http://scipeople.ru/publication/99473/; http://www.researchgate.net/profile/Sergei_Ostroumov/blog/16361_Role_of_Biota_in_Self-Purification; Ostroumov S. A. On the Multifunctional Role of the Biota in the Self-Purification of Aquatic Ecosystems. - Russian Journal of Ecology, Vol. 36, No. 6, 2005, pp. 414–420. Translated from Ekologiya, No. 6, 2005, pp. 452–459. Moscow State University, Vorob’evy gory, Moscow, 119991, Russia; Abstract. It is the first publication that formulated a detailed conceptualiztion of principles of the ecological mechanism of water self-purification based on multiple functions of the biota in freshwater and marine ecosystems. In developing this fundamental in-depth analysis and formulating a new system of fundamental principles, the results of the author’s experiments with water filtering by filter-feeders have been used. These author's results discovered that the water self-purification mechanism is vulnerable to the impact of some pollutants and, in particular, synthetic surfactants and detergents. Conclusions drawn on the basis of the theory have practical significance for biodiversity conservation and for the sustainable use of the water resources and biological resources of aquatic ecosystems. http://www.springerlink.com/content/y6370w774lk7g786/; DOI 10.1007/s11184-005-0095-x; Additional details, and relevant publications see at: http://www.researchgate.net/profile/Sergei_Ostroumov/blog/13782_Worldwideevaluationsevidenceofmerit; [Main innovations made by Dr. S.A.Ostroumov]; A related paper see: Hydrobiologia. v.469:117-129. see: http://www.researchgate.net/profile/Sergei_Ostroumov/blog/13471_Hydrobiologia_v469117-129; Hydrobiologia. 2002. vol. 469, pages 117-129. Inhibitory analysis of top-down control: new keys to studying eutrophication, algal blooms, and water self-purification Key words: functioning of ecosystems ecosystem services aquatic ecosystems, water quality, water self-purification, pollution, theory, ecological safety, biota, organisms, marine, freshwater, water filtering, surfactants, biological resources, discovery, innovations, new data, new findings, aquatic ecology new ecotechnology ecotoxicology man-made changes anthropogenic effects new conceptualization habitat sustainability ecological stability.