What is the biotic cycle? As a closed system, it has been successfully functioning for several billion years.
Let's try to figure out what the biotic cycle is.
Features
Dead plants and remains of organisms are processed by insects, fungi, bacteria, and protozoa. Animals and plants are gradually transformed into elemental 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 closure, continuity, decay, decomposition of final compounds. It is a continuous circle that governs life on the planet.
Significance
The biotic cycle of carbon in terrestrial ecosystems will be considered using the example of phosphorus. A sufficient amount of this element is found in the humus horizons of undisturbed soils, as well as in the forest litter. Thanks to the cycle, it is possible to accumulate about 106-107 tons of phosphorus in the biosphere. The phytomass of natural meadow steppes contains about 30 kg/ha of this element, which is quite enough for mammals.
Energy Exchange
The biotic cycle involves energy exchange. Its essence boils down to the fact that energy does not disappear in the chain of food (trophic) transformations, but its transformation from one type to another is observed.
Solar energy is transformed through a similar process at every level. Direct consumption of solar energy is typical only for green plants in the framework of photosynthesis.
They create an organic compound (glucose) from carbon dioxide and water, and energy is accumulated. Leaves of plants are included in this chemical process only in the presence of sunlight and chlorophyll.
Process Features
In some periods of the existence of mankind, the biotic cycle of substances was disturbed. Only surpluses were withdrawn, which were deposited as gas, coal, oil, limestone, and other organic minerals.
During the combustion of oil or coal in furnaces (motors), energy is released and used, which has been accumulated by the biosphere over millions of years. In the past, such surplusesdid not litter the biosphere, their negative impact on the biotic cycle was not observed. Today is different.
Specifics
Diversity of animals is important for the successful implementation of the cycle. One species will not be able to break down the organic substances of plants in the biogeocenosis to the final products. It breaks down only a part of them, as well as some of the organic compounds that are in them. Networks and food chains are formed in a similar way.
In the biocenosis, the atmosphere is important. It helps to maintain the biological cycle of energy and substances, as well as to ensure water balance.
Pollutant can decompose into forms that can be involved in subsequent stages of the cycle and assimilated by living organisms.
The cycle is based on the decomposition and absorption of pollutants by microorganisms, it depends on the activity and quantity of chemical elements directly involved in the cycle.
An ecosystem is the sum of inorganic and organic components within which the biotic cycle of substances takes place.
Process Diagram
Plants, receiving a constant flow of energy from the Sun, form primary products from inorganic matter. In the remaining links of the cycle, there is a change and loss of energy. Producers, consumers, decomposers in the ecosystem consume the living matter of the original production. Animals consume for such a process many times more living matter of the lowest level, lowering the totalenergy reserves. Circulation is provided through the interaction of the three groups.
The first group consists of producers. These include green plants that are actively involved in photosynthesis. Such substances are also 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. These include predators, as well as protozoa. Animals that are classified as predators, about 250 different species.
The third group - destructors (decomposers), which decompose dead organic matter to minerals. These include fungi, bacteria, and protozoa. The accumulation of solar energy is carried out 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 does biology consider? Plant respiration occupies an important place in it, since this process oxidizes almost half of the organic matter to carbon dioxide, returning it to the atmosphere.
The second largest variant of spending organic compounds and stored energy is the use of first-order consumers of plants. The energy that is stored by phytophages with food is spent on vital activity, respiration, and reproduction. She is excreted in excrement.
Herbivorous animals are food for carnivores (consumers of the highest trophic level). They, in turn, waste energy,accumulated with food, similar to herbivorous animals.
Relationship of elements
A separate link in the ecosystem supplies organic residues to the environment. They serve as a source of energy and food for saprophage 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 re-enter the atmosphere and soil, being food for plants.
The biotic cycle is a continuous process of creating and breaking down organic compounds. It is realized through all three groups of organisms. Life without producers is impossible, since they are the basis of life. Only they have the ability to create primary organic matter, without which the subsequent cycle will not proceed.
Due to the consumption of consumers of different orders of primary and secondary production, transfer from one species to another, a variety of forms is possible on Earth. Reducers that decompose organics return it to the first stage of the cycle.
Large-scale cycles of migration of chemical components bind the outer shells of the planet into one whole, they explain the continuity of evolution.
The energy of the Sun acts as the driving force of the biotic cycle. The main process contributing to the production of organic matter is photosynthesis. It is possible only when green plants use solar energy.
Leaves of plants (autotrophs),which synthesize glucose, “conserve” solar energy into an organic compound. Getting into the biosphere from space, energy accumulates in plants, rocks, and soil. The sun provides the cycle of chemical elements, allows you to form alternately inorganic or organic substances.
What is important to know
In addition to carbon, oxygen, hydrogen, other biologically important elements also take part in the biotic cycle: calcium, nitrogen, phosphorus, silicon, potassium, sodium, sulfur. This process is also impossible without trace elements: iodine, zinc, bromine, molybdenum, silver, nickel, lead, magnesium. In the list of elements that are absorbed by living matter, there are even poisons - arsenic, selenium, mercury, as well as radioactive components (radium, uranium).
Cycling speed
Energy exchange is cyclical. The renewal of the living matter of the biosphere is carried out 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. Complete replacement of water in the hydrosphere takes 2800 years.
Chemical compounds that are available for the components of the biosphere are limited. Due to their exhaustibility, the development of some groups of organisms in the ocean and on land is inhibited.
Circulation options
Only thanks to the circulation of energy and substances, a stable state of the biosphere is maintained. There are two options - geological (large) and biogeochemical (small).
Consider the firstcycle option. Igneous rocks under the influence of biological, chemical, physical factors turn into sedimentary rocks, in particular, into clay and sand. They can also arise 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 there is their transformation, the processes of metamorphism are observed. Under the action of portions of endogenous energy, the layers are remelted, forming magma. When they rise to the surface of the Earth under the influence of weathering, transfer, they are again transformed into sedimentary rocks.
The great cycle is characterized by the interaction of exogenous (solar) energy with the endogenous (deep) energy of the Earth. Thanks to this process, the substance 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 (seas, lakes, rivers), then returns to the earth in the form of precipitation. Compensate for such processes river runoff. Vegetation plays an important role in the water cycle.
Small circulation is typical only for the biosphere. Cycles are created on a planetary scale from cyclic multiple movements of atoms, as well as those movements that are caused by volcanism, the movement of the seabed, wind energy, underground flows.
Summarize
In the biosphere substances circulate,forming biogeochemical cycles. They need the following elements in large quantities: 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 the global closure of the cycle operates. The basis of such a process is solar energy, as well as the chlorophyll of green plants.
For the complete decomposition of organic matter, which is created by green plants, you need as much oxygen as is released during photosynthesis. Thanks to the burial of organic matter in peat, coal, sedimentary rocks, the exchange fund of oxygen is maintained in the atmosphere.
As a result of the increase in the number of transport, industrial enterprises, the oxygen cycle in nature is disturbed. This negatively affects the viability of the biosystem, leads to mutations and the complete extinction of some species of living plants and animals.
