Large cycle of substances in nature due to the interaction of solar energy with the deep energy of the Earth and redistributes matter between the biosphere and deeper horizons of the Earth.

Sedimentary rocks, formed due to the weathering of igneous rocks, in the mobile zones of the earth's crust again plunge into the zone of high temperatures and pressures. There they are melted down and form magma - the source of new igneous rocks. After the rise of these rocks to the earth's surface and the action of weathering processes, they are again transformed into new sedimentary rocks. The new cycle of circulation does not exactly repeat the old one, but introduces something new, which over time leads to very significant changes.

driving force great (geological) circulation are exogenous and endogenous geological processes.

Endogenous processes(processes of internal dynamics) occur under the influence of the internal energy of the Earth, released as a result of radioactive decay, chemical reactions of the formation of minerals, crystallization of rocks, etc. (for example, tectonic movements, earthquakes, magmatism, metamorphism).

Exogenous processes(processes external dynamics) flow under the influence of the external energy of the Sun. Examples: weathering of rocks and minerals, removal of destruction products from some areas of the earth's crust and their transfer to new areas, deposition and accumulation of destruction products with the formation of sedimentary rocks. To Ex.pr. relation geological activity of the atmosphere, hydrosphere, as well as living organisms and humans.

The largest landforms (continents and oceanic depressions) and large landforms (mountains and plains) were formed due to endogenous processes, while medium and small landforms (river valleys, hills, ravines, dunes, etc.), superimposed on larger landforms, were formed due to account of exogenous processes. Thus, endogenous and exogenous processes are opposite. The former lead to the formation of large landforms, the latter to their smoothing.

Examples of the geological cycle. Igneous rocks are transformed into sedimentary rocks as a result of weathering. In the mobile zones of the earth's crust, they sink into the depths of the Earth. There, under the influence of high temperatures and pressures, they melt and form magma, which, rising to the surface and, solidifying, forms igneous rocks.

An example of a large cycle is the circulation of water between land and ocean through the atmosphere (Fig. 2.1).

Rice. 2.1. The generally accepted scheme of hydrological (climatic)

water cycle in nature

Moisture evaporated from the surface of the World Ocean (which consumes almost half of the solar energy coming to the Earth's surface) is transferred to land, where it falls in the form of precipitation, which again returns to the ocean in the form of surface and underground runoff. The water cycle also occurs according to a simpler scheme: evaporation of moisture from the surface of the ocean - condensation of water vapor - precipitation on the same water surface of the ocean.

The water cycle as a whole plays a major role in shaping natural conditions on our planet. Taking into account the transpiration of water by plants and its absorption in the biogeochemical cycle, the entire supply of water on Earth decays and is restored in 2 million years.

Thus, the geological circulation of substances proceeds without the participation of living organisms and redistributes matter between the biosphere and the deeper layers of the Earth.

Large (geological) and small (biogeochemical) cycles of matter

All substances on our planet are in the process of circulation. Solar energy causes two cycles of matter on Earth:

Large (geological or abiotic);

Small (biotic, biogenic or biological).

The cycles of matter and the flows of cosmic energy create the stability of the biosphere. The cycle of solid matter and water that occurs as a result of the action abiotic factors(inanimate nature), is called a large geological cycle. With a large geological cycle (millions of years flow), rocks are destroyed, weathered, substances dissolve and enter the World Ocean; geotectonic changes are taking place, the sinking of the continents, the rise of the seabed. The water cycle time in glaciers is 8,000 years, in rivers - 11 days. It is the large circulation that supplies living organisms with nutrients and largely determines the conditions for their existence.

A large, geological cycle in the biosphere is characterized by two important points: oxygen carbon geological

• a) is carried out throughout the entire geological development of the Earth;
• b) is a modern planetary process that takes a leading part in the further development of the biosphere.

At the present stage of human development, as a result of a large circulation, pollutants are also transported over long distances - oxides of sulfur and nitrogen, dust, radioactive impurities. The territories of temperate latitudes of the Northern Hemisphere were subjected to the greatest pollution.

A small, biogenic or biological circulation of substances occurs in solid, liquid and gaseous phases with the participation of living organisms. The biological cycle, in contrast to the geological cycle, requires less energy. The small cycle is part of a large one, occurs at the level of biogeocenoses (within ecosystems) and lies in the fact that nutrients soils, water, carbon are accumulated in the substance of plants, spent on building the body. The decay products of organic matter decompose to mineral components. The small cycle is not closed, which is associated with the entry of substances and energy into the ecosystem from the outside and with the release of some of them into the biospheric cycle.

Many are involved in the large and small cycles. chemical elements and their compounds, but the most important of them are those that determine the current stage of development of the biosphere, associated with human economic activity. These include the cycles of carbon, sulfur and nitrogen (their oxides are the main pollutants of the atmosphere), as well as phosphorus (phosphates are the main pollutant of continental waters). Almost all pollutants act as harmful, and they are classified as xenobiotics. Currently, the cycles of xenobiotics - toxic elements - mercury (a food contaminant) and lead (a component of gasoline) are of great importance. In addition, many substances of anthropogenic origin (DDT, pesticides, radionuclides, etc.) enter the small circulation from the large circulation, which cause harm to biota and human health.

The essence of the biological cycle is the flow of two opposite, but interrelated processes - the creation of organic matter and its destruction by living matter.

In contrast to the large cycle, the small one has a different duration: seasonal, annual, perennial and secular small cycles are distinguished. Circulation chemical substances from the inorganic environment through vegetation and animals back to the inorganic environment using solar energy chemical reactions is called the biogeochemical cycle.

The present and future of our planet depends on the participation of living organisms in the functioning of the biosphere. In the circulation of substances, living matter, or biomass, performs biogeochemical functions: gas, concentration, redox and biochemical.

The biological cycle occurs with the participation of living organisms and consists in the reproduction of organic matter from inorganic and the decomposition of this organic to inorganic through the food trophic chain. The intensity of production and destruction processes in the biological cycle depends on the amount of heat and moisture. For example, the low rate of decomposition of organic matter in the polar regions depends on the deficit of heat.

An important indicator of the intensity of the biological cycle is the rate of circulation of chemical elements. The intensity is characterized by an index equal to the ratio of the mass of forest litter to the litter. The higher the index, the lower the intensity of the cycle.

Index in coniferous forests- 10 - 17; broad-leaved 3 - 4; savanna no more than 0.2; humid tropical forests no more than 0.1, i.e. here the biological cycle is the most intense.

The flow of elements (nitrogen, phosphorus, sulfur) through microorganisms is an order of magnitude higher than through plants and animals. The biological cycle is not completely reversible, it is closely related to the biogeochemical cycle. Chemical elements circulate in the biosphere along various paths of the biological cycle:

• - absorbed by living matter and charged with energy;
• - leave living matter, releasing energy into the external environment.

These cycles are of two types: the circulation of gaseous substances; sedimentary cycle (reserve in the earth's crust).

The cycles themselves consist of two parts:

• - reserve fund (this is a part of the substance that is not associated with living organisms);
• - mobile (exchange) fund (a smaller part of the substance associated with direct exchange between organisms and their immediate environment).

Cycles are divided into:

• - cycles gas type with a reserve fund in the earth's crust (cycles of carbon, oxygen, nitrogen) - capable of rapid self-regulation;
• - sedimentary cycles with a reserve fund in the earth's crust (circulations of phosphorus, calcium, iron, etc.) - are more inert, the bulk of the substance is in a form "inaccessible" to living organisms.

Cycles can also be divided into:

• - closed (circulation of gaseous substances, for example, oxygen, carbon and nitrogen - a reserve in the atmosphere and hydrosphere of the ocean, so the shortage is quickly compensated);
• - open (creating a reserve fund in the earth's crust, for example, phosphorus - therefore, losses are poorly compensated, i.e. a deficit is created).

The energy basis for the existence of biological cycles on Earth and their initial link is the process of photosynthesis. Each new cycle of circulation is not an exact repetition of the previous one. For example, during the evolution of the biosphere, some of the processes were irreversible, resulting in the formation and accumulation of biogenic precipitation, an increase in the amount of oxygen in the atmosphere, a change in the quantitative ratios of isotopes of a number of elements, etc.

The circulation of substances is commonly called biogeochemical cycles. The main biogeochemical (biospheric) cycles of substances: the water cycle, the oxygen cycle, the nitrogen cycle (participation of nitrogen-fixing bacteria), the carbon cycle (participation of aerobic bacteria; annually about 130 tons of carbon is discharged into the geological cycle), the phosphorus cycle (participation of soil bacteria; annually in 14 million tons of phosphorus are washed out of the oceans), the sulfur cycle, the cycle of metal cations.

The water cycle

The water cycle is a closed cycle that can be performed, as mentioned above, even in the absence of life, but living organisms modify it.

The cycle is based on the principle that total evaporation is compensated by precipitation. For the planet as a whole, evaporation and precipitation balance each other out. At the same time, more water evaporates from the ocean than returns with precipitation. On land, on the contrary, more precipitation falls, but the excess flows into lakes and rivers, and from there again into the ocean. The balance of moisture between continents and oceans is maintained by river runoff.

Thus, the global hydrological cycle has four main flows: precipitation, evaporation, moisture transfer, and transpiration.

Water - the most common substance in the biosphere - serves not only as a habitat for many organisms, but also is integral part bodies of all living beings. Despite the enormous importance of water in all life processes occurring in the biosphere, living matter does not play a decisive role in the large water cycle on the globe. The driving force of this cycle is the energy of the sun, which is spent on the evaporation of water from the surface of water basins or land. Evaporated moisture condenses in the atmosphere in the form of wind-blown clouds; As clouds cool, precipitation falls.

The total amount of free unbound water (the proportion of oceans and seas where liquid salt water) accounts for 86 to 98%. The rest of the water ( fresh water) is stored in polar caps and glaciers and forms water basins and its groundwater. Precipitation that falls on the surface of land covered with vegetation is partially retained by the leaf surface and subsequently evaporates into the atmosphere. Moisture reaching the soil can join surface runoff or be absorbed by the soil. Completely absorbed by the soil (this depends on the type of soil, features of rocks and vegetation cover), excess sediment can seep deep into the groundwater. If the amount of precipitation exceeds the moisture capacity of the upper layers of the soil, surface runoff begins, the speed of which depends on the condition of the soil, the steepness of the slope, the duration of precipitation and the nature of the vegetation (vegetation can protect the soil from water erosion). Water trapped in the soil can evaporate from its surface or, after absorption by plant roots, be transpired (evaporate) into the atmosphere through the leaves.

The transpiration flow of water (soil - plant roots - leaves - atmosphere) is the main path of water through living matter in its large circulation on our planet.

The carbon cycle

The whole variety of organic substances, biochemical processes and life forms on Earth depends on the properties and characteristics of carbon. The carbon content in most living organisms is about 45% of their dry biomass. All the living matter of the planet is involved in the cycle of organic matter and all carbon of the Earth, which continuously arises, mutates, dies, decomposes, and in this sequence carbon is transferred from one organic substance to the construction of another along the food chain. In addition, all living things breathe, releasing carbon dioxide.

The carbon cycle on land. The carbon cycle is maintained through photosynthesis ground plants and oceanic phytoplankton. By absorbing carbon dioxide (fixing inorganic carbon), plants use energy to sunlight convert it into organic compounds - creating their own biomass. At night, plants, like all living things, breathe, releasing carbon dioxide.

Dead plants, corpses and excrement of animals serve as food for numerous heterotrophic organisms (animals, saprophyte plants, fungi, microorganisms). All these organisms live mainly in the soil and in the process of life create their own biomass, which includes organic carbon. They also release carbon dioxide, creating "soil respiration". Often, dead organic matter is not completely decomposed and humus (humus) accumulates in soils, which plays an important role in soil fertility. The degree of mineralization and humification of organic substances depends on many factors: humidity, temperature, physical properties of the soil, composition of organic residues, etc. Under the action of bacteria and fungi, humus can decompose to carbon dioxide and mineral compounds.

The carbon cycle in the oceans. The carbon cycle in the ocean is different from that on land. In the ocean, the weak link of organisms of higher trophic levels, and therefore all links of the carbon cycle. The transit time of carbon through the trophic link of the ocean is short, and the amount of carbon dioxide released is insignificant.

The ocean plays the role of the main regulator of carbon dioxide content in the atmosphere. There is an intensive exchange of carbon dioxide between the ocean and the atmosphere. Ocean waters have a large dissolving power and buffer capacity. The system consisting of carbonic acid and its salts (carbonates) is a kind of depot of carbon dioxide, connected with the atmosphere through the diffusion of CO? from water to atmosphere and vice versa.

Phytoplankton photosynthesis proceeds intensively in the ocean during the day, while free carbon dioxide is intensively consumed, carbonates serve as an additional source of its formation. At night, with an increase in the content of free acid due to the respiration of animals and plants, a significant part of it again enters into the composition of carbonates. The ongoing processes go in the following directions: living matter? CO?? H?CO?? Sa(NSO?)?? CaCO?.

In nature, a certain amount of organic matter does not undergo mineralization as a result of lack of oxygen, high acidity of the environment, specific burial conditions, etc. Part of the carbon leaves the biological cycle in the form of inorganic (limestone, chalk, corals) and organic (shale, oil, coal) deposits.

Human activity is making significant changes to the carbon cycle on our planet. Landscapes, types of vegetation, biocenoses and their food chains are changing, vast areas of the land surface are being drained or irrigated, soil fertility is improving (or worsening), fertilizers and pesticides are being applied, etc. The most dangerous is the release of carbon dioxide into the atmosphere as a result of fuel combustion. This increases the rate of carbon cycle and shortens its cycle.

Oxygen cycle

Oxygen is prerequisite the existence of life on Earth. It is included in almost all biological compounds, participates in bio chemical reactions oxidation of organic substances that provide energy for all life processes of organisms in the biosphere. Oxygen ensures the respiration of animals, plants and microorganisms in the atmosphere, soil, water, participates in chemical oxidation reactions occurring in rocks, soils, silts, aquifers.

The main branches of the oxygen cycle:

• - the formation of free oxygen during photosynthesis and its absorption during the respiration of living organisms (plants, animals, microorganisms in the atmosphere, soil, water);
• - formation of an ozone screen;
• - creation of redox zoning;
• - oxidation of carbon monoxide during volcanic eruptions, accumulation of sulfate sedimentary rocks, oxygen consumption in human activities, etc.; everywhere molecular oxygen is involved in photosynthesis.

nitrogen cycle

Nitrogen is a part of biologically important organic substances of all living organisms: proteins, nucleic acids, lipoproteins, enzymes, chlorophyll, etc. Despite the content of nitrogen (79%) in the air, it is deficient for living organisms.

Nitrogen in the biosphere is in a gaseous form (N2) inaccessible to organisms - it is chemically low active, therefore it cannot be directly used by higher plants (and most lower plants) and the animal world. Plants absorb nitrogen from the soil in the form of ammonium ions or nitrate ions, i.e. so-called fixed nitrogen.

There are atmospheric, industrial and biological nitrogen fixation.

Atmospheric fixation occurs when the atmosphere is ionized by cosmic rays and at strong electrical discharges during thunderstorms, nitrogen and ammonia oxides are formed from the molecular nitrogen of the air, which, due to atmospheric precipitation, turn into ammonium, nitrite, nitrate nitrogen and enter the soil and water basins.

Industrial fixation occurs as a result economic activity person. The atmosphere is polluted with nitrogen compounds by plants producing nitrogen compounds. Hot emissions from thermal power plants, factories, spacecraft, supersonic aircraft oxidize nitrogen in the air. Nitrogen oxides, interacting with air water vapor with precipitation, return to the ground, enter the soil in ionic form.

Biological fixation plays a major role in the nitrogen cycle. It is carried out by soil bacteria:

• - nitrogen-fixing bacteria (and blue-green algae);
• - microorganisms living in symbiosis with higher plants (nodule bacteria);
• - ammonifying;
• - nitrifying;
• - denitrifying.

Freely living in the soil, nitrogen-fixing aerobic (existing in the presence of oxygen) bacteria (Azotobacter) are able to fix atmospheric molecular nitrogen due to the energy obtained from the oxidation of soil organic matter during respiration, ultimately binding it with hydrogen and introducing it in the form of an amino group (- NH2) into the composition of amino acids in your body. Molecular nitrogen is also capable of fixing some anaerobic (living in the absence of oxygen) bacteria that exist in the soil (Clostridium). Dying off, both those and other microorganisms enrich the soil with organic nitrogen.

Blue-green algae, which are especially important for the soils of rice fields, are also capable of biological fixation of molecular nitrogen.

The most effective biological fixation of atmospheric nitrogen occurs in bacteria living in symbiosis in the nodules of leguminous plants (nodule bacteria).

These bacteria (Rizobium) use the energy of the host plant to fix nitrogen while supplying the host's terrestrial organs with available nitrogen compounds.

Assimilated nitrogen compounds from the soil in nitrate and ammonium forms, plants build the necessary nitrogen-containing compounds of their body (nitrate nitrogen in plant cells is preliminarily restored). Producer plants supply nitrogenous substances to the entire animal world and humanity. Dead plants are used, according to the trophic chain, by bioreducers.

Ammonifying microorganisms decompose organic substances containing nitrogen (amino acids, urea) with the formation of ammonia. Part of the organic nitrogen in the soil is not mineralized, but is converted into humic substances, bitumen, and components of sedimentary rocks.

Ammonia (as the ammonium ion) can enter the root system plants, or used in nitrification processes.

Nitrifying microorganisms are chemosynthetics, they use the energy of ammonia oxidation to nitrates and nitrites to nitrates to ensure all life processes. Due to this energy, nitrifiers restore carbon dioxide and build the organic substances of their body. Oxidation of ammonia during nitrification proceeds according to the following reactions:

NH? + 3O? ? 2HNO? + 2H?O + 600 kJ (148 kcal).

HNO? +O? ? 2HNO? + 198 kJ (48 kcal).

Nitrates formed in the processes of nitrification again enter the biological cycle, are absorbed from the soil by the roots of plants or after entering with water runoff into water basins - phytoplankton and phytobenthos.

Along with organisms that fix atmospheric nitrogen and nitrify it, there are microorganisms in the biosphere that can reduce nitrates or nitrites to molecular nitrogen. Such microorganisms, called denitrifiers, with a lack of free oxygen in water or soil, use the oxygen of nitrates to oxidize organic substances:

C?H??O?(glucose) + 24KNO? ? 24KHCO? + 6CO? + 12N? + 18H?O + energy

The energy released at the same time serves as the basis for all vital activity of denitrifying microorganisms.

Thus, living substances play an exceptional role in all links of the cycle.

At present, the industrial fixation of atmospheric nitrogen by humans plays an increasingly important role in the nitrogen balance of soils and, consequently, in the entire nitrogen cycle in the biosphere.

Phosphorus cycle

The phosphorus cycle is simpler. While the reservoir of nitrogen is air, the reservoir of phosphorus is rocks, from which it is released during erosion.

Carbon, oxygen, hydrogen and nitrogen migrate more easily and faster in the atmosphere, as they are in gaseous form, forming gaseous compounds in biological cycles. For all other elements, except for sulfur, necessary for the existence of living matter, the formation of gaseous compounds in biological cycles is uncharacteristic. These elements migrate mainly in the form of ions and molecules dissolved in water.

Phosphorus, assimilated by plants in the form of orthophosphoric acid ions, plays an important role in the life of all living organisms. It is part of ADP, ATP, DNA, RNA, and other compounds.

The cycle of phosphorus in the biosphere is open. In terrestrial biogeocenoses, phosphorus, after absorption by plants from the soil through the food chain, again enters the soil in the form of phosphates. The main amount of phosphorus is again absorbed by the root system of plants. Partially, phosphorus can be washed out with the runoff of rainwater from the soil into water basins.

In natural biogeocenoses, there is often a lack of phosphorus, and in an alkaline and oxidized environment, it is usually found in the form of insoluble compounds.

A large amount of phosphates contain rocks of the lithosphere. Some of them gradually pass into the soil, some are developed by man for the production of phosphate fertilizers, most of them are leached and washed into the hydrosphere. There they are used by phytoplankton and related organisms at different trophic levels of complex food chains.

In the World Ocean, the loss of phosphates from the biological cycle occurs due to the deposition of plant and animal remains at great depths. Since phosphorus moves mainly from the lithosphere to the hydrosphere with water, it migrates to the lithosphere biologically (eating fish by seabirds, using benthic algae and fishmeal as fertilizer, etc.).

Of all the elements of the mineral nutrition of plants, phosphorus can be considered deficient.

Sulfur cycle

For living organisms, sulfur is of great importance, since it is part of the sulfur-containing amino acids (cystine, cysteine, methionine, etc.). Being in the composition of proteins, sulfur-containing amino acids maintain the necessary three-dimensional structure of protein molecules.

Sulfur is absorbed by plants from the soil only in the oxidized form, in the form of an ion. In plants, sulfur is reduced and is part of amino acids in the form of sulfhydryl (-SH) and disulfide (-S-S-) groups.

Animals assimilate only reduced sulfur, which is part of organic matter. After the death of plant and animal organisms, sulfur returns to the soil, where, as a result of the activity of numerous forms of microorganisms, it undergoes transformations.

Under aerobic conditions, some microorganisms oxidize organic sulfur to sulfates. Sulfate ions, being absorbed by the roots of plants, are again included in the biological cycle. Some sulfates can be included in water migration and removed from the soil. In soils rich in humic substances, a significant amount of sulfur is found in organic compounds, which prevents its leaching.

Under anaerobic conditions, the decomposition of organic sulfur compounds produces hydrogen sulfide. If sulfates and organic substances are in an oxygen-free environment, then the activity of sulfate-reducing bacteria is activated. They use the oxygen of sulfates to oxidize organic matter and thus obtain the energy necessary for their existence.

Sulfate-reducing bacteria are common in groundwater, silt and stagnant sea water. Hydrogen sulfide is a poison for most living organisms, so its accumulation in water-filled soil, lakes, estuaries, etc. significantly reduces or even completely stops vital processes. Such a phenomenon is observed in the Black Sea at a depth below 200 m from its surface.

Thus, to create a favorable environment, it is necessary to oxidize hydrogen sulfide to sulfate ions, which will destroy the harmful effect of hydrogen sulfide, sulfur will turn into a form accessible to plants - in the form of sulfate salts. This role is performed in nature by a special group of sulfur bacteria (colorless, green, purple) and thionic bacteria.

Colorless sulfur bacteria are chemosynthetic: they use the energy obtained from the oxidation of hydrogen sulfide by oxygen to elemental sulfur and its further oxidation to sulfates.

Colored sulfur bacteria are photosynthetic organisms that use hydrogen sulfide as a hydrogen donor to reduce carbon dioxide.

The resulting elemental sulfur in green sulfur bacteria is released from the cells, in purple bacteria it accumulates inside the cells.

The overall reaction of this process is photoreduction:

CO?+ 2H?S light? (CH?O) + H?O +2S.

Thion bacteria oxidize elemental sulfur and its various reduced compounds to sulfates at the expense of free oxygen, returning it back to the mainstream of the biological cycle.

In the processes of the biological cycle, where sulfur is converted, living organisms, especially microorganisms, play a huge role.

The main reservoir of sulfur on our planet is the World Ocean, since sulfate ions continuously enter it from the soil. Part of the sulfur from the ocean returns to land through the atmosphere according to the scheme hydrogen sulfide - oxidizing it to sulfur dioxide - dissolving the latter in rainwater with the formation of sulfuric acid and sulfates - returning sulfur with precipitation to the Earth's soil cover.

Cycle of inorganic cations

In addition to the basic elements that make up living organisms (carbon, oxygen, hydrogen, phosphorus and sulfur), many other macro- and microelements - inorganic cations - are vital. In water basins, plants obtain the metal cations they need directly from environment. On land, the main source of inorganic cations is the soil, which received them in the process of destruction of parent rocks. In plants, the cations absorbed by the root systems move to the leaves and other organs; some of them (magnesium, iron, copper and a number of others) are part of biologically important molecules (chlorophyll, enzymes); others, staying in free form, are involved in maintaining the necessary colloidal properties of cell protoplasm and perform various other functions.

When living organisms die, inorganic cations return to the soil in the process of mineralization of organic substances. The loss of these components from the soil occurs as a result of leaching and removal of metal cations with rainwater, rejection and removal of organic matter by humans during the cultivation of agricultural plants, logging, mowing grass for livestock feed, etc.

Rational application mineral fertilizers, soil reclamation, application of organic fertilizers, proper agricultural technology will help restore and maintain the balance of inorganic cations in the biocenoses of the biosphere.

Anthropogenic cycling: cycling of xenobiotics (mercury, lead, chromium)

Humanity is part of nature and can only exist in constant interaction with it.

There are similarities and contradictions between the natural and anthropogenic circulation of matter and energy occurring in the biosphere.

The natural (biogeochemical) cycle of life has the following features:

• - the use of solar energy as a source of life and all its manifestations based on thermodynamic laws;
• - it is carried out without waste, i.e. all the products of its vital activity are mineralized and re-included in the next cycle of the circulation of substances. At the same time, spent, devalued thermal energy. During the biogeochemical cycle of substances, waste is generated, i.e. reserves in the form of coal, oil, gas and other mineral resources. In contrast to the waste-free natural cycle, the anthropogenic cycle is accompanied by an increase in waste every year.

There is nothing useless or harmful in nature, even volcanic eruptions have benefits, because the necessary elements (for example, nitrogen) enter the air with volcanic gases.

There is a law of global closure of the biogeochemical circulation in the biosphere, which is valid at all stages of its development, as well as a rule for increasing the closure of the biogeochemical circulation in the course of succession.

Humans play a huge role in the biogeochemical cycle, but in the opposite direction. Man violates the existing cycles of substances, and this manifests his geological force - destructive in relation to the biosphere. As a result of anthropogenic activity, the degree of isolation of biogeochemical cycles decreases.

The anthropogenic cycle is not limited to the energy of sunlight captured by the green plants of the planet. Mankind uses the energy of fuel, hydro and nuclear power plants.

It can be argued that anthropogenic activity at the present stage is a huge destructive force for the biosphere.

The biosphere has a special property - significant resistance to pollutants. This stability is based on the natural ability of the various components natural environment to self-purification and self-healing. But not limitless. The possible global crisis caused the need to build a mathematical model of the biosphere as a whole (the "Gaia" system) in order to obtain information about the possible state of the biosphere.

A xenobiotic is a substance alien to living organisms that appears as a result of anthropogenic activities (pesticides, preparations household chemicals and other pollutants) that can cause disruption of biotic processes, incl. illness or death. Such pollutants do not undergo biodegradation, but accumulate in trophic chains.

Mercury is a very rare element. It is dispersed in the earth's crust and only in a few minerals, such as cinnabar, is contained in a concentrated form. Mercury is involved in the cycle of matter in the biosphere, migrating in the gaseous state and in aqueous solutions.

It enters the atmosphere from the hydrosphere during evaporation, during release from cinnabar, with volcanic gases and gases from thermal springs. Part of the gaseous mercury in the atmosphere passes into the solid phase and is removed from the air. Fallen mercury is absorbed by soils, especially clay, water and rocks. In combustible minerals - oil and coal - mercury contains up to 1 mg / kg. There are approximately 1.6 billion tons in the water mass of the oceans, 500 billion tons in bottom sediments, and 2 million tons in plankton. About 40 thousand tons are carried out by river waters from land every year, which is 10 times less than what enters the atmosphere during evaporation (400 thousand tons). About 100 thousand tons fall on the land surface annually.

Mercury from natural component the natural environment has become one of the most hazardous man-made emissions into the biosphere for human health. It is widely used in metallurgy, chemical, electrical, electronic, pulp and paper and pharmaceutical industries and is used for the production of explosives, varnishes and paints, as well as in medicine. Industrial effluents and atmospheric emissions, along with mercury mines, mercury production plants and thermal power plants (CHP and boiler houses) using coal, oil and oil products, are the main sources of biosphere pollution with this toxic component. In addition, mercury is an ingredient in organomercury pesticides used in agriculture to treat seeds and protect crops from pests. It enters the human body with food (eggs, pickled grain, meat of animals and birds, milk, fish).

Mercury in water and bottom sediments of rivers

It has been established that about 80% of mercury entering natural water bodies is in a dissolved form, which ultimately contributes to its spread over long distances along with water flows. The pure element is non-toxic.

Mercury is found in bottom silt water more often in relatively harmless concentrations. Inorganic mercury compounds are converted into toxic organic mercury compounds, such as methylmercury CH?Hg and ethylmercury C?H?Hg, by bacteria living in detritus and sediment, in the bottom silt of lakes and rivers, in the mucus that covers the bodies of fish, and also in fish stomach mucus. These compounds are easily soluble, mobile and highly toxic. The chemical basis of the aggressive action of mercury is its affinity for sulfur, in particular with the hydrogen sulfide group in proteins. These molecules bind to chromosomes and brain cells. Fish and shellfish can accumulate them to dangerous levels for the person who eats them, causing Minamata disease.

Metal mercury and its inorganic compounds act mainly on the liver, kidneys and intestinal tract, however, under normal conditions, they are relatively quickly excreted from the body and the amount dangerous for the human body does not have time to accumulate. Methylmercury and other alkyl mercury compounds are much more dangerous, because cumulation occurs - the toxin enters the body faster than it is excreted from the body, acting on the central nervous system.

Bottom sediments are an important characteristic of aquatic ecosystems. By accumulating heavy metals, radionuclides and highly toxic organic substances, bottom sediments, on the one hand, contribute to the self-purification of aquatic environments, and on the other hand, they are permanent source secondary pollution of water bodies. Bottom sediments are a promising object of analysis, reflecting a long-term pattern of pollution (especially in slow-flowing water bodies). Moreover, the accumulation of inorganic mercury in bottom sediments is observed especially in river mouths. A tense situation may arise when the adsorption capacity of sediments (silt, precipitation) is exhausted. When the adsorption capacity is reached, heavy metals, incl. mercury will enter the water.

It is known that under marine anaerobic conditions in the sediments of dead algae, mercury attaches hydrogen and passes into volatile compounds.

With the participation of microorganisms, metallic mercury can be methylated in two stages:

CH?Hg+ ? (CH?)?Hg

Methylmercury appears in the environment practically only during the methylation of inorganic mercury.

The biological half-life of mercury is long, it is 70-80 days for most tissues of the human body.

Mercury contamination is known to occur early in the food chain big fish e.g. swordfish, tuna. At the same time, it is not without interest to note that, to an even greater extent than in fish, mercury accumulates (accumulates) in oysters.

Mercury enters the human body through breathing, with food and through the skin according to the following scheme:

First, there is a transformation of mercury. This element occurs naturally in several forms.

Metallic mercury, used in thermometers, and its inorganic salts (eg chloride) are eliminated from the body relatively quickly.

Much more toxic are alkyl mercury compounds, in particular methyl and ethyl mercury. These compounds are very slowly excreted from the body - only about 1% of the total amount per day. Although most of the mercury that enters natural waters, is contained there in the form of inorganic compounds, in fish it always turns out to be in the form of much poisonous methylmercury. Bacteria in the bottom silt of lakes and rivers, in the mucus that covers the bodies of fish, as well as in the mucus of the fish stomach, are able to convert inorganic mercury compounds into methylmercury.

Second, selective accumulation, or biological accumulation (concentration), raises the mercury content in fish and shellfish to levels many times higher than in bay water. Fish and shellfish that live in the river accumulate methylmercury to concentrations that are dangerous for humans who use them for food.

% of the world's fish catch contains mercury in an amount not exceeding 0.5 mg/kg, and 95% - below 0.3 mg/kg. Almost all mercury in fish is in the form of methylmercury.

Given the different toxicity of mercury compounds for humans in food products, it is necessary to determine inorganic (total) and organically bound mercury. We only determine the total mercury content. According to medical and biological requirements, the content of mercury in freshwater predatory fish is allowed 0.6 mg/kg, in marine fish - 0.4 mg/kg, in freshwater non-predatory fish only 0.3 mg/kg, and in tuna up to 0.7 mg/kg. kg. In products baby food the content of mercury should not exceed 0.02 mg/kg in canned meat, 0.15 mg/kg in canned fish, in the rest - 0.01 mg/kg.

Lead is present in almost all components of the natural environment. It contains 0.0016% in the earth's crust. The natural level of lead in the atmosphere is 0.0005 mg/m3. Most of it is deposited with dust, about 40% falls with atmospheric precipitation. Plants get lead from soil, water and atmospheric fallout, while animals get lead from plants and water. Metal enters the human body with food, water and dust.

The main sources of lead pollution of the biosphere are gasoline engines, the exhaust gases of which contain triethyl lead, thermal power plants that burn coal, mining, metallurgical and chemical industries. A significant amount of lead is introduced into the soil along with wastewater used as fertilizer. To extinguish a burning reactor Chernobyl nuclear power plant lead was also used, which entered the air pool and dispersed over vast areas. With an increase in environmental pollution with lead, its deposition in the bones, hair, and liver increases.

Chromium. The most dangerous is toxic chromium (6+), which is mobilized in acidic and alkaline soils, in fresh and marine waters. AT sea ​​water chromium is 10 - 20% represented by the Cr (3+) form, 25 - 40% - by Cr (6+), 45 - 65% - by the organic form. In the pH range 5 - 7, Cr (3+) predominates, and at pH > 7 - Cr (6+). It is known that Cr (6+) and organic chromium compounds do not co-precipitate with iron hydroxide in sea water.

Natural cycles of substances are practically closed. In natural ecosystems, matter and energy are spent sparingly, and the waste of some organisms is an important condition for the existence of others. The anthropogenic cycle of substances is accompanied by a huge consumption of natural resources and a large amount of waste that causes environmental pollution. Creating even the most perfect treatment facilities does not solve the problem, so it is necessary to develop low-waste and waste-free technologies that make it possible to make the anthropogenic cycle as closed as possible. Theoretically, it is possible to create a waste-free technology, but low-waste technologies are real.

Adaptation to natural phenomena

Adaptations are various adaptations to the environment developed by organisms (from the simplest to the highest) in the process of evolution. The ability to adapt is one of the main properties of the living, providing the possibility of their existence.

The main factors that develop the process of adaptation include: heredity, variability, natural (and artificial) selection.

Tolerance can change if the body enters other external conditions. Getting into such conditions, after a while, he gets used to it, as it were, adapts to them (from lat. adaptation - to adapt). The consequence of this is a change in the provisions of the physiological optimum.

The property of organisms to adapt to existence in a particular range of environmental factors is called ecological plasticity.

The wider the range of the ecological factor within which a given organism can live, the greater its ecological plasticity. According to the degree of plasticity, two types of organisms are distinguished: stenobiont (stenoeks) and eurybiont (euryeks). Thus, stenobionts are ecologically non-plastic (for example, flounder lives only in salt water, and crucian carp only in fresh water), i.e. short-hardy, and eurybionts are ecologically plastic, i.e. are more hardy (for example, the three-spined stickleback can live in both fresh and salt waters).

Adaptations are multidimensional, as an organism must conform to many different environmental factors at the same time.

There are three main ways of adapting organisms to environmental conditions: active; passive; avoidance of adverse effects.

The active path of adaptation is the strengthening of resistance, the development of regulatory processes that make it possible to carry out all the vital functions of the body, despite the deviation of the factor from the optimum. For example, warm-blooded animals maintain a constant body temperature - optimal for the biochemical processes occurring in it.

The passive path of adaptation is the subordination of the vital functions of organisms to changes in environmental factors. For example, under unfavorable environmental conditions, many organisms go into a state of anabiosis (hidden life), in which the metabolism in the body practically stops (winter dormancy, insect stupor, hibernation, spores persist in the soil in the form of spores and seeds).

Avoidance of adverse effects - the development of adaptations, the behavior of organisms (adaptation), which help to avoid adverse conditions. In this case, adaptations can be: morphological (the structure of the body changes: modification of the leaves of a cactus), physiological (the camel provides itself with moisture due to the oxidation of fat reserves), ethological (changes in behavior: seasonal bird migrations, hibernation in winter).

Living organisms are well adapted to periodic factors. Non-periodic factors can cause disease and even death of the organism (for example, drugs, pesticides). However, with prolonged exposure, adaptation to them may also occur.

Organisms have adapted to daily, seasonal, tidal rhythms, rhythms solar activity, moon phases and other strictly periodic phenomena. So, seasonal adaptation is distinguished as seasonality in nature and the state of winter dormancy.

Seasonality in nature. The leading value for plants and animals in the adaptation of organisms is the annual temperature variation. The period favorable for life, on average for our country, lasts about six months (spring, summer). Even before the arrival of stable frosts, a period of winter dormancy begins in nature.

Winter dormancy. Winter dormancy is not just a stoppage of development as a result of low temperatures, but a complex physiological adaptation, moreover, occurring only at a certain stage of development. For example, the malarial mosquito and the nettle moth overwinter in the adult insect stage, the cabbage butterfly in the pupal stage, and the gypsy moth in the egg stage.

Biorhythms. Each species in the process of evolution has developed a characteristic annual cycle of intensive growth and development, reproduction, preparation for winter and wintering. This phenomenon is called biological rhythm. The coincidence of each period of the life cycle with the corresponding season is crucial for the existence of the species.

The main factor in the regulation of seasonal cycles in most plants and animals is the change in the length of the day.

Biorhythms are:

exogenous (external) rhythms (arise as a reaction to periodic changes in the environment (change of day and night, seasons, solar activity) endogenous (internal rhythms) are generated by the body itself

In turn, endogenous are divided into:

Physiological rhythms (heartbeat, respiration, endocrine glands, DNA, RNA, protein synthesis, enzymes, cell division, etc.)

Ecological rhythms (daily, annual, tidal, lunar, etc.)

The processes of DNA, RNA, protein synthesis, cell division, heartbeat, respiration, etc. have rhythm. External influences can shift the phases of these rhythms and change their amplitude.

Physiological rhythms vary depending on the state of the body, while environmental rhythms are more stable and correspond to external rhythms. With endogenous rhythms, the body can navigate in time and prepare in advance for the upcoming changes in the environment - this is the biological clock of the body. Many living organisms are characterized by circadian and circanian rhythms.

Circadian rhythms (circadian) - repetitive intensities and patterns biological processes and events with a period of 20 to 28 hours. Circadian rhythms are associated with the activity of animals and plants during the day and, as a rule, depend on temperature and light intensity. For example, bats fly at dusk and rest during the day, many planktonic organisms stay at the surface of the water at night and descend into the depths during the day.

Seasonal biological rhythms are associated with the influence of light - the photoperiod. The reaction of organisms to the length of the day is called photoperiodism. Photoperiodism is a common important adaptation that regulates seasonal phenomena in the most different organisms. The study of photoperiodism in plants and animals showed that the reaction of organisms to light is based on the alternation of periods of light and darkness of a certain duration during the day. The reaction of organisms (from unicellular to humans) to the length of day and night shows that they are able to measure time, i.e. have some kind of biological clock. The biological clock, in addition to seasonal cycles, controls many other biological phenomena, determines the correct daily rhythm of both the activity of entire organisms and processes that occur even at the level of cells, in particular, cell divisions.

A universal property of all living things, from viruses and microorganisms to higher plants and animals, is the ability to give mutations - sudden, natural and artificially induced, heritable changes in the genetic material, leading to a change in certain signs of the organism. Mutational variability does not correspond to environmental conditions and, as a rule, disrupts existing adaptations.

Many insects fall into diapause (a long stop in development) at a certain stage of development, which should not be confused with a state of rest under adverse conditions. The reproduction of many marine animals is influenced by lunar rhythms.

Circanian (near-annual) rhythms are recurring changes in the intensity and nature of biological processes and phenomena with a period of 10 to 13 months.

The physical and psychological state of a person also has a rhythmic character.

The disturbed rhythm of work and rest reduces efficiency and has an adverse effect on human health. The state of a person in extreme conditions will depend on the degree of his preparedness for these conditions, since there is practically no time for adaptation and recovery.

In the biosphere, there is a global (large, or geological) circulation of substances, which existed even before the appearance of the first living organisms. It involves a wide variety of chemical elements. The geological cycle is carried out thanks to solar, gravitational, tectonic and cosmic types of energy.

With the advent of living matter, on the basis of the geological cycle, the cycle of organic matter arose - a small (biotic, or biological) cycle.

The biotic cycle of substances is a continuous, cyclic, uneven in time and space process of movement and transformation of substances that occurs with the direct participation of living organisms. It is a continuous process of creation and destruction of organic matter and is implemented with the participation of all three groups of organisms: producers, consumers and decomposers. About 40 biogenic elements are involved in biotic cycles. The cycles of carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur, iron, potassium, calcium and magnesium are of the greatest importance for living organisms.

As living matter develops, more and more elements are constantly extracted from the geological cycle and enter a new, biological cycle. total weight ash substances, involved annually in the biotic cycle of substances only on land, is about 8 billion tons. This is several times the mass of the products of the eruption of all volcanoes in the world throughout the year. The rate of circulation of matter in the biosphere is different. The living matter of the biosphere is updated on average for 8 years, the mass of phytoplankton in the ocean is updated daily. All oxygen of the biosphere passes through living matter in 2000 years, and carbon dioxide - in 300 years.

Local biotic cycles are carried out in ecosystems, and biogeochemical cycles of atomic migration are carried out in the biosphere, which not only bind all three outer shells of the planet into a single whole, but also determine the continuous evolution of its composition.

ATMOSPHERE HYDROSPHERE

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LIVING SUBSTANCE

THE SOIL

Evolution of the biosphere

The biosphere appeared with the birth of the first living organisms about 3.5 billion years ago. In the course of the development of life, it changed. The stages of evolution of the biosphere can be distinguished taking into account the characteristics of the type of ecosystems.

1. The emergence and development of life in water. The stage is associated with the existence of aquatic ecosystems. There was no oxygen in the atmosphere.

2. The emergence of living organisms on land, the development of the land-air environment and soil, and the emergence of terrestrial ecosystems. This became possible due to the appearance of oxygen in the atmosphere and the ozone screen. It happened 2.5 billion years ago.

3. The emergence of man, his transformation into a biosocial being and the emergence of anthropoecosystems occurred 1 million years ago.

4. The transition of the biosphere under the influence of intelligent human activity into a new qualitative state - into the noosphere.

Noosphere

The highest stage in the development of the biosphere is the noosphere - the stage of reasonable regulation of the relationship between man and nature. This term was introduced in 1927 by the French philosopher E. Leroy. He believed that the noosphere includes human society with its industry, language and other attributes of intelligent activity. In the 30-40s. XX century V.I. Vernadsky developed materialistic ideas about the noosphere. He believed that the noosphere arises as a result of the interaction of the biosphere and society, is controlled by the close relationship between the laws of nature, thinking and the socio-economic laws of society, and emphasized that

noosphere (sphere of the mind) - the stage of development of the biosphere, when the intelligent activity of people will become the main determining factor in its sustainable development.

The noosphere is a new, higher stage of the biosphere, associated with the emergence and development of mankind in it, which, knowing the laws of nature and improving technology, becomes the largest force comparable in scale to geological ones, and begins to have a decisive influence on the course of processes on Earth, profoundly changing it. with their labor. The formation and development of mankind was expressed in the emergence of new forms of exchange of matter and energy between society and nature, in the ever-increasing impact of man on the biosphere. The noosphere will come when humanity, with the help of science, will be able to meaningfully manage natural and social processes. Therefore, the noosphere cannot be considered a special shell of the Earth.

The science of managing the relationship between human society and nature is called noogenics.

The main goal of noogenics is the planning of the present for the sake of the future, and its main tasks are the correction of violations in the relationship between man and nature caused by the progress of technology, the conscious control of the evolution of the biosphere. A planned, scientifically substantiated use of natural resources should be formed, providing for the restoration in the cycle of substances of what has been violated by man, as opposed to a spontaneous, predatory attitude towards nature, leading to environmental degradation. This requires the sustainable development of a society that meets the needs of the present without compromising the ability of future generations to meet their own needs.

At present, the planet has formed biotechnosphere - a part of the biosphere, radically transformed by man into engineering structures: cities, factories and factories, quarries and mines, roads, dams and reservoirs, etc.

BIOSPHERE AND MAN

The biosphere for man is and habitat and source of natural resources.

Natural resources – natural objects and phenomena that a person uses in the labor process. They provide people with food, clothing, shelter. According to the degree of exhaustion, they are divided into exhaustible and inexhaustible . Exhaustible resources are divided into renewable and non-renewable . Non-renewable resources include those resources that are not revived (or are renewed hundreds of times slower than they are spent): oil, coal, metal ores and most minerals. Renewable natural resources - soil, flora and fauna, minerals (table salt). These resources are constantly being restored at different rates: animals - several years, forests - 60-80 years, soils that have lost their fertility - for several millennia. Exceeding the rate of consumption over the rate of reproduction leads to the complete disappearance of the resource.

Inexhaustible resources include water, climate ( atmospheric air and wind energy) and space: solar radiation, the energy of sea tides. However, the growing pollution of the environment requires the implementation of environmental measures to conserve these resources.

Satisfaction human needs unthinkable without the exploitation of natural resources.

All types of human activity in the biosphere can be combined into four forms.

1. Changing the structure earth's surface (plowing land, draining water bodies, deforestation, building canals). Humanity is becoming a powerful geological force. A person uses 75% of land, 15% of river waters, 20 hectares of forests are cut down every minute.

· Geological and geomorphological changes - intensification of the formation of ravines, the appearance and frequency of mudflows and landslides.

· Complex (landscape) changes - violation of the integrity and natural structure of landscapes, the uniqueness of natural monuments, loss of productive land, desertification.

All substances on our planet are in the process of circulation. Solar energy causes two cycles of matter on Earth, a large or biospheric (covering the entire biosphere), and a small or biological one (within ecosystems).

The biospheric circulation of substances was preceded by a geological one, associated with the formation and destruction of rocks and the subsequent movement of destruction products - detrital material and chemical elements. A significant role in these processes was played and continues to be played by the thermal properties of the surface of land and water: absorption into reflection sun rays, thermal conductivity to heat capacity. Water absorbs more solar energy, and the land surface in the same latitudes heats up more. The unstable hydrothermal regime of the Earth's surface, together with the planetary atmospheric circulation system, determined the geological circulation of substances, which at the initial stage of the Earth's development, along with endogenous processes, was associated with the formation of continents, oceans and modern geospheres. Its geological manifestation is also evidenced by the transfer of weathering products by air masses, and by water - mineral compounds dissolved in it. With the formation of the biosphere, the products of vital activity of organisms were included in the great cycle. The geological cycle, without ceasing its existence, has acquired new features: it is the initial stage of the biospheric movement of matter. It is he who supplies living organisms with nutrients and largely determines the conditions for their existence.

The large circulation of substances in the biosphere is characterized by two important points:

It is carried out throughout the entire geological development of the Earth;

It is a modern planetary process that takes a leading part in the further development of the biosphere (Radkevich, 1983).

At the present stage of human development, as a result of a large circulation, pollutants such as oxides of sulfur and nitrogen, dust, and radioactive impurities are also transported over long distances. The territory of temperate latitudes of the Northern Hemisphere was subjected to the greatest pollution.

A small or biological circulation of substances unfolds against the background of a large, geological one, covering the biosphere as a whole. It occurs within ecosystems, but is not closed, which is associated with the entry of matter and energy into the ecosystem from the outside and with the release of part of them into the biospheric cycle. For this reason, sometimes they talk not about the biological cycle, but about the exchange of energy in ecosystems and individual organisms.

Plants, animals and soil cover on land form a complex world system, which forms biomass, binds and redistributes solar energy, atmospheric carbon, moisture, oxygen, hydrogen, nitrogen, phosphorus, sulfur, calcium and other elements involved in the life of organisms. Plants, animals and microorganisms of the aquatic environment form another planetary system that performs the same function of binding solar energy and the biological cycle of substances.

The essence of the biological cycle is the flow of two opposite, but interrelated processes - the creation of organic matter and its destruction. The initial stage of the origin of organic matter is due to the photosynthesis of green plants, i.e. the formation of this substance from carbon dioxide, water and mineral compounds using the radiant energy of the sun. Plants extract sulfur, phosphorus, calcium, potassium, magnesium, manganese, silicon, aluminum, copper, zinc and other elements from the soil in dissolved form. Herbivorous animals already absorb compounds of these elements in the form of food of plant origin. Predators feed on herbivorous animals, consume food of a more complex composition, including proteins, fats, amino acids, etc. In the process of destruction of organic matter of dead plants and animal remains by microorganisms, simple mineral compounds available for assimilation by plants enter the soil and aquatic environment, and the next round begins biological cycle.

In contrast to the large cycle, the small one has a different duration: seasonal, annual, perennial and secular small cycles are distinguished. When studying the biological cycle of substances, the main attention is paid to the annual rhythm, determined by the annual dynamics of the development of the vegetation cover.

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A large geological cycle involves sedimentary rocks deep into the earth's crust, for a long time turning off the elements contained in them from the system of biological circulation. In the course of geological history, the transformed sedimentary rocks, once again on the surface of the Earth, are gradually destroyed by the activity of living organisms, water and air, and are again included in the biospheric cycle.

A large geological cycle occurs over hundreds of thousands or millions of years. It consists in the following: rocks are destroyed, weathered and eventually washed away by water flows into the oceans. Here they are deposited on the bottom, forming sedimentary rocks, and only partially return to land with organisms removed from the water by humans or other animals.

At the heart of a large geological cycle is the process of transferring mineral compounds from one place to another on a planetary scale without the participation of living matter.

In addition to the small circulation, there is a large, geological circulation. Some substances enter the deep layers of the Earth (through the bottom sediments of the seas or in another way), where slow transformations occur with the formation of various compounds, mineral and organic. The processes of the geological cycle are supported mainly by the internal energy of the Earth, its active core. The same energy contributes to the release of substances to the surface of the Earth. Thus, a large circulation of substances closes. It takes millions of years.

Concerning the speed and intensity of the large geological circulation of substances, at present, no matter how accurate data can be given, there are only approximate estimates, and then only for the exogenous component of the general cycle, i.e. without taking into account the influx of matter from the mantle into the earth's crust.

This carbon takes part in a large geological cycle. This carbon, in the process of a small biotic cycle, maintains the gas balance of the biosphere and life in general.

The contribution of biospheric and technospheric components to the large geological cycle of the Earth's substances is very significant: there is a constantly progressive growth of technospheric components due to the expansion of the sphere of human production activity.

Since the main technobio-geochemical flow on the earth's surface is directed within the framework of a large geological circulation of substances for 70% of the land into the ocean and for 30% - into closed drainless depressions, but always from higher to lower elevations, as a result of the action of gravitational forces, respectively, differentiation of the matter of the earth's crust from high to low elevations, from land to ocean. Reverse flows (atmospheric transport, human activity, tectonic movements, volcanism, migration of organisms) to some extent complicate this general downward movement of matter, creating local migration cycles, but do not change it in general.

The circulation of water between land and ocean through the atmosphere refers to a large geological cycle. Water evaporates from the surface of the oceans and is either transferred to land, where it falls in the form of precipitation, which again returns to the ocean in the form of surface and underground runoff, or falls in the form of precipitation to the surface of the ocean. More than 500 thousand km3 of water participate in the water cycle on Earth every year. The water cycle as a whole plays a major role in shaping the natural conditions on our planet. Taking into account the transpiration of water by plants and its absorption in the biogeochemical cycle, the entire supply of water on Earth decays and is restored in 2 million years.

According to his formulation, the biological cycle of substances develops on part of the trajectory of a large, geological cycle of substances in nature.

The transport of matter by surface and groundwater- this is the main factor in terms of land differentiation the globe geochemically, but not the only one, and if we talk about the large geological circulation of substances on the earth's surface as a whole, then flows play a very significant role in it, in particular oceanic and atmospheric transport.

Concerning the speed and intensity of the large geological circulation of substances, it is currently impossible to give any exact data, there are only approximate estimates, and then only for the exogenous component of the general cycle, i.e. without taking into account the influx of matter from the mantle into the earth's crust. The exogenous component of the large geological circulation of substances is the constantly ongoing process of denudation of the earth's surface.