Biosphere: the boundaries of the biosphere. Composition and boundaries of the biosphere. Upper limit of the biosphere

Inhabited by living organisms, which in the course of their life activity actively transform it.

History of study

The concept of the biosphere as an area of ​​life was introduced into science by Jean-Baptiste de Lamarck in the first half of the 19th century. It was he who came closest to understanding her. But the term itself was proposed by the Austrian scientist Edward Suess. He worked in the field of geology and understood the biosphere as the totality of all organisms. Now such a meaning is embedded in the term "biota". Suess outlined 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 the Russian scientist geochemist, who has encyclopedic knowledge in many branches of science - Vladimir Ivanovich Vernadsky. As 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.

V. M. 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 has ever existed, that is, the biosphere is characterized by the presence of living organisms or their metabolic products.

Types of substances in the biosphere

VI Vernadsky singled out several types of substances that form the basis of the biosphere.

1. Actually living matter, which is formed by a combination of organisms.
2. A biogenic substance that is formed during and remains after the vital activity of organisms. We are talking about atmospheric gases, coal, oil and so on.
3. which is formed without the intervention of organisms.
4. - these 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 combination of the above substances in the Earth's shells.

Living matter in the biosphere

It is obvious that the main geochemical and energy processes proceed with the obligatory participation of V. I. Vernadsky formulated the concept of it in this way. Living matter - all that exist at the moment, constituting a single set, which is expressed in the elementary chemical composition, weight, energy.

The main property of living matter is its activity, due to the connection with the environment by a constant biogenic flow. The flow is formed during breathing, nutrition, reproduction. In this context, the vital activity of organisms can be considered as a powerful geological process of a planetary nature.

Constant migrations of chemical elements between the organism and the environment in both directions occur continuously. The implementation of this process is possible due to the proximity of the elemental chemical composition of organisms to the chemical composition of the earth's crust.

Plants, carrying out photosynthesis, create in the biosphere complex organic molecules with a large supply of energy. Thus, living matter accumulates and transforms the bound radiant energy of the Sun. The movement of energy becomes possible due to the constant growth and development of the organism. The rate of reproduction, as V. I. Vernadsky rightly believed, is the rate at which geochemical energy is transferred in the biosphere.

Borders

The part of the biosphere in which there are currently living organisms is commonly called the neobiosphere. 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 2420 billion tons. This value is 200 times the mass of the atmosphere. Thus, we can conclude that the layer of living matter in the total mass of the geospheres is negligible.

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

It should be noted that, unlike other earthly shells, only the biosphere can be considered complex. It also performs the function of a “cover” from a living entity and is the habitat of many organisms, including humans.

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 depths of the ocean, in which the pressure can reach 12,000 atmospheres - all this is the biosphere. The boundaries of the biosphere are so wide because of the very wide limits of temperature tolerance of organisms.

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

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

Upper limit of the biosphere

In different parts of the planet, life in the atmosphere exists at different altitudes. 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, the lower part of the atmosphere, is filled with life.

The physical limit of the propagation of life in the atmosphere is at the lower boundary

Hydrosphere

The hydrosphere is formed by oceans, seas, lakes, rivers and ice sheets. There is life in every depth. The vast majority of living organisms occupied the surface layers and coastal areas. But even at a depth of 11,022 m, in the deepest basin of the World Ocean (Mariinsky), there are inhabitants. The neobiosphere also includes bottom sediments that were once the habitat of ancient creatures.

Lower limit of the biosphere

If we talk about the lithosphere, then the soil is, of course, its most densely populated layer, but the existence of life has been noticed much deeper - about 6-7 kilometers underground. This concerns, first of all, deep cracks and caves.

Organisms that inhabit the biosphere

Living organisms are divided into two groups depending on the method of obtaining the 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 in their diet are not connected with any other living beings. For this they require sunlight or the energy of chemical bonds of compounds of inorganic origin. Both can be used as a source of energy, while they receive nutrition from minerals.

Autotrophs are divided into two subgroups. These are phototrophs (green) and chemotrophs (bacteria). The first are able to exist only in the area of ​​penetration of sunlight. But the latter, due to the use of chemical compounds of organic nature as an energy source, are much more widespread.

Heterotrophs, on the contrary, require organic substances produced by other organisms as sources of energy and nutrition. That is, without the preliminary work of autotrophs, their existence would be impossible. Animals and man, as a resident of the biosphere, are heterotrophic organisms.

"Films of Life"

The uneven distribution of life is one of the important features that characterizes the biosphere. The boundaries of the biosphere have the lowest density of life. The greatest is observed at the junctions of habitats. On the whole, the distribution of life in the biosphere is sharply uneven. V. I. Vernadsky introduced the term "Films of Life", describing with its help the most densely populated areas of the biosphere. The soil-air contact boundary 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), i.e., the area of ​​free penetration of the sun's ray.

Thus, life, which transforms the "face of the Earth", is inextricably 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 ensures life on Earth.