Natural water is exactly the environment where numerous microorganisms intensively reproduce, and therefore the microflora of water will never cease to be the object of close attention of man. How intensively they multiply depends on many factors. In natural water, mineral and organic substances are always dissolved in one or another amount, which serve as a kind of "food", thanks to which the entire microflora of water exists. In terms of quantity and quality, the composition of micro-inhabitants is very diverse. It is almost never possible to say that this or that water, in this or that source, is pure.
Artesian water
Key or artesian waters are underground, but this does not mean at all that microorganisms are absent in them. They are sure to exist, and their composition depends on the nature of the soil, soil and the depth of this aquifer. The deeper - the poorer the microflora of water, but this does not mean that it is completely absent.
The most significant amount of bacteria is found in ordinary wells that are not deep enough to seep into themsurface contamination. It is there that pathogenic microorganisms are most often found. And the higher the groundwater is, the richer and more abundant the microflora of the water. Almost all closed-type reservoirs are excessively saline, since s alt has accumulated underground for many hundreds of years. Therefore, most often artesian water is filtered before drinking.
Surface waters
Open reservoirs, that is, surface waters - rivers, lakes, reservoirs, ponds, swamps, and so on - have a variable chemical composition, and therefore the composition of the microflora there is very diverse. This is because every drop of water is contaminated with household and often industrial waste, and the remains of rotting algae. Rain streams flow here, bringing a variety of microlife from the soil, and sewage from factory and factory production also enters here.
Simultaneously with all kinds of mineral and organic pollution, water bodies also receive huge masses of microorganisms, including pathogenic ones. Even for technological purposes, water is used that meets GOST 2874-82 (in one milliliter of such water there should not be more than a hundred cells of bacteria, in a liter - no more than three cells of Escherichia coli.
Pathogenic agents
Such water under a microscope presents the researcher with a number of causative agents of intestinal infections, which remain virulent for quite a long time. For example, in ordinary tap water, the causative agent of dysentery is viable for up to twenty-seven days, typhoid fever - up toninety-three days, cholera - up to twenty-eight. And in river water - three or four times longer! Typhoid fever threatens the disease one hundred and eighty-three days!
The pathogenic microflora of water is carefully monitored, and if necessary, even quarantine is declared - in case of a threat of an outbreak of the disease. Even sub-zero temperatures do not kill most microorganisms. A frozen drop of water stores quite viable typhoid bacteria for several weeks, and this can be verified using a microscope.
Quantity
The number of microbes and their composition in open water directly depend on the chemical reactions taking place there. The microflora of drinking water greatly increases with the dense population of coastal areas. At different times of the year, it changes its composition, and there are many other reasons for changes in one direction or another. The cleanest reservoirs contain up to eighty percent of coccal bacteria among all microflora. The remaining twenty are for the most part rod-shaped bacteria without spores.
Near industrial enterprises or large settlements in a cubic centimeter of river water, there are many hundreds of thousands and millions of bacteria. Where there is almost no civilization - in taiga and mountain rivers - water under a microscope shows only hundreds or thousands of bacteria in the same drop. In stagnant water, there are naturally many more microorganisms, especially near the banks, as well as in the upper layer of water and in the silt at the bottom. Silt is a nursery for bacteria, from which a kind of film is formed, due to which most of the processes of transformation of substances of the entire reservoir occurand the microflora of natural waters is formed. After heavy rains and spring floods, the number of bacteria also increases in all water bodies.
"Blossoming" of the reservoir
If aquatic organisms begin to massively develop, it can cause quite significant harm. Microscopic algae multiply rapidly, which causes the process of the so-called flowering of the reservoir. Even if such a phenomenon is small in scale, the organoleptic properties deteriorate sharply, even filters at waterworks can fail, the composition of the water microflora does not allow it to be considered drinking water.
Particularly harmful in mass development are some types of blue-green algae: it causes many irreparable troubles from loss of livestock and fish poisoning to serious human diseases. Along with the "blooming" of water, conditions are created for the development of various microorganisms - protozoa, fungi, viruses. Together, all this is microbial plankton. Since water microflora plays a special role in human life, microbiology is one of the most important areas of science.
Water environment and its types
The qualitative composition of the microflora depends directly on the origin of the water itself, on the habitat of microscopic organisms. There are fresh waters, surface waters - rivers, streams, lakes, ponds, reservoirs, which have a characteristic composition of microflora. In underground, as already mentioned, depending on the depth of occurrence, the number and composition of microorganisms changes. There are atmospheric waters - rain, snow, ice,which also contain certain microorganisms. There are s alt lakes and seas, where, accordingly, the microflora characteristic of such an environment is located.
Also, water can be distinguished by the nature of use - it is drinking water (local water supply or centralized, which is taken from underground sources or from open reservoirs. Swimming pool water, household, food and medical ice. Waste water requires special attention from the sanitary side They are also classified: industrial, domestic fecal, mixed (the two types listed above), storm and melt. Wastewater microflora always pollutes natural water.
Character of microflora
The microflora of water bodies is divided into two groups depending on the given aquatic environment. These are their own - autochthonous aquatic organisms and allochthonous, that is, they enter when polluted from the outside. Autochthonous microorganisms constantly living and multiplying in the water resemble the microflora of the soil, coastal or bottom, with which the water comes into contact. Specific aquatic microflora almost always contains Proteus Leptospira, its various species, Micrococcus candicans M. roseus, Pseudomonas fluorescens, Bacterium aquatilis com mum's, Sarcina lutea. Anaerobes in not too polluted water bodies are represented by Clostridium, Chromobacterium violaceum, B. mycoides, Bacillus cereus.
Allochthonous microflora is characterized by the presence of a combination of microorganisms that remain active for a relatively short time. But there are more tenaciouspolluting water for a long time and threatening human and animal he alth. These are the causative agents of subcutaneous mycoses Clostridium tetani, Bacillus anthracis, some species of Clostridium, microorganisms that cause anaerobic infections - Shigella, Salmonella, Pseudomonas, Leptospira, Mycobacterium, Franciselfa, Brucella, Vibrio, as well as pangolin virus and enteroviruses. Their number varies quite widely, since it depends on the type of reservoir, the season, meteorological conditions and the degree of pollution.
Positive and negative value of microflora
The cycle of substances in nature is significantly dependent on the vital activity of microorganisms in water. They break down organic matter of plant and animal origin, provide food for everything living in the water. Pollution of water bodies is most often not chemical, but biological.
The waters of all surface reservoirs are open to microbial contamination, that is, pollution. Those microorganisms that enter the reservoir along with sewage, melt, storm water can dramatically change the sanitary regime of the area, since the microbial biocenosis itself changes. These are the main pathways for microbial contamination of surface waters.
Composition of wastewater microflora
The microflora of sewage contains the same inhabitants as in the intestines of humans and animals. It includes representatives of both normal and pathogenic flora - tularemia, pathogens of intestinal infections, leptospirosis, yersiniosis, hepatitis viruses, poliomyelitis and many others. Swimming inbody of water, some people infect the water, while others become infected. It also happens when rinsing clothes, when bathing animals.
Even in the pool, where the water is chlorinated and purified, BGKP bacteria are found - a group of Escherichia coli, staphylococci, enterococci, Neisseria, spore-forming and pigment-forming bacteria, various fungi and microorganisms such as viruses and protozoa. Bacteria carriers bathing there leave behind shigella and salmonella. Since water is not a very favorable environment for reproduction, pathogenic microorganisms take the slightest opportunity to find their main biotope - an animal or human body.
Not so bad
Reservoirs, like the great and mighty Russian language, are capable of self-purification. The main way is competition, when the saprotic microflora is activated, decomposing organic matter and reducing the number of bacteria (especially successfully - of fecal origin). The permanent species of microorganisms included in this biocenosis are actively fighting for their place under the sun, leaving not an inch of their space to the aliens.
The most important thing here is the qualitative and quantitative ratio of microbes. It is extremely unstable, and the impact of various factors greatly affects the state of the water. Saprobicity is important here - a complex of features that a particular reservoir possesses, that is, the number of microorganisms and their composition, the concentration of organic and inorganic substances. Usually self-purification of the reservoir occurs sequentiallyand is never interrupted, whereby biocenoses are gradually replaced. Pollution of surface waters is distinguished in three gradations. These are oligosaprobic, mesosaprobic and polysaprobic zones.
Zones
Zones of particularly severe pollution - polysaprobic - almost without oxygen, since it is taken by a huge amount of easily decomposing organic matter. The microbial biocenosis is accordingly very large, but limited in species composition: mainly anaerobic bacteria, fungi and actinomycetes live there. One milliliter of this water contains over a million bacteria.
The zone of moderate pollution - mesosaprobic - is characterized by the dominance of nitrication and oxidative processes. The composition of bacteria is more diverse: obligately aerobic, nitrifying bacteria are the majority, but with the presence of species of Candida, Streptomyces, Flavobacterium, Mycobacterium, Pseudomonas, Clostridium and others. In one milliliter of this water, there are no longer millions, but some hundreds of thousands of microorganisms.
The zone of pure water is called oligosaprobic and is characterized by a self-cleaning process that has already ended. There is a small content of organic matter and the mineralization process is completed. The purity of this water is high: there are no more than a thousand microorganisms in a milliliter. All pathogenic bacteria have already lost their viability there.
