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Case-lesson "Oceans - an ocean of opportunity"
Case-lesson "Oceans an ocean of opportunity"

Category: Science, Nature and men

The level (grade): 9+

Subject: Natural phenomena, geography and environment

Objective: To learn about the seas and oceans, to see them from a new perspective, learn to find creative approaches to solving complex problems

What information I’m going to to find out here?

  • Which chemicals are the most common in the oceans, and why?
  • How to calculate the speed and height of the tsunami waves of the sea?
  • What kind of energy they currently are?
  • Is it possible to get oil from the sea water?
  • What are the environmental hazards pose waters of the oceans?
  • How much fresh water cost?
6 scans of the subjects, phenomena and practices:

World ocean contains most of the essential elements. Another thing that is not so easy to learn how to extract them. Also ocean carries a huge flow of energy. And here we are only learning how to transform it into electricity. It is fraught with a thousand new species of living beings. The main thing is to learn how to find them, and take care of them. Ocean is the key to the global climate, and most important thing is to learn how to use this key properly. Understanding the processes of the ocean makes the possibilities that in the future, perhaps, will provide our civilization with the necessary resources.



Ocean is a huge biochemical plant, the raw material of which is mineral and organic stockpile of land, cosmic dust, and waste products of the living organisms of the ocean. In addition, the ocean has free energy sources: solar energy (light and heat), tidal energy and geothermal energy (the internal heat of the Earth).

To date, 49 chemical elements are found in sea water. Among them are aluminum, iodine, copper, zinc, lead, tin, uranium, manganese, thorium, mercury, silver, gold, radium, and others. Content of 40 to 49 elements is so small that together they make up only 0.02 g per 1 kg of water. But the main thing is salt. Since the ratio between the main salts in seawater is constant, for determining the total salinity chlorine content is found therein, and the resulting value is multiplied by 1.81. Ocean water is a multielement solution, and also the nutrient solution.


Among the elements in ocean water there also are radioactive ones.


The salty taste of seawater cause the inorganic substances, and the most important feature of this salt solution is constant composition. The ratio of salt (by composition) remains constant at all times. Thus salinity water itself may be higher or lower depending on the latitude and the depth of water.


The salinity of the waters of the world ocean (ppm)

Measurement unit of salinity is called per mille «‰». This is the amount of solid elements in grams, dissolved in 1 kg of seawater.

At the equator, thanks to the abundant rains and relatively insignificant evaporation, ocean salinity is somewhat lower. At a latitude of about 20 ° both northern and southern, where evaporation is larger, the salinity increases. In temperate latitudes there are more rainfalls, evaporation is lower and salinity eventually decreases. For example, in the Red Sea there is no river flows, and there is almost no rain, so the salinity of the water in it reaches 40-41 ‰. Into the Black Sea flows the high-water rivers, so the salinity of the surface water is 17-18 ‰, in the White Sea - 25-26 ‰, in the Baltic Sea - only 3-4 ‰. With the depth of water in the ocean salinity is somewhat higher.

cientists explain the constancy of the salt composition of the waters of the world ocean by the two hypotheses.


Composition of ocean salt water in comparison to the river is:


Besides mineral, inorganic impurities, ocean (sea) water contains organic impurities. They are represented on the one hand by waste products and the decomposition of dead plants and animals, on the other - organic substances into the drain. Suspended organic matter is called detritus, and dissolved - humus. Detritus and organic slime sometimes form on the surface of the sea and the well-marked membranes and foam stripes.


Clutch detritus with bacteria, mucus and organic phytoplankton forms in the water column the flakes of "marine snow", which had to watch oceanauts, plunged into the sea in a bathyscaphe.

The waters of the world's oceans also contain dissolved gases. They are represented by compounds of nitrogen, oxygen and carbon. The amount of gaseous nitrogen compounds is small, however, its role is small too. It is used only by bottom nitrifying bacteria.

Oxygen, on the contrary, is of great importance. Oxygen enters the water from the air and from plant organisms, releasing it in the process of photosynthesis by the decomposition of carbon dioxide. Oxygen consumption and respiration of organisms for the oxidation of dead organic matter. In periods of intensive development of phytoplankton, or, as they say oceanographers, during the period of "flowering" (although phytoplankton, of course, does not bloom), the water in the surface layers of the ocean is even supersaturated with oxygen. At this time, some of it is released into the atmosphere.


As the depth of the content of dissolved oxygen in the sea water decreases. At a certain depth, approximately 400-800 m layer, in all the oceans, especially in the Indian Ocean, there is a fairly sharp drop in the oxygen content in the water. It is assumed that this layer is intensive oxygen consumption during the oxidation of dead organic matter. Below this layer the oxygen content rises again, and then drops to the bottom again.

In some areas of the ocean on the oxidation of humus consumed all the oxygen contained in the water. Then the bacteria start to consume oxygen-sulfur compounds (sulfates) and isolated gas with the hydrogen sulfide. This phenomenon is well known in the Cariaco Trench in the Caribbean Sea and the Black Sea, where a certain depth and extends to the bottom hydrogen sulphide zone, which does not have any life, except for hydrogen sulfide bacteria. Annual consumption of oxygen in the oxidative processes in the ocean is 35 billion. t.

Another chemical properties of seawater is a bactericidal effect. Seawater ruins even staphylococci, which are unaffected by penicillin. Some bacteria are killed in seawater for 24 hours.


Which of the two hypotheses to explain the persistence of the salt composition of sea water, seems right to you? Why?

One of the natural phenomena which we associate the seas and oceans with are waves. However, the wind sea waves and tsunamis are distinguished by their physical characteristics.

Wind waves. The first measurements of the waves of the Mediterranean Sea were made the Italian scientist Luidzhi Marsili in 1725.


In the early twentieth century the measurements of the wave height were performed using a highly sensitive barometer (altimeter). This device accurately records the rise and fall of the ship on the waves, but it, unfortunately, feels well and all sorts of interference, in particular, differences in barometric pressure, which are rapidly advancing, and are repeated several times in a strong wind.

Much more precisely respond to the excitement of manometers is lying on the bottom. With the passage of the pressure wave of the instrument varies, and the signals on wires coming ashore or recorded directly on the bottom of the recorder. In this way, one can only measure the height of the waves in shallow water where the depth comparable to the height of the waves. At greater depths, in accordance with the law of Pascal pressure equalized, and with increasing depth is less dependent on the height of waves. Today the waves are studied by means of complex and very precise instruments, operating automatically and displaing information in ready digital data columns.

Typhoons in the Pacific were marked by grandiose waves, 30 meters height.

To man standing on the deck of a ship in a stormy sea, the waves seem to be very steep, hanging like the walls. In fact they are gentle. Typically, the wavelength is 30-40 times its height, only in rare cases the ratio of wave height to its length is equal to 1:10. Thus, the maximum steepness of the waves in the open ea is never more than 18 degrees.

The length of the storm waves does not exceed 250 meters. Accordingly, the propagation velocity is 60 km per hour. Swell, the longer (up to 800 meters or more), roll speed of about 100 kilometers per hour, and sometimes even faster.

Strictly speaking, such a rate is not moving water mass that forms a wave, but only its form, more wave energy. Water particles in the waves of the sea does not produce reciprocating and oscillating movements, and sometimes enters the observer astray.


It varies in two directions simultaneously. In the vertical plane of its fluctuations are explained by the difference in level between the crest of the wave and its sole. They occur under the influence of gravitational forces. But since when lowering the crest to the level of the sole water is pushed to the side, and when it is uplifting returned to its original place, the particles of water involuntarily oscillates also in the horizontal plane. The combination of the two movements leads to the fact that the water particles are moving in circular orbits whose diameter is at the surface of the wave height. More specifically, they describe a spiral, because under the influence of wind and also water gets translational movement, whereby, as has been said, there are sea currents.

The vibrational motion of the particles of water decreases rapidly with depth. When the wave height is equal to 5 meters (the average height of the waves in a storm), and the length of 100 meters, it is no longer a depth of 12 meters diameter of the orbit of the wave of water particles is 2.5 m, and a depth of 100 meters - only 2 centimeters.

A special kind of wave is tsunami.


Tsunami waves are long waves. The distance from crest to crest (wave length) much greater than the depth of the ocean.

Tsunami and tides are different from conventional wind (storm) waves and ocean swell. Wind waves affect only the top layer of the ocean, the waving at a depth of 50 m has not felt. And the tides and currents caused by tsunami waves involve moving the entire body of water - from the bottom to the surface.

The speed of propagation of the tsunami wave is determined by the depth of the ocean of H and gravitational acceleration g:


If the fluid is infinitely deep, the only variable having a linear dimension is the wavelength. Another physical parameter - is the gravitational constant g (9,81 m / s2), which provides a restoring force when vibrations of the water particles. Other physical parameters that affect the speed, not.


Experts service that warn about tsunami waves, having received information about the strong underwater earthquake (epicenter of the position) is calculated during the wave approaches the shore on a formula taking into account the coordinates of the point on the map the depths (x and y).


As with all types of waves (sound, light, radio waves), tsunami experience attenuation, reflection, refraction and scattering.

Wave attenuation. In the open ocean with a flat bottom wave energy decays as 1 / r, where r - the distance from the source. Accordingly, the amplitude (height) as the wave decreases in inverse proportion. It is also experiencing a wave attenuation due to scattering by the irregularities of the bottom relief.

Reflection. Reflected waves from the steep bank are leading to a doubling of its amplitude on the beach. If the amplitude of the incoming waves of 5 meters, then the reflection on the shore line height is 10 m. The reflection coefficient from the coast, close to the wall 1. However, if the receding shore, when the output wave in shallow ridge collapse occurs.

When the height of a wave is comparable to the water depth H, the difference between the velocities of the "sole" of the wave and its crest becomes essential.

The velocity of the top of the wave is equal to:


The top of the wave catches up with the sole. Naturally, then the reflection coefficient becomes significantly less than unity. Wave energy is consumed in this case, at the friction in full flow.

Refraction. In the role of the refractive index for the speed of tsunami waves acts. The smaller the depth of water, the propagation speed of less. Accordingly, the "ray" Tsunami always bent toward the shallows. Features topography can create additional effects. On the shelf, the depth of which an average of 200 m, can be formed so-called "trapped" wave.


The energy of a tsunami. The energy carried by the waves of the tsunami can be assessed. During an earthquake over the fire formed the initial displacement of the ocean surface. It is believed that all the energy tsunami at this time is represented in the form of potential energy raising the liquid column over the fire.

The average height of the ocean surface displacement is indicated by a. The potential energy is expressed by the formula:


For the typical dimensions of powerful earthquakes sources believe the size of 1000 km by 1000 km.


For a source with an average height of surface displacement a = 0,5 m is roughly 1014 J, which equals the energy of the bombs exploded in Hiroshima.


How fast will tsunami move at a depth of 2500 m?

The phrase "World Ocean is an Ocean of Technology" - it is a fair phrase. Technology can be divided into the trivial (the ones that are relatively used for the long time) and innovation. The trivial technologies include oil and gas production from offshore and oceanic shelf.

Oil and gas.


Oil and natural gas extraction in the waters of the oceans is already quite a long story. Primitive way of offshore oil led in the XIX century in the United States (California) and Japan. The beginning of the really rapid growth in offshore oil and gas belongs to the 1960s.

Volumes famous sea oil reserves vary between 240-300 bln. Tons, and modern production is only 25% of the known deposits. The total volume of oil reserves is based explored deposits, currently investigated by only about 2% of the continental shelves.

Aquaculture. This includes breeding and rearing of aquatic organisms (fish, crustaceans, molluscs, algae) in natural and artificial reservoirs, as well as specially designed marine plantations. Aquaculture, in particular the breeding of freshwater fish, has about 4 thousand years. In China, about 3,750 years ago were fish ponds for breeding.


It is possible that further growth of the fishing industry will be provided mainly through aquaculture.

In some cases, aquaculture can reduce poaching on wild populations, in order to develop sport fishing. Also produced in the Fishery caviar and sturgeon are grown only legitimate alternative poached eggs and fish.

By the innovative technologies can be safely attributed power "tidal type" receiving fuel from algae, extraction of some chemical elements from sea water.

Tidal Power Plant (TPP) is a special type of hydroelectric power using tidal energy (kinetic energy of rotation of the Earth). Tidal power is built on the shores of the seas, where the gravitational forces of the moon and the sun twice a day changes the water level. Fluctuations in water levels at the coast can reach 18 meters.


Obtaining fuel from algae. Research in this area is carried out in different countries. For example, the Pacific Northwest National Laboratory US Department of Energy has developed a new method of converting algae into oil. A process that takes millions of years in nature, in special chemical reactor takes less than an hour. For energy it is needed only green algae, and fresh water heated to a certain temperature.

For such a conversion of algae requires only a simple chemical reactor operating on the principle of a conventional cooker. First, it is charged with algae and then hot water is fed under high pressure of 20.7 MPa and temperature of 350 degrees. This technology is not provided for drying the algae is allowed their water content to 90% by weight.

The result of the chemical reaction between components of algae and water becomes a pure oil, which can be easily processed into gasoline on the already existing plants. The duration of one cycle is 45-50 minutes.


Furthermore, as a by-product produced biogas which can be used to produce methane or burn to heat the reactor.

Extraction of chemical elements from sea water.

Besides the huge amount of salt in the water column of the ocean is stored as non-ferrous metal stocks all fields of the globe compared to them are insignificant.


In turn, the supplies of fresh water on Earth decrease. One solution to this problem is the desalination of sea water. And the concentrate of sea water is a valuable source of raw material for the production of metals.


Removing the metals from the concentrate is carried out both by means of ion-exchange sorption materials (materials, "transmissive" connecting part of the molecule), and by means of special bacteria - a biotechnological method.

Every year brings new technologies waters of the oceans. This becomes important compliance with environmental laws, principles, known as the "law of the Commoners."



Do you agree with these laws, principles? Give examples from your life, or from your own observations.

Speaking of the seas and oceans, unfortunately, it is impossible not to touch the issue of environmental pollution and ecological disasters because of the anthropogenic impact on the world's oceans. And, considering that the world's oceans is a huge and complex biogeochemical system, exposure at any level (the water of the seas, rivers, precipitation, ground water) will inevitably affect the whole system. This is the most striking, and has become a classic example: during the "Fashion on pesticides" the widespread use of DDT led to the fact that the pesticides were detected even in the blood of penguins in Antarctica.


But organic substances of different groups and continue to come into the waters of the oceans. And, given the presence of chloride ions in the oceanic water, this leads to more toxic secondary pollution - dioxin contamination.


For the oceans, as well as for any complex systems, characterized by the law Ashby "controlling" system is always more difficult then the "controlled" one, but the change of one changes the whole.

Man-caused impact on the environment can be classified according to the types (physical, chemical, biological) and on the "origin" (waste water pollution from water transport, waste disposal).


Pollutants can get into ecosystem both from sewage companies, and with the precipitation, and can also be the result of accidents in the offshore gas and oil production and oil transportation.



Physical pollution is represented primarily by thermal pollution. Resulting from the discharge of heated waste water power plants and some industries (increases the temperature by 6-8 degrees Celsius). The area of these spots can be up to 30 square kilometers. This prevents the water exchange, reduces the solubility of oxygen in the background of increasing consumption. Runs mechanism of hypoxia (oxygen deficiency) in aquatic organisms, which can lead to mora.


Mechanical contamination is also called "garbage patches". Currently, five large known clusters of "garbage patches"are situated in the Pacific(two), Atlantic(two) oceans, and in the Indian Ocean(one). These garbage cycles consist mainly of plastic waste generated as a result of discharges from the densely populated coastal areas of continents.


To protect the waters of the oceans a number of measures are taken, including clean waters, monitoring (including global), the legislative regulation of water protection (inland waters as well).


The ocean has always been attractive for artists. Waves, ships, sunsets, the sailors - all of these has often been the subject of art. Blue, turquoise, ultramarine, electrician, indigo, Blanker - this is not a complete list of colors that play waves on marine painters paintings.

Marina - a genre of fine art depicting a naval battle or sea view or as a kind of landscape. It was an independent type of landscape painting at the beginning of the XVII century in Holland. Example of marina by Dutch artist - a painting "The Storm on the Sea of Galilee" (1633) by Rembrandt.


The most famous artists are marine painters William Turner and Ivan Aivazovsky.

The famous "The Ninth Wave" by Aivazovsky:


Aivazovsky painted the sea, that has not yet calmed down after a violent night storm, and people shipwrecked in the ocean. The rays of the rising sun illuminate the rolling waves: the upper part of the canvas is painted in purple and gold tones - so stained the sky, passing through the swirling, like fog, clouds, the first rays of the sun. The biggest of them - the ninth wave is ready to attack the people again. Therefore, the artist depicted an alarming sea blue and green colors, the wave crests which are iridescent. With remarkable skill and force transferred Aivazovsky splendor of sea waves. On the canvas everything is in the motion, and the sea along with the rise and heavily crumbling waves seem to really "live".

One of the most famous paintings of William Turner is "The last flight of the ship" Valiant ":


France has the official title of the artist's Navy, assigned to the Minister of Defence of the outstanding marine painter. The title can be applied not only to artists, but also photographers, illustrators, engravers and sculptors.


Consider the installation option that can desalinate 35 cubic meters of seawater per day. Typical desalination plant for th e waters of the Black and Azov Seas will include:


The features of its operation will be:

• the need for replenishment of reagents;

• replacement of filter elements (bags and fillers);

• replacement of membranes.



The cost of operation of such a facility will be UAH 16,383.5. per month. When the performance of 35 cubic meters per day cost of 1 cu. meters of desalinated water will be 15.6 UAH.

Lesson summary






As a result of Case Knowledge Hypermarket can add the following findings of students:



What are the 3 most significant sites help getting information?






To help the student and coach:







Where to take information of the Case:









http://www.fao.org/aquaculture/ru/ аквакультура







Locations of the lesson:


Case lesson takes place in the classroom. Carrying classes at the museum, park, library...



Teams of boys and girls.

The score of the competition between teams was

Targets for them:

1. Which team will namemore chemical elements and compounds present in sea water?

2. How fast will tsunami move in Tonga Trench, if its depth of 10,882 m?




Make 5 questions to the case lesson material (individual task).


Duration of Case:


90 minutes(double lesson).



Ability to circuit classes with student-double for:




The results produced and competence:

- The ability to quickly find information on the topic and around;

-  Getting practical skills to use the information obtained.

- Obtaining specific knowledge in mathematics, physics, chemistry, geography, technology, and other sections (shown in the scans).




heavy metals, salts, biogeochemical cycle, wave, aquaculture, tidal power, flow, ridges, plankton, desalination



Grabovskaya Larisa Leonidivna


Took part in case apgrade:


The End

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