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Ostroumov S. A. Basics of the molecular-ecological mechanism of water quality formation and water self-purification. - Contemporary Problems of Ecology, 2008 (Feb), Vol. 1, No. 1, p. 147-152. [ISSN 1995-4255 (Print) 1995-4263 (Online); DOI 10.1134/S1995425508010177; https://www.researchgate.net/file.FileLoader.html?key=e533be77c87735c6dcc5cfdb9db96cec; http://www.springerlink.com/content/e380263154u73045/; http://scipeople.ru/users/2943391/; Original Russian Text: published in Sibirskii Ekologicheskii Zhurnal, 2006, Vol. 13, No. 6, pp. 699–706]. The paper formulates some basics of the modern ecological theory of the polyfunctional role of biota in the molecular-ecological mechanism of water quality formation and self-purification of aquatic ecosystems. The theory covers the following items: (1) sources of energy for self-purification mechanisms, (2) the main structural and functional units of the self-purification system, (3) the main processes involved in the system, (4) contributions of major taxa to self-purification, (5) self-purification system reliability and supporting mechanisms, (6) the response of some components of the self-purification system to external factors, (7) particulars of the operation of water purification mechanisms, and (8) conclusions and recommendations for biodiversity preservation practice. Surfactants, detergents, salts of Cd, Cu, Pb, Hg, Co, Ti, V (Na3VO4 •12 H2O), and oil hydrocarbons inhibited water filtration by bivalves, mussels Mytilus galloprovincialis. DOI: 10.1134/S1995425508010177 From the text of the paper: A set of six principles was formulated. These principles are typically predominant but not universal because some ecosystems demonstrate deviations from them. 1. Moderation of the rate of water self-purification by regulatory mechanisms. The actual rate of certain processes is in many cases lower than the maximal expected one. This may be related to the action of regulatory mechanisms. It has been noted that if the maximum value of a parameter in an ecosystem does not match its optimum value for organisms, this parameter is likely to undergo self-regulation [19]. For example, the rate of water filtration by aquatic organisms is regulated. It decreases significantly at elevated suspension concentration in water in comparison with the maximum possible rate. 2. Typically, maximal diversification of the executives of the main functions of water quality formation and self-purification machinery is observed. Indeed, as mentioned above, virtually all functions (oxygen release, DOM oxidation and conversion, water filtration, etc.) are duplicated, being performed by multiple species of the ecosystem. 3. Multiple stages of the biogenic migration of elements in the operation of the molecular ecological mechanism of water medium parameter formation are often observed. For example, the carbon atom of a carbon dioxide molecule is involved in a pathway of many stages: It is reduced during photosynthesis by an alga; then it is oxidized in the body of a heterotroph consumer, or it comes to bottom sediments with debris, where it can be oxidized by an aerobic bacterium; then it is reduced again by a methanogenic bacterium to form methane; then it is oxidized by a methanotrophic bacterium; and eventually, this carbon can again be involved in photosynthesis. 4. Synecological cooperation: Many processes participating in the formation of water medium parameter formation and self-purification occur at higher rates and efficiencies owing to cooperation of two or more aquatic species. 5. The significance of biota is constantly preserved at a high level throughout the ecosystem volume and all the time, independently of the time of day, season, and succession stage. 6. Regulated balance of oppositely directed processes. Organisms simultaneously excrete and absorb organic molecules, oxygen, and carbon dioxide; produce suspended organic matter (SOM) and remove it from water by filtration; etc. This fact points once more to the importance of all regulation types, involving biotic and abiotic factors, and emphasizes the danger of anthropogenic distortion of these regulatory mechanisms. In some respects (continuous operation, importance for maintaining the structure and stability of biologic systems, and pollutant sensitivity), the molecular ecological mechanism of water quality formation and maintenance and restoration of water medium parameters in aquatic ecosystems is similar to reparation mechanisms at other life organization levels. This article concerns only some components of the complex set of processes and factors involved in water medium parameter formation and water self-purification. Other components of the self-purification machinery are considered in [3, 5, 15, 16, 19]. 8. Conclusions and recommendations for environment preservation practice. On the grounds of our experimental studies [8–13], other publications of mine [14], and data published by other scientists [e.g., 3, 4], the following conclusions can be drawn: 1. Virtually all species are involved in processes responsible for aquatic ecosystem self-purification or in regulation of these processes. Distortion of these regulatory mechanisms manifests itself most clearly after invasion of new species into the ecosystems. This provides another argument for the preservation of the whole biodiversity in aquatic ecosystems [14]. 2. Species of terrestrial ecosystems and habitats adjacent to water basins and watercourses take an active part in purification processes. Therefore, water quality preservation demands the preservation of the biodiversity of these terrestrial ecosystems as well. 3. The modern concept of biodiversity preservation differs from the previous one, based on the preservation of species gene pool. It follows from the analysis reported in [13, 14] that the biodiversity-preservation tasks and conditions should include not only preservation of gene pools and populations but also preservation of the functional activity of these populations, which contributes to the maintenance of water quality and, as a consequence, the maintenance of stability of the whole aquatic ecosystem. 4. The operation of self-purification machinery in an ecosystem should be taken into account to determine critical anthropogenic loads [15] on the ecosystem and to evaluate the threat of anthropogenic impact on biota [20–22]. 5. The self-purification system is important for analyzing the role and fate of most important pollutants, including radionuclides [16], heavy metals [23–25], and other pollutants. 6. The theory under development emphasizes the importance of molecular conversion of pollutants. The poor understanding of this problem is related to blanks in the knowledge of aquatic ecosystems. The filling of these blanks should be given priority to in further studies. They include problems of biochemistry and biophysics of aquatic ecosystems [19, 26]; better knowledge of the biochemical composition of DOM, role and metabolism of particular DOM classes; and determination of concentrations and activities of the enzymes dissolved in waters of natural water bodies (exoenzymes), as well as of the enzymes immobilized on interfaces in aquatic ecosystems. Comprehensive analysis of self-purification mechanisms demands a broad range of factual data and consideration of additional sources in scientific literature. More detailed bibliography on the issues considered here is presented in [27–29]. Table 1. Some factors and processes involved in the molecular ecological mechanism of water quality formation as compiled from studies by many scientists No. Water purification factors and processes 1 PHYSICAL AND PHYSICOCHEMICAL 1.1 Dissolution and dilution 1.2 Carryover to the banks 1.3 Carryover to adjacent water basins and watercourses 1.4 Adsorption by suspended particles followed by sedimentation 1.5 Adsorption by bottom sediments 1.6 Evaporation 2 CHEMICAL 2.1 Hydrolysis 2.2 Photochemical conversion of DOM and pollutants 2.3 Catalytic redox conversion 2.4 Pollutant conversion induced by free radicals 2.5 Decrease in pollutant toxicity owing to binding to DOM 2.6 Oxygen-mediated chemical oxidation of pollutants 3 BIOTIC 3.1 Adsorption and accumulation of pollutants, DOM, and biogens by aquatic organisms 3.2 Pollutant bioconversion: redox reactions, degradation, and conjugation 3.3 Extracellular enzymatic conversion of pollutant and DOM molecules performed by enzymes dissolved in the water of natural basins and watercourses (exoenzymes) and enzymes immobilized on interfaces in aquatic ecosystems 3.4 Removal of suspended particles from the water column by water filtration by aquatic organisms 3.5 Removal of suspended particles from the water column by adsorption on pellets excreted by aquatic organisms 3.6 Arrest or retardation of the supply of biogens and pollutants from bottom sediments to the water column; accumulation and binding of biogens and pollutants by benthic organisms 3.7 Carryover of C, N, and P from the ecosystem with aquatic insect imagos (Plecoptera, Ephemeroptera, Odonata, Trichoptera, Diptera, etc.) 3.8 Production of allelopathic and bactericidal substances and their excretion to water 3.9 Carryover of C, N, and P from the ecosystem in the course of nourishment of fish-feeding and other predatory animals living in areas adjacent to the water basin 3.10 Carryover of C, N, and P from the ecosystem with amphibians leaving water for land in the course of metamorphosis 3.11 Release of hydrogen peroxide by algae, which is essential for pollutant conversion by redox reactions 3.12 Excretion of substances participating in photochemical degradation of chemicals and pollutants (photosensibilizers and their precursors) 3.13 Excretion of substances essential for free-radical-mediated degradation of chemicals (organic ligands and their precursors) 3.14 Excretion of organic substances participating in formation of an organic surface film regulating heat and matter transport between the water and atmosphere (for details, see [19]) 3.15 Bioconversion and adsorption of pollutants in soil during field watering with polluted water 3.16 Further fragmentation of large organism fragments supplied to the basin by aquatic animals 3.17 Regulation of the population and activity of organisms involved in water purification by interactions between organisms Table 2. Recent data on the disturbance of water filtration as part of its self-purification under the action of pollutants. Action of various pollutants on the removal of suspended matter from water by filter-feeding organisms. The degree of suppressing activity of chemicals (effect on the efficiency of suspension removal, EESR) was calculated as in [6] REFERENCES 1. L. M. Sushcheva, Quantitative Parameters of Crustacean Nutrition (Nauka i Tekhnika, Minsk, 1975). 2. A. F. Alimov, Principles of the Theory of Aquatic Ecosystem Functioning (Nauka, St. Petersburg, 2000). 3. A. V. Monakov, Nutrition of Freshwater Invertebrates (Institute of Ecology and Evolution, Moscow, 1998) . 4. R. G. Wetzel, Limnology: Lake and River Ecosystems (Academic Press, San Diego, 2001). 5. Yu. A. Izrael and A. V. Tsyban’, Anthropogenic Ecology of the Ocean (Gidrometeoizdat, Leningrad, 1989). 6. S. A. Ostroumov, Biological Effects of the Action of Surfactants on Organisms (MAKS-Press, Moscow, 2001) . 7. S. A. 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