Abstract
Interactions between bacteria and protozoa in soil were studied over 2-week periods in the field and in a pot experiment. Under natural conditions the total biological activity was temporarily synchronized by a large rainfall, and in the laboratory by the addition of water to dried-out soil, with or without plants. In the field, peaks in numbers and biomass of bacteria appeared after the rain, and a peak of naked amoebae quickly followed. Of the three investigated groups—flagellates, ciliates, and amoebae—only populations of the latter were large enough and fluctuated in a way that indicated a role as bacterial regulators. The bacterial increase was transient, and the amoebae alone were calculated to be able to cause 60% of the bacterial decrease. The same development of bacteria and protozoa was observed in the pot experiment: in the presence of roots, amoebic numbers increased 20 times and became 5 times higher than in the unplanted soil. In the planted pots, the amoebic increase was large enough to cause the whole bacterial decrease observed; but in the unplanted soil, consumption by the amoebae caused only one-third of the bacterial decrease.
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Bååth, E., U. Lohm, B. Lundgren, T. Rosswall, B. Söderström, B. Sohlenius, and A. Wirén: The effect of nitrogen and carbon supply on the development of soil organism populations and pine seedlings; a microcosm experiment. Oikos31, 153–163 (1978)
Band, R. N.: Nutritional and related biological studies on the freeliving soil amoeba,Hartmannella rhysoides. J. Gen. Microbiol.21, 80–95 (1959)
Campbell, C. A., and V. O. Biederbeck: Soil bacterial changes as affected by growing season weather conditions. A field and laboratory study. Can. J. Soil Sci.56, 293–310 (1976)
Clarholm, M., and T. Rosswall: Biomass and turnover of bacteria in a forest soil and tundra peat. Soil Biol. Biochem.12, 49–51 (1980)
Coleman, D. C., R. V. Anderson, C. V. Cole, E. T. Elliott, L. Woods, and M. K. Campion: Trophic interactions in soils as they affect energy and nutrient dynamics. IV. Flow of metabolic and biomass carbon. Microb. Ecol.4, 373–380 (1980)
Cutler, D. W.: Soil protozoa and bacteria in relation to their environment. J. Quekett Microsc. Club. Ser. 2,15, 309–330 (1927)
Cutler, D. W., and L. M. Crump: Daily periodicity in the numbers of active soil flagellates: with a brief note on the relations of trophic amoebae and bacterial numbers. Ann. Appl. Biol.7, 11–24 (1920)
Cutler, D. W., and L. M. Crump: The qualitative and quantitative effects of food on the growth of a soil amoeba (Hartmannella hyalina). Br. J. Exp. Biol.5, 155–165 (1927)
Danso, S. K. A., and M. Alexander: Regulation of predation by prey density: The protozoan-Rhizobium relationship. Appl. Microbiol.29, 515–521 (1975)
Darbyshire, J. F., and M. P. Greaves: Protozoa and bacteria in the rhizosphere ofSinapis alba L.,Trifolium repens L. andLolium perenne L. Can. J. Microbiol.13, 1057–1068 (1967)
Darbyshire, J. F., and M. P. Greaves: Bacteria and protozoa in the rhizosphere. Pestic. Sci.4, 349–360 (1973)
Darbyshire, J. F., R. F. Wheatley, M. P. Greaves, and R. H. E. Inkson: A rapid micromethod for estimating bacterial and protozoan populations in soil. Rev. Ecol. Biol. Sol11, 465–475 (1974)
Elliott, E. T., and D. C. Coleman: Soil protozoan dynamics in a shortgrass prairie. Soil Biol. Biochem.9, 113–118 (1977)
Elliott, E. T., C. V. Cole, D. C. Coleman, R. V. Anderson, H. W. Hunt, and J. F. McClellan: Amoebal growth in soil microcosms. A model system of C, N and P. Trophic dynamics. Int. J. Environ. Stud.13, 169–174 (1979)
Elliott, E. T., D. C. Coleman, and C. V. Cole: The influence of amoebae on the uptake of nitrogen by plants in gnotobiotic soil. In J. D. Harley and R. Scott Russell (eds): The Soil Root Interface, pp. 221–229. Academic Press, New York (1979)
Fenchel, T. M., and B. Barker Jorgensen: Detritus food chains of aquatic ecosystems: The role of bacteria. Adv. Microb. Ecol.1, 1–58 (1977)
Geltzer, J. G.: On the behaviour of soil amoebae in the rhizospheres of plants. Pedobiologia2, 249–251 (1963)
Habte, M., and M. Alexander: Protozoa as agents responsible for the decline ofXanthomonas campestris in soil. Appl. Microbiol.29, 159–164 (1975)
Habte, M., and M. Alexander: Further evidence for the regulation of bacterial populations in soil by protozoa. Arch. Microbiol.113, 181–183 (1977)
Hattori, T.: Microbial Life in Soil. Marcel Dekker, New York (1973)
Jensen, A. L., and R. C. Ball: Variation in the availability of food as a cause of fluctuations in predator and prey population densities. Ecology51, 517–520 (1970)
Lynch, J. M., and L. M. Panting: Variations in the size of the soil biomass. Soil Biol. Biochem.12, 547–550 (1980)
Noland, L. F.: Factors influencing the distribution of fresh water ciliates. Ecology6, 437–452 (1925)
Ogata, S., H. Miyamoto, and S. Hayashida: An investigation of the influence of bacteriophages on the bacterial flora and purification powers of active sludge. J. Gen. Appl. Microbiol.26, 97–108 (1980)
Page, F. C.: Taxonomic criteria for limax amoebae, with descriptions of 3 new species ofHartmannella and 3 ofVahlkampfia. J. Protozool.14, 499–521 (1967)
Sohlenius, B.: A carbon budget for nematodes, rotifers and tardigrades in a Swedish coniferous forest soil. Holarctic Ecol.2, 30–40 (1979)
Stotzky, G., and A. G. Norman: Factors limiting microbial growth activities in soil. III. Supplementary substrate additions. Can. J. Microbiol.10, 143–147 (1963)
Stout, J. D.: The relationship between protozoan populations and biological activity in soils. Am. Zool.13, 193–201 (1973)
Stout, J. D.: The role of protozoa in nutrient cycling and energy flow. Adv. Microb. Ecol.4, 1–50 (1980)
Stout, J. D., and O. W. Heal: Protozoa. In A. Burges and F. Raw(eds.): Soil Biology, pp. 149–195. Academic Press, New York (1967)
Umorin, P. P.: Relationships between bacteria and flagellates in destruction of organic matter. Zh. Obshch. Biol.37, 831–835 (1976) (in Russian, English summary)
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Clarholm, M. Protozoan grazing of bacteria in soil—impact and importance. Microb Ecol 7, 343–350 (1981). https://doi.org/10.1007/BF02341429
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DOI: https://doi.org/10.1007/BF02341429