What is a biotic cycle? As a closed system, it has been successfully operating for several billion years.
Let's try to figure out what the biotic cycle is.
Features
Dead plants and the remains of organisms process insects, fungi, bacteria, protozoa. Animals and plants are gradually turning into elementary organic and mineral compounds. The biotic cycle involves the entry of these substances into the soil, their subsequent consumption by plants. The process is characterized by isolation, continuity, decay, decomposition of the final compounds. This is a continuous circle that regulates life on the planet.
Relevance
We will consider the biotic carbon cycle in terrestrial ecosystems using phosphorus as an example. A sufficient amount of this element is found in the humus horizons of undisturbed soils, as well as in forest litter. Thanks to the cycle, it is possible to accumulate about 106-107 tons of phosphorus in the biosphere. About 30 kg / ha of this element is located in the phytomass of natural meadow steppes, which is quite enough for mammals.
Energy exchange
The biotic cycle involves energy metabolism. Its essence boils down to the fact that energy does not disappear in the chain of food (trophic) transformations, but its transformation from one species to another is observed.
Solar energy is transformed in a similar process at each of its levels. The direct consumption of solar energy is characteristic only of green plants in the framework of photosynthesis.
They create an organic compound (glucose) from carbon dioxide and water, and energy is stored. Plant leaves are included in a similar chemical process only in the presence of sunlight and chlorophyll.
Process features
In some periods of the existence of mankind, the biotic circulation of substances was disturbed. Only surplus was deposited, which was deposited as gas, coal, oil, limestone, and other organic minerals.
During the burning of oil or coal in furnaces (motors), energy is released and applied, which has accumulated by the biosphere over millions of years. In the past, such surpluses did not clog the biosphere, and their negative impact on the biotic cycle was not observed. Today, everything is different.
Specificity
For a successful cycle, animal diversity is important. One species will not be able to break down organic substances of plants in a biogeocenosis to final products. It breaks down only part of them, as well as some organic compounds that are in them. In this way, networks and power circuits are formed.
In a biocenosis, the atmosphere is important. It contributes to maintaining the biological cycle of energy and substances, as well as ensuring water balance.
The pollutant can decompose into forms that can be involved in the subsequent stages of the cycle and absorbed by living organisms.
The cycle is based on the decomposition and absorption of pollutants by microorganisms, it depends on the activity and quantitative indicator of chemical elements directly involved in the cycle.
An ecosystem is the sum of inorganic and organic components, within which a biotic cycle of substances occurs.
Process diagram
Plants, receiving a constant flow of solar energy, form primary production from inorganic matter. In the remaining links of the cycle there is a change and loss of energy. Producers, consumers, reducers in the ecosystem consume living matter of the initial production. For such a process, animals consume many times more living matter of a lower level, lowering the total energy reserves. The cycle is ensured through the interaction of three groups.
The first group consists of producers. These include green plants that are actively involved in photosynthesis. Such substances are bacteria that are capable of chemosynthesis. They form the primary organic matter.
The second group - consumers of the first order. They are consumers of organic matter. Among them are predators, as well as protozoa. Animals, which are considered predators, are about 250 different species.
The third group is destructors (reducers), which decompose dead organics into minerals. They include fungi, bacteria, and also protozoa. Solar energy is accumulated on the ascending branch of the cycle due to photosynthesis. Plants at this stage synthesize organic substances from nitrogen, water, carbon dioxide.
Energy consumption
What else is biology considering? The respiration of plants in it occupies an important place, since this process oxidizes almost half of the organic matter to carbon dioxide, and returns it to the atmosphere.
The second largest option for spending organic compounds and stored energy is the consumption of plants by consumers. The energy that is stored by phytophages with food is spent on vital functions, respiration, and reproduction. It stands out with excrement.
Herbivorous animals are food for carnivores (consumers of the highest trophic level). They, in turn, spend the energy stored in food, similar to herbivorous animals.
Element relationship
A separate part of the ecosystem into the environment supplies organic residues. They serve as a source of energy and food for saprophagous animals (fungi, bacteria). The final stage of carbohydrate conversion is the process of humification, the subsequent oxidation of humus to carbon dioxide, and the mineralization of ash fragments. They then again fall into the atmosphere and into the soil, being food for plants.
The biotic cycle is a continuous process of creation and destruction of organic compounds. It is realized through all three groups of organisms. Life is impossible without producers, since they are the basis of life. Only they have the ability to create primary organic matter, without which the subsequent circulation will not occur.
Due to the consumption of consumers of different orders of primary and secondary products, the transfer from one species to another, a variety of forms are possible on Earth. Reducers, which decompose organic matter, return it to the first stage of the cycle.
Large-scale migration cycles of chemical components bind the outer shells of the planet into a single whole, they explain the continuity of evolution.
The driving force of the biotic cycle is the energy of the sun. The main process contributing to the production of organic matter is photosynthesis. It is possible only when green plants use solar energy.
The leaves of plants (autotrophs) that synthesize glucose “conserve” solar energy into an organic compound. Getting into the biosphere from space, energy accumulates in plants, and in rocks, and in the soil. The sun provides a cycle of chemical elements, allows you to form alternately inorganic or organic substances.
What is important to know
In addition to carbon, oxygen, and hydrogen, other biologically important elements also participate in the biotic cycle: calcium, nitrogen, phosphorus, silicon, potassium, sodium, and sulfur. This process is also impossible without trace elements: iodine, zinc, bromine, molybdenum, silver, nickel, lead, magnesium. The list of elements that are absorbed by living matter contains even poisons - arsenic, selenium, mercury, as well as radioactive components (radium, uranium).
Cycle Speed
Energy exchange is cyclical in nature. The renewal of the living matter of the biosphere takes place after about 8 years. The process proceeds much faster in the ocean (after 33 days). In the atmosphere, oxygen is replaced in two thousand years, and carbon monoxide in 6 years. A complete replacement of water in the hydrosphere takes place over 2800 years.
The chemical compounds that are available for the components of the biosphere are limited. Due to their exhaustion, the development of certain groups of organisms in the ocean and on land is inhibited.
Cycle Options
Only due to the cycle of energy and substances is a stable state of the biosphere maintained. There are two options - geological (large) and biogeochemical (small).
Consider the first option of the cycle. Magmatic rocks under the influence of biological, chemical, physical factors turn into sedimentary rocks, in particular, clay and sand. They can also occur during the synthesis of biogenic minerals (dead microorganisms) from the waters of the seas and oceans. Watery loose sediments gradually accumulate at the bottom of the reservoir, harden, form dense rocks.
Then comes their transformation, the processes of metamorphism are observed. Under the action of portions of endogenous energy, the layers melt, forming magma. When raised to the surface of the Earth under the influence of weathering, transport, they again transform into sedimentary rocks.
The large cycle is characterized by the interaction of exogenous (solar) energy with the endogenous (deep) energy of the Earth. Thanks to this process, matter is redistributed between the deep horizons and the biosphere of the planet.
It also includes the movement of water between the lithosphere, atmosphere, hydrosphere, accumulated by solar energy. First, water evaporates from the surface of the ocean (sea, lake, river), then in the form of precipitation it returns to the earth. River flows compensate for such processes. Vegetation plays an important role in the water cycle.
The small cycle is characteristic only of the biosphere. Cycles of the planet are created from cyclic multiple movements of atoms, as well as those movements that are caused by volcanism, the movement of the seabed, wind energy, underground drains.
To summarize
In the biosphere, substances circulate, forming biogeochemical cycles. For them in large quantities, the following elements are needed: oxygen, nitrogen, carbon, hydrogen. Their circulation is possible due to self-regulating processes in which other components of ecosystems become active participants.
At all stages of the development of the biosphere, the law of global closure of the cycle applies. The basis of this process is solar energy, as well as chlorophyll of green plants.
For the complete decomposition of organic matter, which is created by green plants, it takes as much oxygen as it is released during photosynthesis. Due to the burial of organics in peat, coal, sedimentary rocks in the atmosphere, the oxygen exchange fund is maintained.
As a result of an increase in the amount of transport, industrial enterprises disrupt the oxygen cycle in nature. This negatively affects the viability of the biosystem, leads to mutations and the complete extinction of some species of living plants and animals.