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

Sedimentary rocks formed by the weathering of igneous rocks in mobile zones earth's crust plunge back into the zone high temperatures and pressure. 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 mineral formation, crystallization rocks and others (for example, tectonic movements, earthquakes, magmatism, metamorphism).

Exogenous processes(processes of external dynamics) proceed 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 ocean trenches) and large forms (mountains and plains) were formed due to endogenous processes, and medium and small landforms ( river valleys, hills, ravines, dunes, etc.), superimposed on larger forms - due to exogenous processes. Thus, endogenous and exogenous processes are opposite. The first leads to education large forms relief, second 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 big cycle the water cycle between land and ocean through the atmosphere can also serve (Fig. 2.1).

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

water cycle in nature

Moisture evaporated from the surface of the oceans (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 cycle of substances proceeds without the participation of living organisms and redistributes matter between the biosphere and more deep layers Earth.

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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. biological cycle. During 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 various connections, mineral and organic. The processes of geological circulation are supported mainly internal energy 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, it is currently impossible to give any accurate data, there are only approximate estimates, and then only for the exogenous component 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.

Solid runoff of some rivers of the world.

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.

Because on earth's surface the main technobio-geochemical flow 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 levels, as a result of the action gravitational forces Correspondingly, the material of the earth's crust is also differentiated from high to low elevations, from land to the 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 as 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 it is very essential role flows also play, 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.

All substances on the planet are in the process of circulation. Solar energy causes two cycles of matter on Earth: large (geological, biospheric) and small (biological).

The large circulation of substances in the biosphere is characterized by two important points: it is carried out throughout geological development Earth and is a modern planetary process that takes a leading part in the further development of the biosphere.

The geological cycle is associated with the formation and destruction of rocks and the subsequent movement of destruction products - clastic material and chemical elements. A significant role in these processes has played and continues to play thermal properties land and water surfaces: absorption and reflection sun rays, thermal conductivity and heat capacity. 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. With the formation of the biosphere, the products of vital activity of organisms were included in the great cycle. The geological cycle supplies living organisms with nutrients and largely determines the conditions for their existence.

Main chemical elements lithospheres: oxygen, silicon, aluminum, iron, magnesium, sodium, potassium and others - participate in a large circulation, passing from the deep parts of the upper mantle to the surface of the lithosphere. igneous rock, which arose during crystallization

Magma, having entered the surface of the lithosphere from the depths of the Earth, undergoes decomposition and weathering in the biosphere. Weathering products pass into a mobile state, are carried by waters and wind to low relief places, fall into rivers, the ocean and form thick strata of sedimentary rocks, which, over time, sinking to depth in areas with elevated temperature and pressure, undergo metamorphosis, i.e., "remelt". During this remelting, a new metamorphic rock appears, entering the upper horizons of the earth's crust and re-entering the circulation of substances. (Fig. 32).

Rice. 32. Geological (large) circulation of substances

Easily mobile substances - gases and natural waters that make up the planet's atmosphere and hydrosphere. The material of the lithosphere cycles much more slowly. In general, each circulation of any chemical element is part of the general large circulation of substances on Earth, and all of them are closely interconnected. Living matter biosphere in this cycle does a great job of redistributing chemical elements that are continuously circulating in the biosphere, moving from external environment into organisms and back into the environment.

Small, or biological, circulation of substances- This

circulation of substances between plants, animals, fungi, microorganisms and soil. The essence of the biological cycle is the flow of two opposite, but interrelated processes - the creation of organic substances and their destruction. First stage the emergence of organic substances is due to the photosynthesis of green plants, i.e. the formation of living matter from carbon dioxide, water and simple mineral compounds using solar energy. Plants (producers) extract molecules of sulfur, phosphorus, calcium, potassium, magnesium, manganese, silicon, aluminum, zinc, copper and other elements from the soil in a solution. Herbivorous animals (consumers of the first order) absorb compounds of these elements already in the form of food plant origin. Predators (consumers of the second order) feed on herbivorous animals, consuming more than complex composition, including proteins, fats, amino acids and other substances. In the process of destruction by microorganisms (decomposers) of organic substances of dead plants and animal remains, into the soil and aquatic environment simple mineral compounds available for assimilation by plants enter, and the next round of the biological cycle begins (Fig. 33).

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 cycle 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 of sunlight, thermal conductivity into 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. The transference also speaks of its geological manifestation. air masses weathering products, and 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 further development biosphere (Radkevich, 1983).

On the present stage development of mankind, 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 ground 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, which 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 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.