inaccurate current maps are and how complex the overall picture of ocean circulation is.
In the equatorial zone of the Pacific and Atlantic oceans, powerful deep currents were explored, measured and mapped. They are known as the Cromwell Current in the Pacific and the Lomonosov Current in the Atlantic Ocean.
In the west of the Atlantic Ocean, the deep Antilo-Guiana countercurrent was discovered. And under the famous Gulf Stream turned out to be the Counter-Gulf Stream.
In 1970, Soviet scientists conducted a very interesting study. A series of buoy stations have been installed in the tropical zone of the Atlantic Ocean. Currents at various depths were continuously recorded at each station. The measurements lasted half a year, and hydrological surveys were periodically performed in the area of measurements to obtain data on the general pattern of water movement. After processing and summarizing the measurement materials, a very important general pattern emerged. It turns out that the previously existing idea of a relatively uniform nature of the constant trade wind current, which is excited by the north trade winds, does not correspond to reality. There is no such stream, this huge river in liquid banks.
Huge whirlpools, whirlpools, tens and even hundreds of kilometers in size, move in the zone of the trade wind current. The center of such a vortex moves at a speed of about 10 cm/s, but on the periphery of the vortex, the flow velocity is much higher. This discovery of Soviet scientists was later confirmed by American researchers, and in 1973 similar eddies were traced in Soviet expeditions operating in the North Pacific Ocean.
In 1977-1978. A special experiment was set up to study the eddy structure of currents in the area of the Sargasso Sea in the west of the North Atlantic. Over a large area, Soviet and American expeditions continuously measured currents for 15 months. This huge amount of material has not yet been fully analyzed, but the formulation of the problem itself required massive specially designed measurements.
Particular attention to the so-called synoptic eddies in the ocean is due to the fact that it is the eddies that carry the largest share of the current energy. Consequently, their careful study can bring scientists much closer to solving the problem of long-range weather forecasting.
Another most interesting phenomenon associated with ocean currents has been discovered in recent years. To the east and west of the powerful Gulf Stream, very stable so-called rings (rings) were found. Like a river, the Gulf Stream has strong meanders. In some places, the meanders close, and a ring is formed, in which the temperature of the hearth differs sharply at the periphery and in the center. Such rings have also been traced on the periphery of the powerful Kuroshio current in the northwestern part of the Pacific Ocean. Special observations of rings in the Atlantic and Pacific oceans have shown that these formations are very stable, maintaining a significant difference in water temperature on the periphery and inside the ring for 2-3 years.
In 1969, for the first time, special probes were used to continuously measure temperature and salinity at various depths. Prior to this, the temperature was measured with mercury thermometers at several points at different depths, and water was raised from the same depths in bottles. Then the salinity of the water was determined and the salinity and temperature values were plotted on a graph. The depth distribution of these water properties was obtained. Measurements at individual points (discrete) did not even allow us to assume that the water temperature changes with depth as complexly as it was shown by continuous measurements with the probe.
It turned out that the entire water mass from the surface to great depths is divided into thin layers. The difference in temperature between adjacent horizontal layers reaches several tenths of a degree. These layers, from several centimeters to several meters thick, sometimes exist for several hours, sometimes disappear in a few minutes.
The first measurements, made in 1969, seemed to many to be a random phenomenon in the ocean. It cannot be, the skeptics said, that the mighty ocean waves and currents do not mix the water. But in subsequent years, when the sounding of the water column with precise instruments was carried out throughout the ocean, it turned out that the thin-layered structure of the water column was found everywhere and always. The reasons for this phenomenon are not entirely clear. So far, they explain it this way: for one reason or another, numerous fairly clear boundaries appear in the water column, separating layers with different densities. At the boundary of two layers of different density, internal waves very easily arise, which mix the water. In the process of destruction of internal waves, new homogeneous layers arise, and the boundaries of the layers are formed at other depths. So this process is repeated many times, the depth of occurrence and the thickness of layers with sharp boundaries change, but general character the water column remains unchanged.
In 1979, the pilot phase of the International Program for the Study of Global Atmospheric Processes (PGAP) began. Several dozens of ships, automatic observation stations in the ocean, special aircraft and meteorological satellites, all this mass of research facilities is working throughout the entire expanse of the World Ocean. All participants in this experiment work according to a single coordinated program so that, by comparing the materials of the international experiment, it would be possible to build a global model of the state of the atmosphere and ocean.
If we take into account that in addition to the general task - the search for a reliable method of long-term weather forecasting, it is necessary to know a lot of particular facts, then the general task of ocean physics will seem very, very complicated: measurement methods, instruments, the operation of which is based on the use of the most modern electronic circuits, are quite difficult processing of the information received with the obligatory use of a computer; construction of very complex and original mathematical models of processes developing in the water column of the ocean and at the boundary with the atmosphere; setting up extensive experiments in characteristic regions of the ocean. These are the general features of modern research in the field of ocean physics.
Special difficulties arise in the study of living matter in the ocean. Relatively recently, the necessary materials were obtained for a general characterization of the biological structure of the ocean.
Only in 1949 was life discovered at depths of more than 6000 m. Later, the deep-sea fauna - the fauna of the ultraabyssal - turned out to be the most interesting object of special research. At such depths, the conditions of existence are very stable on a geological time scale. Based on the similarity of the ultra-abyssal fauna, it is possible to establish the former connections of individual oceanic depressions and restore the geographical conditions of the geological past. So, for example, comparing the deep-sea fauna of the Caribbean Sea and the Eastern Pacific Ocean, scientists have found that in the geological past there was no Isthmus of Panama.
Somewhat later, a striking discovery was made - a new type of animal, pogonophores, was discovered in the ocean. A thorough study of their anatomy, a systematic classification made up the content of one of the outstanding works in modern biology - A. V. Ivanov's monograph "Pogonophores". These two examples show how difficult it has been to study the distribution of life in the ocean, and even more general patterns functioning of the biological systems of the ocean.
Comparing disparate facts, comparing the biology of the main groups of plants and animals, scientists have come to important conclusions. The total biological production of the World Ocean turned out to be somewhat less than a similar value characterizing the entire land area, despite the fact that the ocean area is 2.5 times larger than the land area. This is due to the fact that the areas of high biological productivity are the periphery of the ocean and the areas of deep water rise. The rest of the ocean is an almost lifeless desert, where only large predators can be found. Separate oases in the ocean desert are only small coral atolls.
Another important finding concerns the general characteristics of food chains in the ocean. The first link in the food chain is unicellular green algae phytoplankton. The next link is zooplankton, then planktivorous fish and predators. Milking animals - benthos, which are also food for fish, are of significant importance.
Reproduction in each link of the food price is such that the produced biomass is 10 times higher than its consumption. In other words, 90% of, for example, phytoplankton dies naturally and only 10% serves as food for zooplankton. It has also been established that zooplankton crustaceans perform vertical diurnal migrations in search of food. More recently, it was possible to detect clumps of bacteria in the diet of zooplankton crustaceans, and this type of food accounted for up to 30% of the total volume. The general result of modern studies of ocean biology is that an approach has been found and the first block mathematical model of the ecological system of the open ocean has been built. This is the first step towards the artificial regulation of ocean biological productivity.
What methods do biologists use in the ocean?
First of all, a variety of fishing gear. Small plankton organisms are caught with special cone nets. As a result of fishing, an average amount of plankton is obtained in weight units per unit volume of water. These nets can catch individual horizons of the water column or "filter" water from a given depth to the surface. Bottom animals are caught by various tools towed along the bottom. Fish and other nekton organisms are caught by mid-depth trawls.
Peculiar methods are used to study the food relationships of various plankton groups. Organisms “tag” with radioactive substances and then determine the amount and rate of grazing in the next link in the food chain.
In recent years, physical methods have been used to indirectly determine the amount of plankton in water. One of these methods is based on the use of a laser beam, which, as it were, probes the surface layer of water in the ocean and provides data on the total amount of phytoplankton. Another physical method is based on the use of the ability of plankton organisms to glow - bioluminescence. A special bathometer-probe is immersed in water, and as it sinks, the intensity of bioluminescence is recorded as an indicator of the amount of plankton. These methods very quickly and completely characterize the distribution of plankton in a variety of sounding points.
An important element in the study of the biological structure of the ocean is chemical research. Content nutrients(mineral salts of nitrogen and phosphorus), dissolved oxygen and a number of other important characteristics of the habitat of organisms are determined by chemical methods. Particularly important are careful chemical definitions when studying highly productive coastal areas - upwelling zones. Here, with regular and strong winds from the shore, there is a strong collapse of water, accompanied by the rise of deep waters and their spread in the shallow area of the shelf. Deep waters contain in dissolved form a significant amount of mineral salts of nitrogen and phosphorus. As a result, phytoplankton flourishes in the upwelling zone and, ultimately, an area of commercial concentrations of fish is formed.
The prediction and registration of the specific nature of the habitat in the upwelling zone is carried out by chemical methods. Thus, in biology, the question of acceptable and applicable methods of research is being solved in our time in a complex way. While widely using traditional methods of biology, researchers are increasingly using the methods of physics and chemistry. The processing of materials, as well as their generalization in the form of optimized models, is carried out using the methods of modern mathematics.
In the field of ocean geology, so many new facts have been obtained over the past 30 years that many traditional ideas have had to be drastically changed.
Just 30 years ago, measuring the depth of the ocean floor was extremely difficult. It was necessary to lower a heavy lot with a load suspended on a long steel cable into the water. At the same time, the results were often erroneous, and the points with measured depths were separated from one another by hundreds of kilometers. Therefore, the idea of the vast expanses of the ocean floor as giant plains dominated.
In 1937, for the first time, a new method of measuring depths was applied, based on the effect of sound signal reflection from the bottom.
The principle of measuring depth with an echo sounder is very simple. A special vibrator mounted in the lower part of the ship's hull emits pulsating acoustic signals. The signals are reflected from the bottom surface and are picked up by the receiving device of the echo sounder. The round-trip time of the signal depends on the depth, and a continuous bottom profile is drawn on the tape as the ship moves. A series of such profiles, separated by relatively small distances, makes it possible to draw lines of equal depths - isobaths on the map and depict the bottom relief.
Depth measurements with an echo sounder have changed scientists' previous ideas about the topography of the ocean floor.
What does it look like?
A strip extending from the shore is called the continental shelf. Depths on the continental shelf usually do not exceed 200-300 m.
In the upper zone of the continental shelf there is a continuous and rapid transformation of the relief. The coast recedes under the onslaught of waves, and at the same time large accumulations of detrital material appear under the water. It is here that large deposits of sand, gravel, pebbles are formed - an excellent building material, crushed and sorted by nature itself. Various spits, embankments, bars, in turn, build up the coast in another place, separate lagoons, block river mouths.
In the tropical zone of the ocean, where the water is very clean and warm, grandiose coral structures grow - coastal and barrier reefs. They stretch for hundreds of kilometers. Coral reefs serve as a refuge for a great variety of organisms and together with them form a complex and extraordinary biological system. In a word, the upper zone of the shelf "lives" with a stormy geological life.
At depths of 100-200 m, geological processes seem to freeze. The relief becomes leveled, there are many bedrock outcrops at the bottom. The destruction of the rocks is very slow.
On the outer edge of the shelf, facing the ocean, the bottom surface slope becomes steeper. Sometimes slopes reach 40-50°. This is the continental slope. Its surface is cut by underwater canyons. Tense, sometimes catastrophic processes take place here. Silt accumulates on the slopes of underwater canyons. At times, the stability of the accumulations is suddenly broken, and a mud stream falls down along the bottom of the canyon.
The mud flow reaches the mouth of the canyon, and here the main mass of sand and large debris, being deposited, forms an alluvial cone - an underwater delta. A turbid flow goes beyond the continental foot. Quite often, separate alluvial fans unite, and a continuous strip of loose sediments of great thickness forms at the continental foot.
53% of the bottom area is occupied by the ocean bed, the area that until recently was considered a plain. In fact, the relief of the ocean floor is quite complex: uplifts of various structures and origins divide it into huge basins. The dimensions of oceanic basins can be estimated from at least one example: the northern and eastern basins of the Pacific Ocean cover an area larger than the entire North America.
A large area of the basins themselves is dominated by a hilly relief, sometimes there are separate seamounts. The height of the mountains of the ocean reaches 5-6 km, and their peaks often rise above the water.
In other areas, the ocean floor is crossed by huge gently sloping swells several hundred kilometers wide. Usually, volcanic islands are located on these shafts. In the Pacific Ocean, for example, there is the Hawaiian Wall, on which there is a chain of islands with active volcanoes and lava lakes.
Volcanic cones rise from the bottom of the ocean in many places. Sometimes the top of the volcano reaches the surface of the water, and then an island appears. Some of these islands are gradually being destroyed and hidden under water.
In the Pacific Ocean, several hundred volcanic cones have been discovered with clear traces of wave action on flat tops, submerged to a depth of 1000-1300 m.
The evolution of volcanoes may be different. Reef-forming corals settle at the top of the volcano. With slow sinking, corals build up a reef, and over time, a ring island is formed - an atoll with a lagoon in the middle. Coral reef growth can take a very long time. Drilling has been carried out on some Pacific atolls to determine the thickness of the coral limestone sequence. It turned out that it reaches 1500. This means that the top of the volcano descended slowly - for about 20 thousand years.
By studying the bottom topography and the geological structure of the ocean's solid crust, scientists have come to some new conclusions. The earth's crust under the ocean floor turned out to be much thinner than on the continents. On the continents, the thickness of the Earth's solid shell - the lithosphere - reaches 50-60 km, and in the ocean it does not exceed 5-7 km.
It also turned out that the lithosphere of land and ocean is different in rock composition. Under a layer of loose rocks - products of the destruction of the land surface lies a powerful granite layer, which is underlain by a basalt layer. There is no granite layer in the ocean, and loose deposits lie directly on the basalts.
Even more important was the discovery of a grandiose system of mountain ranges at the bottom of the ocean. mountain system mid-ocean ridges stretches across all oceans for 80,000 km. In size, underwater ranges are comparable only to the greatest mountains on land, such as the Himalayas. The crests of underwater ridges are usually cut along by deep gorges, which were called rift valleys, or rifts. Their continuation can also be traced on land.
Scientists have realized that the global rift system is a very important phenomenon in the geological development of our entire planet. A period of careful study of the system of rift zones began, and soon such significant data were obtained that there was a sharp change in ideas about the geological history of the Earth.
Now scientists have again turned to the half-forgotten hypothesis of continental drift, expressed by the German scientist A. Wegener at the beginning of the century. A careful comparison of the contours of the continents separated by the Atlantic Ocean was made. At the same time, the geophysicist J. Bullard combined the contours of Europe and North America, Africa and South America not along the coastlines, but along the median line of the continental slope, approximately along the 1000 m isobath. The outlines of both coasts of the ocean coincided so exactly that even inveterate skeptics could not doubt the real huge horizontal movement of the continents.
Particularly convincing were the data obtained during geomagnetic surveys in the area of mid-ocean ridges. It turned out that the erupted basaltic lava gradually shifted to both sides of the crest of the ridge. Thus, direct evidence was obtained of the expansion of the oceans, the spreading earth's crust in the area of the rift and in accordance with this continental drift.
Deep drilling in the ocean, which has been carried out for several years from the American ship Glomar Challenger, has again confirmed the fact of the expansion of the oceans. They even established the average value of the expansion of the Atlantic Ocean - a few centimeters per year.
It was also possible to explain the increased seismicity and volcanism at the periphery of the oceans.
All these new data formed the basis for the creation of a hypothesis (often called a theory, its arguments are so convincing) of tectonics (mobility) of lithospheric plates.
The original formulation of this theory belongs to the American scientists G. Hess and R. Dietz. Later it was developed and supplemented by Soviet, French and other scientists. The meaning of the new theory is reduced to the idea that the rigid shell of the Earth - the lithosphere - is divided into separate plates. These plates experience horizontal movements. The forces that set the lithospheric plates in motion are generated by convective currents, i.e., currents of the deep fiery-liquid substance of the Earth.
The spreading of plates to the sides is accompanied by the formation of mid-ocean ridges, on the crests of which gaping rift cracks appear. Through the rifts there is an outpouring of basaltic lava.
In other areas, lithospheric plates converge and collide. In these collisions, as a rule, a subduction of the edge of one plate under another is born. On the periphery of the oceans, such modern underthrust zones are known, where strong earthquakes often occur.
The theory of lithospheric plate tectonics is confirmed by many facts obtained over the past fifteen years in the ocean.
common basis contemporary ideas about the internal structure of the Earth and the processes occurring in its depths, is the cosmogonic hypothesis of Academician O. Yu. Schmidt. According to him, the Earth, like other planets of the solar system, was formed by sticking together the cold matter of a dust cloud. Further growth of the Earth occurred by capturing new portions of the meteorite substance when passing through a dust cloud that once surrounded the Sun. As the planet grew, heavy (iron) meteorites sank and light (stone) meteorites emerged. This process (separation, differentiation) was so powerful that inside the planet the substance was melted and divided into a refractory (heavy) part and a fusible (lighter) part. At the same time, radioactive heating in the inner parts of the Earth also acted. All these processes led to the formation of a heavy inner core, a lighter outer core, lower and upper mantle. Geophysical data and calculations show that a huge energy is hidden in the bowels of the Earth, which is really capable of decisive transformations of the solid shell - the lithosphere.
Based on the cosmogonic hypothesis of O. 10. Schmidt, Academician A. P. Vinogradov developed a geochemical theory of the origin of the ocean. A.P. Vinogradov, through precise calculations, as well as experiments to study the differentiation of the molten substance of meteorites, established that the water mass of the ocean and the Earth's atmosphere was formed in the process of degassing of the substance of the upper mantle. This process continues to this day. In the upper mantle, indeed, a continuous differentiation of matter occurs, and its most fusible part penetrates the surface of the lithosphere in the form of basalt lava.
Ideas about the structure of the earth's crust and its dynamics are gradually being refined.
In 1973 and 1974 an unusual underwater expedition was carried out in the Atlantic Ocean. In a pre-selected area of the Mid-Atlantic Ridge, deep-sea dives of submersibles were carried out and a small but very important area of the ocean floor was studied in detail.
Exploring the bottom from surface vessels during the preparation of the expedition, the scientists studied the bottom topography in detail and discovered an area inside which there was a deep gorge, cutting along the crest of an underwater ridge - a rift valley. In the same area, there is a well-pronounced transform fault, which is transverse with respect to the crest of the ridge and the rift gorge.
Such a typical bottom structure - a rift gorge, a transform fault, young volcanoes - was surveyed from three submarines. The expedition was attended by the French bathyscaphe "Archimedes" with the special vessel "Marseille le Bian" providing its operation, the French submarine "Siana" with the vessel "Norua", the American research vessel "Knorr", the American submarine "Alvin" with the vessel "Lulu" .
A total of 51 deep dives were made over two seasons.
When performing deep-sea dives up to 3000 m, the crews of submarines encountered some difficulties.
The first thing that initially greatly complicated the research was the inability to determine the location of the underwater vehicle in conditions of a highly dissected terrain.
The underwater vehicle had to move, keeping a distance of no more than 5 m from the bottom. On steep slopes and crossing narrow valleys, the bathyscaphe and submarines could not use the system of acoustic beacons, as seamounts prevented the passage of signals. For this reason, an on-board system was put into operation on support vessels, with the help of which the exact location of the submarine was determined. From the support vessel, they monitored the underwater vehicle and directed its movement. Sometimes there was a direct danger to the underwater vehicle, and once such a situation arose.
On July 17, 1974, the Alvin submarine literally got stuck in a narrow crack and made attempts to get out of the trap for two and a half hours. The Alvin crew showed amazing resourcefulness and composure - after leaving the trap, they did not surface, but continued research for another two hours.
In addition to direct observations and measurements from underwater vehicles, when photographing and collecting samples, drilling was done in the expedition area from the famous special vessel "Glomar Challenger".
Finally, geophysical measurements were regularly carried out on board the Knorr research vessel, supplementing the work of underwater vehicle observers.
As a result, 91 km of route observations were made in a small area of the bottom, 23 thousand photographs were taken, more than 2 tons of rock samples were collected and more than 100 videos were made.
The scientific results of this expedition (it is known as "Famous") are very important. For the first time, submersibles were used not just for observations of the underwater world, but for purposeful geological research, similar to those detailed surveys that geologists conduct on land.
For the first time, direct evidence was obtained for the movement of lithospheric plates along the boundaries. In this case, the boundary between the American and African plates was investigated.
The width of the zone was determined, which is located between moving lithospheric plates. Unexpectedly, it turned out that this zone, where the earth's crust forms a system of cracks and where basalt lava flows out onto the bottom surface, that is, a new earth's crust is formed, this zone has a width of less than a kilometer.
Highly important discovery was made on the slopes of underwater hills. In one of the dives of the Siana submersible, fissured loose fragments were found on a hillside, very different from various fragments of basaltic lava. After the Siana surfaced, it was found that it was manganese ore. A more detailed survey of the area of distribution of manganese ores led to the discovery of an ancient hydrothermal deposit on the bottom surface. Repeated dives have yielded new materials proving that, indeed, due to reaching the bottom surface thermal waters from the bowels of the bottom in this small section of the bottom lie ores of iron and manganese.
During the expedition, many technical problems arose and there were failures, but the precious experience of purposeful geological research, gained over two seasons, is also an important result of this extraordinary oceanological experiment.
Methods for studying the structure of the earth's crust in the ocean differ in some features. The bottom relief is studied not only with the help of echo sounders, but also with side-scan locators and special echo sounders that give a picture of the relief within a strip equal in width to the depth of the place. These new methods give more accurate results and more accurately represent topography on maps.
On research vessels, gravimetric surveys are carried out using on-board gravimeters, and magnetic anomalies are surveyed. These data make it possible to judge the structure of the earth's crust under the ocean. The main research method is seismic sounding. A small explosive charge is placed in the water column and an explosion is made. A special receiver registers the arrival time of the reflected signals. Calculations determine the propagation velocity of longitudinal waves caused by an explosion in the thickness of the earth's crust. The characteristic velocity values make it possible to divide the lithosphere into several layers of different composition.
Currently, pneumatic devices or an electric discharge are used as a source. In the first case, a small volume of air compressed in a special device with a pressure of 250-300 atm is released (almost instantly) in the water. At a shallow depth, the air bubble expands sharply and this imitates an explosion. The frequent repetition of such explosions, caused by a device called an air gun, gives a continuous profile of seismic sounding and, therefore, a fairly detailed profile of the structure of the earth's crust throughout the tack.
A profilograph with an electric spark gap (sparker) is used in a similar way. In this version of seismic equipment, the power of the discharge that excites the oscillations is usually small, and a sparker is used to study the power and distribution of unconsolidated layers of bottom sediments.
To study the composition of bottom sediments and obtain their samples, various systems of soil pipes and bottom grabs are used. Ground pipes have, depending on the task of the study, a different diameter, they usually carry a heavy load for maximum penetration into the ground, sometimes they have a piston inside and carry one or another contactor (core breaker) at the lower end. The tube is immersed in water and sediment at the bottom to a certain depth (but usually not more than 12-15 m), and the core extracted in this way, usually called a column, rises to the deck of the ship.
Grab grabs, which are clamshell-type devices, seem to cut out a small monolith of the surface layer of the bottom soil, which is delivered to the deck of the ship. Self-floating bottom grab models have been developed. They make it possible to do without a cable and a deck winch and greatly simplify the method of obtaining a sample. In the coastal regions of the ocean at shallow depths, vibropiston soil tubes are used. With their help, it is possible to obtain columns up to 5 m long on sandy soils.
Obviously, all of the listed devices cannot be used to obtain samples (cores) of bottom rocks that are compacted and have a thickness of tens and hundreds of meters. These samples are obtained using conventional ship-mounted drilling rigs. For relatively small depths of the shelf (up to 150-200 m), special vessels are used that carry a drilling rig and are installed at the drilling point on several anchors. Keeping the vessel at the point is carried out by adjusting the tension of the chains going to each of the four anchors.
At depths of thousands of meters in the open ocean, anchoring a ship is technically unfeasible. Therefore, a special method of dynamic positioning has been developed.
The drilling ship goes to a given point, and the accuracy of determining the location is provided by a special navigation device that receives signals from artificial earth satellites. Then a rather complex device such as an acoustic beacon is installed on the bottom. The signals from this beacon are received by the system installed on the vessel. After receiving the signal, special electronic devices determine the displacement of the vessel and instantly issue a command to the thrusters. The desired group of propellers is turned on and the position of the vessel is restored. On the deck of the deep drilling vessel, there is a drilling rig with a rotary drilling rig, a large set of pipes and a special device for lifting and screwing pipes.
Drilling vessel "Glomar Challenger" (so far the only one) carries out work on the international project of deep sea drilling in the open ocean. More than 600 wells have already been drilled, and the maximum depth of well drilling was 1300 m. Materials of deep-water drilling have yielded so many new and unexpected facts that interest in their study is extraordinary. In the study of the ocean floor, many different techniques and methods are used, and new methods using new measurement principles can be expected in the near future.
In conclusion, a brief mention should be made of one task in the overall program of ocean research, the study of pollution. The sources of ocean pollution are varied. Discharge of industrial and domestic effluents from coastal enterprises and cities. The composition of pollutants here is extremely diverse: from nuclear industry waste to modern synthetic detergents. Significant pollution is created by discharges from ocean-going ships, and sometimes by catastrophic oil spills during accidents with tankers and offshore oil wells. There is another way to pollute the ocean - through the atmosphere. Air currents carry over vast distances, for example, lead that enters the atmosphere with the exhaust gases of internal combustion engines. In the process of gas exchange with the atmosphere, lead enters the water and is found, for example, in Antarctic waters.
Pollution definitions are now organized into a dedicated international observing system. At the same time, systematic observations of the content of pollutants in the water are assigned to the relevant vessels.
The greatest distribution in the ocean is oil pollution. To control it, not only chemical methods of determination are used, but mostly optical methods. Airplanes and helicopters are equipped with special optical devices that determine the boundaries of the area covered with an oil film, and even the thickness of the film.
The nature of the World Ocean, this, figuratively speaking, a huge ecological system of our planet, has not yet been sufficiently studied. Evidence for this assessment is provided by recent discoveries in various areas of oceanology. Methods for studying the World Ocean are quite diverse. Undoubtedly, in the future, as new methods of research are found and applied, science will be enriched with new discoveries.
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HISTORY, CURRENT STATUS AND PROSPECTS
Several periods can be distinguished in the history of ocean research and the development of oceanology. First period research from ancient times to the era of the great geographical discoveries is associated with the discoveries of the Egyptians, the Phoenicians, the inhabitants of the island of Crete and their successors. They had a good idea of the winds, currents and shores of the waters known to them. The Egyptians made their first, historically proven voyage across the Red Sea from the Gulf of Suez to the Gulf of Aden, opening the Bab el-Mandeb Strait.
Phoenician semi-merchants, semi-pirates sailed far from their native ports. Like all navigators of antiquity, they never voluntarily moved away from the coast beyond its visibility, they did not swim in winter and at night. The main purpose of their travels was to mine metal and hunt for slaves for Egypt and Babylonia, but at the same time they contributed to the spread of geographical knowledge about the ocean. The main object of their research in the II millennium BC was the Mediterranean Sea. In addition, they sailed through the Arabian Sea and the Indian Ocean to the East, where, bypassing the Malacca Strait, they possibly reached the Pacific Ocean. In the years 609-595 BC, the Phoenicians crossed the Red Sea in galleys, circled all of Africa and returned to the Mediterranean through the Strait of Gibraltar.
The discovery of the Indian Ocean is associated with the sailors of the ancient Harappan civilization that existed in the Indus basin in the III-II millennium BC. They used birds for navigational purposes and had a clear understanding of the monsoons. They were the first to master coastal navigation in the Arabian Sea and the Gulf of Oman, and opened the Strait of Hormuz. Later, the ancient Indians sailed along the Bay of Bengal, in the 7th century BC penetrated the South China Sea and discovered the Indochinese Peninsula. At the end of the 1st millennium BC, they had a huge fleet, achieved significant success in the science of navigation and discovered the Malay Archipelago, Laccadive, Maldives, Andaman, Nicobar and other islands in the Indian Ocean. The sea travel routes of the ancient Chinese ran mainly along the waters of the South China, East China and Yellow Seas.
Of the ancient navigators of Europe, it should be noted the Cretans, who in the XV?-XV centuries BC were the first to penetrate through the Sea of Marmara and the Bosporus into the Black Sea (Pontus), became the discoverers of a significant part of Southern Europe.
In ancient times, geographical horizons expanded significantly. The area of known lands and water areas has increased significantly. Geographical science has made amazing progress. Pytheas, a native of Massalia, sailed to the North Atlantic in the middle of the 5th century BC, where he first explored the phenomena of high and low tide, discovered the British Isles and Iceland. Aristotle expressed the idea of the unity of the World Ocean, and Posidonius developed this idea and clearly outlined the theory of a single ocean. Ancient scientists knew a lot about the geography of the World Ocean, they had a fairly detailed description of its nature and maps with depth measurements.
In the middle of the 6th century, Irish monks sailed far to the north and west of the North Atlantic. They were not interested in trade. They were driven by pious motives, a thirst for adventure and a desire for solitude. Even before the Scandinavians, they visited Iceland and apparently reached the island of Greenland and the east coast of North America in their wanderings. In the discovery, often secondary, after the ancient Irish, and the development of the North Atlantic in the 7th-10th centuries, the Normans played a significant role. The main occupation of the ancient Normans was cattle breeding and sea crafts. In search of fish and sea animals, they made long voyages in the northern seas. In addition, they went overseas for trade in European countries, combining it with piracy and the slave trade. The Normans sailed the Baltic and Mediterranean seas. A native of Norway, Eirik Thorvaldson (Eirik Raudi), who settled in Iceland, discovered Greenland in 981. His son Leif Eirikson (Leif the Happy) is credited with discovering Baffin Bay, Labrador and Newfoundland. As a result of sea expeditions, the Normans also discovered the Baffin Sea, Hudson Bay marked the beginning of the discovery of the Canadian Arctic Archipelago.
In the Indian Ocean in the second half of the 15th century, Arab navigators dominated. They sailed the Red and Arabian Seas, the Bay of Bengal and the seas of Southeast Asia up to the island of Timor. The hereditary Arab navigator Ibn Majid in 1462 created “Haviyat al-ihtisar...” (“Collection of results on the main principles of knowledge about the sea”), and in 1490 he completed the poem “Kitab al-fawaid ...” (“Book of benefits about principles and rules of marine science”). These navigational works contained information about the shores of the Indian Ocean, its marginal seas and the largest islands.
In XII - XIII centuries Russian industrialists-Pomors, in search of a sea animal and a “fish tooth”, mastered the seas of the Sulfur Arctic Ocean. They discovered the Svalbard (Grumand) archipelago and the Kara Sea.
In the 15th century, one of the strongest maritime powers was Portugal. At this time in the Mediterranean, the Catalans, Genoese and Venetians monopolized all European trade with India. The Genoese Union dominated the North and Baltic Seas. Therefore, the Portuguese carried out their maritime expansion mainly in a southerly direction, along the coast of Africa. They explored Western and southern shores Africa, discovered the Cape Verde, Azores, Canaries and a number of others. In 1488, Bartolomeu Dias discovered the Cape of Good Hope.
Second period study of the oceans is associated with the era of the great geographical discoveries, the chronological framework, which is limited to the middle of the fifteenth and seventeenth centuries. Significant geographical discoveries became possible thanks to the successes of science and technology: the creation of sailing ships reliable enough for ocean navigation, the improvement of the compass and sea charts, the formation of ideas about the sphericity of the Earth, etc.
One of the most important events of this period was the discovery of America as a result of the expeditions of Christopher Columbus (1492-1504). It forced us to reconsider the views that existed until then on the distribution of land and sea. In the Atlantic Ocean, the distance from the shores of Europe to the Caribbean was fairly accurately established, the speed of the northern trade wind current was measured, the first depth measurements were made, soil samples were taken, tropical hurricanes were described for the first time, and magnetic declination anomalies near Bermuda were established. In 1952, the first bathymetric map was published in Spain with the designation of reefs, banks and shallow waters. At this time, the Brazilian, Guiana Current and Gulf Stream were discovered.
In the Pacific Ocean, in connection with the intensive search for new lands, a large amount of factual material was collected on the nature of the ocean, mainly of a navigational nature. But military campaigns, merchant navigation of this period also brought actual scientific information. So F. Magellan during the first circumnavigation (1519-1522) tried to measure the depth of the Pacific Ocean.
In 1497-1498, the Portuguese Vasco da Gama opened a sea route to India along the western coast of Africa. Following the Portuguese, Dutch, French, Spanish and English navigators rushed into the Indian Ocean, covering its various parts with their voyages.
The main purpose of navigation in the Northern Arctic Ocean opening of new lands and means of communication. At that time, Russian, English and Dutch sailors tried to reach the North Pole, to pass the Northeast route along the coasts of Asia and the Northwest - along the coasts of North America. They, as a rule, did not have clear plans, the practice of swimming in ice and equipment appropriate for the polar latitudes. Therefore, their efforts did not produce the desired results. The expeditions of G. Thorn (1527), H. Willoughby (1553), V. Barents (1594-96), G. Hudson (1657) ended in complete failure. At the beginning of the 17th century, W. Baffin, trying to find the Northwest Passage, sailed along the western coast of Greenland to 77 ° 30 "N and opened the mouths of the Lancoster and Smith straits, Ellesmere Island and Devon. The ice did not allow him to penetrate into the straits, and Buffin concluded that there was no passage.
Russian researchers made a significant contribution to the study of the Northeast Passage. In 1648, S. Dezhnev for the first time passed through the strait connecting the Arctic and Pacific oceans, which later received the name Bering. However, S. Dezhnev's memorandum was lost in the Yakut archives for 88 years and became known only after his death.
The great geographical discoveries had a painful influence on the development of geographical knowledge. But, in the era under consideration, they were committed mainly by people who had a very distant relation to science. Therefore, the process of accumulating knowledge was very difficult. In 1650, the outstanding scientist of that time, Bernhard Varenius, wrote the book "General Geography", where he summarized all the new knowledge about the Earth, paying considerable attention to the oceans and seas.
Third period ocean research covers the second half of the 17th century and the entire 18th century. Distinctive features this time there were colonial expansion, the struggle for markets and dominance on the seas. Thanks to the construction of reliable sailboats, the improvement of navigational instruments, sea travel has become less difficult and relatively fast. Since the beginning of the 18th century, the level of expedition work has gradually changed. Journeys, the results of which are of scientific importance, begin to predominate. Some geographical discoveries of this period were events of world-historical significance. The coastline of North Asia was established, Northwest America was discovered, the entire east coast of Australia was revealed, and numerous islands in Oceania were discovered. The spatial outlook of the European peoples has expanded significantly thanks to the literature of travel. Travel diaries, ship's logs, letters, reports, notes, essays and other writings compiled by travelers and seafarers themselves, as well as by other persons from their words or based on their materials.
In the Arctic Ocean, the naval rivalry between Russia and England continued in the opening of the Northwest and Northeast passages. From the 17th to the 19th century, the British organized about 60 expeditions, some of the results of which did not become the property of scientists and navigators.
One of the most significant Russian expeditions of this period was the Great Northern Expedition (1733-1742) led by V. Bering. As a result of this expedition, the Bering Strait was crossed to the coast of North America, the Kuril Islands were mapped, the Eurasian shores of the Arctic Ocean were described and the possibility of navigation along them was established, etc. A sea, an island, a cape and a strait were named after V. Bering. The names of other members of the expedition are Cape Chirikov, the Laptev Sea, Cape Chelyuskin, the Pronchishchev coast, the Malygin Strait, etc.
The first high-latitude Russian expedition to the Arctic Ocean was organized in 1764-1766 on the initiative of M.V. Lomonosov. During this expedition, under the leadership of V. Ya. Chichagov, a latitude of 80 ° 30 "N was reached, interesting material was obtained about the natural conditions of the Greenland Sea, the Spitsbergen archipelago, information was summarized about the conditions and specifics of navigation in ice conditions.
In the 60s of the 18th century, Anglo-French rivalry flared up on the oceans. Round-the-world expeditions of D. Byron (1764-1767), S. Wallis (1766-1768), F. Carter (1767-1769), A. Bougainville ( 1766-1769), etc. A great contribution to the chronicle of territorial discoveries was made by the English navigator D. Cook, who made three trips around the world (1768-1771, 1772-1775, 1776-1780). One of the main tasks of his expeditions was the search for the southern mainland. He crossed the Arctic Circle three times, was convinced that the Southern Continent exists in the region of the Pole, but could not find it. As a result of the expeditions, Cook established that New Zealand is a double island, discovered the east coast of Australia, the South Sandwiches, New Caledonia, Hawaiian and other islands.
Despite the large number of expeditions and voyages, by the beginning of the 19th century, many geographical problems had not been resolved. The Southern Continent was not discovered, the Arctic coast of North America and the Canadian Arctic Archipelago were not identified, there was very little data on the depths, topography and currents of the World Ocean.
The fourth period The study of the oceans covers the 19th century and the first half of the 20th century. It is characterized by increased colonial expansion and colonial wars, a fierce struggle for markets for industrial products and sources of raw materials, and significant intercontinental migrations of the population from Europe to other parts of the world. Geographical discoveries and research in the 19th - the first half of the 20th century were carried out in more favorable conditions than in previous periods. In connection with the development of shipbuilding, new ships had improved seaworthiness and ensured greater navigation safety. From the 20s of the 19th century, sailboats were replaced by sailing ships with a steam engine as an additional propulsion, and then steamships with auxiliary sailing equipment. The introduction of a propeller since the 40s of the 19th century and the construction of ships with an iron and then a steel hull, the use of an internal combustion engine since the end of the century significantly accelerated and facilitated research work, significantly reducing the effect of weather conditions on them. A qualitatively new stage in navigation began after the invention of radio (1895), the creation of a gyrocompass and a mechanical log at the beginning of the 20th century. Living and working conditions on long-distance sea voyages have improved greatly thanks to advances in technology and medicine. Matches appeared, the industrial production of canned food and medicines was established, firearms were improved, and photography was invented.
Part of the geographical discoveries of this period was of world-historical significance. The sixth continent of the planet, Antarctica, was discovered. The entire Arctic coast of North America has been traced, the discovery of the Canadian Arctic Archipelago has been completed, the true dimensions and configuration of Greenland have been established, and the coast of the Australian mainland has been completely revealed. Literature about voyages and travels in the XX century becomes almost boundless. From it, the most important sources of new geographical information were the reports of round-the-world and polar navigators, the works of geographers and naturalists.
Since about the middle of the 20th century, the importance of collective research organized by national academies, various museums, intelligence services, numerous learned societies, institutes and individuals has increased dramatically. The limits of human activity have expanded immeasurably, all the seas and oceans have become objects of systematic study by expeditions in which general geographic and special oceanological research was carried out.
At the beginning of the 10th century, during a round-the-world voyage led by I.F. Kruzenshtern and Yu. F. Lisyansky (1803-1806) measured the water temperature at different depths of the ocean, and made observations of atmospheric pressure. Systematic measurements of temperature, salinity and density of water at different depths were carried out by the expedition of O. E. Kotzebue (1823-1826). In 1820, F. Bellingshausen and M. Lazarev discovered Antarctica and 29 islands. A great contribution to the development of science was the journey of Charles Darwin on the ship "Beagle" (1831-1836). At the end of the 1940s, the American Matthew Fontaine Maury summarized information about the winds and currents of the World Ocean and published them in the form of a book “Manual to Navigators”. He also wrote the Physical Geography of the Ocean, which went through many editions.
The largest event that marked the beginning of a new era of oceanographic research was the English round-the-world expedition on a specially equipped vessel, the Challenger (1872-1876). During this expedition, a comprehensive oceanographic study of the World Ocean was carried out. 362 deep-water stations were made, at which depth was measured, dredging and trawling were carried out, and various characteristics of sea water were determined. During this voyage, 700 genera of new organisms were discovered, the underwater Kerguelen ridge in the Indian Ocean, the Mariana Trench, the submarine Lord Howe ridges, the Hawaiian, East Pacific and Chilean uplifts were discovered, and the study of deep-water basins continued.
At the beginning of the 20th century, studies of the topography of the bottom of the Atlantic Ocean were carried out to lay a submarine cable between Europe and North America. The results of these works were summarized in the form of maps, atlases, scientific articles and monographs. During the development of the trans-Pacific submarine telegraph cable project between North America and Asia, since 1873, naval vessels began to be used to study the topography of the ocean floor. The measurements taken along the line of Fr. Vancouver - the Japanese Islands made it possible to obtain the first latitudinal profile of the Pacific Ocean floor. The Tuscarora corvette under the command of D. Belknep for the first time discovered the Markus-Necker seamounts, the Aleutian Range, the Japanese, Kuril-Kamchatka and Aleutian trenches, the North-Western and Central basins, etc.
From the end of the 20th century until the 20s of the 20th century, several large oceanographic expeditions were organized, among which the most significant are the American ones on the Albatross and Nero ships, the German ones on the Edie, Planet and Gazelle , English on "Terra-Nova", Russian on "Vityaz", etc. As a result of the work of these expeditions, new underwater ridges, uplifts, deep-sea trenches and basins were identified, maps of the bottom topography and bottom sediments were compiled, extensive material on the organic world of the oceans was collected .
Since the 1920s, an even more detailed study of the ocean began. The use of deep-sea recorder echo sounders made it possible to determine depths while the ship was moving. These studies made it possible to significantly expand knowledge about the structure of the ocean floor. Gravitational measurements in the World Ocean have refined ideas about the shape of the Earth. With the help of seismographs, the Pacific seismic ring was identified. Biological, hydrochemical and other studies of the oceans were further developed.
British expedition on the vessel "Discovery - ??" discovered the South Pacific Rise, the New Zealand Plateau, the Australo-Antarctic Rise. During the Second World War, Americans on the Cape Johnson military transport discovered more than a hundred guyots in the western Pacific Ocean.
A huge contribution to the geographical study of the World Ocean was made by polar explorers, especially Russian ones. At the beginning of the 20th century, N.P. Rumyantsev and I.F. Kruzenshtern proposed a project to search for the Northwest Passage and a detailed study of the coasts of North America. These plans were interrupted by the War of 1812. But already in 1815, O. E. Kotzebue on the brig "Rurik" went to explore the polar latitudes and discovered the bays of Kotzebue, St. Lawrence and others. In the first half of the 20th century, F.P. Wrangel and F.P. Litke carried out their expeditions. The results of these expeditions made a significant contribution to the study of the ice and hydrological regime of the Arctic Ocean. Great merit in the study of this ocean belongs to Admiral S. O. Makarov. According to his project and drawings, the first icebreaker “Ermak” was built, on which Makarov’s expedition reached 81 ° 29 "N.
The first international polar expedition in the history of human civilization was of great importance for the geographical study of the Earth. It is known as the First International Polar Year and was carried out in 1882-1883 by representatives of 12 countries of Europe and North America. The first end-to-end voyage from the Atlantic to the Pacific Ocean by the Northwest Passage was made in 1903-1906 by R. Amundsen on a small yacht “Joa”. He established that in 70 years the Northern magnetic pole shifted 50 km to the northeast. On April 6, 1909, the American R. Peary was the first to reach the North Pole.
In 1909, for the study of the Arctic Ocean, the first steel hydrographic ships of the icebreaking type "Vaigach" and "Taimyr" were built. With their help, in 1911, under the leadership of I. Sergeev and B. Vilkitsky, bathymetric work was carried out from the Bering Sea to the mouth of the Kolyma. In 1912, Russian explorers undertook 3 expeditions by G. Brusilov, V. Rusanov, G. Sedov to study the through passage along the coast of Siberia and reach the North Pole. However, none of them were successful. In 1925, R. Amundsen and L. Ellsworth organized the first air expedition to the Arctic and found that there is no land north of Greenland.
Significant research in Greenland, Barents, Kara and Chukchi was carried out in 1932-1933 as part of the International Polar Year. In 1934-1935, high-latitude complex expeditions were carried out on the ships Litke, Perseus, and Sedov. The first through navigation by the Northern Sea Route in one navigation was made by the expedition on the ship "Sibiryakov" headed by O.Yu. Schmidt. In 1937, under the leadership of I. D. Papanin, the hydrometeorological station “North Pole - 1” began to work in the ice of the Arctic.
And yet, by the end of this period, many geographical problems remained unresolved: it was not established whether Antarctica is a single continent, the discovery of the Arctic was not completed, the nature of the World Ocean was poorly studied, etc.
Beginning in the middle of the twentieth century fifth - modern period study of the oceans. At this stage in the history of mankind, science has become the main force in the development of society. The achievements of the Earth sciences have made it possible to resolve a number of global issues. Get direct evidence of the mobility of the Earth's lithosphere and its planetary divisibility. Determine the features of the structure of the earth's crust. Find the ratio of the land surface and oceans on Earth. Reveal the existence and significance of geosystems. Start using space technology to collect information about geosystems of different levels for any period of time.
After World War II, oceanographic technology improved. Three round-the-world expeditions equipped with new equipment are sent to the expanses of the World Ocean: Swedish on the Albatross (1947-1948), Danish on the Galatea (1950-1952) and British on the Challenger - ?? (1950-1952). During these and other expeditions, the thickness of the earth's crust of the oceans was measured, the heat flux at the bottom was measured, guyots and the benthic fauna of deep-sea trenches were studied. The mid-ocean ridges of the oceans and the giant faults of Mendocino, Murray, Clarion and others (1950-1959) were discovered and studied. A whole era of oceanographic research is associated with the work of the scientific vessel Vityaz. During the numerous expeditions of the Vityaz since 1949, major discoveries were made in the field of geology, geophysics, geochemistry and biology of the oceans. Long-term observations of currents were carried out on this ship for the first time, the deepest point of the ocean in the Mariana Trench was established, previously unknown landforms were discovered, etc. The work of the Vityaz was continued by the scientific ships Dmitry Mendeleev, Ob, Akademik Kurchatov ” and others. For post-war period characteristic development international cooperation in the study of the oceans. First joint work there was a NORPAK program in the Pacific Ocean, which was carried out by ships from Japan, the USA and Canada. This was followed by the international programs of the International Geophysical Year (IGY, 1957-1959), EVAPAK, KUROSIO, WESTPAK, MIOE, PIGAP, POLIMODE and others. Stationary observations in the open ocean have been developed. The largest discovery of the 1950s was the discovery of subsurface equatorial countercurrents in the Atlantic, Pacific, and Indian oceans. The accumulation and generalization of scientific data obtained during sea expeditions made it possible to reveal the patterns of air circulation on a planetary scale. Geological and geophysical studies of the World Ocean in the 1960s contributed to the development of the global theory of lithospheric plate tectonics. Since 1968 it has been running International program deep-sea drilling using the American ship Glomar Challenger. Research under this program has significantly expanded knowledge about the structure of the bottom of the World Ocean and its sedimentary rocks.
In the Arctic Sulfuric Ocean, along with specialized expeditions, laboratory and theoretical studies were carried out during this period. The features of the ocean ice cover, the structure of currents, the topography of the bottom, and the acoustic and optical properties of Arctic waters were studied. Joint international studies were carried out. The materials collected by the expeditions made it possible to eliminate the last "white spots" on the map of the Arctic. The discovery of the Lomonosov and Mendeleev ridges and a number of deep-water basins changed the idea of the topography of the ocean floor.
In 1948-1949, with the help of aviation, numerous short-term studies from three hours to several days were carried out in the ice of the Arctic. The work of the stations "North Pole" continued. In 1957, an expedition led by L. Gakkel discovered a mid-ocean ridge named after him in the Arctic Ocean. In 1963, the Leninsky Komsomolets submarine sailed under the ice to the North Pole. In 1977, a high-latitude expedition of the Institute of the Arctic and Antarctic on the nuclear icebreaker Arktika reached the Pole, which made it possible for the first time to obtain reliable, modern information about the ice of the central part of the ocean.
In the 1970s-1980s, significant scientific research was carried out in the World Ocean within the framework of the Sections program. The main objective of this program is to study the impact of the ocean on short-term fluctuations in the Earth's climate. Oceanographic, meteorological, radiation, and aerological observations were carried out in the energy-active zones of the ocean under the "Razrezy" program. More than 20 voyages of research vessels were carried out annually. The program was carried out mainly by scientists from the USSR. Unique data on the nature of the World Ocean were obtained, many scientific articles and monographs were published. Now, under the auspices of the International Committee on Climate Change and Oceanography, ocean research is being carried out under two major WOCE and TOGA programs providing for comprehensive research of the World Ocean.
The further development of oceanological research is determined by the demands of practice and the improvement of technical methods for its study. The expansion of methods and ways of using the ocean increases the requirements for predicting its state, which leads to the need for comprehensive monitoring of the World Ocean. It consists in continuous recording of surface temperature, waves, near-surface wind, frontal zones, currents, ice, etc. For its implementation, it is necessary, first of all, to develop space observation methods, communication networks for information transmission and electronic computers for its processing and analysis. It is also necessary to develop traditional methods of ocean research. The use of the entire array of information will make it possible to develop mathematical models of the structure of the ocean and its dynamics.
The increased scale of anthropogenic impact, the increase in the extraction of natural resources of the World Ocean, the development of maritime transport and recreation require a detailed study of its nature. The main task of these studies should be the development of particular mathematical models that describe individual natural processes and phenomena occurring in the World Ocean, and the creation of its integrated model. The solution of this problem will make it possible to reveal many secrets of the World Ocean, will make it possible to more effectively use its huge and absolutely necessary natural resources for man.
Deep sea research of the oceans. Man from time immemorial sought to get acquainted with the underwater world of the ocean. Information about the simplest diving devices is found in many literary monuments of the Ancient World. According to legend, the first diver was Alexander the Great, who descended into a cart in a small chamber resembling a barrel. The creation of the first diving bell should be attributed to XV? century. The first descent into the water took place in 1538 in the city of Toledo on the Tajo River. In 1660, the diving bell was built by the German physicist Sturm. This bell was about 4 meters high. Fresh air was added from bottles, which they took with them and broke as needed. The first primitive submarine was built at the beginning of the 15th century?? century in London, the Dutchman K. Van Drebbel. In Russia, the first autonomous diving equipment was proposed by Efim Nikonov in 1719. He also proposed the design of the first submarine. But only at the end of the 20th century did real submarines appear. Invented in 1798, the Klingert diving apparatus already had the qualities inherent in modern space suits. Two flexible tubes were connected to it for supplying fresh air and exhaling exhaled air. In 1868, the French engineers Ruqueirol and Denairuz developed a hard suit. The modern scuba gear was invented in 1943 by the French Jacques Yves Cousteau and E. Gagnan.
In parallel with the space suits, underwater vehicles were developed, being in which the researcher could safely work at great depths, study the environment from the porthole, collect soil samples using manipulators, etc. The first sufficiently successful bathysphere was created by the American scientist O. Barton. It was a sealed steel sphere with a quartz glass porthole, capable of withstanding great pressure. Inside the sphere were cylinders with fresh air and special absorbers that removed carbon dioxide and water vapor exhaled by people inside the chamber. A telephone wire ran parallel to the steel cable, connecting the participants of the underwater expedition with the surface ship. In 1930, Barton and Beebe made 31 dives in the Bermuda region, reaching a depth of 435 meters. In 1934 they descended to a depth of 923 meters, and in 1949 Barton brought the dive record to 1375 meters.
This ended the bathysphere dives. The baton passed to a more advanced autonomous submarine - the bathyscaphe. It was invented in 1905 by the Swiss professor Auguste Picard. In 1953, he and his son Jacques reached a depth of 3150 meters on the Trieste bathyscaphe. In 1960, Jacques Picard sank to the bottom of the Mariana Trench. Developing the ideas of his father, he invented and built a mesoscaphe. It was an improved bathyscaphe that could make autonomous voyages using ocean currents. In 1969, Jacques Picard on his mesoscaphe with a crew of six people made a multi-day voyage along the Gulf Stream at a depth of about 400 meters. Many interesting observations have been made on the geophysical and biological processes occurring in the ocean.
Since the 1970s, interest in natural resources of the World Ocean, which led to the rapid development of technology for the study of its depths. All deep-sea vehicles are divided into two large groups: uninhabited underwater vehicles (UUVs) and manned underwater vehicles (UUVs). NPAs are divided into two classes - observational and power. The first is simpler and easier. They weigh from several tens to several hundred kilograms. Their task is a detailed optical survey of the bottom, inspection of technical installations at the bottom, especially pipelines, troubleshooting, finding sunken objects, etc. For this purpose, UUVs have television and photo cameras transmitting images to the ship, sonars, orientation systems (gyrocompasses) and navigation, ultrasonic flaw detectors that allow to detect cracks in metal structures. Power UUVs are more powerful, their weight reaches several tons. They have a developed system of manipulators for self-fixing in the required areas of metal structures and carrying out repair work - cutting, welding, etc. The working depths of most UUVs are currently from several hundred meters to 7 km. The UUV is controlled by cable, hydroacoustic or radio channel. But no matter how wide the range of tasks performed by uninhabited vehicles is, one cannot do without lowering a person into the depths. Currently, there are several hundred manned underwater vehicles of various designs in the world. Among them are the Pisis submersibles (maximum immersion depth 2000 m), on which Soviet scientists explored the bottom of Lake Baikal, the Red Sea and North Atlantic rift zones. The French apparatus "Siana" (depth up to 3000 m), the American "Alvin" (depth up to 4000 m), with the help of which many discoveries were made in the depths of the ocean. In the 1980s, devices operating at depths of up to 6000 meters appeared. Two such bathyscaphes belong to Russia (“Mir-1” and “Mir-2”), one each to France, the USA and Japan (“Mitsubishi”, depth up to 6500 m).
Methods, instruments and equipment used in the study of the oceans. The ocean is studied with the help of a variety of means - from ships, aircraft, from space. Stand-alone tools are also used.
Recently, research ships have been built according to special projects. Their architecture is subject to a single goal - to make the most efficient use of instruments that are lowered to a depth, as well as those used in the study of the near-surface layer of the atmosphere. The ships are widely equipped with modern computer technology designed for planning experiments and prompt processing of the results.
To study the ocean on ships, probes for various purposes are used. The temperature, salinity and depth probe is a set of three miniature sensors that measure temperature (thermistor), salinity (conductivity sensor, based on which the salt content in water is calculated) and hydrostatic pressure (to determine depth). All three sensors are combined into a single device, mounted on the end of the cable-rope. When the device is lowered, the cable-rope is unwound from the winch installed on the deck of the ship. Data on temperature, salinity and depth are sent to the computer. There are similar probes designed to record the concentration of gases dissolved in water, the speed of sound and currents. In some cases, probes operate on the principle of free fall. Lost (disposable) probes are widely used. One of the varieties of the probe - "fish" - is a temperature, salinity and current velocity meter towed behind the ship. As a result of the development of the technique of sounding the depths of the ocean, older methods with lowering and raising thermometers, taking water samples from different depths are used less and less.
An important class of instruments are current meters capable of operating at maximum depths. Recently, electromagnetic and acoustic current meters are used more and more widely, instead of various “turntables”. In the first of them, the flow velocity is determined by the potential difference between the electrodes located in sea water. Secondly, the Doppler effect is used - a change in the frequency of a sound wave when it propagates in a moving medium.
In the study of the ocean floor, two traditional instruments are still widely used - a scoop and a geological pipe. A scoop takes a sample of soil from the surface layer of the bottom. A geological pipe can penetrate much deeper - up to 16-20 meters. To study the bottom topography and its internal structure, echo sounders of new designs are widely used - multibeam echo sounders, side-scan sonar, etc. Seismoprofilographs are used to study the internal structure of the seabed to depths of several kilometers.
The suite of autonomous ocean exploration tools is also significant. The most common of these is the buoy station. It is a buoy floating on the surface of the water, from which a steel or synthetic cable goes down to the bottom, ending with a heavy anchor lying on the bottom. At certain depths, autonomously operating instruments are fixed on the cable - temperature, salinity, and current velocity meters. Buoys of another kind are also used: an acoustic buoy of neutral buoyancy, buoys with an underwater or surface sail, laboratory buoys, etc. Autonomous bottom stations, research submarines and bathyscaphees are important autonomous means.
The use of airplanes and helicopters makes it possible to study currents and waves on the surface of the ocean. Aerial photography makes it possible to obtain interesting data on the bottom topography at shallow depths, to detect underwater rocks, reefs and shoals. Magnetic aerial photography of the ocean makes it possible to identify areas of distribution of certain minerals on the ocean floor. Sophisticated aerial photography, using a spectrum of light waves, can detect and control coastal water pollution. But airplanes and especially helicopters are tied to their bases on land, and aerial photography is based on the use of electromagnetic waves that cannot penetrate deep into the water. Therefore, space methods for studying the ocean are more promising.
Without exception, all space observation techniques are based on the use of one of the three ranges of electromagnetic waves - visible light, infrared rays and ultrahigh frequencies of electromagnetic waves. The most important parameter characterizing the state of the ocean, its surface temperature, is measured from space by radiometers using the self-radiation of this surface with an accuracy of 1 ° C. The regime of the near-surface air layer can be determined with the same accuracy. For measurements, the process of scattering of electromagnetic waves on the surface of the ocean is used. A narrow beam of radio waves is directed to the surface of the ocean at a certain angle. By the strength of their scattering in the opposite direction, the intensity of the surface ripples, i.e., the strength of the wind, is judged. At present, an accuracy of near-surface wind measurements of up to 1 m/s is achievable. One of the most important instruments installed on oceanographic satellites is the altimeter. It operates in location mode, periodically sending down radio pulses. By distorting the shape of the radar pulse of the altimeter reflected from the sea wave, it is possible, with an accuracy of 10 cm, to determine the height sea waves. In addition, it is relatively easy to register waters with increased biological productivity from space, to observe large-scale changes in its geophysical characteristics, to monitor the pollution of the World Ocean, and so on.