The "lungs of the planet" are in the ocean. Main producers of oxygen

The Earth contains 49.4% oxygen, which occurs either free in the air or bound (water, compounds and minerals).

Characteristics of oxygen

On our planet, oxygen gas is more common than any other chemical element. And this is not surprising, because it is part of:

rocks,
water,
atmosphere,
living organisms,
proteins, carbohydrates and fats.

Oxygen is an active gas and supports combustion.

Physical properties

Oxygen is found in the atmosphere in a colorless gaseous form. It is odorless and slightly soluble in water and other solvents. Oxygen has strong molecular bonds, which makes it chemically inactive.

If oxygen is heated, it begins to oxidize and react with most non-metals and metals. For example, iron, this gas slowly oxidizes and causes it to rust.

When the temperature drops (-182.9°C), and normal pressure gaseous oxygen changes to another state (liquid) and becomes pale blue. If the temperature is further reduced (to -218.7°C), the gas will solidify and change to the state of blue crystals.

In liquid and solid states, oxygen turns blue and has magnetic properties.

Charcoal is an active oxygen absorber.

Chemical properties

Almost all reactions of oxygen with other substances produce and release energy, the strength of which can depend on temperature. For example, at normal temperatures this gas reacts slowly with hydrogen, and at temperatures above 550°C an explosive reaction occurs.

Oxygen is an active gas that reacts with most metals except platinum and gold. The strength and dynamics of the interaction during which oxides are formed depends on the presence of impurities in the metal, the state of its surface and grinding. Some metals, when bound with oxygen, except basic oxides form amphoteric and acidic oxides. Oxides of gold and platinum metals arise during their decomposition.

Oxygen, in addition to metals, also actively interacts with almost all chemical elements(except halogens).

In the molecular state, oxygen is more active and this feature is used in the bleaching of various materials.

The role and importance of oxygen in nature

Green plants produce the most oxygen on Earth, with the bulk produced by aquatic plants. If more oxygen is produced in the water, the excess will go into the air. And if it is less, then on the contrary, the missing amount will be supplemented from the air.

Marine and fresh water contains 88.8% oxygen (by mass), and in the atmosphere it is 20.95% by volume. In the earth's crust, more than 1,500 compounds contain oxygen.

Of all the gases that make up the atmosphere, oxygen is the most important for nature and humans. It is present in every living cell and is necessary for all living organisms to breathe. The lack of oxygen in the air immediately affects life. Without oxygen it is impossible to breathe, and therefore to live. A person breathing for 1 minute. on average it consumes 0.5 dm3. If there is less of it in the air to 1/3 of it, then he will lose consciousness, to 1/4 of it, he will die.

Yeast and some bacteria can live without oxygen, but warm-blooded animals die within minutes if there is a lack of oxygen.

Oxygen cycle in nature

The oxygen cycle in nature is the exchange of oxygen between the atmosphere and oceans, between animals and plants during breathing, as well as during chemical combustion.

On our planet important source oxygen - plants in which the unique process of photosynthesis takes place. During this, oxygen is released.

In the upper part of the atmosphere, oxygen is also formed due to the division of water under the influence of the Sun.

How does the oxygen cycle occur in nature?

During the respiration of animals, people and plants, as well as the combustion of any fuel, oxygen is consumed and carbon dioxide is formed. Then the carbon dioxide feeds the plants, which again produce oxygen through the process of photosynthesis.

Thus, its content in the atmospheric air is maintained and does not end.

Applications of oxygen

In medicine, during operations and life-threatening diseases, patients are given pure oxygen to breathe in order to alleviate their condition and speed up recovery.

Without oxygen cylinders, climbers cannot climb mountains, and scuba divers cannot dive to the depths of seas and oceans.

Oxygen is widely used in different types industry and production:

for cutting and welding various metals
to get very high temperatures in factories
to obtain a variety of chemical compounds. to accelerate the melting of metals.

Oxygen is also widely used in the space industry and aviation.

Since childhood, we know that trees are the main source of oxygen on the planet. Later, in biology classes, I learned that oxygen is produced as a result of photosynthesis, a process that occurs in the green cells of plant leaves in the light. From simple substances- water and carbon dioxide complex chemical compounds are formed - sugars, which are then converted into starch, fiber, proteins and fats, and oxygen is released.

There are fewer and fewer forests on our Planet every year. Why don't we feel a lack of oxygen? Maybe plants absorb carbon dioxide and the oxygen they produce is enough for people in abundance? I decided to conduct experiments and prove that green plants absorb carbon dioxide from the air and release oxygen.

Description of the experience

Equipment: indoor plant with large leaves, two liter jars, glass plates (or replacement), petroleum jelly, a wide container of water, a glass (plastic or other) tube 30-40 cm long, splinters, matches.

Progress of the experiment:

We put 5-6 large leaves, plucked from indoor plant. We fill the jar with the leaves with water, cover it with a plate and, turning it upside down, lower it into a wide container of water.

Then we displace the water from the jar by exhaling carbon dioxide through the tube. Pressing the neck of the jar tightly with a plate under water, remove it from the water and turn it over. We do the same with a jar without leaves. Let's open the jar and insert a burning splinter inside.

The light instantly went out. Consequently, the air is saturated with carbon dioxide. Let's do the same with the second jar.

Coat the necks of the jars with Vaseline. Let's put it on the window. You can leave the light on overnight.

After a day or two, we carefully open the jar of leaves that was in the light and lower a burning splinter into it.

The splinter is burning, which means oxygen has appeared, since oxygen is necessary for combustion. We do the same with the second jar. The torch goes out.

* The air in a jar with leaves standing in the light changed - oxygen appeared in it;

* There were no changes in the second bank.

This means that leaves produce oxygen in the light.

Problem

Then I had a question: if for the winter larger territory Earth's trees shed their leaves, why don't we feel a lack of oxygen? Why don't we suffocate in winter?

And I suggested: maybe there is some other source of oxygen?

1. Collect information in the literature, on the Internet on the topic of interest.

2. Find answers to problematic issues:

> How much oxygen does one tree produce per year? How much carbon dioxide does it absorb?

> How much oxygen does the average person need per year to breathe?

> What is the area of forests on the planet?

> How many people live on the planet?

> Where else is oxygen used besides human breathing? In what quantity?

> Is there enough oxygen produced by trees to breathe?

3. Draw conclusions. Prepare a presentation of the work.

1. How much oxygen does one tree produce per year? How much carbon dioxide does it absorb?

On average, one tree produces 2.5 kilograms of oxygen per day, and 912.5 kilograms of oxygen per year. It is known that 50 m of green forest absorbs in 1 hour the same amount of carbon dioxide as one person emits it when breathing in 1 hour, i.e. 40 g.

Let's calculate the amount of carbon dioxide produced by all of Humanity (6 billion) in 1 day and the amount of carbon dioxide that can absorb the entire forest area (4 billion hectares):

50 m x 24 h = 1200 m - S of the forest required to absorb the carbon dioxide produced by 1 person per day.

1200 x 6 billion = 720,000,000 hectares - S forests, necessary to absorb the carbon dioxide produced by all of Humanity in 1 day.

720,000,000 hectares: 4,000,000,000 hectares = 0.18 times - so many times less than the existing forest S required to absorb the carbon dioxide produced by all of Humanity.

I would like to point out that different sources provide different data, so the calculations are approximate.

2. How much oxygen does an average person need per year to breathe?

One person needs 0.83 kg of oxygen per day to breathe; 302.95 kg of oxygen per year.

3. What is the area occupied by forests on the planet?

The estimated forest area on the planet is slightly more than 4 billion hectares, or 30% of the land area. But not all of these lands are occupied by trees themselves - they also include clearings, roads, and clearings. Forests occupy about 3 billion hectares.

4. How many people live on the planet?

More than 6 billion people live on the planet.

5. Where else, besides human breathing, is oxygen used? In what quantity?

When burning 1 kg of coal or wood, more than 2 kg of oxygen is consumed. This is approximately the oxygen produced by one tree.

One passenger car burns 1825 kg of oxygen for every 100 km of travel. This is approximately the oxygen produced by 734 trees. The combustion of 1 kg of gasoline requires about 300 kg of oxygen, and in an hour of operation, the engine of an average passenger car absorbs as much oxygen as a person needs to breathe for a month. Every year, a car absorbs an average of more than 4 tons of oxygen from the atmosphere, emitting approximately 800 kg of carbon monoxide, about 40 kg of nitrogen oxides and almost 200 kg of various hydrocarbons with exhaust gases. If you multiply these figures by the 400 million units of the global car fleet, you can imagine the extent of the threat hidden in excessive motorization.

6. Is there enough oxygen produced by trees for the population of the planet to breathe?

A lot of oxygen is released by tropical forests, which are often called >. At the same time, it is true that it is silent that in a year tropical forests consume almost as much oxygen as they produce. It is spent on the respiration of organisms that decompose finished organic matter, primarily bacteria and fungi.

The forest area is about 3 billion hectares, approximately 0.8 hectares per person. It's not that much. 14-15% are occupied by northern coniferous forests(Russia, Canada and USA), 55-60% - tropical forests. Canada has the most forests per capita - 9.4 hectares.

If you imagine that one car burns 1825 kilograms of oxygen on average per year. And one tree produces 912.5 kilograms per year. There are 400 million cars in the world, and their number is constantly growing. The number of trees is constantly decreasing.

The total rate of oxygen production by plants during photosynthesis in 1 year is 1.55x10 tons.

Oxygen consumption for 1 year - 2.16x1010 tons.

After analyzing the information and making calculations, I learned that the oxygen produced by forest plants during photosynthesis is not enough for breathing.

The question arises: are there other sources of oxygen?

I began to collect information to answer this question. It turned out that the share of oxygen produced by trees is 10 - 30% (according to different sources) from all the oxygen contained in the atmosphere. The remaining 70 - 90% is given to us by the Ocean. Oxygen is produced as a result of photosynthesis by cyanobacteria and phytoplankton living in the water column, some of which are blue-green algae. And since the area of the Ocean is three times larger, and there is more phytoplankton with algae in it than trees on land, the ocean will produce more oxygen.

After answering my questions, I learned that there are other sources of oxygen on earth. And these sources produce much more oxygen than trees. But this does not reduce the role of forests on the Planet. Plants are the only sources nutrients. After all, animals are not capable of producing energy themselves. They depend on the supply of nutrients created by plants and receive vital energy from them.

Everything in nature is interconnected. Ocean pollution can lead to a decrease in oxygen on the planet. Tropical rainforests play a vital role in regulating the climate on our Planet: they occupy a special position in the cycles of oxygen, carbon and water. More than 50% of our planet has already been destroyed. rain forests, and their destruction continues.

We must protect and preserve everything that nature has given us.

State budget educational institution additional

children's education Palace of children's (youth) creativity

Pushkinsky district of St. Petersburg

State budgetary educational institution high school №530

with in-depth study of natural and mathematical subjects

Pushkinsky district of St. Petersburg

TOPIC OF THE WORK:

"Oxygen sources on our planet"

The work was completed by a 2b grade student

GBOU school No. 530 with in-depth study

subjects of the natural and mathematical cycle:

Komburley Ksenia

Head: Yanson Lina Viktorovna,

teacher primary classes

St. Petersburg - Pushkin

2016

Content

Introduction………………………………………………………………………………... 3

Hypothesis, purpose of the study………………………………………………………. 4

Objectives……………………………………………………..……………………………. 4

Chapter 1. Literature review

Chapter 2. Practical part

Conclusions………………………………………………………………………………. 17

Conclusion ……………………………………………………………………………. 18

References………………………………………………………………………………. 19

Introduction

We often hear that trees are the main source of oxygen on the planet. But is this true? In my research work, I tried to find out whether trees are really the main source of oxygen or whether it has other origins.

The proportion of oxygen in the air is 21%. All the oxygen that almost all living creatures on our planet breathe is released by plants during the process of photosynthesis, a process that occurs in the green cells of plant leaves in the light. From simple substances, complex chemical compounds are formed, which are then released into oxygen. This gas, essential for life, rises into the atmosphere and is then evenly distributed throughout it.

There are fewer and fewer forests on our planet every year. Why don't we feel a lack of oxygen? Recently, while watching a TV show, I heard that the World Ocean is called “ lungs of the planet" I wondered what the ocean had to do with it if it was a huge amount of water. It turns out that oxygen in water is produced as a result of photosynthesis by phytoplankton living in the water column.

I decided to study various literature, Internet resources, and also conduct experiments and find out what actually is the main source of oxygen on our planet.

Hypothesis

Is it possible that the oxygen produced in the waters of the World Ocean in huge quantities enters the atmosphere, and is not only used by the inhabitants of the ocean?

Target research work:

Find out what is the main source of oxygen on our planet and why the World Ocean is called the “lungs of the planet.”

Tasks

Collect information on a topic of interest.

Learn about the process of photosynthesis, the main source of oxygen on Earth.

Find the answer to the question:

Where else besides breathing is oxygen used, and in what quantity?

Study the main sources of oxygen and conduct a comparative analysis.

Summarize the results of the work and draw conclusions.

Chapter 1. Literature review

1.1 In the oceans

The entire surface of the World Ocean is in contact with the atmosphere. And it is natural that at the turn of these elements there is an intensive exchange between them. Gases, moisture and heat move in both directions. Every day, about 13 thousand cubic kilometers of water are in the atmosphere in the form of vapor. This permanent fund of moisture is constantly replenished due to the evaporation of water from the surface of the ocean and is consumed by falling onto the surface of the planet in the form of precipitation.

Total weight The water that the ocean releases to the atmosphere is about 355 thousand cubic kilometers per year. Back, from the air to the sea, only 320 thousand cubic kilometers return. The rest of the water (35 thousand cubic kilometers) goes through a complex cycle on land before returning to the ocean.

Thus, only one tenth of the huge amount of moisture that evaporates from the surface of the World Ocean irrigates forests and fields, and nine tenths circulate in the closed “sea-atmosphere” system.

In the lower layers of the atmosphere, air is composed of 78 percent nitrogen and 21 percent oxygen (in addition, it contains the noble gases hydrogen and carbon dioxide, which together make up 1 percent of the volume). The solubility of different gases in water varies; there, oxygen dissolves in it much more easily than nitrogen, so the volumetric ratio of oxygen to nitrogen in ocean waters is 1:2, and not 1:4, as in air.

Oxygen dissolved in the waters of the World Ocean fully meets the need marine organisms, due to it, the oxidation of organic and mineral products also occurs. Nevertheless, there is always excess oxygen in the water, which evaporates into the atmosphere. It enters the atmosphere especially abundantly in places where it grows marine plants, primarily unicellular planktonic algae.

Scientists suggest that all the oxygen in the air envelope of our planet was formed through photosynthesis and its presence in the atmosphere is maintained by green plants. As is known, in the twentieth century, as a result of the growth of cities and industrial enterprises, the land area occupied by green plants decreased sharply. Forest areas, which provide a considerable share of the oxygen synthesized by terrestrial vegetation, are shrinking especially catastrophically.

In this regard, the role of the ocean in the regeneration of the Earth’s air shell increases even more. The oceans not only enrich the atmosphere with oxygen, but also help remove carbon dioxide from it, which is formed as a result of the respiration of living organisms and as one of the consequences of the destruction of rocks and volcanic activity. The relative amount of this substance in the air is negligible and equal (by volume) to 0.03 percent. However, its role in the formation of global climatic conditions and for the normal development of life is completely disproportionate to such a small value.

1.2 What is oxygen?

So what is oxygen? Oxygen is an invisible gas, tasteless, odorless, and gaseous under normal conditions.

Many scientists in the past guessed that there was a substance with properties that we now know are inherent in oxygen.

Oxygen was discovered almost simultaneously by two outstanding chemists of the second half of the 18th century. Swede Karl Wilhelm Scheele and Englishman Joseph Priestley. Scheele received oxygen earlier, but his treatise “On Air and Fire,” which contained information about oxygen, was published later than the message about Priestley’s discovery.

Oxygen is the most abundant element on our planet. It is part of water (88.9%), but it covers 2/3 of the surface globe, forming it water shell hydrosphere. Oxygen is second in quantity and first in importance for life component the air envelope of the Earth's atmosphere, where it accounts for 21% (by volume) and 23.15% (by mass). Oxygen is a component of numerous minerals in the hard shell earth's crust lithosphere: out of every 100 atoms of the earth's crust, oxygen accounts for 58 atoms.

As you already know, ordinary oxygen exists in the form O 2 . It is a colorless, odorless and tasteless gas. In the liquid state, oxygen has a light blue color, in the solid state it is blue. Oxygen gas is more soluble in water than nitrogen and hydrogen.

Oxygen is also involved in slow oxidation processes various substances at normal temperature. These processes are no less important than combustion reactions. Thus, the slow oxidation of food in our body is the source of energy on which the body lives. Oxygen for this purpose is delivered by hemoglobin in the blood, which is capable of forming a weak connection with it already at room temperature. Oxidized hemoglobin oxyhemoglobin delivers oxygen to all tissues and cells of the body, which oxidizes proteins, fats and carbohydrates (components of food), thereby forming carbon dioxide and water and releasing the energy necessary for the body’s activities.

The role of oxygen in the breathing process of humans and animals is extremely important.

Plants also absorb atmospheric oxygen. But if in the dark only the process of plants absorbing oxygen occurs, then in the light another opposite process occurs - photosynthesis, as a result of which plants absorb carbon dioxide and release oxygen. Since the process of photosynthesis is more intense, plants end up releasing much more oxygen in the light than they absorb during respiration. Thus, the content of free oxygen of the Earth is preserved due to the vital activity of green plants.

1.4 Photosynthesis

Photosynthesis – is the formation of sugars from water and carbon dioxide using energy sunlight, which releases “production waste” - oxygen, which is necessary for almost all organisms to breathe. Respiration produces carbon dioxide again, which is needed for photosynthesis. Photosynthesis maintains the balance of these two gases in the atmosphere.

Solar energy for photosynthesis is captured by the pigment chlorophyll, which gives green grass and leaves. This pigment plays a major role in photosynthesis.

In algae, chlorophyll is contained in chromatophores (pigment-containing and light-reflecting cells), which have different shape. Brown and red algae, which live at considerable depths where access to sunlight is difficult, have other pigments.Photosynthetic organisms are located at the very bottom of the food pyramid, therefore they are a source of food for all life on the planet. Oxygen released during photosynthesis enters the atmosphere. IN upper layers Ozone is formed from oxygen in the atmosphere. The ozone shield protects the Earth's surface from hard ultraviolet radiation, which made it possible for living organisms to reach land.

Chapter 2. Practical part

2.1 Plants absorb carbon dioxide from the air and release oxygen.

I decided to conduct experiments and prove that green plants absorb carbon dioxide from the air and release oxygen.

Progress of the experiment:

We put leaves picked from a houseplant in one jar. I use a candle to displace oxygen from the jar, i.e. During the combustion process in a closed jar, oxygen turns into carbon dioxide, and the candle goes out. I close the jar tightly with a lid.

We do the same with a jar without leaves.

As a result of the experiment, I am left with 2 closed jars containing carbon dioxide, while one jar is empty, and the other contains leaves of a houseplant.

We close the jars tightly and leave them for 2 days, while they are exposed to sunlight and artificial light (lamp light).

After two days, carefully open the jar with leaves (it should be noted that a small amount of moisture has formed on the walls of the jar) and lower a burning candle into it. The candle is burning, which means oxygen has appeared, because. it is necessary for combustion.

We do the same experiment with the second jar, the candle goes out.

Conclusion:

The air in the jar with leaves, standing in the light, changed - oxygen appeared in it;

There were no changes in the second bank.

So, leaves produce oxygen in the light.

Here I have a question:If trees and shrubs shed their leaves in winter on a large part of the Earth, then why don’t we feel a lack of oxygen?

I continued my research.

2.2 Ways to utilize oxygen

While studying the role of oxygen in the atmosphere, I found out that the loss of molecular oxygen from the atmosphere occurs not only inas a result of breathing.

A person needs about 830 grams of oxygen per day to breathe, and 302.95 kg of oxygen per year. On average, one tree produces 2.5 kg of oxygen per day, and 912.5 kg of oxygen per year. It is known that 50 sq. m of green forest absorbs in 1 hour as much carbon dioxide as one person emits when breathing in 1 hour, i.e. 40 g.

The amount of carbon dioxide produced by all of Humanity (6 billion) in 1 day and the amount of carbon dioxide that can absorb the entire forest area (4 billion hectares):

50 m 2 x 24 hours = 1200 m 2 - S of forest required to absorb carbon dioxide produced by 1 person per day.

1200 x 6 billion = ha - S forests required to absorb carbon dioxide produced by all of Humanity in 1 day.

Calculations are approximate, because different sources give different data.

The estimated forest area on the planet is slightly more than 4 billion hectares, or 30% of the land area. But not all of these lands are occupied by trees - they also include clearings, roads, and clearings. Forests occupy about 3 billion hectares. More than 6 billion people live on the planet. When burning 1 kg of coal or wood, more than 2 kg of oxygen is consumed. This is approximately the oxygen produced by one tree.

One passenger car burns 1825 kg of oxygen for every 100 km of travel. This is approximately the oxygen produced by 734 trees. The combustion of 1 kg of gasoline requires about 300 kg of oxygen,

If you multiply these figures by the 400 million units of the global car fleet, you can imagine the extent of the threat hidden in excessive motorization.

A lot of oxygen is released by tropical forests, which are often called the “lungs of the planet.” At the same time, it is true that it is silent that during the year tropical forests consume almost as much oxygen as they produce. It is spent on the respiration of organisms that decompose finished organic matter, primarily bacteria and fungi.

Thus, about 60% of oxygen is spent, as is not surprising, not on the breathing of the inhabitants of our planet, but on the decomposition of dead organisms (rotting) and production activities person.

Conclusion: Oxygen not only gives us the opportunity to breathe deeply, but also acts as a kind of stove for burning garbage.

And so: in honorable 3rd place -our favorite forests!

Yes, there is an opinion that the “lungs of the planet” are forests, since it is believed that they are the main suppliers of oxygen to the atmosphere. However, in reality this is not the case.

No one argues that forests, of course, need to be preserved and protected. However, not at all due to the fact that they are these notorious “lungs”. Because in fact, their contribution to the enrichment of our atmosphere with oxygen is practically zero.

As we know, any tree is not eternal, so when the time comes, it dies. When the trunk of a forest giant falls to the ground, its body is decomposed by thousands of fungi and bacteria over a very long period of time. All of them use oxygen, which is produced by surviving plants. According to researchers' calculations, such "cleaning up" takes about eighty percent of the "forest" oxygen. But the remaining 20 percent of oxygen does not enter the “general atmospheric fund” at all, and is also used by forest inhabitants “on the ground” for their own purposes. After all, animals, plants, fungi and microorganisms also need to breathe. Since all forests are usually very densely populated areas, this residue is only enough to satisfy the oxygen needs of only its own inhabitants. There is nothing left for neighbors (for example, residents of cities where there is little native vegetation).

Who then is in 2nd place?

On land, these are, oddly enough, peat bogs.

Everyone knows that when plants die in a swamp, their organisms do not decompose, since the bacteria and fungi that do this work cannot live in swamp water - there are many natural antiseptics secreted by mosses.

So, dead parts of plants, without decomposing, sink to the bottom, forming peat deposits. And if there is no decomposition, then oxygen is not wasted. Therefore, swamps contribute about 50 percent of the oxygen they produce to the general fund (the other half is used by the inhabitants of these inhospitable, but very useful places).However, the contribution of swamps to the total " charitable foundation oxygen" is not very large, because there are not so many of them on Earth.

Microscopic ocean algae, the totality of which scientists call phytoplankton, are much more actively involved in “oxygen charity”.

These creatures are so small that it is almost impossible to see them with the naked eye.

However, their total quantity very large, the number goes into millions of billions. The entire world's phytoplankton produces 10 times more oxygen than it needs for breathing.

And 1st place is awarded to them!

As I expected, the excess evaporates into the atmosphere.

To test my assumption, I decided to conduct an experiment , for which I took aquatic plants with water from the aquarium and placed them in a jar along with small snails.

The candle burned in a closed jar for 15 seconds, having consumed the oxygen, it went out.

I covered the hole in the lid with plasticine and left the jar on the window.

In 2 days.

The snails remained alive, but the candle burned out for 5 seconds.

Conclusion:

Thanks to the plant, oxygen again appeared in the jar of water and carbon dioxide - some was used by the snails, and some was spent on combustion. This means that this is what happens in nature - gas exchange between the ocean and the atmosphere!

The entire surface of the World Ocean is in contact with the atmosphere. And it is natural that at the turn of these elements there is an intensive exchange between them. Gases, moisture and heat move in both directions. According to rough estimates, the plants of the World Ocean (covering an area of about 360 million km2) are capable of annually converting 20-155 billion tons of carbon into organic matter. At the same time, they use only 0.11% of solar energy falling on the Earth's surface.

As for the oxygen consumption for the decomposition of corpses, in the ocean they are very low - approximately 20 percent of the total production. This happens due to the fact that dead organisms are immediately eaten by scavengers, which sea water a great multitude live. Those, in turn, will be eaten by other scavengers after death, and so on, that is, corpses almost never lie in the water. The same remains, which are no longer of particular interest to anyone, fall to the bottom, where few people live, and there is simply no one to decompose them (this is how the well-known silt is formed), that is, in this case, oxygen is not consumed.

So, the World Ocean occupies 70% of the land and supplies to the atmosphere about 40 percent of the oxygen produced by phytoplankton. It is this reserve that is consumed in those areas where very little oxygen is produced. The latter, in addition to cities and villages, include deserts, steppes and meadows, as well as mountains.

The oceans not only enrich the atmosphere with oxygen, but also help remove carbon dioxide from it, which is formed as a result of the respiration of living organisms and as one of the consequences of the destruction of rocks and volcanic

activities.

Conclusion:

Oxygen dissolved in the waters of the World Ocean fully meets the needs of marine organisms; it also contributes to the oxidation of organic and mineral products.

excess oxygen evaporates into the atmosphere. It enters the atmosphere especially abundantly in places where marine plants grow, primarily unicellular planktonic algae.

The ocean removes excess carbon dioxide from the atmosphere.

Conclusion.

As is known, in the 21st century, as a result of the growth of cities and industrial enterprises, the land area occupied by green plants has sharply decreased. Forest areas are shrinking especially catastrophically. In this regard, the role of the ocean in the regeneration of the Earth’s air shell increases even more. So, oddly enough, the human race lives and thrives on Earth precisely due to the microscopic “oxygen factories” floating on the surface of the ocean. They should also be called “the lungs of the planet.” And protect in every possible way from oil pollution, heavy metal poisoning, etc., because if they suddenly stop their activities, you and I will simply have nothing to breathe.

References

Valerie Le Du "World of the Sea". Moscow: Makhaon, 2005.

Monin A S. History of the Earth. L.: Nauka, 1977..

Pimon M.R. “Secrets of the Sea.” Moscow: Makhaon, 2006.

Stepanov V.N. Nature of the World Ocean. M.: Education, 1982.

Tarasov V.I. "Hydrosphere": Tutorial. Ussuri State Pedagogical Institute, 2004.

World water balance and water resources Earth. L.: Gidrometeoizdat, 1974

World water balance and water resources of the Earth. L.: Gidrometeoizdat, 1974.

Encyclopedia of the connoisseur "Green Planet". Moscow, “Swallowtail”-2006

Encyclopedia for children. Moscow "Swallowtail" - 2013

Encyclopedia for schoolchildren. Moscow "Swallowtail" - 2011

Photosynthesis - Wikipedia.

World ocean - Wikipedia.

Oxygen - Wikipedia.

For one billion years, the Earth's atmosphere has consisted mainly of nitrogen (20–78%) and oxygen (5–21%). The modern atmosphere of the Earth in volume percentages contains: nitrogen - 78%, oxygen - 21, carbon dioxide - 0.03, argon - 0.93, the remaining 0.04% is occupied by helium, methane, krypton, nitrous oxide, hydrogen, xenon. The relatively high percentage of argon content in the atmosphere - 40 is explained by the fact that in the bowels of the Earth a large amount of radioactive potassium - 40 is converted into it. Modern physical parameters The atmosphere is as follows: the thickness of the atmospheric layer is up to 1000 kilometers, the mass is 5·10 18 kg, the pressure at the surface of the planet is 1 atmosphere.

The table shows evolutionary changes chemical composition of the atmosphere in the past and in the future 2 billion years into the future (in %). Let's look at the reasons for these changes in chemical composition Earth's atmosphere.

1 . Carbon dioxide CO2 is produced by massive volcanic eruptions. There is no consensus on its percentage composition in the atmosphere 4 - 5 billion years ago. The gas composition of modern volcanic eruptions contains 40% by weight carbon dioxide, and nitrogen N 2 - 2%. However, it can be assumed that in the past carbon dioxide had the ability to accumulate up to 90% in the atmosphere. This is because CO 2 and N 2 are the most inert chemical compounds atmosphere, and they almost do not react with other elements. The remaining volcanic gases (HCl, CN, HF, SO 2, NH 3 and others) are extremely aggressive components, therefore they were quickly “destroyed” by combining with rock metals and substances volcanic lava, salts dissolved in water. Consequently, the percentage of carbon dioxide and nitrogen constantly increased, and other gases gradually decreased.

It becomes clear how the carbon dioxide content in the atmosphere of the young Earth could increase to 90%, and the nitrogen content in our time has reached 78%. The main consumers of carbon dioxide are plants. Sources of carbon dioxide include volcanoes, industry and animal respiration. The main storage reservoirs are the atmosphere and the ocean.

A) The main “storage reservoirs” for carbon dioxide on Earth.

1) Now the atmosphere contains 0.03% carbon dioxide, which is 2·10 15 kilograms. At the same time, 10 16 kg of plants grow on Earth (according to A. Vinogradov), which absorb more than 10 14 kg of carbon dioxide per year. Then there will only be enough carbon dioxide for 20 years.

2) A large “reservoir” of carbon dioxide is the oceans and seas, since 5·10 16 kg of carbon dioxide are dissolved in their waters. Then only for 500 years flora The Earth could consume carbon dioxide dissolved in the hydrosphere. Carbon dioxide from the atmosphere still dissolves in large quantities in the waters of the oceans and seas. It is alarming that the percentage of carbon dioxide in the atmosphere will continue to decline in the future, and therefore its concentration in the ocean will also decrease.

B) The main sources of carbon dioxide on Earth.

1) Volcanic eruptions in the past, they were the most important source of carbon dioxide for the atmosphere, and plants were the only consumers of carbon dioxide. Currently, all volcanoes emit 10 9 kg of carbon dioxide into the atmosphere per year, and civilization burns organic fuels, and thereby also replenishes the atmosphere with carbon dioxide by another 3 10 12 kg per year (i.e. 3000 times more than volcanoes). Volcanic processes on the planet gradually die out as it “ages”. In 1 million years, volcanism on Earth will completely cease.

2) For about 150 years, an additional source of carbon dioxide will still operate - a civilization that large quantities burns fossil organic substances (coal, oil, firewood, oil shale - website). But then these minerals will be exhausted. Mineral deposits such as coal, oil, natural gas civilization will run out in 150 years, and civilization will stop replenishing the atmosphere with carbon dioxide produced by the combustion of fossil fuels. Therefore, some scientists believe that, despite burning fuel for 150 years, the percentage of carbon dioxide in the atmosphere will decrease. The amount of CO 2 will remain the same (0.03%), as it will be absorbed by plants and there will be a compensatory increase in biomass in the plants of the Earth. Other scientists talk about an increase in carbon dioxide content in the atmosphere to 0.04 - 0.05%, followed by a slight warming of the planet's climate by 2150. One way or another, after 2150 civilization will be left without organic fuel and the process of global reduction in the amount of carbon dioxide in the atmosphere will continue.

3) Carbon dioxide is also released into the atmosphere in the amount of 10 10 kg per year during the decomposition of dead animals and dead plants in the oceans, seas and on land. Carbon dioxide is also released from the lungs of animals and humans when they breathe.

C) The “rate” of the disappearance of carbon dioxide from the Earth’s atmosphere.

Let us pay attention to the fact that although over the past tens of millions of years everyone has been “working” natural springs carbon dioxide (volcanism, oceans, decay), but the content of carbon dioxide in the atmosphere decreased and, for example, over time Cenozoic era(over 70 million years) fell from 12% (before the start of the Cenozoic era) to 0.03%, that is, 400 times. In 10 million years, the amount of carbon dioxide in the atmosphere will decrease by 1000 times, the percentage composition will be 0.000003%. Such a decrease in carbon dioxide content has a detrimental effect on all plants, which is confirmed by experiments with placing plants under a glass bell and simultaneously reducing the CO 2 content there. Plants “ate” all the carbon dioxide in the atmosphere. Gas source food for plants has almost dried up. In response to this, plants will first (after 100 thousand years) be forced to reduce their own biomass hundreds of times, and, in the end, all plants will die from the lack of carbon dioxide in the atmosphere.

Carbon dioxide will be completely transformed by plants into oxygen in about 30 million years. Scientists believe that, thanks to the natural cycle of substances, carbon dioxide will not disappear from the earth’s atmosphere for almost 30 million years. Therefore, it can be argued that after 30 million years, due to the lack of carbon dioxide in the atmosphere, the complete extinction of the plant world will occur. It is clear that simultaneously with the disappearance of plants, the death of herbivores will occur. After this, predators will die out and the animal world will completely disappear. The Earth will lose all types of life for two geocosmic reasons: the disappearance of carbon dioxide from the atmosphere and severe cooling on the surface of the planet.

2 . Oxygen O2. Now we can formulate one of the main laws of biological evolution: the first type of living matter in the Universe are plants, which transform inorganic matter (CO 2) into organic (wood, leaves, fruits, flowers). The second type of living matter in the Universe is the animal world, which appears on the planet after the oceans and atmosphere are saturated with oxygen (O 2) during the life of plants, and plants and other animals serve as food for animals.

A) The main source of oxygen on Earth is plants.

After 3.5 billion years, when the first plants (algae) appeared in the ocean, the process of oxygen saturation of the atmosphere and ocean waters took place on Earth. In exchange for absorbing carbon dioxide, plants release oxygen into the atmosphere. Oxygen appeared in the atmosphere 3 billion years ago in an amount of 0.1 - 1%. He is very active chemicals. Therefore, in the past, about 10-20 kg of oxygen from the atmosphere was spent on the oxidation of atmospheric gases, substances dissolved in the oceans and seas, as well as on the oxidation of rock substances on land and at the bottom of the oceans. The entire modern plant world of the planet consumes 10 14 kg of carbon dioxide per year and releases 3·10 13 kg of oxygen, which is 3.3 times less than the mass of irretrievably absorbed carbon dioxide.

Therefore, we can conclude that currently the amount of oxygen in the atmosphere is increasing, and the amount of carbon dioxide is decreasing. If this process does not slow down, then in 1500 years there will be 26% oxygen in the atmosphere, in 3000 years - 42% (2 times more than now). But such a large increase in the percentage of oxygen in the atmosphere will not happen, since there is not enough carbon dioxide on the planet for this. On the surface of the Earth (in the atmosphere and oceans - site) there is approximately 10 17 kg of carbon dioxide, from which plants can obtain 3 10 16 kg of oxygen (3% of that in the atmosphere). Hence, maximum quantity oxygen in the atmosphere may increase to 24% (21% + 3%). At the current rate of oxygen release by plants, the atmosphere will contain 24% of it in several million years.

B) The main “reservoirs and storage facilities” of oxygen on Earth are the atmosphere and the ocean.

Now the amount of oxygen in the atmosphere is 21%, which is 10 18 kg by weight. About 3 times its mass is dissolved in the waters of oceans, seas, lakes and rivers. Fish breathe precisely this oxygen dissolved in water.

C) The main consumers of oxygen on Earth are the Earth's mantle, industry and animals.

1) Oxygen consumption for global oxidation. Water with oxygen dissolved in it penetrates deep into the bowels of the Earth, where oxygen reacts with the yet unoxidized substances of the crust and mantle. Water heated in the bowels of the Earth in the form of steam rises to the surface of the planet to cool and become saturated with a new portion of oxygen, and then sinks back into the bowels. Making countless circles, underground water per year carries about 10-11 kg of oxygen into the bowels of the Earth. The process of oxidation of substances in the bowels of the planet with oxygen dissolved in water is a fairly powerful source of its global consumption. The annual oxygen requirement for this geochemical process is 10 11 kg.

The entire mass of free oxygen in the atmosphere and ocean is approximately 3·10 18 kg. This means that the oxygen of the atmosphere and ocean will be spent on the oxidation of cooling rocks of the mantle and the substance of the Earth’s core 30 million years after the death of all plants on Earth (i.e., 60 million years from today). After the loss of oxygen, the atmosphere will consist exclusively of nitrogen. Therefore, in 60 million years, the Earth’s atmosphere will experience a nitrogen stage of evolutionary development.

2) Oxygen consumption for fuel combustion. Every year, 5·10 12 kg of atmospheric oxygen is spent by civilization on burning organic fuels and in fires (forest, oil wells, etc.). The end products of combustion are carbon dioxide and water.

Organic fuel + 3O 2 = CO 2 + 4H 2 O.

Plants almost immediately transform carbon dioxide (from burning fuels and fires) back into oxygen. Only oxygen is irretrievably lost during the synthesis of water during the combustion of organic substances, which amounts to 2·10 12 kg per year.

3) Atmospheric oxygen is consumed during the breathing of animals and people in an amount of about 10 9 kg per year. Carbon dioxide is exhaled from the lungs of animals and humans, which is quickly transformed by plants back into oxygen.

4) Conclusion about the rate of global oxygen absorption. If we sum up the mass of absorbed oxygen from the atmosphere and the mass of dissolved oxygen in the oceans, we get a value of about 6·10 12 kg per year. It is necessary to take into account that the irreversibly (irretrievably) mass of oxygen is absorbed in the amount of 3·10 12 kg per year, and the rest of its mass forms carbon dioxide and enters the cycle.

3 . Nitrogen N2, of which 78% (or about 4 10 18 kg) is now in the atmosphere, was formed for two reasons. Nitrogen is released into the atmosphere over 5 billion years due to volcanic processes. Volcanic gases contain from 0.1 to 2% nitrogen. Nitrogen gas has low chemical activity, so it constantly accumulates in the Earth's atmosphere. There is 5 times more nitrogen dissolved in the waters of oceans and seas than in the atmosphere - 20·10 18 kg. In total, the Earth's surface contains 24·10 18 kg of free nitrogen. In addition to volcanic origin, there are other mechanisms for the release of nitrogen into the atmosphere. Nitrogen entered the atmosphere during the oxidation of ammonia. Academician A. Vinogradov defends precisely this hypothesis of the appearance of nitrogen in the Earth’s atmosphere. According to rough estimates, from 5 to 2 billion years ago the Earth's atmosphere contained from 5 to 20% ammonia. Starting from the moment when plants began to release oxygen into the atmosphere, a global process of ammonia oxidation with the formation of nitrogen arose.

2NH 4 + 2O 2 = N 2 + 4H 2 O.

Nitrogen, unlike carbon dioxide and oxygen, does not participate in global biochemical processes. It is absorbed in small quantities per year by some types of azotobacteria in the soil and muddy bottom of water bodies. Nitrogen inside bacterial cells is converted into ammonia, cyanide compounds, nitrous oxide and nitrous oxide. Biologists have calculated that per year the atmosphere irreversibly loses 10–11 kg of nitrogen through microbiological processes. Then all the free nitrogen on Earth will be absorbed by bacteria in 240 million years.

There is an opinion that the “lungs of the planet” are forests, since it is believed that they are the main suppliers of oxygen to the atmosphere. However, in reality this is not the case. The main producers of oxygen live in the ocean. These babies cannot be seen without the help of a microscope. But all living organisms on Earth depend on their livelihoods.

No one will deny the fact that the oxygen atmosphere of the Earth was created and continues to be maintained by plants. This happened because they learned to create organic matter from inorganic ones, using the energy of sunlight (as we remember from school course biology, a similar process is called photosynthesis). As a result of this process, plant leaves release free oxygen as a by-product of production. This gas, which we need, rises into the atmosphere and is then evenly distributed throughout it.

According to various institutes, thus, about 145 billion tons of oxygen are released into the atmosphere on our planet every year. Moreover, most of it is spent, not surprisingly, not on the respiration of the inhabitants of our planet, but on the decomposition of dead organisms or, simply put, on decay (about 60 percent of that used by living beings). So, as you can see, oxygen not only gives us the opportunity to breathe deeply, but also acts as a kind of stove for burning garbage.

Read also: The winter-summer air conditioner on Earth has broken downAs we know, any tree is not eternal, so when the time comes, it dies. When the trunk of a forest giant falls to the ground, its body is decomposed by thousands of fungi and bacteria over a very long period of time. All of them use oxygen, which is produced by surviving plants. According to researchers' calculations, such "cleaning up" takes about eighty percent of the "forest" oxygen.

But the remaining 20 percent of oxygen does not enter the “general atmospheric fund” at all, and is also used by forest inhabitants “on the ground” for their own purposes. After all, animals, plants, fungi and microorganisms also need to breathe (without oxygen, as we remember, many living beings would not be able to obtain energy from food). Since all forests are usually very densely populated areas, this residue is only enough to satisfy the oxygen needs of only its own inhabitants. There is nothing left for neighbors (for example, residents of cities where there is little native vegetation).

Who, then, is the main supplier of this gas necessary for breathing on our planet? On land these are, oddly enough... peat bogs. Everyone knows that when plants die in a swamp, their organisms do not decompose, since the bacteria and fungi that do this work cannot live in swamp water - there are many natural antiseptics secreted by mosses.

Nevertheless, the contribution of swamps to the general “charitable oxygen fund” is not very large, because there are not so many of them on Earth. Microscopic ocean algae, the totality of which scientists call phytoplankton, are much more actively involved in “oxygen charity”. These creatures are so small that it is almost impossible to see them with the naked eye. However, their total number is very large, amounting to millions of billions.So, dead parts of plants, without decomposing, sink to the bottom, forming peat deposits. And if there is no decomposition, then oxygen is not wasted. Therefore, swamps contribute about 50 percent of the oxygen they produce to the general fund (the other half is used by the inhabitants of these inhospitable, but very useful places).

The entire world's phytoplankton produces 10 times more oxygen than it needs for breathing. Enough to provide useful gas and all other inhabitants of the waters, and a lot gets into the atmosphere. As for the oxygen consumption for the decomposition of corpses, in the ocean they are very low - approximately 20 percent of the total production.

This happens due to the fact that dead organisms are immediately eaten by scavengers, of which there are a great many living in sea water. Those, in turn, will be eaten by other scavengers after death, and so on, that is, corpses almost never lie in the water. The same remains, which are no longer of particular interest to anyone, fall to the bottom, where few people live, and there is simply no one to decompose them (this is how the well-known silt is formed), that is, in this case, oxygen is not consumed.

So, the ocean supplies the atmosphere with about 40 percent of the oxygen that phytoplankton produced. It is this reserve that is consumed in those areas where very little oxygen is produced. The latter, in addition to cities and villages, include deserts, steppes and meadows, as well as mountains.

So, oddly enough, the human race lives and thrives on Earth precisely due to the microscopic “oxygen factories” floating on the surface of the ocean. It is they who should be called “the lungs of the planet.” And protect in every possible way from oil pollution, heavy metal poisoning, etc., because if they suddenly stop their activities, you and I will simply have nothing to breathe.