The biogeochemical circulation of substances in the biosphere is the most important natural process of the continuous exchange of various elements between inanimate environment and organisms (animals, plants, etc.). Their fundamental characteristics are the basis of everything. The most important include the ability to metabolism, reproduction, and the transfer of hereditary properties.
Biogeochemical nitrogen cycle
Each element has its own meaning. An important role in the composition of various organic compounds is played by nitrogen. Despite the high percentage of nitrogen in the atmosphere, it is inaccessible to plants and animals. There are reasons for this. Energetically, plants are more profitable to use mineral nitrogen, and animals - as part of organic compounds.
Molecular nitrogen from the atmosphere binds nitrogen-fixing microorganisms and contribute to its accumulation in the soil in the form of ammonia. Others use nitrogen from dead organisms. They also contribute to the accumulation of ammonia. It turns into nitrates, actively used by plants. These are, in general terms, the features of the biogeochemical nitrogen cycle. Consider also the process of exchange of other natural substances.
Features of the biogeochemical cycle of carbon, sulfur and phosphorus
These chemical elements are necessary for every living organism. However, their living needs are not limited to this. Therefore, macrocells are involved in a small biological cycle (the need for organisms in them is quite large): potassium, magnesium, sodium; as well as trace elements: boron, manganese, chlorine, etc.
They enter plants from the soil, although often with atmospheric precipitation. As part of the phytomass, carbon, sulfur, and phosphorus are consumed by herbivorous consumers and thus enter the trophic chains. However, some animals satisfy the need for these elements, bypassing plants. Ungulates visit salt licks, gnawing soil, or eat excrement, old bones. Sea animals absorb salts directly from the water. In the process of mineralization of dead residues, microorganisms return chemical elements to soil and water. Thus, their activity contributes to the enrichment of the environment with nutrients.
Ecosystem balance
In the small biogeochemical cycle in the biosphere, its completeness is an important circumstance. In the ecosystem, the income and consumption of elements are balanced, while the difficulties arise mainly with elements that are reserved in the soil.
The balance of the flow of substances and energy determines the stability of the ecosystem - its homeostasis. The biosphere uses external sources of energy, which ensures its orderliness and a rather complex structure. The scattered light energy by plants is transferred to a concentrated state of the energy of chemical bonds.
At the same time, both the removal of energy from the environment and its transformation does not lead to waste generation.
The impact of human activities on biosphere processes
Human intervention in biogeochemical cycles is carried out in various ways. First of all, this is the destruction of the biocomponent of the ecosystem (destruction of plants or changes in the territory during the extraction of energy carriers). When burning organic matter, the energy from the concentrated state passes into the dispersed state, which leads to thermal pollution with aerosols and gaseous products of combustion. In the natural ecosystem, atoms participating in biogeochemical cycles are reused. This is facilitated by the participation in the cycles of light biogenic elements that make up the vital substance.
Human intervention entails introducing into the environment not only an additional amount of its inherent elements, but also new chemical compounds, including those synthesized by humans. Many of them are absorbed by plants and then enter the food chain.
An example is lead, compounds of mercury, arsenic, etc. The intake of such substances disrupts the natural cycle, changing the balance of elements, or leads to their accumulation in living organisms, reducing their productivity or causing death. Pesticides and heavy metals have a particularly severe destructive effect. Thus, the sustainability of the ecosystem, its homeostaticity can be violated directly or indirectly by human activities.
Ecological pyramid
Let us turn to the most important regularities of the functioning of the ecosystem and biogeochemical cycles. We will use the principle of the ecological pyramid for this. It is based on the biological mass of trophic equations. The area of any part of such a pyramid is approximately equal to the mass of the substance. Since organisms build their level using the previous one, this area should gradually be reduced. Such a decrease in each level can be tenfold.
For example, the ecological pyramid characteristic of terrestrial ecosystems, in which producers are perennials, has a large biomass, although the production process is not of the highest intensity. It is balanced by the annual increase in the mass of herbivorous animals. The pattern of formation of organic matter is called the rule of the pyramid. There are other varieties of it.
Inverted pyramid
Take the ecosystem of water bodies. The pyramid built for them may look a little different. She looks upside down. The fact is that short-lived algae reproduce very quickly, but are just as intensively consumed by consumers. Therefore, the biomass simultaneously taken into account in this case does not reflect the intensity of the production process in the favorable period of the year. If we take into account that large consumers (fish, crustaceans) accumulate and eat more slowly, the total mass of consumers is higher.
The production process in the ecosystem enables their successful functioning. It determines the nature of the energy flow in the biosphere. As you know, living organisms are its consumers. Light energy coming from the sun is used by green plants and leads to the formation of organic molecules, where it is stored in the form of chemical bonds. Part of it is released during the respiration of plants and is used by them for the growth, absorption and movement of substances. So the biogeochemical cycle is carried out.
Energy exchange
As you know, there are laws of thermodynamics. Part of the energy is lost, giving off heat. This is the effect of one of the laws. He argues that energy loss is obligatory in the process of its transformation from one species to another. When accumulated in plant matter, it is used by animals.
The breakdown of molecules is accompanied by the release of energy. A significant part of it is used in the process of animal life, passing from one form to another. These are the processes of biosynthesis and energy storage of new bonds. This is mechanical, electrical, thermal and other types of energy. When it is converted, a part is again lost, giving off heat. Energy is gradually moving to another level. Moreover, its loss also occurs when some of the undigested food (excrement) is thrown away and in organic metabolic waste (excreta).
Energy use process
Chaos is rare in nature, usually everything is ordered. Let us pay attention to some quantitative laws of the process of using and converting energy. At the first stage, plants use an average of about 1% of its income. Sometimes this figure reaches 2%. In the least favorable conditions, it decreases to 0.1%. In the transition of energy from producers to consumers of the first order, the efficiency reaches 10%.
Carnivores, as we see, more effectively absorb food. This is due to the peculiarities of the chemical composition of food and the ease of its digestion by animals. Nevertheless, already at the level of third-level consumers, the amount of incoming energy is very small and is characterized by thousandths of the initial values.