Biological (small) cycle - the circulation of substances between plants, wildlife, microorganisms and soil. Its basis is photosynthesis, i.e., the conversion by green plants and special microorganisms of the radiant energy of the Sun into the energy of chemical bonds of organic substances. Photosynthesis provided oxygen on Earth with the help of green organisms, the ozone layer and the conditions for biological evolution.[...]
The small biological cycle of substances is especially important in soil formation, since it is the interaction of biological and geological cycles that underlies the soil-forming process.[...]
The nitrogen cycle is currently highly impacted by humans. On the one hand, mass production of nitrogen fertilizers and their use lead to excessive accumulation of nitrates. Nitrogen supplied to fields in the form of fertilizers is lost through crop waste, leaching and denitrification. On the other hand, when the rate of conversion of ammonia into nitrates decreases, ammonium fertilizers accumulate in the soil. It is possible to suppress the activity of microorganisms as a result of soil contamination with industrial waste. However, all these processes are quite local in nature. Much more important is the entry of nitrogen oxides into the atmosphere during fuel combustion at thermal power plants and in transport. Nitrogen “fixed” in industrial emissions is toxic, unlike biologically fixed nitrogen. During natural processes, nitrogen oxides appear in the atmosphere in small quantities as intermediate products, but in cities and industrial areas their concentrations become dangerous. They irritate the respiratory system, and under the influence of ultraviolet radiation, reactions occur between nitrogen oxides and hydrocarbons with the formation of highly toxic and carcinogenic compounds.[...]
Cycles as a form of movement of matter are also inherent in the biostrome, but here they acquire their own characteristics. The horizontal cycle is represented by a triad: birth - reproduction - death (decomposition); vertical - by the process of photosynthesis. Both of them, in the formulation of A.I. Perelman (1975), find unity in a small biological cycle: “... chemical elements in the landscape make cycles, during which they repeatedly enter living organisms (“organize”) and leave them ( “mineralized”)”2.[...]
Biological cycle (biotic) is a phenomenon of continuous, cyclical, natural, but uneven in time and space redistribution of matter, energy1 and information within ecological systems of various hierarchical levels of organization - from biogeocenosis to the biosphere. The circulation of substances on the scale of the entire biosphere is called a large circle (Fig. 6.2), and within a specific biogeocenosis - a small circle of biotic exchange.[...]
Any biological cycle is characterized by the repeated inclusion of atoms of chemical elements in the bodies of living organisms and their release into the environment, from where they are again captured by plants and drawn into the cycle. A small biological cycle is characterized by capacity - the number of chemical elements simultaneously present in living matter in a given ecosystem, and speed - the amount of living matter formed and decomposed per unit time.[...]
The small biological cycle of substances is based on the processes of synthesis and destruction of organic compounds with the participation of living matter. Unlike the large one, the small cycle is characterized by an insignificant amount of energy.[...]
On the contrary, the biological cycle of matter takes place within the boundaries of the inhabited biosphere and embodies the unique properties of the living matter of the planet. Being part of a large, small cycle is carried out at the level of biogeocenosis, it consists in the fact that soil nutrients, water, carbon are accumulated in the substance of plants, spent on building the body and life processes of both themselves and organisms - consumers. The products of decomposition of organic matter by soil microflora and mesofauna (bacteria, fungi, mollusks, worms, insects, protozoa, etc.) are again decomposed into mineral components, again accessible to plants and therefore again involved by them in the flow of matter. [...]
The described circulation of substances on Earth, supported by solar energy - the circular circulation of substances between plants, microorganisms, animals and other living organisms - is called the biological cycle of substances, or the small cycle. The time for complete metabolism of a substance through a small cycle depends on the mass of this substance and the intensity of the processes of its movement through the cycle and is estimated at several hundred years.[...]
There are large and small - (biological) cycles of matter in nature, the water cycle. [...]
Despite the relatively small thickness of the layer of water vapor in the atmosphere (0.03 m), it is atmospheric moisture that plays the main role in the circulation of water and its biogeochemical cycle. In general, for the entire globe there is one source of water influx - precipitation - and one source of flow - evaporation, amounting to 1030 mm per year. In the life of plants, a huge role of water belongs to the processes of photosynthesis (the most important link in the biological cycle) and transpiration. Evapotranspiration, or the mass of water evaporated by woody or herbaceous vegetation or the soil surface, plays an important role in the water cycle on the continents. Groundwater, penetrating through plant tissue during the process of transpiration, introduces mineral salts necessary for the life of the plants themselves. [...]
On the basis of the large geological cycle, a small cycle of organic substances arose, which was based on the processes of synthesis and destruction of organic compounds. These two processes ensure life on Earth. The energy of the biological cycle makes up only 1% of the solar energy captured by the Earth, but it is this energy that does enormous work in creating living matter.[...]
Solar energy provides two cycles of substances on Earth: geological, or large, and small, biological (biotic).[...]
Destabilization of the nitrification process disrupts the entry of nitrates into the biological cycle, the amount of which determines the response to changes in the environment of the denitrifier complex. Enzyme systems of denitrifiers reduce the rate of complete recovery, involving less nitrous oxide in the final stage, the implementation of which requires significant energy costs. As a result, the content of nitrous oxide in the above-ground atmosphere of eroded ecosystems reached 79 - 83% (Kosinova et al., 1993). The alienation of some organic matter from chernozems under the influence of erosion is reflected in the replenishment of the nitrogen fund during photo- and heterotrophic nitrogen fixation: aerobic and anaerobic. At the first stages of erosion, precisely anaerobic nitrogen fixation is suppressed at a rapid pace due to the parameters of the labile part of organic matter (Khaziev, Bagautdinov, 1987). The activity of the enzymes invertase and catalase in heavily washed away chernozems decreased by more than 50% compared to unwashed ones. In gray forest soils, as their erosion increases, invertase activity decreases most sharply. If in weakly eroded soils there is a gradual attenuation of activity with depth, then in heavily eroded soils, invertase activity is very small or not detected in the subsoil layer. The latter is associated with the emergence of illuvial horizons with extremely low enzyme activity on the day surface. There was no clear dependence on the activity of phosphatase and, especially, catalase on the degree of soil erosion (Lichko, 1998).[...]
The geochemistry of the landscape reveals the hidden, deepest side of the small geographic circulation of matter and energy. The concept of a small geographic circulation has not yet been sufficiently developed in physical geography. In general, it can be represented as a multi-string not completely closed circular flow, consisting of incoming and emitted heat, the biological cycle of chemical elements, a small water cycle (precipitation - evaporation, above-ground and underground runoff and inflow), aeolian migration - bringing in and taking out - mineral substance.[...]
The weakening of the turf soil formation process is due to the low intensity of the biological cycle and low productivity of vegetation. Annual litter with a total biomass of about 100 t/ha does not exceed 0.4-0.5 t/ha. The bulk of litter is represented by root remains. About 70 kg/ha of nitrogen and 300 kg/ha of ash elements are involved in the biological cycle.[...]
Tropical rainforests are quite ancient climax ecosystems in which the cycle of nutrients is brought to perfection - they are little lost and immediately enter the biological cycle carried out by mutualistic organisms and shallow, mostly aerial, with powerful mycorrhiza, tree roots. It is thanks to this that forests grow so luxuriantly on poor soils.[...]
The formation of the chemical composition of the soil is carried out under the influence of the large geological and small biological cycle of substances in nature. Elements such as chlorine, bromine, iodine, sulfur, calcium, magnesium, and sodium are most easily removed from the soil.[...]
Due to the high activity of biogeochemical processes and the colossal volumes and scales of substance turnover, biologically significant chemical elements are in constant cyclic movement. According to some estimates, if we assume that the biosphere has existed for at least 3.5-4 billion years, then all the water in the World Ocean has gone through the biogeochemical cycle at least 300 times, and the free oxygen of the atmosphere at least 1 million times. The cycle of carbon occurs in 8 years, nitrogen in 110 years, oxygen in 2500 years. The bulk of carbon, concentrated in carbonate sediments of the ocean floor (1.3 x 1016 tons), other crystalline rocks (1 x 1016 tons), coal and oil (0.34 x 1016 tons), participates in the great cycle. Carbon contained in plant (5 x 10 mt) and animal tissues (5 x 109 t) participates in the small cycle (biogeochemical cycle).[...]
However, on land, in addition to precipitation brought from the ocean, evaporation and precipitation occur through the water cycle closed on land. If the biota of the continents did not exist, then these additional land sediments would be much less than the sediments brought in from the ocean. Only the formation of vegetation and soil leads to a large amount of evaporation from the land surface. With the formation of vegetation, water accumulates in the soil, plants and the continental part of the atmosphere, which leads to an increase in the closed circulation on land. Currently, precipitation on land is on average three times greater than river flow. Consequently, only one third of precipitation comes from the ocean and more than two thirds is provided by the closed water cycle on land. Thus, water on land becomes biologically accumulated; the main part of the water regime of land is formed by biota and can be regulated biologically. [...]
It is convenient to identify some of the main features of the manifestation of the first and second forces, based on the idea of the action of matter cycles on the Earth: large - geological (geocyre) and small - biological (biological cycle).[...]
Plant communities of the southern taiga are more resistant to chemical pollution compared to communities of the northern taiga. The low stability of northern taiga cenoses is due to their low species diversity and simpler structure, the presence of species sensitive to chemical pollution (mosses and lichens), low productivity and capacity of the biological cycle, and lower ability to recover.[...]
However, any ecosystem, regardless of size, includes a living part (biocenosis) and its physical, that is, inanimate, environment. At the same time, small ecosystems are part of increasingly larger ones, up to the global ecosystem of the Earth. Similarly, the general biological cycle of matter on the planet also consists of the interaction of many smaller, private cycles.[...]
Soil is an integral component of terrestrial biogeocenoses. It carries out the conjugation (interaction) of large geological and small biological cycles of substances. Soil is a unique natural formation with a complex material composition. Soil matter is represented by four physical phases: solid (mineral and organic particles), liquid (soil solution), gaseous (soil air) and living (organisms). Soils are characterized by complex spatial organization and differentiation of characteristics, properties and processes.[...]
According to the first corollary, we can only count on low-waste production. Therefore, the first stage in the development of technologies should be their low resource intensity (both at the input and output - economy and insignificant emissions), the second stage will be the creation of cyclical production (waste of some can be raw materials for others) and the third - the organization of reasonable disposal of inevitable residues and neutralization of irremovable energy waste. The idea that the biosphere operates on the principle of non-waste is erroneous, since it always accumulates substances removed from the biological cycle that form sedimentary rocks.[...]
The essence of soil formation according to V.R. Williams is defined as the dialectical interaction of the processes of synthesis and decomposition of organic matter, occurring in the system of small biological cycle of substances.[...]
At different stages of the development of the biosphere, the processes in it were not the same, despite the fact that they followed similar patterns. The presence of a pronounced cycle of substances, according to the law of global closure of the biogeochemical cycle, is a mandatory property of the biosphere at any stage of its development. This is probably an immutable law of its existence. Particular attention should be paid to the increase in the share of the biological, rather than geochemical, component in the closure of the biogeochemical cycle of substances. If at the first stages of evolution the general biosphere cycle prevailed - a large biosphere circle of exchange (at first only within the aquatic environment, and then divided into two subcycles - land and ocean), then later it began to fragment. Instead of a relatively homogeneous biota, ecosystems of various levels of hierarchy and geographic dislocation appeared and became increasingly differentiated. Small, biogeocenotic, exchange circles have acquired importance. The so-called “exchange of exchanges” arose - a harmonious system of biogeochemical cycles with the highest importance of the biotic component.[...]
In mid-latitudes, the energy input from the Sun is 48-61 thousand GJ/ha per year. When adding additional energy of more than 15 GJ/ha per year, unfavorable processes for the environment arise - soil erosion and deflation, siltation and pollution of small rivers, eutrophication of water bodies, disturbances of the biological cycle in ecosystems.[...]
The East Siberian region is characterized by severe winters with little snow and mainly summer precipitation that washes the soil layer. As a result, a periodic leaching regime takes place in East Siberian chernozems. The biological cycle is suppressed by low temperatures. As a result, the humus content in Transbaikal chernozems is low (4-9%) and the thickness of the humus horizon is small. There is very little or no carbonate content. Therefore, the chernozems of the East Siberian group are called low-carbonate and non-carbonate (for example, leached chernozems of low-carbonate or non-carbonate, ordinary chernozems of low-carbonate).[...]
Most minor elements, at concentrations common in many natural ecosystems, have little effect on organisms, perhaps because the organisms have adapted to them. Thus, the migrations of these elements were of little interest to us if by-products of the mining industry, various industries, the chemical industry and modern agriculture, products containing high concentrations of heavy metals, toxic organic compounds and other potentially hazardous substances did not too often enter the environment . Even a very rare element, if it is introduced into the environment in the form of a highly toxic metal compound or radioactive isotope, can acquire important biological significance, since even a small (from a geochemical point of view) amount of such a substance can have a pronounced biological effect.[...]
The chemical nature of vitamins and other growth-stimulating organic compounds, as well as the need for them in humans and domestic animals, has long been known; however, research into these substances at the ecosystem level has only just begun. Organic nutrients in water or soil are so low that they should be called "micro-micronutrients" as opposed to "macronutrients" such as nitrogen and "micronutrients" such as trace metals (see Chapter 5). Often the only way to measure their content is a biological test: special strains of microorganisms are used, the growth rate of which is proportional to the concentration of organic nutrients. As emphasized in the previous section, the role of a substance and its flow rate cannot always be judged by its concentration. It is now becoming clear that organic nutrients play an important role in community metabolism and that they may be a limiting factor. This interesting area of research will undoubtedly attract the attention of scientists in the near future. The following description of the vitamin B12 (cobalamin) cycle, taken from Provasoli (1963), shows how little we know about organic nutrient cycling.[...]
W.R. Williams (1863-1939) developed the doctrine of agricultural factors. According to the first law of agriculture, none of the factors of plant life can be replaced by another. And, in addition, all factors of plant life are, of course, equally significant (second law). Let us highlight his important idea that soil is the result of the interaction of a small - biological and a large - geological cycle of matter.[...]
V. R. Williams closely connected his ideas in the field of genetic soil science and the study of soil fertility with practical issues of agriculture and laid them as the basis for the grass-based farming system. The most important and original views were expressed by V. R. Williams on the role of living organisms in soil formation, on the essence of the soil-forming process and the nature of individual specific processes, on the small biological cycle of substances, on soil fertility, soil humus and soil structure.[...]
These approaches are essentially related as strategy and tactics, as a choice of long-term behavior and measures of priority decisions. They cannot be separated: pollution of the human environment harms other organisms and living nature in general, and the degradation of natural systems weakens their ability to naturally cleanse the environment. But it should always be understood that it is impossible to preserve the quality of the human environment without the participation of natural ecological mechanisms. Even if we master low-polluting technologies, we will achieve nothing unless we simultaneously stop preventing nature from regulating the composition of the environment, purifying it and making it suitable for life. The cleanest technologies and the most advanced environmental protection devices will not save us if deforestation continues, the diversity of biological species decreases, and the cycle of substances in nature is disrupted. It should be emphasized that from an environmental point of view, the concept of “protection” is flawed from the very beginning, since activities should be structured in such a way as not to allow, to prevent all effects and results from which they would then have to be “protected”.[...]
About 99% of all matter in the biosphere is transformed by living organisms, and the total biomass of the Earth's living matter is estimated at only 2.4 1012 tons of dry matter, which is 10"9 part of the Earth's mass. Annual biomass reproduction is about 170 billion tons of dry matter. The total biomass of plant organisms is 2500 times greater than that of animals, but the species diversity of the zoosphere is 6 times richer than that of the phytosphere. If all living organisms were laid out in one layer, then a biological cover only 5 mm thick would form on the surface of the Earth. But despite the small size of the biota, it is it that determines the local conditions on the surface of the earth’s crust. Its existence is responsible for the appearance of free oxygen in the atmosphere, the formation of soils and the cycle of elements in nature.[...]
We have already described mushrooms above, and we actually call its fruiting body a mushroom, but this is only a part of a huge organism. This is an extensive network of microscopic fibers (reefs), which is called mycelium (mycelium) and permeates detritus, mainly wood, leaf litter, etc. As the mycelium grows, it secretes a significant number of enzymes that decompose the wood to a state ready for consumption, and Gradually, the mycelium completely decomposes dead wood. It is interesting, as B. Nebel writes (1993), that it is possible to find mushrooms on inorganic soil, since their mycelium is capable of extracting even very low concentrations of organic substances from its thickness. Bacteria function in a similar way, but at the microscopic level. Very important for maintaining the stability of the biological cycle is the ability of fungi and some bacteria to form huge quantities of spores (reproductive cells). These microscopic particles are transported by air currents in the atmosphere over very significant distances, which allows them to spread everywhere and produce viable offspring in any space in the presence of optimal living conditions.
Large cycle of substances in nature is caused by the interaction of solar energy with the deep energy of the Earth and carries out the redistribution of matter between the biosphere and the deeper horizons of the Earth.
Sedimentary rocks, formed due to the weathering of igneous rocks, in mobile zones of the earth's crust are again immersed in a zone of high temperatures and pressures. There they melt and form magma - the source of new igneous rocks. After these rocks rise to the earth's surface and undergo weathering processes, they are again transformed into new sedimentary rocks. The new cycle does not exactly repeat the old one, but introduces something new, which over time leads to very significant changes.
Driving force great (geological) cycle 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 of external dynamics) occur 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. rel. geological activity of the atmosphere, hydrosphere, as well as living organisms and humans.
The largest forms of relief (continents and ocean basins) and large forms (mountains and plains) were formed due to endogenous processes, and medium and small forms of relief (river valleys, hills, ravines, dunes, etc.), superimposed on larger forms - due to account of exogenous processes. Thus, endogenous and exogenous processes are opposite. The former lead to the formation of large relief forms, the latter to their smoothing.
Examples of the geological cycle. Igneous rocks are transformed into sedimentary rocks as a result of weathering. In moving zones of the earth's crust, they plunge deep into 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 water cycle between land and ocean through the atmosphere (Fig. 2.1).
Rice. 2.1. The generally accepted hydrological (climatic) scheme
water cycle in nature
Moisture evaporated from the surface of the World Ocean (which consumes almost half of the solar energy reaching the Earth's surface) is transferred to land, where it falls in the form of precipitation, which 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 the natural conditions on our planet. Taking into account the transpiration of water by plants and its absorption in the biogeochemical cycle, the entire water supply on Earth breaks down and is restored in 2 million years.
Thus, the geological cycle of substances occurs without the participation of living organisms and redistributes substances between the biosphere and the deeper layers of the Earth.
Page 1
Geological cycle (large cycle of substances in nature) is a cycle of substances, the driving force of which is exogenous and endogenous geological processes.
Geological cycle is the circulation of substances, the driving force of which is exogenous and endogenous geological processes.
The boundaries of the geological cycle are much wider than the boundaries of the biosphere; its amplitude covers layers of the earth's crust far beyond the boundaries of the biosphere. And, most importantly, living organisms play a secondary role in the processes of this cycle.
Thus, the geological cycle of substances occurs without the participation of living organisms and redistributes substances between the biosphere and the deeper layers of the Earth.
The most important role in the large cycle of the geological cycle is played by small cycles of matter, both biosphere and technospheric, once in which the matter is switched off for a long time from the large geochemical flow, transforming in endless cycles of synthesis and decomposition.
The most important role in the large cycle of the geological cycle is played by small cycles of matter, both biosphere and technospheric, once in which the matter is switched off for a long time from the large geochemical flow, transforming in endless cycles of synthesis and decomposition.
This carbon takes part in the slow geological cycle.
It is this carbon that takes part in the slow geological cycle. Life on Earth and the gas balance of the atmosphere are supported by relatively small amounts of carbon contained in plant (5 10 t) and animal (5 109 t) tissues participating in the small (biogenic) cycle. However, at present, humans are intensively closing the cycle of substances, including carbon. For example, it is estimated that the total biomass of all domestic animals already exceeds the biomass of all wild terrestrial animals. The areas of cultivated plants are approaching the areas of natural biogeocenoses, and many cultural ecosystems are significantly superior to natural ones in their productivity, continuously increased by humans.
The most extensive in time and space is the so-called geological cycle of substances.
There are 2 types of circulation of substances in nature: large or geological cycle of substances between land and ocean; small or biological - between soil and plants.
Water extracted by a plant from the soil enters the atmosphere in a vapor state, then, cooling, condenses and returns to the soil or ocean in the form of precipitation. The geological water cycle provides mechanical redistribution, deposition, accumulation of solid sediments on land and at the bottom of reservoirs, as well as in the process of mechanical destruction of soils and rocks. However, the chemical function of water is carried out with the participation of living organisms or their metabolic products. Natural waters, like soils, are complex bioinert substances.
Human geochemical activity is becoming comparable in scale to biological and geological processes. In the geological cycle, the denudation link increases sharply.
The factor that leaves the main imprint on the general character and biological. At the same time, the geological water cycle continuously strives to wash all these elements from the layers of crumbling land into the ocean basin. Therefore, the preservation of plant food elements within the land requires their conversion into a form that is absolutely insoluble in water. This requirement is met by living organic matter.
Before the emergence of the biosphere, there were three cycles of matter on Earth: mineral cycle - movement of igneous products from the depths to the surface and back; gas cycle - circulation of air masses periodically heated by the Sun,The water cycle - evaporation of water and its transfer by air masses, precipitation (rain, snow). These three cycles are united by a single term - geological (abiotic) cycle. With the advent of life, the gas, mineral and water cycles were supplemented by biotic (biogenic) cycle - the cycle of chemical elements carried out by the vital activity of organisms. Together with the geological one, a single biogeochemical cycle substances on Earth.
Geological cycle.
About half of the solar energy reaching the Earth's surface is spent on the evaporation of water, weathering of rocks, dissolution of minerals, movement of air masses and, with them, water vapor, dust, and solid weathering particles.
The movement of water and wind leads to soil erosion, movement, redistribution and accumulation of mechanical and chemical precipitation in the hydrosphere and lithosphere. This cycle is still happening today.
Of great interest The water cycle. Approximately 3.8 10 14 tons of water evaporate from the hydrosphere in one year, and only 3.4 10 14 tons of water returns with precipitation to the water shell of the Earth. The missing part falls onto land. In total, about 1 10 14 tons of precipitation falls on land, and approximately 0.6 10 14 tons of water evaporate. Excess water formed in the lithosphere flows into lakes and rivers, and then into the World Ocean (Fig. 2.4). Surface runoff is approximately 0.2 10 14 tons, the remaining 0.2 10 14 tons of water enters subsoil aquifers, from where water flows into rivers, lakes and the ocean, and also replenishes groundwater reservoirs.
biotic cycle. It is based on the processes of synthesis of organic substances with their subsequent destruction into the original minerals. The processes of synthesis and destruction of organic substances are the foundation of the existence of living matter and the main feature of the functioning of the biosphere.
The life activity of any organism is impossible without metabolism with the environment. In the process of metabolism, the body consumes and assimilates necessary substances and releases waste products; the size of our planet is not infinite, and ultimately all useful substances would be processed into useless waste. However, in the process of evolution, an excellent solution was found: in addition to organisms that can build living matter from non-living matter, other organisms appeared that decomposed this complex organic matter into initial minerals, ready for new use. “The only way to give a limited quantity the properties of infinity,” wrote V.R. Williams, is to make it rotate along a closed curve."
The mechanism of interaction between living and inanimate nature consists of the involvement of inanimate matter in the realm of life. After a series of transformations of inanimate matter in living organisms, it returns to its previous original state. Such a cycle is possible due to the fact that living organisms contain the same chemical elements as inanimate nature.
How does this cycle happen? V.I. Vernadsky substantiated that the main converter of energy coming from space (mainly solar) is the green matter of plants. Only they are capable of synthesizing primary organic compounds under the influence of solar energy. The scientist calculated that the total surface area of the green matter of plants that absorbs energy, depending on the time of year, ranges from 0.86 to 4.2% of the surface area of the Sun. At the same time, the surface area of the Earth
Animals whose food is plants or other animals synthesize new organic compounds in their bodies.
The remains of animals and plants serve as food for worms, fungi and microorganisms, which ultimately convert them into the original minerals, releasing carbon dioxide. These minerals again serve as the initial raw materials for the creation of primary organic compounds by plants. Thus the circle closes and a new movement of atoms begins.
However, the cycle of substances is not completely closed. Some of the atoms come out of the cycle, are fixed and organized by new forms of living organisms and the products of their vital activity. Penetrating into the lithosphere, hydrosphere and troposphere, living organisms have produced and are producing enormous geochemical work on the movement and redistribution of existing substances and the creation of new ones. This is the essence of the progressive development of the biosphere, since this expands the scope of biogeochemical cycles and strengthens the biosphere. As V.I. Vernadsky noted, in the biosphere there is a constant biogenic movement of atoms in the form of “vortices”.
Unlike the geological one, the biotic cycle is characterized by insignificant energy consumption. As already noted, about 1% of solar energy reaching the Earth's surface is spent on the creation of primary organic matter. This energy is sufficient for the functioning of the most complex biogeochemical processes on the planet.
Page 1
The Great Geological Cycle draws sedimentary rocks deep into the earth's crust, permanently excluding the elements they contain from the biological circulation system. In the course of geological history, 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 biosphere cycle.
The Great Geological Cycle occurs over hundreds of thousands or millions of years. It is as follows: rocks are subject to destruction, weathering and are ultimately washed away by streams of water into the World Ocean. Here they are deposited on the bottom, forming sediment, and only partially return to land with organisms removed from the water by humans or other animals.
The basis of the 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 cycle, there is a large, geological cycle. Some substances enter the deep layers of the Earth (through sea bottom sediments or other means), 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, the large cycle of substances is closed. It takes millions of years.
Concerning the speed and intensity of the large geological cycle of substances, it is currently impossible to provide 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.
This carbon takes part in the large geological cycle. This carbon, in the process of the small biotic cycle, maintains the gas balance of the biosphere and life in general.
| Solid runoff from some rivers of the world. |
The contribution of biosphere and technosphere components to the large geological cycle of the Earth's substances is very significant: there is a constantly progressive growth of technosphere components due to the expansion of the scope of human production activity.
Since on the earth's surface the main techno-geochemical flow is directed within the framework of a large geological cycle 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, the differentiation of the substance 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 as a whole.
The circulation of water between land and ocean through the atmosphere is part of the great geological cycle. Water evaporates from the surface of the oceans and is either transported to land, where it falls as precipitation, which returns to the ocean in the form of surface and underground runoff, or falls as precipitation on the surface of the ocean. More than 500 thousand km3 of water annually participates in the water cycle on Earth. 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 water supply on Earth breaks down 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 transfer of matter by surface and underground waters is the main factor in the differentiation of the earth's land in geochemical terms, but not the only one, and if we talk about the large geological circulation of substances on the earth's surface in general, then flows play a very significant role in it, in particular oceanic and atmospheric transport.
Concerning the speed and intensity of the large geological cycle of substances, it is currently impossible to provide any accurate 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 cycle of substances is a constantly ongoing process of denudation of the earth's surface.