lesson type - combined
Methods: partially exploratory, problem presentation, reproductive, explanatory-illustrative.
Target:
Students' awareness of the importance of all the issues discussed, the ability to build their relationship with nature and society based on respect for life, for all living things as a unique and priceless part of the biosphere;
Tasks:
Educational: to show the multiplicity of factors acting on organisms in nature, the relativity of the concept of "harmful and beneficial factors", the diversity of life on planet Earth and the options for adapting living beings to the whole range of environmental conditions.
Developing: develop communication skills, the ability to independently acquire knowledge and stimulate their cognitive activity; the ability to analyze information, highlight the main thing in the studied material.
Educational:
To cultivate a culture of behavior in nature, the qualities of a tolerant person, to instill interest and love for wildlife, to form a stable positive attitude towards every living organism on Earth, to form the ability to see beauty.
Personal: cognitive interest in ecology. Understanding the need to gain knowledge about the diversity of biotic relationships in natural communities in order to preserve natural biocenoses. The ability to choose the target and semantic settings in their actions and deeds in relation to wildlife. The need for fair evaluation of one's own work and the work of classmates
cognitive: the ability to work with various sources of information, convert it from one form to another, compare and analyze information, draw conclusions, prepare messages and presentations.
Regulatory: the ability to organize independently the execution of tasks, evaluate the correctness of the work, reflection of their activities.
Communicative: participate in the dialogue in the classroom; answer questions from a teacher, classmates, speak to an audience using multimedia equipment or other means of demonstration
Planned results
Subject: know - the concepts of "habitat", "ecology", "environmental factors" their influence on living organisms, "connections of living and non-living";. Be able to - define the concept of "biotic factors"; characterize biotic factors, give examples.
Personal: make judgments, search and select information; analyze connections, compare, find an answer to a problematic question
Metasubject: connections with such academic disciplines as biology, chemistry, physics, geography. Plan actions with a set goal; find the necessary information in the textbook and reference literature; to carry out the analysis of objects of nature; draw conclusions; formulate your own opinion.
Form of organization learning activities - individual, group
Teaching methods: visual and illustrative, explanatory and illustrative, partially exploratory, independent work with additional literature and textbook, with DER.
Receptions: analysis, synthesis, conclusion, transfer of information from one type to another, generalization.
Learning new material
Organisms living on the surface of the Earth are surrounded by a gaseous environment characterized by low humidity, density and pressure, as well as a high content of oxygen. The environmental factors operating in the ground-air environment differ in a number of specific features: compared to other environments, the light here is more intense, the temperature undergoes stronger fluctuations, and the humidity varies significantly depending on the geographical location, season and time of day. The impact of almost all these factors is closely related to the movement of air masses - winds.
In the course of evolution, the inhabitants of the ground-air environment have developed specific anatomical, morphological, physiological, behavioral and other adaptations. They have organs that provide direct assimilation atmospheric air in the process of respiration (stomata of plants, lungs and tracheas of animals); skeletal formations that support the body in conditions of low density of the medium have received strong development
(mechanical and supporting tissues of plants, animal skeleton); you have worked out complex adaptations for protection against adverse factors (periodicity and rhythm of life cycles, the complex structure of integuments, thermoregulation mechanisms, etc.); established over close connection with soil (plant roots); you-worked great mobility of animals in search of food; flying animals and airborne fruits, seeds, pollen of plants appeared.
Let us consider the main abiotic factors in the ground-air environment of life.
Air.
Dry air at sea level is composed (by volume) of 78% nitrogen, 21% oxygen, 0.03% carbon dioxide; at least 1% is accounted for by inert gases.
Oxygen is necessary for the respiration of the vast majority of organisms, carbon dioxide is used by plants during photosynthesis. The movement of air masses (wind) changes the temperature and humidity of the air, has a mechanical effect on organisms. Wind causes a change in transpiration in plants. This is especially pronounced during dry winds, which dry up the air and often cause the death of plants. The wind plays a significant role in the pollination of anemophiles - wind-pollinated plants. Winds determine the direction of migration of insects such as meadow moth, desert locust, malarial mosquitoes.
Precipitation.
Precipitation in the form of rain, snow or hail changes the humidity of the air and soil, provides plants with available moisture, gives drinking water animals. Heavy rains can cause floods, temporarily flood a particular area. Showers, and especially hail, often lead to mechanical damage to the vegetative organs of plants.
Of great importance for the water regime are the timing of rainfall, their frequency and duration. The nature of the rain is also important. During heavy rains, the soil does not have time to absorb water. This water drains quickly, and its strong currents often carry part of the fertile soil layer into rivers and lakes, and with it weakly rooted plants, and sometimes small animals. Drizzling rains, on the contrary, moisten the soil well, however, if they drag on, waterlogging occurs.
Precipitation in the form of snow has a beneficial effect on organisms in winter period time. Being a good insulator, snow protects the soil and vegetation from freezing (a layer of snow of 20 cm protects the plant at an air temperature of -25 ° C), and serves as a shelter for small animals, where they find food and more suitable temperature conditions. In severe frosts, black grouse, partridges, hazel grouses hide under the snow. However, during snowy winters, there is a mass death of some animals, for example, roe deer and wild boar: With heavy snow cover, it is difficult for them to move and forage.
Soil moisture.
Soil water is one of the main sources of moisture for plants. According to its physical state, mobility, availability and significance for plants, soil water is divided into free, capillary, chemically and physically bound.
The main variety of free water is gravitational water. It fills the wide gaps between the soil particles and, under the influence of gravity, constantly goes into deeper layers until it reaches the impermeable layer. Plants easily assimilate it while it is in the zone of the root system.
Capillary water fills the thinnest gaps between soil particles, it is also well absorbed by plants. It is held in the capillaries by cohesion. Under the influence of evaporation from the soil surface, capillary water forms an upward current, in contrast to gravitational water, which is characterized by a downward current. These movements of water, its consumption depend on air temperature, relief features, soil properties, vegetation cover, wind strength and other factors. Both capillary and gravitational water are so-called plant-available water.
The soil also contains chemically and physically bound water contained in some soil minerals (opal, gypsum, montrillonite, hydromica, etc.). All this water is absolutely inaccessible to plants, although in some soils (clay, peat) its content very large.
♦ Ecoclimate.
Each habitat is characterized by a certain ecological climate - ecoclimate, i.e., the climate of the surface layer of air. Big influence Vegetation influences climatic factors. Under the forest canopy, for example, air humidity is always higher, and temperature fluctuations are less than in glades. The light regime of these places is also different. In different plant associations, their own regime of humidity, temperature, and light is formed. Then they talk about phytoclimate.
The living conditions surrounding insect larvae living under the bark of a tree are different from those in the forest where this tree grows. In this case, the temperature of the southern side of the trunk can be 10-15°C higher than the temperature of its northern side. Such small areas of habitat have their own microclimate. Special micro-climatic conditions are created not only by plants, but also by animals. A stable microclimate is possessed by inhabited animal burrows, tree hollows, and caves.
For the ground-air environment, as well as for the water, a clearly defined zoning is characteristic. There are latitudinal and meridional, or longitudinal, natural zones. The first stretch from west to east, the second - from north to south.
Questions and tasks
1. Describe the main abiotic factors of the ground-air environment.
2. Give examples of the inhabitants of the ground-air environment.
Features of the ground-air environment of habitation. In the ground-air environment, there is enough light and air. But humidity and air temperature are very diverse. In swampy areas there is an excessive amount of moisture, in the steppes it is much less. There are also daily and seasonal fluctuations in temperature.
Adaptation of organisms to life in conditions of different temperatures and humidity. A large number of adaptations of organisms of the ground-air environment is associated with temperature and humidity. Animals of the steppe (scorpions, tarantula and karakurt spiders, ground squirrels, mice, voles) hide from the heat in burrows. Plants are protected from hot sunlight by increased evaporation of water from the leaves. In animals, this adaptation is the release of sweat.
With the onset of cold weather, birds fly away to warmer climes in order to return again in the spring to the place where they were born and where they will give birth. A feature of the ground-air environment in the southern regions of Ukraine or in the Crimea is an insufficient amount of moisture.
Familiarize yourself with fig. 151 with plants that have adapted to similar conditions.
Adaptation of organisms to movement in the ground-air environment. For many animals of the ground-air environment, it is important to move along the earth's surface or in the air. To do this, they have certain adaptations, and their limbs have a different structure. Some have adapted to running (wolf, horse), others to jumping (kangaroo, jerboa, grasshopper), others to flight (birds, bats, insects) (Fig. 152). Snakes, vipers do not have limbs. They move by bending the body.
Much fewer organisms have adapted to life high in the mountains, since there is little soil, moisture and air for plants, and animals have difficulty moving. But some animals, such as mountain goats moufflons (Fig. 154), are able to move almost vertically up and down if there are even slight irregularities. Therefore, they can live high in the mountains. material from the site
Adaptation of organisms to different lighting conditions. One of the adaptations of plants to different lighting is the direction of the leaves to the light. In the shade, the leaves are arranged horizontally: this way they get more light rays. Light-loving snowdrop and ryast develop and bloom in early spring. During this period, they have enough light, since the leaves on the trees in the forest have not yet appeared.
Adaptation of animals to the specified factor of the ground-air habitat - the structure and size of the eyes. In most animals of this environment, the organs of vision are well developed. For example, a hawk from the height of its flight sees a mouse running across the field.
Over many centuries of development, the organisms of the ground-air environment have adapted to the influence of its factors.
Didn't find what you were looking for? Use the search
On this page, material on the topics:
- report on the topic of the habitat of a living organism Grade 6
- adaptability of the snowy owl to the environment
- terms on the topic air environment
- report on terrestrial air habitat
- adaptation of birds of prey to their environment
In the ground-air environment, the operating environmental factors have a number of characteristic features: higher light intensity in comparison with other media, significant temperature fluctuations, changes in humidity depending on geographical location, season and time of day. The impact of the factors listed above is inextricably linked with the movement of air masses - the wind.
In the process of evolution, living organisms of the terrestrial-air environment have developed characteristic anatomical, morphological, physiological, behavioral and other adaptations. Let us consider the features of the impact of the main environmental factors on plants and animals in the ground-air environment of life.
The low air density determines its low lifting force and insignificant bearing capacity. All inhabitants of the air environment are closely connected with the surface of the earth, which serves them for attachment and support. For most organisms, staying in the air is associated only with dispersal or the search for prey. The small lifting force of air determines the limiting mass and size of terrestrial organisms. The largest animals living on the surface of the earth are smaller than the giants of the aquatic environment.
Low air density creates a slight resistance to movement. The ecological benefits of this property of the air environment have been used by many terrestrial animals in the course of evolution, acquiring the ability to fly: 75% of all species of terrestrial animals are capable of active flight.
Due to the mobility of the air that exists in the lower layers of the atmosphere, the vertical and horizontal movement of air masses, passive flight of certain types of organisms is possible, anemochory is developed - settlement with the help of air currents. Wind pollinated plants have a number of adaptations that improve the aerodynamic properties of pollen.
Their flower covers are usually reduced and the anthers are not protected from the wind. In the resettlement of plants, animals and microorganisms, the main role is played by vertical convection air currents and weak winds. Storms and hurricanes have a significant environmental impact on terrestrial organisms.
In areas where strong winds are constantly blowing, as a rule, the species composition of small flying animals is poor, since they are not able to resist powerful air currents. The wind causes a change in the intensity of transpiration in plants, which is especially pronounced during dry winds that dry up the air, and can lead to the death of plants. The main ecological role of horizontal air movements (winds) is indirect and consists in strengthening or weakening the impact on terrestrial organisms of such important ecological factors like temperature and humidity.
Saint Petersburg State Academy
Veterinary medicine.
Department of General Biology, Ecology and Histology.
Abstract on ecology on the topic:
Ground-air environment, its factors
and adaptation of organisms to them
Completed by: 1st year student
Oh group Pyatochenko N. L.
Checked by: Associate Professor of the Department
Vakhmistrova S. F.
St. Petersburg
Introduction
The conditions of life (conditions of existence) are a set of elements necessary for the body, with which it is inextricably linked and without which it cannot exist.
The adaptations of an organism to its environment are called adaptations. The ability to adapt is one of the main properties of life in general, providing the possibility of its existence, survival and reproduction. Adaptation manifests itself at different levels - from the biochemistry of cells and the behavior of individual organisms to the structure and functioning of communities and ecosystems. Adaptations arise and change during the evolution of a species.
Separate properties or elements of the environment that affect organisms are called environmental factors. Environmental factors are varied. They have different nature and specific action. Environmental factors are divided into two large groups: abiotic and biotic.
Abiotic factors- this is a complex of conditions of the inorganic environment that affect living organisms directly or indirectly: temperature, light, radiation, pressure, air humidity, salt composition of water, etc.
Biotic factors are all forms of influence of living organisms on each other. Each organism constantly experiences the direct or indirect influence of others, entering into communication with representatives of its own and other species.
In some cases, anthropogenic factors are separated into an independent group along with biotic and abiotic factors, emphasizing the extraordinary effect of the anthropogenic factor.
Anthropogenic factors are all forms of activity of human society that lead to a change in nature as a habitat for other species or directly affect their lives. The importance of anthropogenic impact on the entire living world of the Earth continues to grow rapidly.
Changes in environmental factors over time can be:
1) regular-constant, changing the strength of the impact in connection with the time of day, the season of the year or the rhythm of the tides in the ocean;
2) irregular, without a clear periodicity, for example, changes in weather conditions in different years, storms, downpours, mudflows, etc.;
3) directed over certain or long periods of time, for example, cooling or warming of the climate, overgrowing of a reservoir, etc.
Environmental factors can have various effects on living organisms:
1) as irritants, causing adaptive changes in physiological and biochemical functions;
2) as constraints, causing the impossibility of existence in the data
conditions;
3) as modifiers causing anatomical and morphological changes in organisms;
4) as signals indicating a change in other factors.
Despite the wide variety of environmental factors, a number of general patterns can be distinguished in the nature of their interaction with organisms and in the responses of living beings.
The intensity of the environmental factor, the most favorable for the life of the organism, is the optimum, and giving the worst effect is the pessimum, i.e. conditions under which the vital activity of the organism is maximally inhibited, but it can still exist. So, when growing plants in different temperature conditions, the point at which maximum growth is observed will be the optimum. In most cases, this is a certain temperature range of several degrees, so here it is better to talk about the optimum zone. The entire temperature range (from minimum to maximum), at which growth is still possible, is called the range of stability (endurance), or tolerance. The point limiting its (i.e. minimum and maximum) habitable temperatures is the limit of stability. Between the optimum zone and the stability limit, as the latter is approached, the plant experiences increasing stress, i.e. we are talking about stress zones, or zones of oppression, within the range of stability
Dependence of the action of the environmental factor on its intensity (according to V.A. Radkevich, 1977)
As the scale moves up and down, not only does stress increase, but ultimately, upon reaching the limits of the organism's resistance, its death occurs. Similar experiments can be carried out to test the influence of other factors. The results will graphically follow a similar type of curve.
Ground-air environment of life, its characteristics and forms of adaptation to it.
Life on land required such adaptations that were possible only in highly organized living organisms. The ground-air environment is more difficult for life, it is characterized by a high oxygen content, a small amount of water vapor, low density, etc. This greatly changed the conditions of respiration, water exchange and movement of living beings.
The low air density determines its low lifting force and insignificant bearing capacity. Air organisms must have their own support system that supports the body: plants - a variety of mechanical tissues, animals - a solid or hydrostatic skeleton. In addition, all the inhabitants of the air environment are closely connected with the surface of the earth, which serves them for attachment and support.
Low air density provides low movement resistance. Therefore, many land animals have acquired the ability to fly. 75% of all terrestrial creatures, mainly insects and birds, have adapted to active flight.
Due to the mobility of air, the vertical and horizontal flows of air masses existing in the lower layers of the atmosphere, passive flight of organisms is possible. In this regard, many species have developed anemochory - resettlement with the help of air currents. Anemochory is characteristic of spores, seeds and fruits of plants, protozoan cysts, small insects, spiders, etc. Organisms passively transported by air currents are collectively called aeroplankton.
Terrestrial organisms exist in conditions of relatively low pressure due to the low density of air. Normally, it is equal to 760 mm Hg. As altitude increases, pressure decreases. Low pressure may limit the distribution of species in the mountains. For vertebrates, the upper limit of life is about 60 mm. A decrease in pressure entails a decrease in oxygen supply and dehydration of animals due to an increase in the respiratory rate. Approximately the same limits of advance in the mountains have higher plants. Somewhat more hardy are the arthropods that can be found on glaciers above the vegetation line.
Gas composition of air. In addition to the physical properties of the air environment, its chemical properties are very important for the existence of terrestrial organisms. The gas composition of air in the surface layer of the atmosphere is quite homogeneous in terms of the content of the main components (nitrogen - 78.1%, oxygen - 21.0%, argon 0.9%, carbon dioxide - 0.003% by volume).
The high oxygen content contributed to an increase in the metabolism of terrestrial organisms compared to primary aquatic ones. It was in the terrestrial environment, on the basis of the high efficiency of oxidative processes in the body, that animal homeothermia arose. Oxygen, due to its constant high content in the air, is not a limiting factor for life in the terrestrial environment.
The content of carbon dioxide can vary in certain areas of the surface layer of air within fairly significant limits. Increased air saturation with CO? occurs in zones of volcanic activity, near thermal springs and other underground outlets of this gas. In high concentrations, carbon dioxide is toxic. In nature, such concentrations are rare. Low CO2 content slows down the process of photosynthesis. Under indoor conditions, you can increase the rate of photosynthesis by increasing the concentration of carbon dioxide. This is used in the practice of greenhouses and greenhouses.
Air nitrogen for most inhabitants of the terrestrial environment is an inert gas, but individual microorganisms (nodule bacteria, nitrogen bacteria, blue-green algae, etc.) have the ability to bind it and involve it in the biological cycle of substances.
Moisture deficiency is one of the essential features of the ground-air environment of life. The whole evolution of terrestrial organisms was under the sign of adaptation to the extraction and conservation of moisture. The modes of environmental humidity on land are very diverse - from the complete and constant saturation of air with water vapor in some areas of the tropics to their almost complete absence in the dry air of deserts. The daily and seasonal variability of water vapor content in the atmosphere is also significant. The water supply of terrestrial organisms also depends on the mode of precipitation, the presence of reservoirs, soil moisture reserves, the proximity of groundwater, and so on.
This led to the development in terrestrial organisms of adaptation to different regimes water supply.
Temperature regime. Next hallmark air-ground environment are significant temperature fluctuations. In most land areas, daily and annual temperature amplitudes are tens of degrees. The resistance to temperature changes in the environment of terrestrial inhabitants is very different, depending on the particular habitat in which they live. However, in general, terrestrial organisms are much more eurythermic than aquatic organisms.
The conditions of life in the ground-air environment are complicated, in addition, by the existence of weather changes. Weather - continuously changing states of the atmosphere near the borrowed surface, up to a height of about 20 km (troposphere boundary). Weather variability is manifested in the constant variation of the combination of such environmental factors as temperature, air humidity, cloudiness, precipitation, wind strength and direction, etc. The long-term weather regime characterizes the climate of the area. The concept of "Climate" includes not only the average values of meteorological phenomena, but also their annual and daily course, deviation from it and their frequency. The climate is determined by the geographical conditions of the area. The main climatic factors - temperature and humidity - are measured by the amount of precipitation and the saturation of the air with water vapor.
For most terrestrial organisms, especially small ones, the climate of the area is not so much important as the conditions of their immediate habitat. Very often, local elements of the environment (relief, exposition, vegetation, etc.) change the regime of temperatures, humidity, light, air movement in a particular area in such a way that it differs significantly from the climatic conditions of the area. Such modifications of the climate, which take shape in the surface layer of air, are called the microclimate. In each zone, the microclimate is very diverse. Microclimates of very small areas can be distinguished.
The light regime of the ground-air environment also has some features. The intensity and amount of light here are the greatest and practically do not limit the life of green plants, as in water or soil. On land, the existence of extremely photophilous species is possible. For the vast majority of terrestrial animals with diurnal and even nocturnal activity, vision is one of the main ways of orientation. In terrestrial animals, vision is essential for finding prey, and many species even have color vision. In this regard, the victims develop such adaptive features as a defensive reaction, masking and warning coloration, mimicry, etc.
In aquatic life, such adaptations are much less developed. The emergence of brightly colored flowers of higher plants is also associated with the peculiarities of the apparatus of pollinators and, ultimately, with the light regime of the environment.
The relief of the terrain and the properties of the soil are also the conditions for the life of terrestrial organisms and, first of all, plants. The properties of the earth's surface that have an ecological impact on its inhabitants are united by "edaphic environmental factors" (from the Greek "edafos" - "soil").
In relation to different soil properties, one can distinguish whole line ecological groups of plants. So, according to the reaction to the acidity of the soil, they distinguish:
1) acidophilic species - grow on acidic soils with a pH of at least 6.7 (plants of sphagnum bogs);
2) neutrophils tend to grow on soils with a pH of 6.7–7.0 (most cultivated plants);
3) basiphilic grow at a pH of more than 7.0 (mordovnik, forest anemone);
4) indifferent ones can grow on soils with different pH values (lily of the valley).
Plants also differ in relation to soil moisture. Certain species are confined to different substrates, for example, petrophytes grow on stony soils, and pasmophytes inhabit free-flowing sands.
The terrain and the nature of the soil affect the specifics of the movement of animals: for example, ungulates, ostriches, bustards living in open spaces, hard ground, to enhance repulsion when running. In lizards that live in loose sands, the fingers are fringed with horny scales that increase support. For terrestrial inhabitants digging holes, dense soil is unfavorable. The nature of the soil in certain cases affects the distribution of terrestrial animals that dig holes or burrow into the ground, or lay eggs in the soil, etc.
On the composition of air.
The gas composition of the air we breathe is 78% nitrogen, 21% oxygen and 1% other gases. But in the atmosphere of large industrial cities, this ratio is often violated. A significant proportion is made up of harmful impurities caused by emissions from enterprises and vehicles. Motor transport brings many impurities into the atmosphere: hydrocarbons of unknown composition, benzo (a) pyrene, carbon dioxide, sulfur and nitrogen compounds, lead, carbon monoxide.
The atmosphere consists of a mixture of a number of gases - air, in which colloidal impurities are suspended - dust, droplets, crystals, etc. The composition of atmospheric air changes little with height. However, starting from a height of about 100 km, along with molecular oxygen and nitrogen, atomic oxygen also appears as a result of the dissociation of molecules, and the gravitational separation of gases begins. Above 300 km, atomic oxygen predominates in the atmosphere, above 1000 km - helium and then atomic hydrogen. The pressure and density of the atmosphere decrease with height; about half of the total mass of the atmosphere is concentrated in the lower 5 km, 9/10 - in the lower 20 km and 99.5% - in the lower 80 km. At altitudes of about 750 km, the air density drops to 10-10 g/m3 (whereas near the earth's surface it is about 103 g/m3), but even such a low density is still sufficient for the occurrence of auroras. The atmosphere does not have a sharp upper boundary; the density of its constituent gases
The composition of the atmospheric air that each of us breathes includes several gases, the main of which are: nitrogen (78.09%), oxygen (20.95%), hydrogen (0.01%) carbon dioxide (carbon dioxide) (0.03%) and inert gases (0.93%). In addition, there is always a certain amount of water vapor in the air, the amount of which always changes with temperature: the higher the temperature, the greater the vapor content and vice versa. Due to fluctuations in the amount of water vapor in the air, the percentage of gases in it is also variable. All gases in air are colorless and odorless. The weight of air varies depending not only on temperature, but also on the content of water vapor in it. At the same temperature, the weight of dry air is greater than that of moist air, because water vapor is much lighter than air vapor.
The table shows the gas composition of the atmosphere in volumetric mass ratio, as well as the lifetime of the main components:
| Component | % by volume | % mass |
| N2 | 78,09 | 75,50 |
| O2 | 20,95 | 23,15 |
| Ar | 0,933 | 1,292 |
| CO2 | 0,03 | 0,046 |
| Ne | 1,8 10-3 | 1,4 10-3 |
| He | 4,6 10-4 | 6,4 10-5 |
| CH4 | 1,52 10-4 | 8,4 10-5 |
| kr | 1,14 10-4 | 3 10-4 |
| H2 | 5 10-5 | 8 10-5 |
| N2O | 5 10-5 | 8 10-5 |
| Xe | 8,6 10-6 | 4 10-5 |
| O3 | 3 10-7 - 3 10-6 | 5 10-7 - 5 10-6 |
| Rn | 6 10-18 | 4,5 10-17 |
The properties of the gases that make up atmospheric air change under pressure.
For example: oxygen under pressure of more than 2 atmospheres has a toxic effect on the body.
Nitrogen under pressure over 5 atmospheres has a narcotic effect (nitrogen intoxication). A rapid rise from the depth causes decompression sickness due to the rapid release of nitrogen bubbles from the blood, as if foaming it.
An increase in carbon dioxide of more than 3% in the respiratory mixture causes death.
Each component that is part of the air, with an increase in pressure to certain limits, becomes a poison that can poison the body.
Studies of the gas composition of the atmosphere. atmospheric chemistry
For the history of the rapid development of a relatively young branch of science called atmospheric chemistry, the term “spurt” (throw) used in high-speed sports is most suitable. The shot from the starting pistol, perhaps, was two articles published in the early 1970s. They dealt with the possible destruction of stratospheric ozone by nitrogen oxides - NO and NO2. The first belonged to the future Nobel laureate, and then an employee of the Stockholm University, P. Krutzen, who considered the probable source of nitrogen oxides in the stratosphere to be naturally occurring nitrous oxide N2O that decays under the action of sunlight. The author of the second article, G. Johnston, a chemist from the University of California at Berkeley, suggested that nitrogen oxides appear in the stratosphere as a result of human activity, namely, from the emissions of combustion products from jet engines of high-altitude aircraft.
Of course, the above hypotheses did not arise from scratch. The ratio of at least the main components in the atmospheric air - molecules of nitrogen, oxygen, water vapor, etc. - was known much earlier. Already in the second half of the XIX century. in Europe, measurements of ozone concentration in surface air were made. In the 1930s, the English scientist S. Chapman discovered the mechanism of ozone formation in a purely oxygen atmosphere, indicating a set of interactions of oxygen atoms and molecules, as well as ozone in the absence of any other air components. However, in the late 1950s, meteorological rocket measurements showed that there was much less ozone in the stratosphere than it should be according to the Chapman reaction cycle. Although this mechanism remains fundamental to this day, it has become clear that there are some other processes that are also actively involved in the formation of atmospheric ozone.
It is worth mentioning that by the beginning of the 1970s, knowledge in the field of atmospheric chemistry was mainly obtained through the efforts of individual scientists, whose research was not united by any socially significant concept and was most often purely academic in nature. Another thing is the work of Johnston: according to his calculations, 500 aircraft, flying 7 hours a day, could reduce the amount of stratospheric ozone by at least 10%! And if these assessments were fair, then the problem would immediately become a socio-economic one, since in this case all programs for the development of supersonic transport aviation and related infrastructure would have to undergo a significant adjustment, and perhaps even closure. In addition, then for the first time the question really arose that anthropogenic activity could cause not a local, but a global cataclysm. Naturally, in the current situation, the theory needed a very tough and at the same time prompt verification.
Recall that the essence of the above hypothesis was that nitric oxide reacts with ozone NO + O3 ® ® NO2 + O2, then the nitrogen dioxide formed in this reaction reacts with the oxygen atom NO2 + O ® NO + O2, thereby restoring the presence NO in the atmosphere, while the ozone molecule is irretrievably lost. In this case, such a pair of reactions, constituting the nitrogen catalytic cycle of ozone destruction, is repeated until any chemical or physical processes lead to the removal of nitrogen oxides from the atmosphere. So, for example, NO2 is oxidized to nitric acid HNO3, which is highly soluble in water, and therefore is removed from the atmosphere by clouds and precipitation. The nitrogen catalytic cycle is very efficient: one NO molecule manages to destroy tens of thousands of ozone molecules during its stay in the atmosphere.
But, as you know, trouble does not come alone. Soon, specialists from US universities - Michigan (R. Stolyarsky and R. Cicerone) and Harvard (S. Wofsi and M. McElroy) - discovered that ozone could have an even more merciless enemy - chlorine compounds. According to their estimates, the chlorine catalytic cycle of ozone destruction (reactions Cl + O3 ® ClO + O2 and ClO + O ® Cl + O2) was several times more efficient than the nitrogen one. The only reason for cautious optimism was that the amount of naturally occurring chlorine in the atmosphere is relatively small, which means that the overall effect of its impact on ozone may not be too strong. However, the situation changed dramatically when, in 1974, employees of the University of California at Irvine, S. Rowland and M. Molina, found that the source of chlorine in the stratosphere is chlorofluorohydrocarbon compounds (CFCs), which are widely used in refrigeration units, aerosol packages, etc. Being non-flammable, non-toxic and chemically passive, these substances are slowly transported by ascending air currents from the earth's surface to the stratosphere, where their molecules are destroyed by sunlight, resulting in the release of free chlorine atoms. The industrial production of CFCs, which began in the 1930s, and their emissions into the atmosphere steadily increased in all subsequent years, especially in the 70s and 80s. Thus, within a very short period of time, theorists have identified two problems in atmospheric chemistry caused by intense anthropogenic pollution.
However, in order to test the viability of the proposed hypotheses, it was necessary to perform many tasks.
First of all, expand laboratory research, during which it would be possible to determine or clarify the rates of photochemical reactions between various components of atmospheric air. It must be said that the very meager data on these velocities that existed at that time also had a fair (up to several hundred percent) errors. In addition, the conditions under which the measurements were made, as a rule, did not correspond much to the realities of the atmosphere, which seriously aggravated the error, since the intensity of most reactions depended on temperature, and sometimes on pressure or atmospheric air density.
Secondly, intensively study the radiation-optical properties of a number of small atmospheric gases in laboratory conditions. Molecules of a significant number of components of atmospheric air are destroyed by the ultraviolet radiation of the Sun (in photolysis reactions), among them are not only the CFCs mentioned above, but also molecular oxygen, ozone, nitrogen oxides and many others. Therefore, estimates of the parameters of each photolysis reaction were just as necessary and important for the correct reproduction of atmospheric chemical processes as were the rates of reactions between different molecules.
Thirdly, it was necessary to create mathematical models capable of describing the mutual chemical transformations of atmospheric air components as fully as possible. As already mentioned, the productivity of ozone destruction in catalytic cycles is determined by how long the catalyst (NO, Cl, or some other) stays in the atmosphere. It is clear that such a catalyst, generally speaking, could react with any of the dozens of atmospheric air components, quickly degrading in the process, and then the damage to stratospheric ozone would be much less than expected. On the other hand, when many chemical transformations occur in the atmosphere every second, it is quite likely that other mechanisms will be identified that directly or indirectly affect the formation and destruction of ozone. Finally, such models are able to identify and evaluate the significance of individual reactions or their groups in the formation of other gases that make up atmospheric air, as well as allow calculation of gas concentrations that are inaccessible to measurements.
And finally it was necessary to organize a wide network for measuring the content of various gases in the air, including nitrogen compounds, chlorine, etc., using ground stations, launching weather balloons and meteorological rockets, and aircraft flights for this purpose. Of course, the creation of a database was the most expensive task, which cannot be solved in a short time. However, only measurements could provide a starting point for theoretical research, being at the same time a touchstone of the truth of the hypotheses expressed.
Since the beginning of the 1970s, at least once every three years, special, constantly updated collections containing information on all significant atmospheric reactions, including photolysis reactions, have been published. Moreover, the error in determining the parameters of reactions between the gaseous components of air today is, as a rule, 10-20%.
The second half of this decade witnessed the rapid development of models describing chemical transformations in the atmosphere. Most of them were created in the USA, but they also appeared in Europe and the USSR. At first these were boxed (zero-dimensional), and then one-dimensional models. The former reproduced with varying degrees of reliability the content of the main atmospheric gases in a given volume - a box (hence their name) - as a result of chemical interactions between them. Since the conservation of the total mass of the air mixture was postulated, the removal of any of its fraction from the box, for example, by the wind, was not considered. Box models were convenient for elucidating the role of individual reactions or their groups in the processes of chemical formation and destruction of atmospheric gases, for assessing the sensitivity of the atmospheric gas composition to inaccuracies in determining reaction rates. With their help, the researchers could, by setting atmospheric parameters in the box (in particular, air temperature and density) corresponding to the altitude of aviation flights, estimate in a rough approximation how the concentrations of atmospheric impurities will change as a result of emissions of combustion products by aircraft engines. At the same time, box models were unsuitable for studying the problem of chlorofluorocarbons (CFCs), since they could not describe the process of their movement from the earth's surface into the stratosphere. This is where one-dimensional models came in handy, which combined taking into account a detailed description of chemical interactions in the atmosphere and the transport of impurities in the vertical direction. And although the vertical transfer was set rather roughly here, the use of one-dimensional models was a noticeable step forward, since they made it possible to somehow describe real phenomena.
Looking back, we can say that our modern knowledge are largely based on the rough work carried out in those years with the help of one-dimensional and box models. It made it possible to determine the mechanisms of formation of the gaseous composition of the atmosphere, to estimate the intensity of chemical sources and sinks of individual gases. An important feature of this stage in the development of atmospheric chemistry is that new ideas that were born were tested on models and widely discussed among specialists. The results obtained were often compared with the estimates of other scientific groups, since field measurements were clearly not enough, and their accuracy was very low. In addition, to confirm the correctness of modeling certain chemical interactions, it was necessary to carry out complex measurements, when the concentrations of all participating reagents would be determined simultaneously, which at that time, and even now, was practically impossible. (Until now, only a few measurements of the complex of gases from the Shuttle have been carried out over 2-5 days.) Therefore, model studies were ahead of experimental ones, and the theory did not so much explain the field observations as contributed to their optimal planning. For example, a compound such as chlorine nitrate ClONO2 first appeared in model studies and only then was discovered in the atmosphere. It was even difficult to compare the available measurements with model estimates, since the one-dimensional model could not take into account horizontal air movements, which is why the atmosphere was assumed to be horizontally homogeneous, and the obtained model results corresponded to some global mean state of it. However, in reality, the composition of the air over the industrial regions of Europe or the United States is very different from its composition over Australia or over the Pacific Ocean. Therefore, the results of any natural observation largely depend on the place and time of measurements and, of course, do not exactly correspond to the global average.
To eliminate this gap in modeling, in the 1980s, researchers created two-dimensional models that, along with vertical transport, also took into account air transport along the meridian (along the circle of latitude, the atmosphere was still considered homogeneous). The creation of such models at first was associated with significant difficulties.
First of all, the number of external model parameters increased sharply: at each grid node, it was necessary to set the vertical and interlatitudinal transport velocities, air temperature and density, and so on. Many parameters (first of all, the above-mentioned speeds) were not reliably determined in experiments and, therefore, were selected on the basis of qualitative considerations.
Secondly, the state of computer technology of that time significantly hindered the full development of two-dimensional models. Unlike economical one-dimensional and especially boxed models, two-dimensional models required significantly high costs computer memory and time. And as a result, their creators were forced to significantly simplify the schemes for accounting for chemical transformations in the atmosphere. Nevertheless, a complex of atmospheric studies, both model and full-scale using satellites, made it possible to draw a relatively harmonious, although far from complete, picture of the composition of the atmosphere, as well as to establish the main cause-and-effect relationships that cause changes in the content of individual air components. In particular, numerous studies have shown that aircraft flights in the troposphere do not cause any significant harm to tropospheric ozone, but their rise into the stratosphere seems to have negative consequences for the ozonosphere. The opinion of most experts on the role of CFCs was almost unanimous: the hypothesis of Rowland and Molin is confirmed, and these substances really contribute to the destruction of stratospheric ozone, and the regular increase in their industrial production is a time bomb, since the decay of CFCs does not occur immediately, but after tens and hundreds of years , so the effects of pollution will affect the atmosphere for a very long time. Moreover, if stored for a long time, chlorofluorocarbons can reach any, the most remote point of the atmosphere, and, therefore, this is a threat on a global scale. The time has come for coordinated political decisions.
In 1985, with the participation of 44 countries in Vienna, a convention for the protection of the ozone layer was developed and adopted, which stimulated its comprehensive study. However, the question of what to do with CFCs was still open. It was impossible to let the matter go by itself on the principle of “it will resolve itself”, but it is also impossible to ban the production of these substances overnight without huge damage to the economy. It would seem that there is a simple solution: you need to replace CFCs with other substances capable of performing the same functions (for example, in refrigeration units) and at the same time harmless or at least less dangerous for ozone. But implementing simple solutions is often very difficult. Not only did the creation of such substances and the establishment of their production require huge investments and time, criteria were needed to assess the impact of any of them on the atmosphere and climate.
Theorists are back in the spotlight. D. Webbles from the Livermore National Laboratory suggested using the ozone-depleting potential for this purpose, which showed how much the molecule of the substitute substance is stronger (or weaker) than the CFCl3 (freon-11) molecule affects atmospheric ozone. At that time, it was also well known that the temperature of the surface air layer significantly depends on the concentration of certain gaseous impurities (they were called greenhouse gases), primarily carbon dioxide CO2, water vapor H2O, ozone, etc. CFCs were also included in this category, and many their potential replacements. Measurements have shown that during the industrial revolution, the average annual global temperature of the surface air layer has grown and continues to grow, and this indicates significant and not always desirable changes in the Earth's climate. In order to bring this situation under control, along with the ozone-depleting potential of the substance, they also began to consider its global warming potential. This index indicated how much stronger or weaker the studied compound affects the air temperature than the same amount of carbon dioxide. The calculations performed showed that CFCs and alternatives had very high global warming potentials, but because their concentrations in the atmosphere were much lower than the concentrations of CO2, H2O or O3, their total contribution to global warming remained negligible. For the time being…
Tables of calculated values for the ozone depletion and global warming potentials of chlorofluorocarbons and their possible substitutes formed the basis of international decisions to reduce and subsequently ban the production and use of many CFCs (the Montreal Protocol of 1987 and its later additions). Perhaps the experts gathered in Montreal would not have been so unanimous (after all, the articles of the Protocol were based on the “thinkings” of theorists not confirmed by natural experiments), but another interested “person” spoke out for signing this document - the atmosphere itself.
The message about the discovery by British scientists at the end of 1985 of the "ozone hole" over Antarctica became, not without the participation of journalists, the sensation of the year, and the reaction of the world community to this message can be best described in one short word - shock. It is one thing when the threat of destruction of the ozone layer exists only in the long term, another thing when we are all faced with a fait accompli. Neither the townsfolk, nor politicians, nor specialists-theorists were ready for this.
It quickly became clear that none of the then existing models could reproduce such a significant reduction in ozone. This means that some important natural phenomena were either not taken into account or underestimated. Soon, field studies carried out as part of the program for studying the Antarctic phenomenon established that an important role in the formation of the “ozone hole”, along with the usual (gas-phase) atmospheric reactions, is played by the features of atmospheric air transport in the Antarctic stratosphere (its almost complete isolation from the rest of the atmosphere in winter), as well as at that time little studied heterogeneous reactions (reactions on the surface of atmospheric aerosols - dust particles, soot, ice floes, water drops, etc.). Only taking into account the above factors made it possible to achieve satisfactory agreement between the model results and observational data. And the lessons taught by the Antarctic “ozone hole” have seriously affected further development atmospheric chemistry.
First, a sharp impetus was given to a detailed study of heterogeneous processes proceeding according to laws different from those that determine gas-phase processes. Secondly, a clear realization has come that in a complex system, which is the atmosphere, the behavior of its elements depends on a whole complex of internal connections. In other words, the content of gases in the atmosphere is determined not only by the intensity of chemical processes, but also by air temperature, the transfer of air masses, and the characteristics of aerosol pollution. various parts atmosphere, etc. In turn, radiative heating and cooling, which form the temperature field of stratospheric air, depend on the concentration and spatial distribution of greenhouse gases, and, consequently, on atmospheric dynamic processes. Finally, non-uniform radiative heating of different belts of the globe and parts of the atmosphere generates atmospheric air movements and controls their intensity. Thus, not taking into account any feedback in the models can be fraught with large errors in the results obtained (although, we note in passing, and excessive complication of the model without urgent need is just as inappropriate as firing cannons at known representatives of birds).
If the relationship between air temperature and its gas composition was taken into account in two-dimensional models back in the 80s, then the use of three-dimensional models of the general circulation of the atmosphere to describe the distribution of atmospheric impurities became possible due to the computer boom only in the 90s. The first such general circulation models were used to describe the spatial distribution of chemically passive substances - tracers. Later, due to insufficient computer memory, chemical processes were set by only one parameter - the residence time of an impurity in the atmosphere, and only relatively recently, blocks of chemical transformations became full-fledged parts of three-dimensional models. Although the difficulties of representing atmospheric chemical processes in 3D in detail still remain, today they no longer seem insurmountable, and the best 3D models include hundreds of chemical reactions, along with the actual climatic transport of air in the global atmosphere.
At the same time, the widespread use of modern models does not at all cast doubt on the usefulness of the simpler ones mentioned above. It is well known that the more complex the model, the more difficult it is to separate the “signal” from the “model noise”, analyze the results obtained, identify the main cause-and-effect mechanisms, evaluate the impact of certain phenomena on the final result (and, therefore, the expediency of taking them into account in the model) . And here more simple models serve as an ideal testing ground, they allow you to get preliminary estimates that are further used in three-dimensional models, study new natural phenomena before they are included in more complex ones, etc.
Rapid scientific and technological progress has given rise to several other areas of research, one way or another related to atmospheric chemistry.
Satellite monitoring of the atmosphere. When regular replenishment of the database from satellites was established, for most of the most important components of the atmosphere, covering almost the entire globe, it became necessary to improve the methods of their processing. Here, there is data filtering (separation of the signal and measurement errors), and restoration of vertical profiles of impurity concentrations from their total contents in the atmospheric column, and data interpolation in those areas where direct measurements are impossible for technical reasons. In addition, satellite monitoring is complemented by airborne expeditions that are planned to solve various problems, for example, in the tropical Pacific Ocean, the North Atlantic, and even in the Arctic summer stratosphere.
Main part contemporary research- assimilation (assimilation) of these databases in models of varying complexity. In this case, the parameters are selected from the condition of the closest proximity of the measured and model values of the content of impurities at points (regions). Thus, the quality of the models is checked, as well as the extrapolation of the measured values beyond the regions and periods of measurements.
Estimation of concentrations of short-lived atmospheric impurities. Atmospheric radicals, which play a key role in atmospheric chemistry, such as hydroxyl OH, perhydroxyl HO2, nitric oxide NO, atomic oxygen in the excited state O (1D), etc., have the highest chemical reactivity and, therefore, very small (several seconds or minutes ) “lifetime” in the atmosphere. Therefore, the measurement of such radicals is extremely difficult, and the reconstruction of their content in the air is often carried out using model ratios of chemical sources and sinks of these radicals. For a long time, the intensities of sources and sinks were calculated from model data. With the advent of appropriate measurements, it became possible to reconstruct the concentrations of radicals on their basis, while improving models and expanding information about the gaseous composition of the atmosphere.
Reconstruction of the gas composition of the atmosphere in the pre-industrial period and earlier epochs of the Earth. Thanks to measurements in Antarctic and Greenland ice cores, whose age ranges from hundreds to hundreds of thousands of years, the concentrations of carbon dioxide, nitrous oxide, methane, carbon monoxide, as well as the temperature of those times, became known. Model reconstruction of the state of the atmosphere in those epochs and its comparison with the current one makes it possible to trace the evolution of the earth's atmosphere and assess the degree of human impact on the natural environment.
Assessment of the intensity of the sources of the most important air components. Systematic measurements of the content of gases in the surface air, such as methane, carbon monoxide, nitrogen oxides, became the basis for solving the inverse problem: estimating the amount of emissions into the atmosphere of gases from ground sources, according to their known concentrations. Unfortunately, only inventorying the perpetrators of the global turmoil - CFCs - is a relatively simple task, since almost all of these substances do not have natural sources and their total amount released into the atmosphere is limited by their production volume. The rest of the gases have heterogeneous and comparable power sources. For example, the source of methane is waterlogged areas, swamps, oil wells, coal mines; this compound is secreted by termite colonies and is even a waste product of cattle. Carbon monoxide enters the atmosphere as part of exhaust gases, as a result of fuel combustion, and also during the oxidation of methane and many organic compounds. It is difficult to directly measure emissions of these gases, but techniques have been developed to estimate the global sources of pollutant gases, the error of which has been significantly reduced in recent years, although it remains large.
Prediction of changes in the composition of the atmosphere and climate of the Earth Considering trends - trends in the content of atmospheric gases, estimates of their sources, growth rates of the Earth's population, the rate of increase in the production of all types of energy, etc. - special groups of experts create and constantly adjust scenarios for probable atmospheric pollution in the next 10, 30, 100 years. Based on them, with the help of models, possible changes in the gas composition, temperature and atmospheric circulation are predicted. Thus, it is possible to detect unfavorable trends in the state of the atmosphere in advance and try to eliminate them. The Antarctic shock of 1985 must not be repeated.
Phenomenon greenhouse effect atmosphere
In recent years, it has become clear that the analogy between an ordinary greenhouse and the greenhouse effect of the atmosphere is not entirely correct. At the end of the last century, the famous American physicist Wood, replacing ordinary glass with quartz in a laboratory model of a greenhouse and not finding any changes in the functioning of the greenhouse, showed that it was not a matter of delaying the thermal radiation of the soil by glass that transmits solar radiation, the role of glass in this case consists only in “cutting off” the turbulent heat exchange between the soil surface and the atmosphere.
The greenhouse (greenhouse) effect of the atmosphere is its property to let solar radiation through, but to delay terrestrial radiation, contributing to the accumulation of heat by the earth. Earth atmosphere relatively well transmits short-wave solar radiation, which is almost completely absorbed by the earth's surface. Heating up due to the absorption of solar radiation, the earth's surface becomes a source of terrestrial, mainly long-wave, radiation, some of which goes into outer space.
Effect of Increasing CO2 Concentration
Scientists - researchers continue to argue about the composition of the so-called greenhouse gases. Of greatest interest in this regard is the effect of increasing concentrations of carbon dioxide (CO2) on the greenhouse effect of the atmosphere. An opinion is expressed that the well-known scheme: “an increase in the concentration of carbon dioxide enhances the greenhouse effect, which leads to a warming of the global climate” is extremely simplified and very far from reality, since the most important “greenhouse gas” is not CO2 at all, but water vapor. At the same time, the reservation that the concentration of water vapor in the atmosphere is determined only by the parameters of the climate system itself is no longer tenable today, since the anthropogenic impact on the global water cycle has been convincingly proven.
As scientific hypotheses, we point out the following consequences of the coming greenhouse effect. First of all, According to the most common estimates, by the end of the 21st century, the content of atmospheric CO2 will double, which will inevitably lead to an increase in the average global surface temperature by 3–5 o C. At the same time, warming is expected in drier summers in the temperate latitudes of the Northern Hemisphere.
Secondly, it is assumed that such an increase in the average global surface temperature will lead to an increase in the level of the World Ocean by 20 - 165 centimeters due to the thermal expansion of water. As for the ice sheet of Antarctica, its destruction is not inevitable, since higher temperatures are needed for melting. In any case, the process of melting Antarctic ice will take a very long time.
Thirdly, Atmospheric CO2 concentrations can have a very beneficial effect on crop yields. The results of the experiments carried out allow us to assume that under the conditions of a progressive increase in the CO2 content in the air, natural and cultivated vegetation will reach optimal state; the leaf surface of plants will increase, the specific gravity of the dry matter of the leaves will increase, the average size fruits and the number of seeds, the ripening of cereals will accelerate, and their yield will increase.
Fourth, at high latitudes, natural forests, especially boreal forests, can be very sensitive to temperature changes. Warming can lead to a sharp reduction in the area of boreal forests, as well as to the movement of their border to the north, the forests of the tropics and subtropics will probably be more sensitive to changes in precipitation rather than temperature.
The light energy of the sun penetrates the atmosphere, is absorbed by the earth's surface and heats it. In this case, light energy is converted into thermal energy, which is released in the form of infrared or thermal radiation. This infrared radiation reflected from the surface of the earth is absorbed by carbon dioxide, while it heats up itself and heats the atmosphere. This means that the more carbon dioxide in the atmosphere, the more it captures the climate on the planet. The same thing happens in greenhouses, which is why this phenomenon is called the greenhouse effect.
If the so-called greenhouse gases continue to flow at the current rate, then in the next century the average temperature of the Earth will increase by 4 - 5 o C, which can lead to global warming of the planet.
Conclusion
Changing your attitude to nature does not mean at all that you should abandon technological progress. Stopping it will not solve the problem, but can only delay its solution. We must persistently and patiently strive to reduce emissions through the introduction of new environmental technologies to save raw materials, energy consumption and increase the number of planted plantings, educational activities of the ecological worldview among the population.
So, for example, in the USA, one of the enterprises for the production of synthetic rubber is located next to residential areas, and this does not cause protests from residents, because environmentally friendly technological schemes are operating, which in the past, with old technologies, were not clean.
This means that a strict selection of technologies that meet the most stringent criteria is needed, modern promising technologies will make it possible to achieve a high level of environmental friendliness in production in all industries and transport, as well as an increase in the number of planted green spaces in industrial zones and cities.
In recent years, experiment has taken the leading position in the development of atmospheric chemistry, and the place of theory is the same as in the classical, respectable sciences. But there are still areas where it is theoretical research that remains a priority: for example, only model experiments are able to predict changes in the composition of the atmosphere or evaluate the effectiveness of restrictive measures implemented under the Montreal Protocol. Starting from the solution of an important, but private problem, today atmospheric chemistry, in cooperation with related disciplines, covers the entire complex of problems in the study and protection of the environment. Perhaps we can say that the first years of the formation of atmospheric chemistry passed under the motto: “Do not be late!” The starting spurt is over, the run continues.
inanimate and Live nature, surrounding plants, animals and humans, is called the habitat (living environment, external environment). According to the definition of N.P. Naumov (1963), the environment is “everything that surrounds organisms and directly or indirectly affects their state, development, survival and reproduction.” From the habitat, organisms receive everything necessary for life and release the products of their metabolism into it.
Organisms can live in one or more living environments. For example, man, most birds, mammals, seed plants, lichens are inhabitants only of the terrestrial-air environment; most fish live only in the aquatic environment; dragonflies spend one phase in the water, and the other - in the air.
Aquatic life environment
The aquatic environment is characterized by a great originality of the physicochemical properties of organisms favorable for life. Among them: transparency, high thermal conductivity, high density (about 800 times the density of air) and viscosity, expansion upon freezing, the ability to dissolve many mineral and organic compounds, high mobility (fluidity), the absence of sharp temperature fluctuations (both daily and seasonal), the ability to equally easily support organisms that differ significantly in mass.
The unfavorable properties of the aquatic environment are: strong pressure drops, poor aeration (the oxygen content in the aquatic environment is at least 20 times lower than in the atmosphere), lack of light (especially little of it in the depths of water bodies), lack of nitrates and phosphates (necessary for the synthesis of living matter ).
Distinguish between fresh and sea water, which differ both in composition and in the amount of dissolved minerals. Sea water is rich in sodium, magnesium, chloride and sulfate ions, while fresh water is dominated by calcium and carbonate ions.
Organisms living in the aquatic environment of life constitute one biological group - hydrobionts.
In reservoirs, two ecologically special habitats (biotopes) are usually distinguished: the water column (pelagial) and the bottom (benthal). The organisms living there are called pelagos and benthos.
Among the pelagos, the following forms of organisms are distinguished: plankton - passively floating small representatives (phytoplankton and zooplankton); nekton - actively swimming large forms (fish, turtles, cephalopods); neuston - microscopic and small inhabitants of the surface film of water. In fresh water bodies (lakes, ponds, rivers, swamps, etc.), such ecological zoning is not very clearly expressed. The lower limit of life in the pelagial is determined by the depth of penetration of sunlight sufficient for photosynthesis and rarely reaches a depth of more than 2000 m.
In Bentali, special ecological zones of life are also distinguished: a zone of a gradual decrease in land (up to a depth of 200-2200 m); steep slope zone, oceanic bed (with an average depth of 2800-6000 m); depressions of the oceanic bed (up to 10,000 m); the edge of the coast, flooded with tides (littoral). The inhabitants of the littoral live in conditions of abundant solar lighting at low pressure, with frequent and significant temperature fluctuations. The inhabitants of the ocean floor zone, on the contrary, exist in complete darkness, at constantly low temperatures, oxygen deficiency and under enormous pressure, reaching almost a thousand atmospheres.
Ground-air environment of life
The land-air environment of life is the most complex in terms of ecological conditions and has a wide variety of habitats. This led to the greatest diversity of land organisms. The vast majority of animals in this environment move on a solid surface - soil, and plants take root on it. The organisms of this living environment are called aerobionts (terrabionts, from Latin terra - earth).
A characteristic feature of the environment under consideration is that the organisms living here significantly affect the living environment and in many respects create it themselves.
Favorable characteristics of this environment for organisms are the abundance of air with a high content of oxygen and sunlight. Unfavorable features include: sharp fluctuations in temperature, humidity and lighting (depending on the season, time of day and geographical location), constant moisture deficiency and its presence in the form of steam or drops, snow or ice, wind, change of seasons, relief features terrain, etc.
All organisms in the terrestrial-air environment of life are characterized by systems of economical use of water, various mechanisms of thermoregulation, high efficiency of oxidative processes, special organs for the assimilation of atmospheric oxygen, strong skeletal formations that allow the body to be maintained in conditions of low density of the environment, and various adaptations for protection against sudden temperature fluctuations. .
The ground-air environment in terms of its physical and chemical characteristics is considered to be quite severe in relation to all living things. But, despite this, life on land has reached a very high level, both in terms of the total mass of organic matter and in the diversity of forms of living matter.
The soil
The soil environment occupies an intermediate position between the water and ground-air environments. The temperature regime, low oxygen content, moisture saturation, the presence of a significant amount of salts and organic matter bring the soil closer to the aquatic environment. And sharp changes in the temperature regime, desiccation, saturation with air, including oxygen, bring the soil closer to the ground-air environment of life.
Soil is a loose surface layer of land, which is a mixture of mineral substances obtained from the decay of rocks under the influence of physical and chemical agents, and special organic substances resulting from the decomposition of plant and animal remains by biological agents. In the surface layers of the soil, where the freshest dead organic matter enters, many destructive organisms live - bacteria, fungi, worms, the smallest arthropods, etc. Their activity ensures the development of the soil from above, while the physical and chemical destruction of the bedrock contributes to the formation of soil from below.
As a living environment, the soil is distinguished by a number of features: high density, lack of light, reduced amplitude of temperature fluctuations, lack of oxygen, and a relatively high content of carbon dioxide. In addition, the soil is characterized by a loose (porous) structure of the substrate. The existing cavities are filled with a mixture of gases and aqueous solutions, which determines an extremely wide variety of conditions for the life of many organisms. On average, there are more than 100 billion cells of protozoa, millions of rotifers and tardigrades, tens of millions of nematodes, hundreds of thousands of arthropods, tens and hundreds of earthworms, mollusks and other invertebrates, hundreds of millions of bacteria, microscopic fungi (actinomycetes), algae and other microorganisms. The entire population of the soil - edaphobionts (edaphobius, from the Greek edaphos - soil, bios - life) interacts with each other, forming a kind of biocenotic complex, actively participating in the creation of the soil life environment itself and ensuring its fertility. Species inhabiting the soil environment of life are also called pedobionts (from the Greek paidos - a child, i.e., passing through the stage of larvae in their development).
The representatives of edaphobius in the process of evolution developed peculiar anatomical and morphological features. For example, animals have a valky body shape, small size, relatively strong integument, skin respiration, eye reduction, colorless integument, saprophagy (the ability to feed on the remains of other organisms). In addition, along with aerobicity, anaerobicity (the ability to exist in the absence of free oxygen) is widely represented.
The body as a living environment
As a living environment, the organism for its inhabitants is characterized by such positive features as: easily digestible food; constancy of temperature, salt and osmotic regimes; no risk of drying out; protection from enemies. Problems for the inhabitants of organisms are created by factors such as: lack of oxygen and light; limited living space; the need to overcome the protective reactions of the host; spread from one host to other hosts. In addition, this environment is always limited in time by the life of the host.
Sun skirt: types and how to wear it Black sun skirt with a T-shirt how to wear
Ground bird cherry Ground bird cherry cook
Own business: production of chips
How to care for your skin in spring Face masks in spring
Seizures in the corners of the mouth: causes and treatment in adults and children