Abstract
Mechanisms for coexistence among micro-organisms were studied by using a species-defined microcosm, consisting of the bacterium Escherichia coli, the ciliate Tetrahymena thermophila and the alga Euglena gracilis. These organisms were chosen as representative of ecological functional groups i.e. decomposer, consumer and producer, respectively. Direct and indirect interactions among these organisms were evaluated by comparisons of their population dynamics in culture with different combinations of the three species. There was an E. coli cell density dependent predator–prey interaction between T. thermophila and E. coli which was only established when there were more than 106 cells ml−1 of E. coli. Indirect interactions were evaluated from the cultivation of each organism in media containing metabolites of the others. Metabolites from each population strongly accelerated the growth of their own populations and those of the others except for the self-toxicity effect of E. coli metabolites. These observations suggested that not only the cell–cell contact of direct interactions, but also metabolite-mediated indirect interactions supported the maintenance of the populations of each micro-organism and their coexistence. In natural ecosystems, there are many interactions and it is difficult to evaluate all those regulating community dynamics. The gnotobiotic microcosm used in this study was shown to be suitable for examining the specific, species–species microbial interactions.
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References
Baker, E. R., J. J. A. Mclaughlin, S. H. Huter, B. Deangelis, S. Feingold, O. Frank & H. Baker, 1981. Water-soluble vitamins in cells and spent culture supernatants of Poteriochromonas stipitata, Euglena gracilis and Tetrahymena thermophila. Arch. Microbiol. 129: 310–313.
Baltzis, B. C. & A. G. Fredrickson, 1984. Competition of 2 suspension-feeding protozoan populations for a growing bacterial population in continuous culture. Microb. Ecol. 10: 61–68.
Berninger, U. G., B. J. Finlay & L. P. Kuuppo, 1991. Protozoan control of bacterial abundances in freshwater. Limnol. Oceanogr. 36: 139–147.
Beyers, R. J. & H. T. Odum, 1993. Ecological Microcosms. Springer-Verlag, New York: 557 pp.
Carmichael, W. W., 1992. Cyanobacteria secondary metabolites-the cyanotoxins. J. Appl. Bact. 72: 445–449.
Daehler, C. C. & D. R. Strong, 1996. Can you bottle nature? The role of microcosms in ecological research. Ecology 77: 663–665.
Fenchel, T., 1980. Suspension feeding in ciliated protozoa: feeding rates and their ecological significance. Microbiol. Ecol. 6: 13–25.
Fuma, S., H. Takeda, K. Miyamoto, K. Yanagisawa, Y. Inoue, N. Sato, M. Hirano & Z. Kawabata, 1998. Effects of xx-rays on the populations of the steady-state ecological microcosm. Int. J. Radiat. Biol. 74: 145–150.
Gaedke, U., 1995. A comparison of whole-community and ecosystem approaches (biomass size distributions, food web analysis, network analysis, simulation models) to study the structure, function and regulation of pelagic food webs. J. Plankton Res. 17: 1273–1305.
Giesy, Jr. J. P. (ed.), 1980. Microcosms in Ecological Research. Technological Information Center, U.S. Department of Energy: 1110 pp.
Kawabata, Z., 1990. Use of microcosms to evaluate the effect of genetically engineered micro-organisms on ecosystems. Pro. Adv. Mar. Tech. Conf. Vol. 3: 41–48.
Kawabata, Z., K. Matsui, K. Okazaki, M. Nasu, N. Nakano & T. Sugai, 1995. Synthesis of a species-defined microcosm with protozoa. J. Protozool. Res. 5: 24–27.
Kawabata, Z., N. Ishii, M. Nasu & Man-Gi Min, 1998. Dissolved DNA produced through a prey-predator relationship in a speciesdefined aquatic microcosm. Hydrobiologia 385: 71–76.
Lampert, W., 1997. Zooplankton research: the contribution of limnology to general ecological paradigms. Aquat. Ecol. 31: 19–27.
Lampert, W. & U. Sommer, 1997. Limnoecology: The Ecology of Lakes and Streams. Oxford University Press, New York: 382 pp.
Leeuwangh, P., T. C. M. Brock & K. Kersting, 1994. An evaluation of four types of freshwater model ecosystem for assessing the hazard of pesticides. Hum. Exp. Toxicol. 13: 888–899.
Legendre, L. & J. Le Fevre, 1995. Microbial food webs and the export of biogenic carbon in oceans. Aquat. Microb. Ecol. 9: 69–77.
Massana, R., J. Garcia-Cantizano & C. Pedros-Alio, 1996. Components, structure and fluxes of the microbial food web in a small, stratified lake. Aquat. Microb. Ecol. 11: 279–288.
Min, M-G., Z. Kawabata, N. Ishii, R. Takata & K. Furukawa, 1998. Fate of PCBs degrading recombinantPseudomonas putida AC30(pMFB2) and its effect on the densities of microbes in marine microcosms contaminated with PCBs. Intern. J. Envir. Stud. 55: 271–285.
Pace, M. L., 1993. Heterotrophic microbial processes. In Carpenter, S. R. & J. F. Kitchell (eds), The Trophic Cascade in Lakes. Cambridge University Press, Cambridge: 252–277.
Seto, M. & T. Tazaki, 1971. Carbon dynamic in the food chain system of glucose-Escherichia coli-Tetrahymena vorax. Jpn. J. Ecol. 21: 179–188.
Sherr, E. B., B. F. Sherr, R. D. Fallon & S. Y. Newell, 1986. Small, aloricate ciliates as a major component of the marine heterotrophic nanoplankton. Limnol. Oceanogr. 31: 177–183.
Sherr, E. & B. Sherr, 1988. Role of microbes in pelagic food webs: a revised concept. Limnol. Oceanogr. 33: 1225–1227.
Stone, L. & R. S. J. Weisburd, 1992. Positive feedback in aquatic ecosystems. Trends Ecol. Evol. 7: 263–267.
Taub, F. B. & A. M. Doller, 1968. Nutritional inadequacy of Chlorella and Chlamydomonas as food for Daphnia pulex. Limnol. Oceanogr. 13: 607–617.
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Matsui, K., Kono, S., Saeki, A. et al. Direct and indirect interactions for coexistence in a species-defined microcosm. Hydrobiologia 435, 109–116 (2000). https://doi.org/10.1023/A:1004016907260
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DOI: https://doi.org/10.1023/A:1004016907260