The heterotrophic process occurring in the BGC throughout the entire biogeosphere approximately balances the autotrophic accumulation of matter. During respiration, which is a process of biological oxidation, energy is released. Based on respiration, there are food chains of saprophages.
There are three forms of breathing:
aerobic respiration - oxidizer (acceptor) - oxygen;
Anaerobic respiration has two types:
When an inorganic substance serves as an oxidizing agent
When the acceptor is an organic matter.
Bacteria, yeast, molds and some protozoa carry out their metabolism with the help of anaerobic respiration. Sometimes anaerobic fermentation is a critical component of an ecosystem. For example, thanks to the activity of sulfate-reducing bacteria, there is a stable balance in the Black Sea, which is only 2000 years old. Biologically, this sea is very highly productive - the annual production volume is 1x10 14 g by dry weight, which corresponds to a productivity of about 100 g of carbon per 1 m 2 of surface per year. And since the mixing of waters in the Black Sea is very weak due to the weak intensity of currents, there is only enough oxygen for biological processes in surface waters. In the depths there is not enough of it and the existence of biological populations is impossible. Below 50 m depth, the oxygen concentration begins to decrease catastrophically and reaches a mark already at a depth of 175 m. Here the activity of sulfate-reducing bacteria begins, which decompose organic matter coming from above, releasing hydrogen sulfide and carbon dioxide. Thanks to this, the waters of the Black Sea at a depth of 200 m and below are saturated with hydrogen sulfide.
In swamp biogeocenoses, the activity of methane bacteria plays a great role, which, by reducing organic carbon or carbon contained in carbonates, destroy organic compounds with the formation of methane. Methane, or swamp gas, rises to the surface and oxidizes, sometimes igniting, forming strange luminous clouds of bizarre figures in the night air. These bacteria also exist in the stomachs of ruminants, where they decompose plant matter.
Anaerobic decomposition processes are slower than aerobic ones. However, in nature they are of great importance, because they pass in hard-to-reach places and are additional suppliers of matter and energy, making them available to anaerobes. Thus, as a result of the activity of sulfate-reducing bacteria, hydrogen sulfide and carbon dioxide enter surface waters, where they are used by phytoplankton.
Biological decomposition always occurs during feeding, gradually, since none of the saprotrophs can complete decomposition. There are three stages of biological decomposition:
1. Grinding of detritus through physical or biological action;
2. Formation of humus and release of soluble organic matter
3. Slow mineralization of humus.
This confirms nature's general strategy of eating the pie so that it always remains whole.
Stage 1 of decomposition - grinding of detritus - occurs as a result of the feeding of phytophages. This includes herbivorous vertebrate and invertebrate organisms.
A. Herbivores, consuming vegetation, convert it into fats, proteins and sugars of animal origin. These substances decompose very quickly if the animals themselves turn into corpses. So, Odum carried out an experiment by placing the corpses of crabs in plastic bags and, for control, marsh grass. In 10 months, the crabs decomposed completely, and the grass only 60%.
B. The part of food not digested by herbivores, passing through the digestive tract, is thrown out in the form of excrement. This part of the detrital organic matter becomes the property of the links in the food chain of coprophages. Among coprophagous arthropods, a distinction is made between ectocoprophages, which develop in the dung heap itself, and telecoprophagous animals, which develop outside the dung heap. These are usually beetles that make balls of dung, roll them a considerable distance and bury them in the soil. Systematically, they belong to the family Geotrupiidae and Scarabaeidae. They hatch their larvae in these buried balls of dung. Burying manure has a beneficial effect on nature - it increases soil fertility and increases the growth of pasture plants. In addition, populations of infectious flies are suppressed, which are deprived of favorable places for laying eggs and decomposes helminths in cattle.
IN. Insects are coprophages, consuming manure and passing it through their intestines, increasing the degree of its fragmentation. The excrement of coprophages is easily processed by bacterial flora, and various fungi develop well on them. The excrement environment of dung invertebrates has high phosphatase activity. Therefore, there is the expression “fecal factor of coprophages,” which is of no small importance in the development of soil microflora.
Many soil invertebrates are important in the reduction of material. In the soil fauna, two groups of invertebrates stand out: arthropods and annelids.
Soil arthropods are divided into macroarthropods and microarthropods. Macroarthropods - larger than 2 mm - woodlice, beetles, centipedes, dipterans - mainly detritivores and their predators. Microarthropods - mainly mites and springtails - are also detritivores. Many detritivores cannot digest cellulose themselves. In this case, they resort to the help of microflora. Thus, the larvae of scarab beetles reproduce bacteria in their intestines. The bacteria feed on manure and multiply, which is what the larvae feed on. On the other hand, ammonifying bacteria develop in the ball of manure, which the larvae also feed on. Many detritivores release proteins and growth substances into detritus with their excrement, which stimulate the growth of microorganisms. In turn, by destroying bacteria, they stimulate accelerated growth of the bacterial population.
Annelids are a phylum that contains 8,000 species, of which two families are particularly important in soil life: Lumbricidae and Enchytraeidae.
Lumbricidae, or true earthworms, reach numbers of up to 500 individuals. per m 2. Charles Darwin was the first to attach great importance to the role of earthworms in soil-forming processes. He presented a huge amount of material about the extent of the worms’ activity, about the fact that they pass the entire soil of a meadow through their intestines in a few years. He did not exaggerate the importance of worms at all; rather, he even underestimated them, because... he based on the number of worms per 1 hectare of meadow being 60-133 thousand individuals, while it can reach up to 2 million per hectare, and a maximum of 20 million. It is estimated that on average per year all the worms in the world throw out as much soil to the surface as than can cover the entire land with a layer of three mm.
Enchytraeids ranging in size from 2 to 45 mm reproduce in the soil in huge quantities - up to 150 thousand per 1 sq.m.
The role and significance of saprotrophic bacteria in nature
Ecological niches
Saprophytic bacteria are one of the most numerous groups of microorganisms. If we talk about the place of saprotrophs in ecological systems, they always displace heterotrophs. Heterotrophs are organisms that cannot produce organic compounds themselves, but are only engaged in processing existing material.
The group of saprotrophs includes representatives of many families and genera of bacteria:
- Pseudomonas aeruginosa (Pseudomonas);
- Escherichia coli (Proteus, Escherichia);
- Morganella;
- Klebsiella;
- Bacillus;
- Clostridia (Clostridium) and many others.
Saprotrophs inhabit all environments in which organic matter is present: multicellular organisms (plants and animals), soils, they are found in dust and in all types of bodies of water (except hot springs).
The result of the action of saprophytic organisms, obvious to humans, is the formation of rot - this is what the process of their feeding looks like. It is the rotting of organic material that is evidence that saprotrophs have taken over.
During the process of decay, nitrogen is released from organic compounds and returned to the soil. The reactions are accompanied by a characteristic hydrogen sulfide or ammonia odor. By this smell one can identify the beginning of the putrefactive decomposition process of a dead organism or its tissues.
Mineralization of organic nitrogen (ammonification) and its transformation into inorganic compounds - such a key role in nature is assigned to saprophytic organisms.
Physiological processes
Saprotrophs, as one of the most numerous groups, have in their ranks representatives with very different physiological needs:
- Anaerobes. For example, we can consider E. coli, which carries out its life processes without the participation of oxygen, although it can live in an oxygen environment.
- Aerobes are bacteria involved in the decomposition of organic matter in the presence of oxygen. Thus, putrefactive diplococci and three-membered bacteria are present in fresh meat. At the initial stage, the content of ammonia (a waste product of putrefactive microflora) in meat does not exceed 0.14%, and in already rotten meat – 2% or more.
- An example of spore-forming bacteria is Clostridia.
- Non-spore-forming bacteria are Escherichia coli and Pseudomonas aeruginosa.
Despite the diversity of physiological groups, united according to the characteristics of saprophyte, the final products of the activity of these bacteria have almost the same composition:
- cadaveric poisons (biogenic amines with a strong unpleasant cadaveric odor; as such, the toxicity of these compounds is low);
- aromatic compounds such as skatole and indole;
- hydrogen sulfide, thiols, dimethyl sulfoxide, etc.
Of all the listed decay products, the most dangerous and toxic to humans are the latter (hydrogen sulfide, thiols and dimethyl sulfoxide). They cause severe poisoning, even death.
Interaction
But as soon as the required amount of lactic acid ceases to be produced in the intestines, favorable conditions appear for the nutrition, growth and reproduction of putrefactive microflora, which immediately begins to poison a person with the products of their vital activity, which entails severe damage.
Wood rotting
The processing of dead wood and the return of the inorganic compounds of which it consisted to the soil is also carried out with the participation of saprotrophic bacteria. But if they play a key role in the decomposition of animal organic matter, then wood is mainly decomposed by fungi.
Putrefactive processes in wood are not caused by mold fungi. Infection of wood by mold fungi has little effect on the integrity of the wood fibers and the overall appearance of the wood. Damage caused to wood by mold can be easily removed.
The real enemy of wood is the destructive house fungus. This microorganism (eukaryote) turns wood into dust, unsuitable for further use. The presence of real house fungus in the tissues of the tree reduces the quality of the wood several times. Such material is no longer used to produce reliable and beautiful wood products.
Saprotrophs (both bacteria and fungi) feed on those objects that have a certain material value for humans. In fact, they spoil human health, their homes, food, clothing and crops. But nature cannot do without this very important group of the bacterial community. That is why a person needs to look for a way not how to destroy saprotrophs, but how to protect himself from the products of their vital activity.
More information
In biology, heterotrophs are organisms that receive nutrients from prepared foods. Unlike autotrophs, heterotrophs are not able to independently form organic substances from inorganic compounds.
general description
Examples of heterotrophs in biology are:
- animals from protozoa to humans;
- mushrooms;
- some bacteria.
The structure of heterotrophs suggests the possibility of breaking down complex organic substances into simpler compounds. In single-celled organisms, organic substances are broken down in lysosomes. Multicellular animals eat food with their mouths and break it down in the gastrointestinal tract with the help of enzymes. Fungi absorb substances from the external environment like plants. Organic compounds are absorbed along with water.
Kinds
According to the source of nutrition, heterotrophs are divided into two groups:
- consumers - animals that eat other organisms;
- decomposers - organisms that decompose organic remains.
According to the method of feeding (food absorption), consumers are classified as phagotrophs (holozoans). This group includes animals that eat organisms in parts. Reducers are osmotrophs and absorb organic substances from solutions. These include fungi and bacteria.
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Heterotrophs can use living and non-living organisms as food.
In this regard, the following are highlighted:
- biotrophs - feed exclusively on living creatures (herbivores and carnivores);
- saprotrophs - feed on dead plants and animals, their remains and excrement.
Biotrophs include:
Rice. 1. Biotrophs.
Saprotrophs include animals that eat corpses (hyenas, vultures, Tasmanian devils) or excrement (fly larvae), as well as fungi and bacteria that decompose organic remains.
Some living things are capable of photosynthesis, i.e. They are both autotrophs and heterotrophs at the same time. Such organisms are called mixotrophs. These include the eastern emerald elysia (mollusk), cyanobacteria, some protozoa, and insectivorous plants.
Consumers
Multicellular animals are consumers several orders of magnitude:
- first - feed on plant foods (cow, hare, most insects);
- second - feed on consumers of the first order (wolf, owl, human);
- third - eat third-order consumers, etc. (snake, hawk).
One organism can simultaneously be a consumer of the first and second or second and third order. For example, hedgehogs mainly eat insects, but will not refuse snakes and berries, i.e. Hedgehogs are simultaneously consumers of the first, second and third order.
Rice. 2. Example of a food chain.
Decomposers
Yeasts, fungi and heterotrophic bacteria are divided according to the method of nutrition into three types:
Rice. 3. Saprophyte mushrooms.
Saprophytes play an important role in the cycle of substances and are decomposers in the food chain. Thanks to decomposers, all organic remains are destroyed and turned into humus - a nutrient medium for plants.
Viruses are neither heterotrophs nor autotrophs, because have the properties of inanimate matter. They do not require nutrients to reproduce.
What have we learned?
Heterotrophs feed on ready-made organic substances, which they obtain by eating other organisms - plants, fungi, animals. Such organisms can feed on living organisms or their remains (biotrophs and saprotrophs). Most animals are consumers who eat other organisms (plants, animals). Decomposers that decompose organic remains include fungi and bacteria.
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Organisms can survive only at the expense of the host, feeding on the tissues of a living creature or plant. The habitat is chosen inside or outside the host: foliage, fruits, dermis, internal organs, mucous membrane. Almost all types of microorganisms are dangerous to humans. Viruses threaten life, helminths poison the body with toxic secretions, fungus destroys microflora and causes necrosis. In some cases, lack of medical care leads to death.
Fact! When infected with parasites, therapeutic treatment is always required. This can be a traditional method or medicinal or surgical intervention.
Living organisms related to saprophytes
Saprophytes are bacteria and microorganisms that feed on the remains of animals and plants. Being lower beings, almost all microorganisms are safe for humans. But there are also those that can cause harm, for example, dust mites. This inhabitant lives on any surface and feeds on dust. Another example of harmful bacteria is E. coli, which causes severe pathologies when it enters a living organism. By causing an infectious disease, the bacillus can provoke pneumonia, meningitis, sepsis - diseases with a high risk of death.
Important! The habitat of protozoan species is dead carcasses of cattle and other animals. Even though organisms do not feed on living tissue, the food must still be organic in nature. Microorganisms never settle in chemicals and other substances - this environment is destructive for them. That is why preventive measures against ticks and E. coli include hand washing and wet cleaning using soap solutions.
The life cycle of organisms is not complex. In the process of symbiosis, a viable individual is formed, capable of further reproduction by spores.
Bacteria are present everywhere: in water, air, soil, in mountainous areas and even hot geysers. They can choose plants, animals and even humans as their habitat. Bacteria have a very small size and various shapes, due to which they can penetrate even the most inaccessible places and are resistant to temperatures and other unfavorable living conditions. According to the method of nutrition, they are autotrophic and heterotrophic. The latter, in turn, are divided into saporotrophs (saprophytes) and symbionts. Let's take a closer look at saprophyte bacteria.
Basic properties of saprophytes
Saprotrophs are heterotrophic organisms that use waste products, decomposition, and decay of other living organisms as nutrients. The process of food absorption occurs due to the release of a special enzyme onto the consumed product, which breaks it down.
Nutrition is the process of storing energy and nutrients. For normal existence, bacteria require a number of nutrients, such as:
- nitrogen (in the form of amino acids);
- proteins;
- carbohydrates;
- vitamins;
- nucleotides;
- peptides.
In laboratory conditions, for the propagation of saprophytes, autolysate from yeast, whey from milk, meat hydrolysates, and some plant extracts are used as nutrient media.
An indicative process of the presence of saprophytes in products is the formation of rot. The danger comes from the waste products of these microorganisms, as they are quite toxic. Saprophytes are a kind of orderlies in the environment.
The main representatives of saprophytes:
- Pseudomonas aeruginosa (Pseudomonas);
- Escherichia coli (Proteus, Escherichia);
- Morganella;
- Klebsiella;
- Bacillus;
- Clostridia (Clostridium);
- some types of mushrooms (Penicilum, etc.)
Physiological processes of saprotrophic bacteria
Among these microorganisms are:
Doctor's opinion..."- anaerobes (Escherichia coli, it can live in an oxygen-containing environment, but all life processes take place without the participation of oxygen);
- aerobes (putrefactive bacteria that use oxygen in their life processes);
- spore-forming bacteria (genus Clostridia);
- non-spore-forming microorganisms (Escherichia coli and Pseudomonas aeruginosa).
Almost the entire variety of saprophytes, as a result of their vital activity, produces various cadaveric poisons, hydrogen sulfide, and cyclic aromatic compounds (for example, indole). The most dangerous to humans are hydrogen sulfide, thiol and dimethyl sulfoxide, which can lead to severe poisoning and even death.
Saprotrophs take their part in the process of decay.
Since by their nature these species are quite difficult to distinguish, the following classification arose:
Facultative saprophytes
Role saprotrophs In human life
This type of bacteria plays a very significant role in the cycle of nature. At the same time, the objects for their nutrition are things that are, to one degree or another, important for humans.
Saprotrophs play a very important role in the processing of organic residues. Since any organism dies at the end of its life, the nutrient medium for these microorganisms will exist continuously. Saprophytes produce, in the form of products of their vital activity, many constituent substances necessary for the nutrition of other organisms (fermentation processes, transformation of sulfur, nitrogen, phosphorus compounds, etc. in nature).
Associate Professor, Candidate of Medical Sciences - Victoria Vladimirovna Dvornichenko:
