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Biosphere: the boundaries of the biosphere. Composition and boundaries of the biosphere. The upper limit of the biosphere

Biosphere is generally considered to be the shell of the Earth, populated by living organisms, which in the course of their vital activity actively transform it.

Study history

The concept of the biosphere as a field of life was introduced into science by Jean Baptiste de Lamarque in the first half of the 19th century. It was he who came closest to her understanding. But the term itself was proposed by the Austrian scientist Edward Süss. He worked in the field of geology and understood under the biosphere the totality of all organisms. Now this meaning is put in the term "biota". Suess presented his hypotheses and research results in the famous scientific work "The Face of the Earth," in which he described the geology of the Alps.

The modern concept of the biosphere was formulated by a Russian geochemist who possesses encyclopedic knowledge in many branches of science - Vladimir I. Vernadsky. Being a professor of mineralogy at Moscow University, he became the author of the great work "Biosphere", published in 1926. It was in this work that he first gave a detailed definition of this term.

VM Vernadsky rightly believed that the biosphere is a large concentric region of the Earth, which plays the role of the main geochemical force. Thus, it is a space in which life exists at the moment or existed ever, that is, the biosphere is characterized by the presence of living organisms or products of their vital activity.

Types of substances in the biosphere

VI Vernadsky distinguished several types of substances that make up the basis of the biosphere.

  1. Actually living matter, which is formed by a combination of organisms.
  2. Biogenic substance, which is formed in the course and remains after the life of organisms. These are gases of the atmosphere, coal, oil and so on.
  3. Cosmic substance, which is formed without the intervention of organisms.
  4. Biocosic substances are compounds that are the result of the vital activity of organisms in conjunction with abiogenic processes.

The boundaries of the biosphere are determined in accordance with the presence of a set of the above substances in the shells of the Earth.

Living matter in the biosphere

It is obvious that the main geochemical and energy processes take place with the obligatory participation of living matter. VI Vernadsky so formulated the concept of it. Living matter - all living organisms existing at the moment, constituting a single set, which is expressed in an elementary chemical composition, weight, energy.

The main property of a living substance is its activity, due to the connection with the environment by a constant biogenic flux. The flow is formed by breathing, feeding, reproduction. In this context, we can consider the vital activity of organisms as a powerful geological process of a planetary nature.

Constant migration of chemical elements between the body and the environment in both directions occurs continuously. The realization of this process is possible due to the proximity of the elementary chemical composition of organisms to the chemical composition of the earth's crust.

Plants, carrying out photosynthesis, create in the biosphere complex organic molecules that have a large supply of energy. Thus, the living matter accumulates and transforms the associated radiant energy of the Sun. The movement of energy becomes possible due to the constant growth and development of the body. The speed of reproduction, as VI Vernadsky rightly considered, is the rate at which geochemical energy is transferred in the biosphere.

Borders

Part of the biosphere, in which there are currently living organisms, is usually called the neo-isosphere. In other words, modern. And the space that was the habitat of ancient organisms is the paleobiosphere.

The total mass of the planet's geospheres is approximately 2,420 billion tons. This value is 200 times greater than the mass of the atmosphere. Thus, it can be concluded that the layer of living matter in the total mass of the geospheres is negligible.

The range of potential opportunities and the scale of adaptability of organisms determine the "life expectancy". Living beings gradually settled in the seas and oceans, then settled on land. According to Vernadsky, the composition and boundaries of the biosphere are changing now.

It should be noted that, unlike other terrestrial shells, only the biosphere can be considered complex. It also performs the function of "cover" from the living entity and is the habitat of many organisms, including man.

The boundaries of the biosphere are defined as follows. It includes the lower zone of the atmosphere, the upper zone of the lithosphere, and the entire hydrosphere. And the heights of the atmosphere, characterized by cold, low pressure, and the depth of the ocean, the pressure in which can reach 12,000 atmospheres, is all the biosphere. The boundaries of the biosphere are so wide due to the very wide limits of the temperature tolerance of organisms.

It should be noted that there are bacteria that can exist in a vacuum. Limits of adaptation to chemical conditions are also very wide. The reality is the existence of organisms, for example, under the constant influence of ionizing radiation. Studies show that some living things are so hardy that according to certain criteria their possibilities are even beyond the limits of the biosphere.

In addition to the main conditions listed above, the life of organisms is conditioned by the constancy of the biogenic current of atoms.

The upper limit of the biosphere

In different parts of the world, life in the atmosphere exists at different heights. In the zones of the South and North Poles this value is 8-10 km, near the equator - 17-18 km, over all other territories - 20-25 km. Thus, only the troposphere is filled with life - the lower part of the atmosphere

The physical limit of the spread of life in the atmosphere is at the lower boundary of the ozone layer.

Hydrosphere

The hydrosphere is formed by oceans, seas, lakes, rivers and ice covers. There is life in all depths. The overwhelming majority of living organisms occupied the surface layers and the coastal zone. But even at a depth of 11 022 m, in the deepest basin of the World Ocean (Mariinsky), there are inhabitants. The non-biosphere also includes bottom sediments, which were once the habitat of ancient creatures.

Lower boundary of the biosphere

Speaking about the lithosphere, the soil is certainly the most densely populated layer of it, but the existence of life is seen much deeper - about 6-7 kilometers under the earth. This applies, first of all, to deep cracks and caves.

Organisms inhabiting the biosphere

Living organisms are divided into two groups, depending on the method of obtaining energy necessary for life: autotrophic and heterotrophic. The habitat of representatives of both groups is the biosphere. The boundaries of the biosphere are determined by their distribution.

Representatives of autotrophic organisms in their diet are not associated with any other living beings. They need sunlight or the energy of chemical bonds of compounds of inorganic origin for this. Both can be used as an energy source, whereas they are derived from mineral substances.

Autotrophs are divided into two subgroups. These are phototrophs (green) and hemotrophs (bacteria). The former can exist only in the region of penetration of the sun's rays. But the latter, due to the use of chemical compounds of organic nature as a source of energy, are much more common.

Heterotrophs, in contrast, as sources of energy and nutrition require organic substances produced by other organisms. That is, without the preliminary work of autotrophs, their existence would be impossible. Animals and humans, as inhabitants of the biosphere, belong to heterotrophic organisms.

"Films of life"

Uneven distribution of life - this is one of the important features that characterizes the biosphere. The boundaries of the biosphere have the lowest density of life. The largest is observed at the junctions of habitats. In general, the distribution of life in the biosphere is sharply uneven. VI Vernadsky introduced the term "Films of life", describing with his help the most densely populated areas of the biosphere. The boundary of the contact "soil-air" is the first of such films, its thickness is from 2 to 3 cm. The second is represented by the "air-soil" contact zone-the coastal strip and the upwelling zone. The third is represented by the euphotic zone of the ocean (up to 200 m), that is, the region of free penetration of the sun's rays.

Thus, life, transforming the "face of the Earth", is inseparably linked with the concept of "biosphere". The boundaries of the biosphere are the boundaries of life.

Spatial-functional organization is a mechanism that ensures "the geological eternity of all living things". Man, as a resident of the biosphere, along with other heterotrophic organisms is a direct participant in the energy cycle that provides life on Earth.

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