The biological cycle of substances is a consistent, continuous circulation of chemical elements, which occurs due to solar radiation and is supported by a set of organisms united through food chains.
(according to the biological author edited by I.G.Pidoplichko K.M., Sitnik, 1974).
The biological cycle of substances consists of the processes of formation of organic substances from elements contained in air, soil, water and the subsequent decomposition of these substances, as a result of which the elements pass into mineral form.
The biological cycle of substances provides the necessary elements of the external and internal environment of living organisms and maintains its stability. This is, first of all, the cycle of carbon, oxygen, nitrogen, phosphorus, etc.
The cycle of substances is the repeated participation of substances in processes occurring in the atmosphere, hydrosphere and lithosphere, incl. in those layers that are part of the planet’s biosphere. Of particular importance is the circulation of biophilic elements - nitrogen, phosphorus, sulfur. (after Reimers N.F.D., 1990).
The biological cycle is a continuous, cyclical phenomenon, but uneven in time and space and accompanied by more or less significant losses of the natural redistribution of matter, energy and information within ecosystems of various hierarchical levels of organization from biogeocenosis to the biosphere (N.F. Reimers, 1990). A complete circulation of substances within the biogeocenosis does not occur because Some substances always go beyond its boundaries.
The circle of biotic exchange is large (biospheric) - a non-stop, planetary process of a natural cyclical redistribution of matter, energy, and information, uneven in time and space, repeatedly entering (except for the unidirectional flow of energy) into the continuously renewed ecological systems of the biosphere (Reimers N.F., 1990).
And here the main parameter is the environmental efficiency coefficient. The ratio of the biomass of organisms to the amount of organic matter they consume is sometimes called the environmental efficiency coefficient. This coefficient, as a rule, does not exceed 10-20.
The intensity of metabolic processes (metabolism) per unit weight of a living organism is usually greater, the smaller the organism. The reason for this pattern is the significant dependence of the metabolic process on the rate of diffusion of gases through the surface of organisms, which increases per unit of their biomass as their size decreases.
The total value of biomass for the Earth, according to estimates by V.A. Kovda (1969) = 3.10 (12), and over 95% of this value relates to plants and 5% to animals. Of all this, the bulk falls on the forests of the continents.
Assuming that the total productivity of plants on the continents is 140.10 (9) tons, we conclude that the time of one cycle of the circulation of organic matter on the continents is about 20 years. (This probably applies to forests) for others this cycle is shorter, even less for the oceans - for phytoplankton for several days). The duration of one cycle of animal organic matter circulation is several years (the total biomass of animals is about 10 (11) tons and they absorb 10% of the total productivity of plants - hence this calculation). According to data from Huxley (1962), in African savannas the biomass of large wild animals can reach 15-25 t/km2, in temperate forests - 1 t/km2, in the tundra - 0.8 t/km2 .sq.m., in semi-desert - 0.35t/km.sq.m.
The assessment of the biological mass of people and the calculation of energy consumed during their diet is calculated more accurately.
Now (with more than 4 billion people, the biomass of people is about 0.2.10^19 tons. (And now it is already more than 5 billion). A person consumes 2.5.10^3 kcal of energy daily, then the total energy consumption of people is 1.8.10 ^15kcal/year This value approximately corresponds to the modern productivity of agricultural production, i.e. in the modern era, people consume about 0.2% of the primary production of the organic world. Several thousand years ago, this figure was significantly lower than 0.01%. will still grow.
By consuming products, a person consumes technical energy, this new source of heat for our planet.
Since the process of creating organic matter is based on the absorption of carbon dioxide, often called carbon dioxide, from the atmosphere and hydrosphere by autotrophic plants, it must first be analyzed in the global biological cycle. There is about 2.3.10^12 of it in the atmosphere, i.e. 0.032% of all atmospheric air (volume %). In the hydrosphere there is more than 130.10^12 tons. It varies little in different geographical areas and with altitude. The reason is the independence of carbon dioxide content from temperature. The main components of the carbon dioxide cycle are determined by biological processes, and a little by geological ones. Consumption for photosynthesis per year is 3.10^17 (these are carbonate). The average time for the renewal of carbon dioxide in the atmosphere was about 10 years.
Now let's move on to considering individual cycles in the biosphere. The main driving force behind the cycles of matter on the planet is living matter. It is living matter, or rather its activity through a system of cycles, that ensures the progressive development of the Earth's biosphere. The cycle of matter and energy is based on two opposing processes - creation and destruction. The first ensures the formation of living matter and the accumulation of energy, the second ensures the destruction of complex organic compounds and their transformation into simple mineral ones: carbon dioxide, water, various salts, etc. The biosphere exists due to (thanks to) a continuous cycle. We have already noted earlier that the energy basis for the existence of biological cycles is the process of photosynthesis. During this process (it is in energy terms that it represents the ascending branch of the biological cycle), a huge amount of energy (solar) is stored, converted into potential chemical energy (chemical) of organic substances. The descending branch (in terms of energy) is all other life processes in which transformations of biological compounds created during photosynthesis and the use of stored energy occur. These processes end with the oxidation and mineralization of organic substances, degradation and conversion into heat of the energy stored in the chemical bonds of these substances.
The cycle of substances in nature is the most important ecological concept.
In Fig. The biological cycle is presented in combination with a simplified diagram of energy flow. Substances are involved in a cycle, and the energy flow is unidirectional from plants that convert the energy of the sun into the energy of chemical bonds, to animals that use this energy, and then to microorganisms that destroy organic substances.
The unidirectional flow of energy sets in motion the cycle of substances. Each chemical element, making a cycle in the ecosystem, alternately passes from organic to inorganic form and vice versa.
Rice. 1. Energy flow and cycle of nutrients in the biosphere
Photosynthesis– creation of organic substances (glucose, starch, cellulose, etc.) from carbon dioxide and water with the participation of chlorophyll under the influence of solar energy:
6CO 2 + 12H 2 O + hν (673 kcal) = C 6 H 12 O 6 + 6O 2 + 6H 2 O
Photosynthesis is the process of capturing solar energy by photosynthetic organisms and converting it into biomass energy.
Every year, the plant world stores free energy 10 times higher than the amount of mineral energy consumed per year by the entire population of the Earth. These minerals themselves (coal, oil and natural gas) are also products of photosynthesis that occurred millions of years ago.
Every year, photosynthesis absorbs 200 billion tons of carbon dioxide and releases up to 320 billion tons of oxygen. All atmospheric carbon dioxide passes through living matter in 6-7 years.
In the biosphere, processes of destruction of organic matter to the simplest molecules also occur: CO 2, H 2 O, NH 3. The decomposition of organic compounds occurs in animal organisms and in plants during the process of respiration with the formation of CO 2 and H 2 O.
Mineralization of organic substances, the decomposition of dead organic matter into simple inorganic compounds occurs under the influence of microorganisms.
The opposite processes of formation and destruction of organic matter in the biosphere form a single biological cycle of atoms. During the mineralization of organic compounds, energy that was absorbed during photosynthesis is released. It is released as heat and also as chemical energy.
Biological cycleis a set of processes of the entry of chemical elements into living organisms, the biosynthesis of new complex compounds and the return of elements to the soil, atmosphere and hydrosphere.
The intensity of the biological cycle (BIC) is determined by the ambient temperature and the amount of water. The biological cycle is more intense in tropical rainforests than in the tundra.
The most important result of the biological cycle of substances is the formation of a humus soil horizon on land.
The biological cycle is characterized by the following indicators.
Biomass - the mass of living matter accumulated at a given point in time (phyto-, zoo-, microbiomass).
Plant biomass(phytomass) - the mass of living and dead plant organisms.
Decay - the amount of organic matter of plants that died per unit area per unit of time.
Growth- biomass accumulated per unit area per unit time.
The chemical composition of plants depends on two main factors:
1) ecological, - plant growth conditions, - levels of elements in the environment, forms of presence, including mobile ones, accessible to plants;
2) genetic, in connection with the peculiarities of the origin of the plant species.
In conditions of environmental pollution, the concentration of elements in plants is determined by the first factor. In background (undisturbed) landscapes, both factors are important.
Depending on the reaction to the chemical factor of the environment (the content of chemical elements), two groups of plants can be distinguished:
1) adapted to changes in the concentration of chemical elements;
2) not adapted to changes in the concentration of chemical elements.
Changes in the concentrations of chemical elements in the environment in non-adapted plants cause physiological disturbances leading to diseases; plant development is inhibited and the species becomes extinct.
Some plant species appear to be well adapted to tolerate high concentrations of elements. These are wild plants that grow in a given area for a long time, which, as a result of natural selection, acquire resistance to unfavorable living conditions.
Plants that concentrate chemical elements are called concentrators. For example: sunflowers and potatoes concentrate potassium, tea – aluminum, mosses – iron. Wormwood, horsetail, corn, and oak accumulate gold.
BIOLOGICAL CYCLE OF SUBSTANCES The entry of substances from the soil and atmosphere into living organisms with a corresponding change in their chemical form, their return to the soil and atmosphere during the vital activity of organisms and with post-mortem residues, and their re-entry into living organisms after processes of destruction and mineralization with the help of microorganisms
Dictionary of business terms. Akademik.ru. 2001.
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12.1. The concept of biological circulation
The biological cycle is a cycle of chemical elements and substances that arose simultaneously with the appearance of life on Earth, carried out by the vital activity of organisms. It plays a special role in the biosphere. On this occasion, N.V. Timofeev-Resovsky wrote: “There is a huge, eternal, constantly working biological cycle in the biosphere, a number of substances, a number of forms of energy constantly circulate in this large cycle of the biosphere” (M. M. Kamshilov, 1974; V. A. Vronsky, 1997). The laws of the biological cycle solve the problem of the long-term existence and development of life. On a body of finite volume, such as the Earth, the reserves of available mineral elements necessary to carry out the function of life cannot be infinite. If they were only consumed, life would sooner or later have to end. “The only way to give a limited quantity the property of infinity,” writes W. R. Williams, “is to make it rotate along a closed curve.” Life used exactly this method. “Green plants create organic matter, non-green plants destroy it. From mineral compounds obtained from the breakdown of organic matter, new green plants build new organic matter, and so on endlessly.” Taking this into account, each type of organism represents a link in the biological cycle. Using the bodies or decay products of some organisms as means of subsistence, he must give into the environment something that others can use. The role of microorganisms is especially important. Mineralizing the organic remains of animals and plants, microorganisms transform them into a “single currency” - mineral salts and simple organic compounds such as biogenic stimulants, which are again used by green plants in the synthesis of new organic matter. One of the main paradoxes of life is that its continuity is ensured by processes of decay and destruction. Complex organic compounds are destroyed, energy is released, and the supply of information characteristic of complexly organized living bodies is lost. As a result of the activity of destructors, mainly microorganisms, any form of life will inevitably be included in the biological cycle. Therefore, with their help, natural self-regulation of the biosphere is carried out. Two properties allow microorganisms to play such an important role: the ability to adapt relatively quickly to different conditions and the ability to use a wide variety of substrates as a source of carbon and energy. Higher organisms do not have such abilities. Therefore, they can exist only as a kind of superstructure on a solid foundation of microorganisms. The biological cycle, based on the interaction of synthesis and destruction of organic matter, is one of the most significant forms of organization of life on a planetary scale. Only he ensures the continuity of life and its progressive development.
Individuals and species of organisms of different systematic groups act as links in the biological cycle, interacting with each other directly and indirectly through numerous and multilateral direct and feedback connections. The biological cycle of the planet also appears to be a complex system of private cycles - ecological systems interconnected by various forms of interaction.
The biological cycle occurs mainly through trophic (food) chains (Figure 12.1).
Given the important role of plants and animals in it, the flow of nutrients such as nitrogen, phosphorus, sulfur through populations of microorganisms in the cycle is approximately an order of magnitude higher than through populations of plants and animals. An important indicator of the intensity of the biological cycle is the rate of circulation of chemical elements. As an indicator of this intensity, one can use the rate of accumulation and decomposition of dead organic matter resulting from the annual fall of leaves and the death of organisms.
The ratio, for example, of the mass of litter to that part of the litter that forms the litter serves as an indicator of the rate of decomposition of litter and the release of chemical elements. The higher this index, the lower the intensity of the biological cycle in a given ecosystem. The highest index value (more than 50) is characterized by swampy forests and tundra. In dark coniferous forests the index is 10–17, in broad-leaved forests – 3–4, in steppes – 1.0–1.5, in savannas – no more than 0.2. In tropical rainforests, plant residues practically do not accumulate (index no more than 0.1). Therefore, here the biological cycle is most intense.
^ BIOLOGICAL CYCLE OF SUBSTANCES IN NATURE
General concept of the biological cycle of substances
Biological cycle of substances as a form of development of planet Earth
Elements of the biogeochemical cycle of substances in nature
Parameters of the biogeochemical cycle on land
Biological cycle and soil formation
^ GENERAL CONCEPT
The biological cycle of substances is a set of processes of the entry of chemical elements from the soil and atmosphere into living organisms, the biochemical synthesis of new complex compounds and the return of elements to the soil and atmosphere with the annual decline of part of the organic matter. The biological cycle of substances is not a fully compensated closed cycle, therefore, during its course, the soil is enriched with humus and nitrogen, mineral nutrition elements (the so-called nutrients), which creates a favorable basis for the existence of plant organisms.
The biological, biochemical and geochemical significance of the processes carried out in the biological cycle of substances was first shown by V.V. Dokuchaev, creating the doctrine of natural zones. It was further revealed in the works of V. I. Vernadsky, B. B. Polynov, D. N. Pryanishnikov, V. N. Sukachev, N. P. Remezov, L. E. Rodin, N. I. Bazilevich, V. A. Kovda and other researchers.
The International Union of Biological Sciences has carried out a broad program of research into the biological productivity of biogeocenoses on land and in water bodies. The International Biological Program was created to guide this research. In order to unify the terms and concepts used in modern literature, certain work has been carried out on the International Bioprogram. Before we begin to study natural biological cycles of substances, it is necessary to provide explanations for the most commonly used terms.
Biomass - the mass of living matter accumulated at a given point in time.
^ Plant biomass (synonym - phytomass) - the mass of living and dead organisms of plant communities on any area that have retained their anatomical structure at a given moment.
^ Biomass structure - the ratio of underground and aboveground parts of plants, as well as annual and perennial, photosynthetic and non-photosynthetic parts of plants.
Rags - dead parts of plants that have retained a mechanical connection with the plant.
^ Fall - the amount of organic matter of plants that died in above-ground and underground parts per unit area per unit of time.
Litter - a mass of perennial deposits of plant residues of varying degrees of mineralization.
Growth - the mass of an organism or community of organisms accumulated per unit area per unit of time.
^ True growth - the ratio of the amount of growth to the amount of litter per unit time per unit area.
Primary production - the mass of living matter created by autotrophs (green plants) per unit area per unit time.
^ Secondary products - the mass of organic matter created by heterotrophs per unit area per unit time.
Capacity of the biological cycle - the amount of chemical elements contained in the mass of a mature biocenosis (phytocenosis).
The intensity of the biological cycle is the number of chemical elements contained in the growth of phytocenosis per unit area per unit time.
The rate of biological turnover is the period of time during which an element travels from its absorption by living matter to its release from living matter. Determined using labeled atoms.
According to L. E. Rodin and N. I. Bazilevich (1965), the full cycle of the biological cycle of elements consists of the following components.
Absorption by the assimilating surface of plants from the atmosphere of carbon, and by root systems from the soil - nitrogen, ash elements and water, fixing them in the bodies of plant organisms, entering the soil with dead plants or their parts, decomposition of litter and release of the elements contained in them.
The alienation of parts of plants by animals that feed on them, their transformation in the bodies of animals into new organic compounds and the fixation of some of them in animal organisms, their subsequent entry into the soil with the excrement of animals or with their corpses, the decomposition of both of them and the release of the elements contained in them.
Gas exchange between the assimilating surface of plants and the atmosphere, between the root system and soil air.
Lifetime secretions of certain elements by above-ground plant organs and especially by root systems directly into the soil.
^ BIOLOGICAL CYCLE OF SUBSTANCES AS A FORM OF DEVELOPMENT OF PLANET EARTH
The structure of the biosphere in its most general form consists of two largest natural complex of the first rank - continental and oceanic. Plants, animals and soil cover form a complex global ecological system on land. By binding and redistributing solar energy, atmospheric carbon, moisture, oxygen, hydrogen, nitrogen, phosphorus, sulfur, calcium and other biophilic elements, this system forms biomass and generates free oxygen.
Aquatic plants and the ocean form another global ecological system that performs the same functions on the planet of binding solar energy, carbon, nitrogen, phosphorus and other biophiles through the formation of phytobiomass and the release of oxygen into the atmosphere.
There are three forms of accumulation and redistribution of cosmic energy in the biosphere. ^ The essence of the first One of them is that plant organisms, and through food chains and associated animals and bacteria, involve many compounds in their tissues. These compounds contain H 2, O 2, N, P, S, Ca, K, Mg, Si, Al, Mn and other biophiles, many trace elements (I, Co, Cu, Zn, etc.). In this case, there is a selection of light isotopes (C, H, O, N, S) from heavier ones. Intravital and postmortem organisms of land, aquatic and air environments, being in a state of continuous exchange with the environment, perceive and release a wide and varied range of mineral and organic compounds. The total mass and volume of the products of intravital metabolism of organisms and the environment (metabolites) exceed the biomass of living matter several times.
^ Second form accumulation, retention and redistribution of the cosmic energy of the Sun on the planet in its biosphere is manifested through the heating of water masses, the formation and condensation of vapors, precipitation and the movement of surface and groundwater along the slope from areas of nutrition to areas of evaporation. Uneven heating of air and water causes planetary movements of water and air masses, the formation of density and pressure gradients, ocean currents and enormous processes of atmospheric circulation.
Erosion, chemical denudation, transport, redistribution, deposition and accumulation of mechanical and chemical sediments on land and in the ocean are the third form of transfer and transformation of this energy.
All these three planetary processes are closely intertwined; forming a global circulation and a system of local circulations of matter. Thus, over billions of years of the biological history of the planet, a great biogeochemical cycle and differentiation of chemical elements in nature have developed. They created the modern biosphere and are the basis for its normal functioning.
^ ELEMENTS OF BIOGEOCHEMICAL CYCLE OF SUBSTANCES IN NATURE
The elements of the biogeochemical cycle of substances are the following components.
Regularly repeating or continuously ongoing processes of energy flow, formation and synthesis of new compounds.
Constant or periodic processes of transfer or redistribution of energy and processes of removal and directional movement of synthesized compounds under the influence of physical, chemical and biological agents.
Directed rhythmic or periodic processes of sequential transformation: decomposition, destruction of previously synthesized compounds under the influence of biogenic or abiogenic environmental influences.
In nature, both biological cycles of substances and abiogenic cycles occur.
^ Biological cycles - conditioned at all levels vital activity of organisms (nutrition, food connections, reproduction, growth, movement of metabolites, death, decomposition, mineralization).
^ Abiogenic cycles - formed on the planet much earlier than biogenic ones. They include the entire complex of geological, geochemical, hydrological, and atmospheric processes.
In the prebiogenic period of the planet, water and air migration and accumulation played a decisive role in geological, hydrological, geochemical, and atmospheric cycles. In the conditions of a developed biosphere, the circulation of substances is directed by the combined action of biological, geological and geochemical factors. The relationship between them may be different, but the action must be joint! It is in this sense that the terms are used - biogeochemical circulation of substances, biogeochemical cycles.
Undisturbed biogeochemical cycles are almost circular, almost closed. The degree of repeated reproduction of cycles in nature is very high and, probably, according to V. A. Kovda, reaches 90-98%. This maintains a certain constancy and balance in the composition, quantity and concentration of components involved in the cycle, as well as the genetic and physiological fitness and harmony of organisms and the environment. But the incomplete closure of biogeochemical cycles in geological time leads to the migration and differentiation of elements and their compounds in space and in various environments, to the concentration or dispersion of elements. That is why we observe the biogenic accumulation of nitrogen and oxygen in the atmosphere, the biogenic and chemogenic accumulation of carbon compounds in the earth's crust (oil, coal, limestone).
^ PARAMETERS OF BIOGEOCHEMICAL CYCLE ON LAND
Mandatory parameters for studying biogeochemical cycles in nature are the following indicators.
Biomass and its actual growth (phyto-, zoo-, microbial mass separately).
Organic litter (quantity, composition).
Soil organic matter (humus, undecomposed organic matter).
Elemental material composition of soils, waters, air, sediments, biomass fractions.
Aboveground and underground reserves of biogenic energy.
Lifetime metabolites.
Number of species, abundance, composition.
Life expectancy of species, dynamics and rhythm of life of populations and soils.
Ecological and meteorological environment: background and assessment of human intervention.
Coverage of watersheds, slopes, terraces, river valleys, lakes with observation points.
The amount of pollutants, their chemical, physical, biological properties (especially CO, CO 2, SO 2, P, NO 3, NH 3 Hg, Pb, Cd, H 2 S, hydrocarbons).
1. Content of ash substances, carbon and nitrogen in biomass (aboveground, underground, phyto-, zoo-, microbial). The content of these elements can be expressed in % or in g/m2, t/ha of surface. The main constituent elements of living matter by weight are O (65-70%) and H (10%). All the rest account for 30-35%: C, N, Ca (1-10%); S, P, K, Si (0.1-1%); Fe, Na, Cl, Al, Mg (0.01-0.1%).
The chemical composition of phytomass varies greatly. The composition of the phytomass of coniferous and deciduous forests, herbaceous vegetation and halophytes is especially different (Table 13).
Table 13 - Mineral composition of various groups of sushi plants
| Vegetation type | Ash content, % | Annual turnover of minerals Components, kg/ha | Predominant components |
| Coniferous forests | 3-7 | 100-300 | Si, Ca, P, Mg, K |
| Deciduous forests | 5-10 | 460-850 | Ca, K, P, Al, Si |
| Rainforests | 3-4 | 1000-2000 | Ca, K, Mg, Al |
| Meadows, steppes | 5-7 | 800-1200 | Si, Ca, K, S, P |
| Halophytic communities | 20-45 | 500-1000 | Cl, SO 4, Na, Mg, K |
The individual significance of a particular chemical element is assessed by the biological absorption coefficient (BAC). It is calculated using the formula:
In 1966, V. A. Kovda proposed using the ratio of the recorded phytobiomass to the annual photosynthetic increase in phytomass to characterize the average duration of the general carbon cycle. This coefficient characterizes the average duration of the general cycle of synthesis - mineralization of biomass in a given area (or on land in general). Calculations have shown that for land as a whole this cycle fits into a period of 300-400 and no more than 1000 years. Accordingly, at this average speed, the release of mineral compounds bound in biomass occurs, the formation and mineralization of humus in the soil.
For a general assessment of the biogeochemical significance of the mineral components of the living matter of the biosphere, V. A. Kovda proposed to compare the reserve of mineral substances of the biomass, the amount of mineral substances annually involved in circulation with growth and litter, with the annual chemical runoff of rivers. It turned out that these values are close: 10 8-9 ash substances are involved in growth and litter, and 10 9 - in the annual chemical runoff of rivers.
BGKhK index = S b / S X,
Where S b is the sum of elements (or the amount of one element) in the annual increase in biomass; S x is the sum of the same elements (or one element) carried out by the waters of the rivers of a given basin (or part of a basin).
It turned out that biogeochemical turnover indices vary greatly in different climatic conditions, under the cover of different plant communities, and under different conditions of natural drainage.
4. N.I. Bazilevich, L.E. Rodin (1964) proposed calculating a coefficient characterizing the intensity of litter decomposition and the duration of litter preservation under the conditions of a given biogeocenosis:
According to N.I. Bazilevich and L.E. Rodin, the indices of the intensity of phytomass decomposition are greatest in the tundra and swamps of the north, the smallest (approximately equal to 1) in the steppes and semi-deserts.
5. B.B. Polynov (1936) proposed calculating the water migration index:
IVM = X H2O / X zk,
Where IWM is the water migration index; X H2O - the amount of the element in the mineral residue of evaporated river or ground water; X зк - content of the same element in the earth's crust or rock.
Calculation of water migration indices showed that the most mobile migrants in the biosphere are Cl, S, B, Br, I, Ca, Na, Mg, F, Sr, Zn, U, Mo. The most passive in this regard are Si, K, P, Ba, Mn, Rb, Cu, Ni, Co, As, Li, Al, Fe.
^ BIOLOGICAL CYCLE AND SOIL FORMATION
Data from geology and paleobotany allowed V.A. Kovda to present in general terms the most important stages in the development of the soil-forming process in connection with the history of the development of plants and vegetation cover (1973). The beginning of the soil-forming process on Earth is associated with the appearance of autotrophic bacteria capable of independent existence in the most unfavorable hydrothermal conditions. This initial process of the influence of lower organisms on the rocks of the earth's crust was called by V. R. Williams the primary soil-forming process. Autotrophic bacteria, discovered by S. N. Vinogradov at the end of the 19th century, are the simplest single-celled organisms, numbering about a hundred species. They have the ability to reproduce very quickly: 1 individual can produce trillions of organisms within 24 hours. Modern autotrophs include sulfur bacteria, iron bacteria, etc., which play an extremely important role in intrasoil processes. The appearance of autotrophic bacteria apparently dates back to the Precambrian.
Thus, the first synthesis of organic matter and biological cycles of C, S, N, Fe, Mn, O 2, H 2 in the earth's crust were associated with the activity of autotrophic bacteria using the oxygen of mineral compounds. In the emergence of the soil-forming process, perhaps, along with autotrophic bacteria, non-cellular life forms such as viruses and bacteriophages also played some role. Of course, this was not a soil-forming process in its modern form, since there were no root plants, there were no accumulations of humus compounds and no biogenic mechanism. And, apparently, it is more correct to talk about the primary biogeochemical weathering of rocks under the influence of lower organisms.
Single-celled blue-green algae appeared in the Precambrian. Multicellular algae - green, brown, crimson - spread from the Silurian and Devonian. The soil-forming process became more complex and accelerated, the synthesis of organic matter began in noticeable quantities, and there was an expansion of the small biological cycle of O, H, N, S and other nutrients. Apparently, according to V.A. Kovda, the soil-forming process at these stages was accompanied by the accumulation of biogenic fine earth. The stage of initial soil formation was very long and was accompanied by a slow but continuous accumulation of biogenic fine earth, enriched in organic matter and elements involved in the biological cycle: H, O, C, N, P, S, Ca, K, Fe, Si, A1. At this stage, biogenic synthesis of secondary minerals could already take place: aluminum and ferrisilicates, phosphates, sulfates, carbonates, nitrates, quartz, and soil formation was confined to shallow areas. On land it had a rocky and swampy character.
In the Cambrian, psilophytes also appeared - low-growing shrub-type plants that did not even have roots. They received some distribution in the Silurian and significant development in the Devonian. At the same time, horsetails and ferns appear - inhabitants of wet lowlands. Thus, a relatively developed form of the soil-forming process began with the Silurian and Devonian, i.e. about 300-400 million years ago. However, no turf process was observed, since there was no herbaceous vegetation. The ash content of ferns and mosses is not high (4-6%), horsetails are much higher (20%). The ash composition was dominated by K (30%), Si (28%) and C1 (10%). Fungal microflora contributed to the involvement of P and K in the biological cycle, and lichens - Ca, Fe, Si. The formation of acidic soils (kaolinite allite, bauxite) and hydromorphic soils enriched with iron compounds is likely.
A developed soil-forming process apparently developed only at the end of the Paleozoic (Carboniferous, Permian). It is to this time that scientists attribute the appearance of continuous vegetation cover on land. In addition to ferns, mosses, and horsetails, gymnosperms appeared. Landscapes of forests and swamps predominated, and a zonal climate was formed against the backdrop of the dominance of warm tropical and subtropical climates. Consequently, swamp and forest tropical soil-forming processes predominated during this period.
This regime continued until approximately the middle of the Permian period, when the climate gradually became colder and dryer. Dryness and cooling contributed to the further development of zonation. It was during this period (second half of the Permian, Triassic) that gymnospermous coniferous plants developed widely. In high latitudes at this time the formation of acidic podzolic soils took place, in low latitudes soil formation followed the development of yellow soils, red soils, and bauxites. Low ash content (about 4%), insignificant content of Cl, Na, high content of Si (16%), Ca (2%), S (6%), K (6.5%) in pine needle ash led to increased participation in biological the role of Ca, S, P in the cycle and in soil formation and the decreasing role of Si, K, Na, C1.
In the Jurassic, diatoms appear, and in the following Cretaceous period, angiosperms flowering plants appear. From the middle of the Cretaceous period, deciduous species became widespread - maple, oak, birch, willow, eucalyptus, walnut, beech, and hornbeam. Under their canopy, the podzol formation process begins to weaken, since the composition of the litter of these plants contains a large proportion of Ca, Mg, and K.
In the Tertiary era, tropical flora predominated on the globe: palm trees, magnolias, sequoia, beech, chestnut. The mineral composition of substances involved in the cycle by these forests was characterized by a significant participation of Ca, Mg, K, P, S, Si, and Al. This created the ecological prerequisites for the appearance and development of herbaceous vegetation: a decrease in the acidity of soils and rocks, and the accumulation of nutrients.
The change in the dominance of woody vegetation to herbaceous vegetation was of enormous fundamental importance in changing the nature of soil-forming processes. The powerful root system of trees involved a significant mass of mineral substances in the biological cycle, mobilizing them for the subsequent settlement of herbaceous vegetation. The short life of herbaceous vegetation and the concentration of root masses in the uppermost layers of the soil provide, under the cover of grasses, a spatial concentration of the biological cycle of mineral substances in a thinner layer of horizons with the accumulation of ash nutrition elements in them. Thus, starting from the 2nd half of the Cretaceous period, in the Tertiary and especially in the Quaternary periods, under the influence of the dominance of herbaceous vegetation, the soddy process of soil formation spread.
So, the role of living matter and the biological cycle in the geological history of the Earth and the development of the soil-forming process has continuously increased. But soil formation gradually became one of the main links in the biological cycle of substances.
The soil ensures the constant interaction of large geological and small biological cycles of substances on the earth's surface. Soil is a connecting link and regulator of the interaction between these two global cycles of matter.
Soil - accumulates organic matter and the associated chemical energy, chemical elements, thereby regulating the speed of the biological cycle of substances.
The soil, having the ability to dynamically reproduce its fertility, regulates biosphere processes. In particular, the density of life on Earth, along with climatic factors, is largely determined by the geographical heterogeneity of the soil.
