published as: 
Ostroumov S.A. Polyfunctional role of biodiversity in processes leading to water purification: current conceptualizations and concluding remarks.- Hydrobiologia, 2002, 469: 203-204.

POLYFUNCTIONAL ROLE OF BIODIVERSITY IN PROCESSES LEADING TO WATER PURIFICATION: CURRENT CONCEPTUALIZATIONS AND CONCLUDING REMARKS

S.A.Ostroumov     
(Faculty of Biology, Moscow State University, Moscow 119234; saostro[at]online.ru)

Key words: water quality, water purification, self-purification, biodiversity, pollutants, ecosystem services, freshwater, marine, aquatic ecosystems, sustainability

Sustainable use of aquatic resources is based on the ability of aquatic ecosystems to maintain a certain level of water quality. Water self-purification in both freshwater and marine ecosystems is based on a number of interconnected  processes (e.g., Wetzel, 1983; Spellman, 1996; Ostroumov 1998, 2000). Among them are:
(1) physical and physico-chemical processes, including: (1.1) solution and dilution of pollutants; (1.2) export of pollutants to the adjacent land areas; (1.3) export of pollutants to the adjacent water bodies; (1.4) sorption of pollutants onto suspended particles and further sedimentation of the latter; (1.5) sorption of pollutants by sediments; (1.6) evaporation of pollutants; 
(2) chemical processes, including: (2.1) hydrolysis of pollutants; (2.2) photochemical transformations;  (2.3) redox-catalytic transformations; (2.4)  transformations including free radicals; (2.5) binding of pollutants by dissolved organic matter,  which may lead to decreasing toxicity; (2.6) chemical oxidation of pollutants by oxygen; 
(3) biological processes, including:  (3.1) sorption, uptake and accumulation of pollutants by organisms; (3.2) biotransformations (redox reactions,  degradation, conjugation), mineralization of organic matter; (3.3) transformation of pollutants by extracellular enzymes; (3.4) removal of suspended matter and pollutants from the water column in the process of water filtering by filter-feeders; (3.5) removal of pollutants from the water in the process of sorption by pellets excreted by aquatic organisms; (3.6) uptake of nutrients (including P, N, and organic molecules) by organisms; (3.7) biotransformation and sorption of pollutants in soil (and removal of nutrients), important when polluted waters are in contact with terrestrial ecosystems; (3.8) a network of regulatory processes when certain organisms control or influence other organisms involved in water purification.
Living organisms are involved in physical, physico-chemical and chemical processes 1.1-1.6  and 2.1-2.6  directly or through excretion of oxygen or organic metabolites, production of suspended matter, affecting turbidity, temperature of water or other parameters of the ecosystem. As a result, living organisms are the core component of the multitude of processes of the ecological machinery working towards improving water quality. This component performs eight vital functions directly (3.1-3.8) and is involved indirectly in some of the other twelve functions (1.1-1.6  and 2.1-2.6) so that its role is clearly polyfunctional.
Living organisms of aquatic bodies (both autotrophs and heterotrophs) are enormously diverse in terms of taxonomy. Among them, autotrophs generate oxygen that is involved in the processes 2.6 and 2.4 above. Heterotrophs perform  processes 3.1, 3.2, 3.4, 3.5 and some others. Virtually all biodiversity is involved.
Given this polyfunctional role of aquatic organisms, in one of our publications we compared aquatic ecosystems to 'large-scale diversified bioreactors with a function of water purification' (Ostroumov, 2000).
What is interesting about the biomachinery of water purification is the fact that it is an energy-saving device. It is using the energy of the sun (autotrophs) and the energy of organic matter which is being oxidized in the process of being removed from water by heterotrophs.
Some interesting examples of how various organisms are incorporated in that polyfunctional activity were given by authors of the preceding papers in this volume.
The importance of aquatic organisms in performing key functions in the hydrosphere provides an additional  convincing rationale for protecting biodiversity.
The efficiency of the entire complex of those processes leading to water purification in ecosystems is a prerequisite for the sustainable use of aquatic resources. Man-made effects on any of those processes (we have shown effects of surfactants on water filtration by bivalves; some of the experiments were carried out together with Dr. P. Donkin) may impair the efficiency of water self-purification (Ostroumov, 1998; Ostroumov et al., 1998; Ostroumov & Fedorov, 1999; Ostroumov  2001a, 2001b). 
We postulate and predict that further studies will provide new striking examples of how important biodiversity is in performing many vital ecological processes leading to upgrading water quality. By doing so, the multifunctional participation of biodiversity supports the sustainable use of water as one of key resources for mankind.
The  body of new data and  ideas presented in this volume will hopefully serve towards following interconnected and partially overlapping goals:
prioritization of efforts on research and management in the area of aquatic resources and aquatic environment;
biodiversity studies and protection;
sustainable use of aquatic bioresources;
advancement of aquaculture and mariculture;
decreasing costs and increasing efficiencies in wastewater treatment using ecosystems;
combatting eutrophication; 
understanding the role of biota in biogeochemical flows of chemical elements and in buffering global change.
Acknowledgement. The author thanks   Acad. Prof. A. F. Alimov, Acad.Prof. D. S. Pavlov, Acad. Prof. M. E. Vinogradov, Prof. C. Steinberg, Prof. N. Walz, Prof. P. Wangersky for discussions, the Open Society Foundation for support.
REFERENCES
Ostroumov, S.A., 1998. Biological filtering and ecological machinery for self-purification and bioremediation in aquatic ecosystems: towards a holistic view.  Rivista di Biologia / Biology Forum. 91: 247-258.
Ostroumov, S.A., 2000. Aquatic ecosystem: a large-scale, diversified bioreactor with the function of water self-purification (Vodnaja ekosistema: krupnorazmernyj diversifitzirovannyj bioreaktor s funktzijej samoochishchenija vody). Doklady Biological Sciences 374: 514-516 (the Russian edition: Dokl. Akad. Nauk 374: 427-429). http://www.ncbi.nlm.nih.gov/pubmed/11103331; http://sites.google.com/site/2000dbs374p514bioreactor/
Ostroumov, S.A., 2001a. Amphiphilic chemical inhibits the ability of molluscs to filter water and to remove the cells of phytoplankton (Amfifil'noe veshchestvo podavljaet sposobnost' molluskov filtrovat' vodu i udalat' iz nee kletki fitoplanktona). Izvestia RAN. Ser. Biology. 1: 108-116. Translated into English: An amphiphilic substance inhibits the mollusk capacity to filter out phytoplankton cells from water. - Biology Bulletin, 2001, Vol. 28, No. 1, p. 95-102. DOI 10.1023/A:1026671024000. PMID: 11236572 [PubMed - indexed for MEDLINE].
Ostroumov, S.A., 2001b. Effects of amphiphilic chemicals on marine organisms filter-feeders (Vozdeistvie amfifil'nykh veshchestv na morskikh gidrobiontov-filtratorov). Dokl. Akad. Nauk . Vol.  378. No. 2: 283-285. Translated into English: Effect of amphiphilic chemicals on filter-feeding marine organisms. -  Doklady Biological Sciences. 2001. 378: 248-250. http://sites.google.com/site/2001dbs378p248effammaroyst/; DOI 10.1023/A:1019270825775.
Ostroumov, S.A., P. Donkin & F. Staff, 1998. Filtration inhibition induced by two classes of synthetic surfactants in the bivalve mollusc (Narushenije filtratzii dvustvorchatymi molluskami pod vozdejstvijem poverkhnostno-aktivnykh veshchestv dvukh klassov). Dokl. Akad. Nauk  362: 574-576. Translated into English: Filtration inhibition induced by two classes of synthetic surfactants in the bivalve mollusk Mytilus edulis // Doklady Biological Sciences, 1998. Vol. 362, P. 454-456.
Ostroumov, S.A. & V.D. Fedorov, 1999. The main components  of self-purification of ecosystems and its possible impairment as a result of chemical pollution (Osnovnyje komponenty samoochishchenija ekosistem i vozmozhnost' ego narushenija v rezultate khimicheskogo zagrjaznenija). Bulletin of Moscow University. Ser. 16. Biology (Vestnik Moskovskogo Universiteta. Ser. 16. Biologija) 1: 24-32.
Spellman, F.R., 1996. Stream Ecology and Self-purification. Technomic Publishing Co.,  Lancaster, Basel. 133 pp.
Wetzel, R. G., 1983. Limnology. Saunders College Publishing, Fort Worth. 858 pp.

ADDENDUM
(added when the paper was put at the web site).
The main conclusions of the paper were supported in a series of publications. The following publications are among them.
1.	Ostroumov S. A. Biological Effects of Surfactants. CRC Press. Taylor & Francis. Boca Raton, London, New York. 2006. 279 p. ISBN 0-8493-2526-9.
2.	Ostroumov S. A. The concept of aquatic biota as a labile  and vulnerable component of the water self-purification system - Doklady Biological Sciences, Vol. 372, 2000, pp. 286–289. http://sites.google.com/site/2000dbs372p286biotalabil/;
3.	Ostroumov S. A.,  Kolesnikov M. P. Biocatalysis of Matter Transfer in a Microcosm Is Inhibited by a Contaminant: Effects of a Surfactant on Limnea stagnalis. - Doklady Biological Sciences, 2000,  373: 397–399. Translated from Doklady Akademii Nauk, 2000, Vol. 373, No. 2, pp. 278–280. http://sites.google.com/site/2000dbs373p397biocatallstag/
4.	Ostroumov S. A. An aquatic ecosystem: a large-scale diversified bioreactor with a water self-purification function. - Doklady Biological Sciences, 2000. Vol. 374, P. 514-516.  http://sites.google.com/site/2000dbs374p514bioreactor/ 
5.	Ostroumov SA. Criteria of ecological hazards due to anthropogenic effects on the biota: searching for a system. - Dokl Biol Sci (Doklady Biological Sciences). 2000; 371:204-206. http://sites.google.com/site/2000dbs371p204criteria/ 
6.	Ostroumov S. A. An amphiphilic substance inhibits the mollusk capacity to filter out phytoplankton cells from water. - Biology Bulletin, 2001, Volume 28, Number 1, p. 95-102.
ISSN	1062-3590 (Print) 1608-3059 (Online); DOI	10.1023/A:1026671024000; http://www.springerlink.com/content/l665628020163255/;
7.	Ostroumov S. A. Inhibitory Analysis of Regulatory Interactions in Trophic Webs. -Doklady Biological Sciences, 2001, Vol. 377, pp. 139–141. Translated from Doklady Akademii Nauk, 2000, Vol. 375, No. 6, pp. 847–849. http://sites.google.com/site/2001dbs377p139inhibitory/; 
8.	Ostroumov SA. The synecological approach to the problem of eutrophication. - Dokl Biol Sci. (Doklady Biological Sciences). 2001; 381:559-562. http://scipeople.com/uploads/materials/4389/Danbio6_2001v381n5.E.eutrophication.pdf 
9.	Ostroumov SA. The hazard of a two-level synergism of synecological summation of anthropogenic effects. - Dokl Biol Sci. (Doklady Biological Sciences).  2001; 380:499-501. http://sites.google.com/site/2001dbs380p499synerg/  
10.	Ostroumov SA. Responses of Unio tumidus to mixed chemical preparations and the hazard of synecological summation of anthropogenic effects.  - Dokl Biol Sci (Doklady Biological Sciences). 2001; 380: 492-495. http://sites.google.com/site/2001dbs380p492unio/
11.	Ostroumov SA, Kolesnikov MP. Pellets of some mollusks in the biogeochemical flows of C, N, P, Si, and Al. - Dokl Biol Sci (Doklady Biological Sciences). 2001; 379:378-381. http://sites.google.com/site/2001dbs379p378pellets/
12.	Ostroumov SA. Imbalance of factors providing control of unicellular plankton populations exposed to anthropogenic impact. - Dokl Biol Sci (Doklady Biological Sciences). 2001; 379:341-343. http://sites.google.com/site/1dbs379p341imbalance/; 
13.	 Ostroumov SA. Effect of amphiphilic chemicals on filter-feeding marine organisms.-  Dokl Biol Sci (Doklady Biological Sciences). 2001; 378:248-250. http://sites.google.com/site/2001dbs378p248effammaroyst/
14.	Ostroumov SA. Biodiversity protection and quality of water: the role of feedbacks in ecosystems. -  Dokl Biol Sci (Doklady Biological Sciences). 2002; 382:18-21; http://sites.google.com/site/2dbs382p18biodivers/; http://www.citeulike.org/pdf/user/ATP/article/6113559/ostroumov_02_biodiversity.pdf;
15.	Ostroumov SA.  A new type of effect of potentially hazardous substances: uncouplers of pelagial-benthal coupling. - Dokl Biol Sci (Doklady Biological Sciences). 2002; 383:127-130. https://www.researchgate.net/file.FileLoader.html?key=d988acb599e121964c48114374a87e8d; www.springerlink.com/index/28V23JBFADL1Y100.pdf; 
16.	Ostroumov S. A. Identification of a New Type of Ecological Hazard of Chemicals: Inhibition of Processes of Ecological Remediation. - Doklady Biological Sciences, Vol. 385, 2002 (November), pp. 377–379. [Translated from Doklady Akademii Nauk, Vol. 385, No. 4, 2002, pp. 571–573]. https://www.researchgate.net/file.FileLoader.html?key=8408a7cfaa984764b812ce79c77007f2;
17.	Ostroumov SA. System of principles for conservation of the biogeocenotic function and the biodiversity of filter-feeders. - Dokl Biol Sci (Doklady Biological Sciences). 2002; 383:147-150. https://www.researchgate.net/file.FileLoader.html?key=888352078b275ef40a430eb5b4d7714c;  
18.	Ostroumov S. A., Walz N., Rusche R. Effect of a cationic amphiphilic compound on rotifers. - Doklady Biological Sciences. 2003 (May). Vol. 390. 252-255, [ISSN 0012-4966 (Print) 1608-3105 (Online)]. https://www.researchgate.net/file.FileLoader.html?key=def6575c794b111fcc31275e853c2b15;
19.	Ostroumov S.A. Anthropogenic effects on the biota: towards a new system of principles and criteria for analysis of ecological hazards. - Rivista di Biologia/Biology Forum. 2003.  96: 159-170.  PMID: 12852181 [PubMed - indexed for MEDLINE] http://sites.google.com/site/ostroumovsergei/publications-1/rivista2003criteria; http://scipeople.com/uploads/materials/4389/3RB96p159Anth..Criteria.doc; www.ncbi.nlm.nih.gov/pubmed/12852181;
20.	Ostroumov S. A. On the biotic self-purification of aquatic ecosystems: elements of the theory. - Doklady Biological Sciences, 2004, Vol. 396, Numbers 1-6, p. 206-211. https://www.researchgate.net/file.FileLoader.html?key=60f338228d6f3c5114d223ab81e15d3b;  
21.	Ostroumov S. A.,  Widdows J.  Inhibition of mussel suspension feeding by surfactants of  three classes. // Hydrobiologia. 2006. Vol. 556, No. 1. Pages: 381 – 386. DOI 10.1007/s10750-005-1200-7; http://sites.google.com/site/ostroumovsergei/publications-1/hydrobiologia2006ostwidd; http://sites.google.com/site/3surfactantsfiltrationmytilus/; http://scipeople.ru/uploads/materials/4389/_Hydrobiologia2006%20vol%20556%20No.1%20pages381-386.pdf; http://www.springerlink.com/content/7166067538534421/
22.	Ostroumov S. A. Biotic self-purification of aquatic ecosystems: from the theory to ecotechnologies. - Ecologica, 2007. vol. 15 (50), p.15-23. (ISSN 0354-3285). [http://scindeks.nb.rs/article.aspx?artid=0354-32850750015O].
23.	Ostroumov S.A., Shestakova T.V. Decreasing the measurable concentrations of Cu, Zn, Cd, and Pb in the water of the experimental systems containing Ceratophyllum demersum: The phytoremediation potential // Doklady Biological Sciences 2009, Vol. 428, No. 1, p. 444-447. http://sites.google.com/site/9dbs444/; https://www.researchgate.net/file.FileLoader.html?key=8fd8998627b86102db72c9b237c25054;
24.	Ostroumov S.A. Towards  the general theory of ecosystem-depended control of water quality. - Ecologica, 2009, vol. 16, No. 54, p. 25-32. http://sites.google.com/site/9enecologica16p25theory/
25.	Ostroumov S. A. Basics of the molecular-ecological mechanism of water quality formation and water self-purification.- Contemporary Problems of Ecology, 2008, Vol. 1, No. 1, p. 147-152. [MAIK Nauka/Interperiodica; distributed by Springer Science+Business Media LLC; ISSN 1995-4255 (Print) 1995-4263 (Online);  DOI 10.1134/S1995425508010177;   

The paper was cited in the publications written by scientists and experts working in several countries. Among those publications are:

Hydrobiologia, 2006, 556: 365-379, DOI 10.1007/s10750-004-0189-7; 
Journal of Applied Phycology, 2005, 17: 557-567, DOI 10.1007/s10811-005-9006-6; Mediterranean Marine Science, 2007, Volume 8 (2), 19-32; 
Aquatic Ecosystem Health & Management, 2009,  Volume 12, Number 2, pp. 215-225, DOI: 10.1080/14634980902908589; 
Desalination, 2010, Vol. 250, Issue 1, Pages 118-129, DOI:10.1016/j.desal.2008.12.062.